ENA Dictionary of NursingOxford University PressOxford University Press

A Dictionary of Nursing

© Oxford University Press 2000, 2003
Published by Oxford University Press, Great Clarendon Street, Oxford OX2 6DP
Oxford is a registered trade mark of Oxford University Press
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, without the prior permission in writing of Oxford University Press, or as expressly permitted by law, or under terms agreed with the appropriate reprographics rights organisation. Enquiries concerning reproduction outside the scope of the above should be sent to the Rights Department Oxford University Press.

Look up a word or term
Look up an abbreviation
Look up an affix

Pronunciation guide
A pronunciation guide is given in brackets after the entry word and before the part of speech. Words of two or more syllables are broken up into small units, usually of one syllable, separated by hyphens. The stressed syllable in a word of two or more syllables is shown in bold type.
The sounds represented are as follows:

a

as in

back (bak), active (ak-tiv)

as in

abduct (b-dukt), gamma (gam-)

ah

as in

after (ahf-ter), palm (pahm)

air

as in

aerosol (air--sol), care (kair)

ar

as in

tar (tar), heart (hart)

aw

as in

jaw (jaw), gall (gawl)

ay

as in

mania (may-nia), grey (gray)

b

as in

bed (bed)

ch

as in

chin (chin)

d

as in

day (day)

e

as in

red (red)

as in

bowel (bow-l)

ee

as in

see (see), haem (heem), caffeine (kaf-een)

eer

as in

fear (feer), serum (seer-m)

er

as in

dermal (der-ml), labour (lay-ber)

ew

as in

dew (dew), nucleus (new-kli-s)

ewr

as in

pure (pewr), dura (dewr-)

f

as in

fat (fat), phobia (foh-bi), cough (kof)

g

as in

gag (gag)

h

as in

hip (hip)

i

as in

fit (fit), acne (ak-ni), reduction (ri-duk-shn)

I

as in

eye (I), angiitis (an-ji-I-tis)

j

as in

jaw (jaw), gene (jeen), ridge (rij)

k

as in

kidney (kid-ni), chlorine (klor-een)

ks

as in

toxic (toks-ik)

kw

as in

quadrate (kwod-rayt)

l

as in

liver (liv-er)

m

as in

milk (milk)

n

as in

nit (nit)

ng

as in

sing (sing)

nk

as in

rank (rank), bronchus (bronk-s)

o

as in

pot (pot)

as in

buttock (but-k)

oh

as in

home (hohm), post (pohst)

oi

as in

boil (boil)

oo

as in

food (food), croup (kroop), fluke (flook)

oor

as in

pruritus (proor-I-ts)

or

as in

organ (or-gan), wart (wort)

ow

as in

powder (pow-der), pouch (powch)

p

as in

pill (pil)

r

as in

rib (rib)

s

as in

skin (skin), cell (sel)

sh

as in

shock (shok), action (ak-shn)

t

as in

tone (tohn)

th

as in

bath (bahth)

th

as in

then (then)

u

as in

pulp (pulp), blood (blud)

as in

typhus (ty-fs)

uu

as in

hook (huuk)

v

as in

vein (vayn)

w

as in

wind (wind)

y

as in

yeast (yeest) or, when preceded by a consonant, as in bite (byt)

yoo

as in

unit yoo-nit), formula (form-yoo-l)

yoor

as in

ureter (yoor-ee-ter)

yr

as in

fire (fyr)

z

as in

zinc (zink), glucose (gloo-kohz)

zh

as in

vision (vizh-n)

A consonant is sometimes doubled to prevent accidental mispronunciation of a syllable resembling a familiar word; for example ass-id (acid), rather than as-id; ultr-sonn-iks (ultrasonics), rather than ultr-son-iks.
An apostrophe is used (i) between two consonants forming a syllable, as in den-t'l (dental), and (ii) between two letters when the syllable might otherwise be mispronounced through resembling a familiar word, as in th'e-r-pi (therapy), th'y (thigh), and tal'k (talc).

A

a- (an-) prefix

denoting absence of; lacking; not.

Back  -    New Search

A and E medicine n.

accident and emergency medicine: an important specialty dealing with the immediate problems of the acutely ill and injured.

Back  -    New Search

ab- prefix

denoting away from.

Back  -    New Search

abarticulation (ab-ar-tik-yoo-lay-shn) n.

1 the dislocation of a joint.

2 a synovial joint (see DIARTHROSIS).
Top

Back  -    New Search

abbreviated injury scale (a-bree-vi-ay-tid) n.

a quick method for determining the severity of a case of serious trauma. It can be used for purposes of triage and clinical audit.

Back  -    New Search

abdomen (ab-dm-n) n.

the part of the body cavity below the chest (see THORAX), from which it is separated by the diaphragm. The abdomen contains the organs of digestion (stomach, liver, intestines, etc.) and excretion (kidneys, bladder, etc.) and in women reproduction. It is lined by a membrane, the peritoneum.

—abdominal (b-dom-i-nl) adj.

Back  -    New Search

abdominoperineal excision (b-dom-in-oh-pe-ri-nee-l) n.

an operation for excision of the rectum in which incisions are made in both the abdomen and the perineum.

Back  -    New Search

abducens nerve (b-dew-snz) n.

the sixth cranial nerve (VI), which supplies the lateral rectus muscle of each eyeball.

Back  -    New Search

abduct (b-dukt) vb.

to move a limb or any other part away from the midline of the body.
—abduction n.

Back  -    New Search

abductor (b-duk-ter) n.

any muscle that, when it contracts, moves one part of the body away from another or from the midline of the body. Abductors work antagonistically with adductors.

Back  -    New Search

aberrant (a-be-rnt) adj.

abnormal: usually applied to a blood vessel or nerve that does not follow its normal course.

Back  -    New Search

aberration (ab-er-ay-shn) n.

1 deviation from the normal.

2 a defect in the image formed by a lens. chromatic a. a defect in which the image has coloured fringes as a result of the different extent to which light of different colours is refracted. spherical a. a defect in which the image is blurred because curvature of the lens causes light rays from the object to come to a focus in slightly different positions.
Top

Back  -    New Search

ablation (b-lay-shn) n.

surgical removal of tissue, a part of the body, or an abnormal growth, usually by cutting. See also ENDOMETRIAL (ABLATION).

Back  -    New Search

abnormal (ab-nor-ml) adj.

deviating from the normal in structure, position, occurrence, etc.: an abnormal growth .

Back  -    New Search

abnormality (ab-nor-mal-iti) n.

1 deviation from the normal or expected.

2 a malformation of deformity: a developmental abnormality .
Top

Back  -    New Search

abort (-bort) vb.

1 to terminate a process or disease before its full course has been run.

2 to remove or expel an embryo or fetus from the uterus before it is capable of independent existence. See ABORTION.
Top

Back  -    New Search

abortifacient (-bor-ti-fay-shnt) n.

a drug that induces abortion or miscarriage.

Back  -    New Search

abortion (-bor-shn) n.

the expulsion or removal of an embryo or fetus from the uterus at a stage of pregnancy when it is incapable of independent survival (i.e. at any time between conception and the 24th week of pregnancy). complete a. premature expulsion of the fetus and all its membranes. criminal a. (in Britain) abortion not carried out within the terms of the Abortion Act 1967. habitual (or recurrent ) a. abortion occurring in three or more successive pregnancies before 20 weeks' gestation, with fetuses weighing under 500 g. incomplete a. retention by the uterus of part of the fetus or its membranes during an abortion. induced a. the deliberate termination of a pregnancy for medical or social reasons. inevitable a. abortion that cannot be prevented as the fetus is dead. missed a. abortion in which the fetus is dead but not expelled from the uterus. recurrent a. see HABITUAL A. spontaneous a. miscarriage; naturally occurring abortion. therapeutic a. abortion induced to protect the life or health of the mother. threatened a. abdominal pain and bleeding from the uterus while the fetus is still alive.
—abortionist n. —abortive adj.

Back  -    New Search

abortus (-bor-ts) n.

a fetus, weighing less than 500 g, that is expelled from the uterus either dead or incapable of surviving.

Back  -    New Search

ABO system n.

see BLOOD GROUP.

Back  -    New Search

abrasion (-bray-zhn) n.

a minor wound in which the surface of the skin or a mucous membrane is worn away by rubbing or scraping.

Back  -    New Search

abreaction (ab-ree-ak-shn) n.

the release of strong emotion associated with a buried memory. Abreaction may be induced as a treatment for conversion disorder, anxiety state, and other neurotic conditions.

Back  -    New Search

abruptio placentae (-brup-ti-oh pl-sent-i) n.

bleeding from the placenta causing its complete or partial detachment from the uterine wall after the 24th week of gestation. Abruptio placentae is often associated with hypertension and pre-eclampsia.

Back  -    New Search

abscess (ab-sis) n.

a collection of pus enclosed by damaged and inflamed tissues. acute a. an abscess associated with pain, inflammation, and some fever. apical a. an abscess in the bone around the tip of the root of a tooth. Brodie's a. a chronic abscess of bone that develops from acute bacterial osteomyelitis. cerebral a. an abscess resulting from infection of the brain or its meninges. cold or chronic a. an abscess, usually due to tuberculosis organisms, in which there is little pain or inflammation. psoas a. a cold abscess in the psoas muscle (in the groin), which has spread from diseased vertebrae in the lower part of the spine. subphrenic a. an abscess in the space below the diaphragm, usually resulting from a spread of infection from the abdomen. tropical (or amoebic ) a. an abscess of the liver caused by infection with Entamoeba histolytica. See also ISCHIORECTAL ABSCESS.

Back  -    New Search

absence (ab-sns) n.

(in neurology) see EPILEPSY.

Back  -    New Search

absorption (b-sorp-shn) n.

the uptake of digested food from the intestine into the blood and lymphatic systems. See also ASSIMILATION, DIGESTION.

Back  -    New Search

abulia (-boo-li) n.

absence or impairment of will power, commonly a symptom of schizophrenia.

Back  -    New Search

acanthosis (ak-n-thoh-sis) n.

an increase in the number of prickle cells in the innermost layer of the epidermis, leading to thickening of the epidermis. a. nigricans acanthosis characterized by papillomatous growths, mainly in the armpits, which give the skin a pigmented appearance and a velvety texture. It may be benign or malignant.

Back  -    New Search

acapnia (hypocapnia) (-kap-ni) n.

a condition in which there is an abnormally low concentration of carbon dioxide in the blood.

Back  -    New Search

acardia (ay-kar-di) n.

congenital absence of the heart. The condition may occur in conjoined twins; the twin with the heart controls the circulation for both.

Back  -    New Search

acariasis (ak-ry--sis) n.

an infestation of mites and ticks.

Back  -    New Search

acaricide (-ka-ri-syd) n.

any chemical agent used for destroying mites and ticks.

Back  -    New Search

acatalasia (-kat--lay-zi) n.

an inborn lack of the enzyme catalase, leading to recurrent infections of the gums (gingivitis) and mouth.

Back  -    New Search

accessory nerve (spinal accessory nerve) (k-sess-er-i) n.

the eleventh cranial nerve (XI), which arises from two roots, cranial and spinal. Fibres from the cranial root form the recurrent laryngeal nerve, which supplies the internal laryngeal muscles; fibres from the spinal root supply the sternomastoid and trapezius muscles, in the neck region.

Back  -    New Search

accident (ak-sid-nt) n.

a traumatic incident involving any part of the body. Accident and emergency (A and E) medicine is evolving as a specialized area of patient care.

Back  -    New Search

accommodation (-kom--day-shn) n.

adjustment of the shape of the lens to change the focus of the eye. When the ciliary muscle (see CILIARY BODY) is relaxed, the lens is flattened and the eye is then able to focus on distant objects. To focus the eye on near objects the ciliary muscles contract and the lens becomes more spherical. a. reaction the constriction of the pupil that occurs when an individual focuses on a near object.

Back  -    New Search

accouchement (-koosh-mahnt) n.

delivery of a baby. hydrostatic a. the management of normal labour with the mother partially immersed in a water bath.

Back  -    New Search

accountability (-kownt--bil-iti) n.

(in nursing) the obligation of being answerable for one's own judgments and actions to an appropriate person or authority recognized as having the right to demand information and explanation, according to the terms of reference of the Code of Professional Conduct see Code of Professional Conduct for the Nurse, Midwife, and Health Visitor. A registered practitioner (nurse, midwife, health visitor) is accountable for her actions as a professional at all times, on or off duty, whether engaged in current practice or not.

Back  -    New Search

accreditation (-kred-i-tay-shn) n.

1 formal recognition by an organization of an individual as an approved and acknowledged representative, e.g. of a union or staff organization.

2 (in the USA, Australasia, and some European countries) the licensing of a hospital by government agencies, subject to its meeting certain prerequisite conditions.
Top

Back  -    New Search

accretion (-kree-shn) n.

the accumulation of deposits in an organ or cavity. Calculi may be formed by accretion.

Back  -    New Search

acebutolol (ass-i-bew-toh-lol) n.

a beta blocker drug commonly used to treat high blood pressure, angina pectoris, and irregular heart rhythms. It is administered by mouth. Trade name: Sectral .

Back  -    New Search

ACE inhibitor (ayss) n.

angiotensin-converting enzyme inhibitor: any one of a group of drugs used in the treatment of raised blood pressure and heart failure. ACE inhibitors act by interfering with the action of the enzyme that converts the inactive angiotensin I to the powerful artery constrictor angiotensin II. ACE inhibitors are administered by mouth; they include captopril and enalapril.

Back  -    New Search

acephalus (-sef--ls) n.

a fetus without a head.
—acephalous adj.

Back  -    New Search

acetabuloplasty (ass-i-tab-yoo-loh-plas-ti) n.

an operation in which the shape of the acetabulum is modified to correct congenital dislocation of the hip or to treat osteoarthritis.

Back  -    New Search

acetabulum (cotyloid cavity) (ass-i-tab-yoo-lm) n. (pl. acetabula)

either of the two deep sockets, one on each side of the hip bone, into which the head of the thigh bone (femur) fits at the hip joint.

Back  -    New Search

acetaminophen (ass-ee-t-min--fen) n.

see PARACETAMOL.

Back  -    New Search

acetate (ass-it-ayt) n.

any salt or ester of acetic acid.

Back  -    New Search

acetazolamide (ass-ee-t-zol--myd) n.

a diuretic used in the treatment of glaucoma to reduce the pressure inside the eyeball and also as a preventative for altitude sickness. Trade name: Diamox .

Back  -    New Search

acetic acid (-see-tik) n.

the acid that is present in vinegar. It is used in the preparation of astringent and antiseptic medicines and in urine testing. Formula:
CH_3COOH
.

Back  -    New Search

acetoacetic acid (ass-i-toh--see-tik) n.

an organic acid produced in large amounts by the liver in such conditions as starvation. Formula:
CH_3COCH_2COOH
. See also KETONE.

Back  -    New Search

acetohexamide (ass-i-toh-heks--myd) n.

a drug that reduces the level of blood sugar, administered by mouth in the treatment of noninsulin-dependent diabetes mellitus. See ORAL HYPOGLYCAEMIC DRUG.

Back  -    New Search

acetonaemia (ass-i-toh-nee-mi) n.

the presence of acetone bodies in the blood. See KETONE.

Back  -    New Search

acetone (ass-i-tohn) n.

an organic compound that is produced by the liver in such conditions as starvation. Acetone is of great value as a solvent. Formula:
CH_3COCH_3
. See also KETONE.

Back  -    New Search

acetone body (ketone body) n.

see KETONE.

Back  -    New Search

acetonuria (ass-i-toh-newr-i) n.

see KETONURIA.

Back  -    New Search

acetylcholine (ass-i-tyl-koh-leen) n.

the acetic acid ester of the organic base choline: the neurotransmitter released at the synapses of parasympathetic nerves and at neuromuscular junctions. See also CHOLINESTERASE.

Back  -    New Search

acetylcoenzyme A (ass-i-tyl-koh-en-zym) n.

a compound formed by the combination of an acetate molecule with coenzyme A. Acetylcoenzyme A has an important role in the Krebs cycle.

Back  -    New Search

acetylcysteine (ass-i-tyl-siss-ti-een) n.

a drug that is administered as an aerosol for the treatment of respiratory diseases, such as bronchitis and cystic fibrosis; it is also used to prevent liver damage in paracetamol overdosage. Trade names: Fabrol , Parvolex .

Back  -    New Search

acetylsalicylic acid (ass-i-tyl-sa-li-sil-ik) n.

see ASPIRIN.

Back  -    New Search

achalasia (cardiospasm) (ak--lay-zi) n.

a condition in which the normal muscular activity of the oesophagus (gullet) is disturbed, especially failure of an abnormally strong sphincter at the lower end, which delays the passage of swallowed material.

Back  -    New Search

Achilles tendon (-kil-eez) n.

the tendon of the muscles of the calf of the leg (the gastrocnemius and soleus muscles), situated at the back of the ankle and attached to the calcaneus (heel bone).

Back  -    New Search

achillorrhaphy (ak-i-lo-rfi) n.

surgical repair of the Achilles tendon.

Back  -    New Search

achillotomy (ak-i-lot-mi) n.

surgical division of the Achilles tendon.

Back  -    New Search

achlorhydria (ay-klor-hy-dri) n.

absence of hydrochloric acid in the stomach. It is sometimes associated with pernicious anaemia.

Back  -    New Search

acholia (-koh-li) n.

absence or deficiency of bile secretion or failure of the bile to enter the alimentary canal.

Back  -    New Search

acholuria (ak-oh-lewr-i) n.

absence of the bile pigments from the urine, which occurs in some forms of jaundice (acholuric jaundice ).
—acholuric adj.

Back  -    New Search

achondroplasia (-kon-droh-play-zi) n.

a disorder, inherited as a dominant characteristic, in which the bones of the arms and legs fail to grow to normal size. It results in a type of dwarfism characterized by short limbs, a normal-sized head and body, and normal intelligence.
—achondroplastic (-kon-droh-plas-tik) adj.

Back  -    New Search

achromatic (ak-roh-mat-ik) adj.

without colour.
—achromasia (ak-roh-may-zi) n.

Back  -    New Search

achromatopsia (-kroh-m-top-si) n.

the inability to perceive colour. Such complete colour blindness is very rare and is usually determined by hereditary factors.

Back  -    New Search

achylia (-ky-li) n.

absence of secretion. a. gastrica a nonsecreting stomach whose lining (mucosa) is atrophied.

Back  -    New Search

acid (ass-id) n.

a substance that releases hydrogen ions when dissolved in water, has a pH below 7 and turns litmus paper red, and reacts with a base to form a salt and water only. Compare BASE.

Back  -    New Search

acidaemia (asid-ee-mi) n.

a condition of abnormally high blood acidity. See also ACIDOSIS. Compare ALKALAEMIA.

Back  -    New Search

acid-base balance n.

the balance between the amount of carbonic acid and bicarbonate in the blood, which must be maintained at a constant ratio of 1:20 in order to keep the hydrogen ion concentration of the plasma at a constant value (pH 7.4).

Back  -    New Search

acid-fast adj.

1 describing bacteria that have been stained and continue to hold the stain after treatment with an acidic solution.

2 describing a stain that is not removed from a specimen by washing with an acidic solution.
Top

Back  -    New Search

acidity (-sid-iti) n.

the state of being acid. The degree of acidity of a solution is measured on the pH scale (see pH).

Back  -    New Search

acidosis (asid-oh-sis) n.

a condition in which the acidity of body fluids and tissues is abnormally high. This arises because of a failure of the mechanisms responsible for maintaining a balance between acids and alkalis in the blood (see ACID-BASE BALANCE).
—acidotic (asid-ot-ik) adj.

Back  -    New Search

acid phosphatase n.

an enzyme secreted in the seminal fluid by the prostate gland.

Back  -    New Search

acinus (ass-in-s) n. (pl. acini)

1 a small sac or cavity surrounded by the secretory cells of a gland.

2 (in the lung) the tissue supplied with air by one terminal bronchiole.
Top

—acinous adj.

Back  -    New Search

aclarubicin (ak-l-roo-bi-sin) n.

an antimitotic drug administered by injection in the treatment of leukaemia and other cancers. It is an anthracycline antibiotic. Trade name: Aclacin .

Back  -    New Search

acne (acne vulgaris) (ak-ni vul-gar-iss) n.

a common inflammatory disorder of the sebaceous glands. It involves the face, back, and chest and is characterized by the presence of blackheads with papules, pustules, and – in more severe cases – cysts and scars. Mild cases respond to topical therapy with benzoyl peroxide, while more refractory conditions require treatment with long-term antibiotics.

Back  -    New Search

acoustic (-koo-stik) adj.

of or relating to sound or the sense of hearing. a. holography a technique of building up a three-dimensional picture of structures within the body using ultrasound waves. a. nerve see VESTIBULOCOCHLEAR NERVE.

Back  -    New Search

acquired (-kwyrd) adj.

describing a condition or disorder contracted after birth and not attributable to hereditary causes. Compare CONGENITAL.

Back  -    New Search

acquired immune deficiency syndrome n.

see AIDS.

Back  -    New Search

acriflavine (ak-ri-flay-vin) n.

a dye used in antiseptic skin preparations and to disinfect contaminated wounds.

Back  -    New Search

acrivastine (ak-ri-vas-teen) n.

an antihistamine drug used to treat hay fever and urticaria (nettle rash). It is administered by mouth. Trade name: Semprex .

Back  -    New Search

acro- prefix

denoting 1 extremity; tip.

2 height; promontory.
Top

3 extreme; intense.
Top

Back  -    New Search

acrocentric (ak-roh-sen-trik) n.

a chromosome in which the centromere is situated at or very near one end.
—acrocentric adj.

Back  -    New Search

acrocyanosis (ak-roh-sy--noh-sis) n.

bluish-purple discoloration of the hands and feet due to slow circulation of the blood through the small vessels in the skin.

Back  -    New Search

acrodynia (ak-roh-din-i) n.

see PINK DISEASE.

Back  -    New Search

acromegaly (ak-roh-meg-li) n.

increase in size of the hands, feet, and the face due to excessive production of growth hormone by a tumour of the anterior pituitary gland. See also GIGANTISM.

Back  -    New Search

acromion (-kroh-mi-n) n.

an oblong process at the top of the spine of the scapula, part of which articulates with the clavicle (collar bone) to form the acromio-clavicular joint
—acromial adj.

Back  -    New Search

acronyx (ak-r-niks) n.

an ingrowing toenail or fingernail. See INGROWING TOENAIL.

Back  -    New Search

acroparaesthesiae (ak-roh-pa-ris-theez-i-ee) pl. n.

tingling sensations in the hands and feet.

Back  -    New Search

acrophobia (ak-r-foh-bi) n.

a morbid dread of heights.

Back  -    New Search

acrosclerosis (ak-roh-skleer-oh-sis) n.

a skin disease thought to be a type of generalized scleroderma, mainly affecting the hands, face, and feet.

Back  -    New Search

acrosome (ak-r-sohm) n.

the caplike structure on the front end of a spermatozoon.

Back  -    New Search

ACTH (adrenocorticotrophic hormone, adrenocorticotrophin, corticotrophin) n.

a hormone synthesized and stored in the anterior pituitary gland, controlling the secretion of corti-costeroid hormones from the adrenal gland. It is administered by injection to treat conditions such as rheumatic diseases (especially in children) and asthma.

Back  -    New Search

actin (ak-tin) n.

a protein, found in muscle, that plays an important role in the process of contraction. See STRIATED MUSCLE.

Back  -    New Search

Actinomyces (ak-ti-noh-my-seez) n.

a genus of Gram-positive nonmotile fungus-like bacteria that cause disease in animals and man. A. israelii the causative organism of human actinomycosis.

Back  -    New Search

actinomycin (ak-ti-noh-my-sin) n.

a cytotoxic drug that inhibits the growth of cancer cells. There are two forms, actinomycin C and actinomycin D, both of which are administered by injection.

Back  -    New Search

actinomycosis (ak-ti-noh-my-koh-sis) n.

a noncontagious disease caused by the bacterium Actinomyces israelii and resulting in the formation of multiple sinuses that open onto the skin. Actinomycosis most commonly affects the jaw but may also affect the lungs, brain, or intestines.

Back  -    New Search

actinotherapy (ak-ti-noh-th'e-r-pi) n.

the treatment of disorders with infrared or ultraviolet radiation.

Back  -    New Search

action potential (ak-shn) n.

the change in voltage that occurs across the membrane of a nerve or muscle cell when a nerve impulse is triggered.

Back  -    New Search

activator (ak-ti-vay-ter) n.

a substance that stimulates a chemical change or reaction.

Back  -    New Search

active movement (ak-tiv) n.

movement brought about by a patient's own efforts. Compare PASSIVE MOVEMENT.

Back  -    New Search

active principle n.

an ingredient of a drug that is actively involved in its therapeutic effect.

Back  -    New Search

activities of daily living (activities of living, ADLs, ALs) (ak-tiv-it-iz) pl. n.

the routine activities that an individual does for himself during the course of the day, such as eating, drinking, and washing. See ROPER, LOGAN, AND TIERNEY MODEL.

Back  -    New Search

actomyosin (ak-toh-my-oh-sin) n.

a protein complex formed in muscle between actin and myosin during the process of contraction. See STRIATED MUSCLE.

Back  -    New Search

acupuncture (ak-yoo-punk-cher) n.

a traditional Chinese system of healing in which thin metal needles are inserted into selected points beneath the skin to relieve pain or induce anaesthesia.

Back  -    New Search

acute (-kewt) adj.

1 describing a disease of rapid onset, severe symptoms, and brief duration. Compare CHRONIC.

2 describing any intense symptom, such as severe pain.
Top

Back  -    New Search

acute abdomen n.

an emergency surgical condition caused by damage to one or more abdominal organs following injury or disease.

Back  -    New Search

acute rheumatism n.

see RHEUMATIC FEVER.

Back  -    New Search

acyclovir (ay-sy-kloh-veer) n.

an antiviral drug that inhibits DNA synthesis in cells infected by herpesviruses. Administered topically, by mouth, or intravenously, it is useful in patients whose immune systems are disturbed and also in the treatment of herpes zoster, genital herpes, and herpes encephalitis. Trade name: Zovirax .

Back  -    New Search

acystia (-sis-ti) n.

congenital absence of the bladder.

Back  -    New Search

ad- prefix

denoting towards or near.

Back  -    New Search

ADA deficiency n.

see ADENOSINE DEAMINASE DEFICIENCY.

Back  -    New Search

Adam's apple (laryngeal prominence) (ad-mz) n.

a projection, lying just under the skin, of the thyroid cartilage of the larynx.

Back  -    New Search

adaptation (ad-p-tay-shn) n.

the phenomenon in which a sense organ shows a gradually diminishing response to continuous or repetitive stimulation.

Back  -    New Search

ADD n.

see ATTENTION DEFICIT DISORDER.

Back  -    New Search

addiction (-dik-shn) n.

a state of dependence produced by the habitual taking of drugs. See also ALCOHOLISM, TOLERANCE.

Back  -    New Search

Addison's disease (ad-i-snz) n.

a syndrome due to inadequate secretion of corticosteroid hormones by the adrenal glands. Symptoms include weakness, loss of energy, low blood pressure, and dark pigmentation of the skin. [T. Addison (1793–1860), British physician]

Back  -    New Search

adduct (-dukt) vb.

to move a limb or any other part towards the midline of the body.
—adduction n.

Back  -    New Search

adductor (-duk-ter) n.

any muscle that moves one part of the body towards another or towards the midline of the body.

Back  -    New Search

aden- (adeno-) prefix

denoting a gland or glands.

Back  -    New Search

adenine (ad--neen) n.

one of the nitrogen-containing bases (see PURINE) that occurs in the nucleic acids DNA and RNA. See also ATP.

Back  -    New Search

adenitis (ad--ny-tis) n.

inflammation of one or more glands or lymph nodes.

Back  -    New Search

adenocarcinoma (ad-in-oh-kar-si-noh-m) n. (pl. adenocarcinomata)

a malignant epithelial tumour arising from glandular tissue. The term is also applied to tumours showing a glandular growth pattern.

Back  -    New Search

adenohypophysis (ad-in-oh-hy-pof-i-sis) n.

see PITUITARY GLAND.

Back  -    New Search

adenoidectomy (ad-in-oid-ek-tmi) n.

surgical removal of the adenoids.

Back  -    New Search

adenoids (nasopharyngeal tonsil) (ad-in-oidz) n.

the collection of lymphatic tissue at the rear of the nose. Enlargement of the adenoids can cause obstruction to breathing through the nose and can block the Eustachian tubes, causing glue ear.

Back  -    New Search

adenolymphoma (ad-in-oh-lim-foh-m) n.

see WARTHIN'S TUMOUR.

Back  -    New Search

adenoma (ad-in-oh-m) n. (pl. adenomata)

a benign tumour of epithelial origin that is derived from glandular tissue or exhibits clearly defined glandular structures. Adenomas may become malignant (see ADENOCARCINOMA).

Back  -    New Search

adenomyoma (ad-in-oh-my-oh-m) n.

a benign tumour derived from glandular and muscular tissue. Adenomyomas frequently occur in the uterus.

Back  -    New Search

adenomyosis (ad-in-oh-my-oh-sis) n.

the infiltration of tissue resembling endometrium into the wall of the uterus. See ENDOMETRIOSIS.

Back  -    New Search

adenopathy (ad-in-op-thi) n.

disease of a gland or glandlike structure, especially a lymph node.

Back  -    New Search

adenosclerosis (ad-in-oh-skleer-oh-sis) n.

hardening of a gland, usually due to calcification.

Back  -    New Search

adenosine (-den--seen) n.

a compound containing adenine and the sugar ribose: it occurs in ATP. See also NUCLEOSIDE.

Back  -    New Search

adenosine deaminase deficiency (ADA deficiency) (dee-am-in-ayz) n.

a genetic disorder characterized by a defect in the enzyme adenosine deaminase (ADA), which is involved in purine metabolism. Deficiency of this enzyme results in damage to the antibody-producing lymphocytes, which leads to severe combined immunodeficiency disease (SCID).

Back  -    New Search

adenosine diphosphate n.

see ADP.

Back  -    New Search

adenosine monophosphate n.

see AMP.

Back  -    New Search

adenosine triphosphate n.

see ATP.

Back  -    New Search

adenosis (ad-in-oh-sis) n. (pl. adenoses)

1 excessive growth or development of glands.

2 any disease of a gland or gland-like structure, especially of a lymph node.
Top

Back  -    New Search

adenovirus (ad-in-oh-vy-rs) n.

one of a group of DNA-containing viruses causing infections of the upper respiratory tract that produce symptoms resembling those of the common cold.

Back  -    New Search

adhesion (d-hee-zhn) n.

1 the union of two normally separate surfaces by fibrous connective tissue developing in an inflamed or damaged region. (The fibrous tissue itself is also called an adhesion.) Adhesions between loops of intestine often occur following abdominal surgery but only rarely cause symptoms, such as intestinal obstruction.

2 a healing process in which the edges of a wound fit together.
Top

Back  -    New Search

adiadochokinesis (-dy--doh-koh-ki-nee-sis) n.

see DYSDIADOCHOKINESIS.

Back  -    New Search

adiaphoresis (-dy--f-ree-sis) n.

deficient or reduced secretion of sweat.
—adiaphoretic (-dy--f-ret-ik) adj.

Back  -    New Search

Adie's pupil (ay-diz) n.

see TONIC (PUPIL). [W. J. Adie (1886–1935), British physician]

Back  -    New Search

adipose tissue (ad-i-pohs) n.

fibrous connective tissue packed with masses of fat cells. It forms a thick layer under the skin and occurs around the kidneys and in the buttocks.

Back  -    New Search

adiposis (liposis) (ad-i-poh-sis) n.

the presence of abnormally large accumulations of fat in the body. The condition may arise from overeating, hormone irregularities, or a metabolic disorder. See also OBESITY.

Back  -    New Search

adiposuria (ad-i-poh-sewr-i) n.

see LIPURIA.

Back  -    New Search

aditus (ad-i-ts) n.

an anatomical opening or passage; for example, the opening of the tympanic cavity (middle ear) to the air spaces of the mastoid process.

Back  -    New Search

adjuvant (aj-oo-vnt) n.

any substance used in conjunction with another to enhance its activity.

Back  -    New Search

adjuvant therapy n.

cytotoxic drug treatment given to some patients after surgical removal of, or radiotherapy to, their primary tumour when there is known to be a high risk of future tumour recurrence arising from micrometastases. Compare NEOADJUVANT CHEMOTHERAPY.

Back  -    New Search

adnexa (ad-neks-) pl. n.

adjoining parts. uterine a. the Fallopian tubes and ovaries.

Back  -    New Search

adolescence (ad--less-ns) n.

the period of development between childhood and adulthood. It begins with the start of puberty.
—adolescent n., adj.

Back  -    New Search

ADP (adenosine diphosphate) n.

a compound containing adenine, ribose, and two phosphate groups. ADP occurs in cells and is involved in processes requiring the transfer of energy (see ATP).

Back  -    New Search

adrenalectomy (-dree-nl-ek-tmi) n.

surgical removal of one or both adrenal glands.

Back  -    New Search

adrenal glands (suprarenal glands) (-dree-nl) pl. n.

two triangular endocrine glands, each of which covers the superior surface of a kidney. The medulla forms the grey core of the gland and produces adrenaline and noradrenaline. The cortex is a yellowish tissue surrounding the medulla; it produces corticosteroid hormones.

Back  -    New Search

adrenaline (epinephrine) (-dren--lin) n.

an important hormone secreted by the medulla of the adrenal gland. It has widespread effects on circulation, the muscles, and sugar metabolism. The action of the heart is increased, the rate and depth of breathing are increased, and the metabolic rate is raised; the force of muscular contraction improves and the onset of muscular fatigue is delayed. At the same time the blood supply to the bladder and intestines is reduced, their muscular walls relax, and the sphincters contract. Adrenaline is administered by injection for the relief of bronchial asthma; it is also used during surgery or by injection through an endoscope to reduce blood loss by constricting vessels in the skin or mucous membranes. It is included in some local anaesthetic solutions, particularly those used in dentistry, to prolong anaesthesia.

Back  -    New Search

adrenergic (ad-r-ner-jik) adj.

describing or relating to nerve fibres that release noradrenaline as a neurotransmitter. a. receptor a receptor at which noradrenaline acts to pass on messages from sympathetic nerves. Compare CHOLINERGIC.

Back  -    New Search

adrenocorticotrophic hormone (adrenocorticotrophin) (-dree-noh-kor-ti-koh-trof-ik) n.

see ACTH.

Back  -    New Search

adrenogenital syndrome (-dree-noh-jen-it-l) n.

a hormonal disorder resulting from abnormal steroid production by the adrenal cortex, due to a genetic fault. It may cause masculinization in girls, precocious puberty in boys, and adrenocortical failure (see ADDISON'S DISEASE) in both sexes. Treatment is by lifelong steroid replacement.

Back  -    New Search

adrenoleukodystrophy (-dree-noh-loo-koh-dis-tr-fi) n.

a genetically determined condition of neurological degeneration with childhood and adult forms. It is characterized by abnormal fatty-acid metabolism with progressive spastic paralysis of the legs and sensory loss, associated with adrenal gland insufficiency and small gonads.

Back  -    New Search

adrenolytic (-dree-noh-lit-ik) adj.

inhibiting the activity of adrenergic nerves. Adrenolytic activity is opposite to that of adrenaline.

Back  -    New Search

adsorbent (d-sor-bnt) n.

a substance that attracts other substances to its surface to form a film. Charcoal and kaolin are adsorbents.

Back  -    New Search

adsorption (d-sorp-shn) n.

the formation of a layer of atoms or molecules of one substance on the surface of a solid or liquid of different substance. See ABSORBENT.

Back  -    New Search

adult respiratory distress syndrome (ARDS) (ad-ult) n.

a form of acute respiratory failure that occurs after a precipitating event, such as trauma, aspiration, or inhalation of a toxic substance; it is particularly associated with septic shock.

Back  -    New Search

advancement (d-vahns-mnt) n.

the detachment by surgery of a muscle, musculocutaneous flap, or tendon and its reattachment at a more advanced (anterior) point. The technique is used, for example, in the treatment of squint, and extensively in plastic surgery.

Back  -    New Search

adventitia (tunica adventitia) (ad-ven-ti-sh) n.

1 the outer coat of the wall of a vein or artery.

2 the outer covering of various other organs or parts.
Top

Back  -    New Search

adventitious (ad-ven-ti-shs) adj.

1 occurring in a place other than the usual one.

2 relating to the adventitia.
Top

Back  -    New Search

advocate (ad-v-kt) n.

(in health care) a practitioner, usually a nurse, who utilizes her role to promote and safeguard the wellbeing and interests of her patients or clients by ensuring they are aware of their rights and have access to information to make informed decisions. Advocacy in health care is an integral part of professional practice.

Back  -    New Search

Aëdes (ay-ee-deez) n.

a genus of widely distributed mosquitoes occurring throughout the tropics and subtropics. A. aegypti the principal vector of dengue and yellow fever.

Back  -    New Search

aegophony (e-gof-ni) n.

see VOCAL RESONANCE.

Back  -    New Search

-aemia suffix

denoting a specified condition of the blood.

Back  -    New Search

aer- (aero-) prefix

denoting air or gas.

Back  -    New Search

aerobe (air-ohb) n.

any organism, especially a microbe, that requires the presence of free oxygen for life and growth. Compare ANAEROBE.
—aerobic (air-oh-bik) adj.

Back  -    New Search

aerobic exercise n.

see EXERCISE.

Back  -    New Search

aerobic respiration n.

a type of cellular respiration in which foodstuffs (carbohydrates) are completely oxidized by atmospheric oxygen, with the production of maximum chemical energy from the foodstuffs.

Back  -    New Search

aerogenous (air-oj-in-s) adj.

producing gas. The term is applied to bacteria such as Clostridium perfringens, which causes gas gangrene.

Back  -    New Search

aerophagy (air-off-ji) n.

the swallowing of air. Voluntary aerophagy is used to permit oesophageal speech after surgical removal of the larynx (usually for cancer).

Back  -    New Search

aerosol (air--sol) n.

a suspension of extremely small liquid or solid particles in the air. Drugs in aerosol form may be administered by inhalation.

Back  -    New Search

aetiology (etiology) (ee-ti-ol-ji) n.

1 the study or science of the causes of disease.

2 the cause of a specific disease.
Top

Back  -    New Search

afebrile (ay-feb-ryl) adj.

without, or not showing any signs of, a fever.

Back  -    New Search

affect (af-ekt) n.

(in psychiatry) 1 the predominant emotion in a person's mental state.

2 the emotion associated with a particular idea.
Top

—affective (-fek-tiv) adj.

Back  -    New Search

affective disorder (dis-or-der) n.

any psychiatric disorder featuring abnormalities of mood or emotion (affect). The most serious of these are depression and mania. Other affective disorders include SADS (seasonal affective disorder syndrome).

Back  -    New Search

afferent (af-er-nt) adj.

1 designating nerves or neurones that convey impulses to the brain or spinal cord.

2 designating blood vessels that feed a capillary network in an organ or part.
Top

3 designating lymphatic vessels that enter a lymph node. Compare EFFERENT.
Top

Back  -    New Search

affinity (-fin-iti) n.

the chemical attraction of one substance to another or others.

Back  -    New Search

aflatoxin (af-l-toks-in) n.

a poisonous substance produced in the spores of the fungus Aspergillus flavus, which infects peanuts. It is known to produce cancer in certain animals.

Back  -    New Search

afterbirth (ahf-ter-berth) n.

the placenta, umbilical cord, and ruptured membranes associated with the fetus, which normally become detached from the uterus and expelled within a few hours of birth.

Back  -    New Search

aftercare (ahf-ter-kair) n.

1 long-term surveillance as an adjunct or supplement to formal medical treatment of those who are chronically sick or disabled. Aftercare includes the provision of special aids and the adaptation of homes to improve daily living.

2 surveillance of convalescents.
Top

Back  -    New Search

after-image (ahf-ter-im-ij) n.

an impression of an image that is registered by the brain for a brief moment after an object is removed from in front of the eye, or after the eye is closed.

Back  -    New Search

afterpains (ahf-ter-paynz) pl. n.

pains caused by uterine contractions after child-birth, especially during breast feeding, due to release of the hormone oxytocin.

Back  -    New Search

agammaglobulinaemia (-gam--glob-yoo-lin-ee-mi) n.

a total deficiency of the plasma protein gammaglobulin. Compare HYPOGAMMAGLOBULINAEMIA.

Back  -    New Search

agar (ay-ger) n.

an extract of certain seaweeds that forms a gel suitable for the solidification of liquid bacteriological culture media. Agar may also be used as a laxative.

Back  -    New Search

agenesis (-jen-sis) n.

absence of an organ, usually due to total failure of its development in the embryo.

Back  -    New Search

age-related macular degeneration (ayj-ri-lay-tid) n.

see MACULAR DEGENERATION.

Back  -    New Search

agglutination (clumping) (-gloo-tin-ay-shn) n.

the sticking together of such microscopic antigenic particles as red blood cells or bacteria so that they form visible clumps.
—agglutinative adj.

Back  -    New Search

agglutinin (-gloo-tin-in) n.

an antibody that brings about the agglutination of bacteria, blood cells, or other antigenic particles.

Back  -    New Search

agglutinogen (-gloo-tin-oh-jn) n.

any antigen that provokes formation of an agglutinin in the serum and is therefore likely to be involved in agglutination.

Back  -    New Search

aglossia (-gloss-i) n.

congenital absence of the tongue.

Back  -    New Search

aglutition (a-gloo-ti-shn) n.

inability to swallow. See also DYSPHAGIA.

Back  -    New Search

agnosia (ag-noh-zi) n.

a disorder of the brain whereby the patient cannot interpret sensations correctly although the sense organs and nerves conducting sensation to the brain are functioning normally.

Back  -    New Search

agonist (ag--nist) n.

1 (prime mover ) a muscle whose active contraction causes movement of a part of the body. Contraction of an agonist is associated with relaxation of its antagonist.

2 a drug or other substance that acts at a cell-receptor site to produce an effect that is the same as, or similar to, that of the body's normal chemical messenger. Cholinergic drugs (see PARASYMPATHOMIMETIC) are examples.
Top

Back  -    New Search

agoraphobia (ag-er--foh-bi) n.

a morbid fear of public places and/or of open spaces. See also PHOBIA.

Back  -    New Search

agranulocytosis (-gran-yoo-loh-sy-toh-sis) n.

a disorder in which there is a severe acute deficiency of certain blood cells (neutrophils) as a result of damage to the bone marrow by toxic drugs or chemicals. It is characterized by fever, with ulceration of the mouth and throat, and may lead rapidly to prostration and death.

Back  -    New Search

agraphia (dysgraphia) (-graf-i) n.

an acquired inability to write, although the strength and coordination of the hand remain normal.

Back  -    New Search

ague (ay-gew) n.

see MALARIA.

Back  -    New Search

AIDS (acquired immune deficiency syndrome) (aydz) n.

a syndrome caused by the human immunodeficiency virus (HIV), which destroys a subgroup of lymphocytes, resulting in suppression of the body's immune response (see (HELPER) T-CELL). AIDS is essentially a sexually transmitted disease, either homosexually or heterosexually, but it can also be spread via infected blood or blood products and from an infected mother to her child in the uterus, during parturition, or in breast milk.
Acute infection following exposure to the virus results in the production of antibodies (seroconversion), but not all those who seroconvert progress to chronic infection. The chronic stage may include persistent generalized involvement of the lymph nodes; AIDS-related complex (ARC), including intermittent fever, weight loss, diarrhoea, fatigue, and night sweats; and AIDS itself, presenting as opportunistic infections (especially pneumonia caused by the protozoan Pneumocystis carinii) and/or tumours, such as Kaposi's sarcoma.
Ordinary social contact with HIV-positive subjects involves no risk of infection. However, high standards of clinical practice are required by all health workers in order to avoid inadvertent infection via blood, blood products, or body fluids from HIV-positive people. Staff who become HIV-positive are expected to declare their status and will be counselled.

Back  -    New Search

AIH n.

see ARTIFICIAL INSEMINATION.

Back  -    New Search

air bed (air) n.

a bed with a mattress whose upper surface is perforated with thousands of holes through which air is forced under pressure, so that the patient is supported on a cushion of air. Air beds are invaluable for the treatment of patients with large areas of burns.

Back  -    New Search

air embolism n.

an air lock that obstructs the outflow of blood from the right ventricle of the heart. Tipping the patient head down, lying on the left side, may move the air lock.

Back  -    New Search

air hunger n.

difficulty in breathing characterized by sighing and gasping. It is caused by anoxia.

Back  -    New Search

air sickness n.

see MOTION SICKNESS.

Back  -    New Search

akathisia (ak--thiz-i) n.

a pattern of involuntary movements induced by antipsychotic drugs, such as phenothiazines. An affected person is driven to restless overactivity, which can be confused with the agitation for which the drug was originally prescribed.

Back  -    New Search

akinesia (ak-in-ee-zi) n.

a loss of normal muscular tonicity or responsiveness. akinetic epilepsy a form of epilepsy in which there is a sudden loss of muscular tonicity, making the patient fall with momentary loss of consciousness. akinetic mutism a state of complete physical unresponsiveness although the patient's eyes remain open and appear to follow movements. It is a consequence of damage to the base of the brain.
—akinetic (a-kin-et-ik) adj.

Back  -    New Search

ala (al-) n. (pl. alae)

(in anatomy) a wing-like structure.

Back  -    New Search

alanine (al--neen) n.

see AMINO ACID.

Back  -    New Search

alanine aminotransferase (ALT) (-mee-noh-trans-fer-ayz) n.

an enzyme involved in the transamination of amino acids. Measurement of ALT in the serum is of use in the diagnosis and study of acute liver disease. The former name, serum glutamic pyruvic transaminase (SGPT), is still widely used.

Back  -    New Search

alastrim (-las-trim) n.

a mild form of smallpox, causing only a sparse rash and low-grade fever. Medical name: variola minor .

Back  -    New Search

Albee's operation (awl-beez) n.

1 an operation to produce ankylosis of the hip. The upper surface of the femur and the corresponding part of the acetabulum are removed and the two exposed surfaces allowed to remain in contact.

2 an operation to immobilize part of the spinal column, using a bone graft from the tibia. [F. H. Albee (1876–1945), US surgeon]
Top

Back  -    New Search

albendazole (al-ben-d-zohl) n.

an an-thelmintic drug used to eliminate roundworms, hookworms, and other worm parasites. It is administered by mouth. Trade name: Eskazole .

Back  -    New Search

Albers-Schönberg disease (al-bers shern-berg) n.

see OSTEOPETROSIS. [H. E. Albers-Schönberg disease (1865–1921), German radiologist]

Back  -    New Search

albinism (al-bin-izm) n.

the inherited absence of pigmentation in the skin, hair, and eyes (see ALBINO).

Back  -    New Search

albino (al-bee-noh) n.

an individual lacking the normal body pigment (melanin). Albinos have white hair and pink skin and eyes, reduced visual acuity, and sensitivity to light (see PHOTOPHOBIA).

Back  -    New Search

albumin (al-bew-min) n.

a protein that is soluble in water and coagulated by heat. serum a. a protein found in blood plasma that is important for the maintenance of plasma volume.

Back  -    New Search

albuminuria (proteinuria) (al-bew-min-yoor-i) n.

the presence of serum albumin, serum globulin, or other serum proteins in the urine, which may be associated with kidney or heart disease. orthostatic a. albuminuria not associated with disease, occurring after strenuous exercise or after a long period of standing.

Back  -    New Search

albumose (al-bew-mohz) n.

a substance, intermediate between albumin and peptones, produced during the digestion of proteins by pepsin and other endopepti-dases (see PEPTIDASE).

Back  -    New Search

alcaptonuria (alkaptonuria) (al-kap-tn-yoor-i) n.

accumulation in the tissues and excretion in the urine of homogentisic acid due to congenital absence of homogentisic acid oxidase, an enzyme essential for the normal breakdown of the amino acids tyrosine and phenylalanine.

Back  -    New Search

alclometazone (al-kloh-met--zohn) n.

a corticosteroid drug administered externally as a cream or ointment to treat inflammatory skin disorders. Trade name: Modrasone .

Back  -    New Search

alcohol (al-k-hol) n.

any of a class of organic compounds formed when a hydroxyl group (-OH) is substituted for a hydrogen atom in a hydrocarbon. ethyl a. (ethanol) the alcohol in alcoholic drinks, produced by the fermentation of sugar by yeast. Formula:
C_2H_5OH
. ‘Pure’ alcohol contains not less than 94.9% by volume of ethyl alcohol. A solution of 70% alcohol can be used as a preservative or antiseptic. See also ALCOHOLISM.
—alcoholic (al-k-hol-ik) adj., n.

Back  -    New Search

alcohol-fast adj.

describing bacteria that have been stained and continue to hold the stain after treatment with alcohol.

Back  -    New Search

Alcoholics Anonymous n.

a voluntary agency of self-help that is organized and operated locally among those with alcoholic dependency.

Back  -    New Search

alcoholism (al-k-hol-izm) n.

the syndrome due to physical dependence on alcohol, such that sudden deprivation may cause withdrawal symptoms – tremor, anxiety, hallucinations, and delusions (see DELIRIUM (TREMENS)). Alcoholism impairs intellectual function, physical skills, memory, and judgment. Heavy consumption of alcohol also causes cardiomyopathy, peripheral neuritis, cirrhosis of the liver, and enteritis.

Back  -    New Search

alcoholuria (al-k-hol-yoor-i) n.

the presence of alcohol in the urine.

Back  -    New Search

alcuronium (al-kewr-oh-nim) n.

a drug causing profound relaxation of voluntary muscles (see MUSCLE RELAXANT). Used during anaesthesia, it is administered by injection. Trade name: Alloferin .

Back  -    New Search

aldesleukin (al-des-loo-kin) n.

a genetically engineered form of interleukin 2 that enhances the function of the immune system. Administered by injection, it has produced encouraging results against certain cancers, including melanomas and kidney-cell cancer. Trade name: Proleukin .

Back  -    New Search

Aldomet (al-d-met) n.

see METHYLDOPA.

Back  -    New Search

aldosterone (al-dos-ter-ohn) n.

a steroid hormone (see CORTICOSTEROID) that is synthesized and released by the adrenal cortex and acts on the kidney to regulate salt (potassium and sodium) and water balance.

Back  -    New Search

aldosteronism (al-dos-t-r-nizm) n.

over-production of aldosterone, causing electrolyte imbalance and raised blood pressure (hypertension). See also CONN'S SYNDROME.

Back  -    New Search

alendronate (-len-dr-nayt) n.

see BIPHOSPHONATES.

Back  -    New Search

Aleppo boil (-lep-oh) n.

see ORIENTAL SORE.

Back  -    New Search

aleukaemic (al-yoo-kee-mik) adj.

describing a stage of leukaemia in which there is no absolute increase in the number of white cells in the blood.

Back  -    New Search

alexia (-leks-i) n.

an acquired inability to read due to disease in the left hemisphere of the brain in a right-handed person. agnostic a. (word blindness) inability to identify letters and words not affecting the patient's ability to write. See also DYSLEXIA.

Back  -    New Search

alfacalcidol (al-f-kal-sid-ol) n.

a synthetic form of vitamin D used to raise blood-calcium levels in osteomalacia and bone disorders caused by kidney disease. It is administered by mouth or by injection. Trade name: One-alpha .

Back  -    New Search

alfentanil hydrochloride (al-fen-t-nil) n.

a narcotic analgesic drug used to relieve severe pain. It is administered by injection. Trade name: Rapifen .

Back  -    New Search

ALG n.

antilymphocyte globulin. See ANTILYMPHOCYTE SERUM.

Back  -    New Search

algesimeter (al-j-sim-it-er) n.

a piece of equipment for determining the sensitivity of the skin to various touch stimuli, especially those causing pain.

Back  -    New Search

-algia suffix

denoting pain.

Back  -    New Search

algid (al-jid) adj.

cold: usually describing the cold clammy skin associated with certain forms of malaria.

Back  -    New Search

alginic acid (al-gin-ik) n.

an antacid drug used to treat heartburn caused by acid reflux into the gullet and hiatus hernia. It is administered by mouth. Trade names: Gastrocote , Gastron .

Back  -    New Search

alienation (ay-li-n-ay-shn) n.

(in psychiatry) 1 the experience that one's thoughts are under the control of somebody else, or that other people participate in one's thinking.

2 insanity.
Top

Back  -    New Search

alimentary canal (ali-ment-er-i) n.

the long passage, extending from the mouth to the anus, through which food passes to be digested and absorbed.

Back  -    New Search

aliquot (al-i-kwot) n.

one of a known number of equal parts of a compound or solution.

Back  -    New Search

alkalaemia (al-k-lee-mi) n.

abnormally high blood alkalinity. See also ALKALOSIS. Compare ACIDAEMIA.

Back  -    New Search

alkali (al-k-ly) n.

a base that is soluble in water. Alkaline solutions turn litmus paper blue. See BASE.

Back  -    New Search

alkaloid (al-k-loid) n.

one of a diverse group of nitrogen-containing substances that are produced by plants and have potent effects on body function. Many alkaloids are important drugs, including morphine, quinine, atropine, and codeine.

Back  -    New Search

alkalosis (al-k-loh-sis) n.

a condition in which the alkalinity of body fluids and tissues is abnormally high. This arises because of a failure of the mechanisms that usually maintain a balance between alkalis and acids in the arterial blood (see ACID-BASE BALANCE).

Back  -    New Search

alkaptonuria n.

see ALCAPTONURIA.

Back  -    New Search

alkylating agent (al-ki-lay-ting) n.

a drug, such as mustine (nitrogen mustard), that disrupts the growth of a malignant tumour by damaging the DNA in the tumour cell nuclei.

Back  -    New Search

allantois (al-n-toh-iss) n.

the membranous sac that develops as an outgrowth of the embryonic hindgut. Its outer (meso-dermal) layer carries blood vessels to the placenta and so forms part of the umbilical cord.
—allantoic adj.

Back  -    New Search

allele (allelomorph) (-leel) n.

one of two or more alternative forms of a gene, only one of which can be present in a chromosome. See also DOMINANT, RECESSIVE.
—allelic adj.

Back  -    New Search

allelomorph (-leel-oh-morf) n.

see ALLELE.

Back  -    New Search

allergen (al-er-jn) n.

any antigen that causes allergy in a hypersensitive person.
—allergenic adj.

Back  -    New Search

allergy (al-er-ji) n.

a disorder in which the body becomes hypersensitive to particular antigens (called allergens), which provoke characteristic symptoms whenever they are subsequently encountered. Different allergies afflict different tissues and may have either local or general effects, varying from asthma and hay fever to severe dermatitis or gastroenteritis or extremely serious shock (see ANAPHYLAXIS).
—allergic adj.

Back  -    New Search

allocheiria (al-oh-keer-i) n.

a condition in which the sensation aroused by a stimulus applied to one side of the body is referred to the opposite side.

Back  -    New Search

allodynia (al-oh-dy-ni) n.

extreme tenderness of the skin. It results from nerve damage causing hypersensitivity of the pain receptors in that area, such as occurs in shingles (postherpetic neuralgia – see HERPES).

Back  -    New Search

allogeneic (al-oh-j-nay-ik) adj.

describing grafted tissue derived from a donor of the same species as the recipient but with different histocompatibility.

Back  -    New Search

allograft (al-oh-grahft) n.

see HOMOGRAFT.

Back  -    New Search

allopathy (-lop--thi) n.

(in homeopathic medicine) the orthodox system of medicine, in which the use of drugs is directed to producing effects in the body that will directly oppose and so alleviate the symptoms of a disease. Compare HOMEOPATHY.

Back  -    New Search

allopurinol (al-oh-pewr-i-nol) n.

a drug administered by mouth in the treatment of chronic gout. It acts by reducing the level of uric acid in tissues and blood. Trade names: Hamarin , Zyloric .

Back  -    New Search

all-or-none law n.

the principle that tissue, such as nerve fibres, can produce only one of two reactions to a stimulus. Regardless of the intensity of the stimulus, such tissue will show either a total response or no response at all.

Back  -    New Search

allylestrenol (allyloestrenol) (al-il-eess-tr-nol) n.

a synthetic female sex hormone (see PROGESTOGEN) administered by mouth in the treatment of abnormal bleeding from the uterus. Trade name: Gestanin .

Back  -    New Search

alopecia (baldness) (al--pee-shi) n.

absence of hair from areas where it normally grows. a. areata a condition characterized by bald patches that may regrow; it is an example of an organ-specific autoimmune disease. a. totalis total hair loss, due to an autoimmune condition. androgenetic a. hair loss in women, which is associated with increasing age. scarring (or cicatricial ) a. alopecia in which the hair does not regrow, as occurs in lichen planus and discoid lupus erythematosus.

Back  -    New Search

aloxiprin (-loks-i-prin) n.

a compound made from aluminium oxide and aspirin. Trade name: Palaprin forte .

Back  -    New Search

alpha blocker (alpha-adrenergic blocker) (al-f) n.

a drug that prevents the stimulation of alpha-adrenergic receptors at the nerve endings of the sympathetic nervous system by adrenaline-like hormones: it therefore causes widening of arteries (vasodilatation) and a drop in blood pressure. Alpha blockers include doxazosin, phentolamine, phenoxybenzamine, thymoxamine, indoramin, and prazosin.

Back  -    New Search

alpha cells pl. n.

the cells in the islets of Langerhans that produce glucagon. Compare BETA CELLS.

Back  -    New Search

alpha-fetoprotein (afp) (al-f-fee-toh-proh-teen) n.

a protein that is formed in the liver and yolk sac of the fetus and is present in the amniotic fluid and secondarily in maternal blood. The level of afp is elevated in spina bifida, twin and triplet pregnancies, and certain other conditions and decreased in Down's syndrome. This can be detected by a maternal blood test performed between the 16th and 18th weeks of pregnancy to aid prenatal diagnosis of these conditions.

Back  -    New Search

Alport's syndrome (awl-ports) n.

a hereditary disease that causes nephritis accompanied by deafness. Affected males usually develop end-stage renal failure and, unless treated with a kidney transplant, die before the age of 40. Females have a better prognosis. [A. C. Alport (1880–1959), South African physician]

Back  -    New Search

alprazolam n.

a tranquillizer of the benzodiazepine class used to relieve anxiety and as a sedative. It is administered by mouth. Trade name: Xanax .

Back  -    New Search

alprostadil (al-pros-t-dil) n.

a prostaglandin drug administered by infusion to improve lung blood flow in newborn babies with congenital heart defects who are awaiting surgery and by injection into the corpora cavernosa of the penis to treat erectile impotence in men. Trade names: Prostin VR , Caverject .

Back  -    New Search

ALS n.

1 see ANTILYMPHOCYTE SERUM.

2 amyotrophic lateral sclerosis. See MOTOR NEURONE DISEASE.
Top

Back  -    New Search

ALT n.

see ALANINE AMINOTRANSFERASE.

Back  -    New Search

alteplase (al-t-playz) n.

a tissue plasminogen activator made by genetic engineering. Administered by injection, it is used to dissolve blood clots (see FIBRINO-LYTIC), especially in the coronary arteries of the heart. Trade name: Actilyse .

Back  -    New Search

alternative medicine (complementary medicine, fringe medicine) (awl-ter-n-tiv) n.

the various systems of healing, including homeopathy, herbal remedies, hypnosis, and faith healing, that are not regarded as part of orthodox treatment by the medical profession, especially when offered by unregistered practitioners. Most of the treatments are of unproven benefit but are tried by sufferers of chronic or incurable conditions when orthodox treatment has failed. Many alternative therapies are ridiculed by the medical profession, but acupuncture, osteopathy, and certain others are now generally accepted to be of value in some circumstances. See also CHIROPRACTIC, HOLISTIC, NATUROPATHY.

Back  -    New Search

altitude sickness (mountain sickness) (al-ti-tewd) n.

the condition that results from unaccustomed exposure to a high altitude (4500 m or more above sea level). Reduced atmospheric pressure and shortage of oxygen cause deep rapid breathing, which lowers the concentration of carbon dioxide in the blood.

Back  -    New Search

aluminium hydroxide (al-yoo-min-im) n.

a safe slow-acting antacid and laxative. It is administered by mouth as a gel in the treatment of indigestion, gastric and duodenal ulcers, and reflux oesophagitis. Trade name: Aludrox .

Back  -    New Search

alveolitis (al-vee-oh-ly-tis) n.

inflammation of an alveolus or alveoli. Chronic inflammation of the walls of the alveoli of the lungs is usually caused by inhaled organic dusts (external allergic a. ; see BIRD-FANCIER'S LUNG, FARMER'S LUNG) but may occur spontaneously (cryptogenic fibrosing a. ).

Back  -    New Search

alveolus (al-vee-oh-ls) n. (pl. alveoli)

1 (in the lung) a blind-ended air sac of microscopic size.

2 the part of the upper or lower jawbone that supports the roots of the teeth (see also MANDIBLE, MAXILLA).
Top

3 the sac of a racemose gland (see also ACINUS).
Top

4 any other small cavity, depression, or sac.
Top

—alveolar adj.

Back  -    New Search

alverine citrate (al-v-reen) n.

a bulking agent and antispasmodic drug used to treat the irritable bowel syndrome and other colonic disorders. It is administered by mouth. Trade names: Alvercol , Spasmonal .

Back  -    New Search

Alzheimer's disease (alts-hy-merz) n.

a progressive form of dementia occurring in middle age or later, characterized by loss of short-term memory, deterioration in both behaviour and intellectual performance, and slowness of thought. It is associated with damage to cholinergic pathways in the brain and the presence of excess amyloid protein in brain tissue. [A. Alzheimer (1864–1915), German physician]

Back  -    New Search

amalgam (-mal-gm) n.

any of a group of alloys containing mercury. In dentistry amalgam fillings are made by mixing a silver-tin alloy with mercury in a machine known as an amalgamator .

Back  -    New Search

amantadine (-man-t-deen) n.

an antiviral drug used in the treatment of influenza infections. Because it stimulates an increase in the concentration of dopamine in the brain, it is also used to treat parkinsonism. Trade name: Symmetrel .

Back  -    New Search

amaurosis (am-aw-roh-sis) n.

partial or complete blindness. a. fugax a condition in which loss of vision is transient.
—amaurotic (am-aw-rot-ik) adj.

Back  -    New Search

amaurotic familial idiocy n.

see TAY-SACHS DISEASE.

Back  -    New Search

ambivalence (am-biv-lns) n.

(in psychology) the condition of holding opposite feelings (such as love and hate) for the same person or object.

Back  -    New Search

amblyopia (am-blee-oh-pi) n.

poor sight, not due to any detectable disease of the eyeball or visual system. a. ex anopsia a condition in which factors such as squint (see STRABISMUS), cataract, and other abnormalities of the optics of the eye (see REFRACTION) impair its normal use in early childhood by preventing the formation of a clear image on the retina.

Back  -    New Search

amblyoscope (orthoptoscope, synoptophore) (am-blee--skohp) n.

an instrument for measuring the angle of a squint and assessing the degree to which a person uses both eyes together.

Back  -    New Search

ambulant (am-bew-lnt) adj.

able to walk.

Back  -    New Search

ambulatory (am-bew-layt-er-i) adj.

relating to walking. a. treatment treatment that enables or encourages a patient to remain on his feet.

Back  -    New Search

AMD n.

age-related macular degeneration. See MACULAR DEGENERATION.

Back  -    New Search

amelia (-mee-li) n.

congenital total absence of the arms or legs due to a developmental defect. It is one of the fetal abnormalities induced by the drug thalidomide taken early in pregnancy. See also PHOCOMELIA.

Back  -    New Search

amelioration (-mee-li-er-ay-shn) n.

general improvement in the condition of a patient; reduction in severity of the symptoms of a disease.

Back  -    New Search

ameloblastoma (-mee-loh-blas-toh-m) n.

a locally malignant tumour of the jaw that develops from enamel-forming cells (ameloblasts ) but does not contain enamel.

Back  -    New Search

amenorrhoea (am-en--ree-) n.

the absence or stopping of the menstrual periods. primary a. the nonappearance of menstrual periods at puberty. This may be due to absence of the uterus or ovaries, a genetic disorder, or hormonal imbalance. secondary a. the stopping of menstrual periods after establishment at puberty, for reasons such as pituitary or thyroid hormone deficiency or anorexia nervosa.

Back  -    New Search

amentia (-men-sh) n.

failure of development of the intellectual faculties. See MENTAL RETARDATION.

Back  -    New Search

amethocaine (-meth--kayn) n.

a potent local anaesthetic. It is applied to skin or mucous membranes for eye, ear, nose and throat surgery, but it has also been employed for spinal anaesthesia.

Back  -    New Search

ametropia (am--troh-pi) n.

any abnormality of refraction of the eye, resulting in blurring of the image formed on the retina. See ASTIGMATISM, HYPERMETROPIA, MYOPIA.

Back  -    New Search

amiloride (-mil--ryd) n.

a potassium-sparing diuretic that causes the increased excretion of sodium and chloride; it is often combined with a thiazide diuretic to reduce the potassium loss that occurs with these drugs. Trade name: Midamor .

Back  -    New Search

amino acid (-mee-noh) n.

an organic compound that contains an amino group (-NH_2) and a carboxyl group (-COOH). Amino acids are fundamental constituents of all proteins (see table). Some can be synthesized by the body; others (see ESSENTIAL AMINO ACID) must be obtained from protein in the diet.

Amino acid

Abbreviation

Amino acid

Abbreviation

alanine

ala

leucine

leu

arginine

arg

lysine

lys

asparagine

asn

methionine

met

aspartic acid

asp

phenylalanine

phe

cysteine

cys

proline

pro

glutamic acid

glu

serine

ser

glutamine

gln

threonine

thr

glycine

gly

tryptophan

trp

histidine

his

tyrosine

tyr

isoleucine

ile

valine

val

an essential amino acid

The amino acids occurring in proteins

Back  -    New Search

aminobenzoic acid (-mee-noh-ben-zoh-ik) n.

see PARA-AMINOBENZOIC ACID.

Back  -    New Search

aminoglutethimide (-mee-noh-gloo-teth-i-myd) n.

a drug used in the treatment of advanced breast cancer. It inhibits synthesis of adrenal steroids (medical adrenalectomy) and is administered by mouth, usually with corticosteroid replacement therapy. Trade name: Orimeten .

Back  -    New Search

aminoglycosides (-mee-noh-gly-koh-sydz) pl. n.

a group of antibiotics active against a wide range of bacteria. Included in the group are gen-tamicin, kanamycin, neomycin, and streptomycin. Because of their toxicity, they are used only when less toxic antibacterials are ineffective or contraindicated. They are usually administered by injection.

Back  -    New Search

aminopeptidase (-mee-noh-pep-ti-dayz) n.

any one of several enzymes in the intestine that cause the breakdown of a peptide, removing an amino acid.

Back  -    New Search

aminophylline (ami-nof-il-een) n.

a drug that relaxes smooth muscle and stimulates respiration. Administered by mouth or in suppositories, it is used in the treatment of asthma and emphysema, to dilate the coronary arteries in angina pectoris, and as a diuretic. See also THEOPHYLLINE. Trade name: Pecram .

Back  -    New Search

aminosalicylic acid (-mee-noh-sali-sil-ik) n.

see PARA-AMINOSALICYLIC ACID.

Back  -    New Search

amiodarone (ami-oh-d-rohn) n.

an antiarrhythmic drug used to control a variety of abnormal heart rhythms, including atrial fibrillation and abnormally rapid heartbeat. It is administered by mouth or by injection. Trade name: Cordarone X.

Back  -    New Search

amitosis (ami-toh-sis) n.

division of the nucleus of a cell by a process, not involving mitosis, in which the nucleus is constricted into two.

Back  -    New Search

amitriptyline (ami-trip-til-een) n.

a tri-cyclic antidepressant drug that has a mild tranquillizing action. Trade names: Elavil , Tryptizol .

Back  -    New Search

amlodipine (am-loh-dy-peen) n.

a calcium antagonist used to treat angina pectoris. It is administered by mouth. Trade name: Istin .

Back  -    New Search

ammonia (-moh-ni) n.

a colourless gas with a pungent odour that can be cooled and compressed to form a liquid. Ammonium salts are used as astringents, diuretics, and expectorants and ammonia itself (in very dilute form) is used as a reflex stimulant. Formula:
NH_3
.

Back  -    New Search

amnesia (am-nee-zi) n.

total or partial loss of memory following physical injury, disease, drugs, or psychological trauma. anterograde a. loss of memory for events following the trauma. retrograde a. loss of memory for events preceding the trauma.

Back  -    New Search

amnihook (am-ni-huuk) n.

a small plastic hooked instrument for performing amniotomy. The hook is introduced through the cervix.

Back  -    New Search

amniocentesis (am-ni-oh-sen-tee-sis) n.

withdrawal of a sample of amniotic fluid surrounding an embryo in the uterus, by means of a syringe inserted through the abdominal wall, to enable prenatal diagnosis of chromosomal abnormalities (such as Down's syndrome) and metabolic and other congenital disorders (such as spina bifida).

Back  -    New Search

amnion (am-ni-n) n.

the membrane that forms initially over the dorsal part of the embryo but soon expands to enclose it completely within the amniotic cavity.
—amniotic (am-ni-ot-ik) adj.

Back  -    New Search

amnioscopy (am-ni-oss-k-pi) n.

examination of the inside of the amniotic sac by means of an instrument (amnioscope ) that is passed through the abdominal wall. cervical a. examination of the amniotic sac through the cervix (neck) of the uterus.

Back  -    New Search

amniotic cavity n.

the fluid-filled cavity between the embryo and the amnion. See also AMNIOTIC FLUID.

Back  -    New Search

amniotic fluid n.

the fluid contained within the amniotic cavity. It surrounds the growing fetus, protecting it from external pressure. See also AMNIOCENTESIS.

Back  -    New Search

amniotomy (artificial rupture of membranes, ARM) (am-ni-ot-mi) n.

a method of surgically inducing labour by puncturing the amnion surrounding the baby in the uterus using an amnihook or similar instrument.

Back  -    New Search

amodiaquine (am-oh-dy--kwin) n.

an antimalarial drug with effects and uses similar to those of chloroquine.

Back  -    New Search

amoeba (-mee-b) n. (pl. amoebae)

any protozoan of jelly-like consistency and irregular and constantly changing shape. Some amoebae cause disease in man (see ENTAMOEBA).
—amoebic adj. —amoeboid adj.

Back  -    New Search

amoebiasis (ami-by--sis) n.

see DYSENTERY.

Back  -    New Search

amoebicide (-mee-bi-syd) n.

an agent that kills amoebae.

Back  -    New Search

amorolfine (am-oh-rol-feen) n.

an antifungal drug used to treat ringworm, candidosis, and other fungal infections of the skin and nails. It is applied externally as a cream or nail lacquer. Trade name: Loceryl .

Back  -    New Search

amoxapine (-moks--peen) n.

a tricyclic antidepressant drug similar to imipramine. It is administered by mouth. Trade name: Asendis .

Back  -    New Search

amoxicillin (-mok-si-sil-in) n.

an antibiotic used to treat infections caused by a wide range of bacteria and other microorganisms. It is administered by mouth; sensitivity to penicillin prohibits its use. Trade name: Amoxil .

Back  -    New Search

AMP (adenosine monophosphate) n.

a compound containing adenine, ribose, and one phosphate group. AMP occurs in cells and is involved in processes requiring the transfer of energy (see ATP).

Back  -    New Search

ampere (am-pair) n.

the basic SI unit of electric current. It is equal to the current flowing through a conductor of resistance 1 ohm when a potential difference of 1 volt is applied between its ends. Symbol: A.

Back  -    New Search

amphetamine (am-fet-min) n.

a sympathomimetic drug that has a marked stimulant action on the central nervous system. Administered by mouth, it has been used in the treatment of narcolepsy, mild depressive neuroses, and obesity, but the chief indication is for the treatment of attention deficit disorder in children. Tolerance to amphetamine develops rapidly, and prolonged use may lead to dependence.

Back  -    New Search

amphiarthrosis (am-fi-arth-roh-sis) n.

a slightly movable joint in which the bony surfaces are separated by fibrocartilage (see SYMPHYSIS) or hyaline cartilage (see SYN-CHONDROSIS).

Back  -    New Search

amphoric breath sounds (am-fo-rik) pl. n.

see CAVERNOUS BREATH SOUNDS.

Back  -    New Search

amphotericin (am-foh-te-ri-sin) n.

an antibiotic used to treat deep-seated fungal infections. It can be administered by mouth, but is usually given by intravenous injection. Trade names: Fungilin , Fungizone .

Back  -    New Search

ampicillin (am-pi-sil-in) n.

an antibiotic administered by mouth or injection in the treatment of a variety of infections, including those of the urinary, respiratory, biliary, and intestinal tracts. Trade names: Amfipen , Penbritin .

Back  -    New Search

ampoule (ampule) (am-pool) n.

a sealed glass or plastic capsule containing one dose of a drug in the form of a sterile solution for injection.

Back  -    New Search

ampulla (am-puul-) n. (pl. ampullae)

an enlarged or dilated ending of a tube or canal. a. of Vater the dilated part of the common bile duct where it is joined by the pancreatic duct. [A. Vater (1684–1751), German anatomist]

Back  -    New Search

amputation (am-pew-tay-shn) n.

the removal of a limb, part of a limb, or any other portion of the body (such as a breast).

Back  -    New Search

amsacrine (am-s-kreen) n.

a cytotoxic drug administered by injection to treat various forms of cancer. Trade name: Amsidine .

Back  -    New Search

amylase (am-i-layz) n.

an enzyme that occurs in saliva and pancreatic juice and aids the digestion of starch, which it breaks down into glucose, maltose, and dextrins.

Back  -    New Search

amyl nitrite (am-il) n.

a drug that relaxes smooth muscle, especially that of blood vessels. Given by inhalation, amyl nitrite is used mainly in the treatment of angina pectoris.

Back  -    New Search

amylobarbitone (ami-loh-bar-bi-tohn) n.

an intermediate-acting barbiturate. Prolonged use may lead to dependence and overdosage has serious toxic effects (see BARBITURISM). Trade name: Amytal .

Back  -    New Search

amyloid (am-i-loid) n.

a glycoprotein, resembling starch, that is deposited in the internal organs in amyloidosis. ß-amyloid protein has been found in the brains of Alzheimer's patients.

Back  -    New Search

amyloidosis (ami-loid-oh-sis) n.

infiltration of the liver, kidneys, spleen, and other tissues with amyloid. primary a. amyloidosis without any apparent cause. secondary a. a late complication of such chronic infections as tuberculosis or leprosy.

Back  -    New Search

amylopectin (ami-loh-pek-tin) n.

see STARCH.

Back  -    New Search

amylopsin (ami-lop-sin) n.

an amylase found in the pancreatic juice.

Back  -    New Search

amylose (am-i-lohz) n.

see STARCH.

Back  -    New Search

amyotonia congenita (floppy baby syndrome) (ay-my--toh-ni kon-jen-it) n.

a former diagnosis for various conditions, present at birth, in which the baby's muscles are weak and floppy (i.e. hypotonic). The term is becoming obsolete as more specific diagnoses are discovered to explain the cause of floppiness in babies.

Back  -    New Search

amyotrophy (ami-ot-rfi) n.

a progressive loss of muscle bulk associated with weakness, caused by disease of the nerve that supplies the affected muscle.

Back  -    New Search

an- prefix.

see A-.

Back  -    New Search

anabolic (an-bol-ik) adj.

promoting tissue growth by increasing the metabolic processes that are involved in protein synthesis. Anabolic agents are usually synthetic male sex hormones (see ANDROGEN).

Back  -    New Search

anabolism (-nab-l-izm) n.

the synthesis of complex molecules, such as proteins and fats, from simpler ones by living organisms. See also ANABOLIC, METABOLISM.

Back  -    New Search

anacidity (an-sid-iti) n.

a deficiency or abnormal absence of acid in the body fluids.

Back  -    New Search

anacrotism (n-ak-rt-izm) n.

the condition in which there is an abnormal curve in the ascending line of a pulse tracing. It may be seen in cases of aortic stenosis.
—anacrotic adj.

Back  -    New Search

anaemia (-nee-mi) n.

a reduction in the quantity of the oxygen-carrying pigment haemoglobin in the blood. The main symptoms are excessive tiredness and fatigability, breathlessness on exertion, pallor, and poor resistance to infection. The many causes of anaemia include loss of blood (haemorrhagic a. ); lack of iron (iron-deficiency a. ); the increased destruction of red blood cells (haemolytic a. ); and the impaired production of red blood cells (see APLASTIC ANAEMIA; LEUKAEMIA; PERNICIOUS (ANAEMIA)). Anaemias can be classified on the basis of the size of the red cells, which may be large (macrocytic a. ), small (microcytic a. ), or normal-sized (normo-cytic a. ).
—anaemic adj.

Back  -    New Search

anaerobe (an-air-rohb) n.

any organism, especially a microbe, that is able to live and grow in the absence of free oxygen. Compare AEROBE.
—anaerobic (an-air-roh-bik) adj.

Back  -    New Search

anaerobic respiration n.

a type of cellular respiration in which foodstuffs (usually carbohydrates) are never completely oxidized because molecular oxygen is not used.

Back  -    New Search

anaesthesia (anis-theez-i) n.

loss of feeling or sensation in a part or all of the body, especially when induced by drugs. general a. total unconsciousness, usually achieved by administering a combination of injections and gases. local a. loss of feeling in a limited area of the body, induced for minor operations, particularly many dental procedures. It may be achieved by injections of substances such as lignocaine close to a local nerve, which deadens the tissues supplied by that nerve. regional a. anaesthesia (usually of a limb) achieved by encircling local anaesthetic solutions, used in situations where general anaesthesia is not appropriate. See also SPINAL ANAESTHESIA.

Back  -    New Search

anaesthetic (anis-thet-ik)

1 n. an agent that reduces or abolishes sensation. general a. an anaesthetic, such as halothane, that affects the whole body. local a. an anaesthetic, such as lignocaine, that affects a particular area or region of the body.

2 adj. reducing or abolishing sensation.
Top

Back  -    New Search

anaesthetist (n-ees-tht-ist) n.

a medically qualified doctor who administers an anaesthetic to induce unconsciousness in a patient before a surgical operation.

Back  -    New Search

anagen (an--jn) n.

the growth phase of a hair follicle, lasting two to three years. It is followed by a transitional stage, called catagen , and then a resting phase, telogen , each of which lasts for about two weeks. On average about 85% of hairs are in anagen and hence growing actively.

Back  -    New Search

anal (ay-nl) adj.

of, relating to, or affecting the anus. a. canal the terminal portion of the large intestine, which is surrounded by the muscles of defecation (a. sphincters ). The canal ends on the surface at the anal orifice (see ANUS). a. fissure see FISSURE.

Back  -    New Search

analeptic (an-lep-tik) n.

a drug that restores consciousness to a patient in a coma or faint. Analeptics stimulate the central nervous system to counteract the effects of large doses of narcotic drugs.

Back  -    New Search

analgesia (an-l-jeez-l) n.

reduced sensibility to pain, without loss of consciousness and without the sense of touch necessarily being affected.

Back  -    New Search

analgesic (an-l-jee-sik)

1 n. a drug that relieves pain. Aspirin and paracetamol are mild analgesics; morphine and pethidine are more potent. See also NARCOTIC.

2 adj. relieving pain.
Top

Back  -    New Search

analogous (-nal--gs) adj.

describing organs or parts that have similar functions in different organisms although they do not have the same evolutionary origin or development. Compare HOMOLOGOUS.

Back  -    New Search

analogue (an--log) n.

a drug that differs in minor ways in molecular structure from its parent compound. Useful analogues of existing drugs are either more potent or cause fewer side-effects. Carboplatin, for example, is a less toxic analogue of cisplatin. See also LHRH ANALOGUE.

Back  -    New Search

analysis (-nal-isis) n.

(in psychology) any means of understanding complex mental processes or experiences. See also PSYCHOANALYSIS.

Back  -    New Search

analyst (an--list) n.

a person who performs analysis.

Back  -    New Search

anaphase (an--fayz) n.

the third stage of mitosis and of each division of meiosis.

Back  -    New Search

anaphylaxis (an-fil-aks-is) n.

an abnormal reaction to a particular antigen, e.g. a localized allergic attack. anaphylactic shock an extreme and generalized allergic reaction in which widespread histamine release causes swelling (oedema), constriction of the bronchioles, heart failure, circulatory collapse, and sometimes death.
—anaphylactic adj.

Back  -    New Search

anaplasia (an-play-zi) n.

a loss of normal cell characteristics or differentiation. Anaplasia is typical of rapidly growing malignant tumours.

Back  -    New Search

anasarca (an-sar-k) n.

massive swelling of the legs, trunk, and genitalia due to retention of fluid (oedema): found in congestive heart failure and some forms of renal failure.

Back  -    New Search

anastomosis (-nass-t-moh-sis) n.

1 (in anatomy) a communication between two blood vessels without any intervening capillary network. arteriovenous a. a thick-walled blood vessel that connects an arteriole directly with a venule, found in the skin of the lips, nose, ears, hands, and feet.

2 (in surgery) an artificial connection between two tubular organs or parts, especially between two normally separate parts of the intestine (a short circuit). See also SHUNT.
Top

Back  -    New Search

anatomy (-nat-mi) n.

the study of the structure of living organisms. In medicine it refers to the study of the form and gross structure of the various parts of the human body. See also CYTOLOGY, HISTOLOGY, PHYSIOLOGY.
—anatomical (an-tom-i-k'l) adj. —anatomist n.

Back  -    New Search

anconeus (an-koh-nis) n.

a muscle behind the elbow that assists in extending the forearm.

Back  -    New Search

Ancylostoma (Ankylostoma) (an-si-loh-stoh-m) n.

a genus of small parasitic nematodes that inhabit the small intestine (see HOOKWORM). A. duodenale the species that most commonly infests man.

Back  -    New Search

ancylostomiasis (an-si-loh-stoh-my-sis) n.

an infestation of the small intestine by the parasitic hookworm Ancylostoma duodenale. See HOOKWORM (DISEASE).

Back  -    New Search

ANDI (an-di) n.

an acronym for abnormal development and involution, used to tabulate benign disorders of the breast.

Back  -    New Search

andr- (andro-) prefix

denoting man or the male sex.

Back  -    New Search

androgen (an-dr-jn) n.

one of a group of steroid hormones, including testosterone and androsterone, that stimulate the development of male sex organs and male secondary sexual characteristics. The principal source of these hormones is the testis but they are also secreted by the adrenal cortex and ovaries in small amounts. In women excessive production of androgens gives rise to masculinization. Naturally occurring and synthetic androgens are used in replacement therapy, as anabolic agents, and in the treatment of breast cancer.
—androgenic adj.

Back  -    New Search

andrology (an-drol-ji) n.

1 the study of male infertility and impotence. It includes seminal analysis and other investigation procedures to determine the causes of infertility, which determine the treatment undertaken.

2 the study of androgen production and the relationship of plasma androgen to androgen action.
Top

—andrologist n.

Back  -    New Search

androsterone (an-drost-er-ohn) n.

a steroid hormone (see ANDROGEN) that is synthesized and released by the testes and is responsible for controlling male sexual development.

Back  -    New Search

anencephaly (an-en-sef-li) n.

partial or complete absence of the bones of the rear of the skull and of the cerebral hemispheres of the brain. It occurs as a developmental defect and most affected infants are stillborn; if born live they do not survive for more than a few hours. See also ALPHA-FETOPROTEIN.
—anencephalous adj.

Back  -    New Search

anergy (an-er-ji) n.

1 lack of response to a specific antigen or allergen.

2 lack of energy.
Top

—anergic adj.

Back  -    New Search

aneurine (vitamin B_1) (an-yoor-in) n.

see VITAMIN B.

Back  -    New Search

aneurysm (an-yoor-izm) n.

a balloon-like swelling in the wall of an artery, due to disease or congenital deficiency. aortic a. an aneurysm anywhere in the aorta. It may be a dissecting aneurysm. arterio-venous a. a direct communication between an artery and vein, without an intervening capillary bed. berry a. a small saccular aneurysm commonly affecting branches of the circle of Willis in the brain. Usually associated with congenital weakness of the vessels, they are a cause of cerebral haemorrhage in young adults. Charcot-Bouchard a. a small aneurysm found within the brain of elderly and hypertensive subjects. Such aneurysms may rupture, causing cerebral haemorrhage. dissecting a. a condition in which a tear occurs in the lining of the aorta, which allows blood to enter the wall and track along (dissect) the muscular coat. A dissecting aneurysm may rupture or it may compress the blood vessels arising from the aorta and produce infarction (localized necrosis) in the organs they supply. ventricular a. a condition that may develop in the wall of the left ventricle after myocardial infarction. Heart failure may result or thrombosis within the aneurysm may act as a source of embolism.
—aneurysmal adj.

Back  -    New Search

angi- (angio-) prefix

denoting blood or lymph vessels.

Back  -    New Search

angiectasis (an-ji-ek-t-sis) n.

abnormal dilation of blood vessels.

Back  -    New Search

angiitis (vasculitis) (an-ji-I-tis) n.

a patchy inflammation of the walls of small blood vessels.

Back  -    New Search

angina (an-jy-n) n.

a sense of suffocation or suffocating pain. a. pectoris pain in the centre of the chest, which is induced by exercise and relieved by rest and may spread to the jaws and arms. Angina pectoris occurs when the demand for blood by the heart exceeds the supply of the coronary arteries and it usually results from coronary artery atheroma. It may be prevented or relieved by such drugs as glyceryl trinitrate and propranolol or by surgery (see ANGIOPLASTY, CORONARY BYPASS GRAFT). See also LUDWIG'S ANGINA.

Back  -    New Search

angiocardiography (an-ji-oh-kar-di-og-rfi) n.

X-ray examination of the chambers of the heart after introducing a radiopaque contrast medium into the blood in the heart. A recording is made by a rapid-sequence digital subtraction technique, which can be viewed subsequently via a TV monitor. The recording is called an angiocardiogram .

Back  -    New Search

angiodysplasia (an-ji-oh-dis-play-zi) n.

an abnormal collection of small blood vessels in the wall of the bowel, which may bleed.

Back  -    New Search

angiogenesis (an-ji-oh-jen-i-sis) n.

the formation of new blood vessels. This process is essential for the development of a tumour and is promoted by growth factors.

Back  -    New Search

angiography (an-ji-og-rfi) n.

X-ray examination of blood vessels. A contrast medium is injected into the artery and a rapid series of X-ray recordings (angiograms ) is made (see ARTERIOGRAPHY). digital subtraction a. a sophisticated technique for visualizing blood-vessel anatomy and blood supply to an organ in which a digitized image of blood vessels taken before the addition of contrast medium is subtracted by computer from the contrast image. fluorescein a. a technique for visualizing blood flow in the retina, in which the dye fluorescein sodium, injected into the bloodstream, causes the retinal blood vessels to fluoresce. indocyanine green a. a technique for visualizing blood flow in the choroid layer of the eye after the injection of the dye indocyanine green.

Back  -    New Search

angiology (an-ji-ol-ji) n.

the branch of medicine concerned with the structure, function, and diseases of blood vessels.

Back  -    New Search

angioma (an-ji-oh-m) n. (pl. angiomata)

a benign tumour composed of blood vessels or lymph vessels. arteriovenous a. (arteriovenous malformation , AVM) a knot of distended blood vessels overlying and compressing the surface of the brain. cherry a. (Campbell de Morgan spot) a small red spot, consisting of a minor vascular malformation, occurring on the trunk in middle-aged and elderly people. See also HAEMANGIOMA, LYMPHANGIOMA.

Back  -    New Search

angio-oedema (angioneurotic oedema) (an-ji-oh-ee-dee-m) n.

see URTICARIA.

Back  -    New Search

angioplasty (an-ji-oh-plasti) n.

surgical repair or reconstruction of narrowed or completely obstructed arteries (rarely veins). balloon a. (percutaneous transluminal a. , PTA) enlargement of the lumen of an artery by means of an inflatable balloon, mounted on the tip of a flexible catheter, under X-ray screening control. coronary a. balloon angioplasty of a section of coronary artery narrowed by atheroma.

Back  -    New Search

angiosarcoma (an-ji-oh-sar-koh-m) n.

a sarcoma arising in the blood vessels.

Back  -    New Search

angiospasm (an-ji-oh-spazm) n.

see RAYNAUD'S DISEASE.

Back  -    New Search

angiotensin (an-ji-oh-ten-sin) n.

either of two peptides. a. I a peptide derived, by the action of renin, from a protein secreted by the liver into the bloodstream. a. II a peptide, formed from angiotensin I by enzyme action, that causes constriction of blood vessels and stimulates the release of vasopressin and aldosterone, which increase blood pressure. See also ACE INHIBITOR.

Back  -    New Search

angstrom (ang-strm) n.

a unit of length equal to one ten millionth of a millimetre (10-10 m), sometimes used to express wavelengths and interatomic distances. Symbol Å.

Back  -    New Search

anhedonia (an-hee-doh-ni) n.

total loss of the feeling of pleasure in acts that normally give pleasure.

Back  -    New Search

anhidrosis (an-hy-droh-sis) n.

the absence of sweating in the presence of an appropriate stimulus for sweating, such as heat, which may accompany disease or occur as a congenital defect. See also HYPOHIDROSIS.

Back  -    New Search

anhidrotic (an-hy-drot-ik)

1 n. any drug that inhibits the secretion of sweat, such as a parasympatholytic drug.

2 adj. inhibiting sweating.
Top

Back  -    New Search

anhydraemia (an-hy-dree-mi) n.

a decrease in the proportion of water, and therefore plasma, in the blood.

Back  -    New Search

anhydrous (an-hy-drs) adj.

containing no water.

Back  -    New Search

aniline (an-il-een) n.

an oily compound obtained from coal tar and widely used in the preparation of dyes.

Back  -    New Search

anion (an-l-n) n.

a negatively charged ion, which moves towards the anode (positive electrode) when an electric current is passed through the solution containing it. Compare CATION. a. gap the difference between the concentrations of cations (positively charged ions) and anions, calculated from the formula (Na+ + K+) - (HCO_3- + Cl-): it is used to estimate the un-accounted-for anions in the blood in cases of metabolic disturbance.

Back  -    New Search

aniridia (ani-rid-i) n.

congenital absence of the iris (of the eye).

Back  -    New Search

anisocytosis (an-l-soh-sy-toh-sis) n.

an excessive variation in size between individual red blood cells.

Back  -    New Search

anisomelia (an-l-soh-mee-li) n.

a difference in size or shape between the arms or the legs.

Back  -    New Search

anisometropia (an-l-soh-m-troh-pi) n.

the condition in which the power of refraction in one eye differs markedly from that in the other.

Back  -    New Search

anistreplase (ani-strep-layz) n.

a fibrinolytic drug consisting of a complex of streptokinase and plasminogen. It is administered by injection in the treatment of coronary thrombosis. Trade name: Eminase .

Back  -    New Search

ankle (an-k'l) n.

1 the hinge joint between the leg and the foot. It consists of the talus (ankle bone), which projects into a socket formed by the lower ends of the tibia and fibula.

2 the whole region of the ankle joint, including the tarsus and the lower parts of the tibia and fibula.
Top

Back  -    New Search

ankyloblepharon (anki-loh-blef-er-on) n.

abnormal fusion (partial or complete) of the upper and lower eyelid margins.

Back  -    New Search

ankylosing spondylitis (anki-loh-zing) n.

see SPONDYLITIS.

Back  -    New Search

ankylosis (anki-loh-sis) n.

fusion of the bones across a joint space, either by bony tissue (bony a. ) or by shortening of connecting fibrous tissue (fibrous a. ).

Back  -    New Search

Ankylostoma (anki-loh-stoh-m) n.

see ANCYLOSTOMA.

Back  -    New Search

annulus (an-yoo-ls) n.

(in anatomy) a circular opening or ring-shaped structure.
—annular adj.

Back  -    New Search

ano- prefix

denoting the anus.

Back  -    New Search

anodyne (an--dyn) n.

any treatment or drug that soothes and eases pain.

Back  -    New Search

anomaly (-nom-li) n.

any deviation from the normal, especially a congenital or developmental defect.
—anomalous adj.

Back  -    New Search

anomia (-noh-mi) n.

1 a form of aphasia in which the patient is unable to give the names of objects, but retains the ability to put words together into speech.

2 absence of respect for laws and established customs, which is a feature of psychopathy and dyssocial personality disorder.
Top

Back  -    New Search

anomie (an-oh-mi) n.

a condition in which a person is no longer able to identify with or relate to others, resulting in apathy, loneliness, and distress.

Back  -    New Search

anonychia (an-nik-i) n.

congenital absence of one or more nails.

Back  -    New Search

Anopheles (-nof-i-leez) n.

a genus of widely distributed mosquitoes. The malarial parasite (see PLASMODIUM) is transmitted to man solely through the bite of female Anopheles mosquitoes.

Back  -    New Search

anophthalmos (an-off-thal-ms) n.

congenital absence of the eye.

Back  -    New Search

anoplasty (ay-noh-plasti) n.

a surgical technique used to repair a weak or injured anal sphincter.

Back  -    New Search

anorchism (an-or-kizm) n.

congenital absence of one or both testes.

Back  -    New Search

anorexia (an-er-eks-i) n.

loss of appetite. a. nervosa a psychological illness, most common in female adolescents, in which the patients starve themselves or use other techniques, such as vomiting or taking laxatives, to induce weight loss. The result is severe loss of weight, often with amenorrhoea, and sometimes even death from starvation. The problem often starts with an obsessive desire to lose weight but the underlying cause of the illness is more complicated. Patients must be persuaded to eat enough to maintain a normal body weight and their emotional disturbance is usually treated with psychotherapy. See also BULIMIA.

Back  -    New Search

anosmia (an-oz-mi) n.

a loss of the sense of smell.

Back  -    New Search

anovular (anovulatory) (an-ov-yoo-ler) adj.

not associated with the development and release of a female germ cell (ovum) in the ovary, as in anovular menstruation .

Back  -    New Search

anoxaemia (an-oks-ee-mi) n.

a condition in which there is less than the normal concentration of oxygen in the blood. See also HYPOXAEMIA.

Back  -    New Search

anoxia (an-oks-i) n.

a condition in which the tissues of the body receive inadequate amounts of oxygen. See also HYPOXIA.
—anoxic adj.

Back  -    New Search

ant- (anti-) prefix

denoting opposed to; counteracting; relieving.

Back  -    New Search

Antabuse (ant--bews) n.

see DISULFIRAM.

Back  -    New Search

antacid (ant-ass-id) n.

a drug, such as sodium bicarbonate, that neutralizes the hydrochloric acid secreted in the digestive juices of the stomach. Antacids are used to relieve discomfort in disorders of the digestive system.

Back  -    New Search

antagonist (an-tag-n-ist) n.

1 a muscle whose action (contraction) opposes that of another muscle (see AGONIST).

2 a drug or other substance with opposite action to that of another drug or natural body chemical.
Top

—antagonism n.

Back  -    New Search

antazoline (ant-az--leen) n.

a short-acting antihistamine drug, given by mouth to relieve the symptoms of allergic reactions. Trade name: Otrivine-Antistin .

Back  -    New Search

ante- prefix

denoting before.

Back  -    New Search

anteflexion (anti-flek-shn) n.

the bending forward of an organ. A mild degree of anteflexion of the uterus is considered to be normal.

Back  -    New Search

ante mortem (an-ti mor-tm) adj.

before death. Compare POST MORTEM.

Back  -    New Search

antenatal (anti-nay-t'l) adj.

of or relating to the period of pregnancy; before birth. a. diagnosis see PRENATAL DIAGNOSIS.

Back  -    New Search

antepartum (anti-par-tm) adj.

occurring before the onset of labour. a. haemorrhage bleeding from the genital tract after the 24th week of pregnancy until the birth of the baby.

Back  -    New Search

anterior (an-teer-i-er) adj.

1 describing or relating to the front (ventral) portion of the body or limbs.

2 describing the front part of any organ. a. chamber the part of the eye between the cornea and lens, which is filled with aqueous humour.
Top

Back  -    New Search

anteversion (anti-ver-shn) n.

the forward inclination of an organ, especially the normal forward inclination of the uterus.

Back  -    New Search

anthelmintic (an-thel-min-tik)

1 n. any drug, such as piperazine, or chemical agent used to destroy parasitic worms (helminths) and/or remove them from the body.

2 adj. having the power to destroy or eliminate helminths.
Top

Back  -    New Search

anthracosis (an-thr-koh-sis) n.

see COALWORKER'S PNEUMOCONIOSIS.

Back  -    New Search

anthracycline (an-thr-sy-kleen) n.

any of numerous antibiotics synthesized or isolated from species of Streptomyces. Doxorubicin is the most important member of this group of compounds, which have wide activity against tumours.

Back  -    New Search

anthrax (an-thraks) n.

an acute infectious disease of farm animals caused by the bacterium Bacillus anthracis. In man the disease attacks either the lungs, causing pneumonia, or the skin, producing severe ulceration (malignant pustule ). Woolsorter's disease is a serious infection of the skin or lungs by B. anthracis, affecting those handling wool or pelts (see OCCUPATIONAL DISEASE). Anthrax can be treated with penicillin or tetracycline.

Back  -    New Search

anthrop- (anthropo-) prefix

denoting the human race.

Back  -    New Search

anti-androgen (anti-an-dr-jn) n.

any one of a group of drugs that block the cellular uptake of testosterone by the prostate gland and are therefore used in the treatment of prostate cancer, which is an androgen-dependent tumour, and various sexual disorders in men. See also CYPROTERONE.

Back  -    New Search

anti-arrhythmic (anti--rith-mik) n.

any of a group of drugs used to correct irregularities in the heartbeat (see ARRHYTHMIA). They include atropine, amiodarone, quinidine, verapamil, disopyramide, and lignocaine.

Back  -    New Search

antibacterial (anti-bak-teer-il) adj.

describing an antibiotic that is active against bacteria.

Back  -    New Search

antibiotic (anti-by-ot-ik) n.

a substance, produced by or derived from a microorganism, that destroys or inhibits the growth of other microorganisms. Antibiotics are used to treat infections caused by organisms that are sensitive to them, usually bacteria or fungi. See also AMINOGLYCOSIDES, ANTIFUNGAL, ANTIVIRAL DRUG, CEPHALOSPORIN, CHLORAMPHENICOL, PENICILLIN, QUINOLONE, STREPTOMYCIN, TETRACYCLINE.

Back  -    New Search

antibody (an-ti-bodi) n.

a special kind of blood protein that is synthesized in lymphoid tissue in response to the presence of a particular antigen and circulates in the plasma to attack the antigen and render it harmless. Antibody formation is the basis of both immunity and allergy; it is also responsible for tissue or organ rejection following transplantation.

Back  -    New Search

anticholinergic (anti-koli-ner-jik) adj.

inhibiting the action of acetylcholine. Parasympatholytic drugs are anticholinergic.

Back  -    New Search

anticholinesterase (anti-koli-nes-ter-ayz) n.

any substance that inhibits the action of cholinesterase and therefore allows acetylcholine to continue transmitting nerve impulses.

Back  -    New Search

anticoagulant (anti-koh-ag-yoo-lnt) n.

an agent, such as heparin or phenindione, that prevents the clotting of blood and is used in the treatment of such conditions as thrombosis and embolism. Incorrect dosage may result in haemorrhage.

Back  -    New Search

anticonvulsant (anti-kn-vul-snt) n.

a drug, such as sodium valproate or phenytoin, that prevents or reduces the severity of seizures in various types of epilepsy. Anticonvulsants are also known as antiepileptic drugs .

Back  -    New Search

anti D n.

the rhesus-factor antibody, formed by rhesus-negative individuals following exposure to rhesus-positive blood. See HAEMOLYTIC DISEASE OF THE NEWBORN.

Back  -    New Search

antidepressant (anti-di-press-nt) n.

a drug that alleviates the symptoms of depression. The most widely prescribed group are the tricyclic antidepressants , such as amitriptyline and imipramine. See also MAO INHIBITOR, SSRI.

Back  -    New Search

antidiuretic hormone (ADH) (anti-dy-yoor-et-ik) n.

see VASOPRESSIN.

Back  -    New Search

antidote (an-ti-doht) n.

a drug that counteracts the effects of a poison.

Back  -    New Search

antiemetic (anti-i-met-ik) n.

a drug that prevents vomiting, used to treat such conditions as motion sickness and vertigo and to counteract nausea and vomiting caused by other drugs.

Back  -    New Search

antiepileptic drug (anti-epi-lep-tik) n.

see ANTICONVULSANT.

Back  -    New Search

antifibrinolytic (anti-fib-rin--lit-ik) adj.

describing an agent that inhibits the dissolution of blood clots (see FIBRINOLYSIS). Antifibrinolytic drugs include aprotinin and tranexamic acid.

Back  -    New Search

antifungal (antimycotic) (anti-fung-l) adj.

describing a drug that kills or inactivates fungi and is used to treat fungal (including yeast) infections. Antifungal drugs include amphotericin, griseofulvin, the imidazoles, nystatin, terbinafine, and tolnaftate.

Back  -    New Search

antigen (an-ti-jn) n.

any substance that the body regards as foreign or potentially dangerous and against which it produces an antibody.
—antigenic adj.

Back  -    New Search

antihaemophilic factor (anti-heem--fil-ik) n.

see HAEMOPHILIA.

Back  -    New Search

antihistamine (anti-hist--meen) n.

a drug that inhibits the action of histamine in the body by blocking the receptors for histamine, of which there are two types: H_1 and H_2. When stimulated by histamine, H_1 receptors may produce such allergic reactions as hay fever, pruritus (itching), and urticaria (nettle rash). Antihistamines that block H_1 receptors (H_1-receptor antagonists), such as acrivastine, astemizole, azatadine, and chlorpheniramine, are used to relieve these conditions. Many H_1-receptor antagonists (see CYCLIZINE, PROMETHAZINE) also have strong antiemetic activity and are used to prevent motion sickness. The most common side-effect of these H_1-receptor antagonists is drowsiness and because of this they are sometimes used to promote sleep. H_2 receptors are found mainly in the stomach, where stimulation by histamine causes secretion of acid gastric juice. H_2-receptor antagonists (see CIMETIDINE, RANITIDINE) block these receptors and so reduce gastric acid secretion; they are used in the treatment of peptic ulcers and gastro-oesophageal reflux disease.

Back  -    New Search

anti-inflammatory (anti-in-flam--t-ri)

1 adj. describing a drug that reduces inflammation. The various groups of anti-inflammatory drugs act against one or more of the mediators that initiate or maintain inflammation. They include antihistamines, the glucocorticoids (see CORTICOSTEROID), and the nonsteroidal anti-inflammatory drugs (see NSAID).

2 n. an anti-inflammatory drug.
Top

Back  -    New Search

antilymphocyte serum (antilympho-cyte globulin, ALS, ALG) (anti-lim-foh-syt) n.

an antiserum containing antibodies that suppress lymphocytic activity. ALS may be given to prevent the immune reaction that causes tissue rejection following transplantation of such organs as kidneys.

Back  -    New Search

antimetabolite (anti-mi-tab--lyt) n.

a drug that interferes with the normal metabolic processes within cells by combining with the enzymes responsible for them. Some drugs used in the treatment of cancer, e.g. fluorouracil, methotrexate, and mercaptopurine, are antimetabolites. Side-effects can be severe, involving blood cell disorders and digestive disturbances. See also CYTOTOXIC DRUG.

Back  -    New Search

antimitotic (anti-my-tot-ik) n.

a drug that inhibits cell division and growth. The drugs used to treat cancer are mainly antimitotics. See also ANTIMETABOLITE, CYTOTOXIC DRUG.

Back  -    New Search

antimycotic (anti-my-kot-ik) adj.

see ANTIFUNGAL.

Back  -    New Search

anti-oestrogen (anti-ees-tr-jn) n.

one of a group of drugs that oppose the action of oestrogen. It includes tamoxifen, which is used in the treatment of breast cancers dependent on oestrogen. Because they stimulate the production of pituitary gon-adotrophins, some anti-oestrogens (e.g. clomiphene) are used to induce or stimulate ovulation in infertility treatment (see SUPEROVULATION). Side-effects of antioestrogens include hot flushes, itching of the vulva, nausea, vomiting, and fluid retention.

Back  -    New Search

antioxidant (anti-oks-i-dnt) n.

a substance capable of neutralizing oxygen free radicals, the highly active and damaging atoms and chemical groups produced by various disease processes and by poisons, radiation, smoking, and other agencies. Antioxidants include vitamin C (ascorbic acid), vitamin E (tocopherols), and beta carotene. Evidence is accumulating that administration of these substances can reduce the incidence of a number of serious diseases.

Back  -    New Search

antiperistalsis (anti-pe-ri-stal-sis) n.

a wave of contraction in the alimentary canal that passes in an oral (i.e. upward or backwards) direction. Compare PERISTALSIS.

Back  -    New Search

antipruritic (anti-proor-it-ik) n.

an agent, such as calamine, that relieves itching (pruritus).

Back  -    New Search

antipsychotic (anti-sy-kot-ik) adj.

describing one of a group of drugs used to treat severe mental disorders (psychoses), including schizophrenia and mania; some are administered in small doses to relieve anxiety. Formerly known as major tranquillizers , antipsychotic drugs include the phenothiazines (e.g. chlorpromazine) and butyrophenones (e.g. flupenthixol). atypical a. one of a group of antipsychotics, including clozapine and risperidone, that are used in treating patients unresponsive to conventional antipsychotics. Side-effects of many antipsychotics at high doses include abnormal involuntary movements.

Back  -    New Search

antipyretic (anti-py-ret-ik) n.

a drug that reduces fever by lowering the body temperature.

Back  -    New Search

antisecretory drug (anti-si-kree-tri) n.

any drug that reduces the normal rate of secretion of a body fluid, usually one that reduces acid secretion into the stomach. Such drugs include anticholinergic drugs (see PARASYMPATHOLYTIC), H_2 antagonists (see ANTIHISTAMINE), and proton-pump inhibitors.

Back  -    New Search

antisepsis (anti-sep-sis) n.

the elimination of bacteria, fungi, viruses, and other microorganisms that cause disease by the use of chemical or physical methods.

Back  -    New Search

antiseptic (anti-sep-tik) n.

a chemical, such as hexamine, that destroys or inhibits the growth of disease-causing bacteria and other microorganisms. Antiseptics are used externally to cleanse wounds and internally to treat infections of the intestine and bladder.

Back  -    New Search

antiserum (anti-seer-m) n. (pl. antisera)

a serum that contains antibodies against antigens of a particular kind; it may be injected to treat, or give temporary protection against, specific diseases. Antisera are prepared in large quantities in such animals as horses.

Back  -    New Search

antisocial (anti-soh-shl) adj.

contrary to the accepted standards of behaviour in society.

Back  -    New Search

antispasmodic (anti-spaz-mod-ik) n.

a drug that relieves spasm of smooth muscle. See SPASMOLYTIC. Compare ANTISPASTIC.

Back  -    New Search

antispastic (anti-spas-tik) n.

a drug that relieves spasm of skeletal muscle. See also MUSCLE RELAXANT. Compare ANTISPASMODIC.

Back  -    New Search

antistatic (anti-stat-ik) adj.

preventing the accumulation of static electricity.

Back  -    New Search

antithrombin (anti-throm-bin) n.

a substance or effect that inhibits the action of thrombin in the circulation, preventing unwanted clotting.

Back  -    New Search

antitoxin (anti-toks-in) n.

an antibody produced by the body to counteract a toxin formed by invading bacteria or from any other source.

Back  -    New Search

antitragus (anti-tray-gs) n.

a small projection of cartilage above the lobe of the ear, opposite the tragus. See PINNA.

Back  -    New Search

antitussive (anti-tuss-iv) n.

a drug, such as pholcodine, that suppresses coughing.

Back  -    New Search

antivenene (antivenin) (anti-ven-een) n.

an antiserum containing antibodies against specific poisons in the venom of such an animal as a snake, spider, or scorpion.

Back  -    New Search

antiviral drug (anti-vy-rl) n.

a drug effective against viruses that cause disease. Antiviral drugs include acyclovir, ganci-clovir, vidarabine, idoxuridine, foscarnet, zidovudine, amantadine, and ribavirin.

Back  -    New Search

antrectomy (an-trek-tmi) n.

1 surgical removal of the bony walls of an antrum. see ANTROSTOMY.

2 a surgical operation in which a part of the stomach (the antrum) is removed, used in the treatment of some peptic ulcers.
Top

Back  -    New Search

antroscopy (an-tros-kpi) n.

inspection of the inside of the maxillary sinus (see PARANASAL SINUSES) using an endoscope (called an antroscope ).

Back  -    New Search

antrostomy (an-trost-mi) n.

a surgical operation to produce an artificial opening to an antrum in a bone, so providing drainage for any fluid. The operation is sometimes carried out to treat infection of the paranasal sinuses.

Back  -    New Search

antrum (an-trm) n.

1 a cavity, especially a cavity in a bone. a. of Highmore the maxillary sinus (see PARANASAL SINUSES). [N. Highmore (1613–85), English physician] mastoid (or tympanic ) a. the space connecting the air cells of the mastoid process with the chamber of the inner ear. 2. the part of the stomach adjoining the pylorus.

Back  -    New Search

anuria (-newr-i) n.

failure of the kidneys to produce urine.

Back  -    New Search

anus (ay-ns) n.

the opening at the lower end of the alimentary canal, through which the faeces are discharged. It opens out from the anal canal and is guarded by two sphincters.
—anal adj.

Back  -    New Search

anvil (an-vil) n.

(in anatomy) see INCUS.

Back  -    New Search

anxiety (ang-zy-iti) n.

generalized pervasive fear. a. disorder any one of a group of mental or behavioural disorders in which anxiety is the most prominent feature. see GENERALIZED ANXIETY DISORDER, NEUROSIS, PANIC DISORDER, POST-TRAUMATIC STRESS DISORDER. a. state a condition in which anxiety dominates the patient's life.

Back  -    New Search

aorta (ay-or-t) n. (pl. aortae or aortas)

the main artery of the body, from which all others derive. abdominal a. the part of the descending aorta below the diaphragm. arch of the a. the part of the aorta that arches over the heart. ascending a. the part of the aorta that arises from the left ventricle. descending a. the part of the aorta that descends in front of the backbone. thoracic a. the part of the descending aorta from the arch of the aorta to the diaphragm.
—aortic (ay-or-tik) adj.

Back  -    New Search

aortic aneurysm n.

see ANEURYSM.

Back  -    New Search

aortic regurgitation n.

reflux of blood from the aorta into the left ventricle during diastole. Aortic regurgitation most commonly follows scarring of the aortic valve as a result of previous acute rheumatic fever, but it may also result from other conditions, such as syphilis or dissecting aneurysm.

Back  -    New Search

aortic replacement n.

a surgical technique used to replace a diseased length of aorta, most often the abdominal aorta. It usually involves inserting into the aorta a flexible tube of artificial material, which functions as a substitute for the diseased section.

Back  -    New Search

aortic stenosis n.

narrowing of the opening of the aortic valve due to fusion of the cusps that comprise the valve. It may result from previous rheumatic fever, or from calcification and scarring in a valve that has two cusps instead of the normal three, or it may be congenital.

Back  -    New Search

aortic valve n.

see SEMILUNAR VALVE.

Back  -    New Search

aortitis (ay-or-ty-tis) n.

inflammation of the aorta, which most commonly occurs as a late complication of syphilis.

Back  -    New Search

aortography (ay-or-tog-rfi) n.

X-ray examination of the aorta, which involves the injection into it of a radiopaque contrast medium, after which a series of X-rays is taken (see ANGIOCARDIOGRAPHY).

Back  -    New Search

aperient (-peer-int) n.

a mild laxative.

Back  -    New Search

aperistalsis (ay-pe-ri-stal-sis) n.

the absence of peristaltic movement in the intestines.

Back  -    New Search

apex (ay-peks) n.

the tip or summit of an organ; for example the heart or lung. The apex of a tooth is the tip of the root. See also APICAL.

Back  -    New Search

apex beat n.

the impact of the heart against the chest wall during systole. It can be felt or heard to the left of the breastbone, in the space between the fifth and sixth ribs.

Back  -    New Search

Apgar score (ap-gar) n.

a method of rapidly assessing the general state of a baby immediately after birth. A maximum of 2 points is given for each of the following signs, usually measured at one minute and five minutes after delivery: type of breathing, heart rate, colour, muscle tone, and response to stimuli. [V. Apgar (1909–74), US anaesthetist]

Back  -    New Search

aphagia (-fay-ji) n.

loss of the ability to swallow.

Back  -    New Search

aphakia (-fay-ki) n.

absence of the lens of the eye: the state of the eye after a cataract has been removed.

Back  -    New Search

aphasia (dysphasia) (-fay-zi) n.

a disorder of language affecting the generation and content of speech and its understanding. It is caused by disease in the left half of the brain (the dominant hemisphere) in a right-handed person.
—aphasic adj.

Back  -    New Search

aphonia (-foh-ni) n.

absence or loss of the voice caused by disease of the larynx or mouth or disease of the nerves and muscles involved in the generation and articulation of speech.

Back  -    New Search

aphrodisiac (afr-diz-iak) n.

an agent that stimulates sexual excitement.

Back  -    New Search

aphtha (af-th) n. (pl. aphthae)

a small ulcer, occurring singly or in groups in the mouth as white or red spots.
—aphthous adj.

Back  -    New Search

apical (ay-pi-k'l) adj.

of or relating to the apex of an organ or tooth. a. abscess see ABSCESS.

Back  -    New Search

apicectomy (ay-pi-sek-tmi) n.

(in dentistry) surgical removal of the apex of the root of a tooth.

Back  -    New Search

aplasia (-play-zi) n.

total or partial failure of development of an organ or tissue. See also AGENESIS.
—aplastic (ay-plas-tik) adj.

Back  -    New Search

aplastic anaemia n.

a severe form of anaemia, resistant to therapy, in which the bone marrow fails to produce new blood cells. There are several causes, including a reaction to toxic drugs.

Back  -    New Search

apnoea (ap-nee-) n.

temporary cessation of breathing from any cause. a. monitor an electronic alarm, responding to a baby's breathing movements, that can monitor babies at risk from cot death. See also SLEEP APNOEA.
—apnoeic adj.

Back  -    New Search

apocrine (ap--kryn) adj.

1 describing sweat glands that occur only in hairy parts of the body, especially the armpit and groin. These glands develop in the hair follicles and appear after puberty has been reached. Compare ECCRINE.

2 describing a type of gland that loses part of its protoplasm when secreting. see SECRETION.
Top

Back  -    New Search

apocrinitis (ap--krin-I-tis) n.

inflammation of the apocrine glands (found in the armpits, groin, and perineum), characterized by chronicity and subcutaneous septic tracks. See HIDRADENITIS SUPPURATIVA.

Back  -    New Search

apomorphine (ap-mor-feen) n.

an emetic that produces its effect by direct action on the vomiting centre in the brain. It is administered by subcutaneous injection in the treatment of poisoning by noncorrosive substances that have been taken by mouth.

Back  -    New Search

aponeurosis (ap-newr-oh-sis) n.

a thin but strong fibrous sheet of tissue that replaces a tendon in muscles that are flat and sheetlike and have a wide area of attachment (e.g. to bones).
—aponeurotic (ap-newr-ot-ik) adj.

Back  -    New Search

apophysis (-pof-i-sis) n.

a protuberance of bone to which a tendon is attached. a. cerebri the pineal gland.
—apophyseal adj.

Back  -    New Search

apophysitis (-pof-i-sy-tis) n.

inflammation caused by excessive pull of a tendon on the apophysis to which it is attached. See OSGOOD-SCHLATTER DISEASE, SEVER'S DISEASE.

Back  -    New Search

apoplexy (ap--plek-si) n.

see STROKE.

Back  -    New Search

apoptosis (-pop-t-sis) n.

programmed cell death, which results in the ordered removal of cells and occurs naturally as part of the normal development, maintenance, and renewal of cells, tissues, and organs. Failure of apoptosis has been implicated in the uncontrolled cell division that occurs in cancer.

Back  -    New Search

appendectomy (ap-n-dek-tmi) n.

US appendicectomy.

Back  -    New Search

appendicectomy (-pen-di-sek-tmi) n.

surgical removal of the vermiform appendix. See also APPENDICITIS.

Back  -    New Search

appendicitis (-pen-di-sy-tis) n.

inflammation of the vermiform appendix. acute a. the most common form of the condition, usually affecting young people. The chief symptom is abdominal pain, first central and later in the right lower abdomen, over the appendix. If not treated by surgical removal (appendicectomy) the condition usually progresses to cause an abscess or generalized peritonitis. chronic a. a formerly popular diagnosis to explain recurrent pains in the lower abdomen. It is rare, and appendicectomy will not usually cure such pains.

Back  -    New Search

appendicular (ap-n-dik-yoo-ler) adj.

1 relating to or affecting the vermiform appendix.

2 relating to the limbs.
Top

Back  -    New Search

appendix (vermiform appendix) (-pen-diks) n.

the short thin blind-ended tube, 7–10 cm long, that is attached to the end of the caecum. It has no known function in man and is liable to become infected and inflamed (see APPENDICITIS).

Back  -    New Search

apperception (ap-er-sep-shn) n.

(in psychology) the process by which the qualities of an object, situation, etc., perceived by an individual are correlated with his/her preexisting knowledge.

Back  -    New Search

appestat (ap-s-tat) n.

a region in the brain that controls the amount of food in take. Appetite suppressants probably decrease hunger by changing the chemical characteristics of this centre.

Back  -    New Search

applanation (ap-l-nay-shn) n.

flattening of the cornea. It is used to determine intraocular pressure (a. tonometry. ) See OPHTHALMOTONOMETER.

Back  -    New Search

applicator (ap-li-kay-ter) n.

any device used to apply medication or treatment to a particular part of the body.

Back  -    New Search

apposition (ap-zish-n) n.

the state of two structures, such as parts of the body, being in close contact. For example, the fingers are brought into apposition when the fist is clenched.

Back  -    New Search

appraisal (-pray-z'l) n.

the evaluation of an individual's performance, usually by an immediate line manager. Appraisals are performed on a regular basis for National Health Service employees.

Back  -    New Search

apraclonidine (ap-r-kloh-ni-deen) n.

a sympathomimetic drug administered in the form of eye drops to reduce or prevent raised intraocular pressure after laser surgery. Trade name: lopidine .

Back  -    New Search

apraxia (dyspraxia) (-praks-i) n.

an inability to make skilled movements with accuracy. This is a disorder of the cerebral cortex most often caused by disease of the parietal lobes of the brain.

Back  -    New Search

aprotinin (-proh-tin-in) n.

a drug that prevents the breakdown of blood clots (fibrinolysis) by blocking the action of the enzyme plasmin, i.e. it is an antifibrinolytic drug. It is administered by injection to control the severe bleeding that may occur in certain cancers and with fibrinolytic treatments. Trade name: Trasylol .

Back  -    New Search

APT n.

alum precipitated toxoid: a preparation used for immunization against diphtheria.

Back  -    New Search

APUD cells pl. n.

cells that share the metabolic property of amine-precursor uptake and decarboxylation. They are widely distributed, especially in the mucosa of the gastrointestinal tract and pancreas, and are able to form a large variety of peptide substances.

Back  -    New Search

apudoma (apuud-oh-m) n.

a tumour that contains APUD cells and may give rise to symptoms caused by excessive production of the hormones and other peptides that these cells produce. Argentaffinomas, gastrinomas, and vipomas are examples.

Back  -    New Search

apyrexia (ap-l-reks-i) n.

the absence of fever.

Back  -    New Search

aqua (ak-w) n.

water. a. destillata distilled water. a. fortis nitric acid.

Back  -    New Search

aqueduct (ak-wi-dukt) n.

(in anatomy) a canal containing fluid. a. of the midbrain (cerebral a. , a. of Sylvius ) a canal connecting the third and fourth ventricles. [F. Sylvius de la Boe (1614–72), French anatomist]

Back  -    New Search

aqueous humour (ay-kwi-s) n.

the watery fluid that fills the chamber of the eye immediately behind the cornea and in front of the lens.

Back  -    New Search

arachidonic acid (-rak-i-don-ik) n.

see ESSENTIAL FATTY ACID.

Back  -    New Search

arachnodactyly (-rak-noh-dak-tili) n.

see MARFAN'S SYNDROME.

Back  -    New Search

arachnoid (arachnoid mater) (-rak-noid) n.

the middle of the three membranes covering the brain and spinal cord (see MENINGES), which has a fine, almost cobweb-like, texture. a. villi thin-walled projections of the arachnoid into the blood-filled sinuses of the dura, through which cerebrospinal fluid flows from the subarachnoid space into the bloodstream. Large villi (Pacchionian bodies ) are found in the region of the superior sagittal sinus.

Back  -    New Search

arachnoiditis (-rak-noid-l-tis) n.

an inflammatory process causing thickening and scarring (fibrosis) of the membranous linings (meninges) of the spinal canal. The resulting entrapment of nerve roots may result in weakness, pain, and numbness in the affected area. Arachnoiditis may result from infection of the meninges, surgery, or as a response to the oil-based dyes formerly used in myelography.

Back  -    New Search

arbor (ar-ber) n.

(in anatomy) a treelike structure. a. vitae 1 the treelike outline of white matter seen in sections of the cerebellum.

2 the treelike appearance of the inner folds of the cervix (neck) of the uterus.
Top

Back  -    New Search

arborization (ar-ber-l-zay-shn) n.

the branching termination of certain neurone processes.

Back  -    New Search

arbovirus (ar-boh-vy-rs) n.

one of a group of RNA-containing viruses that are transmitted by arthropods (hence arthropod-borne viruses) and cause diseases resulting in encephalitis or serious fever, such as dengue and yellow fever.

Back  -    New Search

ARC n.

AIDS-related complex: see AIDS.

Back  -    New Search

arch- (arche-, archi-, archo-) prefix

denoting first; beginning; primitive; ancestral.

Back  -    New Search

arcus (ar-ks) n.

(in anatomy) an arch. a. senilis a greyish line in the periphery of the cornea, common in the elderly. It begins above and below the cornea but may become a continuous ring.

Back  -    New Search

ARDS n.

see ADULT RESPIRATORY DISTRESS SYNDROME.

Back  -    New Search

areola (-ree-l) n.

1 the brownish or pink ring of tissue surrounding the nipple of the breast.

2 the part of the iris that surrounds the pupil of the eye.
Top

3 a small space in a tissue.
Top

—areolar (-ree-ler) adj.

Back  -    New Search

areolar tissue n.

loose connective tissue consisting of a meshwork of collagen, elastic tissue, and reticular fibres interspersed with numerous connective tissue cells.

Back  -    New Search

argentaffin cells (ar-jen-t-fin) pl. n.

cells that stain readily with silver salts. Such cells occur, for example, in the crypts of Lieberkühn in the intestine.

Back  -    New Search

argentaffinoma (carcinoid) (ar-jen-tafi-noh-m) n.

a tumour of the argentaffin cells in the glands of the intestine (see APUDOMA). Argentaffinomas typically occur in the tip of the appendix and are among the commonest tumours of the small intestine.

Back  -    New Search

arginine (ar-ji-neen) n.

an amino acid that plays an important role in the formation of urea by the liver.

Back  -    New Search

argon laser (ar-gn) n.

see LASER.

Back  -    New Search

Argyll Robertson pupil (ar-gyl rob-ert-sn) n.

a disorder of the eyes, common to several diseases of the central nervous system, in which the pupillary (light) reflex is absent. Although the pupils contract normally for near vision, they fail to contract in bright light. [D. Argyll Robertson (1837–1909), Scottish ophthalmologist]

Back  -    New Search

ariboflavinosis (-ry-boh-flay-vin-oh-sis) n.

the group of symptoms caused by deficiency of riboflavin (vitamin B_2). These symptoms include inflammation of the tongue and lips and sores in the corners of the mouth.

Back  -    New Search

ARM n.

artificial rupture of membranes: see AMNIOTOMY.

Back  -    New Search

ARMD n.

age-related macular degeneration. See MACULAR DEGENERATION.

Back  -    New Search

Arnold-Chiari malformation (ar-n'ld ki-ar-i) n.

a congenital disorder in which there is distortion of the base of the skull with protrusion of the lower brainstem and parts of the cerebellum. [J. Arnold (1835–1915) and H. Chiari (1851–1916), German pathologists]

Back  -    New Search

aromatherapy (-roh-m-th'e-r-pi) n.

the therapeutic use of fragrances derived from essential oils. These can be inhaled through an infusion of the essential oils that produce them, or the oils can be combined with a base oil and massaged into the skin.

Back  -    New Search

arrector pili (-rek-tor py-ly) n. (pl. arrectores pilorum)

a small erector muscle attached to the hair follicle. Contraction of the arrectores pilorum causes goose flesh.

Back  -    New Search

arrhythmia (-rith-mi) n.

any deviation from the normal rhythm (sinus rhythm) of the heart. Arrhythmias include ectopic beats, ectopic tachycardias, fibrillation, and heart block. sinus a. a normal variation in the heart rate, which accelerates slightly on inspiration and slows on expiration.

Back  -    New Search

arsenic (ar-sn-ik) n.

a poisonous greyish metallic element producing the symptoms of nausea, vomiting, diarrhoea, cramps, convulsions, and coma when ingested in large doses. Arsenic was formerly used in medicine, the most important arsenical drugs being arsphenamine (Salvarsan) and neoarsphenamine , used in the treatment of syphilis and dangerous parasitic diseases. Symbol: As.

Back  -    New Search

arter- (arteri-, arterio-) prefix

denoting an artery.

Back  -    New Search

arteriectomy (ar-teer-i-ek-tmi) n.

surgical excision of an artery or part of an artery.

Back  -    New Search

arteriogram (ar-teer-i-oh-gram) n.

1 the final display, on photographic film or a TV monitor, of the images produced during arteriography.

2 a tracing of the wave form of an arterial pulse.
Top

Back  -    New Search

arteriography (ar-teer-i-og-rfi) n.

X-ray examination of an artery that has been outlined by the injection of a radiopaque contrast medium.

Back  -    New Search

arteriole (ar-teer-i-ohl) n.

a small branch of an artery, leading into many smaller vessels — the capillaries. By their constriction and dilation, under the regulation of the sympathetic nervous system, arterioles are the principal controllers of blood flow and pressure.

Back  -    New Search

arteriopathy (ar-teer-i-op-thi) n.

disease of an artery.

Back  -    New Search

arterioplasty (ar-teer-i-oh-plas-ti) n.

surgical reconstruction of an artery; for example, in the treatment of aneurysms.

Back  -    New Search

arteriorrhaphy (ar-teer-i-o-rfi) n.

suture of an artery.

Back  -    New Search

arteriosclerosis (ar-teer-i-oh-skleer-oh-sis) n.

any of several conditions affecting the arteries, such as atherosclerosis;

Back  -    New Search

Mönckeberg's degeneration,

in which calcium is deposited in the arteries as part of the ageing process; and arteriolosclerosis , in which the walls of small arteries become thickened due to ageing or hypertension.

Back  -    New Search

arteriotomy (ar-teer-i-ot-mi) n.

an incision into, or a needle puncture of, the wall of an artery.

Back  -    New Search

arteriovenous (ar-teer-i-oh-vee-ns) adj.

relating to or affecting an artery and a vein. a. malformation see ANGIOMA.

Back  -    New Search

arteritis (ar-ter-l-tis) n.

an inflammatory disease affecting the muscular walls of the arteries. The affected vessels are swollen and tender and may become blocked. temporal (or giant-cell ) a. a condition that occurs in the elderly. It most commonly affects the arteries of the scalp and blindness may result from thrombosis of the arteries to the eyes.

Back  -    New Search

artery (ar-ter-i) n.

a blood vessel carrying blood away from the heart. The walls of arteries contain smooth muscle fibres, which contract or relax under the control of the sympathetic nervous system. See also AORTA, ARTERIOLE. —arterial (ar-teer-il) adj.

Back  -    New Search

arthr- (arthro-) prefix

denoting a joint.

Back  -    New Search

arthralgia (arth-ral-j) n.

pain in a joint, without swelling or other signs of arthritis. Compare ARTHRITIS.

Back  -    New Search

arthrectomy (arth-rek-tmi) n.

surgical excision of a joint.

Back  -    New Search

arthritis (arth-ry-tis) n.

inflammation of one or more joints, characterized by swelling, warmth, redness of the overlying skin, pain, and restriction of motion. Any disease involving the synovial membranes or resulting in the degeneration of cartilage may cause arthritis. Treatment of arthritis depends on the cause, but aspirin and similar analgesics are often used to suppress inflammation, and hence reduce pain and swelling. See also OSTEOARTHRITIS, PSORIASIS, RHEUMATOID ARTHRITIS, SEPTIC (ARTHRITIS), HAEMARTHROSIS, PYARTHROSIS, HYDRARTHROSIS.
—arthritic (arth-rit-ik) adj.

Back  -    New Search

arthroclasia (arth-roh-klay-zi) n.

the surgical breaking down of ankylosis in a joint to permit freer movement.

Back  -    New Search

arthrodesis (arth-roh-dee-sis) n.

fusion of bones across a joint space by surgical means, which eliminates movement.

Back  -    New Search

arthrodynia (arth-roh-din-i) n.

pain in a joint.

Back  -    New Search

arthrography (arth-rog-rfi) n.

an X-ray technique for examining joints. A contrast medium (either air or a liquid opaque to X-rays) is injected into the joint space, allowing its outline and contents to be traced accurately.

Back  -    New Search

arthrogryposis (arth-roh-gri-poh-sis) n.

contracture of soft tissues that causes fixed deformities of the joints if untreated. a. multiplex congenita a congenital disease with multiple causes in which there are contractures, stiff joints, and absent skin creases, as a result of the muscles being replaced by fibrous tissue.

Back  -    New Search

arthropathy (arth-rop-thi) n.

any disease or disorder involving a joint.

Back  -    New Search

arthroplasty (arth-roh-plasti) n.

surgical remodelling of a diseased joint. To prevent the ends of the bones fusing after the operation, a large gap may be created between them (gap or excision a. ), a barrier of artificial material may be inserted (interposition a. ), or one or both bone ends may be replaced by a prosthesis of metal or plastic (replacement a. ). McKee-Farrar a. replacement arthroplasty of the hip joint. Both the head of the femur and the acetabulum are replaced by metal prostheses; the replacement acetabulum is cemented into the bone. total a. replacement arthroplasty in which both joint surfaces are replaced. See also HEMIARTHROPLASTY.

Back  -    New Search

arthroscope (arth-roh-skohp) n.

a telescope that is inserted into a joint through a small incision in order to inspect its contents (see ARTHROSCOPY).

Back  -    New Search

arthroscopy (ar-thros-kpi) n.

inspection of a joint cavity with an arthroscope, enabling percutaneous surgery (such as meniscectomy) and biopsy to be performed.

Back  -    New Search

arthrotomy (arth-rot-mi) n.

a surgical incision to open a joint in order to inspect the contents or to drain pus (in septic arthritis).

Back  -    New Search

articulation (ar-tik-yoo-lay-shn) n.

(in anatomy) the point or type of contact between two bones. See JOINT.

Back  -    New Search

artificial heart (ar-ti-fish-l) n.

a titanium pump that is implanted into the body to take over the function of a failing left ventricle in patients with heart disease. This allows the diseased ventricle time to recover its function. The pump is powered by an external battery, strapped to the patient's body, to which it is connected by wires passed through the patient's skin. The most recent devices are small enough to fit into the heart itself.

Back  -    New Search

artificial insemination n.

instrumental introduction of semen into the vagina in order that a woman may conceive. The semen specimen may be provided by the husband (AIH — artificial insemination husband ) in cases of impotence or by an anonymous donor (DI — donor insemination ), usually in cases where the husband is sterile.

Back  -    New Search

artificial kidney (dialyser) n.

see HAEMODIALYSIS.

Back  -    New Search

artificial lung n.

see RESPIRATOR.

Back  -    New Search

artificial respiration n.

an emergency procedure for maintaining a flow of air into and out of a patient's lungs when the natural breathing reflexes are absent or insufficient. The simplest and most efficient method is mouth-to-mouth respiration.

Back  -    New Search

artificial rupture of membranes (ARM) n.

see AMNIOTOMY.

Back  -    New Search

artificial sphincter n.

an apparatus designed to replace or support a sphincter that is either absent or ineffective. See also NEOSPHINCTER.

Back  -    New Search

arytenoid cartilage (a-ri-tee-noid) n.

either of the two pyramid-shaped cartilages that lie at the back of the larynx next to the upper edges of the cricoid cartilage.

Back  -    New Search

arytenoidectomy (a-ri-tee-noid-ek-tmi) n.

surgical excision of the arytenoid cartilage of the larynx in the treatment of paralysis of the vocal folds.

Back  -    New Search

asbestos (ass-best-os) n.

a fibrous mineral that is incombustible and does not conduct heat. It is used in the form of fabric or boards for its heat-resistant properties.

Back  -    New Search

asbestosis (ass-best-oh-sis) n.

a lung disease — a form of pneumoconiosis — caused by fibres of asbestos inhaled by those who are exposed to the mineral. See also MESOTHELIOMA.

Back  -    New Search

ascariasis (ask-ry-sis) n.

a disease caused by an infestation with the parasitic worm Ascaris lumbricoides. Adult worms in the intestine can cause abdominal pain, vomiting, constipation, diarrhoea, appendicitis, and peritonitis; migrating larvae in the lungs can provoke pneumonia.

Back  -    New Search

Ascaris (ass-k-ris) n.

a genus of parasitic nematode worms. A. lumbricoides the largest of the human intestinal nematodes. Larvae hatch out in the intestine and then migrate via the hepatic portal vein, liver, heart, lungs, windpipe, and pharynx, before returning to the intestine where they later develop into adult worms (see also ASCARIASIS).

Back  -    New Search

Aschoff nodules (ash-off) pl. n.

nodules that occur in the muscular and connective tissue of the heart in rheumatic myocarditis. [K. A. L. Aschoff (1866–1942), German pathologist]

Back  -    New Search

ascites (hydroperitoneum) (-sy-teez) n.

the accumulation of fluid in the peritoneal cavity, causing abdominal swelling. chylous a. ascites that occurs when the drainage of lymph from the abdomen is obstructed. See also OEDEMA.

Back  -    New Search

ascorbic acid (-skor-bik) n.

see VITAMIN C.

Back  -    New Search

ASD n.

see (ATRIAL) SEPTAL DEFECT.

Back  -    New Search

-ase suffix

denoting an enzyme.

Back  -    New Search

asepsis (ay-sep-sis) n.

the complete absence of bacteria, fungi, viruses, or other microorganisms that could cause disease. Asepsis is the ideal state for the performance of surgical operations and is achieved by using sterilization techniques.
—aseptic adj.

Back  -    New Search

Asherman syndrome (ash-er-mn) n.

a condition in which amenorrhoea and infertility follow a major haemorrhage in pregnancy. It may result from overvigorous curettage of the uterus in an attempt to control the bleeding. This removes the lining, the walls adhere, and the cavity is obliterated to a greater or lesser degree. Compare SHEEHAN'S SYNDROME. [J. G. Asherman (20th century), Czechoslovakian gynaecologist]

Back  -    New Search

asparaginase (-spa-r-jin-ayz) n.

an enzyme that inhibits the growth of certain tumours and is used almost exclusively in the treatment of acute lymphoblastic leukaemia. Trade name: Erwinase .

Back  -    New Search

asparagine (-spa-r-jeen) n.

see AMINO ACID.

Back  -    New Search

aspartate aminotransferase (AST) (ass-par-tayt) n.

an enzyme involved in the transamination of amino acids. Measurement of AST in the serum may be used in the diagnosis of acute myocardial infarction and acute liver disease. The former name, serum glutamic oxalo-acetic transaminase (SGOT), is still widely used.

Back  -    New Search

aspartic acid (aspartate) (-spar-tik) n.

see AMINO ACID.

Back  -    New Search

Asperger's syndrome (ass-per-gerz) n.

a mild form of autism characterized by aloofness, lack of interest in other people, stilted and pedantic styles of speech, and an excessive preoccupation with a very specialized interest (such as timetables). [H. Asperger (20th century)]

Back  -    New Search

aspergillosis (ass-per-jil-oh-sis) n.

a group of conditions caused by fungi of the genus Aspergillus, usually Aspergillus fumigatus. These conditions nearly always arise in patients with pre-existing lung disease and fall into three categories. The allergic form most commonly affects asthmatic patients and may cause collapse of segments or lobes of a lung. The colonizing form leads to formation of a fungus ball (aspergilloma ), usually within a pre-existing cavity in the lung. In the third form the fungus spreads throughout the lungs and may even disseminate throughout the body; this form is rare but potentially fatal.

Back  -    New Search

Aspergillus (ass-per-jil-s) n.

a genus of fungi, including many common moulds, some of which cause infections of the respiratory system in man. A. fumigatus the cause of aspergillosis.

Back  -    New Search

aspermia (-sperm-i) n.

strictly, a lack or failure of formation of semen. More usually, however, the term is used to mean the total absence of sperm from the semen (see AZOOSPERMIA).

Back  -    New Search

asphyxia (-sfiks-i) n.

suffocation: a life-threatening condition in which oxygen is prevented from reaching the tissues by obstruction of or damage to any part of the respiratory system.

Back  -    New Search

aspiration (ass-per-ay-shn) n.

the withdrawal of fluid from the body by means of suction. vacuum a. a method of terminating pregnancy by suction of the products of conception through an intrauterine cannula. See also (ASPIRATION) CYTOLOGY, ENDOMETRIAL (ASPIRATION).

Back  -    New Search

aspirator (ass-per-ay-ter) n.

any of various instruments used for aspiration. Some employ hollow needles for removing fluid from cysts, inflamed joint cavities, etc., another kind is used to suck debris and water from the patient's mouth during dental treatment.

Back  -    New Search

aspirin (acetylsalicylic acid) (ass-prin) n.

a widely used drug that relieves pain and also reduces inflammation and fever. It is taken by mouth for the relief of headache, toothache, neuralgias, etc. It is also taken to reduce fever in influenza and the common cold, and daily doses are used in the prevention of coronary thrombosis and strokes in those at risk. Aspirin works by inhibiting the production of prostaglandins; it may irritate the lining of the stomach, causing nausea, vomiting, pain, and bleeding. It has been implicated as a cause of Reye's syndrome and should therefore not be given to children below the age of 12 unless specifically indicated.

Back  -    New Search

assertion (-ser-shn) n.

the skill to communicate positively in order to press one's own claims, rights, or opinions.

Back  -    New Search

assessment (-ses-mnt) n.

1 the first stage of the nursing process, in which data about the patient's health status is collected and from which a nursing care plan may be devised.

2 an examination set by an examining body to test a candidate's theoretical and practical nursing skills.
Top

Back  -    New Search

assimilation (-simi-lay-shn) n.

the process by which food substances are taken into the cells of the body after they have been digested and absorbed.

Back  -    New Search

associate nurse (-soh-si-t) n.

a nurse who provides care for a patient on the instructions of the patient's primary nurse or in her absence. See PRIMARY NURSING.

Back  -    New Search

association area (-soh-si-ay-shn) n.

an area of cerebral cortex that lies away from the main areas that are concerned with the reception of sensory impulses and the start of motor impulses but is linked to them by many neurones (association fibres ).

Back  -    New Search

association of ideas n.

(in psychology) linkage of one idea to another in a regular way according to their meaning. See also FREE ASSOCIATION.

Back  -    New Search

AST n.

see ASPARTATE AMINOTRANSFERASE.

Back  -    New Search

astemizole (ass-tem-i-zohl) n.

an antihistamine drug used to treat hay fever and allergic skin conditions. It is administered by mouth. Trade name: Hismanal .

Back  -    New Search

astereognosis (-ste-ri-g-noh-sis) n.

see AGNOSIA.

Back  -    New Search

asteroid hyalosis (ass-t-roid hy--loh-sis) n.

a degenerative condition, formerly known as asteroid hyalitis , in which tiny deposits of calcium are suspended in the vitreous humour. Vision is not affected.

Back  -    New Search

asthenia (ass-theen-i) n.

weakness or loss of strength.

Back  -    New Search

asthenic (ass-th'en-ik) adj.

describing a personality disorder characterized by low energy, susceptibility to physical and emotional stress, and a diminished capacity for pleasure.

Back  -    New Search

asthenopia (ass-thi-noh-pi) n.

see EYE-STRAIN.

Back  -    New Search

asthenospermia (ass-thi-noh-sper-mi) n.

the presence in the semen of spermatozoa with poor motility, revealed by seminal analysis.

Back  -    New Search

asthma (ass-m) n.

the condition of subjects with widespread narrowing of the bronchial airways, which changes in severity over short periods of time and leads to coughing, wheezing, and difficulty in breathing. bronchial a. asthma that may be precipitated by exposure to one or more of a wide range of stimuli, including allergens, drugs (such as aspirin), exertion, emotion, infections, and air pollution. Treatment is with bronchodilators, with or without corticosteroids, usually administered via aerosol or dry-powder inhalers, or — if the condition is more severe — via a nebulizer. Severe asthmatic attacks may need large doses or oral corticosteroids (see STATUS ASTHMATICUS). cardiac a. asthma that occurs in left ventricular heart failure and must be distinguished from bronchial asthma, as the treatment is quite different.
—asthmatic (ass-mat-ik) adj.

Back  -    New Search

astigmatism (-stig-m-tizm) n.

a defect of vision in which the image of an object is distorted because not all the light rays come to a focus on the retina. This is usually due to abnormal curvature of the cornea and/or lens, whose surface resembles part of the surface of an egg (rather than a sphere).
—astigmatic (ass-tig-mat-ik) adj.

Back  -    New Search

astragalus (ass-trag-ls) n.

see TALUS.

Back  -    New Search

astringent (-strin-jnt) n.

a drug that causes cells to shrink by precipitating proteins from their surfaces. Astringents are used in lotions to harden and protect the skin and to reduce bleeding from minor abrasions.

Back  -    New Search

astrocytoma (ass-troh-sy-toh-m) n.

any brain tumour derived from non-nervous supporting cells (glia), which may be benign or malignant. In adults astrocytomas are usually found in the cerebral hemispheres but in children they also occur in the cerebellum.

Back  -    New Search

asymmetry (ay-sim-it-ri) n.

(in anatomy) the state in which opposite parts of an organ or parts at opposite sides of the body do not correspond with each other.
—asymmetric (ay-si-met-rik) adj.

Back  -    New Search

asymptomatic (ay-simp-tm-at-ik) adj.

not showing any symptoms of disease, whether disease is present or not.

Back  -    New Search

asynclitism (-sin-klit-izm) n.

tilting of the fetal skull towards one or other shoulder causing the top of the skull to be either nearer to the sacrum (anterior a. or Naegele's obliquity ) or nearer to the pubis (posterior a. or Litzmann's obliquity ). These mechanisms enable the fetal head to pass more easily through the maternal pelvis.

Back  -    New Search

asynergia (a-sin-er-ji) n.

see DYSSYNERGIA.

Back  -    New Search

asystole (-sis-t-li) n.

a condition in which the heart no longer beats, accompanied by the absence of complexes in the electrocardiogram.

Back  -    New Search

atacurium besylate (at--kewr-im bes-il-ayt) n.

a muscle relaxant administered by injection during anaesthesia. Trade name: Tracrium .

Back  -    New Search

ataraxia (at--raks-i) n.

a state of calmness and freedom from anxiety, especially the state produced by tranquillizing drugs.

Back  -    New Search

atavism (at--vizm) n.

the phenomenon in which an individual has a character or disease known to have occurred in a remote ancestor but not in his parents.

Back  -    New Search

ataxia (-taks-i) n.

the shaky movements and unsteady gait that result from the brain's failure to regulate the body's posture and the strength and direction of limb movements. cerebellar a. a condition in which the patient staggers when walking, cannot pronounce words properly, and may have nystagmus. Friedreich's a. an inherited disorder appearing first in adolescence. It has the features of cerebellar ataxia, together with spasticity of the limbs. sensory a. ataxia that is exaggerated when the patient closes his eyes (see ROMBERG'S SIGN). See also ATAXIA TELANGIECTASIA, TABES DORSALIS (LOCOMOTOR ATAXIA).
—ataxic adj.

Back  -    New Search

ataxia telangiectasia (til-an-ji-ek-tay-zi) n.

an inherited (autosomal recessive) neurological disorder. Ataxia is usually noted early in life. Mental retardation, growth retardation, abnormal eye movements, skin lesions, and immune deficiency may be found. Affected individuals may develop malignant disease.

Back  -    New Search

atel- (atelo-) prefix

denoting imperfect or incomplete development.

Back  -    New Search

atelectasis (at--lek-t-sis) n.

failure of part of the lung to expand. This occurs when the cells lining the alveoli are immature, as in premature babies; it also occurs when the larger bronchial tubes are blocked by retained secretions, inhaled foreign bodies, bronchial cancers, or enlarged lymph nodes.

Back  -    New Search

atenolol n.

a drug (see BETA BLOCKER) used to treat angina and high blood pressure. It is taken by mouth and the commonest side-effects are fatigue, depression, and digestive upsets. Trade name: Tenormin .

Back  -    New Search

atherogenic (ath-er-oh-jen-ik) adj.

denoting a factor that may cause atheroma. Such factors include cigarette smoking, excessive consumption of animal fats and refined sugar, obesity, and inactivity.

Back  -    New Search

atheroma (ath-er-oh-ma) n.

degeneration of the walls of the arteries due to the formation in them of fatty plaques and scar tissue. This limits blood circulation and predisposes to thrombosis.
—atheromatous adj.

Back  -    New Search

atherosclerosis (ath-er-oh-skleer-oh-sis) n.

a disease of the arteries in which fatty plaques develop on their inner walls, with eventual obstruction of blood flow. See ATHEROMA.

Back  -    New Search

athetosis (ath--toh-sis) n.

a writhing involuntary movement especially affecting the hands, face, and tongue. It is usually a form of cerebral palsy but can be caused by drugs used to treat parkinsonism or by the withdrawal of phenothiazines.
—athetotic adj.

Back  -    New Search

athlete's foot (ath-leets) n.

a fungus infection of the skin between the toes: a type of ringworm. Medical name: tinea pedis .

Back  -    New Search

atlas (at-ls) n.

the first cervical vertebra, by means of which the skull is articulated to the backbone.

Back  -    New Search

ATLS n.

advanced trauma life support, which comprises the treatment programmes for patients who have been subjected to major trauma (e.g. serious road traffic accidents, missile injuries). Doctors, nurses, and paramedical personnel involved in ATLS receive special training for dealing with such emergencies.

Back  -    New Search

atom (at-m) n.

the smallest constituent of an element that can take part in a chemical reaction. An atom consists of a positively charged nucleus with negatively charged electrons orbiting around it.

Back  -    New Search

atomizer (at--my-zer) n.

an instrument that reduces liquids to a fine spray of minute droplets.

Back  -    New Search

atony (at-ni) n.

a state in which muscles are floppy, lacking their normal elasticity.
—atonic (-ton-ik) adj.

Back  -    New Search

atopen (at-oh-pn) n.

see ATOPY.

Back  -    New Search

atopy (at-oh-pi) n.

a form of allergy in which there is a hereditary or constitutional tendency to develop hypersensitivity reactions (e.g. hay fever, allergic asthma, atopic eczema) in response to allergens (atopens ). Individuals with this predisposition — and the conditions provoked in them by contact with allergens — are described as atopic .

Back  -    New Search

ATP (adenosine triphosphate) n.

a compound that contains adenine, ribose, and three phosphate groups and occurs in cells. The chemical bonds of the phosphate groups store energy needed by the cell, for muscle contraction; this energy is released when ATP is split into ADP or AMP. ATP is formed from ADP or AMP using energy produced by the breakdown of carbohydrates or other food substances. See also MITOCHONDRION.

Back  -    New Search

atresia (-tree-zi) n.

1 congenital absence or abnormal narrowing of a body opening. biliary a. narrowing of the bile ducts, which fail to drain, causing jaundice in affected babies. duodenal a. narrowing of the duodenum, causing complete obstruction of its lumen. tricuspid a. absence of the tricuspid valve, with resultant lack of communication between the right atrium and right ventricle of the heart.

2 the degenerative process that affects the majority of ovarian follicles. Usually only one Graafian follicle will ovulate in each menstrual cycle.
Top

—atretic (-tret-ik) adj.

Back  -    New Search

atri- (atrio-) prefix

denoting an atrium, especially the atrium of the heart.

Back  -    New Search

atrial (ay-tri-l) adj.

of or relating to the atrium or atria. a. fibrillation see FIBRILLATION. a. septal defect see SEPTAL DEFECT.

Back  -    New Search

atrioventricular (ay-tri-oh-ven-trik-yoo-ler) adj.

relating to the atria and ventricles of the heart.

Back  -    New Search

atrioventricular bundle (AV bundle, bundle of His) n.

a bundle of modified heart muscle fibres (Purkinje fibres ) passing from the atrioventricular (AV) node forward to the septum between the ventricles, where it divides into right and left bundles, one for each ventricle. The fibres transmit contraction waves from the atria, via the AV node, to the ventricles.

Back  -    New Search

atrioventricular node (AV node) n.

a mass of modified heart muscle situated in the lower middle part of the right atrium. It receives the impulse to contract from the sinoatrial node, via the atria, and transmits it through the atrioventricular bundle to the ventricles.

Back  -    New Search

atrium (ay-tri-m) n. (pl. atria)

1 either of the two upper chambers of the heart. The left atrium receives arterial blood from the lungs via the pulmonary artery; the right atrium receives venous blood from the venae cavae. See also AURICLE.

2 any of various anatomical chambers into which one or more cavities open.
Top

—atrial adj.

Back  -    New Search

Atromid-S (at-roh-mid-ess) n.

see CLOFIBRATE.

Back  -    New Search

atrophy (at-r-fi) n.

the wasting away of a normally developed organ or tissue due to degeneration of cells. This may occur through undernourishment, disuse, or ageing. muscular a. atrophy of muscular tissue associated with various diseases, such as poliomyelitis. See also SPINAL MUSCULAR ATROPHY.

Back  -    New Search

atropine (at-r-peen) n.

a drug extracted from belladonna that inhibits the action of certain nerves of the autonomic nervous system (see PARASYMPATHOLYTIC). Atropine relaxes smooth muscle and is used to treat biliary colic and renal colic. It also reduces secretions of the bronchial tubes, salivary glands, stomach, and intestines and is used before general anaesthesia and to relieve peptic ulcers. It is also used to dilate the pupil of the eye. Trade name: Minims atropine .

Back  -    New Search

attachment (-tach-mnt) n.

1 (in psychology) the process of developing the first close selective relationship of a child's life, most commonly with the mother. a. disorder a psychiatric disorder in infants and young children resulting from institutionalization, emotional neglect, or child abuse. Affected children are either withdrawn, aggressive, and fearful or attention-seeking and indiscriminately friendly.

2 (in Britain) working arrangements in the National Health Service by which district nurses, social workers, etc., are engaged in association with specific general practitioners, caring for their registered patients rather than working solely on a geographical or district basis.
Top

Back  -    New Search

attention deficit disorder (ADD, hyperkinetic disorder or hyperactivity disorder) (-ten-shn def-i-sit dis-or-der) n.

a mental disorder, usually of children, characterized by a grossly excessive level of activity and a marked impairment of the ability to attend, resulting in aggressive disruptive behaviour. Treatment usually involves drugs (such as methylphenidate) and behaviour therapy.

Back  -    New Search

attenuation (-ten-yoo-ay-shn) n.

reduction of the disease-producing ability (virulence) of a bacterium or virus so that it may be used for immunization.

Back  -    New Search

atticotomy (at-i-kot-mi) n.

a surgical operation to remove cholesteatoma from the ear. It is a form of limited mastoidectomy.

Back  -    New Search

atypical (ay-tip-ik-l) adj.

not conforming to type. a. antipsychotic see ANTIPSYCHOTICa. facial pain neuralgia typified by pain in the face that does not fit the distribution of nerves. a. pneumonia pneumonia, caused by such organisms as Mycoplasma pneumoniae, that does not respond to penicillin but does respond to such antibiotics as tetracycline and erythromycin.

Back  -    New Search

audi- (audio-) prefix

denoting hearing or sound.

Back  -    New Search

audiogram (aw-di-oh-gram) n.

the graphic record of a test of hearing carried out on an audiometer.

Back  -    New Search

audiology (awdi-ol-ji) n.

the study of disorders of hearing.

Back  -    New Search

audiometer (awdi-om-it-er) n.

an apparatus for measuring hearing at different sound frequencies, so helping in the diagnosis of deafness.
—audiometry n.

Back  -    New Search

audit (aw-dit) n.

see CLINICAL AUDIT, NURSING AUDIT.

Back  -    New Search

auditory (aw-dit-er-i) adj.

relating to the ear or to the sense of hearing. a. canal the canal leading from the pinna to the eardrum. a. nerve see VESTIBULOCOCHLEAR NERVE.

Back  -    New Search

Auerbach's plexus (myenteric plexus) (ow-er-banks) n.

a collection of nerve fibres — fine branches of the vagus nerve — within the walls of the intestine. It supplies the muscle layers and controls the movements of peristalsis. [L. Auerbach (1828–97), German anatomist]

Back  -    New Search

aura (or-) n.

the forewarning of an attack, as occurs in epilepsy and migraine.

Back  -    New Search

aural (or-l) adj.

relating to the ear.

Back  -    New Search

auranofin (or-an-oh-fin) n.

a gold preparation administered by mouth to treat rheumatoid arthritis. Side-effects include nausea, abdominal pain, diarrhoea, and mouth ulcers. Trade name: Ridaura .

Back  -    New Search

Aureomycin (or-i-oh-my-sin) n.

see CHLORTETRACYCLINE.

Back  -    New Search

auricle (or-i-k'l) n.

1 a small pouch in the wall of each atrium of the heart: the term is also used incorrectly as a synonym for atrium.

2 see PINNA.
Top

Back  -    New Search

auriscope (otoscope) (or-i-skohp) n.

an apparatus for examining the eardrum and the external meatus.

Back  -    New Search

auscultation (aw-skl-tay-shn) n.

the process of listening, usually with a stethoscope, to sounds produced by movement of gas or liquid within the body, as an aid to diagnosis.
—auscultatory adj.

Back  -    New Search

Australia antigen (oss-tray-li) n.

another name for the hepatitis B antigen, which was first found in the blood of an Australian aborigine.

Back  -    New Search

aut- (auto-) prefix

denoting self.

Back  -    New Search

autism (aw-tizm) n.

1 (Kanner's syndrome , infantile autism ) a rare psychiatric disorder of childhood marked by severe difficulties in communicating and forming relationships with other people, in developing language, and in using abstract concepts; repetitive and limited patterns of behaviour; and obsessive resistance to tiny changes in familiar surroundings. About 50% of autistic children have learning disabilities, but some are very intelligent and may even be gifted in specific areas.

2 the condition of retreating from realistic thinking to self-centred fantasy thinking: a symptom of personality disorder and schizophrenia.
Top

—autistic adj.

Back  -    New Search

autoantibody (aw-toh-an-ti-bodi) n.

an antibody formed against one of the body's own components in an autoimmune disease.

Back  -    New Search

autoclave (aw-t-klayv)

1 n. a piece of sterilizing equipment in which surgical instruments, dressings, etc., are treated with steam at high pressure.

2 vb. to sterilize in an autoclave.
Top

Back  -    New Search

autograft (aw-t-grahft) n.

a tissue graft taken from one part of the body and transferred to another part of the same individual. Unlike homografts, autografts are not rejected by the body's immunity defences. See also SKIN (GRAFT).

Back  -    New Search

autoimmune disease (aw-toh-i-mewn) n.

one of a group of otherwise unrelated disorders caused by inflammation and destruction of tissues by autoantibodies. These disorders include pernicious anaemia, rheumatic fever, rheumatoid arthritis, glomerulonephritis, myasthenia gravis, and Hashimoto's disease.

Back  -    New Search

autoimmunity (aw-toh-i-mewn-iti) n.

a disorder of the body's defence mechanisms in which antibodies are produced against certain components or products of its own tissues, treating them as foreign material and attacking them. See AUTOIMMUNE DISEASE, IMMUNITY.

Back  -    New Search

autoinfection (aw-toh-in-fek-shn) n.

1 infection by an organism that is already present in the body.

2 infection transferred from one part of the body to another via the fingers, towels, etc.
Top

Back  -    New Search

autointoxication (aw-toh-in-toks-i-kay-shn) n.

poisoning by a toxin formed within the body.

Back  -    New Search

autologous (aw-tol--gs) adj.

denoting a graft that is derived from the recipient of the graft.

Back  -    New Search

autolysis (aw-tol-i-sis) n.

the destruction of tissues or cells brought about by the actions of their own enzymes. See LYSOSOME.

Back  -    New Search

automatism (aw-tom--tizm) n.

behaviour that may be associated with epilepsy, in which the patient performs well-organized movements or tasks while unaware of doing so.

Back  -    New Search

autonomic nervous system (aw-t-nom-ik) n.

the part of the nervous system responsible for the control of bodily functions that are not consciously directed, including regular beating of the heart, intestinal movements, sweating, salivation, etc. See PARASYMPATHETIC NERVOUS SYSTEM, SYMPATHETIC NERVOUS SYSTEM.

Back  -    New Search

autonomy (aw-tonn-mi) n.

the right of personal freedom of action, said to be one of the characteristics of a profession.

Back  -    New Search

autopsy (necropsy, post mortem) (aw-top-si) n.

dissection and examination of a body after death in order to determine the cause of death or the presence of disease processes.

Back  -    New Search

autoradiography (radioautography) (aw-toh-ray-di-og-rfi) n.

a technique for examining the distribution of a radioactive tracer in the tissues of an experimental animal.

Back  -    New Search

autoscopy (aw-tos-kpi) n.

the experience of seeing one's whole body as though from a vantage point some distance away. It can be a symptom in epilepsy. See also OUT-OF-THE-BODY EXPERIENCE.

Back  -    New Search

autosomal (aw-t-soh-ml) adj.

denoting an autosome. a. dominant denoting hereditary diseases in which the defective gene is dominant and will therefore tend to be inherited by (and be expressed in) 50% of the offspring (of either sex) of the person with the disease. a. recessive denoting inherited diseases in which the defective gene is recessive but not sex-linked. See also RECESSIVE.

Back  -    New Search

autosome (aw-t-sohm) n.

any chromosome that is not a sex chromosome and that occurs in pairs in diploid cells.

Back  -    New Search

autosuggestion (aw-toh-s-jes-chn) n.

self-suggestion or self-conditioning that involves repeating ideas to oneself in order to change psychological or physiological states. See SUGGESTION.

Back  -    New Search

autotransfusion (aw-toh-trans-few-zhn) n.

reintroduction into a patient of blood that has been lost from the patient's circulation during surgical operation.

Back  -    New Search

aux- (auxo-) prefix

denoting increase; growth.

Back  -    New Search

avascular (-vas-kew-ler) adj.

lacking blood vessels or having a poor blood supply.

Back  -    New Search

aversion therapy (-ver-shn) n.

a form of behaviour therapy that is used (now rarely) to reduce the occurrence of undesirable behaviour. The patient is conditioned by repeated pairing of some unpleasant stimulus with a stimulus related to the undesirable behaviour. See also SENSITIZATION.

Back  -    New Search

avitaminosis (avi-tami-noh-sis) n.

the condition caused by lack of a vitamin. See also DEFICIENCY DISEASE.

Back  -    New Search

AVM n.

arteriovenous malformation (see ANGIOMA).

Back  -    New Search

avoidant (-void-nt) adj.

describing a personality type characterized by self-consciousness, hypersensitivity to rejection and criticism from others, avoidance of normal situations because of their potential risk, high levels of tension and anxiety, and consequently a restricted life.

Back  -    New Search

AVPU n.

a system for assessing the depth of unconsciousness: A = alert; V = voice responses present; P = pain responses present; U = unresponsive. It is useful for judging the severity of head injury and the need for specialized neurosurgical assistance.

Back  -    New Search

avulsion (-vul-shn) n.

the tearing or forcible separation of part of a structure.

Back  -    New Search

axilla (ak-sil-) n. (pl. axillae).

the armpit.
—axillary adj.

Back  -    New Search

axis (aks-is) n.

1 a real or imaginary line through the centre of the body or one of its parts or a line about which the body or a part rotates.

2 the second cervical vertebra, which articulates with the atlas vertebra above and allows rotational movement of the head.
Top

Back  -    New Search

axon (aks-on) n.

a nerve fibre: a single process extending from the cell body of a neurone and carrying nerve impulses away from it.

Back  -    New Search

axonotmesis (aks-on-t-mee-sis) n.

rupture of nerve fibres (axons) within an intact nerve sheath. This may result from prolonged pressure or crushing and it is followed by peripheral degeneration of the nerve beyond the point of rupture. The prognosis for nerve regeneration is good.

Back  -    New Search

azapropazone (az-proh-p-zohn) n.

an anti-inflammatory drug (see NSAID) used to treat rheumatoid arthritis, osteoarthritis, ankylosing spondylitis, and gout. It is administered by mouth. Trade name: Rheumox .

Back  -    New Search

azatadine (ay-zat--deen) n.

an antihistamine drug used to treat hay fever, urticaria, itching, and stings. It is administered by mouth. Trade name: Optimine .

Back  -    New Search

azathioprine (az-th'y--preen) n.

an immunosuppressive drug, used mainly to aid the survival of organ or tissue transplants. Trade name: Imuran .

Back  -    New Search

azelaic acid (az--lay-ik) n.

an antibacterial drug applied externally as a cream in the treatment of acne. Trade name: Skinoren .

Back  -    New Search

azelastine (ay-zel--steen) n.

an antihistamine drug that is administered in a metered-dose nasal spray for the treatment of hay fever. Trade name: Rhinolast .

Back  -    New Search

azithromycin (-zith-roh-my-sin) n.

an antibiotic used to treat respiratory, skin, soft-tissue, and other infections, especially those caused by the organism Chlamydia trachomatis. It is administered by mouth. Trade name: Zithromax .

Back  -    New Search

azlocillin (az-loh-sil-in) n.

a penicillin-type antibiotic used especially to treat infections caused by Pseudomonas aeruginosa. It is administered by intravenous infusion. Trade name: Securopen .

Back  -    New Search

azo- (azoto-) prefix

denoting a nitrogenous compound, such as urea.

Back  -    New Search

azoospermia (aspermia) (ay-zoh--sperm-i) n.

the complete absence of sperm from the seminal fluid.

Back  -    New Search

azotaemia (az-tee-mi) n.

a former name for uraemia.

Back  -    New Search

azoturia (az-tewr-i) n.

the presence in the urine of an abnormally high concentration of nitrogen-containing compounds, especially urea.

Back  -    New Search

aztreonam (az-tree--nam) n.

an antibiotic administered by injection that is used to treat infections caused by Gram-negative organisms (see GRAM'S STAIN). It is especially useful for treating lung infections in children with cystic fibrosis. Trade name: Azactam .

Back  -    New Search

azygos vein (az-i-gos) n.

an unpaired vein that arises from the inferior vena cava and drains into the superior vena cava, returning blood from the thorax and abdominal cavities.

Back  -    New Search

B

Babinski reflex (ba-bin-ski) n.

an upward movement of the great toe that is an abnormal plantar reflex indicating disease in the brain or spinal cord. [J. F. F. Babinski (1857–1932), French neurologist]

Back  -    New Search

baby blues (bay-bi) n.

see POSTNATAL (DEPRESSION).

Back  -    New Search

bacillaemia (ba-si-lee-mi) n.

the presence of bacilli in the blood, resulting from infection.

Back  -    New Search

bacille Calmette-Guérin (ba-seel kal-met gay-ran) n.

see BCG. [A. L. C. Calmette (1863–1933) and C. Guérin (1872–1961), French bacteriologists]

Back  -    New Search

bacilluria (ba-sil-yoor-i) n.

the presence of bacilli in the urine, resulting from a bladder or kidney infection. See CYSTITIS.

Back  -    New Search

bacillus (b-sil-s) n. (pl. bacilli)

any rod-shaped bacterium. See also BACILLUS, LACTOBACILLUS, STREPTOBACILLUS.

Back  -    New Search

Bacillus n.

a large genus of Gram-positive spore-bearing rodlike bacteria. They are widely distributed in soil and air (usually as spores). B. anthracis a nonmotile species that causes anthrax. B. polymyxa the source of the polymyxin group of antibiotics. B. subtilis a species that may cause conjunctivitis in man; it also produces the antibiotic bacitracin.

Back  -    New Search

bacitracin (ba-si-tray-sin) n.

an antibiotic produced by certain strains of bacteria and effective against a number of microorganisms. It is usually applied externally, to treat infections of the skin, eyes, or nose. Trade names: Cicatrin , Polybactrin .

Back  -    New Search

backbone (spinal column, spine, vertebral column) (bak-bohn) n.

the flexible bony column, extending from the base of the skull to the small of the back, that encloses and protects the spinal cord. It is made up of individual bones (see VERTEBRA) connected by discs of fibrocartilage (see INTERVERTEBRAL DISC). The backbone of a newborn baby contains 33 vertebrae: seven cervical, 12 thoracic, five lumbar, five sacral, and four coccygeal. In the adult the sacral and coccygeal vertebrae become fused into two single bones (sacrum and coccyx, respectively). See illustration. Anatomical name: rachis .

Back  -    New Search

baclofen (bak-l-fen) n.

a skeletal muscle relaxant drug administered orally to relieve spasm resulting from injury or disease of the brain or spinal cord, including cerebral palsy and multiple sclerosis. Trade names: Baclospas , Lioresal .

Back  -    New Search

bacteraemia (bak-ter-ee-mi) n.

the presence of bacteria in the blood: a sign of infection.

Back  -    New Search

bacteri-(bacterio-)

prefix denoting bacteria.

Back  -    New Search

bacteria (bak-teer-i) pl. n. (sing. bacterium)

a group of microorganisms all of which lack a distinct nuclear membrane and have a cell wall of unique composition. Most bacteria are unicellular; the cells may be spherical (see COCCUS), rodlike (see BACILLUS), spiral (see SPIRILLUM), commashaped (see VIBRIO) or corkscrew-shaped (see SPIROCHAETE). Generally, they range in size between 0.5 and 5 µm. Motile species bear one or more fine hairs (flagella) arising from their surface. Most bacteria reproduce asexually by simple division of cells; some may reproduce sexually by conjugation. Bacteria live in soil, water, or air or as parasites of man, animals, and plants. Some parasitic bacteria cause diseases by producing poisons (see ENDOTOXIN, EXOTOXIN).
—bacterial adj.

Back  -    New Search

bactericidal (bak-teer-i-sy-dl) adj.

capable of killing bacteria. Substances with this property include antibiotics, antiseptics, and disinfectants. Compare BACTERIOSTATIC
.—bactericide n.

Back  -    New Search

bacteriology (bak-teer-i-ol-ji) n.

the science concerned with the study of bacteria. See also MICROBIOLOGY.
—bacteriological adj. —bacteriologist n.

Back  -    New Search

bacteriolysin (bak-teer-i-ol-i-sin) n.

see LYSIN.

Back  -    New Search

bacteriolysis (bak-teer-i-ol-i-sis) n.

the destruction of bacteria by lysis.
—bacteriolytic adj.

Back  -    New Search

bacteriophage (phage) (bak-teer-i-oh-fayj) n.

a virus that attacks bacteria. The phage grows and replicates in the bacterial cell, which is eventually destroyed with the release of new phages. Each phage acts specifically against a particular species of bacterium. This is utilized in phage typing , a technique of identifying bacteria by the action of known phages on them.

Back  -    New Search

bacteriostatic (bak-teer-i-oh-stat-ik) adj.

capable of inhibiting or retarding the growth and multiplication of bacteria. Compare BACTERICIDAL.

Back  -    New Search

bacterium (bak-teer-im) n.

see BACTERIA.

Back  -    New Search

bacteriuria (bak-teer-i-yoor-i) n.

the presence of bacteria in the urine.

Back  -    New Search

Bactrim (bak-trim) n.

see CO-TRIMOXAZOLE.

Back  -    New Search

bagassosis (bag--soh-sis) n.

a form of external allergic alveolitis caused by exposure to the dust of mouldy bagasse, the residue of sugar cane after the sugar has been extracted. Symptoms include fever, malaise, irritant cough, and respiratory distress.

Back  -    New Search

Baghdad boil (bag-dad) n.

see ORIENTAL SORE.

Back  -    New Search

BAHA n.

bone-anchored hearing aid. see HEARING AID.

Back  -    New Search

Baker's cyst (bay-kerz) n.

a cyst behind the knee resulting from a protrusion of the synovial membrane from a knee joint affected by osteoarthritis. [W. M. Baker (1839–96), British surgeon]

Back  -    New Search

BAL n.

1 see BRONCHOALVEOLAR LAVAGE.

2 British Anti-Lewisite (see DIMERCAPROL).
Top

Back  -    New Search

balanced salt solution (BSS) (bal-nst) n.

a solution made to a physiological pH and having physiological concentrations of salts, including sodium, potassium, calcium, magnesium, and chloride. Such fluids are used during intraocular surgery and to replace intraocular fluids.

Back  -    New Search

balanitis (bal--ny-tis) n.

inflammation of the glans penis, usually associated with tightness of the foreskin (phimosis). b. xerotica obliterans an autoimmune condition characterized by ivory-white patches on the glans.

Back  -    New Search

balanoposthitis (bal--noh-pos-th'y-tis) n.

inflammation of the foreskin and the surface of the underlying glans penis. It usually occurs as a consequence of phimosis and represents a more extensive local reaction than simple balanitis.

Back  -    New Search

balantidiasis (bal-n-ti-dy--sis) n.

an infestation of the large intestine of man with the parasitic protozoan Balantidium coli. The parasite invades and destroys the intestinal wall, causing ulceration and necrosis, and the patient may experience diarrhoea and dysentery.

Back  -    New Search

baldness (bawld-nis) n.

see ALOPECIA.

Back  -    New Search

Balkan beam (Balkan frame) (bawl-kn) n.

a rectangular frame attached over a bed, used for the support of splints, pulleys, or slings for an immobilized limb.

Back  -    New Search

ball-and-cage valve (bawl-nd-kayj) n.

a form of prosthesis commonly used for replacing damaged heart valves.

Back  -    New Search

ball-and-socket joint (bawl-nd-sok-it) n.

see ENARTHROSIS.

Back  -    New Search

balloon (b-loon) n.

an inflatable plastic cylinder of variable size that is mounted on a thin tube and used for dilating narrow areas in blood vessels or in the alimentary tract (strictures). It is also used to prevent reflux of solutions being injected, e.g. into a vessel during angiography. b. angioplasty see ANGIOPLASTY.

Back  -    New Search

ballottement (b-lot-mnt) n.

the technique of examining a fluid-filled part of the body to detect a floating object. During pregnancy, a sharp tap with the fingers, applied to the uterus through the abdominal wall or the vagina, causes the fetus to move away and then return, with an answering tap, to its original position.

Back  -    New Search

balneotherapy (bal-ni-oh-th'e-r-pi) n.

the treatment of disease by bathing, originally in the mineral-containing waters of hot springs. Today, specialized remedial treatment in baths is used to alleviate pain and improve blood circulation and limb mobility in conditions such as arthritis.

Back  -    New Search

balsam (bawl-sm) n.

an aromatic resinous substance of plant origin. b. of Peru a South American balsam used in skin preparations as a mild antiseptic. See FRIAR'S BALSAM.

Back  -    New Search

bandage (band-ij) n.

a piece of material, in the form of a pad or strip, applied to a wound or bound around an injured or diseased part of the body.

Back  -    New Search

Bandl's ring (ban-d'lz) n.

an abnormal retraction ring (see RETRACTION) that occurs in obstructed labour. It is a sign of impending rupture of the lower segment of the uterus, which becomes progressively thinner as Bandl's ring rises upwards. Immediate action to relieve the obstruction is then necessary, usually in the form of Caesarean section. [L. Bandl (1842–92), German obstetrician]

Back  -    New Search

Bankart's operation (bank-arts) n.

an operation to repair a defect in the glenoid cavity in cases of recurrent dislocation of the shoulder. [A. S. B. Bankart (1879–1951), British orthopaedic surgeon]

Back  -    New Search

Banti's syndrome (ban-teez) n.

a disorder in which enlargement and overactivity of the spleen occurs as a result of increased pressure within the splenic vein. The commonest cause is cirrhosis of the liver. [G. Banti (1852–1925), Italian pathologist]

Back  -    New Search

barbiturate (bar-bit-yoor-t) n.

any of a group of drugs, derived from barbituric acid, that depress activity of the central nervous system. Because barbiturates produce psychological and physical dependence and have serious toxic side-effects (see BARBITURISM), their use as sleeping pills has declined, although they are still used to induce anaesthesia (see THIOPENTONE) and to control epilepsy (see PHENOBARBITONE).

Back  -    New Search

barbiturism (bar-bit-yoor-izm) n.

addiction to drugs of the barbiturate group. Signs of intoxication include slurring of speech, sleepiness, and loss of balance. Withdrawal of the drugs must be undertaken slowly.

Back  -    New Search

barbotage (bar-b-tahzh) n.

a method of spinal anaesthesia in which a small amount of anaesthetic is injected into the subarachnoid space followed by withdrawal of cerebrospinal fluid into the syringe. This process is repeated until all the anaesthetic has been injected.

Back  -    New Search

barium sulphate (bair-im) n.

a barium salt, insoluble in water, that is opaque to X-rays and is used as a contrast medium in radiography of the stomach and intestines. See also ENEMA.

Back  -    New Search

Barlow's disease (bar-lohz) n.

infantile scurvy: scurvy occurring in young children due to dietary deficiency of vitamin C. [Sir T. Barlow (1845–1945), British physician]

Back  -    New Search

Barlow's sign n.

a sign used in a test for congenital dislocation of the hip. A clunk felt and sometimes heard on manual flexion and abduction of the joint indicates instability of the joint.

Back  -    New Search

baroreceptor (baroceptor) (ba-roh-ri-sep-ter) n.

a collection of sensory nerve endings specialized to monitor changes in blood pressure. The main receptors lie in the carotid sinuses and the aortic arch.

Back  -    New Search

Barr body (bar) n.

see SEX CHROMATIN. [M. L. Barr (1908– ), Canadian anatomist]

Back  -    New Search

Barrett's oesophagus (ba-rts) n.

a condition in which the normal squamous epithelium lining the oesophagus is replaced by columnar epithelium because of damage caused by gastro-oesophageal reflux or (rarely) by corrosive oesophagitis. The condition may be associated with an ulcer (Barrett's ulcer ). [N. R. Barrett (1903–79), British surgeon]

Back  -    New Search

barrier cream (ba-ri-er) n.

a preparation used to protect the skin against water-soluble irritants (e.g. detergents, breakdown products of urine). Usually applied in the form of a cream or ointment and often containing a silicone (e.g. dimethicone), barrier creams are useful in the alleviation of various skin disorders, including napkin rash and bedsores.

Back  -    New Search

barrier nursing n.

the nursing care of an infectious patient in isolation from other patients, to prevent the spread of infection.

Back  -    New Search

bartholinitis (vulvovaginitis) (bar-th-li-ny-tis) n.

inflammation of Bartholin's glands. acute b. bartholinitis in which abscess formation may occur (Bartholin's abscess ). chronic b. bartholinitis in which cysts may form in the glands as a result of blockage of their ducts.

Back  -    New Search

Bartholin's glands (greater vestibular glands) (bar-th-linz) pl. n.

a pair of glands that open at the junction of the vagina and the vulva. Their secretions lubricate the vulva and so assist penetration by the penis during coitus. [C. Bartholin (1655–1748), Danish anatomist]

Back  -    New Search

basal cell carcinoma (BCC) (bay-sl) n.

the commonest form of skin cancer: a slow-growing tumour that usually occurs on the central area of the face, especially in fair-skinned people. The prevalence increases greatly with exposure to sunlight. Treatment involves curettage and cautery, surgical excision, cryotherapy, or radiotherapy. If neglected for decades, a BCC eventually becomes a rodent ulcer and destroys the surrounding tissue. The term ‘rodent ulcer’ is sometimes used to mean any basal cell carcinoma.

Back  -    New Search

basal ganglia pl. n.

several large masses of grey matter embedded deep within the white matter of the cerebrum. They include the caudate nuclei and lenticular nuclei (together known as the corpus striatum ) and the amygdaloid nucleus . The lenticular nucleus consists of the putamen pallidus and globus pallidus . The basal ganglia are involved with the regulation of voluntary movements at a subconscious level.

Back  -    New Search

basal metabolism n.

the minimum amount of energy expended by the body to maintain vital processes, e.g. respiration, circulation, and digestion. It is expressed in terms of heat production per unit of body surface area per day (basal metabolic rate — BMR ). BMR is normally determined indirectly, by measuring the respiratory quotient. Measurements are best taken during a period of least activity, i.e. during sleep and 12–18 hours after a meal, under controlled temperature conditions.

Back  -    New Search

basal narcosis n.

preliminary unconsciousness induced in a patient by administration of a narcotic drug prior to administration of a general anaesthetic by inhalation.

Back  -    New Search

base (bayss) n.

1 the main ingredient of an ointment or other medicinal preparation.

2 a substance that releases hydroxyl ions when dissolved in water, has a pH greater than 7 and turns litmus paper blue, and reacts with an acid to form a salt and water only. Compare ACID.
Top

Back  -    New Search

basement membrane (bayss-mnt) n.

the thin delicate membrane that lies at the base of an epithelium.

Back  -    New Search

basilar artery (ba-si-ler) n.

an artery in the base of the brain, formed by the union of the two vertebral arteries.

Back  -    New Search

basilic vein (b-zil-ik) n.

a large vein in the arm, extending from the hand along the back of the forearm, then passing forward to the inner side of the arm at the elbow.

Back  -    New Search

basophil (bay-s-fil) n.

a variety of white blood cell distinguished by the presence in its cytoplasm of coarse granules that stain purple-black with Romanowsky stains. Basophils are capable of ingesting foreign particles and contain histamine and heparin.

Back  -    New Search

basophilia (bay-s-fil-i) n.

1 a property of a microscopic structure whereby it shows an affinity for basic dyes.

2 an increase in the number of basophils in the blood.
Top

—basophilic adj.

Back  -    New Search

Batchelor plaster (ba-ch-ler) n.

a type of plaster that keeps both legs abducted and medially rotated, used to correct congenital dislocation of the hip. [J. S. Batchelor (1905– ), British orthopaedic surgeon]

Back  -    New Search

Batten's disease (bat-t'nz) n.

a rare hereditary disorder of lipid metabolism. Fatty substances accumulate in the cells of the nervous system, causing progressive dementia, epilepsy, spasticity, and visual failure. The condition starts in late infancy or childhood. [F. E. Batten (1865–1918), British neurologist]

Back  -    New Search

battered baby syndrome (bat-erd) n.

see NONACCIDENTAL INJURY.

Back  -    New Search

battledore placenta (bat-t'l-dor) n.

a placenta to which the umbilical cord is attached at the margin (rather than at the centre).

Back  -    New Search

Bazin's disease (ba-zanz) n.

a rare disease of young women in which tender nodules develop under the skin in the calves. The nodules may break down and ulcerate though they may clear up spontaneously. Medical name: erythema induratum . [A. P. E. Bazin (1807–78), French dermatologist]

Back  -    New Search

BCC n.

see BASAL CELL CARCINOMA.

Back  -    New Search

B-cell n.

see LYMPHOCYTE.

Back  -    New Search

BCG (bacille Calmette-Guérin) n.

a strain of tubercle bacillus that has lost the power to cause tuberculosis but retains its antigenic activity; it is therefore used to prepare a vaccine against the disease.

Back  -    New Search

bearing down (bair-ing down) n.

1 the expulsive uterine contractions of a woman in the second stage of labour.

2 a sensation of heaviness and descent in the pelvis associated with pelvic tumours and certain other disorders.
Top

Back  -    New Search

Becker muscular dystrophy (bek-er) n.

a sex-linked (X-linked) disorder in which affected males develop an increase in muscle size followed by weakness and wasting. It usually starts between the ages of 5 and 15, and 25 years after onset most patients are wheelchair-bound. Although most men become severely disabled, life expectancy is close to normal. The disorder is similar to Duchenne muscular dystrophy but less severe. [P. E. Becker (1908– ), German geneticist]

Back  -    New Search

beclomethasone (bek-loh-meth-a-zohn) n.

a corticosteroid drug that is administered by inhaler to treat hay fever and asthma and is applied externally in the treatment of inflammatory skin disorders. Trade names: Beconase , Becotide , Propaderm .

Back  -    New Search

becquerel (bek-er-el) n.

the SI unit of activity of a radioactive source, being the activity of a radionuclide decaying at a rate of one spontaneous nuclear transition per second. It has replaced the curie. Symbol: Bq.

Back  -    New Search

bed bug (bed bug) n.

a bloodsucking insect of the genus Cimex, especially C. lectularius. They live and lay their eggs in the crevices of walls and furniture and emerge at night to suck blood; their bites leave a route for bacterial infection.

Back  -    New Search

bed occupancy n.

the number of hospital beds occupied by patients expressed as a percentage of the total beds available in the ward, specialty, hospital, area, or region. It is used to assess the demands for hospital beds and hence to gauge an appropriate balance between health needs and residential (hospital) resources.

Back  -    New Search

bedsore (decubitus ulcer, pressure sore) (bed-sor) n.

an ulcerated area of skin caused by continuous pressure on part of the body in a bedridden patient. Careful nursing is necessary to prevent local gangrene. The patient's position should be changed frequently, and the buttocks, heels, elbows, and other regions at risk kept dry and clean.

Back  -    New Search

bedwetting (bed-wet-ing) n.

see ENURESIS.

Back  -    New Search

behavioural objective (bi-hayv-yer-l) n.

the goal of a particular nursing intervention or a specific lesson, in terms of what a person is expected to be able to do as a result of it.

Back  -    New Search

behaviourism (bi-hayv-yer-izm) n.

an approach to psychology postulating that only observable behaviour need be studied, thus denying any importance to unconscious processes.
—behaviourist n.

Back  -    New Search

behaviour therapy (bi-hayv-yer) n.

treatment based on the belief that psychological problems are the products of faulty learning and not the symptoms of an underlying disease. See also AVERSION THERAPY, CONDITIONING, DESENSITIZATION, EXPOSURE, RESPONSE PREVENTION.

Back  -    New Search

Behçet's syndrome (bay-setz) n.

a recurrent disease, involving many body systems, characterized by oral and genital ulcerations and inflammation of the iris; skin lesions occur in most cases. It may also involve the joints and cause inflammation of the veins. The condition, whose cause is unknown, occurs more often in men. [H. Behçet (1889–1948), Turkish dermatologist]

Back  -    New Search

bejel (endemic syphilis) (bej-l) n.

a long-lasting nonvenereal form of syphilis, particularly prevalent where standards of personal hygiene are low. The disease is spread among children and adults by direct body contact.

Back  -    New Search

belladonna (bel--don-) n.

1 deadly nightshade (Atropa belladonna).

2 the poisonous alkaloid derived from deadly nightshade, from which atropine is extracted. Preparations of belladonna are used as an anticholinergic drug (see PARASYMPATHOLYTIC). Trade names: Alophen , Bellocarb .
Top

Back  -    New Search

belle indifférence (bel an-di-fay-rahns) n.

a symptom of conversion disorder in which an apparently grave physical affliction (which has no physical cause) is accepted in a calm and smiling fashion.

Back  -    New Search

Bellocq's cannula (Bellocq's sound) (bel-oks) n.

a curved hollow tube used for inserting a plug into the nose to arrest nosebleeding. [J. J. Bellocq (1732–1807), French surgeon]

Back  -    New Search

Bell's palsy (belz) n.

paralysis of the facial nerve causing weakness of the muscles of one side of the face and an inability to close the eye. [Sir C. Bell (1774–1842), Scottish physiologist]

Back  -    New Search

belly (bel-i) n.

1 the abdomen or abdominal cavity.

2 the central fleshy portion of a muscle.
Top

Back  -    New Search

Bence-Jones protein (Bence-Jones albumose) (benss-joh'nz) n.

a protein of low molecular weight found in the urine of patients with multiple myeloma and rarely in patients with lymphoma, leukaemia, and Hodgkin's disease. [H. Bence-Jones (1814–73), British physician]

Back  -    New Search

bendrofluazide (bendroflumethazide) (ben-droh-floo--zyd) n.

a potent thiazide diuretic used in the treatment of conditions involving retention of fluid, such as hypertension and oedema. Trade names: Aprinox , Contyl .

Back  -    New Search

bends (bendz) n.

see COMPRESSED AIR ILLNESS.

Back  -    New Search

Benedict's test (ben-i-dikts) n.

a test for the presence of sugar in urine or other liquids, using a solution of sodium or potassium citrate, sodium carbonate, and copper sulphate (Benedict's solution ). [S. R. Benedict (1884–1936), US chemist]

Back  -    New Search

beneficence (bi-nef-i-sns) n.

(in health care) the duty to do good and avoid doing harm to other people, which includes acting to promote their interests and protecting the weak and vulnerable. It includes the duty of advocacy (see ADVOCATE).

Back  -    New Search

benethamine penicillin (ben-eth--min)n.

an antibiotic, derived from penicillin G, effective against most Gram-positive bacteria.

Back  -    New Search

benign (bi-nyn) adj.

1 describing a tumour that is not cancerous.

2 describing any disorder or condition that does not produce harmful effects. Compare MALIGNANT.
Top

Back  -    New Search

benign prostatic hypertrophy (BPH) n.

see PROSTATE GLAND.

Back  -    New Search

benorylate (ben-or-il-ayt) n.

a compound of aspirin and paracetamol that relieves pain, inflammation, and fever. It is an alternative to aspirin, particularly in the treatment of rheumatoid arthritis. Trade name: Benoral .

Back  -    New Search

benperidol (ben-pe-ri-dol) n.

a butyrophenone antipsychotic drug used mainly to treat deviant and antisocial sexual behaviour. It is administered by mouth. Trade name: Anquil .

Back  -    New Search

benserazide (ben-ser--zyd) n.

a drug administered by mouth in combination with levodopa (as Madopar ) to treat parkinsonism following encephalitis (post-encephalitic parkinsonism).

Back  -    New Search

benzalkonium (ben-zl-koh-nim) n.

a detergent disinfectant with the same uses and effects as cetrimide.

Back  -    New Search

benzathine penicillin (ben-z-theen) n.

a long-acting antibiotic, given by mouth or intramuscular injection, that is effective against most Gram-positive bacteria (streptococci, staphylococci, and pneumococci). Trade name: Penidural . See also PENICILLIN.

Back  -    New Search

benzene (ben-zeen) n.

a toxic liquid hydrocarbon. Continued inhalation of benzene vapour may result in aplastic anaemia or a form of leukaemia. Formula:
C_6H_6
.

Back  -    New Search

benzhexol (benz-heks-ol) n.

a drug that acts in a similar way to atropine. Taken by mouth, it is used mainly to reduce muscle spasm in parkinsonism. Trade names: Artane , Broflex .

Back  -    New Search

benzocaine (ben-zoh-kayn) n.

a local anaesthetic applied externally to relieve painful conditions of the skin and mucous membranes. Virtually nontoxic, it can also be administered orally to treat mouth lacerations or gastric ulcers.

Back  -    New Search

benzodiazepines (ben-zoh-dy-az--peenz) pl. n.

a group of minor tranquillizers and hypnotics, including bromazepam, diazepam, and oxazepam.

Back  -    New Search

benzoic acid (ben-zoh-ik) n.

an antiseptic used as a preservative and to treat fungal infections of the skin.

Back  -    New Search

benzoin (ben-zoh-in) n.

a fragrant gum resin used as a constituent of friar's balsam.

Back  -    New Search

benzoyl peroxide (ben-zoh-il p-rok-syd) n.

a preparation administered as a cream, lotion, or gel in the treatment of acne and other skin conditions. It removes the surface layers of the epidermis, unblocks skin pores, and has an antiseptic effect on skin bacteria. Trade names: Acetoxyl , Acnegel , Benoxyl .

Back  -    New Search

benzthiazide (benz-th'y--zyd) n.

a diuretic used in the treatment of conditions involving fluid retention. Trade name: Dytide .

Back  -    New Search

benztropine (benz-tr-peen) n.

a drug similar to atropine, used mainly in the treatment of parkinsonism to reduce rigidity and muscle cramps.

Back  -    New Search

benzydamine hydrochloride (ben-zy-da-meen hy-droh-klor-ryd) n.

an antiinflammatory drug (see NSAID) used to treat muscle pain. It is administered as a cream for external use. Trade name: Difflam .

Back  -    New Search

benzyl benzoate (ben-zyl ben-zoh-ayt) n.

an oily aromatic liquid that is applied externally for the treatment of scabies. Trade name: Ascabiol .

Back  -    New Search

benzylpenicillin (ben-zyl-pen-i-sil-in) n.

see PENICILLIN.

Back  -    New Search

bephenium hydroxynaphthoate (b'e-fen-im hy-droks-i-naf-thoh-ayt) n.

an anthelmintic drug used to eliminate hookworms and other nematodes. It is administered by mouth. Trade name: Alcopar .

Back  -    New Search

beriberi (b'e-ri-b'e-ri) n.

a nutritional disorder due to deficiency of vitamin B_1 (thiamin). It is widespread in communities in which the diet is based on polished rice. dry b. a form of beriberi in which there is extreme emaciation. wet b. a form of beriberi in which there is an accumulation of tissue fluid (oedema). There is nervous degeneration in both forms of the disease and death from heart failure is often the outcome.

Back  -    New Search

berry aneurysm (b'e-ri) n.

see ANEURYSM.

Back  -    New Search

berylliosis (b'e-ri-li-oh-sis) n.

poisoning by beryllium or its compounds, either by inhalation or by skin contamination. Inhalation of fumes from molten beryllium causes an acute alveolitis and is usually fatal. Subacute and chronic forms can result from exposure to the powder and can produce granulomata in the skin or lungs. In the lungs, these can lead to fibrosis unless prevented by prompt use of oral corticosteroids.

Back  -    New Search

Best's disease (bests) n.

see VITELLIFORM DEGENERATION.[F. Best (1878–1920), German physician]

Back  -    New Search

beta blocker (bee-t) n.

a drug, such as oxprenolol or propranolol, that prevents stimulation of the beta-adrenergic receptors at the nerve endings of the sympathetic nervous system and therefore decreases the activity of the heart.

Back  -    New Search

beta cells pl. n.

the cells of the islets of Langerhans that produce insulin. Compare ALPHA CELLS.

Back  -    New Search

betahistine (bee-t-hist-een) n.

a drug that is an analogue of histamine and increases blood flow through the inner ear. It is administered by mouth to treat Ménière's disease. Trade name: Serc .

Back  -    New Search

betamethasone (bee-t-meth--sohn) n.

a synthetic corticosteroid drug with effects and uses similar to those of prednisolone. The side-effects are those of cortisone. Trade names: Betnelan , Betnesol , Betnovate .

Back  -    New Search

betatron (bee-t-tron) n.

a device used to accelerate a stream of electrons (beta particles ) into a beam of radiation that can be used in radiotherapy.

Back  -    New Search

betaxolol (bet-aks-oh-lol) n.

a beta blocker drug used to treat high blood pressure and chronic simple glaucoma. It is administered by mouth and as eye drops. Trade names: Kerlone , Betoptic .

Back  -    New Search

bethanechol (beth-an--kol) n.

a cholinergic drug (see PARASYMPATHOMIMETIC) that acts mainly on the bowel and bladder, stimulating these organs to empty. It is administered by mouth. Trade name: Myotonine .

Back  -    New Search

bethanidine (beth-an-i-deen) n.

a drug that is administered orally to lower blood pressure.

Back  -    New Search

bezafibrate (bee-z-fy-brayt) n.

a drug that reduces blood cholesterol levels and is used to treat hypercholesterolaemia that fails to respond to diet. It is administered by mouth. Trade name: Bezalip .

Back  -    New Search

bezoar (bee-zor) n.

a mass of swallowed foreign material within the stomach.

Back  -    New Search

bi-prefix

denoting two; double.

Back  -    New Search

bicarbonate (by-kar-b-nit) n.

a salt containing the ion
HCO_3-
. b. of soda see SODIUM BICARBONATE.

Back  -    New Search

biceps (by-seps) n.

a muscle with two heads. b. brachii a muscle that extends from the shoulder to the elbow and is responsible for flexing the arm and forearm. b. femoris a muscle at the back of the thigh, responsible for flexing the knee.

Back  -    New Search

biconcave (by-kon-kayv) adj.

having a hollowed surface on both sides. Biconcave lenses are used to correct short-sightedness. Compare BICONVEX.

Back  -    New Search

biconvex (by-kon-veks) adj.

having a surface on each side that curves outwards. Biconvex lenses are used to correct long-sightedness. Compare BICONCAVE.

Back  -    New Search

bicornuate (by-kor-new-it) adj.

having two hornlike processes or projections. The term is applied to an abnormal uterus that is divided into two separate halves at the upper end.

Back  -    New Search

bicuspid (by-kus-pid) adj.

having two cusps, as in the premolar teeth and the mitral valve of the heart. b. valve see MITRAL VALVE.

Back  -    New Search

bifid (by-fid) adj.

split or cleft into two parts.

Back  -    New Search

bifocal lenses (by-foh-kl) pl. n.

glasses in which the upper part of the lens gives a sharp image of distant objects and the lower part is for near vision, such as reading. See also MULTIFOCAL LENSES.

Back  -    New Search

bifurcation (by-fer-kay-shn) n.

(in anatomy) the point at which division into two branches occurs; for example in blood vessels or in the trachea.

Back  -    New Search

bigeminy (by-jem-ini) n.

the condition in which alternate ectopic beats of the heart are transmitted to the pulse and felt as a double pulse beat (pulsus bigeminus ).

Back  -    New Search

biguanide (by-gwah-nyd) n.

any of a class of drugs that increase glucose uptake by the muscles and reduce glucose release by the liver. These drugs, which include metformin, are taken by mouth in the treatment of diabetes mellitus.

Back  -    New Search

bilateral (by-lat-er-l) adj.

(in anatomy) relating to or affecting both sides of the body or of a tissue or organ or both of a pair of organs.

Back  -    New Search

bile (byl) n.

a thick alkaline fluid that is secreted by the liver and stored in the gall bladder. It is ejected intermittently into the duodenum, where it helps to emulsify fats so that they can be more easily digested. Bile may be yellow, green, or brown; its constituents include bile pigments and salts, lecithin, and cholesterol.

Back  -    New Search

bile acids pl. n.

the organic acids in bile; mostly occurring as bile salts. They are cholic acid, deoxycholic acid, glycocholic acid, and taurocholic acid.

Back  -    New Search

bile duct n.

any of the ducts that convey bile from the liver. Many small ducts unite to form the main bile duct, the hepatic duct . This joins the cystic duct , which leads from the gall bladder, to form the common bile duct , which drains into the duodenum.

Back  -    New Search

bile pigments pl. n.

coloured compounds – breakdown products of the blood pigment haemoglobin — that are excreted in bile. The two most important bile pigments are bilirubin , which is orange or yellow, and its oxidized form biliverdin , which is green. Mixed with the intestinal contents, they give the brown colour to the faeces (see UROBILINOGEN).

Back  -    New Search

bile salts pl. n.

sodium glycocholate and sodium taurocholate – the alkaline salts of bile – necessary for the emulsification of fats.

Back  -    New Search

Bilharzia (bil-harts-i) n.

see SCHISTOSOMA.

Back  -    New Search

bilharziasis (bil-harts-l--sis) n.

see SCHISTOSOMIASIS.

Back  -    New Search

bili- prefix

denoting bile.

Back  -    New Search

biliary (bil-yer-i) adj.

relating to or affecting the bile duct or bile. b. colic severe steady pain in the upper abdomen (in the mid-line or to the right) resulting from obstruction of the gall bladder or common bile duct, usually by a stone. Vomiting often occurs simultaneously. b. fistula see FISTULA.

Back  -    New Search

bilious (bil-ys) adj.

1 containing bile.

2 a lay term used to describe attacks of nausea or vomiting.
Top

Back  -    New Search

bilirubin (bili-roo-bin) n.

see BILE PIGMENTS.

Back  -    New Search

biliuria (choluria) (bili-yoor-i) n.

the presence of bile in the urine: a feature of certain forms of jaundice.

Back  -    New Search

biliverdin (bili-ver-din) n.

see BILE PIGMENTS.

Back  -    New Search

Billings method (bil-ingz) n.

a method of planning pregnancy, now rarely used, involving the daily examination of cervical mucus in the vagina, which varies in consistency and colour throughout the menstrual cycle. [J. and E. Billings (20th century)]

Back  -    New Search

Billroth's operation (bil-rohts) n.

an operation in which the lower part of the stomach is removed and the remaining portion joined to the duodenum (B. o. I ) or the lower stomach and duodenum are removed, with attachment of the remaining stomach to the jejunum (B. o. II ). See GASTRECTOMY. [C. A. T. Billroth (1829–94), Austrian surgeon]

Back  -    New Search

bimanual (by-man-yoo-l) adj.

using two hands to perform an activity, such as a gynaecological examination.

Back  -    New Search

binaural (byn-or-l) adj.

relating to or involving the use of both ears.

Back  -    New Search

binder (byn-der) n.

a bandage that is wound around a part of the body, usually the abdomen, to apply pressure or to give support or protection.

Back  -    New Search

binge-purge syndrome (binj-perj) n.

see BULIMIA.

Back  -    New Search

binocular (bin-ok-yoo-ler) adj.

relating to or involving the use of both eyes. b. vision the acquired ability to focus both eyes on an object at the same time, so that only one image is seen.

Back  -    New Search

binovular (bin-ov-yoo-ler) adj.

derived from two separate ova, as are fraternal twins. Compare UNIOVULAR.

Back  -    New Search

bio- prefix

denoting life or living organisms.

Back  -    New Search

bioassay (by-oh-ass-ay) n.

estimation of the activity or potency of a drug or other substance by comparing its effects on living organisms with effects of a preparation of known strength.

Back  -    New Search

bioavailability (by-oh--vayl--bil-iti) n.

the proportion of a drug that is delivered to its site of action in the body. This is usually the amount entering the circulation and may be low when the drugs are given by mouth.

Back  -    New Search

biochemistry (by-oh-kem-istri) n.

the study of the chemical processes and substances occurring in living things.
—biochemical adj. —biochemist n.

Back  -    New Search

bioengineering (by-oh-en-ji-neer-ing) n.

the application of biological and engineering principles to the development and manufacture of equipment and devices for use in biological systems. Examples of such products include orthopaedic prostheses and heart pacemakers.

Back  -    New Search

biogenesis (by-oh-jen-i-sis) n.

the theory that living organisms can arise only from other living organisms and not from non-living matter.

Back  -    New Search

biology (by-ol-ji) n.

the study of living organisms including their structure and function and their relationships with one another and with the inanimate world.
—biological (by--loj-ik-l) adj. —biologist n.

Back  -    New Search

bionics (by-on-iks) n.

the science of mechanical or electronic systems that function in the same way as, or have characteristics of, living systems. Compare CYBERNETICS.
—bionic adj.

Back  -    New Search

bionomics (by--nom-iks) n.

see ECOLOGY.

Back  -    New Search

biophysical profile (by-oh-fiz-iklproh-fyl) n.

a physiological assessment of fetal wellbeing, including ultrasound scans, cardiographs, and fetal movements.

Back  -    New Search

biopsy (by-op-si) n.

the removal of a small piece of living tissue from an organ or part of the body for microscopic examination.

Back  -    New Search

biostatistics (by-oh-st-tist-iks) n.

statistical information and techniques used with special reference to studies of health and social problems. See also DEMOGRAPHY, VITAL STATISTICS.

Back  -    New Search

biotin (by--tin) n.

a vitamin of the B complex that is essential for the metabolism of fat, being involved in fatty acid synthesis and gluconeogenesis. Rich sources of the vitamin are egg yolk, yeast, and liver.

Back  -    New Search

biphosphonates (by-fos-f-nayts) pl. n.

a group of drugs that inhibit the resorption of bone by blocking the action of osteoclasts. They include etidronate (Didronel) and pamidronate (Aredia), which are used to treat various disorders of bone metabolism, including Paget's disease; and alendronate (Fosamax), which has been successful in the treatment of osteoporosis by preventing bone loss and increasing bone density.

Back  -    New Search

bipolar (by-poh-ler) adj.

(in neurology) describing a neurone (nerve cell) that has two processes extending in different directions from its cell body.

Back  -    New Search

bipolar disorder n.

see MANIC-DEPRESSIVE PSYCHOSIS.

Back  -    New Search

bird-fancier's lung (berd-fan-si-erz) n.

a form of external allergic alveolitis caused by the inhalation of avian proteins present in the droppings and feathers of certain birds, especially pigeons and caged birds (such as budgerigars). There is an acute and a chronic form. See also ALVEOLITIS.

Back  -    New Search

birth (berth) n.

(in obstetrics) see LABOUR.

Back  -    New Search

birth control n.

the use of contraception or sterilization (male or female) to prevent unwanted pregnancies.

Back  -    New Search

birthing chair (berth-ing) n.

a chair specially adapted to allow childbirth to take place in a sitting position. Its recent introduction in the Western world followed the increasing demand by women for greater mobility during labour. The chair is electronically powered and can be tilted back quickly and easily should the need arise.

Back  -    New Search

birthmark (berth-mark) n.

a skin blemish or mark present at birth.

Back  -    New Search

birth rate (live birth rate) n.

the number of live births occurring in a year per 1000 total population. See also FERTILITY RATE.

Back  -    New Search

bisacodyl (bis-ak-oh-dil) n.

a laxative that acts on the large intestine to cause reflex movement and bowel evacuation. It is administered by mouth or in a suppository. Trade name: Dulco-lax .

Back  -    New Search

bisexual (by-seks-yoo-l) adj.

1 describing an individual who is sexually attracted to both men and women.

2 describing an individual who possesses the qualities of both sexes.
Top

Back  -    New Search

bismuth (biz-mth) n.

a white metallic element. Its salts are used in some antacid mixtures and as protective agents in skin powders and pastes. They were formerly widely used in the treatment of syphilis. Symbol: Bi.

Back  -    New Search

bismuth carbonate (kar-bn-ayt) n.

a drug used to treat peptic ulcer, especially cases in which the bacterium Helicobacter pylori is a causal agent. It is administered by mouth. Trade name: APP .

Back  -    New Search

bisoprolol (by-soh-proh-lol) n.

a beta blocker drug used to treat angina pectoris. It is administered by mouth. Trade names: Emcor , Monocor .

Back  -    New Search

bistoury (bis-ter-i) n.

a narrow surgical knife, with a straight or curved blade.

Back  -    New Search

bite-wing (byt-wing) n.

a dental X-ray film that provides a view of the crowns of the teeth in part of both upper and lower jaws.

Back  -    New Search

Bitot's spots (bee-tohz) pl. n.

cheesy foamy greyish spots that form on the surface of dry patches of conjunctiva at the sides of the eyes. They consist of fragments of keratinized epithelium. A common cause is vitamin A deficiency. [P. A. Bitot (1822–88), French physician]

Back  -    New Search

bivalve (by-valv) adj.

consisting of or possessing two valves or sections. b. cast a plaster cast that is cut into anterior and posterior sections to monitor pressure beneath the cast. b. speculum a vaginal speculum that has two blades.

Back  -    New Search

black eye (blak) n.

bruising of the eyelids.

Back  -    New Search

blackhead (blak-hed) n.

a plug formed of fatty material (sebum and keratin) in the outlet of a sebaceous gland in the skin. See also ACNE. Medical name: comedo .

Back  -    New Search

black heel n.

a black area, usually over the Achilles tendon, resulting from the rupture of capillaries in the skin in those who play basketball, squash, etc. It may be mistaken for malignant melanoma.

Back  -    New Search

blackwater fever (blak-waw-ter) n.

a rare and serious complication of malignant tertian (falciparum) malaria in which there is massive destruction of the red blood cells, leading to the presence of the blood pigment haemoglobin in the urine.

Back  -    New Search

bladder (blad-er) n.

1 (urinary bladder) a sac-shaped organ that has a wall of smooth muscle and stores the urine produced by the kidneys.

2 any of several other hollow organs containing fluid, such as the gall bladder.
Top

Back  -    New Search

bladderworm (blad-er-werm) n.

see CYSTICERCUS.

Back  -    New Search

Blalock-Taussig operation (blay-loktaw-sig) n.

an operation in which the pulmonary artery is anastomosed to the subclavian artery, performed on patients with tetralogy of Fallot. [A. Blalock (1899–1964), US surgeon; H. B. Taussig (20th century), US paediatrician]

Back  -    New Search

bland (bland) adj.

nonirritating; mild; soothing: applied to foods and diets.

Back  -    New Search

blast (blahst) n.

an important cause of serious soft-tissue injury that is associated with explosions or high-velocity missiles. The eardrums, lungs, and gastrointestinal tract are especially vulnerable to the indirect effects of the blast wave.

Back  -    New Search

-blast suffix

denoting a formative cell.

Back  -    New Search

blasto- prefix

denoting a germ cell or embryo.

Back  -    New Search

blastocyst (blast-oh-sist) n.

an early stage of embryonic development that consists of a hollow ball of cells with a localized thickening (the inner cell mass ) that will develop into the actual embryo. See also IMPLANTATION.

Back  -    New Search

blastomycosis (blast-oh-my-koh-sis) n.

any disease caused by parasitic fungi of the genus Blastomyces, which may affect the skin (forming wartlike ulcers and tumours) or involve various internal tissues.

Back  -    New Search

blastula (blast-yoo-l) n.

an early stage of the embryonic development of many animals. The equivalent stage in mammals (including man) is the blastocyst.

Back  -    New Search

bleb (bleb) n.

a blister or large vesicle. filtering b. a blister-like cyst underneath the conjunctiva resulting from trabeculectomy, a surgical procedure commonly used in the treatment of glaucoma.

Back  -    New Search

bleeding (bleed-ing) n.

see HAEMORRHAGE.

Back  -    New Search

bleeding time n.

the time taken for bleeding to cease from a small wound, such as a puncture in a finger or ear lobe. It is used as a test of platelet function.

Back  -    New Search

blenn- (blenno-) prefix

denoting mucus.

Back  -    New Search

blennorrhagia (blen--ray-ji) n.

a copious discharge of mucus, particularly from the urethra.

Back  -    New Search

blennorrhoea (blen--ree-) n.

a profuse watery discharge from the urethra.

Back  -    New Search

bleomycin (bli-oh-my-sin) n.

an antibiotic with action against cancer cells, administered by injection in the treatment of Hodgkin's disease and other lymphomas and in squamous cell carcinoma.

Back  -    New Search

blephar- (blepharo-) prefix

denoting the eyelid.

Back  -    New Search

blepharitis (blef--ry-tis) n.

inflammation of the eyelids.

Back  -    New Search

blepharochalasis (blef-er-oh-k-lay-sis) n.

excessive eyelid skin resulting from recurrent episodes of oedema and inflammation of the eyelid. It occurs in young people, causing drooping of the lid. Compare DERMATOCHALASIS.

Back  -    New Search

blepharoconjunctivitis (blef-er-oh-kn-junk-ti-vy-tis) n.

inflammation involving the eyelid margins and conjunctiva.

Back  -    New Search

blepharon (blef-er-n) n.

see EYELID.

Back  -    New Search

blepharoptosis (blef-er-op-t-sis) n.

see PTOSIS.

Back  -    New Search

blepharospasm (blef-er-oh-spazm) n.

involuntary tight contraction of the eyelids, either in response to painful conditions of the eye or as a form of dystonia.

Back  -    New Search

blind loop syndrome (stagnant loop syndrome) (blynd) n.

a condition of stasis of the small intestine allowing the overgrowth of bacteria, which causes malabsorption and the passage of fatty stools (see STEATORRHOEA). It is usually the result of chronic obstruction, surgical bypass operations producing a stagnant length of bowel, or conditions in which a segment of intestine is out of continuity with the rest.

Back  -    New Search

blindness (blynd-nis) n.

the inability to see. For administrative purposes, the term also covers cases of partial blindness (see BLIND REGISTER). The commonest causes of blindness worldwide are trachoma, onchocerciasis, and vitamin A deficiency, and in Great Britain age-related macular degeneration, glaucoma, cataract, myopic retinal degeneration, and diabetic retinopathy. See also COLOUR BLINDNESS, DAY BLINDNESS, NIGHT BLINDNESS, SNOW BLINDNESS.

Back  -    New Search

blind register n.

(in Britain) a list of persons who are technically blind due to reduced visual acuity or who have severely restricted fields of vision.

Back  -    New Search

blind spot n.

the small area of the retina of the eye where the nerve fibres from the light-sensitive cells lead into the optic nerve. There are no rods or cones in this area and hence it does not register light. Anatomical name: punctum caecum .

Back  -    New Search

blister (blis-ter) n.

a swelling containing watery fluid (serum) and sometimes also blood (blood b. ) or pus, within or just beneath the skin.

Back  -    New Search

block (blok) n.

any interruption of physiological or mental function, brought about intentionally (as part of a therapeutic procedure) or by disease. See also HEART BLOCK, NERVE BLOCK.

Back  -    New Search

blood (blud) n.

a fluid that circulates throughout the body, via the arteries and veins, providing a vehicle by which an immense variety of different substances are transported between the various organs and tissues. It is composed of cells (see BLOOD CELL), which are suspended in a liquid medium (see PLASMA).

Back  -    New Search

blood bank n.

a department within a hospital or blood transfusion centre in which blood collected from donors is stored prior to transfusion.

Back  -    New Search

blood-brain barrier n.

the mechanism whereby the circulating blood is kept separate from the tissue fluids surrounding the brain cells. It is a semipermeable membrane allowing solutions to pass through it but excluding solid particles and large molecules.

Back  -    New Search

blood casts pl. n.

fragments of cellular material (see CAST) to which blood cells are attached, which are derived from the kidney tubules and are excreted in the urine in certain kidney diseases.

Back  -    New Search

blood cell (blood corpuscle) n.

any of the cells that are present in the blood in health or disease. The cells may be subclassified into three major categories: red cells (see ERYTHROCYTE), white cells (see LEUCOCYTE), and platelets. See illustration.

Back  -    New Search

blood clot n.

a solid mass formed as the result of blood coagulation, either within the blood vessels and heart or elsewhere. See also THROMBOSIS.

Back  -    New Search

blood clotting n.

see BLOOD COAGULATION.

Back  -    New Search

blood coagulation (blood clotting) n.

the process whereby blood is converted from a liquid to a solid state. The process involves the interaction of a variety of substances (see COAGULATION FACTORS) and leads to the production of the enzyme thrombin, which converts the soluble blood protein fibrinogen to the insoluble protein fibrin. Blood coagulation is an essential mechanism for the arrest of bleeding (haemostasis).

Back  -    New Search

blood corpuscle n.

see BLOOD CELL.

Back  -    New Search

blood count n.

the numbers of different blood cells in a known volume of blood, usually expressed as the number of cells per litre. See also DIFFERENTIAL LEUCOCYTE COUNT.

Back  -    New Search

blood donor n.

a person who gives blood for storage in a blood bank.

Back  -    New Search

blood group n.

any one of the many types into which a person's blood may be classified, based on the presence or absence of certain inherited antigens on the surface of the red blood cells. Blood of one group contains antibodies in the serum that react against the cells of other groups. One of the most important blood group systems is the ABO system . It is based on the presence or absence of antigens A and B: blood of groups A and B contains antigens A and B, respectively; group AB contains both antigens and group O neither. Blood of group A contains antibodies to antigen B; group B blood contains anti-A antibodies or isoagglutinins; group AB has neither antibody and group O has both. The table below illustrates which blood groups can be used in transfusion for each of the four groups. See also RHESUS FACTOR.

Donor's blood group

Blood group of people donor can receive blood from

Blood group of people donor can give blood to

A

A,O

A,AB

B

B,O

B,AB

AB

A,B,AB,O

AB

O

O

A,B,AB,O

Back  -    New Search

blood plasma n.

see PLASMA.

Back  -    New Search

blood poisoning n.

the presence of either bacterial toxins or large numbers of bacteria in the bloodstream causing serious illness. See PYAEMIA, SEPTICAEMIA, TOXAEMIA.

Back  -    New Search

blood pressure n.

the pressure of blood against the walls of the main arteries. Pressure is highest during systole, when the ventricles are contracting (systolic pressure ), and lowest during diastole, when the ventricles are relaxing and refilling (diastolic pressure ). Blood pressure is measured — in millimetres of mercury — by means of a sphygmomanometer at the brachial artery of the arm. A young adult would be expected to have a systolic pressure of around 120 mm and a diastolic pressure of 80 mm. These are recorded as 120/80. See also HYPERTENSION, HYPOTENSION.

Back  -    New Search

blood serum n.

see SERUM.

Back  -    New Search

blood sugar n.

the concentration of glucose in the blood, normally expressed in millimoles per litre. The normal range is 3.5–5.5 mmol/l. Blood-sugar estimation is an important investigation in a variety of diseases, most notably in diabetes mellitus. See also HYPERGLYCAEMIA, HYPOGLYCAEMIA.

Back  -    New Search

blood test n.

any test designed to discover abnormalities in a sample of a person's blood or to determine the blood group.

Back  -    New Search

blood transfusion n.

see TRANSFUSION.

Back  -    New Search

blood vessel n.

a tube carrying blood away from or towards the heart. See ARTERY, ARTERIOLE, VEIN, VENULE, CAPILLARY.

Back  -    New Search

blue baby (bloo) n.

an infant suffering from congenital heart disease in which the circulation is misdirected. This results in the presence of partially deoxygenated blood (which is blue in colour) in the peripheral circulation, which gives the skin and lips a characteristic purple colour (see CYANOSIS).

Back  -    New Search

B-lymphocyte n.

see LYMPHOCYTE.

Back  -    New Search

Boari flap (boh-ah-ri) n.

a tube of bladder tissue constructed to replace the lower third of the ureter when this has been destroyed or damaged or has to be removed because of the presence of a tumour. See also URETEROPLASTY. [A. Boari (19th century), Italian surgeon]

Back  -    New Search

body (bod-i) n.

1 an entire animal organism.

2 the trunk of an individual, excluding the limbs.
Top

3 the main or largest part of an organ.
Top

4 a solid discrete mass of tissue; e.g. the carotid body. See also CORPUS.
Top

Back  -    New Search

body image (body schema) n.

the individual's concept of the disposition of his limbs and the identity of the different parts of his body.

Back  -    New Search

body temperature n.

the intensity of heat of the body, as measured by a thermometer. In most normal individuals body temperature is maintained at about 37°C (98.4°F). A rise in body temperature occurs in fever.

Back  -    New Search

Boeck's disease (beeks) n.

see SARCOIDOSIS. [C. P. M. Boeck (1845–1913), Norwegian dermatologist]

Back  -    New Search

boil (boil) n.

a tender inflamed area of the skin containing pus. The infection is usually caused by the bacterium Staphylococcus aureus, which enters through a hair follicle or a break in the skin. Boils usually heal when the pus is released or with antibiotic treatment, though occasionally they may cause more widespread infection. Medical name: furuncle .

Back  -    New Search

bolus (boh-ls) n.

a soft mass of chewed food or a pharmaceutical preparation that is ready to be swallowed.

Back  -    New Search

bonding (bond-ing) n.

1 (in psychology) the development of a close and selective relationship, such as that of attachment.

2 (in dentistry) the attachment of dental restorations, sealants, and orthodontic brackets to teeth.
Top

Back  -    New Search

bone (bohn) n.

the hard extremely dense connective tissue that forms the skeleton of the body. It is composed of a matrix of collagen fibres impregnated with bone salts, chiefly calcium carbonate and calcium phosphate (hydroxyapatite), in which bone cells (osteocytes) are embedded. compact (or cortical ) b. the outer shell of bones, consisting of a hard virtually solid mass made up of bony tissue arranged in concentric layers (Haversian systems ). spongy (or cancellous ) b. bone found beneath the outer shell; it consists of a meshwork of bony bars (trabeculae ) with many interconnecting spaces containing marrow.

Back  -    New Search

bone graft

see GRAFT.

Back  -    New Search

bone marrow (marrow) n.

the tissue contained within the internal cavities of the bones. At birth, these cavities are filled entirely with blood-forming myeloid tissue (red marrow) but in later life the marrow in the limb bones is replaced by fat (yellow marrow ).

Back  -    New Search

Bonney's blue (bon-iz) n.

a dye consisting of a mixture of crystal violet and brilliant green. It is used as a skin disinfectant and to demonstrate the presence of a fistula, by instilling it via a cannula and tracing its path. [W. F. V. Bonney (1872–1953), British gynaecologist]

Back  -    New Search

bony labyrinth (boh-ni) n.

see LABYRINTH.

Back  -    New Search

BOO n.

bladder outflow obstruction, usually by an enlarged prostate gland.

Back  -    New Search

BOOP n.

bronchiolitis obliterans organizing pneumonia. See BRONCHIOLITIS.

Back  -    New Search

borax (bor-aks) n.

a mild astringent with a weak antiseptic action, applied externally to skin and mucous membranes. Borax and boric acid are used in mouth and nasal washes, gargles, eye lotions and contact-lens solutions, and in dusting powder.

Back  -    New Search

borborygmus (bor-ber-ig-ms) n. (pl. borborygmi)

an abdominal gurgle due to movement of fluid and gas in the intestine.

Back  -    New Search

borderline (bor-der-lyn) adj.

1 describing a personality disorder characterized by unstable and intense relationships, exploiting and manipulating other people, rapidly changing moods, recurrent suicidal or self-injuring acts, and a pervasive inner feeling of emptiness and boredom.see SCHIZOTYPAL.

Back  -    New Search

Bordetella (bor-d-tel-) n.

a genus of tiny Gram-negative aerobic bacteria. B. pertussis the cause of whooping cough.

Back  -    New Search

boric acid (bor-ik) n.

see BORAX.

Back  -    New Search

borneol (bor-nee-ol) n.

an essential oil used, in preparations with other essential oils, such as menthol, menthone, and camphene, to disperse gallstones and kidney stones. It is administered by mouth. Trade names: Rowachol , Rowatinex .

Back  -    New Search

Bornholm disease (devil's grip, epidemic myalgia, epidemic pleurodynia) (born-holm) n.

a disease caused by Coxsackie viruses. It is spread by contact; symptoms include fever, headache, and attacks of severe pain in the lower chest. The illness lasts about a week and is rarely fatal.

Back  -    New Search

bottom shuffling (bot-m shuf-ling) n.

a normal variant of crawling in which babies sit upwards and move on their bottoms, usually by pulling forward on their heels. Babies who bottom-shuffle tend to walk slightly later. There is often a family history of bottom shuffling.

Back  -    New Search

botulinum toxin (bot-yoo-ly-nm) n.

a powerful nerve toxin, produced by the bacterium Clostridium botulinum, that is used, in minute dosage, for the treatment of various conditions of muscle overaction, such as strabismus (squint) and blepharospasm, and achalasia. It is administered by injection. Trade name: Dysport .

Back  -    New Search

botulism (bot-yoo-lizm) n.

a serious form of food poisoning from foods containing the toxin produced by the bacterium Clostridium botulinum, which thrives in improperly preserved foods. The toxin selectively affects the central nervous system; some cases are fatal.

Back  -    New Search

Bouchard's node (boo-shahdz) n.

a bony thickening arising at the proximal interphalangeal joint of a finger in osteoarthritis. It is often found together with Heberden's nodes. [J. C. Bouchard (1837–1915), French physician]

Back  -    New Search

bougie (boo-zhee) n.

a hollow or solid cylindrical instrument, usually flexible, that is inserted into tubular passages, such as the oesophagus (gullet), rectum, or urethra. Bougies are used in diagnosis and treatment, particularly by enlarging strictures.

Back  -    New Search

Bourneville's disease (born--veez) n.

see TUBEROUS (SCLEROSIS). [D.-M. Bourneville (1840–1909), French neurologist]

Back  -    New Search

bowel (bow-l) n.

see INTESTINE.

Back  -    New Search

Bowen's disease (boh-nz) n.

a type of carcinoma of the squamous epidermal cells of the skin that does not spread to the basal layers. [J. T. Bowen (1857–1941), US dermatologist]

Back  -    New Search

bow-legs (boh-legz) pl. n.

abnormal out-curving of the legs, resulting in a gap between the knees on standing. Medical name: genu varum .

Back  -    New Search

Bowman's capsule (boh-mnz) n.

see GLOMERULUS. [Sir W. P. Bowman (1816–92), British physician]

Back  -    New Search

BPH n.

benign prostatic hypertrophy. See PROSTATE GLAND.

Back  -    New Search

brachi- (brachio-) prefix

denoting the arm.

Back  -    New Search

brachial (brayk-il) adj.

relating to or affecting the arm.

Back  -    New Search

brachial artery n.

an artery that extends from the axillary artery at the armpit, down the side and inner surface of the upper arm to the elbow, where it divides into the radial and ulnar arteries.

Back  -    New Search

brachial plexus n.

a network of nerves, arising from the spine at the base of the neck, from which arise the nerves supplying the arm, forearm and hand, and parts of the shoulder girdle. See also RADIAL (NERVE).

Back  -    New Search

brachiocephalic artery (bray-ki-oh-si-fal-ik) n.

see INNOMINATE ARTERY.

Back  -    New Search

brachium (brayk-im) n. (pl. brachia)

the arm, especially the part of the arm between the shoulder and the elbow.

Back  -    New Search

brachy- prefix

denoting shortness.

Back  -    New Search

brachycephaly (brak-i-sef-li) n.

shortness of the skull, with a cephalic index of about 80.
—brachycephalic adj.

Back  -    New Search

brachytherapy (brak-i-th'e-rpi) n.

radiotherapy administered by implanting radioactive wires or grains into or close to a tumour. This technique is used in the treatment of many accessible tumours (e.g. breast cancer).

Back  -    New Search

Bradford's frame (brad-ferdz) n.

a rectangular metal frame with canvas slings attached, used to support and immobilize a patient in a prone or supine position. [E. H. Bradford (1848–1926), US orthopaedic surgeon]

Back  -    New Search

brady- prefix

denoting slowness.

Back  -    New Search

bradycardia (brad-i-kar-di) n.

slowing of the heart rate to less than 50 beats per minute.

Back  -    New Search

bradykinin (brad-i-ky-nin) n.

a naturally occurring polypeptide consisting of nine amino acids; it is a very powerful vasodilator and causes contraction of smooth muscle.

Back  -    New Search

brain (brayn) n.

the enlarged and highly developed mass of nervous tissue that forms the upper end of the central nervous system. It is invested by three connective tissue membranes (see MENINGES) and floats in cerebrospinal fluid within the rigid casing formed by the bones of the skull. See illustration. See also FOREBRAIN, HINDBRAIN, MIDBRAIN. Anatomical name: encephalon .

Back  -    New Search

brain death n.

see DEATH.

Back  -    New Search

brainstem (brayn-stem) n.

the enlarged extension upwards within the skull of the spinal cord, consisting of the medulla oblongata, the pons, and the midbrain.

Back  -    New Search

branchial cyst (brank-il) n.

a cyst that arises at the site of one of the embryonic pharyngeal pouches due to a developmental anomaly.

Back  -    New Search

branchial pouch n.

see PHARYNGEAL POUCH.

Back  -    New Search

Brandt Andrews method (brant an-drooz) n.

a technique for expelling the placenta from the uterus. Upward pressure is applied to the uterus through the abdominal wall while holding the umbilical cord taut. When the uterus is elevated in this way, the placenta will be in the cervix or upper vagina and is then expelled by applying pressure below the base of the uterus. [T. Brandt (1819–95), Swedish obstetrician; H. R. Andrews (1872–1942), British gynaecologist]0192800728.Braun's-splint.1.tif

Back  -    New Search

Braun's splint (brawnz) n.

a metal splint with attachments for pulleys, used to support or apply traction to a fractured lower limb. [H. F. W. Braun (1862–1934), German surgeon]

Back  -    New Search

breakbone fever (brayk-bohn) n.

see DENGUE.

Back  -    New Search

breast (brest) n.

1 the mammary gland of a woman: one of two compound glands that produce milk. Each breast consists of glandular lobules – the milk-secreting areas – embedded in fatty tissue. The milk passes from the lobules into lactiferous ducts , each of which discharges through a separate orifice in the nipple. See also LACTATION. Anatomical name: mamma .

2 the front part of the chest (thorax).

Top

Back  -    New Search

breastbone (brest-bohn) n.

see STERNUM.

Back  -    New Search

breast cancer n.

a malignant tumour of the breast, usually a carcinoma, rarely a sarcoma. It is unusual in men but is the commonest form of cancer in women, in some cases involving both breasts.

Back  -    New Search

breast implant n.

see IMPLANT.

Back  -    New Search

breath-holding attacks (breth-hohld-ing) pl. n.

episodes in which a young child cries, holds its breath, and goes blue, which may result in loss of consciousness. The attacks cease spontaneously.

Back  -    New Search

breathing (breeth-ing) n.

the alternation of active inhalation of air into the lungs through the mouth or nose with the passive exhalation of the air. Breathing is part of respiration and is sometimes called external respiration .

Back  -    New Search

breathlessness (breth-lis-nis) n.

see DYSPNOEA.

Back  -    New Search

breath sounds (breth) pl. n.

the sounds heard through a stethoscope placed over the lungs during breathing. See BRONCHIAL BREATH SOUNDS, CAVERNOUS BREATH SOUNDS, VESICULAR BREATH SOUNDS.

Back  -    New Search

breech presentation (breech) n.

the position of a baby in the uterus such that it would be delivered buttocks first (instead of the normal head-first position).

Back  -    New Search

bregma (breg-m) n.

the point on the top of the skull at which the coronal and sagittal sutures meet. In a young infant this is an opening, the anterior fontanelle.

Back  -    New Search

Breslow's measurement (or thickness) (brez-lohz) n.

the distance (in millimetres) between the surface and the deepest extent of a malignant melanoma. The measurement correlates with prognosis; tumours that are less than 0.76 mm thick have a good prognosis. [A. Breslow (1928–80), US pathologist]

Back  -    New Search

bretylium tosylate (bre-til-im to-sy-layt) n.

a drug used in patients with cardiac arrest to reverse ventricular fibrillation that has failed to respond to electrical defibrillation. It is administered by intravenous injection. Trade name: Bretylate .

Back  -    New Search

Bright's disease (bryts) n.

see NEPHRITIS. [R. Bright (1789–1858), British physician]

Back  -    New Search

brilliant green (bril-ynt) n.

an aniline dye used as an antiseptic.

Back  -    New Search

Briquet's syndrome (bree-kayz) n.

see SOMATIZATION DISORDER. [P. Briquet (1796–1881), French psychiatrist]

Back  -    New Search

British Anti-Lewisite (BAL) (brit-ish anti-loo-i-syt) n.

see DIMERCAPROL.

Back  -    New Search

Broadbent's sign (brawd-bents) n.

retraction of the left side and back near the 11th and 12th ribs with every heartbeat, indicating adhesions between the pericardium and the diaphragm. [Sir W. H. Broadbent (1835–1907), British physician]

Back  -    New Search

broad ligaments (brawd) pl. n.

folds of peritoneum extending from each side of the uterus to the lateral walls of the pelvis, supporting the uterus and Fallopian tubes, and forming a partition across the pelvic cavity.

Back  -    New Search

Broca's area (broh-kz) n.

the area of cerebral motor cortex responsible for the initiation of speech. It is situated in the left frontal lobe in most (but not all) right-handed people. [P. P. Broca (1824–80), French surgeon]

Back  -    New Search

Brodie's abscess (broh-diz) n.

see ABSCESS. [Sir B. C. Brodie (1783–1862), British surgeon]

Back  -    New Search

bromazepam (broh-maz--pam) n.

a long-acting benzodiazepine drug used in the short-term treatment of disabling anxiety. It is administered by mouth. Trade name: Loxetan .

Back  -    New Search

bromism (broh-mizm) n.

a group of symptoms, including drowsiness, loss of sensation, and slurred speech, caused by excessive intake of bromides.

Back  -    New Search

bromocriptine (broh-moh-krip-teen) n.

a drug, derived from ergot, that is administered by mouth in the treatment of parkinsonism and acromegaly and to prevent lactation by inhibiting the secretion of the hormone prolactin by the pituitary gland. Trade name: Parlodel .

Back  -    New Search

Brompton cocktail (bromp-tn kok-tayl) n.

a mixture of alcohol, morphine, and cocaine sometimes given to control severe pain in terminally ill people, especially those dying of cancer. The mixture was first tried at the Brompton Hospital, London.

Back  -    New Search

bromsulphthalein (brom-sulf-th-lin) n.

a blue dye used in tests of liver function.

Back  -    New Search

bronch- (broncho-) prefix

denoting the bronchial tree.

Back  -    New Search

bronchial breath sounds (bronk-il) pl. n.

breath sounds transmitted through consolidated lungs in pneumonia; they are similar to the sounds heard normally over the larger bronchi and are louder and harsher than vesicular breath sounds.

Back  -    New Search

bronchial carcinoma n.

cancer of the bronchus, one the commonest causes of death in smokers. See also LUNG CANCER, OAT-CELL CARCINOMA.

Back  -    New Search

bronchial tree n.

a branching system of tubes conducting air from the trachea to the lungs: includes the bronchi and their subdivisions and the bronchioles.

Back  -    New Search

bronchiectasis (bronk-i-ek-t-sis) n.

widening of the bronchi or their branches. It may be congenital or it may result from infection or obstruction. Pus may form in the widened bronchus so that the patient coughs up purulent sputum, which may contain blood. Treatment consists of antibiotic drugs to control the infection and physiotherapy to drain the sputum. Surgery may be used if only a few segments of the bronchi are affected.

Back  -    New Search

bronchiole (bronk-i-ohl) n.

a subdivision of the bronchial tree that does not contain cartilage or mucous glands in its wall. The smallest bronchioles open into the alveoli.
—bronchiolar adj.

Back  -    New Search

bronchiolitis (bronk-i-oh-ly-tis) n.

inflammation of the small airways in the lungs (see BRONCHIOLE) due to infection by viruses, usually the respiratory syncytial virus. b. obliterans organizing pneumonia (BOOP) a flulike illness with cough, fever, and shortness of breath; there are patchy infiltrates on X-ray. It may result from a viral infection, be caused by certain drugs, or be associated with connective tissue disease.

Back  -    New Search

bronchitis (brong-ky-tis) n.

inflammation of the bronchi. acute b. bronchitis caused by viruses or bacteria. It is characterized by coughing, the production of mucopurulent sputum, and bronchospasm. chronic b. bronchitis in which the patient coughs up excessive mucus secreted by enlarged bronchial mucous glands; the bronchospasm cannot be relieved by bronchodilator drugs. The disease is particularly prevalent in Britain in association with cigarette smoking, air pollution, and emphysema.

Back  -    New Search

bronchoalveolar lavage (BAL) (brong-koh-al-vee-oh-ler) n.

a method of obtaining cellular material from the lungs that is used particularly in the investigation and monitoring of interstitial lung disease and in the investigation of pulmonary infiltrates in immunosuppressed patients.

Back  -    New Search

bronchoconstrictor (brong-koh-kn-strik-ter) n.

a drug that causes narrowing of the air passages by producing spasm of bronchial smooth muscle.

Back  -    New Search

bronchodilator (brong-koh-dy-lay-ter) n.

an agent, such as ephedrine or salbutamol, that causes widening of the air passages by relaxing bronchial smooth muscle.

Back  -    New Search

bronchography (brong-kog-rfi) n.

X-ray examination of the bronchial tree after it has been made visible by the injection of radiopaque dye or contrast medium. It has been largely superseded by CT scanning.

Back  -    New Search

bronchomycosis (brong-koh-my-koh-sis) n.

any of various fungal infections of the bronchi, such as candidosis of the lungs.

Back  -    New Search

bronchophony (brong-kof-ni) n.

see VOCAL RESONANCE.

Back  -    New Search

bronchopleural (brong-koh-ploor-l) adj.

relating to a bronchus and the pleura. b. fistula an abnormal communication (see FISTULA) between a bronchus and the pleural cavity.

Back  -    New Search

bronchopneumonia (brong-koh-new-moh-ni) n.

see PNEUMONIA.

Back  -    New Search

bronchopulmonary (brong-koh-pul-mn-er-i) adj.

relating to the lungs and the bronchial tree. b. dysplasia a chronic lung disease of newborn babies usually caused by trauma resulting from artificial ventilation of the lungs with oxygen under pressure.

Back  -    New Search

bronchoscope (bronk--skohp) n.

an instrument used to look into the trachea and bronchi. With the aid of a bronchoscope the bronchial tree can be washed out (see BRONCHOALVEOLAR LAVAGE) and samples of tissue and foreign bodies can be removed with long forceps.
—bronchoscopy (brong-kos-k-pi) n.

Back  -    New Search

bronchospasm (brong-koh-spazm) n.

narrowing of bronchi by muscular contraction in response to some stimulus, as in asthma and bronchitis. Some types of bronchospasm can usually be relieved by bronchodilator drugs; others, such as chronic bronchitis, usually cannot.

Back  -    New Search

bronchus (bronk-s) n. (pl. bronchi)

any of the air passages beyond the trachea that has cartilage and mucous glands in its wall. See also BRONCHIOLE
—bronchial adj.

Back  -    New Search

brown fat (brown) n.

a form of fat in adipose tissue that is a rich source of energy and can be converted rapidly to heat. There is speculation that a rapid turnover of brown fat occurs to balance excessive intake of food and unnecessary production of white fat (making up the bulk of adipose tissue). Some forms of obesity may be linked to lack of – or inability to synthesize – brown fat.

Back  -    New Search

Brown-Séquard syndrome (brown say-kar) n.

the neurological condition resulting when the spinal cord has been partly cut through. Below the lesion there is a spastic paralysis on the same side and a loss of pain and temperature sensation on the opposite side. [C. E. Brown-Séquard (1818–94), French physiologist]

Back  -    New Search

Brucella (broo-sel-) n.

a genus of Gram-negative aerobic spherical or rodlike parasitic bacteria responsible for brucellosis (undulant fever) in humans and contagious abortion in cattle, pigs, sheep, and goats. The principal species are B. abortus and B. melitensis.

Back  -    New Search

brucellosis (Malta fever, Mediterranean fever, undulant fever) (broo-si-loh-sis) n.

a chronic disease of farm animals caused by bacteria of the genus Brucella, which can be transmitted to humans either by contact with an infected animal or by drinking nonpasteurized contaminated milk. Symptoms include headache, fever, aches and pains, and sickness; occasionally a chronic form develops with recurrent symptoms.

Back  -    New Search

Bruch's membrane (bruuks) n.

the transparent innermost layer of the choroid, which is in contact with the retinal pigment epithelium (see RETINA). [K. W. L. Bruch (1819–84), German anatomist]

Back  -    New Search

Brufen (broo-fn) n.

see IBUPROFEN.

Back  -    New Search

bruise (contusion) (brooz) n.

an area of skin discoloration caused by the escape of blood from ruptured underlying vessels following injury.

Back  -    New Search

bruit (broot) n.

see MURMUR.

Back  -    New Search

Brunner's glands (brun-erz) pl. n.

compound glands of the small intestine, found in the duodenum and the upper part of the jejunum. They are embedded in the submucosa and secrete mucus. [J. C. Brunner (1653–1727), Swiss anatomist]

Back  -    New Search

Brushfield spots (brush-feeld) pl. n.

greyish-brown spots seen in the iris of the eye. They can be found in normal individuals but are usually associated with Down's syndrome. [T. Brushfield (1858–1937), British physician]

Back  -    New Search

BSE n.

bovine spongiform encephalopathy. See CREUTZFELDT-JAKOB DISEASE, SPONGIFORM ENCEPHALOPATHY.

Back  -    New Search

BSS n.

see BALANCED SALT SOLUTION.

Back  -    New Search

bubo (bew-boh) n.

a swollen inflamed lymph node in the armpit or groin, commonly developing in soft sexually transmitted diseases (e.g. soft sore), bubonic plague, and leishmaniasis.

Back  -    New Search

bubonic plague (bew-bon-ik) n.

see PLAGUE.

Back  -    New Search

buccal (buk-l) adj.

relating to the mouth or the hollow part of the cheek.

Back  -    New Search

buccinator (buks-i-nay-ter) n.

a muscle of the cheek that has its origin in the maxilla and mandible. It is responsible for compressing the cheek and is important in mastication.

Back  -    New Search

Budd-Chiari syndrome (bud-ki-ah-ri) n.

a rare condition that follows obstruction of the hepatic vein by a blood clot or tumour. It is characterized by ascites and cirrhosis of the liver. [G. Budd (1808–82), British physician; H. Chiari (1851–1916), German pathologist]

Back  -    New Search

budesonide (bew-dess--nyd) n.

a corticosteroid drug used in a nasal spray to treat hay fever or as an inhalant for asthma. It is also administered as a cream or ointment for the treatment of eczema, psoriasis, and similar conditions. Trade names: Pulmicort , Preferid .

Back  -    New Search

Buerger's disease (ber-gerz) n.

an inflammatory condition affecting the arteries, especially the arteries of the legs. The condition may lead to gangrene of the limbs and venous or coronary thrombosis. Medical name: thromboangiitis obliterans . [L. Buerger (1879–1943), US physician]

Back  -    New Search

bufexamac (bew-feks--mak) n.

an anti-inflammatory drug (see NSAID) administered externally in the form of a cream for the treatment of skin inflammation and to relieve itching.

Back  -    New Search

buffer (buf-er) n.

a solution whose hydrogen ion concentration (pH) remains virtually unchanged by dilution or by the addition of acid or alkali. See also ACID-BASE BALANCE.

Back  -    New Search

bulb (bulb) n.

(in anatomy) any rounded structure or a rounded expansion at the end of an organ or part.

Back  -    New Search

bulbar (bul-ber) adj.

1 relating to or affecting the medulla oblongata.

2 relating to a bulb.
Top

3 relating to the eyeball.
Top

Back  -    New Search

bulbourethral glands (bul-bo-yoor-ee-thrl) n.

see COWPER'S GLANDS.

Back  -    New Search

bulimia (bew-lim-i) n.

insatiable overeating. This symptom may be psychogenic, as in anorexia nervosa (b. nervosa or the binge-purge syndrome ); or it may be due to neurological causes, such as a lesion of the hypothalamus.

Back  -    New Search

bulla (buul-) n. (pl. bullae)

1 a large blister, containing serous fluid.

2 (in anatomy) a rounded bony prominence.
Top

3 a thin-walled air-filled space within the lung, arising congenitally or in emphysema.
Top

—bullous adj.

Back  -    New Search

Buller's shield (buul-erz) n.

a protective shield placed over one eye when the other is infected. It consists of a watch glass fixed in position with adhesive tape. [F. Buller (1844–1905), Canadian ophthalmologist]

Back  -    New Search

bullous pemphigoid (buul-s) n.

see PEMPHIGOID.

Back  -    New Search

bumetanide (bew-met--nyd) n.

a quick-acting diuretic used to relieve the fluid retention (oedema) occurring in heart failure, kidney disease, and cirrhosis of the liver. It is administered by mouth or by injection. Trade name: Burinex .

Back  -    New Search

bundle (bun-d'l) n.

a group of muscles or nerve fibres situated close together and running in the same direction.

Back  -    New Search

bundle branch block n.

a defect in the specialized conducting tissue of the heart that is recognized as an electrocardio-graphic abnormality.

Back  -    New Search

bundle of His (hiss) n.

see ATRIOVENTRICULAR BUNDLE. [W. His (1863–1934), Swiss anatomist]

Back  -    New Search

bunion (bun-yn) n.

a swelling of the joint between the great toe and the first metatarsal bone. A bursa often develops over the site and the great toe becomes displaced towards the others. Bunions are usually caused by ill-fitting shoes and may require surgical treatment.

Back  -    New Search

buphthalmos (hydrophthalmos) (buf-thal-ms) n.

infantile or congenital glaucoma: increased pressure within the eye due to a defect in the development of the tissues through which fluid drains from the eye.

Back  -    New Search

bupivacaine (bew-piv--kayn) n.

a potent local anaesthetic, used mainly for regional nerve block. Trade name: Marcain .

Back  -    New Search

buprenorphine (bew-pren-or-feen) n.

a powerful synthetic opiate painkilling drug; it acts for 6–8 hours and is administered by mouth. Trade name: Temgesic .

Back  -    New Search

bur (ber) n.

1 a cutting drill that fits in a dentist's handpiece. Burs are mainly used for cutting cavities in teeth.

2 (or burr) a surgical drill for cutting through bone. b. hole a circular hole drilled through the skull to release pressure inside the skull or to facilitate biopsies and other procedures.
Top

Back  -    New Search

Burkitt's lymphoma (Burkitt's tumour) (ber-kits) n.

a malignant tumour of the lymphatic system, most commonly affecting children and largely confined to tropical Africa. It is the most rapidly growing malignancy, with a tumour doubling time of about five days. It can arise at various sites, most commonly the facial structures, such as the jaw, and in the abdomen. [D. P. Burkitt (1911–93), Irish surgeon]

Back  -    New Search

burn (bern) n.

tissue damage caused by such agents as heat, chemicals, electricity, sunlight, or nuclear radiation. Burns cause swelling and blistering; loss of plasma from damaged blood vessels may lead to severe shock. There is also a risk of bacterial infection. first-degree b. a burn affecting only the outer layer (epidermis) of the skin. second-degree b. a burn in which both the epidermis and the underlying dermis are damaged. third-degree b. a burn that involves damage or destruction of the skin to its full depth and damage to the tissues beneath.

Back  -    New Search

burr (ber) n.

see BUR.

Back  -    New Search

bursa (ber-s) n. (pl. bursae)

a small sac of fibrous tissue that is lined with synovial membrane and filled with fluid. Bursae help to reduce friction; they are normally formed round joints and in places where ligaments and tendons pass over bones.

Back  -    New Search

bursa of Fabricius (f-brish-s) n.

a mass of lymphoid tissue occurring as an outgrowth of the cloaca of young birds. It is an important source of B-lymphocytes. [H. Fabricius (1537–1619), Italian anatomist]

Back  -    New Search

bursitis (ber-sy-tis) n.

inflammation of a bursa, resulting from injury, infection, or rheumatoid synovitis. It produces pain and sometimes restricts movement at a nearby joint. See also HOUSEMAID'S KNEE.

Back  -    New Search

buserelin (bew-s-rel-in) n.

a drug (see LHRH ANALOGUE) that is administered as a nasal spray for the treatment of endometriosis and to help in the management of advanced cancer of the prostate gland. Trade names: Suprecur , Suprefact .

Back  -    New Search

buspirone (bew-spy-rohn) n.

a tranquillizer used to relieve the symptoms of anxiety. Trade name: Buspar .

Back  -    New Search

busulphan (bew-sul-fan) n.

a drug that destroys cancer cells by acting on the bone marrow. It is administered by mouth, mainly in the treatment of chronic myeloid leukaemia. Trade name: Myleran .

Back  -    New Search

butobarbitone (butobarbital) (bew-toh-bar-bi-tohn) n.

an intermediate-acting barbiturate, used for the treatment of insomnia and for sedation. Trade name: Soneryl .

Back  -    New Search

butriptyline (bew-trip-ti-leen) n.

a tricyclic antidepressant drug administered by mouth.

Back  -    New Search

buttock (but-k) n.

either of the two fleshy protuberances at the lower posterior section of the trunk, consisting of muscles (see GLUTEUS) and fat. Anatomical name: natis .

Back  -    New Search

butyrophenone (bew-ti-roh-fee-nohn) n.

one of a group of chemically related antipsychotic drugs that includes haloperidol, droperidol, benperidol, and trifluperidol.

Back  -    New Search

bypass (by-pahs) n.

diversion of a flow from its normal channels, usually by means of surgery. See ANASTOMOSIS, CARDIOPULMONARY BYPASS, CORONARY BYPASS GRAFT, SHUNT.

Back  -    New Search

byssinosis (bis-i-noh-sis) n.

an industrial disease of the lungs caused by inhalation of dusts of cotton, flax, hemp, or sisal.

Back  -    New Search

C

C

1 symbol for carbon.

2 abbreviation for Celsius or centigrade.
Top

Back  -    New Search

Ca

symbol for calcium.

Back  -    New Search

CABG n.

coronary artery bypass graft. See CORONARY BYPASS GRAFT.

Back  -    New Search

cac- (caco-) prefix

denoting disease or deformity.

Back  -    New Search

cachet (kash-ay) n.

a flat capsule containing a drug that has an unpleasant taste. The cachet is swallowed intact by the patient.

Back  -    New Search

cachexia (k-keks-i) n.

a condition of abnormally low weight, weakness, and general bodily decline associated with chronic disease, such as cancer.

Back  -    New Search

cadaver (k-dav-er) n.

a dead body, especially one preserved and used for dissection and anatomical study.

Back  -    New Search

caecosigmoidostomy (see-koh-sig-moid-ost-mi) n.

an operation in which the caecum is joined to the sigmoid colon.

Back  -    New Search

caecostomy (see-kost-mi) n.

an operation in which the caecum is brought through the abdominal wall and opened in order to drain or decompress the intestine.

Back  -    New Search

caecum (see-km) n.

a blind-ended pouch at the junction of the small and large intestines, to which the vermiform appendix is attached.
—caecal adj.

Back  -    New Search

Caesarean section (siz-air-in) n.

a surgical operation for delivering a baby through the abdominal wall, usually by a transverse incision in the lower segment of the uterus (lower uterine segment C. s. ). It is carried out when there are risks to the baby or to the mother from normal childbirth and may be performed, if necessary, as soon as the child is viable.

Back  -    New Search

caesium-137 (seez-im) n.

an artificial radioactive isotope of the metallic element caesium, used in radiotherapy. Symbol: 137Cs. See also TELECURIETHERAPY.

Back  -    New Search

café au lait spots (kaf-ay-oh-lay) pl. n.

well-defined pale-brown patches on the skin. The presence of six or more in an individual is strongly suggestive of neurofibromatosis.

Back  -    New Search

caffeine (kaf-een) n.

an alkaloid drug, present in coffee and tea, that has a stimulant action on the central nervous system and is a weak diuretic. It is used in analgesic preparations.

Back  -    New Search

Caffey's disease (kaf-iz) n.

see HYPEROSTOSIS. [J. Caffey (1895–1966), US paediatrician]

Back  -    New Search

caisson disease (kay-sn) n.

see COMPRESSED AIR ILLNESS.

Back  -    New Search

calamine (kal--myn) n.

a preparation of zinc carbonate used as a mild astringent on the skin in the form of a lotion, cream, or ointment.

Back  -    New Search

calc- (calci-, calco-) prefix

denoting calcium or calcium salts.

Back  -    New Search

calcaneus (heel bone) (kal-kay-nis) n.

the large bone in the tarsus of the foot that forms the projection of the heel behind the foot.

Back  -    New Search

calcareous (kal-kair-is) adj.

containing calcium, especially calcium carbonate; chalky.

Back  -    New Search

calciferol (kal-sif-er-ol) n.

see VITAMIN D.

Back  -    New Search

calcification (kal-si-fi-kay-shn) n.

the deposition of calcium salts in tissue. This occurs as part of the normal process of bone formation (see OSSIFICATION).

Back  -    New Search

calcinosis (kal-si-noh-sis) n.

the abnormal deposition of calcium salts in the tissues.

Back  -    New Search

calcipotriol (kal-si-pot-ri-ol) n.

a vitamin D analogue administered as an ointment for the treatment of psoriasis. Trade name: Dovonex .

Back  -    New Search

calcitonin (thyrocalcitonin) (kal-si-toh-nin) n.

a hormone, produced by the C cells of the thyroid gland, that lowers the levels of calcium and phosphate in the blood. Calcitonin is given by injection to treat hypercalcaemia and Paget's disease of bones. Compare PARATHYROID HORMONE.

Back  -    New Search

calcium (kal-sim) n.

a metallic element that is an important constituent of bones, teeth, and blood. It is also essential for many metabolic processes, including nerve function, muscle contraction, and blood clotting. Symbol: Ca.

Back  -    New Search

calcium antagonist n.

a drug that inhibits the influx of calcium ions into cardiac and smooth-muscle cells; it therefore reduces the strength of heart-muscle contraction, reduces conduction of impulses in the heart, and causes vasodilatation. Calcium antagonists include amlodipine, diltiazem, nicardepine, nifedipine, and verapamil, which are used to treat angina and high blood pressure.

Back  -    New Search

calcium carbonate (kar-b-nayt) n.

a salt of calcium that neutralizes acids and is used in many antacid preparations. Formula:
CaCO_3
.

Back  -    New Search

calcium gluconate and calcium lactate (gloo-k-nayt, lak-tayt) n.

salts of calcium that are used to treat and prevent disorders caused by calcium deficiency, such as tetany and rickets. Formulae:
(CH_2OH(CHOH)4COO)2Ca.H_2O; (CH_3CHOHCOO)2Ca.5H_2O
.

Back  -    New Search

calculosis (kal-kew-loh-sis) n.

the presence of multiple calculi in the body.

Back  -    New Search

calculus (kal-kew-ls) n. (pl. calculi)

1 a stone: a hard pebble-like mass formed within the body, particularly in the gall bladder (see GALLSTONE) or anywhere in the urinary tract. Calculi may also occur in the ducts of the salivary glands.

2 a calcified deposit that forms on the surfaces of teeth.
Top

Back  -    New Search

Caldwell-Luc operation (kawld-wel look) n.

an operation in which the maxillary sinus is drained through an incision above the upper canine tooth. [G. W. Caldwell (1834–1918), US otolaryngologist; H. Luc (1855–1925), French laryngologist]

Back  -    New Search

calibrator (kal-i-bray-ter) n.

1 an instrument used for measuring the size of a tube or opening
.
2 an instrument used for dilating a tubular part, such as the gullet.
Top

Back  -    New Search

caliectasis (hydrocalycosis) (kal-i-ek-t-sis) n.

dilatation or distension of the calyces of the kidney, mainly associated with hydronephrosis and usually demonstrated by ultrasound or IVP (see INTRAVENOUS PYELOGRAM).

Back  -    New Search

calliper (caliper) (kal-i-per) n.

1 an instrument with two prongs or jaws, used for measuring diameters, particularly of the pelvis in obstetrics.

2 (also called calliper splint) a surgical appliance (see ORTHOSIS) that is used to correct or control deformity of a joint in the leg. It consists of a metal bar that is fixed to the shoe and held to the leg by means of straps.
Top

Back  -    New Search

callosity (callus) (k-los-iti) n.

a hard thick area of skin occurring in parts of the body subject to pressure or friction, particularly the soles of the feet and palms of the hands.

Back  -    New Search

callus (kal-s) n.

1 the tissue that forms between bone ends when a fracture is healing. It initially consists of blood clot and granulation tissue, which develops into cartilage and eventually new bone, which unites the fracture.

2 see CALLOSITY.
Top

Back  -    New Search

calor (kal-er) n.

heat: one of the four classical signs of inflammation in a tissue. See also DOLOR, RUBOR, TUMOR.

Back  -    New Search

calorie (kal-er-i) n.

a unit of heat equal to the amount of heat required to raise the temperature of 1 gram of water from 14.5°C to 15.5°C (the 15° calorie). One Calorie (kilocalorie or kilogram calorie ) is equal to 1000 calories; this unit is used to indicate the energy value of foods. Both these units have now largely been replaced by the joule and kilojoule respectively (1 calorie = 4.1855 joules).

Back  -    New Search

calorific (kal-er-if-ik) adj.

producing heat.

Back  -    New Search

calorimeter (kal-er-im-it-er) n.

any apparatus used to measure the heat lost or gained during various chemical and physical changes. Calorimeters are used to determine the energy value of different foods.
—calorimetry n.

Back  -    New Search

calvaria (kal-vair-i) n.

the vault of the skull.

Back  -    New Search

calyx (kay-liks) n. (pl. calyces)

a cup-shaped part, especially any of the divisions of the pelvis of the kidney.

Back  -    New Search

camphor (kam-fer) n.

a crystalline substance obtained from the tree Cinnamomum camphora that has been used to treat flatulence. Camphorated oil (camphor in cottonseed oil) is used in liniments as a counterirritant.

Back  -    New Search

Campylobacter (kam-pi-loh-bak-ter) n.

a genus of spiral motile Gram-negative bacteria that are a common cause of food poisoning, producing headache, nausea, diarrhoea, and vomiting. C. pylori see HELICOBACTER.

Back  -    New Search

canal (k-nal) n.

a tubular channel or passage; e.g. the alimentary canal.

Back  -    New Search

canaliculitis (ka-n-lik-yoo-ly-tis) n.

inflammation of a canaliculus, especially a lacrimal canaliculus (see LACRIMAL APPARATUS).

Back  -    New Search

canaliculus (ka-n-lik-yoo-ls) n. (pl. canaliculi)

a small channel or canal. Canaliculi occur, for example, in compact bone, linking lacunae containing bone cells; in the liver, transporting bile to the bile duct; and as part of the lacrimal apparatus of the eye.

Back  -    New Search

cancellous (kan-si-ls) adj.

lattice-like. c. bone spongy bone, which in a mature bone has a low density and is surrounded by denser cortical bone.

Back  -    New Search

cancer (kan-ser) n.

any malignant tumour, including carcinoma and sarcoma. It arises from the abnormal and uncontrolled division of cells that then invade and destroy the surrounding tissues. The cancer cells spread (see METASTASIS), setting up secondary tumours at sites distant from the original tumour.
There are probably many causative factors, some of which are known; for example, cigarette smoking is associated with lung cancer, radiation with some bone sarcomas and leukaemia, and several viruses are associated with various forms of cancer; genetic factors are implicated in the development of many cancers. Treatment of cancer depends on the type of tumour, the site of the primary tumour, and the extent of spread.

Back  -    New Search

cancer phobia n.

a personality disorder in which minor symptoms are interpreted as signs of cancer and panic attacks may occur. It leads to compulsively performed rituals, especially repeated hand-washing.

Back  -    New Search

cancrum oris (kank-rm or-iss) n.

ulceration of the lips and mouth. See also NOMA.

Back  -    New Search

Candida (kan-di-d) n.

a genus of yeasts (formerly called Monilia) that inhabit the vagina and alimentary tract. C. albicans a small oval budding species primarily responsible for candidosis.
—candidal adj.

Back  -    New Search

candidosis (candidiasis) (kan-di-doh-sis) n.

a common yeast infection of moist areas of the body, usually caused by Candida albicans. It is common in the vagina, where it is known as thrush , but is also found in the mouth and skin folds. On the skin the lesions are bright red with small satellite pustules, while in the mouth candidosis appears as white patches on the tongue or inside the cheeks. In the vagina it produces itching and sometimes a thick white discharge. Topical, intravaginal, or oral therapy with imidazoles is effective; nystatin, administered by mouth, helps to reduce candidal infection of the bowel.

Back  -    New Search

canine (kay-nyn) n.

the third tooth from the midline of each jaw. There are thus four canines, two in each jaw. It is known colloquially as the eye tooth .

Back  -    New Search

cannabis (kan--bis) n.

a drug prepared from the Indian hemp plant (Cannabis sativa), also known as pot , marijuana , hashish , and bhang . It produces euphoria and hallucinations and has little therapeutic value; its nonmedical use is illegal. See also DEPENDENCE.

Back  -    New Search

cannula (kan-yoo-l) n.

a hollow tube designed for insertion into a body cavity. The tube contains a sharp pointed solid core (trocar ), which facilitates its insertion and is withdrawn when the cannula is in place.

Back  -    New Search

cantharidin (kan-tha-ri-din) n.

the active principle of cantharides (see SPANISH FLY). A toxic and irritant chemical, cantharidin causes blistering of the skin and was formerly used in veterinary medicine as a counterirritant and vesicant.

Back  -    New Search

cantholysis (kan-thol-i-sis) n.

a surgical procedure to divide the attachment of the canthus (corner of the eye) from its underlying bone and tendon. It is performed as part of some operations on the eyelid.

Back  -    New Search

canthoplasty (kan-thoh-plasti) n.

a surgical procedure to reconstruct the canthus (corner of the eye).

Back  -    New Search

canthus (kan-ths) n.

either corner of the eye; the angle at which the upper and lower eyelids meet.
—canthal adj.

Back  -    New Search

cap (kap) n.

a covering or a cover-like part.

Back  -    New Search

CAPD n.

chronic ambulatory peritoneal dialysis: a method of treating renal failure on an out-patient basis. See HAEMODIALYSIS.

Back  -    New Search

capillary (k-pil-er-i) n.

an extremely narrow blood vessel. Capillaries form networks in most tissues; they are supplied with blood by arterioles and drained by venules. The vessel wall is only one cell thick, which enables exchange of oxygen, carbon dioxide, water, salts, etc., between the blood and the tissues.

Back  -    New Search

capitate (kap-i-tayt) adj.

head-shaped; having a rounded extremity. c. bone the largest bone of the wrist (see CARPUS). It articulates with the scaphoid and lunate bones behind, with the second, third, and fourth metacarpal bones in front, and with the trapezoid and hamate laterally.

Back  -    New Search

capitellum (kap-i-tel-m) n.

see CAPITULUM.

Back  -    New Search

capitulum (k-pit-yoo-lm) n.

the small rounded end of a bone that articulates with another bone. c. humeri (or capitellum ) the round prominence at the elbow end of the humerus that articulates with the radius.

Back  -    New Search

capreomycin (kap-ri-oh-my-sin) n.

an antibiotic drug, derived from the bacterium Streptomyces capreolus, that is administered by intramuscular injection in the treatment of tuberculosis. Trade name: Capastat .

Back  -    New Search

capsule (kaps-yool) n.

1 a membrane, sheath, or other structure that encloses a tissue or organ. joint c. the fibrous tissue, including the synovial membrane, that surrounds a freely movable joint.

2 a soluble case, usually made of gelatin, in which certain drugs are administered.
Top

3 the slimy substance that forms a protective layer around certain bacteria.
Top

Back  -    New Search

capsulitis (kaps-yoo-ly-tis) n.

inflammation of a joint capsule.

Back  -    New Search

capsulorrhexis (kaps-yoo-loh-rek-sis) n.

a surgical procedure in which a continuous circular tear is made in the lens capsule of the eye. anterior c. a tear made in the anterior surface of the lens capsule during cataract surgery, which makes the residual capsule much more resilient to being torn during surgery.

Back  -    New Search

capsulotomy (kaps-yoo-lot-mi) n.

an incision into the capsule of the lens, made after modern operations for cataract in which the capsule is not removed.

Back  -    New Search

captopril (kap-t-pril) n.

a drug used in the treatment of heart failure and hypertension; it acts by inhibiting the action of angiotensin (see ACE INHIBITOR). Trade names: Acepril , Capoten .

Back  -    New Search

caput succedaneum (kap-t suk-si-day-nim) n.

a temporary swelling of the soft parts of the head of a newly born infant that occurs during birth, due to compression by the muscles of the cervix (neck) of the uterus.

Back  -    New Search

carbachol (kar-b-kol) n.

a parasympathomimetic drug used after surgical operations to restore the function of inactive bowels or bladder. It is also (but now infrequently) used as a treatment for glaucoma.

Back  -    New Search

carbamazepine (kar-b-maz--peen) n.

an anticonvulsant drug used in the treatment of epilepsy and to relieve the pain of trigeminal neuralgia. Trade name: Tegretol .

Back  -    New Search

carbaryl (kar-b-ril) n.

a drug administered in the form of a lotion or shampoo to kill head and pubic lice. Trade names: Carylderm , Clinicide .

Back  -    New Search

carbenicillin (kar-ben-i-sil-in) n.

a synthetic penicillin. Administered by intramuscular injection, carbenicillin is effective against a wide range of bacterial infections. Trade name: Pyopen .

Back  -    New Search

carbenoxolone (kar-b-noks--lohn) n.

a drug that reduces inflammation, administered by mouth in the treatment of gastric ulcers or ulcers of the mouth. Trade names: Biogastrone , Bioral .

Back  -    New Search

carbimazole (kar-bim--zohl) n.

a drug used to reduce the production of thyroid hormone in cases of overactivity of the gland (thyrotoxicosis). Trade name: Neo-Mercazole .

Back  -    New Search

carbohydrate (kar-boh-hy-drayt) n.

any one of a large group of compounds, including the sugars and starch, that contain carbon, hydrogen, and oxygen and have the general formula
Cx(H_2O)y
. Carbohydrates are important as a source of energy: they are manufactured by plants and obtained by animals and man from the diet, being one of the three main constituents of food. See also DISAC-CHARIDE, MONOSACCHARIDE, POLYSACCHARIDE.

Back  -    New Search

carbol fuchsin (kar-bol fuuk-sin) n.

a red stain for bacteria and fungi, consisting of carbolic acid and fuchsin dissolved in alcohol and water.

Back  -    New Search

carbolic acid (kar-bol-ik) n.

see PHENOL.

Back  -    New Search

carbon dioxide (kar-bn dy-ok-syd) n.

a colourless gas formed in the tissues during metabolism and carried in the blood to the lungs, where it is exhaled (an increase in the concentration of this gas in the blood stimulates respiration). It forms a solid (dry ice) at -75°C (at atmospheric pressure) and in this form is used as a refrigerant. Formula:
CO_2
.

Back  -    New Search

carbonic anhydrase (kar-bon-ik an-hy-drayz) n.

an enzyme that catalyses the breakdown of carbonic acid into carbon dioxide and water or the combination of carbon dioxide and water to form carbonic acid. It therefore facilitates the transport of carbon dioxide from the tissues to the lungs.

Back  -    New Search

carbon monoxide (mn-ok-syd) n.

a colourless almost odourless gas that is very poisonous. When breathed in it combines with haemoglobin in the red blood cells (see CARBOXYHAEMOGLOBIN). Carbon monoxide is present in coal gas and motor exhaust fumes. Formula:
CO
.

Back  -    New Search

carbon tetrachloride (tet-r-klor-ryd) n.

a pungent volatile fluid used as a dry-cleaner. When inhaled or swallowed it may severely damage the heart, liver, and kidneys. Treatment is by administration of oxygen. Formula:
CCl_4
.

Back  -    New Search

carboplatin (kar-boh-plat-in) n.

a derivative of platinum that is used in the treatment of certain types of cancer. It is similar to cisplatin but has fewer side-effects.

Back  -    New Search

carboxyhaemoglobin (kar-boks-i-heem--gloh-bin) n.

a substance formed when carbon monoxide combines with the pigment haemoglobin in the blood. Carboxyhaemoglobin is incapable of transporting oxygen to the tissues and this is the cause of death in carbon monoxide poisoning.

Back  -    New Search

carboxyhaemoglobinaemia (kar-boks-i-heem--gloh-bi-nee-mi) n.

the presence of carboxyhaemoglobin in the blood.

Back  -    New Search

carbuncle (kar-bung-kl) n.

a collection of boils with multiple drainage channels. The infection is usually caused by Staphylococcus aureus and may result in an extensive slough of skin.

Back  -    New Search

carcin- (carcino-) prefix

denoting cancer or carcinoma.

Back  -    New Search

carcinogen (kar-sin--jin) n.

any substance that, when exposed to living tissue, may cause the production of cancer.
—carcinogenic (kar-sin--jen-ik) adj.

Back  -    New Search

carcinogenesis (kar-sin-oh-jen--sis) n.

the evolution of an invasive cancer cell from a normal cell. Intermediate stages, sometimes called premalignant , preinvasive , or noninvasive , may be recognizable.

Back  -    New Search

carcinoid (kar-sin-oid) n.

see ARGENTAFFINOMA.

Back  -    New Search

carcinoma (kar-sin-oh-m) n.

cancer that arises in epithelium, the tissue that lines the skin and internal organs of the body. It may occur in any tissue containing epithelial cells. Organs may exhibit more than one type of carcinoma; for example, an adenocarcinoma and a squamous carcinoma may be found in the cervix (but not usually concurrently).
—carcinomatous adj.

Back  -    New Search

carcinoma in situ (CIS) n.

the earliest stage of cancer spread, in which the tumour is confined to the epithelium and surgical removal of the growth should lead to cure. See also CERVICAL CANCER, CERVICAL INTRAEPITHELIAL NEOPLASIA.

Back  -    New Search

carcinomatosis (kar-sin-oh-m-toh-sis) n.

carcinoma that has spread widely throughout the body.

Back  -    New Search

carcinosarcoma (kar-sin-oh-sar-koh-m) n.

a malignant tumour of the cervix, uterus, or vagina containing a mixture of adenocarcinoma, sarcoma cells, and stroma. It may be bulky and polypoid, with grapelike fronds (sarcoma botryoides ).

Back  -    New Search

cardi- (cardio-) prefix

denoting the heart.

Back  -    New Search

cardia (kar-di) n.

1 the opening at the upper end of the stomach that connects with the oesophagus (gullet).

2 the heart.
Top

Back  -    New Search

cardiac (kar-di-ak) adj.

1 of, relating to, or affecting the heart.

2 of or relating to the upper part of the stomach (see CARDIA).
Top

Back  -    New Search

cardiac arrest n.

the cessation of effective pumping action of the heart, which most commonly occurs when the muscle fibres of the ventricles start to beat rapidly without pumping any blood (ventricular fibrillation) or when the heart stops beating completely (asystole). There is abrupt loss of consciousness, absence of the pulse, and breathing stops. Unless it is treated promptly, irreversible brain damage and death follow within minutes. Some patients may be resuscitated by massage of the heart, artificial respiration, and defibrillation.

Back  -    New Search

cardiac cycle n.

the sequence of events between one heartbeat and the next, normally occupying less than a second. See DIASTOLE, SYSTOLE.

Back  -    New Search

cardiac muscle n.

the specialized muscle of which the walls of the heart are composed. It consists of a network of branching elongated cells (fibres).

Back  -    New Search

cardiac reflex n.

reflex control of the heart rate.

Back  -    New Search

cardinal ligaments (Mackenrodt's ligaments) (kar-din-l) pl. n.

fan-shaped sheets of fascia that extend from the vagina and the cervix of the uterus to the walls of the pelvis.

Back  -    New Search

cardiology (kar-di-ol-ji) n.

the science concerned with the study of the structure, function, and diseases of the heart. nuclear c. the study and diagnosis of heart disease by the intravenous injection of a radionuclide, which emits gamma rays, enabling a gamma camera and computer to form an image of the heart. —cardiologist n.

Back  -    New Search

cardiomyopathy (kar-di-oh-my-op--thi) n.

any chronic disorder affecting the muscle of the heart. It may result in enlargement of the heart, heart failure, arrhythmias, and embolism.

Back  -    New Search

cardiomyoplasty (kar-di-oh-my-oh-plasti) n.

a surgical technique to replace or reinforce damaged cardiac muscle with skeletal muscle.

Back  -    New Search

cardiomyotomy (Heller's operation) (kar-di-oh-my-ot-mi) n.

surgical splitting of the muscular ring at the junction of the stomach and oesophagus to relieve achalasia.

Back  -    New Search

cardiopathy (kar-di-op--thi) n.

any disease of the heart.
—cardiopathic (kar-di-oh-path-ik) adj.

Back  -    New Search

cardioplegia (kar-di-oh-plee-ji) n.

a technique in which the heart is stopped by injecting it with a solution of salts, by hypothermia, or by an electrical stimulus. This has enabled complex cardiac surgery and transplants to be performed safely.

Back  -    New Search

cardiopulmonary bypass (kar-di-oh-pul-mn-er-i) n.

a method by which the circulation to the body is maintained while the heart is deliberately stopped during heart surgery. The function of the heart and lungs is carried out by a pump-oxygenator (heart-lung machine) until the natural circulation is restored.

Back  -    New Search

cardiospasm (kar-di-oh-spazm) n.

see ACHALASIA.

Back  -    New Search

cardiotocograph (kar-di-oh-tok-oh-graf) n.

the instrument used in cardiotocography to produce a cardiotocogram , the graphic printout of the measurements obtained.

Back  -    New Search

cardiotocography (kar-di-oh-t-kog-rfi) n.

the electronic monitoring of the fetal heart rate and rhythm, either by an external microphone or transducer or by applying an electrode to the fetal scalp, recording the fetal ECG and hence the heart rate. The procedure also includes a measurement of the strength and frequency of uterine contractions by means of an external transducer or an intrauterine catheter.

Back  -    New Search

cardiotomy syndrome (postcardiotomy syndrome) (kar-di-ot-mi) n.

a condition that may develop after surgery to the heart and the pericardium and is characterized by fever and pericarditis. Pneumonia and pleurisy may form part of the syndrome.

Back  -    New Search

cardiovascular system (circulatory system) (kar-di-oh-vas-kew-ler) n.

the heart together with two networks of blood vessels - the systemic circulation and the pulmonary circulation. The cardiovascular system effects the circulation of blood around the body, which brings about transport of nutrients and oxygen to the tissues and the removal of waste products.

Back  -    New Search

cardioversion (countershock) (kar-di-oh-ver-shn) n.

a method of restoring the normal rhythm of the heart in patients with increased heart rate caused by arrhythmia. A controlled direct-current shock is given through electrodes placed on the chest wall of the anaesthetized patient. The apparatus is called a cardiovertor .

Back  -    New Search

care assistant (kair) n.

a person who assists with the general care of a patient, usually assisting a nurse or social worker with care of the vulnerable elderly in the community.

Back  -    New Search

care plan n.

see PLANNING.

Back  -    New Search

caries (kair-eez) n.

decay and crumbling of the substance of a bone. dental c. tooth decay, caused by the metabolism of the bacteria in plaque attached to the surface of the tooth. Acid formed by bacterial breakdown of sugar in the diet gradually etches and decomposes the enamel of the tooth; if left unrepaired, it spreads in and progressively destroys the tooth completely.
—carious adj.

Back  -    New Search

carina (k-ree-n) n.

a keel-like structure, such as the keel-shaped cartilage at the bifurcation of the trachea into the two main bronchi.

Back  -    New Search

cariogenic (kair-i-oh-jen-ik) adj.

causing caries, particularly dental caries.

Back  -    New Search

carminative (kar-min--tiv) n.

a drug that relieves flatulence, used to treat gastric discomfort and colic.

Back  -    New Search

carmustine (BCNU) (kar-mus-teen) n.

an alkylating agent used in the treatment of certain cancers, including lymphomas and brain tumours.

Back  -    New Search

carneous mole (kar-nis) n.

a fleshy mass in the uterus consisting of pieces of placenta and products of conception that have not been expelled after abortion.

Back  -    New Search

carotenaemia (ka-r-ti-nee-mi) n.

see XANTHAEMIA.

Back  -    New Search

carotene (ka-r-teen) n.

a yellow, orange, red, or brown plant pigment; one of the carotenoids. The most important form, ß-carotene, is an antioxidant and can be converted in the body to retinol (vitamin A).

Back  -    New Search

carotenoid (k-rot-in-oid) n.

any one of a group of about 100 naturally occurring yellow to red pigments found mostly in plants.

Back  -    New Search

carotid artery (k-rot-id) n.

either of the two main arteries in the neck whose branches supply the head and neck.

Back  -    New Search

carotid-artery stenosis (carotid stenosis) n.

narrowing of the carotid artery, which reduces the supply of blood to the brain and is a cause of strokes. Many cases can be treated by surgical excision or bypass of the narrowed segment (see also ENDARTERECTOMY).

Back  -    New Search

carotid body n.

a small mass of tissue in the carotid sinus containing chemoreceptors that monitor levels of oxygen, carbon dioxide, and hydrogen ions in the blood.

Back  -    New Search

carotid sinus n.

a pocket in the wall of the carotid artery, at its division in the neck, containing receptors that monitor blood pressure (baroreceptors).

Back  -    New Search

carp- (carpo-) prefix

denoting the wrist (carpus).

Back  -    New Search

carpal (kar-pl)

1 adj. relating to the wrist.

2 n. any of the bones forming the carpus.
Top

Back  -    New Search

carpal tunnel syndrome n.

tingling, numbness, and pain affecting all the hand except the little finger; there may be weakness of the thumb. It is caused by pressure on the median nerve as it passes through the wrist.

Back  -    New Search

carphology (floccillation) (kar-fol-ji) n.

plucking at the bedclothes by a delirious patient. This is often a sign of extreme exhaustion and may be the prelude to death.

Back  -    New Search

carpopedal spasm (kar-poh-pee-d'l) n.

see SPASM.

Back  -    New Search

carpus (kar-ps) n.

the eight bones of the wrist (see illustration). The carpus articulates with the metacarpals distally and with the ulna and radius proximally.

Back  -    New Search

carrier (ka-ri-er) n.

1 a person who harbours the microorganisms causing a particular disease without experiencing signs or symptoms of infection and who can transmit the disease to others.

2 (in genetics) a person who bears a gene for an abnormal trait without showing signs of the disorder.
Top

3 an animal, usually an insect, that passively transmits infectious organisms from one animal to another or from an animal to a human being. See also VECTOR.
Top

Back  -    New Search

cartilage (kar-til-ij) n.

a dense connective tissue, consisting chiefly of chondroitin sulphate, that is capable of withstanding considerable pressure. In the fetus and infant cartilage occurs in many parts of the body, but most of this cartilage disappears during development. Cartilage is the precursor of bone following a fracture (see CALLUS). elastic c. cartilage occurring in the external ear. fibrocartilage cartilage occurring in the intervertebral discs and tendons. hyaline c. cartilage found in the costal cartilages, larynx, trachea, bronchi, nose, and covering the surface of the bones at joints.

Back  -    New Search

caruncle (ka-rng-kl) n.

a small red fleshy swelling. hymenal c. a caruncle occurring around the mucous membrane lining the vaginal opening. lacrimal c. the red prominence at the inner angle of the eye.

Back  -    New Search

cascara (cascara sagrada) (kas-kar-) n.

the dried bark of an American buckthorn, Rhamnus purshiana, used as a laxative.

Back  -    New Search

caseation (kay-si-ay-shn) n.

the breakdown of diseased tissue into a dry cheeselike mass: a type of degeneration associated with tubercular lesions.

Back  -    New Search

casein (kay-si-in) n.

a milk protein. Casein is precipitated out of milk in acid conditions or by the action of rennin. It is very easily prepared and is useful as a protein supplement, particularly in the treatment of malnutrition.

Back  -    New Search

caseinogen (kay-si-in--jin) n.

a protein, present in milk, that is converted into casein by the action of rennin.

Back  -    New Search

Casey's model (kay-siz) n.

a model of family-centred care for paediatric nursing in which the care of children (well or sick) is regarded as best carried out by their families, with varying degrees of assistance from members of a suitably qualified health-care team as necessary. See also NURSING MODELS. [A. Casey (1951– ), British nurse theorist]

Back  -    New Search

cast (kahst) n.

1 a rigid casing designed to immobilize part of the body, usually a fractured limb, until healing has progressed sufficiently. It is made of plastic or with open-woven bandage impregnated with plaster of Paris and applied while wet.

2 a mass of dead cellular, fatty, and other material that forms within a body cavity and takes its shape. It may then be released and appear elsewhere.
Top

Back  -    New Search

castor oil (kahst-er) n.

an irritant laxative administered by mouth to relieve constipation. It is also used with zinc as an ointment to treat skin irritations, such as napkin rash and bedsores.

Back  -    New Search

castration (kas-tray-shn) n.

removal of the sex glands (the testes or the ovaries).

Back  -    New Search

CAT n.

computerized axial tomography, now referred to as CT (see COMPUTERIZED TOMOGRAPHY).

Back  -    New Search

cata- prefix

denoting downward or against.

Back  -    New Search

catabolism (k-tab-l-izm) n.

the chemical decomposition of complex substances by the body to form simpler ones, accompanied by the release of energy. See also METABOLISM.
—catabolic (kat--bol-ik) adj.

Back  -    New Search

catagen (kat--jn) n.

see ANAGEN.

Back  -    New Search

catalase (kat--layz) n.

an enzyme, present in many cells (including red blood cells and liver cells), that catalyses the breakdown of hydrogen peroxide.

Back  -    New Search

catalepsy (kat--lep-si) n.

the abnormal maintenance of postures or physical attitudes, occurring in catatonia.

Back  -    New Search

catalyst (kat--list) n.

a substance that alters the rate of a chemical reaction but is itself unchanged at the end of the reaction. The catalysts of biochemical reactions are the enzymes.

Back  -    New Search

cataphoresis (kat--f-ree-sis) n.

the introduction into the tissues of positively charged ionized substances (cations) by the use of a direct electric current. See IONTOPHORESIS.

Back  -    New Search

cataplexy (kat--pleks-i) n.

a recurrent condition in which the patient suddenly collapses to the ground without loss of consciousness. Any strong emotion can provoke an attack.

Back  -    New Search

cataract (kat--rakt) n.

any opacity in the lens of the eye, resulting in blurred vision. Cataracts most commonly occur in the elderly (senile c. ), but some are congenital or result from metabolic disease (such as diabetes) or from injury or exposure of the eye to harmful radiation.

Back  -    New Search

cataract extraction n.

surgical removal of a cataract from the eye. extracapsular c. e. removal of the cataract alone, leaving the lens capsule behind to support the remaining lens tissue. intracapsular c. e. removal of the whole lens, including the capsule that surrounds it.

Back  -    New Search

catarrh (k-tar) n.

the excessive secretion of thick phlegm or mucus by the mucous membrane of the nose, nasal sinuses, naso-pharynx, or air passages.

Back  -    New Search

catatonia (kat--toh-ni) n.

a state in which a person becomes mute or stu-porous or adopts bizarre postures (see also FLEXIBILITAS CEREA). Catatonia was once a noted feature of schizophrenia but is now hardly ever seen in developed countries. It remains common in Third World countries.
—catatonic adj.

Back  -    New Search

catchment area (kach-mnt) n.

the geographic area from which a hospital can expect to receive patients and on which in Britain the designated population of the hospital is based.

Back  -    New Search

catecholamines (kat--kol--meenz) pl. n.

a group of physiologically important substances, including adrenaline, nor-adrenaline, and dopamine, with different roles (mainly as neurotransmitters) in the functioning of the sympathetic and central nervous systems.

Back  -    New Search

catgut (kat-gut) n.

a natural fibrous material prepared from the tissues of animals, usually from sheep intestines, used to sew up wounds and tie off blood vessels during surgery. The catgut gradually dissolves and is absorbed by the tissues, so that the stitches do not have to be removed later.

Back  -    New Search

catharsis (k-thar-sis) n.

purging or cleansing out of the bowels by giving the patient a laxative (cathartic) to stimulate intestinal activity.

Back  -    New Search

cathartic (k-thar-tik) n.

see LAXATIVE.

Back  -    New Search

catheter (kath-it-er) n.

a flexible tube for insertion into a narrow opening so that fluids may be introduced or removed. urinary c. a catheter passed into the bladder through the urethra to allow drainage of urine in certain disorders and to empty the bladder before abdominal operations.

Back  -    New Search

catheterization (kath-it-er-l-zay-shn) n.

the introduction of a catheter into a hollow organ. arterial c. the introduction of a catheter into an artery, enabling the introduction of dyes for radiographic purposes, drugs to constrict or expand the vessels for treatment purposes, and insoluble microspheres to block the vessel and arrest haemorrhage or necrose tumours. cardiac c. the introduction of special catheters into the various chambers of the heart via the arteries and veins of the arms or legs. It provides data on pressures and blood flow within the various chambers of the heart. urethral c. the introduction of a catheter into the bladder in order to relieve obstruction to the outflow of urine (see also INTERMITTENT SELF-CATHETERIZATION).

Back  -    New Search

cation (kat-l-n) n.

a positively charged ion, which moves towards the cathode (negative electrode) when an electric current is passed through the solution containing it. Compare ANION.

Back  -    New Search

cat-scratch fever (kat-skrach) n.

an infectious disease, possibly viral in origin, transmitted to man following injury to the skin by a cat scratch, splinter, or thorn. The injury becomes inflamed and mild fever and swelling of the lymph nodes (usually those closest to the wound) develop about a week after infection.

Back  -    New Search

cauda (kaw-d) n.

a tail-like structure. c. equina a bundle of nerve roots from the lumbar, sacral, and coccygeal spinal nerves that descend from the spinal cord to their respective openings in the vertebral column.

Back  -    New Search

caudal (kaw-d'l) adj.

relating to the lower part or tail end of the body.

Back  -    New Search

caul (kawl) n.

1 (in obstetrics) a membrane, part of the amnion, that may surround an infant at birth.

2 (in anatomy) see OMENTUM.
Top

Back  -    New Search

causal agent (kaw-zl) n.

a factor associated with the definitive onset of an illness (or other response, including an accident). Examples of causal agents are bacteria, trauma, and noxious agents.

Back  -    New Search

causalgia (kaw-zal-ji) n.

an intensely unpleasant burning pain felt in a limb where there has been partial damage to the sympathetic and somatic sensory nerves.

Back  -    New Search

caustic (kaw-stik) n.

an agent, such as silver nitrate, that causes irritation and burning and destroys tissue. Caustic agents may be used to remove dead skin, warts, etc.

Back  -    New Search

cauterize (kaw-t-ryz) vb.

to destroy tissues by direct application of a heated instrument (known as a cautery ): used for the removal of small warts or other growths and also to stop bleeding from small vessels.
—cautery n.

Back  -    New Search

cavernosography (kav-er-noh-sog-rfi) n.

a radiological examination of the penis that entails the infusion of radiopaque contrast material into the corpora cavernosa of the penis via a small butterfly needle. X-rays taken during the infusion give information regarding the veins draining the penis.

Back  -    New Search

cavernosometry (kav-er-noh-som-itri) n.

the measurement of pressure within the corpora cavernosa of the penis during infusion. The flow rate required to produce an erection is recorded and also the flow necessary to maintain the induced erection. The examination is important in the investigation of failure of erection and impotence.

Back  -    New Search

cavernous breath sounds (amphoric breath sounds) (kav-er-ns) pl. n.

hollow breath sounds heard over cavities in the lung.

Back  -    New Search

cavernous sinus n.

one of the paired cavities within the sphenoid bone, at the base of the skull behind the eye sockets, into which blood drains from the brain, eye, nose, and upper cheek before leaving the skull through connections with the internal jugular and facial veins.

Back  -    New Search

cavity (kav-iti) n.

1 (in anatomy) a hollow enclosed area; for example, the abdominal cavity or the buccal cavity (mouth).

2 (in dentistry) the hole in a tooth caused by caries or abrasion or formed by a dentist to retain a filling.
Top

Back  -    New Search

C cells pl. n.

parafollicular cells of the thyroid gland, which produce calcitonin.

Back  -    New Search

CD4 n.

a surface antigen on helper T-cells that is particularly important for immune resistance to viruses; progressive reduction of CD4-bearing T-cells reflects the progression of AIDS.

Back  -    New Search

CDH n.

see CONGENITAL DISLOCATION OF THE HIP.

Back  -    New Search

cefaclor (sef--klor) n.

a cephalosporin antibiotic that is administered by mouth for the treatment of otitis media, upper and lower respiratory-tract infections, urinary-tract infections, and skin infections. Trade name: Distaclor .

Back  -    New Search

cefadroxil (sef--droks-il) n.

a cephalosporin antibiotic administered by mouth for the treatment of urinary-tract infections, skin infections, pharyngitis, and tonsillitis. Trade name: Baxan .

Back  -    New Search

-cele (-coele) suffix

denoting swelling, hernia, or tumour.

Back  -    New Search

cell (sel) n.

the basic unit of all living organisms, which can reproduce itself exactly (see MITOSIS). Cells contain cytoplasm, in which are suspended a nucleus and other structures (organelles) specialized to carry out particular activities in the cell. Complex organisms such as man are built up of millions of cells that are specially adapted to carry out particular functions. See illustration.

Back  -    New Search

cell division n.

reproduction of cells by division first of the chromosomes (karyokinesis) and then of the cytoplasm (cytokinesis). Cell division to produce more body (somatic) cells is by mitosis; cell division during the formation of gametes is by meiosis.

Back  -    New Search

cellulitis (sel-yoo-ly-tis) n.

an infection of the deep dermis of the skin by ß-haemolytic streptococci. It is most common on the lower legs and there may be associated lymphangitis and lymphadenitis. It is otherwise similar to erysipelas, but the margins are less clearly defined because the infection is deeper.

Back  -    New Search

cellulose (sel-yoo-lohz) n.

a carbohydrate consisting of linked glucose units. It is an important constituent of plant cell walls. Cellulose cannot be digested by man and is a component of dietary fibre (roughage).

Back  -    New Search

Celsius temperature (centigrade temperature) (sel-si-s) n.

temperature expressed on a scale in which the melting point of ice is assigned a temperature of 0° and the boiling point of water a temperature of 100°. The formula for converting from Celsius (C) to Fahrenheit (F) is: F = 9/5C + 32. See also FAHRENHEIT TEMPERATURE. [A. Celsius (1701–44), Swedish astronomer]

Back  -    New Search

cement (si-ment) n.

1 any of a group of materials used in dentistry either as fillings or as lutes for crowns.

2 see CEMENTUM.
Top

Back  -    New Search

cementum (cement) (si-men-tm) n.

a thin layer of hard tissue on the surface of the root of a tooth. It anchors the fibres of the periodontal membrane to the tooth.

Back  -    New Search

censor (sen-ser) n.

(in psychology) the mechanism, postulated by Freud, that suppresses or modifies desires that are inappropriate or feared.

Back  -    New Search

-centesis suffix

denoting puncture or perforation.

Back  -    New Search

centi- prefix

denoting one hundredth or a hundred.

Back  -    New Search

centigrade temperature (sent-i-grayd) n.

see CELSIUS TEMPERATURE.

Back  -    New Search

centile chart (sen-tyl) n.

a graph with lines showing average measurements of height, weight, and head circumference compared with age and sex, against which a child's physical development can be assessed. The lines of growth on the graph are called centiles , and the number of a centile predicts the percentage of children who are below that measurement at a given age; for example, the 10th centile means that 10% of the age- and sex-matched population will be smaller and 90% will be bigger. Children whose growth lies outside the 97th or 3rd centiles may need to be investigated.

Back  -    New Search

centoxin (sen-toks-in) n.

a monoclonal antibody that neutralizes the effects of bacterial endotoxins. It is administered by injection in cases of dangerous bacterial infection with overwhelming toxicity.

Back  -    New Search

central nervous system (CNS) (sen-trl) n.

the brain and the spinal cord, as opposed to the peripheral nervous system. The CNS is responsible for the integration of all nervous activities.

Back  -    New Search

central venous pressure (CVP) n.

blood pressure in the right atrium, recorded by means of a catheter inserted into the vena cava and attached to a manometer. It is monitored particularly after heart surgery.

Back  -    New Search

centri- prefix

denoting centre.

Back  -    New Search

centrifugal (sen-tri-few-gl) adj.

moving away from a centre, as from the brain to the peripheral tissues.

Back  -    New Search

centrifuge (sen-tri-fewj) n.

a device for separating components of different densities in a liquid, using centrifugal force. The liquid is placed in special containers that are spun at high speed around a central axis.

Back  -    New Search

centriole (sen-tri-ohl) n.

a small particle found in the cytoplasm of cells, near the nucleus. Centrioles are involved in the formation of the spindle and aster during cell division.

Back  -    New Search

centripetal (sen-trip-it'l) adj.

moving towards a centre, as from the peripheral tissues to the brain.

Back  -    New Search

centromere (kinetochore) (sen-tr-meer) n.

the part of a chromosome that joins the two chromatids to each other and becomes attached to the spindle during mitosis and meiosis. When chromosome division takes place the centromeres split longitudinally.

Back  -    New Search

centrosome (centrosphere) (sen-tr-sohm) n.

an area of clear cytoplasm, found next to the nucleus in nondividing cells, that contains the centrioles.

Back  -    New Search

centrosphere (sen-tr-sfeer) n.

1 an area of clear cytoplasm seen in dividing cells around the poles of the spindle.

2 see CENTROSOME.
Top

Back  -    New Search

cephal- (cephalo-) prefix

denoting the head.

Back  -    New Search

cephalalgia (sef--lal-ji) n.

pain in the head; headache.

Back  -    New Search

cephalexin (sef--leks-in) n.

a cephalosporin antibiotic administered by mouth for the treatment of respiratory-tract and genitourinary-tract infections, bone and skin infections, and otitis media. Trade names: Ceporex , Keflex .

Back  -    New Search

cephalhaematoma (sef-l-heem--toh-m) n.

a swelling on the head caused by a collection of bloody fluid between one or more of the skull bones and its covering membrane (periosteum). It is most commonly seen in newborn infants delivered with the aid of forceps or subjected to pressures during passage through the birth canal. No treatment is necessary and the swelling disappears in a few months. If it is extensive, the blood in the fluid may break down, releasing bilirubin into the bloodstream and causing jaundice.

Back  -    New Search

cephalic (si-fal-ik) adj.

of or relating to the head.

Back  -    New Search

cephalic index n.

a measure of the shape of a skull, commonly used in craniometry.

Back  -    New Search

cephalic version n.

a procedure for turning a fetus that is lying in a breech or transverse position so that its head will enter the birth canal first.

Back  -    New Search

cephalocele (si-fal--seel) n.

protrusion of the contents of the skull through a defect in the bones of the skull. See NEURAL TUBE DEFECT.

Back  -    New Search

cephalogram (sef--loh-gram) n.

a special standardized X-ray picture that can be used to measure alterations in the growth of skull bones.

Back  -    New Search

cephalometry (sef--lom-itri) n.

the study of facial growth by examination of standardized lateral radiographs of the head. It is used mainly for diagnosis in orthodontics.

Back  -    New Search

cephalosporin (sef--loh-spo-rin) n.

any one of a group of semisynthetic antibiotics, derived from the mould Cephalosporium, which are effective against a wide range of microorganisms and are therefore used to treat a variety of infections (see CEFACLOR, CEFADROXIL, CEPHALEXIN, CEPHAZOLIN). Cross-sensitivity with penicillin may occur and the principal side-effects are allergic reactions and irritation of the digestive tract.

Back  -    New Search

cephazolin (sef--zoh-lin) n.

a semisynthetic antibiotic, given by intramuscular or intravenous injection in the treatment of a number of infections. See CEPHALOSPORIN. Trade name: Kefzol .

Back  -    New Search

cerclage (ser-klahzh) n.

see CERVICAL (CERCLAGE).

Back  -    New Search

cerebellar syndrome (Nonne's syndrome) (se-ri-bel-er) n.

see (CEREBELLAR) ATAXIA.

Back  -    New Search

cerebellum (se-ri-bel-m) n.

the largest part of the hindbrain, bulging back behind the pons and the medulla oblongata and overhung by the occipital lobes of the cerebrum. The cerebellum is essential for the maintenance of muscle tone, balance, and the synchronization of activity in groups of muscles under voluntary control, converting muscular contractions into smooth coordinated movement.
—cerebellar adj.

Back  -    New Search

cerebr- (cerebri-, cerebro-) prefix

denoting the cerebrum or brain.

Back  -    New Search

cerebral abscess (se-ri-brl) n.

see ABSCESS.

Back  -    New Search

cerebral aqueduct n.

see AQUEDUCT.

Back  -    New Search

cerebral cortex n.

the intricately folded outer layer of the cerebrum, making up some 40% of the brain by weight. It is directly responsible for consciousness, with essential roles in perception, memory, thought, mental ability, and intellect, and it is responsible for initiating voluntary activity.

Back  -    New Search

cerebral haemorrhage n.

bleeding from a cerebral blood vessel into the tissue of the brain. It is commonly caused by degenerative disease of the arteries and high blood pressure but may result from bleeding from congenital abnormalities of blood vessels. The symptoms vary from a transient weakness or numbness to profound coma and death. See also ATHEROMA, HYPERTENSION, STROKE.

Back  -    New Search

cerebral hemisphere n.

one of the two paired halves of the cerebrum.

Back  -    New Search

cerebral palsy n.

a nonprogressive disorder of movement resulting from damage to the brain before, during, or immediately after birth. It is often associated with other neurological and mental problems. The underlying brain damage is permanent. There are many causes, including birth injury, hypoxia, hypoglycaemia, jaundice, and infection. The most common disability is a spastic paralysis. Sensation is often affected, leading to a lack of balance, and intelligence, posture, and speech are frequently impaired. Contractures of the limbs may cause fixed abnormalities.

Back  -    New Search

cerebration (se-ri-bray-shn) n.

1 the functioning of the brain as a whole.

2 the unconscious activities of the brain.
Top

Back  -    New Search

cerebrospinal fever (spotted fever) (se-ri-broh-spy-nl) n.

see MENINGITIS.

Back  -    New Search

cerebrospinal fluid (CSF) n.

the clear watery fluid that surrounds and protects the brain and spinal cord. It is contained in the subarachnoid space and circulates in the ventricles of the brain and in the central canal of the spinal cord.

Back  -    New Search

cerebrovascular accident (se-ri-broh-vas-kew-ler) n.

the clinical syndrome accompanying a sudden and sometimes severe attack of cerebrovascular disease, which leads to a stroke.

Back  -    New Search

cerebrovascular disease n.

any disorder of the blood vessels of the brain and its covering membranes (meninges). Most cases are due to atheroma and/or hypertension, clinical effects being caused by rupture of diseased blood vessels or inadequacy of the blood supply to the brain, due to cerebral thrombosis or embolism.

Back  -    New Search

cerebrum (telencephalon) (se-ri-brm) n.

the largest and most highly developed part of the brain, composed of the two cerebral hemispheres, separated from each other by the longitudinal fissure in the midline and connected at the base by the corpus callosum. The cerebrum is responsible for the initiation and coordination of all voluntary activity in the body and for governing the functioning of lower parts of the nervous system.

—cerebral adj.

Back  -    New Search

cerumen (earwax) (si-roo-men) n.

the waxy material that is secreted by the sebaceous glands in the external auditory meatus of the outer ear.

Back  -    New Search

cervic- (cervico-) prefix

denoting 1 the neck.

2 the cervix, especially of the uterus.
Top

Back  -    New Search

cervical (ser-vy-kl) adj.

1 of or relating to the neck. c. vertebrae the seven bones making up the neck region of the backbone. See also (CERVICAL) FRACTURE, VERTEBRA.

2 of, relating to, or affecting the cervix of an organ, especially the cervix of the uterus. c. cancer cancer of the cervix of the uterus. The growth can be detected at an early stage by periodic microscopical examination of a cervical smear. c. cerclage a procedure to help prevent preterm delivery. It involves placing a stitch around the cervix of the uterus to keep it closed and reduce the possibility of preterm cervical dilatation and rupture of membranes. c. incompetence unnatural spontaneous dilatation of the cervix of the uterus during the second trimester of pregnancy. The membranes bulge and subsequently rupture, and the fetus is expelled prematurely. c. intraepithelial neoplasia see CIN. c. smear a specimen of cellular material, scraped from the cervix of the uterus, that is stained and examined under a microscope in order to detect cell changes indicating the presence of cancer. See also CIN.
Top

Back  -    New Search

cervicitis (ser-vi-sy-tis) n.

inflammation of the cervix of the uterus.

Back  -    New Search

cervix (ser-viks) n.

a necklike part. c. uteri the neck of the uterus, which projects into the vagina and contains the cervical canal.

Back  -    New Search

cestode (ses-tohd) n.

see TAPEWORM.

Back  -    New Search

cetrimide (set-ri-myd) n.

a detergent disinfectant, used for cleansing skin surfaces and wounds, sterilizing surgical instruments and babies' napkins, and in shampoos. Trade name: Cetavlon .

Back  -    New Search

chalazion (meibomian cyst) (k-lay-zi-n) n.

a swollen sebaceous gland in the eyelid, caused by chronic inflammation following blockage of the gland's duct.

Back  -    New Search

chalcosis (kal-koh-sis) n.

the deposition of copper in the tissues of the eye, usually resulting from the presence of a copper foreign body within the eye.

Back  -    New Search

chancre (shang-ker) n.

a painless ulcer that develops at the site where infection enters the body, e.g. on the lips, penis, urethra, or eyelid. It is the primary symptom of such infections as sleeping sickness and syphilis.

Back  -    New Search

chancroid (shank-roid) n.

see SOFT SORE.

Back  -    New Search

charcoal (char-kohl) n.

a fine black powder, a form of carbon that is the residue from the partial burning of wood and other organic materials. activated c. charcoal that has been treated to increase its properties as an adsorbent, used as an emergency antidote to various poisons.

Back  -    New Search

Charcot-Bouchard aneurysm (shar-koh boo-shard) n.

see ANEURYSM. [J. M. Charcot (1825–93), French neurologist; C. J. Bouchard (1837–1915), French physician]

Back  -    New Search

Charcot-Marie-Tooth disease (peroneal muscular atrophy, hereditary sensorimotor neuropathy) (m-ree tooth) n.

a group of inherited diseases of the peripheral nerves, now more commonly known as hereditary sensorimotor neuropathies , causing a gradually progressive weakness and wasting of the muscles of the legs and the lower part of the thighs. The hands and arms are eventually affected. [P. Marie (1853–1940), French physician; H. H. Tooth (1856–1925), British physician]

Back  -    New Search

Charcot's joint n.

a damaged, swollen, and deformed joint resulting from repeated minor injuries of which the patient is unaware because the nerves that normally register pain are not functioning. The condition may occur in syphilis, diabetes mellitus, and syringo-myelia.

Back  -    New Search

Charcot's triad n.

the combination of fever, rigors, and jaundice that indicates acute cholangitis.

Back  -    New Search

Charnley clamps (charn-li) pl. n.

an apparatus used to encourage arthrodesis between the ends of two bones on either side of a joint. Parallel pins driven through the bone ends are connected on each side of the joint by bolts bearing wing nuts; tightening of the screw arrangements forces the surfaces of the bones together. [Sir J. Charnley (1911–82), British orthopaedic surgeon]

Back  -    New Search

Chediak-Higashi syndrome (ched-i-ak hi-gash-i) n.

a rare fatal hereditary disease in children, inherited as an autosomal recessive condition, causing enlargement of the liver and spleen, albinism, and abnormalities of the eye. The cause is unknown but thought to be due to a disorder of glycolipid metabolism. [A. Chediak (20th century), Cuban physician; O. Higashi (20th century), Japanese paediatrician]

Back  -    New Search

cheil- (cheilo-) prefix

denoting the lip(s).

Back  -    New Search

cheilitis (ky-ly-tis) n.

inflammation of the lips. angular c. cheilitis that affects the angles of the lips and is often caused by a staphylococcal-candidal infection.

Back  -    New Search

cheiloplasty (ky-loh-plasti) n.

see LABIOPLASTY.

Back  -    New Search

cheiloschisis (ky-losk-i-sis) n.

see CLEFT LIP.

Back  -    New Search

cheilosis (ky-loh-sis) n.

swollen cracked bright-red lips. This is a common symptom of many nutritional disorders, including ariboflavinosis (vitamin B_2 deficiency).

Back  -    New Search

cheir- (cheiro-) prefix

denoting the hand(s).

Back  -    New Search

cheiropompholyx (ky-roh-pom-f-liks) n.

a type of eczema affecting the palms and fingers. See POMPHOLYX.

Back  -    New Search

chelating agent (kee-layt-ing) n.

a chemical compound that forms complexes by binding metal ions. Some chelating agents, including desferrioxamine and penicillamine, are drugs used to treat metal poisoning: the metal is bound to the drug and excreted safely.

Back  -    New Search

chem- (chemo-) prefix

denoting chemical or chemistry.

Back  -    New Search

chemoreceptor (kee-moh-ri-sep-ter) n.

a cell or group of cells that responds to the presence of specific chemical compounds by initiating an impulse in a sensory nerve. Chemoreceptors are found in the taste buds and in the mucous membranes of the nose. See also RECEPTOR.

Back  -    New Search

chemosis (ki-moh-sis) n.

swelling (oedema) of the conjunctiva.

Back  -    New Search

chemotaxis (kee-moh-taks-iss) n.

movement of a cell or organism in response to the stimulus of a gradient of chemical concentration.

Back  -    New Search

chemotherapy (kee-moh-th'e-r-pi) n.

the prevention or treatment of disease by the use of chemical substances. The term is sometimes restricted to the treatment of infectious diseases with antibiotics and other drugs or to the control of cancer with antimetabolites and similar drugs (in contrast to radiotherapy).

Back  -    New Search

chenodeoxycholic acid (kee-noh-dee-oks-i-koh-lik) n.

a drug used in the treatment of cholesterol gallstones, which it gradually dissolves. It is administered by mouth. Trade names: Chendol , Chenofalk , Chenocedon .

Back  -    New Search

cherry angioma (che-ri) n.

see ANGIOMA.

Back  -    New Search

chest (chest) n.

see THORAX.

Back  -    New Search

Cheyne-Stokes respiration (chayn-stohks) n.

a striking form of breathing in which there is a cyclical variation in the rate, which becomes slower until breathing stops for several seconds before speeding up to a peak and then slowing again. It occurs particularly in states of coma. [J. Cheyne (1777–1836), Scottish physician; W. Stokes (1804–78), Irish physician]

Back  -    New Search

chiasma (ky-az-m) n. (pl. chiasmata)

see OPTIC (CHIASMA).

Back  -    New Search

chickenpox (chik-in-poks) n.

a highly infectious disease caused by the varicellazoster virus (a herpesvirus), which is transmitted by airborne droplets. Symptoms are mild fever followed by an itchy rash of red pimples that spread from the trunk to the face, scalp, and limbs. These develop into vesicles and then scabs, which drop off after about 12 days. The patient is infectious from the onset of symptoms until all the spots have gone. Medical name: varicella .

Back  -    New Search

Chief Administrative Medical Officer n.

a public health physician at area level under the NHS (Scotland) Act and the terms of the NHS Act applicable to Wales.

Back  -    New Search

Chief Nursing Officer n.

the government's chief nursing adviser, who is responsible for providing an expert professional contribution and advice on nursing, midwifery, and health visiting matters to ministers and senior officials.

Back  -    New Search

chilblains (perniosis) (chil-blaynz) pl. n.

dusky red itchy swellings that develop on the extremities in cold weather. They usually settle in two weeks but treatment with nifedipine is helpful in severe cases.

Back  -    New Search

child abuse (chyld) n.

the maltreatment of children. It may take the form of sexual abuse , when a child is involved in sexual activity by an adult; physical abuse , when physical injury is caused by cruelty or undue punishment (see NONACCIDENTAL INJURY); neglect , when basic physical provision for needs is lacking; and emotional abuse , when lack of affection and/or hostility from caregivers damage a child's emotional development.

Back  -    New Search

childbirth (chyld-berth) n.

see LABOUR.

Back  -    New Search

child health clinic n.

(in Britain) a special clinic for the routine care of infants and preschool children. The service provides screening tests for such conditions as congenital dislocation of hips, suppressed squint, thyroid insufficiency, and impaired speech and/or hearing, education for mothers (especially those having their first child) in feeding techniques and hygiene, and immunizations against infectious diseases.

Back  -    New Search

chir- (chiro-) prefix

denoting the hand(s). See also CHEIR-.

Back  -    New Search

chiropody (podiatry) (ki-rop-di) n.

the study and care of the foot, including its normal structure, its diseases, and their treatment.
—chiropodist n.

Back  -    New Search

chiropractic (ky-r-prak-tik) n.

a system of treating diseases by manipulation, mainly of the vertebrae of the backbone. It is based on the theory that nearly all disorders can be traced to the incorrect alignment of bones, with consequent malfunctioning of nerves and muscle throughout the body.
—chiropractor (ky-r-prak-ter) n.

Back  -    New Search

Chlamydia (kl-mid-i) n.

a genus of virus-like bacteria that cause disease in man and birds. C. psittaci the cause of psittacosis. C. trachomatis the causative agent of the eye disease trachoma and a common cause of sexually transmitted infections (see URETHRITIS).
—chlamydial adj.

Back  -    New Search

chloasma (melasma) (kloh-az-m) n.

ill-defined symmetrical brown patches on the cheeks or elsewhere on the face. Chloasma is a photosensitivity reaction in women on combined oral contraceptive pills or who are pregnant; very rarely it occurs in men.

Back  -    New Search

chlor- (chloro-) prefix

denoting 1 chlorine or chlorides.

2 green.
Top

Back  -    New Search

chloracne (klor-ak-ni) n.

an occupational acne-like skin disorder that occurs after regular contact with chlorinated hydrocarbons.

Back  -    New Search

chloral hydrate (klor-l hy-drayt) n.

a sedative and hypnotic drug used, mainly in children and the elderly, to induce sleep or as a daytime sedative. It is usually given by mouth as a syrup, although it can be administered rectally. Trade names: Noctec , Welldorm elixir .

Back  -    New Search

chlorambucil (klor-am-bew-sil) n.

a drug that destroys cancer cells. It is given by mouth and used mainly in the treatment of chronic leukaemias. Prolonged large doses may cause damage to the bone marrow. Trade name: Leukeran .

Back  -    New Search

chloramphenicol (klor-am-fen-i-kol) n.

an antibiotic that is effective against a wide variety of microorganisms. However, due to its serious side-effects, especially damage to the bone marrow, it is usually reserved for serious infections (such as typhoid fever) when less toxic drugs are ineffective. It is also used, in the form of eye drops or ointment, to treat bacterial conjunctivitis. Trade names: Chloromycetin , Kemicetine .

Back  -    New Search

chlorbutol (klor-bew-tol) n.

an antibacterial and antifungal agent used in injection solutions, in eye and nose drops, in powder form for irritational skin conditions, and as a gargle or mouthwash (combined with chlorhexidine).

Back  -    New Search

chlordiazepoxide (klor-dy-az-i-pok-syd) n.

a sedative and tranquillizing drug with muscle relaxant properties, administered by mouth or injection. Trade names: Librium , Diapox , Elenium . See also TRANQUILLIZER.

Back  -    New Search

chlorhexidine (klor-heks-i-deen) n.

an antiseptic used in solutions, creams, gels, and lozenges as a general disinfectant for skin and mucous membranes, as a preservative (for example, in eye drops), or as a mouthwash to control mouth infections. Trade name: Hibitane .

Back  -    New Search

chlorine (klor-een) n.

an extremely pungent gaseous element with antiseptic and bleaching properties. It is widely used to sterilize drinking water and purify swimming pools. In high concentrations it is toxic. Symbol: Cl.

Back  -    New Search

chlormethiazole (klor-mi-th'y--zohl) n.

a sedative and hypnotic drug administered by mouth or injection to treat insomnia in the elderly (when associated with confusion, agitation, and restlessness) and drug withdrawal symptoms (especially in alcoholism). Trade name: Heminevrin .

Back  -    New Search

chlorocresol (klo-roh-kree-sol) n.

an antiseptic derived from phenol, used as a general disinfectant and, at low concentrations, as a preservative in injections, creams, and lotions.

Back  -    New Search

chloroform (klo-r-form) n.

a volatile liquid formerly widely used as a general anaesthetic. Chloroform is now used only in low concentrations as a flavouring agent and preservative, in the treatment of flatulence, and in liniments as a rubefacient.

Back  -    New Search

chloroma (klo-roh-m) n.

a tumour that arises in association with myeloid leukaemia and consists essentially of a mass of leukaemic cells. A freshly cut specimen of the tumour appears green, but the colour rapidly disappears on exposure to air.

Back  -    New Search

chlorophenothane (klo-roh-feen--thayn) n.

see DDT.

Back  -    New Search

chlorophyll (klo-r-fil) n.

one of a group of green pigments, found in all green plants and some bacteria, that absorb light to provide energy for the synthesis of carbohydrates from carbon dioxide and water (photosynthesis).

Back  -    New Search

chloroquine (klo-roh-kween) n.

a drug used principally in the treatment and prevention of malaria but also used in rheumatoid arthritis, certain liver infections and skin conditions, and lupus erythematosus. It is administered by mouth or injection; a side-effect of prolonged use in large doses is eye damage. Trade names: Avloclor , Nivaquine .

Back  -    New Search

chlorothiazide (klo-roh-th'y--zyd) n.

a diuretic administered by mouth to treat fluid retention (oedema) and high blood pressure (hypertension). Trade name: Saluric .

Back  -    New Search

chloroxylenol (klo-roh-zy-li-nol) n.

an antiseptic, derived from phenol but less toxic and more selective in bactericidal activity, used mainly in solution as a skin disinfectant. Trade name: Dettol .

Back  -    New Search

chlorpheniramine (klor-fen-l--r-meen) n.

a potent antihistamine used to treat such allergies as hay fever, rhinitis, and urticaria. It is administered by mouth or, to relieve severe conditions, by injection. Trade name: Piriton .

Back  -    New Search

chlorpromazine (klor-prom--zeen) n.

a phenothiazine antipsychotic drug, administered by mouth or injection or as a rectal suppository. It is used in the treatment of schizophrenia and mania; it is also used to treat severe anxiety and agitation and to control nausea and vomiting. It also enhances the effects of analgesics and is used in terminal illness and preparation for anaesthesia. Trade name: Largactil .

Back  -    New Search

chlorpropamide (klor-proh-p-myd) n.

a drug that reduces blood sugar levels and is administered by mouth to treat noninsulin-dependent diabetes in adults. Trade name: Diabinese . See also SULPHONYLUREA.

Back  -    New Search

chlortetracycline (klor-tet-r-sy-kleen) n.

an antibiotic active against many bacteria and fungi. It is administered by mouth or injection or as ointment or cream (for skin and eye infections). Trade names: Aureomycin , Deteclo .

Back  -    New Search

chlorthalidone (klor-thal-i-dohn) n.

a thiazide diuretic administered by mouth to treat fluid retention (oedema) and high blood pressure (hypertension). Trade name: Hygroton .

Back  -    New Search

choana (koh--n) n. (pl. choanae)

a funnel-shaped opening, particularly either of the two openings between the nasal cavity and the pharynx.

Back  -    New Search

chocolate cyst (chok--lit) n.

a cyst filled with dark fluid, occurring in the ovary in endometriosis.

Back  -    New Search

chol- (chole-, cholo-) prefix

denoting bile.

Back  -    New Search

cholaemia (kol-eem-i) n.

the presence of bile or bile pigments in the blood. See JAUNDICE.

Back  -    New Search

cholagogue (kol--gog) n.

a drug that stimulates the flow of bile from the gall bladder and bile ducts into the duodenum.

Back  -    New Search

cholangiocarcinoma (kol-anji-oh-kar-sin-oh-m) n.

a malignant tumour of the bile ducts. It is particularly likely to occur at the junction of the two main bile ducts within the liver, causing obstructive jaundice.

Back  -    New Search

cholangiography (kol-anji-og-rfi) n.

X-ray examination of the bile ducts, used to demonstrate the site and nature of any obstruction to the ducts or to show the presence of stones within them. A medium that is opaque to X-rays is introduced into the ducts by injection into the bloodstream, the liver, the bile ducts themselves, or the duodenal opening of the ducts.

Back  -    New Search

cholangiolitis (kol-anji--ly-tis) n.

inflammation of the smallest bile ducts (cholangioles ). See CHOLANGITIS.

Back  -    New Search

cholangiopancreatography (kol-anji-oh-pank-ri--tog-rfi) n.

a method for outlining the bile ducts and pancreatic ducts with radiopaque dyes. endoscopic retrograde c. see ERCP. percutaneous transhepatic c. (PTC) cholangiopancreatography in which the dyes are introduced by a catheter inserted into the ducts from the surface of the skin.

Back  -    New Search

cholangitis (kol-an-jy-tis) n.

inflammation of the bile ducts, often caused by an obstruction in the ducts. Initial treatment is by antibiotics, but removal of the obstruction is essential for permanent cure.

Back  -    New Search

cholecalciferol (koli-kal-sif-er-ol) n.

see VITAMIN D.

Back  -    New Search

cholecyst- prefix

denoting the gall bladder.

Back  -    New Search

cholecystectomy (koli-sis-tek-tmi) n.

surgical removal of the gall bladder, usually for cholecystitis or gallstones.

Back  -    New Search

cholecystenterostomy (koli-sist-en-ter-ost-mi) n.

a surgical procedure in which the gall bladder is joined to the small intestine. It is performed in order to allow bile to pass from the liver to the intestine when the common bile duct is obstructed by an irremovable cause.

Back  -    New Search

cholecystitis (koli-sis-ty-tis) n.

inflammation of the gall bladder.

Back  -    New Search

cholecystoduodenostomy (koli-sis-toh-dew-oh-di-nost-mi) n.

a form of cholecystenterostomy in which the gall bladder is joined to the duodenum.

Back  -    New Search

cholecystogastrostomy (koli-sis-toh-gas-trost-mi) n.

a form of cholecystenterostomy in which the gall bladder is joined to the stomach. It is rarely performed.

Back  -    New Search

cholecystography (koli-sis-tog-rfi) n.

X-ray examination of the gall bladder. A compound opaque to X-rays is administered by mouth and an X-ray photograph (cholecystogram ) is taken.

Back  -    New Search

cholecystojejunostomy (koli-sis-toh-j-joo-nost-mi) n.

a form of cholecystenterostomy in which the gall bladder is joined to the jejunum.

Back  -    New Search

cholecystokinin (koli-sis-toh-ky-nin) n.

a hormone secreted by cells of the duodenum in response to the presence of partly digested food in the duodenum. It causes contraction of the gall bladder and expulsion of bile into the intestine and stimulates the production of digestive enzymes by the pancreas.

Back  -    New Search

cholecystolithiasis (koli-sis-toh-lith-l--sis) n.

see CHOLELITHIASIS.

Back  -    New Search

cholecystotomy (koli-sis-tot-mi) n.

a surgical operation in which the gall bladder is opened, usually to remove gallstones.

Back  -    New Search

choledoch- (choledocho-) prefix

denoting the common bile duct.

Back  -    New Search

choledocholithiasis (koli-dok-oh-lith-l--sis) n.

stones within the common bile duct. The stones usually form in the gall bladder and pass into the bile duct, but they may develop within the duct after cholecystectomy.

Back  -    New Search

choledochotomy (koli-d-kot-mi) n.

a surgical operation in which the common bile duct is opened, to search for or to remove stones within it.

Back  -    New Search

cholelithiasis (cholecystolithiasis) (koli-lith-l--sis) n.

the formation of stones in the gall bladder or bile duct (see GALLSTONE).

Back  -    New Search

cholelithotomy (koli-lith-ot-mi) n.

the surgical removal of gallstones by cholecystotomy.

Back  -    New Search

cholera (kol-er-) n.

an acute infection of the small intestine by the bacterium Vibrio cholerae, which causes severe vomiting and diarrhoea (known as ricewater stools ) leading to dehydration. The disease is contracted from contaminated food or drinking water and often occurs in epidemics. Initial treatment is concentrated on replacing the fluid loss by oral rehydration therapy; tetracycline eradicates the bacteria and hastens recovery. The mortality rate in untreated cases is over 50%. Vaccination against cholera is effective for only 6–9 months.

Back  -    New Search

choleresis (kol-er-ee-sis) n.

the production of bile by the liver.

Back  -    New Search

choleretic (kol-er-et-ik) n.

an agent that stimulates the secretion of bile by the liver thereby increasing the flow of bile.

Back  -    New Search

cholestasis (koli-stay-sis) n.

failure of normal amounts of bile to reach the intestine, resulting in obstructive jaundice. The symptoms are jaundice with dark urine, pale faeces, and usually itching (pruritus).

Back  -    New Search

cholesteatoma (koli-sti--toh-m) n.

a skin-lined sac containing debris from dead skin cells that grows from the eardrum into the mastoid bone. Unless treated (by mastoidectomy), it can carry infection to the brain, causing meningitis or a cerebral abscess.

Back  -    New Search

cholesterol (kl-est-er-ol) n.

a fatlike material (a sterol) present in the blood and most tissues, especially nervous tissue. Elevated blood concentration of cholesterol (hypercholesterolaemia ) is often associated with atheroma, of which cholesterol is a major component. Cholesterol is also a constituent of gallstones.

Back  -    New Search

cholesterosis (kl-est-er-oh-sis) n.

a form of chronic cholecystitis in which small crystals of cholesterol are deposited on the internal wall of the gall bladder. The crystals may enlarge to become gallstones.

Back  -    New Search

cholestyramine (koli-sty-r-meen) n.

a drug that binds with bile salts so that they are excreted. It is administered by mouth to relieve conditions due to irritant effects of bile salts – such as the itching that occurs in obstructive jaundice – and also to lower the blood levels of cholesterol and other fats. Trade names: Cuemid , Questran .

Back  -    New Search

cholic acid (cholalic acid) (kol-ik) n.

see BILE ACIDS.

Back  -    New Search

choline (koh-leen) n.

a basic compound important in the synthesis of phosphatidylcholine (lecithin) and other phospholipids and of acetylcholine. It is also involved in the transport of fat in the body. Choline is sometimes classed as a vitamin but, although it is essential for life, it can be synthesized in the body.

Back  -    New Search

cholinergic (koh-lin-er-jik) adj.

1 describing or relating to nerve fibres that release acetylcholine as a neurotransmitter. c. receptor a receptor at which acetylcholine acts to pass on messages from cholinergic nerve fibres.

2 describing drugs that mimic the actions of acetylcholine (see PARASYMPATHOMIMETIC). Compare ADRENERGIC.
Top

Back  -    New Search

cholinesterase (koh-lin-est-er-ayz) n.

an enzyme that breaks down a choline ester into its choline and acid components. The term usually refers to acetylcholinesterase , which breaks down the neurotransmitter acetylcholine into choline and acetic acid.

Back  -    New Search

choline theophyllinate (thi--fil-i-nayt) n.

a drug used to dilate the air passages in asthma and chronic bronchitis. It is administered by mouth and can cause digestive upsets and nausea. Trade name: Choledyl .

Back  -    New Search

choluria (kol-yoor-i) n.

bile in the urine, which occurs when the level of bile in the blood is raised, especially in obstructive jaundice.

Back  -    New Search

chondr- (chondro-) prefix

denoting cartilage.

Back  -    New Search

chondritis (kon-dry-tis) n.

any inflammatory condition affecting cartilage.

Back  -    New Search

chondroblast (kon-droh-blast) n.

a cell that produces the matrix of cartilage.

Back  -    New Search

chondroblastoma (kon-droh-blas-toh-m) n.

a tumour derived from chondroblasts, having the appearance of a mass of well-differentiated cartilage.

Back  -    New Search

chondroclast (kon-droh-klast) n.

a cell that is concerned with the absorption of cartilage.

Back  -    New Search

chondrocyte (kon-droh-syt) n.

a cartilage cell, found embedded in the matrix.

Back  -    New Search

chondroma (kon-droh-m) n.

a benign tumour of cartilage-forming cells, which may occur at the growing end of any bone but is found most commonly in the bones of the feet and hands.

Back  -    New Search

chondromalacia (kon-droh-m-lay-shi) n.

softening, inflammation, and degeneration of cartilage at a joint. c. patellae chondromalacia affecting the undersurface of the kneecap, resulting in pain in the front of the knee and grating, which is made worse by kneeling, squatting, or climbing stairs.

Back  -    New Search

chondrosarcoma (kon-droh-sar-koh-ma) n. (pl. chondrosarcomata)

a malignant tumour of cartilage cells, occurring in a bone.

Back  -    New Search

chord-(chordo-) prefix

denoting 1 a cord.

2 the notochord.
Top

Back  -    New Search

chorda (kor-da) n. (pl. chordae)

a cord, tendon, or nerve fibre. chordae tendineae stringlike processes in the heart that attach the margins of the mitral and tricuspid valve leaflets to projections of the wall of the ventricle (papillary muscles ).

Back  -    New Search

chordee (kor-dee) n.

acute angulation of the penis. It may occur as a result of Peyronie's disease or, in a child, of hypospadias.

Back  -    New Search

chordotomy (kor-dot-mi) n.

see CORDOTOMY.

Back  -    New Search

chorea (ko-ree-) n.

a jerky involuntary movement particularly affecting the head, face, or limbs. The symptoms are most commonly due to disease of the basal ganglia. Huntington's c. see HUNTINGTON'S DISEASE. Sydenham's c. chorea that affects children and is associated with rheumatic fever.

Back  -    New Search

chorion (kor-in) n.

the embryonic membrane that totally surrounds the embryo from the time of implantation.
—chorionic adj.

Back  -    New Search

chorionepithelioma (choriocarcinoma) (kor-i-n-ep-i-theel-i-oh-m) n.

a rare form of cancer originating in the chorion. It is a highly malignant tumour usually following a hydatidiform mole, although it may follow abortion or even a normal pregnancy.

Back  -    New Search

chorionic gonadotrophin (kor-i-on-ik) n.

see HUMAN CHORIONIC GONADOTROPHIN.

Back  -    New Search

chorionic villi pl. n.

see VILLUS.

Back  -    New Search

chorionic villus sampling (CVS) n.

a fetal monitoring technique in which a sample of chorionic villus is extracted through the cervix or abdomen under ultrasound visualization. The earliest recommended time for sampling is the ninth week of pregnancy. The cells so obtained are subjected to chromosomal and biochemical studies to determine if any abnormalities are present in the fetus. This enables the prenatal diagnosis of such congenital disorders as Down's syndrome and thalassaemia.

Back  -    New Search

chorioretinopathy (kor-i-oh-ret-in-op--thi) n.

any eye disease involving both the choroid and the retina. central serous c. shallow retinal detachment in the area of the macula due to leakage through the retinal pigment epithelium (see RETINA) into the subretinal space. The cause is unknown. It affects young adult males, causing reduced or distorted vision that usually settles in a few months.

Back  -    New Search

choroid (ko-roid) n.

the layer of the eyeball between the retina and the sclera. It contains blood vessels and a pigment that absorbs excess light and so prevents blurring of vision. See EYE.
—choroidal adj.

Back  -    New Search

choroidal detachment (k-roid-l) n.

the separation of the choroid from the sclera of the eye as a result of leakage of fluid from the vessels of the choroid. It occurs when pressure inside the eyeball is very low, usually after trauma or intraocular surgery.

Back  -    New Search

choroiditis (ko-roid-I-tis) n.

inflammation of the choroid layer of the eye. Vision becomes blurred but the eye is usually painless. See UVEITIS.

Back  -    New Search

choroidocyclitis (ko-roid-oh-sy-kly-tis) n.

inflammation of the choroid layer and the ciliary body of the eye.

Back  -    New Search

choroid plexus n.

a rich network of blood vessels, derived from those of the pia mater, in each of the brain's ventricles. It is responsible for the production of cerebrospinal fluid.

Back  -    New Search

Christmas disease (kris-ms) n.

a disorder that is identical in its effects to haemophilia, but is due to a deficiency of a different blood coagulation factor, Factor IX. [S. Christmas (20th century), in whom the factor was first identified]

Back  -    New Search

Christmas factor n.

see FACTOR IX.

Back  -    New Search

chrom- (chromo-) prefix

denoting colour or pigment.
—chromasia suffix denoting staining or pigmentation.

Back  -    New Search

chromat- (chromato-) prefix

denoting colour or pigmentation.

Back  -    New Search

chromatid (kroh-m-tid) n.

one of the two threadlike strands formed by longitudinal division of a chromosome during mitosis and meiosis. They remain attached at the centromere.

Back  -    New Search

chromatin (kroh-m-tin) n.

the material of a cell nucleus that stains with basic dyes and consists of DNA and protein: the substance of which the chromosomes are made.

Back  -    New Search

chromatography (kroh-m-tog-rfi) n.

any of several techniques for separating the components of a mixture by selective absorption. In two such techniques, widely used in medicine, a sample of the mixture is placed at the edge of a sheet of filter paper (paper c. ) or a column of a powdered absorbent (column c. ). The components of the mixture are absorbed to different extents and thus move along the paper or column at different rates.

Back  -    New Search

chromatolysis (kroh-m-tol-i-sis) n.

the dispersal or disintegration of the microscopic structures within the nerve cells that normally produce proteins. It is part of the cell's response to injury.

Back  -    New Search

chromatophore (kroh-m-t-for) n.

a cell containing pigment. In man chromatophores containing melanin are found in the skin, hair, and eyes.

Back  -    New Search

chromatosis (kroh-m-toh-sis) n.

abnormal pigmentation of the skin, as occurs in Addison's disease.

Back  -    New Search

chromic acid (kroh-mik) n.

a compound of chromium used in solution as a caustic for the removal of warts. Formula:
CrO_3
.

Back  -    New Search

chromosome (kroh-m-sohm) n.

one of the threadlike structures in a cell nucleus that carry the genetic information in the form of genes. It is composed of a long double filament of DNA coiled into a helix together with associated proteins. The nucleus of each human somatic cell contains 46 chromosomes, 23 being of maternal and 23 of paternal origin. See also CHROMATID, CENTROMERE, SEX CHROMOSOME.
—chromosomal adj.

Back  -    New Search

chronic (kron-ik) adj.

describing a disease of long duration involving very slow changes. Such disease is often of gradual onset. Compare ACUTE.
—chronicity (kron-iss-iti) n.

Back  -    New Search

chronic fatigue syndrome n.

a condition characterized by extreme disabling fatigue that has lasted for at least six months, is made worse by physical or mental exertion, does not resolve with bed rest, and cannot be attributed to other disorders. It is associated with one or more of the following: muscle pain or weakness, joint pain, poor coordination, sore throat, painful lymph nodes in the neck and armpits, and depression. The condition is also known as postviral fatigue syndrome and was formerly called myalgic encephalomyelitis (ME).

Back  -    New Search

Chronic Sick and Disabled Persons Act 1970 n.

(in Britain) an Act providing for the identification and care of those suffering from a chronic or degenerative disease for which there is no cure and which can be only partially alleviated by treatment.

Back  -    New Search

Churg-Strauss syndrome (cherg-strows) n.

a clinical syndrome comprising severe asthma associated with an increased eosinophil count in the peripheral blood and eosinophilic deposits in the small vessels of the lungs. It usually responds to oral corticosteroids. Untreated, it may result in severe and widespread systemic angiitis. [J. Churg (1910– ) and L. Strauss (1913– ), US pathologists]

Back  -    New Search

Chvostek's sign (vos-teks) n.

a spasm of the facial muscles elicited by lightly tapping the facial nerve. It is a sign of tetany. [F. Chvostek (1835–84), Austrian surgeon]

Back  -    New Search

chyle (kyl) n.

an alkaline milky liquid found within the lacteals after a period of absorption. It consists of lymph with a suspension of minute droplets of digested fats, which have been absorbed from the small intestine.

Back  -    New Search

chyluria (kyl-yoor-i) n.

the presence of chyle in the urine.

Back  -    New Search

chyme (kym) n.

the semiliquid acid mass that is the form in which food passes from the stomach to the small intestine. It is produced by the action of gastric juice and the churning of the stomach.

Back  -    New Search

chymotrypsin (ky-moh-trip-sin) n.

a protein-digesting enzyme (see PEPTIDASE). It is secreted by the pancreas in an inactive form, chymotrypsinogen , that is converted into chymotrypsin in the duodenum by the action of trypsin.

Back  -    New Search

chymotrypsinogen (ky-moh-trip-sin--jin) n.

see CHYMOTRYPSIN.

Back  -    New Search

cicatricial (sik--trish-l) adj.

associated with scarring. c. alopecia see ALOPECIA.

Back  -    New Search

-cide suffix

denoting killer or killing.

Back  -    New Search

ciliary body (sil-i-er-i) n.

the part of the eye that connects the choroid with the iris. It consists of three zones: the ciliary ring , which adjoins the choroid; the ciliary processes , a series of about 70 radial ridges behind the iris to which the suspensory ligament of the lens is attached; and the ciliary muscle , contraction of which alters the curvature of the lens (see ACCOMMODATION).

Back  -    New Search

cilium (sil-im) n. (pl. cilia)

1 a hairlike process, large numbers of which are found on certain epithelial cells, particularly the epithelium that lines the upper respiratory tract, and on certain protozoa.

2 an eyelash or eyelid.
Top

—ciliary adj.

Back  -    New Search

cimetidine (si-met-i-deen) n.

an H_2-receptor antagonist (see ANTIHISTAMINE) that reduces secretion of acid in the stomach and is administered by mouth or injection to treat digestive disorders such as stomach and duodenal ulcers, and gastrooesophageal reflux disease. Trade names: Dyspamet , Galenamet , Tagamet .

Back  -    New Search

Cimex (sy-meks) n.

see BED BUG.

Back  -    New Search

CIN (cervical intraepithelial neoplasia) n.

cellular changes in the cervix of the uterus preceding the invasive stages of cervical cancer. The CIN grading system distinguishes three stages: CIN 1 (mild dysplasia); CIN 2 (moderate dysplasia); and CIN 3 (severe dysplasia, carcinoma in situ).

Back  -    New Search

cinchocaine (sink--kayn) n.

a local anaesthetic used in dental and other operations and to relieve pain. It is applied directly to the skin or mucous membranes or injected at the site where anaesthesia is required or into the spine. Trade name: Nupercainal .

Back  -    New Search

cinchona (sing-koh-n) n.

the dried bark of Cinchona trees, formerly used in medicine to stimulate the appetite and to prevent haemorrhage and diarrhoea. Cinchona is the source of quinine.

Back  -    New Search

cinchonism (sink--nizm) n.

poisoning caused by an overdose of cinchona or the alkaloids quinine, quinidine, or cinchonine derived from it. The symptoms include ringing noises in the ears, dizziness, and blurring of vision.

Back  -    New Search

cineangiocardiography (sini-an-ji-oh-kar-di-og-rfi) n.

a form of angiocardiography in which the X-ray pictures are recorded on cine film. This allows the dynamic movements of the heart to be studied when the film is projected.

Back  -    New Search

cineradiography (sini-ray-di-og-rfi) n.

the technique of taking a rapid succession of X-ray photographs, to capture on film events that occur rapidly during a particular radiographic investigation.

Back  -    New Search

cingulectomy (sing-yoo-lek-tmi) n.

surgical excision of the cingulum, occasionally carried out as psychosurgery for intractable mental illness.

Back  -    New Search

cingulum (sing-yoo-lm) n. (pl. cingula)

a curved bundle of nerve fibres in each cerebral hemisphere, nearly encircling its connection with the corpus callosum. It is the part of the brain controlling anger and depression. See CEREBRUM.

Back  -    New Search

ciprofloxacin (sip-roh-floks--sin) n.

a broad-spectrum quinolone antibiotic that can be given orally and is particularly useful against Gram-negative bacteria, such as Pseudomonas, that are resistant to all other oral antibiotics. Trade name: Ciproxin .

Back  -    New Search

circadian rhythm (ser-kay-din) n.

the periodic rhythm, synchronized approximately to the 24-hour day/night cycle, seen in various metabolic activities of most living organisms (e.g. sleeping, hormone secretion).

Back  -    New Search

circle of Willis (ser-kl v wil-iss) n.

a circle on the undersurface of the brain formed by linked branches of the arteries that supply the brain. [T. Willis (1621–75), English anatomist]

Back  -    New Search

circulation (ser-kew-lay-shn) n.

1 the movement of a fluid in a circular course, especially the passage of blood through the cardiovascular system.

2 the system of vessels effecting this passage. pulmonary c. circulation of blood between the heart and lungs. Deoxygenated blood passes to the lungs from the right ventricle via the pulmonary artery; oxygenated blood returns to the left atrium via the pulmonary vein. systemic c. circulation of blood between the heart and all parts of the body except the lungs. Oxygenated blood leaves the aorta and deoxygenated blood returns into the vena cava. See also COLLATERAL CIRCULATION.
Top

—circulatory adj.

Back  -    New Search

circum- prefix

denoting around; surrounding.

Back  -    New Search

circumcision (ser-km-sizh-n) n.

surgical removal of the foreskin of the penis. This operation is usually performed for religious and ethnic reasons but is sometimes required for medical conditions, mainly phimosis and paraphimosis. female c. surgical removal of the clitoris, labia minora, and labia majora. See CLITORIDECTOMY, INFIBULATION.

Back  -    New Search

circumduction (ser-km-duk-shn) n.

a circular movement, such as that made by a limb.

Back  -    New Search

circumflex nerve (ser-km-fleks) n.

a mixed sensory and motor nerve of the upper arm. It arises from the fifth and sixth cervical segments of the spinal cord and is distributed to the deltoid muscle of the shoulder and the overlying skin.

Back  -    New Search

circumoral (ser-km-or-l) adj.

situated around the mouth.

Back  -    New Search

cirrhosis (si-roh-sis) n.

a condition in which the liver responds to injury or death of some of its cells by producing interlacing strands of fibrous tissue between which are nodules of regenerating cells. Causes include alcoholism (alcoholic c. ), viral hepatitis (postnecrotic c. ), chronic obstruction of the common bile duct (secondary biliary c. ), autoimmune diseases (primary biliary c. ), and chronic heart failure (cardiac c. ). Complications include portal hypertension, ascites, hepatic encephalopathy, and hepatoma.
—cirrhotic adj.

Back  -    New Search

cirs- (cirso-) prefix

denoting a varicose vein.

Back  -    New Search

cirsoid (ser-soid) adj.

describing the distended knotted appearance of a varicose vein.

Back  -    New Search

CIS n.

see CARCINOMA IN SITU.

Back  -    New Search

CISC n.

clean intermittent self-catheterization. See INTERMITTENT SELF-CATHETERIZATION.

Back  -    New Search

cisplatin (sis-plat-in) n.

a heavy-metal compound; a cytotoxic drug that impedes cell division by damaging DNA.
Administered intravenously, it is used in the treatment of testicular and ovarian tumours. Trade name: Neoplatin .

Back  -    New Search

cisterna (sis-ter-n) n. (pl. cisternae)

1 one of the enlarged spaces beneath the arachnoid that act as reservoirs for cerebrospinal fluid. c. magna the largest of the cisternae, lying beneath the cerebellum and behind the medulla oblongata.

2 a dilatation at the lower end of the thoracic duct, into which the great lymph ducts of the lower limbs drain.
Top

Back  -    New Search

citalopram (sit-al--pram) n.

an antidepressant drug that acts by prolonging the action of the neurotransmitter serotonin (5-hydroxytryptamine) in the brain (see SSRI). It is taken by mouth. Trade name: Cipramil .

Back  -    New Search

citric acid (sit-rik) n.

an organic acid found naturally in citrus fruits. Citric acid is formed in the first stage of the Krebs cycle. Formula:
CH_2(COOH)C(OH)(COOH)-CH_2COOH
.

Back  -    New Search

citric acid cycle n.

see KREBS CYCLE.

Back  -    New Search

Citrobacter (sit-roh-bak-ter) n.

a genus of Gram-negative anaerobic rod-shaped bacteria widely distributed in nature. The organisms cause infections of the intestinal and urinary tracts, gall bladder, and the meninges that are usually secondary, occurring in the elderly, newborn, debilitated, and immunocompromised.

Back  -    New Search

citrulline (sit-r-leen) n.

an amino acid produced by the liver as a by-product during the conversion of ammonia to urea.

Back  -    New Search

CJD n.

see CREUTZFELDT-JAKOB DISEASE.

Back  -    New Search

clamp (klamp) n.

a surgical instrument designed to compress a structure, such as a blood vessel or a cut end of the intestine. See illustration.

Back  -    New Search

claudication (klaw-di-kay-shn) n.

limping. intermittent c. a cramping pain in the calf and leg muscles, induced by exercise and relieved by rest, that is caused by an inadequate supply of blood to the affected muscles.

Back  -    New Search

claustrophobia (klaw-str-foh-bi) n.

a morbid fear of enclosed places. See also PHOBIA.

Back  -    New Search

clavicle (klav-i-kl) n.

the collar bone: a long slender curved bone, a pair of which form the front part of the shoulder girdle. Fracture of the clavicle is a common sports injury: the majority of cases require no treatment other than supporting the weight of the arm in a sling.
—clavicular (kl-vik-yoo-ler) adj.

Back  -    New Search

clavulanic acid (klav-yoo-lan-ik) n.

a drug that interferes with the enzymes (penicillinases) that inactivate many penicillin-type antibiotics, such as amoxycillin. Combined with the antibiotic, clavulanic acid can overcome drug resistance.

Back  -    New Search

clavus (klay-vs) n.

1 see CORN.

2 a sharp pain in the head, as if a nail were being driven in.
Top

Back  -    New Search

claw-foot (klaw-fuut) n.

an excessively arched foot, giving an unnaturally high instep. In most cases the cause is unknown, but the deformity may sometimes be due to an imbalance between the muscles flexing the toes and the shorter muscles that extend them. Medical name: pes cavus .

Back  -    New Search

claw-hand (klaw-hand) n.

flexion and contraction of the fingers with extension at the joints between the fingers and the hand, giving a claw-like appearance. Causes of claw-hand include injuries, syringomyelia, and leprosy. See also DUPUYTREN'S CONTRACTURE.

Back  -    New Search

cleavage (kleev-ij) n.

(in embryology) the process of repeated cell division of the fertilized egg to form a ball of cells that becomes the blastocyst.

Back  -    New Search

cleft lip (harelip) (kleft) n.

the congenital deformity of a cleft in the upper lip, on one or both sides of the midline. It is often associated with a cleft palate. Medical name: cheiloschisis .

Back  -    New Search

cleft palate n.

a fissure in the midline of the palate due to failure of the two sides to fuse in embryonic development. Only part of the palate may be affected, or the cleft may extend the full length with bilateral clefts at the front of the maxilla; it may be accompanied by a cleft lip and disturbance of tooth formation.

Back  -    New Search

cleid- (cleido-, clid-, clido-) prefix

denoting the clavicle (collar bone).

Back  -    New Search

cleidocranial dysostosis (kly-doh-kray-nil dis-os-toh-sis) n.

a congenital defect of bone formation in which the skull bones ossify imperfectly and the collar bones (clavicles) are absent.

Back  -    New Search

clemastine (klem--steen) n.

an antihistamine used for the treatment of symptoms of hay fever, urticaria, and angioneurotic oedema because of its drying effects. Trade names: Aller-eze , Tavegil .

Back  -    New Search

climacteric (kly-mak-ter-ik) n.

see MENOPAUSE. male c. declining sexual drive and fertility in men, usually occurring around or after middle age.

Back  -    New Search

clindamycin (klin-d-my-sin) n.

an antibiotic administered by mouth to treat serious bacterial infections. Trade name: Dalacin C.

Back  -    New Search

clinic (klin-ik) n.

1 an establishment or department of a hospital devoted to the treatment of particular diseases or the medical care of out-patients.

2 a gathering of instructors, students, and patients, usually in a hospital ward, for the examination and treatment of the patients.
Top

Back  -    New Search

clinical audit (klin-i-kl) n.

a process by which doctors, nurses, and other healthcare professionals systematically review the procedures used for diagnosis, care, and treatment, examining how associated resources are used and investigating the effects care has on the outcome and quality of life for the patient.

Back  -    New Search

clinical medicine n.

the branch of medicine dealing with the study of actual patients and the diagnosis and treatment of disease at the bedside, as opposed to the study of disease by pathology or other laboratory work.

Back  -    New Search

clinodactyly (klin-oh-dak-tili) n.

congenital inward bending of a finger, usually the little finger. Clinodactyly may affect both hands and may be found in association with other congenital malformations.

Back  -    New Search

clitoridectomy (klit-er-id-ek-tmi) n.

surgical removal of the clitoris.

Back  -    New Search

clitoris (klit-er-iss) n.

the female counterpart of the penis, which contains erectile tissue (see CORPUS (CAVERNOSUM)) but is unconnected with the urethra. It becomes erect under conditions of sexual stimulation.

Back  -    New Search

cloaca (kloh-ay-k) n.

the most posterior part of the embryonic hindgut. It becomes divided into the rectum and the urinogenital sinus.

Back  -    New Search

clofibrate (kloh-fy-brayt) n.

a drug that reduces the levels of blood lipids, including cholesterol, and is administered by mouth to treat atherosclerosis and angina. Trade name: Atromid-S .

Back  -    New Search

Clomid (kloh-mid) n.

see CLOMIPHENE.

Back  -    New Search

clomiphene (kloh-mi-feen) n.

a synthetic nonsteroidal compound (see ANTI-ANDROGEN) that induces ovulation and subsequent menstruation in women who fail to ovulate and stimulates increased ovulation (see SUPEROVULATION) for in vitro fertilization. Trade name: Clomid .

Back  -    New Search

clomipramine (kloh-mip-r-meen) n.

a drug administered by mouth or injection to treat various depressive states (see ANTI-DEPRESSANT). Trade name: Anafranil .

Back  -    New Search

clonazepam (kloh-naz--pam) n.

a drug with anticonvulsant properties, administered by mouth or injection to treat epilepsy and other conditions involving seizures. Trade name: Rivotril .

Back  -    New Search

clone (klohn)

1 n. a group of cells (usually bacteria) descended from a single cell by asexual reproduction and therefore genetically identical to each other and to the parent cell.

2 an organism derived from a single cell of its parent and therefore genetically identical to it. gene c. a group of identical genes produced by techniques of genetic engineering.
Top

3 vb. to form a clone.
Top

Back  -    New Search

clonic (klon-ik) adj.

of, relating to, or resembling clonus. The term is most commonly used to describe the rhythmical limb movements seen as part of a convulsive epileptic seizure (see EPILEPSY).

Back  -    New Search

clonidine (kloh-ni-deen) n.

a drug administered by mouth or injection to treat high blood pressure (hypertension) and migraine. Trade names: Catapres , Dixarit .

Back  -    New Search

clonus (kloh-ns) n.

rhythmical contraction of a muscle in response to a suddenly applied and then sustained stretch stimulus. It is most readily obtained at the ankle and is usually a sign of disease in the brain or spinal cord.

Back  -    New Search

clopamide (kloh-p-myd) n.

a diuretic administered by mouth to treat fluid retention (oedema) and high blood pressure (hypertension). Trade name: Viskaldix .

Back  -    New Search

Clostridium (klo-strid-im) n.

a genus of mostly Gram-positive anaerobic spore-forming rodlike bacteria commonly found in soil and in the intestinal tract of man and animals. C. botulinum a species that grows freely in badly preserved canned foods, producing a toxin causing serious food poisoning (see BOTULISM). C. tetani a species that causes tetanus on contamination of wounds. C. perfringens (Welch's bacillus ) a species that causes blood poisoning, food poisoning, and gas gangrene.

Back  -    New Search

clotrimazole (kloh-trim--zohl) n.

an antifungal drug used to treat all types of fungal skin infections (including ringworm) and vaginal infections. It is applied to the infected part as a cream or solution or as vaginal pessaries. Trade name: Canesten .

Back  -    New Search

clotting factors (klot-ing) pl. n.

see COAGULATION FACTORS.

Back  -    New Search

clotting time n.

see COAGULATION TIME.

Back  -    New Search

cloxacillin sodium (kloks--sil-in) n.

an antibiotic, derived from penicillin, administered by mouth or injection to treat many bacterial infections. Trade name: Orbenin .

Back  -    New Search

clozapine (kloz--peen) n.

an atypical antipsychotic drug used in the treatment of schizophrenia and other disorders resistant to conventional antipsychotics. Administered by mouth, it is notable for the absence of tremors and repetitive movements that are associated with other antipsychotic drugs. In a few cases it may depress levels of white blood cells. Trade name: Clozaril .

Back  -    New Search

clubbing (klub-ing) n.

thickening of the tissues at the bases of the finger and toe nails so that the normal angle between the nail and the digit is filled in. In extreme cases the digit end becomes bulbous like a club or drumstick. Clubbing is seen in some diseases of the heart and respiratory system and as a harmless congenital abnormality.

Back  -    New Search

club-foot (klub-fuut) n.

see TALIPES.

Back  -    New Search

clumping (klump-ing) n.

see AGGLUTINATION.

Back  -    New Search

cluttering (klut-er-ing) n.

an erratic unrhythmical way of speaking in rapid jerky bursts. It can make speech hard to understand, and speech therapy is usually helpful. Unlike stammering, there are no repetitions or prolonged hesitations of speech.

Back  -    New Search

Clutton's joint (klu-t'nz) n.

a swollen joint in a child, usually the knee, caused by inflammation of the synovial membranes due to congenital syphilis. [H. H. Clutton (1850–1909), British surgeon]

Back  -    New Search

CMF n.

cyclophosphamide, methotrexate, 5-fluorouracil: the combination used in standard chemotherapy for cancer.

Back  -    New Search

CMV n.

see CYTOMEGALOVIRUS.

Back  -    New Search

CNS n.

see CENTRAL NERVOUS SYSTEM.

Back  -    New Search

coagulant (koh-ag-yoo-lnt) n.

any substance capable of converting blood from a liquid to a solid state. See BLOOD COAGULATION.

Back  -    New Search

coagulase (koh-ag-yoo-layz) n.

an enzyme, formed by disease-producing varieties of certain bacteria of the genus Staphylococcus, that causes blood plasma to coagulate. Staphylococci that are positive when tested for coagulase production are classified as belonging to the species Staphylococcus aureus.

Back  -    New Search

coagulation (koh-ag-yoo-lay-shn) n.

the process by which a colloidal liquid changes to a jelly-like mass. See BLOOD COAGULATION.

Back  -    New Search

coagulation factors (clotting factors) pl. n.

a group of substances present in blood plasma that are responsible for the conversion of blood from a liquid to a solid state (see BLOOD COAGULATION).
Although they have specific names, most coagulation factors are referred to by an agreed set of Roman numerals (see FACTOR VIII, FACTOR IX, FACTOR XI).

Back  -    New Search

coagulation time (clotting time) n.

the time taken for blood or blood plasma to coagulate (see BLOOD COAGULATION).

Back  -    New Search

coagulum (koh-ag-yoo-lm) n.

a mass of coagulated matter, such as that formed when blood clots.

Back  -    New Search

coalesce (koh--less) vb.

to grow together or unite.
—coalescence n.

Back  -    New Search

coal-worker's pneumoconiosis (anthracosis) (kohl-wer-kerz) n.

a lung disease caused by coal dust. It affects mainly coal miners but also other exposed workers, such as lightermen, if the lungs' capacity to accommodate and remove the particles is exceeded. See PNEUMOCONIOSIS.

Back  -    New Search

coarctation (koh-ark-tay-shn) n.

(of the aorta) a congenital narrowing of a short segment of the aorta, resulting in high blood pressure in the upper part of the body and arms and low blood pressure in the legs. The defect is corrected surgically.

Back  -    New Search

Coats' disease (kohts) n.

a congenital anomaly of the blood vessels of the retina, which are abnormally dilated and leaking. This results in subretinal haemorrhage and massive exudation. [G. Coats (1876–1915), British ophthalmologist]

Back  -    New Search

cobalt (koh-bawlt) n.

a metallic element that forms part of the vitamin B_12 molecule. Symbol: Co. cobalt-60 (radiocobalt ) a powerful emitter of gamma radiation, used in the radiation treatment of cancer (see RADIOTHERAPY, TELECURIETHERAPY).

Back  -    New Search

cocaine (k-kayn) n.

an alkaloid, derived from the leaves of the coca plant (Erythroxylon coca) or prepared synthetically, sometimes used as a local anaesthetic in eye, ear, nose, and throat surgery. Since it may lead to psychological dependence, cocaine has largely been replaced by safer anaesthetics.

Back  -    New Search

cocainism (koh-kayn-izm) n.

1 the habitual use of, or addiction to, cocaine in order to experience its intoxicating effects.

2 the mental and physical deterioration resulting from addiction to cocaine.
Top

Back  -    New Search

coccus (kok-s) n. (pl. cocci)

any spherical bacterium. See GONOCOCCUS, MENINGOCOCCUS, MICROCOCCUS, PNEUMOCOCCUS, STAPHYLOCOCCUS, STREPTOCOCCUS.

Back  -    New Search

coccy- (coccyg-, coccygo-) prefix

denoting the coccyx.

Back  -    New Search

coccygodynia (coccydynia) (kok-si-goh-din-i) n.

pain in the coccyx and the neighbouring area.

Back  -    New Search

coccyx (kok-siks) n. (pl. coccyges or coccyxes)

the lowermost element of the backbone: the vestigial human tail. It consists of four rudimentary coccygeal vertebrae fused to form a triangular bone that articulates with the sacrum. See also VERTEBRA.
—coccygeal (kok-sij-il) adj.

Back  -    New Search

cochlea (kok-li) n.

the spiral organ of the labyrinth of the ear, which is concerned with the reception and analysis of sound.
—cochlear (kok-li-er) adj.

Back  -    New Search

cochlear duct (scala media) n.

see SCALA.

Back  -    New Search

cochlear implant n.

a device to improve the hearing of profoundly deaf people who derive no benefit from conventional hearing aids. It consists of an electrode that is permanently implanted into the inner ear (cochlea). An external battery-powered device with a microphone and an electronic processing unit passes information to the electrode using radio-frequency waves.

Back  -    New Search

cochlear nerve n.

the nerve connecting the cochlea to the brain and therefore responsible for the nerve impulses relating to hearing. It forms part of the vestibulocochlear nerve.

Back  -    New Search

Cockayne's syndrome (kok-aynz) n.

a hereditary disorder (inherited as an autosomal recessive condition) associated with trisomy of chromosome no. 20. Clinical features include epidermolysis bullosa, dwarfism, mental retardation, and pigmentary degeneration of the retina. [E. A. Cockayne (1880–1956), British physician]

Back  -    New Search

codeine (koh-deen) n.

an analgesic derived from morphine but less potent as a pain killer and sedative and less toxic. It is administered by mouth or injection to relieve pain and also to suppress coughs.

Back  -    New Search

Code of Professional Conduct for the Nurse, Midwife, and Health Visitor

Each registered nurse, midwife and health visitor shall act, at all times, in such a manner as to:
• safeguard and promote the interests of individual patients and clients;
• serve the interests of society;
•justify public trust and confidence and
• uphold and enhance the good standing and reputation of the professions.

As a registered nurse, midwife or health visitor, you are personally accountable for your practice and, in the excercise of your professional accountability, must:
1 act always in such a manner as to promote and safeguard the interests and well-being of patients and clients;
2 ensure that no action or omission on your part, or within your sphere of responsibility, is detrimental to the interests, condition or safety of patients and clients;
3 maintain and improve your professional knowledge and competence;
4 acknowledge any limitations in your knowledge and competence and decline any duties or responsibilities unless able to perform them in a safe and skilled manner;
5 work in an open and co-operative manner with patients, clients and their families, foster their independence and recognise and respect their involvement in the planning and delivery of care;
6 work in a collaborative and co-operative manner with health care professionals and others involved in providing care, and recognise and respect their particular contributions within the care team;
7 recognise and respect the uniqueness and dignity of each patient and client, and respond to their need for care, irrespective of their ethnic origin, religious beliefs, personal attributes, the nature of their health problems or any other factor;
8 report to an appropriate person or authority, at the earliest possible time, any conscientious objection which may be relevant to your professional practice;
9 avoid any abuse of your privileged relationship with patients and clients and of the privileged access allowed to their person, property, residence or workplace;
10 protect all confidential information concerning patients and clients obtained in the course of professional practice and make disclosures only with consent, where required by the order of a court or where you can justify disclosure in the wider public interest;
11 report to an appropriate person or authority, having regard to the physical, psychological and social effects on patients and clients, any circumstances in the environment of care which could jeopardise standards of practice;
12 report to an appropriate person or authority any circumstances in which safe and appropriate care for patients and clients cannot be provided;
13 report to an appropriate person or authority where it appears that the health or safety of colleagues is at risk, as such circumstances may compromise standards of practice and care;
14 assist professional colleagues, in the context of your own knowledge, experience and sphere of responsibility, to develop their professional competence, and assist others in the care team, including informal carers, to contribute safely and to a degree appropriate to their roles;
15 refuse any gift, favour or hospitality from patients or clients currently in your care which might be interpreted as seeking to exert influence to obtain preferential consideration and
16 ensure that your registration status is not used in the promotion of commercial products or services, declare any financial or other interests in relevant organisations providing such goods or services and ensure that your professional judgement is not influenced by any commerical considerations.

The scope of professional practice
The Code of Professional Conduct provides a firm bedrock upon which decisions about the scope of professional practice can be made. Practice must remain dynamic, sensitive, relevant and responsive to the changing needs of patients and clients and so must education for practice. The registered nurse, midwife or health visitor:
–must be satisfied that each aspect of practice is directed to meeting the needs and serving the interests of the patient or client;
–must endeavour always to achieve, maintain and develop knowledge, skill and competence to respond to those needs and interests;
–must honestly acknowledge any limits of personal knowledge and skill and take steps to remedy any relevant deficits effectively and appropriately in order to meet the needs of patients and clients;
–must ensure that any enlargement or adjustment of the scope of personal professional practice must be achieved without compromising or fragmenting existing aspects of professional practice and care and that the requirements of the Council's Code of Professional Conduct are satisfied throughout the whole area of practice;
–must recognise and honour the direct or indirect personal accountability born for all aspects of professional practice and
–must, in serving the interests of patients and clients and the wider interests of society, avoid any inappropriate delegation to others which compromises those interests.

Back  -    New Search

cod liver oil (kod) n.

a pale yellow oil, extracted from the livers of cod and related fish, that is rich in vitamins A and D and used in the treatment and prevention of deficiencies of these vitamins (e.g. rickets).

Back  -    New Search

-coele suffix

denoting 1 a body cavity.

2 see -CELE.
Top

Back  -    New Search

coeli- (coelio-) prefix

denoting the abdomen or belly.

Back  -    New Search

coeliac (seel-i-ak) adj.

of or relating to the abdominal region. c. trunk a branch of the abdominal aorta supplying the stomach, spleen, liver, and gall bladder.

Back  -    New Search

coeliac disease n.

a condition in which the small intestine fails to digest and absorb food. It is due to a permanent sensitivity of the intestinal lining to the protein gliadin, which is contained in gluten in the germ of wheat and rye and causes atrophy of the digestive and absorptive cells of the intestine. Symptoms include stunted growth, distended abdomen, and pale frothy foul-smelling stools. Medical name: gluten enteropathy .

Back  -    New Search

coelioscopy (see-li-os-kpi) n.

the technique of introducing an endoscope through an incision in the abdominal wall to examine the intestines and other organs within the abdominal cavity.

Back  -    New Search

coenzyme (koh-en-zym) n.

a nonprotein organic compound that, in the presence of an enzyme, plays an essential role in the reaction that is catalysed by the enzyme.

Back  -    New Search

coffee-ground vomit (kof-ee-grownd) n.

vomit containing gastric juices and small dark fragments of partly digested blood, indicating slow bleeding in the upper gastrointestinal tract.

Back  -    New Search

Cogan's syndrome (koh-gnz) n.

a disorder in which keratitis and iridocyclitis (see UVEITIS) are associated with tinnitus, vertigo, and bilateral sensorineural deafness. [D. G. Cogan (1908–93), US ophthalmologist]

Back  -    New Search

cognition (kog-nish-n) n.

a group of mental activities (including perception, recognition, and judgment) that leads to awareness of an object or situation. Compare CONATION.
—cognitive (kog-ni-tiv) adj.

Back  -    New Search

cognitive psychology n.

the school of psychology concerned with the ways in which knowledge is acquired, stored, correlated, and retrieved, by studying the mental processes underlying attention, concept formation, information processing, memory, and speech.

Back  -    New Search

cognitive therapy n.

a form of psychotherapy based on the belief that psychological problems are the products of faulty ways of thinking about the world. The therapist assists the patient to identify these false ways of thinking and to avoid them.

Back  -    New Search

coitus (sexual intercourse, copulation) (koh-it-s) n.

sexual contact between a man and a woman during which the erect penis enters the vagina and is moved within it by pelvic thrusts until ejaculation occurs. c. interruptus an unreliable contraceptive method in which the penis is removed from the vagina before ejaculation of semen. See also ORGASM.
—coital adj.

Back  -    New Search

col- (coli-, colo-) prefix

denoting the colon.

Back  -    New Search

colchicine (kol-chi-seen) n.

a drug obtained from the meadow saffron (Colchicum autumnale), administered by mouth to relieve pain in attacks of gout and to prevent attacks of polyserositis.

Back  -    New Search

cold (common cold) (kohld) n.

a widespread infectious virus disease causing inflammation of the mucous membranes of the nose, throat, and bronchial tubes. Symptoms include a sore throat, stuffy or runny nose, headache, cough, and general malaise.

Back  -    New Search

cold sore n.

see HERPES (SIMPLEX).

Back  -    New Search

colectomy (k-lek-tmi) n.

surgical removal of the colon (total c. ) or a segment of the colon (partial c. ). See also HEMICOLECTOMY, PROCTOCOLECTOMY.

Back  -    New Search

colestipol (k-les-ti-pol) n.

a drug administered by mouth to lower cholesterol levels in the blood in patients with primary hypercholesterolaemia. It binds bile acids, forming a complex that is excreted in the faeces. The reduction in bile acids causes cholesterol to be oxidized to bile acids, decreases low-density lipoprotein serum levels, and decreases serum cholesterol levels. Trade name: Colestid .

Back  -    New Search

colic (kol-ik) n.

severe abdominal pain, usually of fluctuating severity, with waves of pain seconds or a few minutes apart. infantile c. colic that is common among babies, due to wind in the intestine associated with feeding difficulties. intestinal c. colic due to partial or complete obstruction of the intestine or to constipation. Medical names: enteralgia , tormina . See also BILIARY (COLIC).

Back  -    New Search

coliform bacteria (kol-i-form) pl. n.

a group of Gram-negative rodlike bacteria that are normally found in the gastrointestinal tract and ferment the sugar lactose. It includes the genera Enterobacter, Escherichia, and Klebsiella.

Back  -    New Search

colistin (k-list-in) n.

an antibiotic administered by mouth to treat gastroenteritis and other bacterial infections. Trade name: Colomycin .

Back  -    New Search

colitis (k-ly-tis) n.

inflammation of the colon. The usual symptoms are diarrhoea, sometimes with blood and mucus, and lower abdominal pain. ischaemic c. colitis caused by partial or temporary cessation of blood supply to the colon. mucous c. see IRRITABLE BOWEL SYNDROME. ulcerative c. (idiopathic proctocolitis ) colitis of varying severity in which the rectum (see PROCTITIS) as well as a varying amount of the colon become inflamed and ulcerated; its cause is unknown.

Back  -    New Search

collagen (kol--jin) n.

a protein that is the principal constituent of white fibrous connective tissue (as occurs in tendons). Collagen is also found in skin, bone, cartilage, and ligaments.

Back  -    New Search

collagen disease n.

an obsolete term for connective-tissue disease.

Back  -    New Search

collar bone (kol-er) n.

see CLAVICLE.

Back  -    New Search

collateral (k-lat-er-l)

1 adj. accessory or secondary.

2 n. a branch (e.g. of a nerve fibre) that is at right angles to the main part.
Top

Back  -    New Search

collateral circulation n.

1 an alternative route provided for the blood by secondary vessels when a primary vessel becomes blocked.

2 the channels of communication between the blood vessels supplying the heart.
Top

Back  -    New Search

Colles' fracture (kol-iss) n.

see FRACTURE. [A. Colles (1773–1843), Irish surgeon]

Back  -    New Search

collodion (k-loh-din) n.

a syrupy solution of nitrocellulose in a mixture of alcohol and ether. When applied to minor wounds it evaporates to leave a thin clear transparent skin. Flexible collodion also contains camphor and castor oil, which allow the skin to stretch a little more.

Back  -    New Search

colloid (kol-oid) n.

a mixture in which particles of one component (diameter 10-6–10-4 mm) are dispersed in a continuous phase of another component.
—colloidal adj.

Back  -    New Search

collyrium (ko-leer-im) n.

a medicated solution used to bathe the eyes.

Back  -    New Search

coloboma (kol-boh-m) n. (pl. colobomata)

a defect in the development of the eye causing abnormalities ranging in severity from a notch in the lower part of the iris, making the pupil pear-shaped, to defects behind the iris in the fundus. The enlarged pupil causes dazzle symptoms.

Back  -    New Search

colon (koh-ln) n.

the main part of the large intestine, which consists of four sections – the ascending , transverse , descending , and sigmoid colons (see illustration). The colon absorbs large amounts of water and electrolytes from the undigested food passed on from the small intestine. At intervals strong peristaltic movements move the dehydrated contents (faeces) towards the rectum.

—colonic (koh-lon-ik) adj.

Back  -    New Search

colonic irrigation n.

washing out the contents of the large bowel by means of copious enemas, using either water, with or without soap, or other medication.

Back  -    New Search

colonoscopy (koh-ln-os-kpi) n.

a procedure for examining the interior of the entire colon and rectum using a flexible illuminated fibreoptic instrument (colonoscope ) introduced through the anus.

Back  -    New Search

colony (kol-ni) n.

a discrete population or mass of microorganisms, usually bacteria, all of which are considered to have developed from a single parent cell. See also CULTURE.

Back  -    New Search

colorimeter (kul--rim-it-er) n.

an instrument for determining the concentration of a particular compound in a preparation by comparing the intensity of colour in it with that in a standard preparation of known concentration.

Back  -    New Search

colostomy (k-lost-mi) n.

a surgical operation in which a part of the colon is brought through the abdominal wall and opened in order to drain or decompress the intestine. The colostomy may be temporary, eventually being closed to restore continuity; or permanent, usually when the rectum or lower colon has been removed.

Back  -    New Search

colostrum (k-los-trm) n.

the first secretion from the breast, occurring shortly after, or sometimes before, birth, prior to the secretion of true milk. It is a relatively clear fluid containing serum, white blood cells, and protective antibodies.

Back  -    New Search

colour blindness (kul-er) n.

any of various conditions in which certain colours are confused with one another. True lack of colour appreciation is extremely rare (see MONOCHROMAT); the most common type of colour blindness is red-blindness (see DALTONISM). See also DEUTERANOPIA, TRI-TANOPIA.

Back  -    New Search

colour flow ultrasound imaging n.

see DOPPLER ULTRASOUND.

Back  -    New Search

colp- (colpo-) prefix

denoting the vagina.

Back  -    New Search

colpitis (kol-py-tis) n.

inflammation of the vagina. See VAGINITIS.

Back  -    New Search

colpohysterectomy (kol-poh-hiss-ter-ek-tmi) n.

surgical removal of the uterus through the vagina. See HYSTERECTOMY.

Back  -    New Search

colpoperineorrhaphy (kol-poh-pe-ri-ni-o-rfi) n.

an operation to repair tears in the vagina and the muscles surrounding its opening, particularly posteriorly.

Back  -    New Search

colporrhaphy (kol-po-rfi) n.

an operation designed to remove lax and redundant vaginal tissue and so reduce the diameter of the vagina in cases of prolapse of the anterior vaginal wall (anterior c. ) or posterior vaginal wall (posterior c. ).

Back  -    New Search

colposcope (vaginoscope) (kol-poh-skohp) n.

an instrument that is inserted into the vagina and permits visual examination of the cervix and the upper part of the vagina (vaginal vault).
—colposcopy (kol-pos-kpi) n.

Back  -    New Search

colposuspension (kol-poh-su-spen-shn) n.

a surgical operation in which the upper part of the vaginal wall is fixed to the anterior abdominal wall by unabsorbable suture material. Performed through an abdominal incision, this sling operation is used in the surgical treatment of prolapse of the vaginal wall, particularly when stress incontinence exists. See also STAMEY PROCEDURE.

Back  -    New Search

colpotomy (kol-pot-mi) n.

an incision made into the wall of the vagina. This was formerly used to confirm the diagnosis of ectopic pregnancy, but has now been largely superseded by laparoscopy.

Back  -    New Search

column (kol-m) n.

(in anatomy) any pillar-shaped structure, especially any of the tracts of grey matter found in the spinal cord.

Back  -    New Search

coma (koh-m) n.

a state of unrousable unconsciousness.

Back  -    New Search

comatose (koh-m-tohs) adj.

in a state of coma; unconscious.

Back  -    New Search

combined therapy (km-bynd) n.

therapy that combines several types of treatment in order to improve results. It is usually a combination of surgery with radiotherapy and/or chemotherapy for the treatment of malignant tumours (see ADJUVANT THERAPY). See also SANDWICH THERAPY.

Back  -    New Search

comedo (kom-i-doh) n. (pl. comedones)

see BLACKHEAD.

Back  -    New Search

commando operation (k-mahn-doh) n.

a major operation performed to remove a malignant tumour from the head and neck. Extensive dissection, often involving the face, is followed by reconstruction to restore function and cosmetic acceptability.

Back  -    New Search

commensal (k-men-sl) n.

an organism that lives in close association with another of a different species without either harming or benefiting it. Compare SYMBIOSIS.
—commensalism n.

Back  -    New Search

comminuted fracture (kom-i-new-tid) n.

see FRACTURE.

Back  -    New Search

commissure (kom-iss-yoor) n.

1 a bundle of nerve fibres that crosses the midline of the central nervous system, often connecting similar structures on each side.

2 any other tissue connecting two similar structures.
Top

Back  -    New Search

commotio retinae (k-moh-shi-oh ret-i-nee) n.

swelling of the retina associated with sudden loss of vision, usually resulting from blunt trauma to the eye.

Back  -    New Search

communicable disease (contagious disease, infectious disease) (k-mew-nik-bl) n.

any disease that can be transmitted from one person to another. This may occur by direct physical contact, by common handling of a contaminated object (see FOMES), through a disease carrier, or by spread of infected droplets exhaled into the air.

Back  -    New Search

community health (k-mew-niti) n.

preventive services, mainly outside the hospital, involving the surveillance of special groups of the population, such as preschool and school children, women, and the elderly, by means of routine clinical assessment and screening tests. See also CHILD HEALTH CLINIC.

Back  -    New Search

Community Health Council (CHC) n.

(in Britain) a group of local residents appointed to voice the views of patients in relation to the National Health Service.

Back  -    New Search

community hospital n.

see HOSPITAL.

Back  -    New Search

community medicine n.

see PUBLIC HEALTH MEDICINE.

Back  -    New Search

community midwife (domiciliary midwife) n.

(in Britain) a registered nurse with special training in midwifery (both hospital and domiciliary practice). The midwife must be registered with the UKCC in order to practise; this requires regular refresher courses to supplement the basic qualification of Registered Midwife (RM). Community midwives are attached to hospital obstetric units and their work includes home deliveries and antenatal and postnatal care in the community.

Back  -    New Search

community nurses pl. n.

(in Britain) a generic term for health visitors, community midwives, and district nurses. See also DOMICILIARY SERVICES.

Back  -    New Search

community paediatrician n.

a consultant in paediatrics with special responsibility for the care of children outside the hospital. See also COMMUNITY HEALTH.

Back  -    New Search

community physician n.

see PUBLIC HEALTH PHYSICIAN.

Back  -    New Search

community services pl. n.

health and social services, including domiciliary services, that are available in the community but are distinguished from hospital-based services.

Back  -    New Search

community trust n.

an NHS trust that is concerned with the provision of community health services and, in some locations, mental health services.

Back  -    New Search

compartment (km-part-mnt) n.

any one of the spaces in a limb that are bounded by bone and thick sheets of fascia and contain the muscles and other tissues of the limb. c. syndrome swelling of the muscles in a compartment, which raises the pressure within so that the blood supply to the muscle is cut off, causing ischaemia and further swelling. It is caused by trauma, damage to blood vessels, or tight casts or bandages. See also VOLKMANN'S CONTRACTURE.

Back  -    New Search

compatibility (km-pati-bil-iti) n.

the degree to which the body's defence systems will tolerate the presence of intruding foreign material, such as blood when transfused or a kidney when transplanted. Compare INCOMPATIBILITY. See also HISTOCOMPATIBILITY, IMMUNITY.
—compatible adj.

Back  -    New Search

compensation (kom-pen-say-shn) n.

1 the act of making up for a functional or structural deficiency. For example, compensation for the loss of a diseased kidney is brought about by an increase in size of the remaining kidney, so restoring the urine-producing capacity.

2 (in psychoanalysis) the act of exaggerating an approved character trait to make up for a weakness in an opposite trait.
Top

Back  -    New Search

complement (kom-pli-mnt) n.

a substance in the blood, consisting of a group of nine different fractions, that aids the body's defences when antibodies combine with invading antigens. See also IMMUNITY.

Back  -    New Search

complementary medicine (kom-pli-ment-ri) n.

see ALTERNATIVE MEDICINE.

Back  -    New Search

complement fixation n.

the binding of complement to the complex that is formed when an antibody reacts with a specific antigen. Because complement is taken up from the serum only when such a reaction has occurred, testing for the presence of complement after mixing a suspension of a known organism with a patient's serum can give confirmation of infection with a suspected organism.

Back  -    New Search

complex (kom-pleks) n.

(in psychoanalysis) an emotionally charged and repressed group of ideas and beliefs that is capable of influencing an individual's behaviour.

Back  -    New Search

complication (kom-pli-kay-shn) n.

a disease or condition arising during the course of or as a consequence of another disease.

Back  -    New Search

compos mentis (kom-ps men-tis) adj.

of sound mind; sane.

Back  -    New Search

compress (kom-press) n.

a pad of material soaked in hot or cold water and applied to an injured part of the body to relieve the pain of inflammation.

Back  -    New Search

compressed air illness (caisson disease) (km-prest) n.

a syndrome occurring in people working under high pressure in diving bells or at great depths with breathing apparatus. On return to normal atmospheric pressure nitrogen dissolved in the bloodstream expands to form bubbles, causing pain (the bends ) and blocking the circulation in small blood vessels in the brain and elsewhere (decompression sickness ). Symptoms may be eliminated by returning the victim to a higher atmospheric pressure and reducing this gradually.

Back  -    New Search

compression (km-presh-n) n.

the state in which an organ, tissue, or part is subject to pressure. cerebral c. pressure on brain tissue from a cerebral tumour, intracranial haematoma, etc.

Back  -    New Search

compulsion (km-pul-shn) n.

an obsession that takes the form of a motor act, such as repetitive washing based on a fear of contamination.

Back  -    New Search

compulsory admission (km-pul-ser-i) n.

(in Britain) the entry and detention of a person within an institution without his consent, either because of mental illness (see MENTAL HEALTH ACT) or severe social deprivation and self-neglect (see SECTION 47). Compare VOLUNTARY ADMISSION.

Back  -    New Search

computerized tomography (CT) (km-pew-t-ryzd) n.

a specialized form of X-ray examination in which the X-ray source and detector (CT scanner) rotate around the object to be scanned and the information can be used to produce crosssectional images by computer (a CT scan ). A higher radiation dose is received by the patient than with conventional X-rays, but the diagnostic information obtained outweighs the risk. CT scanning is particularly useful in the head, chest, and abdomen.

Back  -    New Search

conation (koh-nay-shn) n.

the group of mental activities (including drives, will, and instincts) that leads to purposeful action. Compare COGNITION.

Back  -    New Search

conception (kn-sep-shn) n.

1 (in gynaecology) the start of pregnancy, when a male germ cell (sperm) fertilizes a female germ cell (ovum) in the Fallopian tube.

2 (in psychology) an idea or mental impression.
Top

Back  -    New Search

conceptus (kn-sep-ts) n.

the products of conception: the developing fetus and its enclosing membrane at all stages in the uterus.

Back  -    New Search

concha (konk-) n. (pl. conchae)

(in anatomy) any part resembling a shell. c. auriculae a depression on the outer surface of the pinna (auricle), which leads to the external auditory meatus of the outer ear. See also NASAL (CONCHA).

Back  -    New Search

concordance (kn-kor-dnss) n.

similarity of any physical characteristic that is found in both of a pair of twins.

Back  -    New Search

concretion (kn-kree-shn) n.

a stony mass formed within such an organ as the kidney, especially the coating of an internal organ or a foreign body with calcium salts. See also CALCULUS.

Back  -    New Search

concussion (kn-kush-n) n.

a condition caused by injury to the head, characterized by headache, confusion, and amnesia. These symptoms may be prolonged and constitute a post-concussional syndrome . See also (CEREBRAL) CONTUSION, PUNCH-DRUNK SYNDROME.

Back  -    New Search

condenser (kn-den-ser) n.

(in microscopy) an arrangement of lenses beneath the stage of a microscope. It can be adjusted to provide correct focusing of light on the microscope slide.

Back  -    New Search

conditioned reflex (kn-dish-nd) n.

a reflex in which the response occurs not to the sensory stimulus that normally causes it but to a separate stimulus, which has been learnt to be associated with it.

Back  -    New Search

conditioning (kn-dish-n-ing) n.

the establishment of new behaviour by modifying the stimulus/response associations.

Back  -    New Search

condom (kon-dm) n.

a sheath made of latex rubber, plastic, or silk that is fitted over the penis during sexual intercourse. A condom is a reasonably reliable contraceptive; it also protects both partners against sexually transmitted diseases (including AIDS). female c. a similar device for women, designed to fit into the vagina.

Back  -    New Search

conduct disorder (kon-dukt) n.

a repetitive and persistent pattern of aggressive or otherwise antisocial behaviour. It is usually recognized in childhood or adolescence and can lead to a dyssocial or impulsive personality disorder. Treatment is usually with behaviour therapy or family therapy.

Back  -    New Search

conduction (kn-duk-shn) n.

1 (in physics) the process in which heat is transferred through a substance from regions of higher to regions of lower temperature.

2 (in physiology) the passage of a nerve impulse.
Top

Back  -    New Search

conductor (kn-duk-ter) n.

1 (in physics) a substance capable of transmitting heat (e.g. copper, silver) or electricity.

2 (in surgery) a grooved surgical director.
Top

Back  -    New Search

condyle (kon-dil) n.

a rounded protuberance that occurs at the ends of some bones, e.g. the occipital bone, and forms an articulation with another bone.

Back  -    New Search

condyloma (kon-di-loh-m) n. (pl. condylomata)

a raised wartlike growth. c. acuminatum (pl. condylomata acuminata) a wart, caused by human papillomavirus, found on the vulva, under the foreskin, or on the skin of the anal region. c. latum (pl. condylomata lata) a flat plaque occurring in the anogenital region in the secondary stage of syphilis.

Back  -    New Search

cone (kohn) n.

one of the two types of light-sensitive cells in the retina of the eye (compare ROD). Cones are essential for acute vision and can also distinguish colours.

Back  -    New Search

cone biopsy n.

surgical removal, via a colposcope, of a cone-shaped segment of tissue from the cervix of the uterus. It may be performed if a cervical smear reveals evidence of CIN (see CERVICAL INTRAEPITHELIAL NEOPLASIA): the affected tissue is removed and examined microscopically for confirmation of the diagnosis.

Back  -    New Search

confabulation (kn-fab-yoo-lay-shn) n.

the invention of circumstantial but fictitious detail about events supposed to have occurred in the past. Usually this is to disguise a loss of memory; it typically occurs in Korsakoff's syndrome.

Back  -    New Search

confection (kn-fek-shn) n.

(in pharmacy) a sweet substance that is combined with a medicinal preparation to make it suitable for administration.

Back  -    New Search

conflict (kon-flikt) n.

(in psychology) the state produced when a stimulus produces two opposing reactions. Conflict has been used to explain the development of neurotic disorders, and the resolution of conflict remains an important part of psychoanalysis. See also CONVERSION.

Back  -    New Search

congenital (kn-jen-it'l) adj.

describing a condition that is recognized at birth or that is believed to have been present since birth. Congenital malformations include all disorders present at birth whether they are inherited or caused by an environmental factor.

Back  -    New Search

congenital dislocation of the hip (CDH) n.

an abnormality of the hip joint, present at birth, in which the head of the femur is displaced or easily displaceable from the acetabulum, which is poorly developed. It frequently affects both hip joints. See also BARLOW'S SIGN, ORTOLANI MANOEUVRE.

Back  -    New Search

congenital heart disease n.

see BLUE BABY.

Back  -    New Search

congestion (kn-jes-chn) n.

an accumulation of blood within an organ, which is the result of back pressure within its veins (for example congestion of the lungs and liver occurs in heart failure).

Back  -    New Search

Congo red (kon-goh) n.

a dark-red or reddish-brown pigment that becomes blue in acidic conditions. It is used as a histological stain.

Back  -    New Search

coning (kohn-ing) n.

prolapse of the brainstem through the foramen magnum of the skull as a result of raised intracranial pressure: it is usually immediately fatal.

Back  -    New Search

conization (ko-ny-zay-shn) n.

surgical removal of a cone of tissue. The technique is commonly used in excising a portion of the cervix (neck) of the uterus (see CONE BIOPSY) for the treatment of cervicitis or early cancer (carcinoma in situ).

Back  -    New Search

conjoined twins (kn-joind) pl. n.

see SIAMESE TWINS.

Back  -    New Search

conjugate (conjugate diameter, true conjugate) (kon-jg-it) n.

the distance between the front and rear of the pelvis measured from the most prominent part of the sacrum to the back of the pubic symphysis. It is estimated by subtracting 1.3–1.9 cm from the distance between the lower edge of the symphysis and the sacrum (the diagonal c. ). If the true conjugate is less than about 10.2 cm, delivery of an infant through the natural passages may be difficult or impossible.

Back  -    New Search

conjunctiva (kon-junk-ty-v) n.

the delicate mucous membrane that covers the front of the eye and lines the inside of the eyelids.
—conjunctival adj.

Back  -    New Search

conjunctivitis (pink eye) (kn-junk-ti-vy-tis) n.

inflammation of the conjunctiva, which becomes red and swollen and produces a watery or pus-containing discharge. Conjunctivitis is caused by infection by bacteria or viruses, allergy, or physical or chemical irritation. allergic (or vernal ) c. conjunctivitis of allergic origin, often associated with hay fever or other forms of atopy. inclusion c. a sexually transmitted form of conjunctivitis caused by Chlamydia trachomatis. It can be acquired by newborn infants as they pass through an infected birth canal. See also TRACHOMA, OPHTHALMIA (NEONATORUM).

Back  -    New Search

connective tissue (k-nek-tiv) n.

the tissue that supports, binds, or separates more specialized tissues and organs or functions as a packing tissue of the body. It consists of an amorphous matrix of mucopolysaccharides (ground substance ) in which may be embedded white (collagenous), yellow (elastic), and reticular fibres, fat cells, fibroblasts, mast cells, and macrophages. Forms of connective tissue include bone, cartilage, tendons, ligaments, and adipose, areolar, and elastic tissues.

Back  -    New Search

connective-tissue disease n.

any one of a group of diseases that are characterized by inflammatory changes in connective tissue. They include dermatomyositis, systemic and discoid lupus erythematosus, morphoea, polyarteritis nodosa, and rheumatoid arthritis.

Back  -    New Search

Conn's syndrome (konz) n.

a condition resulting from overproduction of the hormone aldosterone due to disease of the adrenal cortex. See ALDOSTERONISM. [W. J. Conn (1907– ), US physician]

Back  -    New Search

consanguinity (kon-sang-win-iti) n.

relationship by blood; the sharing of a common ancestor within a few generations.

Back  -    New Search

consensus management (kn-sen-ss) n.

a style of management practised in the National Health Service, in which multidisciplinary management teams make decisions based on discussion and mutual agreement.

Back  -    New Search

consequentialism (kon-si-kwen-shl-izm) n.

an ethical approach that stresses the importance of taking account of the objective effects or consequences of one's actions on other people and on the overall situation.

Back  -    New Search

conservative treatment (kn-ser-v-tiv) n.

treatment aimed at preventing a condition from becoming worse, in the expectation that either natural healing will occur or progress of the disease will be so slow that no drastic treatment will be justified. Compare RADICAL TREATMENT.

Back  -    New Search

consolidation (kn-soli-day-shn) n.

1 the state of the lung in which the alveoli (air sacs) are filled with fluid produced by inflamed tissue, as in pneumonia.

2 the stage of repair of a broken bone following callus formation, during which the callus is transformed by osteoblasts into mature bone.
Top

Back  -    New Search

constipation (kon-sti-pay-shn) n.

a condition in which bowel evacuations occur infrequently, or in which the faeces are hard and small, or where passage of faeces causes difficulty or pain. Recurrent or longstanding constipation is treated by increasing dietary fibre (roughage), laxatives, or enemas.

Back  -    New Search

constrictor (kn-strik-ter) n.

any muscle that compresses an organ or causes a hollow organ or part to contract.

Back  -    New Search

consultant (kn-sul-t'nt) n.

a fully trained specialist in a branch of medicine who accepts total responsibility for patient care.

Back  -    New Search

consumption (kn-sump-shn) n.

any disease causing wasting of tissues, especially (formerly) pulmonary tuberculosis.
—consumptive adj.

Back  -    New Search

contact (kon-takt) n.

transmission of an infectious disease by touching or handling an infected person or animal (direct c. ) or by inhaling airborne droplets, etc., containing the infective microorganism (indirect c. ).

Back  -    New Search

contact lenses pl. n.

glass or plastic lenses worn directly against the eye, separated from it only by a film of tear fluid. Contact lenses are used mainly in place of glasses to correct errors of refraction, but they may be used for protection in some types of corneal disease.

Back  -    New Search

contagious disease (kn-tay-js) n.

originally, a disease transmitted only by direct physical contact: now usually taken to mean any communicable disease.

Back  -    New Search

continent diversion (kon-ti-nnt dy-ver-shn) n.

the diversion and collection of urine, usually after cystectomy, by constructing a reservoir or pouch from a section of small or large intestine or a combination of both. This can be emptied by catheterization via a small stoma; a urinary drainage bag is not required.

Back  -    New Search

contra-prefix

denoting against or opposite.

Back  -    New Search

contraception (kon-tr-sep-shn) n.

the prevention of unwanted pregnancy (see COITUS (INTERRUPTUS), CONDOM, DIAPHRAGM, IUCD, ORAL CONTRACEPTIVE, POSTCOITAL (CONTRACEPTION), RHYTHM METHOD, STERILIZATION). Recently developed methods include two- or three-monthly injections of a progestogen, hormonal skin patches, subcutaneous implants of progestogen, hormonal intrauterine devices (see IUS), and vaginal rings containing progestogen.
—contraceptive adj., n.

Back  -    New Search

contraction (kn-trak-shn) n.

the shortening of a muscle in response to a motor nerve impulse. This generates tension in the muscle, usually causing movement.

Back  -    New Search

contracture (kn-trak-cher) n.

fibrosis of muscle or connective tissue producing shortening and resulting in deformity of a joint. See also DUPUYTREN'S CONTRACTURE, VOLKMANN'S CONTRACTURE.

Back  -    New Search

contraindication (kon-tr-in-di-kay-shn) n.

any factor in a patient's condition that makes it unwise to pursue a certain line of treatment.

Back  -    New Search

contralateral (kon-tr-lat-er-l) adj.

on or affecting the opposite side of the body.

Back  -    New Search

contrast medium (kon-trahst) n.

any substance, such as barium sulphate, that is used to improve visibility of structures during radiography. See also RADIOPAQUE.

Back  -    New Search

contrecoup (kon-tr-koo) n.

injury of a part resulting from a blow on its opposite side. This may happen, for example, if a blow on the back of the head causes the front of the brain to be pushed against the inner surface of the skull.

Back  -    New Search

controlled drug (kn-trohld) n.

see MISUSE OF DRUGS ACT 1971.

Back  -    New Search

contusion (kn-tew-zhn) n.

see BRUISE. cerebral c. bruising of the brain, resulting from head injury or surgery. Clinical signs range from concussion to coma, reflecting the severity of the trauma.

Back  -    New Search

convection (kn-vek-shn) n.

the transfer of heat through a liquid or gas by movement of the heated portions of the liquid or gas.

Back  -    New Search

conversion (kn-ver-shn) n.

(in psychiatry) the expression of conflict as physical symptoms.

Back  -    New Search

conversion disorder n.

a psychological disorder, formerly known as conversion hysteria , in which a conflict or need manifests itself as an organic dysfunction or a physical symptom, such as blindness, deafness, loss of sensation, gait abnormalities, or paralysis of various parts of the body. None of these can be accounted for by organic disease.

Back  -    New Search

convolution (kon-v-loo-shn) n.

a folding or twisting, such as one of the many that cause the fissures, sulci, and gyri of the surface of the cerebrum.

Back  -    New Search

convulsion (kn-vul-shn) n.

an involuntary contraction of the muscles producing contortion of the body and limbs. Rhythmic convulsions of the limbs are a feature of major epilepsy. febrile c. an epileptic-type seizure associated with a fever, which affects infants and young children and is usually caused by a viral infection.

Back  -    New Search

Cooley's anaemia (koo-liz) n.

see THALASSAEMIA. [T. B. Cooley (1871–1945), US paediatrician]

Back  -    New Search

Coombs' test (koomz) n.

a means of detecting rhesus antibodies on the surface of red blood cells that precipitate proteins (globulins) in the blood serum. The test is used in the diagnosis of haemolytic anaemia. [R. R. A. Coombs (1921– ), British immunologist]

Back  -    New Search

copper sulphate (kop-er) n.

a salt of copper that, in solution, has been used as a fungicide and is a constituent of Fehling's and Benedict's solutions, used to test for the presence of glucose in the urine. Formula:
CuSO_4
.

Back  -    New Search

copr- (copro-) prefix

denoting faeces.

Back  -    New Search

coprolalia (kop-r-lay-li) n.

the repetitive speaking of obscene words. It can be involuntary, as part of the Gilles de la Tourette syndrome.

Back  -    New Search

coprolith (kop-r-lith) n.

a mass of hard faeces within the colon or rectum, due to chronic constipation. It may become calcified.

Back  -    New Search

coproporphyrin (kop-r-por-fi-rin) n.

a porphyrin compound that is formed during the synthesis of protoporphyrin IX. Coproporphyrin is excreted in the faeces in hereditary coproporphyria .

Back  -    New Search

co-proxamol (koh-proks--mol) n.

an analgesic drug consisting of a combination of the drug paracetamol and the weakly narcotic drug dextropropoxyphene. It is administered by mouth. Trade names: Distalgesic , Paxalgesic .

Back  -    New Search

copulation (kop-yoo-lay-shn) n.

see COITUS.

Back  -    New Search

cor (kor) n.

the heart. c. pulmonale enlargement of the right ventricle of the heart resulting from disease of the lungs or pulmonary arteries.

Back  -    New Search

coracoid process (ko-r-koid) n.

a beaklike process that curves upwards and forwards from the top of the scapula, over the shoulder joint.

Back  -    New Search

cord (kord) n.

any long flexible structure, which may be solid or tubular. Examples include the spermatic cord, spinal cord, umbilical cord, and vocal cord.

Back  -    New Search

cordectomy (kor-dek-tmi) n.

surgical removal of a vocal cord or, more usually, a piece of the vocal cord (partial c. ).

Back  -    New Search

cordocentesis (kor-doh-sen-tee-sis) n.

the removal of a sample of fetal blood by inserting a hollow needle through the abdominal wall of a pregnant woman, under ultrasound guidance, into the umbilical vein. The blood is subjected to chromosome analysis and biochemical and other tests to determine the presence of abnormalities. See also PRENATAL DIAGNOSIS.

Back  -    New Search

cordotomy (chordotomy) (kor-dot-mi) n.

a surgical procedure for the relief of severe and persistent pain in the pelvis or lower limbs, in which the tracts of the spinal cord transmitting the sensation of pain to consciousness are severed in the cervical (neck) region.

Back  -    New Search

corium (kor-im) n.

see DERMIS.

Back  -    New Search

corn (korn) n.

an area of hard thickened skin on or between the toes: a type of callosity produced by ill-fitting shoes. Medical name: clavus .

Back  -    New Search

cornea (korn-i) n.

the transparent circular part of the front of the eyeball. It refracts the light entering the eye onto the lens, which then focuses it onto the retina.
—corneal (korn-il) adj.

Back  -    New Search

corneal graft n.

see KERATOPLASTY.

Back  -    New Search

cornification (kor-ni-fi-kay-shn) n.

see KERATINIZATION.

Back  -    New Search

cornu (kor-new) n. (pl. cornua)

(in anatomy) a horn-shaped structure. See also HORN.

Back  -    New Search

corona (k-roh-n) n.

a crown or crown-like structure. c. capitis the crown of the head.

Back  -    New Search

coronal (ko-r-nl) adj.

relating to the crown of the head or of a tooth. c. plane the plane that divides the body into dorsal and ventral parts. c. suture the immovable joint between the frontal and parietal bones (see SKULL).

Back  -    New Search

coronary arteries (ko-rn-er-i) pl. n.

the arteries supplying blood to the heart. They arise from the aorta, just above the aortic valve, and form branches that encircle the heart.

Back  -    New Search

coronary bypass graft n.

an operation in which a segment of a coronary artery narrowed by atheroma is bypassed by an autologous section of healthy saphenous vein or internal mammary artery at thoracotomy. The improved blood flow resulting from one or more such grafts relieves angina pectoris and reduces the risk of myocardial infarction.

Back  -    New Search

coronary care n.

a type of intensive care developed in order to provide for the needs of critically ill and immediately postoperative patients with coronary artery disease in a c. c. unit . see INTENSIVE CARE.

Back  -    New Search

coronary thrombosis n.

the formation of a blood clot (thrombus) in the coronary artery, which obstructs the flow of blood to the heart. See MYOCARDIAL INFARCTION.

Back  -    New Search

coroner (ko-rn-er) n.

the official who presides at an inquest. He must be either a medical practitioner or a lawyer of at least five years standing.

Back  -    New Search

coronoid process (ko-rn-oid) n.

1 a process on the upper end of the ulna. It forms part of the notch that articulates with the humerus.

2 the process on the ramus of the mandible to which the temporalis muscle is attached.
Top

Back  -    New Search

corpus (kor-ps) n. (pl. corpora)

any mass of tissue that can be distinguished from its surroundings. c. callosum the broad band of nervous tissue that connects the two cerebral hemispheres. c. cavernosum either of a pair of cylindrical blood sinuses that form the erectile tissue of the penis and clitoris. c. luteum the glandular tissue in the ovary that forms at the site of a ruptured Graafian follicle after ovulation. It secretes the hormone progesterone, which prepares the uterus for implantation. If implantation fails the corpus luteum degenerates. If an embryo becomes implanted the corpus luteum continues to secrete progesterone until the fourth month of pregnancy. c. spongiosum the blood sinus that surrounds the urethra of the male. Together with the corpora cavernosa, it forms the erectile tissue of the penis. c. striatum the part of the basal ganglia in the cerebral hemispheres of the brain consisting of the caudate nucleus and the lentiform nucleus.

Back  -    New Search

corpuscle (kor-ps-l) n.

any small particle, cell, or mass of tissue.

Back  -    New Search

corrective (k-rek-tiv) n.

any drug or agent that modifies the action of another substance.

Back  -    New Search

Corrigan's pulse (water-hammer pulse) (ko-ri-gnz) n.

a pulse characterized by an initial surge followed by a sudden collapse, usually due to aortic regurgitation. [Sir D. J. Corrigan (1802–80), Irish physician]

Back  -    New Search

cortex (kor-teks) n. (pl. cortices)

the outer part of an organ, situated immediately beneath its capsule or outer membrane.
—cortical (kor-ti-kl) adj.

Back  -    New Search

corticosteroid (corticoid) (kor-ti-koh-steer-oid) n.

any steroid hormone synthesized by the adrenal cortex. See GLUCOCORTICOID, MINERALOCORTICOID.

Back  -    New Search

corticotrophin (kor-ti-koh-troh-fin) n.

see ACTH.

Back  -    New Search

cortisol (kor-ti-sol) n.

a steroid hormone: the major glucocorticoid synthesized and released by the human adrenal cortex. It is important for normal carbohydrate metabolism and for the normal response to any stress. See also HYDROCORTISONE.

Back  -    New Search

cortisone (kor-tiz-ohn) n.

a naturally occurring corticosteroid that is used mainly to treat deficiency of corticosteroid hormones in Addison's disease and following surgical removal of the adrenal glands. It is administered by mouth or injection and may cause serious side-effects such as stomach ulcers, muscle and bone damage, and eye changes.

Back  -    New Search

Corynebacterium (k-ry-ni-bak-teer-im) n.

a genus of Gram-positive, mostly aerobic, nonmotile rodlike bacteria. C. diphtheriae (Klebs-Loeffler bacillus) the causative organism of diphtheria. It occurs in one of three forms: gravis , intermedius , and mitis .

Back  -    New Search

coryza (cold in the head) (k-ry-z) n.

a catarrhal inflammation of the mucous membrane in the nose caused by either a cold or hay fever. See also CATARRH.

Back  -    New Search

cost- (costo-) prefix

denoting the rib(s).

Back  -    New Search

costal (kos-t'l) adj.

of or relating to the ribs. c. cartilage a cartilage that connects a rib to the breastbone (sternum).

Back  -    New Search

costive (kost-iv) adj.

constipated.

Back  -    New Search

cot death (sudden infant death syndrome, SIDS) (kot) n.

the sudden unexpected death of an infant less than two years old (peak occurrence between two and six months) from an unidentifiable cause. There appear to be many factors involved, the most important of which is the position in which the baby is laid to sleep: babies who sleep on their fronts (the prone position) have an increased risk.

Back  -    New Search

co-trimoxazole (koh-tri-moks--zohl) n.

an antibacterial drug consisting of sulphamethoxazole and trimethoprim. Co-trimoxazole is taken by mouth and is particularly useful for treating urinarytract, respiratory-tract, and gastrointestinal infections. Side-effects may be severe. Trade names: Bactrim , Septrin .

Back  -    New Search

cotyledon (kot-i-lee-dn) n.

any of the major convex subdivisions of the mature placenta. Each cotyledon contains a major branch of the umbilical blood vessels.

Back  -    New Search

cotyloid cavity (kot-i-loid) n.

see ACETABULUM.

Back  -    New Search

coughing (kof-ing) n.

a form of violent exhalation by which irritant particles in the airways can be expelled. Medical name: tussis .

Back  -    New Search

coulomb (koo-lom) n.

the SI unit of electric charge, equal to the quantity of electricity transferred by 1 ampere in 1 second. Symbol: C.

Back  -    New Search

coumarin (koo-m-rin) n.

a drug used to prevent coagulation in the treatment of thrombophlebitis and pulmonary embolism.

Back  -    New Search

counselling (kown-sl-ing) n.

a method of approaching psychological difficulties in adjustment that aims to help the client work out his own problems.

Back  -    New Search

counterextension (kownt-er-eks-ten-shn) n.

traction on one part of a limb, while the remainder of the limb is held steady: used particularly in the treatment of a fractured femur.

Back  -    New Search

counterirritant (kownt-er-i-ri-t'nt) n.

an agent, such as methyl salicylate, that causes irritation when applied to the skin and is used in order to relieve more deep-seated pain or discomfort.—counterirritation n.

Back  -    New Search

countertraction (kownt-er-trak-shn) n.

the use of an opposing force to balance that being applied during traction, when a strong continuous pull is applied to a limb so that broken bones can be kept in alignment during healing.

Back  -    New Search

Cowper's glands (bulbourethral glands) (kow-perz) pl. n.

a pair of small glands that open into the urethra at the base of the penis. Their secretion contributes to the seminal fluid. [W. Cowper (1666–1709), English surgeon]

Back  -    New Search

cowpox (kow-poks) n.

a virus infection of cows' udders, transmitted to man by direct contact, causing very mild symptoms similar to smallpox. An attack confers immunity to smallpox. Medical name: vaccinia .

Back  -    New Search

cox- (coxo-) prefix

denoting the hip.

Back  -    New Search

coxa (koks-) n. (pl. coxae)

1 the hip bone.

2 the hip joint. c. valga a deformity of the hip joint in which the angle between the neck and shaft of the femur is abnormally increased. c. vara a deformity of the hip joint in which the angle between the neck and shaft of the femur is abnormally decreased.
Top

Back  -    New Search

coxalgia (koks-al-ji) n.

1 pain in the hip joint.

2 disease of the hip joint.
Top

Back  -    New Search

Coxsackie virus (kok-sak-i) n.

one of a group of RNA-containing viruses that are able to multiply in the gastrointestinal tract (see ENTEROVIRUS). Type A viruses generally cause less severe diseases, although some cause meningitis and severe throat infections. Type B viruses cause inflammation or degeneration of brain or heart tissue and they can also attack the muscles of the chest wall, the bronchi, pancreas, thyroid, and conjunctiva. See also BORNHOLM DISEASE, HAND, FOOT, AND MOUTH DISEASE.

Back  -    New Search

CPA n.

see CYPROTERONE.

Back  -    New Search

crab louse (krab) n.

see PHTHIRUS.

Back  -    New Search

cradle (kray-d'l) n.

a framework of metal strips or other material that forms a cage over an injured part of the body of a patient lying in bed, to protect it from the pressure of the bedclothes.

Back  -    New Search

cradle cap n.

a common condition in young babies in which crusty white or yellow scales form a ‘cap’ on the scalp. It is treated by applying oil or using a special shampoo and usually resolves in the first year of life, although it may represent the start of seborrhoeic eczema.

Back  -    New Search

cramp (kramp) n.

prolonged painful contraction of a muscle. It is sometimes caused by an imbalance of the salts in the body, but is more often a result of fatigue, imperfect posture, or stress. occupational c. spasm in the muscles making it impossible to perform a specific task but allowing the use of these muscles for any other movement.

Back  -    New Search

crani- (cranio-) prefix

denoting the skull.

Back  -    New Search

cranial nerves (kray-nil) pl. n.

the 12 pairs of nerves that arise directly from the brain and leave the skull through separate apertures. Compare SPINAL NERVES.

Back  -    New Search

craniometry (kray-ni-om-itri) n.

the science or practice of measuring the differences in the size and shape of skulls.

Back  -    New Search

craniopagus (dicephalus) (kray-ni-op-gs) n.

Siamese twins united by their heads.

Back  -    New Search

craniopharyngioma (kray-ni-oh-f-rinj-i-oh-m) n.

a brain tumour derived from remnants of Rathke's pouch , an embryologic structure from which the pituitary gland is partly formed.

Back  -    New Search

craniostenosis (kray-ni-oh-sti-noh-sis) n.

premature closing of the sutures between the cranial bones during development, resulting in the skull remaining abnormally small. Compare CRANIOSYNOSTOSIS.

Back  -    New Search

craniosynostosis (kray-ni-oh-sin-os-toh-sis) n.

premature fusion of some of the cranial sutures, usually before birth, so that the skull is unable to expand in certain directions to assume its normal shape under the influence of the growing brain. The skull may become elongated from front to back, broad and short, peaked (oxycephaly), or asymmetrical. Compare CRANIOSTENOSIS.

Back  -    New Search

craniotabes (kray-ni-oh-tay-beez) n.

abnormal thinness and brittleness of the bones of the vault of the skull, occurring in children with rickets.

Back  -    New Search

craniotomy (kray-ni-ot-mi) n.

1 surgical removal of a portion of the skull, performed to expose the brain and meninges for inspection or biopsy or to relieve excessive intracranial pressure (as in a subdural haematoma).

2 surgical perforation of the skull of a dead fetus during difficult labour, so that delivery may continue.
Top

Back  -    New Search

cranium (kray-nim) n.

the part of the skeleton that encloses the brain. It consists of eight bones connected together by immovable joints (see SKULL).
—cranial adj.

Back  -    New Search

creatine (kree--teen) n.

a product of protein metabolism found in muscle. c. phosphate (phosphocreatine , phosphagen ) the phosphate of creatine, which acts as a store of high-energy phosphate in muscle and serves to maintain adequate amounts of ATP.

Back  -    New Search

creatinine (kree-at-i-neen) n.

a substance derived from creatine and creatine phosphate in muscle. Creatinine is excreted in the urine.

Back  -    New Search

creatinuria (kree-at-in-yoor-i) n.

an excess of the nitrogenous compound creatine in the urine.

Back  -    New Search

creatorrhoea (kree-at--ree-) n.

the passage of excessive nitrogen in the faeces due to failure of digestion or absorption in the small intestine. It is found particularly in pancreatic failure. See CYSTIC FIBROSIS, PANCREATITIS.

Back  -    New Search

Credé's method (kray-dayz) n.

a technique for expelling the placenta from the uterus. With the uterus contracted, downward pressure is applied to the uterus through the abdominal wall in the direction of the birth canal. This method has now been largely replaced by the Brandt Andrews method. [K. S. F. Credé (1819–92), German gynaecologist]

Back  -    New Search

creeping eruption (larva migrans) (kreep-ing) n.

a skin disease caused either by larvae of nematode worms (e.g. Ancylostoma braziliense) or by the maggots of certain flies. The larvae burrow within the skin tissues, their movements marked by long thin red lines that cause the patient intense irritation.

Back  -    New Search

crepitation (rale) (krep-i-tay-shn) n.

a soft fine crackling sound heard in the lungs through the stethoscope. Crepitations are not normally heard in healthy lungs.

Back  -    New Search

crepitus (krep-its) n.

1 a crackling sound or grating feeling produced by bone rubbing on bone or roughened cartilage, detected on movement of an arthritic joint.

2 a similar sound heard with a stethoscope over an inflamed lung when the patient breathes in.
Top

Back  -    New Search

cresol (kree-sol) n.

a strong antiseptic effective against many microorganisms and used mostly in soap solutions as a general disinfectant. Cresol solutions irritate the skin and if taken by mouth are corrosive and cause pain, nausea, and vomiting.

Back  -    New Search

crest (krest) n.

a ridge or linear protuberance, particularly on a bone.

Back  -    New Search

CREST syndrome (krest) n.

a disease characterized by the association of calcinosis, Raynaud's phenomenon, (o)esophageal malfunction, sclerodactyly (tapering fingers), and telangiectasia. It represents a variant of systemic sclerosis and may be associated with severe pulmonary hypertension.

Back  -    New Search

cretinism (kret-in-izm) n.

a syndrome of dwarfism, mental retardation, and coarseness of the skin and facial features due to congenital hypothyroidism.

Back  -    New Search

Creutzfeldt-Jakob disease (CJD) (kroits-felt yak-ob) n.

a disease in which rapid progressive degeneration of brain tissue results in dementia and eventually death. It is thought to be caused by an abnormal prion protein (see SPONGIFORM ENCEPHALOPATHY). Most cases occur sporadically but some forms of CJD are inherited and a few are acquired. A new variant form of acquired CJD has been linked with the consumption of beef from cattle infected with bovine spongiform encephalopathy (BSE). [H. G. Creutzfeldt (1885–1964) and A. M. Jakob (1884–1931), German psychiatrists]

Back  -    New Search

cribriform plate (krib-ri-form) n.

see ETHMOID BONE.

Back  -    New Search

cricoid cartilage (kry-koid) n.

the cartilage, shaped like a signet ring, that forms part of the anterior and lateral walls and most of the posterior wall of the larynx.

Back  -    New Search

cri-du-chat syndrome (kree-doo-sha) n.

a congenital condition of severe mental retardation associated with an abnormal facial appearance, spasticity, and a characteristic catlike cry in infancy. It results from an abnormality in chromosome no. 5.

Back  -    New Search

Crigler-Najjar syndrome (kry-gler nah-jar) n.

a genetic disease in which the liver enzyme glucuronyl transferase, responsible for dealing with bilirubin, is absent. Large amounts of bilirubin accumulate in the blood, and the child becomes progressively more jaundiced. Life expectancy is usually less than two years. [J. F. Crigler (1919– ) and V. A. Najjar (1914– ), US paediatricians]

Back  -    New Search

crisis (kry-sis) n. (pl. crises)

1 the turning point of a disease, after which the patient either improves or deteriorates. Since the advent of antibiotics, infections seldom reach the point of crisis.

2 the occurrence of sudden severe pain in certain diseases. See also DIETL'S CRISIS.
Top

Back  -    New Search

crista (krist-) n. (pl. cristae)

1 the sensory structure within the ampulla of a semicircular canal within the inner ear.

2 one of the infoldings of the inner membrane of a mitochondrion.
Top

3. any anatomical structure resembling a crest.
Top

Back  -    New Search

Crohn's disease (krohnz) n.

a condition in which segments of the alimentary tract become inflamed, thickened, and ulcerated. It usually affects the terminal part of the ileum; its acute form (acute ileitis ) sometimes mimics appendicitis. Chronic disease often causes partial obstruction of the intestine, leading to pain, diarrhoea, and malabsorption. Alternative names: regional enteritis , regional ileitis . [B. B. Crohn (1884–1983), US physician]

Back  -    New Search

cromolyn sodium (kroh-m-lin) n.

a drug used to prevent and treat asthma and allergic bronchitis. It is administered by inhalation and may cause throat irritation. Trade name: Intal .

Back  -    New Search

cross-dressing (kros-dres-ing) n.

see TRANSVESTISM.

Back  -    New Search

cross-infection (kros-in-fek-shn) n.

the transfer of infection from one patient to another in hospital.

Back  -    New Search

crotamiton (kroh-t-my-tn) n.

a drug that destroys mites and is used to treat scabies and similar skin infections and also to relieve itching. It is applied to the skin as a lotion or ointment. Trade name: Eurax .

Back  -    New Search

croup (kroop) n.

acute inflammation and obstruction of of the respiratory tract, involving the larynx and main air passages, in young children (usually aged between six months and three years). The usual cause is a virus infection but bacterial secondary infection can occur. The symptoms are those of laryngitis, accompanied by harsh difficult breathing (see STRIDOR), a rising pulse rate, restlessness, and cyanosis.

Back  -    New Search

crown (krown) n.

1 the part of a tooth normally visible in the mouth and usually covered by enamel.

2 a dental restoration that covers most or all of the natural crown.
Top

3. see CORONA.
Top

Back  -    New Search

crowning (krown-ing) n.

the stage of labour when only the upper part of the infant's head is visible, encircled by, and just passing through, the vaginal opening.

Back  -    New Search

cruciate ligaments (krew-shi-ayt) pl. n.

a pair (anterior and posterior) of ligaments inside each knee joint. Damage to the cruciate ligaments is a common sports injury, especially in football players.

Back  -    New Search

crude rate (krood) n.

the total number of events (e.g. cases of lung cancer) expressed as a percentage (or rate per 1000, etc.) of the, whole population.

Back  -    New Search

crural (kroor-l) adj.

1 relating to the thigh or leg.

2 relating to the crura cerebri (see CRUS).
Top

Back  -    New Search

crus (kruus) n. (pl. crura)

an elongated process or part of a structure. c. cerebri one of two symmetrical nerve tracts situated between the medulla oblongata and the cerebral hemispheres.

Back  -    New Search

crush syndrome (krush) n.

the condition resulting from crushing accidents in which large areas of muscle are damaged, characterized by severe shock resulting from blood and fluid loss and oliguria leading to kidney failure.

Back  -    New Search

cry- (cryo-) prefix

denoting cold.

Back  -    New Search

cryaesthesia (kry-iss-theez-i) n.

1 exceptional sensitivity to low temperature.

2 a sensation of coldness.
Top

Back  -    New Search

cryoprecipitate (kry-oh-pri-sip-i-tt) n.

a precipitate produced by freezing and thawing under controlled conditions, such as the residue obtained from fresh frozen blood plasma that has been thawed at 4°C. This residue is used in the control of bleeding in haemophilia.

Back  -    New Search

cryopreservation (kry-oh-prez-er-vay-shn) n.

preservation of tissues by freezing.

Back  -    New Search

cryoprobe (kry-oh-prohb) n.

an instrument used in cryosurgery, which has a fine tip cooled by allowing carbon dioxide or nitrous oxide gas to expand within it.

Back  -    New Search

cryoretinopexy (kry-oh-ret-i-noh-pek-si) n.

the use of extreme cold to freeze areas of weak or torn retina in order to cause scarring and seal breaks. It is used in cryosurgery for retinal detachment.

Back  -    New Search

cryosurgery (kry-oh-ser-jer-i) n.

the use of extreme cold in a localized part of the body to freeze and destroy unwanted tissues. Cryosurgery is commonly used for the treatment of retinal detachment, the destruction of certain bone tumours, and the obliteration of skin blemishes. See CRYOPROBE.

Back  -    New Search

cryotherapy (kry-oh-th'e-r-pi) n.

the use of cold in the treatment of disorders. See CRYOSURGERY, HYPOTHERMIA. Compare THERMOTHERAPY.

Back  -    New Search

crypt (kript) n.

a small sac, follicle, or cavity; for example, the crypts of Lieberkühn (see LIEBERKÜHN'S GLANDS).

Back  -    New Search

crypt- (crypto-) prefix

denoting concealed.

Back  -    New Search

cryptococcosis (torulosis) (krip-toh-kok-oh-sis) n.

a disease caused by the fungus Cryptococcus neoformans, which attacks the lung, resulting in a solid tumour-like mass (toruloma ). It may spread to the brain, leading to meningitis; this can occur as an opportunistic infection in those suffering from AIDS.

Back  -    New Search

cryptogenic (krip-toh-jen-ik) adj.

of obscure or unknown cause.

Back  -    New Search

cryptomenorrhoea (krip-toh-men--ree-) n.

absence of blood flow when the internal symptoms of menstruation are present. The condition may arise because the hymen lacks an opening (see IMPERFORATE (HYMEN)) or because of some other obstruction.

Back  -    New Search

cryptorchidism (cryptorchism) (krip-or-kid-izm) n.

the condition in which the testes fail to descend into the scrotum and are retained within the abdomen or inguinal canal.
—cryptorchid adj., n.

Back  -    New Search

cryptosporidiosis (krip-toh-sper-id-i-oh-sis) n.

an intestinal infection of mammals and birds caused by parasitic protozoa of the genus Cryptosporidium, which is usually transmitted to humans via farm animals. Ingestion of water or milk contaminated with infective oocysts results in severe diarrhoea and abdominal cramps, caused by release of a toxin. Most patients recover in 7–14 days, but the disease can persist in the immunocompromised (including AIDS patients), the elderly, and young children.

Back  -    New Search

CSF n.

see CEREBROSPINAL FLUID.

Back  -    New Search

CT scanner (computerized tomography scanner) n.

an X-ray scanner incorporating a computer, used to provide an integrated three-dimensional image of the soft structures of the body. See COMPUTERIZED TOMOGRAPHY.

Back  -    New Search

cubital (kew-bit'l) adj.

relating to the elbow or forearm. c. fossa the depression at the front of the elbow.

Back  -    New Search

cuboid bone (kew-boid) n.

the outer bone of the tarsus, which articulates with the fourth and fifth metatarsal bones in front and with the calcaneus (heel bone) behind.

Back  -    New Search

cuirass (kwi-ras) n.

see RESPIRATOR.

Back  -    New Search

culdocentesis (kul-doh-sen-tee-sis) n.

see COLPOTOMY.

Back  -    New Search

culdoscope (kul-doh-skohp) n.

a tubular instrument with lenses and a light source, used for direct observation of the uterus, ovaries, and Fallopian tubes (culdoscopy ). The instrument is passed through the wall of the vagina behind to the neck of the uterus. The culdoscope has now been largely replaced by the laparoscope.

Back  -    New Search

culture (kul-cher)

1 n. a population of microorganisms, usually bacteria, grown in a solid or liquid laboratory medium (c. medium ), which is usually agar, broth, or gelatin. stock c. a permanent bacterial culture, from which subcultures are made. See also TISSUE CULTURE.

2 vb. to grow bacteria or other microorganisms in cultures.
Top

Back  -    New Search

cumulative action (kew-mew-l-tiv) n.

the toxic effects of a drug produced by repeated administration of small doses at intervals that are not long enough for it to be either broken down or excreted by the body.

Back  -    New Search

cuneiform bones (kew-ni-form) pl. n.

three bones in the tarsus that articulate with the first, second, and third metatarsal bones in front. All three bones articulate with the navicular bone behind.

Back  -    New Search

cupola (kew-p-l) n.

1 the small dome at the end of the cochlea.

2 any of several dome-shaped anatomical structures.
Top

Back  -    New Search

curare (kew-rar-i) n.

an extract from the bark of South American trees (Strychnos and Chondodendron species) that relaxes and paralyses voluntary muscle. Curare was formerly employed to control the muscle spasms of tetanus and, more recently, as a muscle relaxant in surgical operations. It has now been replaced in surgery by tubocurarine.

Back  -    New Search

curettage (kewr-i-tij) n.

the scraping of the skin or the internal surface of an organ or body cavity by means of a spoon-shaped instrument (curette ). Curettage is usually performed to remove diseased tissue or to obtain a specimen for diagnostic purposes. See also DILATATION AND CURETTAGE.

Back  -    New Search

curette (kewr-et) n.

see CURETTAGE.

Back  -    New Search

curie (kewr-ee) n.

a former unit for expressing the activity of a radioactive substance. It has been replaced by the becquerel. Symbol: Ci.

Back  -    New Search

Curling's ulcers (ker-lingz) pl. n.

gastric or duodenal ulcers associated with stress from severe injury or major burns. [T. B. Curling (1811–88), British surgeon]

Back  -    New Search

Cushing's syndrome (kuush-ingz) n.

the condition resulting from excess amounts of corticosteroid hormones in the body. Symptoms include weight gain, reddening of the face and neck, excess growth of body and facial hair, raised blood pressure, loss of mineral from the bones (osteoporosis), raised blood glucose levels, and sometimes mental disturbances. The syndrome may be due to overstimulation of the adrenal glands by excessive amounts of the hormone ACTH, secreted either by a tumour of the pituitary gland (Cushing's disease ) or by a malignant tumour in the lung or elsewhere. [H. W. Cushing (1869–1939), US surgeon]

Back  -    New Search

cusp (kusp) n.

1 any of the cone-shaped prominences on the teeth, especially the premolars and molars.

2 a pocket or fold of the membrane lining the heart or of the layer of the wall of a vein, several of which form a valve. When the blood flows backwards the cusps fill up and become distended, so closing the valve.
Top

Back  -    New Search

cutaneous (kew-tay-nis) adj.

relating to the skin.

Back  -    New Search

cuticle (kew-ti-kl) n.

1 the epidermis of the skin.

2 a layer of solid or semisolid material that is secreted by and covers an epithelium.
Top

3 a layer of cells, such as the outer layer of cells in a hair.
Top

Back  -    New Search

cutis (kew-tis) n.

see SKIN.

Back  -    New Search

CVP n.

see CENTRAL VENOUS PRESSURE.

Back  -    New Search

CVS n.

see CHORIONIC VILLUS SAMPLING.

Back  -    New Search

cyan- (cyano-) prefix

denoting blue.

Back  -    New Search

cyanide (sy--nyd) n.

any of the notoriously poisonous salts of hydrocyanic acid. Cyanides combine with and render inactive the enzymes of the tissues responsible for cellular respiration, and therefore they kill extremely quickly.

Back  -    New Search

cyanocobalamin (vitamin B_12) (sy--noh-koh-bal--min) n.

see VITAMIN B.

Back  -    New Search

cyanosis (sy--noh-sis) n.

a bluish discoloration of the skin and mucous membranes resulting from an inadequate amount of oxygen in the blood. Cyanosis is associated with heart failure, lung diseases, the breathing of oxygen-deficient atmospheres, and asphyxia. Cyanosis is also seen in blue babies, because of congenital heart defects.
—cyanotic adj.

Back  -    New Search

cybernetics (sy-ber-net-iks) n.

the science of communication processes and automatic control systems in both machines and living things: a study linking the working of the brain and nervous system with the functioning of computers and automated feedback devices. See also BIONICS.

Back  -    New Search

cycl- (cyclo-) prefix

denoting1 cycle or cyclic.

2 the ciliary body.
Top

Back  -    New Search

cyclical vomiting (sy-klik-l) n.

recurrent attacks of vomiting, often associated with acidosis, occurring in children but with no apparent cause.

Back  -    New Search

cyclitis (sy-kly-tis) n.

inflammation of the ciliary body of the eye (see UVEITIS).

Back  -    New Search

cyclizine (sy-kliz-een) n.

a drug with antihistamine properties, administered by mouth to prevent and relieve nausea and vomiting in motion sickness, vertigo, disorders of the inner ear, and postoperative sickness. Trade name: Valoid .

Back  -    New Search

cycloablation (sy-kloh--blay-shn) n.

the destruction of part of the ciliary body of the eye to reduce the production of aqueous humour and hence reduce intraocular pressure. It is used in the treatment of advanced glaucoma resistant to other forms of treatment.

Back  -    New Search

cyclocryotherapy (sy-kloh-kry-oh-th'e-r-pi) n.

the destruction of part of the ciliary body by freezing. It is used to reduce intraocular pressure in the control of glaucoma.

Back  -    New Search

cyclodialysis (sy-kloh-dy-al-i-sis) n.

an operation for glaucoma in which part of the ciliary body is separated from its attachment to the sclera. The aim is to improve the drainage of fluid and thus reduce the pressure within the eye.

Back  -    New Search

cyclopenthiazide (sy-kloh-pen-th'y--zyd) n.

a diuretic administered by mouth to treat oedema, high blood pressure, and heart failure. Trade name: Navidrex .

Back  -    New Search

cyclopentolate (sy-kloh-pen-t-layt) n.

a drug, similar to atropine, that is used in eye drops to paralyse the ciliary muscles and dilate the pupil for eye examinations and to treat some types of eye inflammation. Trade names: Minims cyclopentolate , Mydrilate .

Back  -    New Search

cyclophosphamide (sy-kloh-fos-f-myd) n.

a drug administered by mouth or injection to treat some cancers, often in combination with other cytotoxic drugs. It also has immunosuppressive properties and is used in prolonging the survival of tissue transplants and in other conditions requiring reduced immune response. Trade name: Endoxana .

Back  -    New Search

cyclophotoablation (sy-kloh-foh-toh--blay-shn) n.

the use of light or lasers to destroy the ciliary body of the eye in order to reduce production of aqueous humour and hence reduce intraocular pressure. It is used in the treatment of glaucoma.

Back  -    New Search

cycloplegia (sy-kloh-plee-ji) n.

paralysis of the ciliary muscle of the eye (see CILIARY BODY). This causes inability to alter the focus of the eye and is usually accompanied by paralysis of the muscles of the pupil, resulting in fixed dilation of the pupil (mydriasis).

Back  -    New Search

cyclopropane (sy-kloh-proh-payn) n.

a general anaesthetic, administered by inhalation for all types of surgical operation. It can cause postoperative nausea, vomiting, and headache.

Back  -    New Search

cycloserine (sy-kloh-seer-een) n.

an antibiotic, active against a wide range of bacteria, that may be used as supporting treatment in tuberculosis. It is administered by mouth.

Back  -    New Search

cyclosporin A (sy-kloh-spo-rin) n.

a drug that suppresses the immune system and is administered to prevent and treat rejection of a transplanted organ or bone marrow. Trade name: Sandimmun .

Back  -    New Search

cyclothymia (sy-kloh-th'y-mi) n.

the occurrence of marked swings of mood from cheerfulness to misery. These fluctuations usually represent a personality disorder, and are not as great as those of manic-depressive psychosis.

Back  -    New Search

cyclotomy (sy-klot-mi) n.

surgical incision of the ciliary body of the eye.

Back  -    New Search

cyesis (sy-ee-sis) n.

pregnancy. See also PSEUDOCYESIS.

Back  -    New Search

cyn- (cyno-) prefix

denoting a dog or dogs.

Back  -    New Search

cyproheptadine (sy-proh-hep-t-deen) n.

a potent antihistamine administered by mouth to treat allergies and itching skin conditions; it is also used to stimulate the appetite. Trade name: Periactin .

Back  -    New Search

cyproterone (cyproterone acetate, CPA) (sy-proh-ter-ohn) n.

a steroid drug that inhibits the effects of male sex hormones (see ANTI-ANDROGEN) and is used to treat various sexual disorders and advanced prostate cancer in men. It is administered by mouth. Trade names: Androcur , Cyprostat .

Back  -    New Search

cyst (sist) n.

1 an abnormal sac or closed cavity lined with epithelium and filled with liquid or semisolid matter. There are many varieties of cysts occurring in different parts of the body. See DERMOID CYST, FIMBRIAL CYST, HYDATID, OVARIAN CYST, RETENTION CYST, SEBACEOUS CYST.

2 a dormant stage produced during the life cycle of certain protozoan parasites of the alimentary canal, including Giardia and Entamoeba.
Top

3 a structure formed by and surrounding the larvae of certain parasitic worms.
Top

Back  -    New Search

cyst- (cysto-) prefix

denoting 1 a bladder, especially the urinary bladder.

2 a cyst.
Top

Back  -    New Search

cystadenoma (sis-tad-i-noh-m) n.

an adenoma showing a cystic structure.

Back  -    New Search

cystalgia (sis-tal-ji) n.

pain in the urinary bladder. This is common in cystitis and when there are stones in the bladder and is occasionally present in bladder cancer.

Back  -    New Search

cystectomy (sis-tek-tmi) n.

surgical removal of the urinary bladder. The ureters draining the urine from the kidneys may be reimplanted into the colon (see URETEROSIGMOIDOSTOMY) or into the ileum (see ILEAL CONDUIT).

Back  -    New Search

cysteine (sis-ti-een) n.

a sulphur-containing amino acid that is an important constituent of many enzymes.

Back  -    New Search

cystic (sis-tik) adj.

1 of, relating to, or characterized by cysts.

2 of or relating to the gall bladder or urinary bladder. c. duct see BILE DUCT.
Top

Back  -    New Search

cysticercosis (sis-ti-ser-koh-sis) n.

a disease caused by the presence of tapeworm larvae (see CYSTICERCUS) of the species Taenia solium in any of the body tissues. The presence of cysticerci in the muscles causes pain and weakness; in the brain the symptoms are more serious, including mental deterioration, paralysis, giddiness, epileptic attacks, and convulsions.

Back  -    New Search

cysticercus (bladderworm) (sis-ti-ser-ks) n.

a larval stage of some tapeworms in which the scolex and neck are invaginated into a large fluid-filled cyst. See CYSTICERCOSIS.

Back  -    New Search

cystic fibrosis (fibrocystic disease of the pancreas, mucoviscidosis) n.

a hereditary disease affecting cells of the exocrine glands; the faulty gene responsible has been identified as lying on chromosome no. 7 and is recessive, i.e. both parents of the patient can be carriers without being affected by the disease. The abnormality results in the production of thick mucus, which obstructs the intestinal glands (causing meconium ileus in newborn babies), pancreas (causing deficiency of pancreatic enzymes resulting in malabsorption and failure to thrive), and bronchi (causing bronchiectasis). Respiratory infections, which may be severe, are a common complication.

Back  -    New Search

cystine (sis-teen) n.

see AMINO ACID.

Back  -    New Search

cystinosis (sis-ti-noh-sis) n.

an inborn defect in the metabolism of amino acids, leading to abnormal accumulation of the amino acid cystine in the blood, kidneys, and lymphatic system. See also FANCONI SYNDROME.

Back  -    New Search

cystinuria (sis-tin-yoor-i) n.

an inborn error of metabolism resulting in excessive excretion of the amino acid cystine in the urine due to a defect of reabsorption by the kidney tubules. It may lead to the formation of cystine stones in the kidney.

Back  -    New Search

cystitis (sis-ty-tis) n.

inflammation of the urinary bladder, often caused by infection. It is usually accompanied by the desire to pass urine frequently, with a degree of burning.

Back  -    New Search

cystitome (sis-ti-tohm) n.

a small knife with a tiny curved or hooked blade, used to cut the lens capsule in some operations for cataract.

Back  -    New Search

cystocele (sis-t-seel) n.

prolapse of the base of the bladder in women. It is usually due to weakness of the pelvic floor after childbirth and causes bulging of the anterior wall of the vagina on straining.

Back  -    New Search

cystography (sis-tog-rfi) n.

X-ray examination of the urinary bladder after the injection of a contrast medium. The X-ray photographs or films thus obtained are known as cystograms .

Back  -    New Search

cystolithiasis (sis-toh-lith-l--sis) n.

the presence of stones (calculi) in the urinary bladder. The stones cause pain, the passage of bloody urine, and interruption of the urinary stream and should be removed surgically. See CALCULUS.

Back  -    New Search

cystometer (sis-tom-it-er) n.

an apparatus for measuring pressure within the bladder.
—cystometry n.

Back  -    New Search

cystopexy (vesicofixation) (sis-toh-peksi) n.

a surgical operation to fix the urinary bladder (or a portion of it) in a different position. It may be performed as part of the repair or correction of a prolapsed bladder.

Back  -    New Search

cystoplasty (sis-toh-plasti) n.

the operation of enlarging the capacity of the bladder by incorporating a segment of bowel. clam c. an operation in which the bladder is cut across longitudinally from one side of the neck to the other side through the dome (fundus) of the bladder and a length of ileum or colon is inserted as a patch. See also ILEOCAECOCYSTOPLASTY, ILEOCYSTOPLASTY.

Back  -    New Search

cystoscopy (sis-tos-kpi) n.

examination of the bladder by means of an instrument (cystoscope ) inserted via the urethra.

Back  -    New Search

cystostomy (sis-tost-mi) n.

the operation of creating an artificial opening between the bladder and the anterior abdominal wall. This provides a temporary or permanent drainage route for urine.

Back  -    New Search

cystotomy (sis-tot-mi) n.

surgical incision into the urinary bladder, usually by cutting through the abdominal wall above the pubic symphysis (suprapubic c. ).

Back  -    New Search

cyt- (cyto-) prefix

denoting 1 cell(s).

2 cytoplasm.
Top

Back  -    New Search

cytarabine (sy-ta-r-been) n.

a cytotoxic drug that is used to suppress the symptoms of some types of leukaemia. It is administered by injection and can damage the bone marrow, leading to various blood cell disorders. Trade names: Alexan , Cytosar .

Back  -    New Search

-cyte suffix

denoting a cell.

Back  -    New Search

cytochemistry (sy-toh-kem-istri) n.

the study of chemical compounds and their activities in living cells.

Back  -    New Search

cytogenetics (sy-toh-ji-net-iks) n.

a science that links the study of inheritance (genetics) with that of cells (cytology); it is concerned mainly with the study of the chromosomes, especially their origin, structure, and functions.

Back  -    New Search

cytokinesis (sy-toh-ki-nee-sis) n.

see KARYOKINESIS.

Back  -    New Search

cytology (sy-tol-ji) n.

the study of the structure and function of cells. aspiration c. the aspiration of specimens of cells from tumours or cysts through a hollow needle, using a syringe, and their subsequent examination under the microscope after suitable preparation (by staining, etc.). cervical c. the microscopic examination of cells obtained by scraping the cervix. See CERVICAL (SMEAR). exfoliative c. the microscopic examination of cells that have already been shed, used in the diagnosis of various diseases. See also BIOPSY.
—cytological adj.

Back  -    New Search

cytolysis (sy-tol-i-sis) n.

the breakdown of cells, particularly by destruction of their outer membranes.

Back  -    New Search

cytomegalovirus (CMV) (sy-toh-meg--loh-vy-rs) n.

a virus belonging to the herpesvirus group. It normally causes only mild symptoms, but in immunocompromised individuals its effects can be more severe; if contracted by a pregnant woman it may give rise to congenital mental handicap in her child.

Back  -    New Search

cytometer (sy-tom-it-er) n.

an instrument for determining the number of cells in a given quantity of fluid, such as blood, cerebrospinal fluid, or urine. See HAEMOCYTOMETER.

Back  -    New Search

cytopenia (sy-toh-pee-ni) n.

a deficiency of one or more of the various types of blood cells. See EOSINOPENIA, ERYTHROPENIA, LYMPHOPENIA, NEUTROPENIA, PANCYTOPENIA, THROMBOCYTOPENIA.

Back  -    New Search

cytoplasm (sy-toh-plazm) n.

the jelly-like substance that surrounds the nucleus of a cell. See also PROTOPLASM.
—cytoplasmic adj.

Back  -    New Search

cytosine (sy-toh-seen) n.

one of the nitrogen-containing bases (see PYRIMIDINE) that occurs in the nucleic acid DNA.

Back  -    New Search

cytosome (sy-toh-sohm) n.

the part of a cell that is outside the nucleus.

Back  -    New Search

cytotoxic drug (sy-toh-toks-ik) n.

a drug that damages or destroys cells and is used to treat various types of cancer. Examples are amsacrine, cisplatin, cyclophosphamide, cytarabine, mustine, and anthracycline antibiotics. They destroy cancer cells by inhibiting cell division but they also affect normal cells, particularly in bone marrow, skin, stomach lining, and fetal tissue, and dosage must be carefully controlled. See also ANTIMETABOLITE.

Back  -    New Search

D

dacarbazine (DTIC) (da-kah-b-zeen) n.

a drug used in the treatment of certain cancers, including Hodgkin's disease and malignant melanoma.

Back  -    New Search

dacry- (dacryo-) prefix

denoting 1 tears.

2 the lacrimal apparatus.
Top

Back  -    New Search

dacryoadenitis (dak-ri-oh-ad-i-ny-tis) n.

inflammation of the tear-producing gland. See LACRIMAL (APPARATUS).

Back  -    New Search

dacryocystitis (dak-ri-oh-sis-ty-tis) n.

inflammation of the lacrimal sac, usually occurring when the duct draining the tears into the nose is blocked. See LACRIMAL (APPARATUS).

Back  -    New Search

dacryocystorhinostomy (DCR) (dak-ri-oh-sis-toh-ry-nost-mi) n.

an operation to relieve blockage of the nasolacrimal duct (which drains tears into the nose), in which a communication is made between the lacrimal sac and the nose by removing the intervening bone. See DACRYOCYSTITIS, LACRIMAL (APPARATUS).

Back  -    New Search

dacryolith (dak-ri-oh-lith) n.

a stone in the lacrimal canaliculus or lacrimal sac. See LACRIMAL (APPARATUS).

Back  -    New Search

dacryoma (dak-ri-oh-m) n.

a harmless tumour-like swelling obstructing any of the ducts associated with the lacrimal apparatus.

Back  -    New Search

dactyl- prefix

denoting the digits (fingers or toes).

Back  -    New Search

dactylion (dak-til-in) n.

see SYNDACTYLY.

Back  -    New Search

dactylitis (dak-ti-ly-tis) n.

inflammation of a finger or toe caused by bone infection (as in tuberculous osteomyelitis) or rheumatic disease or seen in infants with sickle-cell disease.

Back  -    New Search

dactylology (dak-ti-lol-ji) n.

the representation of speech by finger movements: sign language.

Back  -    New Search

Daltonism (protanopia) (dawl-tn-izm) n.

red-blindness: a defect in colour vision in which a person cannot distinguish between reds and greens. The term has been used to refer to colour blindness in general. [J. Dalton (1766–1844), British chemist]

Back  -    New Search

danazol (dan--zol) n.

a synthetic progestogen that inhibits the secretion by the pituitary gland of gonadotrophins. Administered by mouth, it is used to treat precocious puberty, breast enlargement in males (gynaecomastia), excessively heavy menstrual periods, and endometriosis. Trade name: Danol .

Back  -    New Search

D and C n.

see DILATATION AND CURETTAGE.

Back  -    New Search

dandruff (dan-druf) n.

visible scaling from the surface of the scalp, associated with the presence of the yeast Pityrosporum ovale. It is the precursor of seborrhoeic eczema of the scalp, in which there is a degree of inflammation in addition to the greasy scaling. Dandruff can be controlled by shampoos containing tar, selenium sulphide, zinc pyrithione, or imidazole antifungals. Medical name: pityriasis capitis .

Back  -    New Search

Dandy-Walker syndrome (dan-di wawk-er) n.

a form of cerebral palsy in which the cerebellum is usually the part of the brain affected. It leads to unsteadiness of balance and an abnormal gait and may be associated with hydrocephalus. [W. E. Dandy (1886–1946) and A. E. Walker (1907– ), US surgeons]

Back  -    New Search

dangerous drugs (dayn-jer-s) pl. n.

see MISUSE OF DRUGS ACT 1971.

Back  -    New Search

dantrolene (dan-troh-leen) n.

a muscle relaxant drug used to relieve muscle spasm in such conditions as cerebral palsy, multiple sclerosis, or spinal cord injury. It is administered by mouth or by injection. Trade name: Dantrium .

Back  -    New Search

dapsone (dap-sohn) n.

a drug (see SULPHONE) administered by mouth or injection to treat leprosy and dermatitis herpetiformis.

Back  -    New Search

dark adaptation (dark) n.

the changes that take place in the retina and pupil of the eye enabling vision in very dim light. See ROD. Compare LIGHT ADAPTATION.

Back  -    New Search

daunorubicin (daw-noh-roo-bi-sin) n.

an antibiotic that interferes with DNA synthesis and is used in the treatment of acute leukaemia. It is administered by injection.

Back  -    New Search

day blindness (day) n.

comparatively good vision in poor light but poor vision in good illumination. The condition is usually congenital and associated with poor visual acuity and defective colour vision. Medical name: hemeralopia . Compare NIGHT BLINDNESS.

Back  -    New Search

day-case surgery n.

surgical procedures that can be performed in a single day, without the need to admit the patient for an overnight stay in hospital. Examples include removal of many breast lesions, dilatation and curettage, and operations for hernia and varicose veins. Special units are established in many hospitals.

Back  -    New Search

day hospital n.

see HOSPITAL.

Back  -    New Search

DDAVP n.

see DESMOPRESSIN.

Back  -    New Search

DDT (chlorophenothane, dicophane) n.

a powerful insecticide that was formerly widely used. The quantities now present in the environment – in the form of stores accumulated in animal tissues – have led to its use being restricted.

Back  -    New Search

de- prefix

denoting 1 removal or loss.

2 reversal.
Top

Back  -    New Search

dead space (ded) n.

1 any part of the respiratory tract containing air that does not participate in the exchange of oxygen and carbon dioxide.

2 a cavity that remains in an incompletely closed wound, in which blood may accumulate and delay healing.
Top

Back  -    New Search

deafness (def-nis) n.

partial or total loss of hearing in one or both ears. conductive d. deafness that is due to a defect in the conduction of sound from the external ear to the inner ear. This may be due to perforations of the eardrum, fluid or infection in the middle ear (see GLUE EAR, OTITIS (MEDIA)), or disorders of the small bones in the middle ear (ossicles). sensorineural d. (perceptive d. ) deafness that may be due to a lesion of the cochlea in the inner ear, the auditory nerve, or the auditory centres in the brain. See also COCHLEAR IMPLANT, HEARING AID, RINNE'S TEST, WEBER'S TEST.

Back  -    New Search

deamination (dee-ami-nay-shn) n.

a process that occurs in the liver during the metabolism of amino acids. The amino group (-NH_2) is removed from an amino acid and converted to ammonia, which is ultimately converted to urea and excreted.

Back  -    New Search

death (deth) n.

absence of vital functions. brain d. permanent functional death of the centres in the brainstem that control breathing, heart rate, and other vital reflexes (including pupillary responses). Usually two independent medical opinions are required before brain death is agreed, but organs such as kidneys may then legally be removed for transplantation surgery before the heart has stopped.

Back  -    New Search

death certificate n.

a medical certificate stating the cause of a person's death, usually also stating the deceased's marital status, occupation, and age.

Back  -    New Search

debility (di-bil-iti) n.

physical weakness; loss of strength and power.

Back  -    New Search

debridement (di-breed-mnt) n.

the process of cleaning an open wound by removal of foreign material and dead tissue, so that healing may occur without hindrance.

Back  -    New Search

debrisoquine (deb-ris-oh-kween) n.

a potent drug administered by mouth to treat high blood pressure (hypertension). Trade name: Declinax .

Back  -    New Search

dec- (deca-) prefix

denoting ten.

Back  -    New Search

Decadron (dek--dron) n.

see DEXAMETHASONE.

Back  -    New Search

decalcification (dee-kal-sifi-kay-shn) n.

loss or removal of calcium salts from a bone or tooth.

Back  -    New Search

decapitation (di-kapi-tay-shn) n.

removal of the head, usually the head of a dead fetus to enable delivery to take place. This procedure is now very rare.

Back  -    New Search

decapsulation (decortication) (dee-kaps-yoo-lay-shn) n.

the surgical removal of a capsule from an organ; for example, the stripping of the membrane that envelops the kidney or of the inflammatory capsule that encloses a chronic abscess, as in the treatment of empyema.

Back  -    New Search

decay (di-kay) n.

(in bacteriology) the decomposition of organic matter due to microbial action.

Back  -    New Search

deci- prefix

denoting a tenth.

Back  -    New Search

decidua (di-sid-yoo-) n.

the modified mucous membrane that lines the wall of the uterus during pregnancy and is shed with the afterbirth at parturition (see ENDOMETRIUM). d. basalis the region of the decidua where the embryo is attached. d. capsularis the thin layer of the decidua that covers the embryo. d. parietalis the region of the decidua that is not in contact with the embryo.
—decidual adj.

Back  -    New Search

deciduoma (di-sid-yoo-oh-m) n.

a mass of tissue within the uterus that is derived from remnants of decidua. See also CHORIONEPITHELIOMA (MALIGNANT DECIDUOMA).

Back  -    New Search

decompensation (dee-kom-pen-say-shn) n.

inability of the heart to maintain an adequate circulation in the face of an increased workload or some structural defect.

Back  -    New Search

decomposition (dee-kom-p-zish-n) n.

the gradual disintegration of dead organic matter, usually foodstuffs or tissues, by the chemical action of bacteria and/or fungi.

Back  -    New Search

decompression (dee-km-presh-n) n.

1 the reduction of pressure on an organ or part of the body by surgical intervention. Raised pressure in the fluid of the brain can be lowered by cutting into the dura mater; cardiac compression – the abnormal presence of blood or fluid round the heart – can be cured by cutting the pericardium.

2 the gradual reduction of atmospheric pressure for deep-sea divers. See COMPRESSED AIR ILLNESS.
Top

Back  -    New Search

decompression sickness n.

see COMPRESSED AIR ILLNESS.

Back  -    New Search

decongestant (dee-kn-jest-nt) n.

an agent that reduces or relieves nasal congestion. Most nasal decongestants are sympathomimetic drugs, which are applied either locally, in the form of nasal sprays or drops, or taken by mouth.

Back  -    New Search

decortication (dee-kor-ti-kay-shn) n.

1 the removal of the outside layer (cortex) from an organ or structure, such as the kidney.

2 an operation for removing the blood clot and scar tissue that forms after bleeding into the chest cavity.
Top

3 see DECAPSULATION.
Top

Back  -    New Search

decubitus (di-kew-bit-s) n.

the recumbent position.

Back  -    New Search

decubitus ulcer n.

see BEDSORE.

Back  -    New Search

decussation (dee-kus-ay-shn) n.

a point at which two or more structures of the body cross to the opposite side. The term is used particularly for the point at which nerve fibres cross over in the central nervous system.

Back  -    New Search

deep vein thrombosis (DVT) n.

see PHLEBOTHROMBOSIS.

Back  -    New Search

defecation (def-i-kay-shn) n.

the expulsion of faeces through the anus.

Back  -    New Search

defence mechanism (di-fenss) n.

the means whereby an undesirable impulse can be avoided or controlled. Defence mechanisms include repression, projection, reaction formation, sublimation, and splitting.

Back  -    New Search

deferent (def-er-nt) adj.

1 carrying away from or down from.

2 relating to the vas deferens.
Top

Back  -    New Search

defervescence (def-er-ves-ns) n.

the disappearance of a fever, a process that may occur rapidly or take several days.

Back  -    New Search

defibrillation (dee-fib-ri-lay-shn) n.

administration of a controlled electric shock to restore normal heart rhythm in cases of cardiac arrest due to ventricular fibrillation. The apparatus (defibrillator ) administers the shock either through electrodes placed on the chest wall over the heart or directly to the heart after the chest has been opened surgically.

Back  -    New Search

defibrination (dee-fib-ri-nay-shn) n.

the removal of fibrin, one of the plasma proteins that causes coagulation, from a sample of blood.

Back  -    New Search

deficiency disease (di-fish-n-si) n.

any disease caused by the lack of an essential nutrient in the diet. Such nutrients include vitamins, essential amino acids, and essential fatty acids.

Back  -    New Search

degeneration (di-jen-er-ay-shn) n.

the deterioration and loss of specialized function of the cells of a tissue or organ. The changes may be caused by a defective blood supply or by disease. Degeneration may involve the deposition of calcium salts, of fat (see FATTY DEGENERATION), or of fibrous tissue in the affected organ or tissue. See also INFILTRATION.

Back  -    New Search

deglutition (dee-gloo-tish-n) n.

see SWALLOWING.

Back  -    New Search

dehiscence (di-hiss-ns) n.

a splitting open, as of a surgical wound.

Back  -    New Search

dehydration (dee-hy-dray-shn) n.

loss or deficiency of water in body tissues. The condition may result from inadequate water intake and/or from excessive removal of water from the body; for example, by sweating, vomiting, or diarrhoea.

Back  -    New Search

dehydrogenase (dee-hy-droj--nayz) n.

see OXIDOREDUCTASE.

Back  -    New Search

déjà vu (day-zha-vew) n.

a vivid psychic experience in which immediately contemporary events seem to be a repetition of previous happenings. It is a symptom of some forms of epilepsy. See also JAMAIS VU.

Back  -    New Search

delayed suture (di-layd) n.

a technique used in the closure of contaminated wounds and wounds associated with tissue necrosis, such as are produced by missile injuries. The superficial layers of the wound are left open, to be closed later when the tissues have been cleaned.

Back  -    New Search

Delhi boil (del-i) n.

see ORIENTAL SORE.

Back  -    New Search

delirium (di-li-ri-m) n.

an acute disorder of the mental processes accompanying organic brain disease. It may be manifested by delusions, disorientation, hallucinations, or extreme excitement and occurs in metabolic disorders, intoxication, deficiency diseases, and infections. d. tremens a psychosis caused by alcoholism, usually seen as a withdrawal syndrome in chronic alcoholics. Features include anxiety, tremor, sweating, and vivid hallucinations.

Back  -    New Search

delivery (di-liv-ri) n.

see LABOUR.

Back  -    New Search

deltoid (del-toid) n.

a thick triangular muscle that covers the shoulder joint. It is responsible for raising the arm from the side of the body.

Back  -    New Search

delusion (di-loo-zhn) n.

an irrationally held belief that cannot be altered by rational argument. It may be a symptom of manic-depressive psychosis, schizophrenia, or an organic psychosis. See also PARANOIA.

Back  -    New Search

demarcation (dee-mar-kay-shn) n.

the marking of a limit or boundary. line of d. a red or black line marking the boundary between necrotic and healthy tissue in gangrene.

Back  -    New Search

demeclocycline (dee-mek-loh-sy-kleen) n.

an antibiotic that is active against a wide range of bacteria and is administered by mouth to treat various infections. Trade name: Ledermycin .

Back  -    New Search

dementia (di-men-sh) n.

a chronic or persistent disorder of behaviour and higher intellectual function due to organic brain disease. It is marked by memory disorders, changes in personality, deterioration in personal care, impaired reasoning ability, and disorientation. multi-infarct d. dementia resulting from the destruction of brain tissue by a series of small strokes. presenile d. dementia that occurs in young or middle-aged people. See ALZHEIMER'S DISEASE, PICK'S DISEASE.

Back  -    New Search

demi- prefix

denoting half.

Back  -    New Search

demography (di-mog-rfi) n.

the study of the populations of the world, their racial make-up, movements, birth rates, death rates, and other factors affecting the quality of life within them.

Back  -    New Search

demulcent (di-mul-snt) n.

a soothing agent that protects the mucous membranes and relieves irritation.

Back  -    New Search

demyelination (dee-my--li-nay-shn) n.

damage to the myelin sheaths surrounding the nerve fibres in the central or peripheral nervous system. Demyelination may be a primary disorder, as in multiple sclerosis.

Back  -    New Search

dendrite (den-dryt) n.

one of the shorter branching processes of the cell body of a neurone, which makes contact with other neurones at synapses and carries nerve impulses from them into the cell body.

Back  -    New Search

dendritic ulcer (den-drit-ik) n.

a branching ulcer of the surface of the cornea caused by herpes simplex virus.

Back  -    New Search

denervation (de-ner-vay-shn) n.

interruption of the nerve supply to the muscles and skin. A denervated area of skin loses all forms of sensation and its subsequent ability to heal and renew its tissues may be impaired.

Back  -    New Search

dengue (breakbone fever) (deng-i) n.

a viral disease that occurs throughout the tropics and subtropics; it is transmitted to man principally by the mosquito Aëdes aegypti. Symptoms include severe pains in the joints and muscles, headache, fever, and an irritating rash.

Back  -    New Search

denial (di-ny-l) n.

a psychological process in which an individual refuses to accept an aspect of reality. It is seen particularly in dying patients who refuse to accept their impending death.

Back  -    New Search

Denis Browne splint (den-iss brown) n.

a splint used for the correction of club-foot in early infancy. [Sir Denis J. W. Browne (1892–1967), British orthopaedic surgeon]

Back  -    New Search

dens (denz) n.

a tooth or tooth-shaped structure.

Back  -    New Search

dent- (denti-, dento-) prefix

denoting the teeth.

Back  -    New Search

dental auxiliary (den-t'l) n.

any of various assistants to a dentist. A dental hygienist performs scaling and instruction in oral hygiene under the prescription of the dentist. A dental nurse helps the dentist at the chairside by preparing materials, passing instruments, and aspirating fluids from the patient's mouth. A dental technician constructs dentures, crowns, and orthodontic appliances in the laboratory for the dentist. A dental therapist performs treatment on children under the direction of a dentist in the community dental services and in hospitals.

Back  -    New Search

dental caries n.

see CARIES.

Back  -    New Search

dental nurse n.

see DENTAL AUXILIARY.

Back  -    New Search

dentate (den-tayt) adj.

1 having teeth.

2 serrated; having toothlike projections.
Top

Back  -    New Search

dentifrice (dent-i-fris) n.

a powder or paste for cleaning the teeth. Toothpastes contain a fine abrasive to which are added flavouring and colouring materials.

Back  -    New Search

dentine (den-teen) n.

a hard tissue that forms the bulk of a tooth. The dentine of the crown is covered by enamel and that of the root by cementum.

Back  -    New Search

dentistry (den-tist-ri) n.

the profession concerned with care and treatment of diseases of the teeth, gums, and jaws.

Back  -    New Search

dentition (den-tish-n) n.

the number, type, and arrangement of the teeth as a whole in the mouth. permanent d. the 32 teeth usually present by the age of 21, made up of incisors, canines, premolars, and molars, primary d. the teeth of young children, which are progressively lost in preparation for the eruption of the permanent teeth. It consists of 20 teeth, made up of incisors, canines, and molars only.

Back  -    New Search

denture (den-cher) n.

a removable plate or frame bearing one or more false teeth. complete d. a denture replacing all the teeth in one jaw. partial d. a denture replacing some teeth, designed to restore function to the remaining teeth.

Back  -    New Search

deodorant (dee-oh-der-nt) n.

an agent that reduces or removes unpleasant body odours by destroying bacteria that live on the skin and break down sweat. Deodorant preparations often contain an antiseptic.

Back  -    New Search

deontology (dee-on-tol-ji) n.

an ethical approach stating that certain things must be done or principles followed, without consideration of whether or not this will lead to the best consequences in the particular circumstances.

Back  -    New Search

deoxycholic acid (dee-oks-i-koh-lik) n.

see BILE ACIDS.

Back  -    New Search

deoxycorticosterone (dee-oks-i-kor-ti-koh-steer-ohn) n.

a hormone, synthesized and released by the adrenal cortex, that regulates salt and water balance. See also CORTICOSTEROID.

Back  -    New Search

deoxyribonucleic acid (dee-oks-i-ry-boh-new-klee-ik) n.

see DNA.

Back  -    New Search

Department of Health (di-part-mnt) n.

a department of central government that supports the Secretary of State for Health in meeting his or her obligations, which include the National Health Service and the promotion and protection of the health of the nation.

Back  -    New Search

Department of Social Security n.

a department of central government that supports the Secretary of State for Social Security in meeting his or her obligations, which include the social services, National Insurance, and benefits for those with welfare needs.

Back  -    New Search

dependence (drug dependence) (di-pen-dns) n.

1 the physical and/or the psychological effects produced by the habitual taking of certain drugs, characterized by a compulsion to continue taking the drug. physical d. dependence in which withdrawal of the drug causes specific symptoms (withdrawal symptoms ), such as sweating, vomiting, or tremors, that are reversed by further doses. It may be induced by alcohol, morphine, heroin, and cocaine. psychological d. dependence in which repeated use of a drug induces reliance on it for a state of well-being and contentment, but there are no physical withdrawal symptoms if use of the drug is stopped. It may be induced by nicotine in tobacco, cannabis, and such drugs as barbiturates and amphetamines.

2 a state of reliance on others for aspects of self-care, sometimes used as a measure of nursing workload.
Top

Back  -    New Search

depersonalization (dee-per-s-n-ly-zay-shn) n.

a state in which a person feels himself becoming unreal or strangely altered, or feels that his mind is becoming separated from his body. Severe feelings of depersonalization occur in conditions such as anxiety neurosis, schizophrenia, and epilepsy. See also DEREALIZATION, OUT-OF-THE-BODY EXPERIENCE.

Back  -    New Search

depilatory (di-pil--ter-i) n.

an agent applied to the skin to remove hair.

Back  -    New Search

depolarization (dee-poh-l-ry-zay-shn) n.

the sudden surge of charged particles across the membrane of a nerve cell or of a muscle cell that accompanies a physicochemical change in the membrane and cancels out, or reverses, its resting potential to produce an action potential.

Back  -    New Search

depressant (di-pres-nt) n.

an agent that reduces the normal activity of any body system or function. Drugs such as general anaesthetics, barbiturates, and opiates are depressants of the central nervous system and respiration.

Back  -    New Search

depression (di-presh-n) n.

a mental state characterized by excessive sadness. Activity can be agitated or retarded and sleep, appetite, and concentration can be disturbed. Loss or frustration cause depression, which may be prolonged and disproportionate (dysthymic disorder; formerly called depressive neurosis ). Manic-depressive psychosis causes very severe depression, a major affective disorder. Treatment for depression is with antidepressant drugs, cognitive therapy, and/or psychotherapy. See also POSTNATAL (DEPRESSION).

Back  -    New Search

depressor (di-pres-er) n.

1 a muscle that causes lowering of part of the body.

2 a nerve that lowers blood pressure.
Top

Back  -    New Search

dequalinium (dek-w-lin-im) n.

an antiseptic, active against some bacteria and fungi, used as lozenges or paint to treat mouth and throat infections. Trade name: Labosept .

Back  -    New Search

Derbyshire neck (dar-bi-sher) n.

endemic goitre that was once common in Derbyshire due to lack of iodine in the soil and water.

Back  -    New Search

derealization (dee-ri-ly-zay-shn) n.

a feeling of unreality in which the environment is experienced as unreal and strange. It occurs in association with depersonalization or with the conditions that cause depersonalization.

Back  -    New Search

dereism (dee-ri-izm) n.

undirected fantasy thinking that fails to respect the realities of life. It may be a feature of schizophrenia.

Back  -    New Search

derm- (derma-, dermo-, dermat(o)-) prefix

denoting the skin.

Back  -    New Search

-derm suffix

denoting 1 the skin.

2 a germ layer.
Top

Back  -    New Search

dermal (der-ml) adj.

relating to or affecting the skin, especially the dermis.

Back  -    New Search

dermatitis (der-m-ty-tis) n.

an inflammatory condition of the skin, especially one in which outside agents play a primary role (compare ECZEMA). allergic contact d. dermatitis in which skin changes resembling those of eczema develop as a delayed reaction to contact with a particular allergen. The commonest example in women is nickel d. from jewellery, jean studs, etc.; in men chromium d. is relatively common. d. herpetiformis an uncommon very itchy rash with symmetrical blistering, especially on the knees, elbows, buttocks, and shoulders. It is associated with gluten sensitivity. primary irritant d. a condition that may occur in anyone who has sufficient contact with such irritants as acids, alkalis, solvents, and (especially) detergents. It is the commonest cause of occupational d. in hairdressers, nurses, cooks, etc. See also NAPKIN RASH. seborrhoeic d. see (SEBORRHOEIC) ECZEMA.

Back  -    New Search

dermatochalasis (der-m-toh-k-lay-sis) n.

redundant eyelid skin, which may cause drooping of the upper lid. It occurs as a result of ageing and is therefore seen only in middle-aged and elderly people. Compare BLEPHAROCHALASIS.

Back  -    New Search

dermatoglyphics (der-m-toh-glif-iks) n.

the study of the patterns of finger, palm, toe, and sole prints, which are unique to each individual. Abnormalities are found in those with chromosomal aberrations, e.g. Down's syndrome. Dermatoglyphics is of interest to anthropologists and also of value in criminology. See also FINGERPRINT.

Back  -    New Search

dermatology (der-m-tol-ji) n.

the medical specialty concerned with the diagnosis and treatment of skin disorders.
—dermatological adj. —dermatologist n.

Back  -    New Search

dermatome (der-m-tohm) n.

a surgical instrument used for cutting thin slices of skin in some skin grafting operations.

Back  -    New Search

dermatomycosis (der-m-toh-my-koh-sis) n.

any infection of the skin caused by fungi.

Back  -    New Search

dermatomyositis (der-m-toh-my-oh-sy-tis) n.

an inflammatory disorder of the skin and underlying tissues, including the muscles. A bluishred skin eruption occurs on the face, scalp, neck, shoulders, and knuckles and is later accompanied by severe swelling. The condition is one of the connective-tissue diseases; it is often associated with internal cancer in adults, though not in children.

Back  -    New Search

dermatophyte (der-m-toh-fyt) n.

any fungus belonging to the genera Microsporum, Epidermophyton, or Trichophyton, which cause ringworm. See also TINEA.

Back  -    New Search

dermatosis (der-m-toh-sis) n.

any disease of skin, particularly one without inflammation. juvenile plantar d. a condition in which the skin on the front of the sole becomes red, glazed, and symmetrically cracked. It affects children up to the age of 14 and is believed to be related to the wearing of trainers.

Back  -    New Search

dermis (corium) (der-mis) n.

the true skin: the thick layer of living tissue that lies beneath the epidermis.
—dermal adj.

Back  -    New Search

dermographism (der-moh-graf-izm) n.

a local reaction caused by pressure on the skin. People with such highly sensitive skin can ‘write’ on it with a finger or blunt instrument, the pressure producing weals.

Back  -    New Search

dermoid cyst (dermoid) (der-moid) n.

a cyst containing hair, hair follicles, and sebaceous glands, usually found at sites marking the fusion of developing sections of the body in the embryo.

Back  -    New Search

Descemet's membrane (dess--mayz) n.

the membrane that forms the deepest layer of the stroma of the cornea of the eye. The endothelium lies between it and the aqueous humour. [J. Descemet (1732–1810), French anatomist]

Back  -    New Search

desensitization (dee-sen-si-ty-zay-shn) n.

1 (or hyposensitization) a method for reducing the effects of a known allergen by injecting, over a period, gradually increasing doses of the allergen, until resistance is built up. See ALLERGY.

2 a technique used in the behaviour therapy of phobic states. The thing that is feared is very gradually introduced to the patient, in conjunction with relaxation therapy, so that he is able to cope with progressively closer approximations to it.
Top

Back  -    New Search

desferrioxamine (dess-ferri-oks--meen) n.

a drug that combines with iron in body tissues and fluids and is administered by mouth, injection, or as eye drops to treat iron poisoning or diseases that involve iron storage in parts of the body (see HAEMOCHROMATOSIS). Trade name: Desferal .

Back  -    New Search

desipramine (dess-ip-r-meen) n.

a tricyclic antidepressant drug administered by mouth or injection. Trade name: Pertofran .

Back  -    New Search

desmoid tumour (dez-moid) n.

a dense connective-tissue tumour with a dangerous propensity for repeated local recurrence after treatment. Intra-abdominal desmoids have an association with familial adenomatous polyposis.

Back  -    New Search

desmopressin (dess-moh-press-in) n.

a synthetic derivative of vasopressin that causes a decrease in urine output. It is taken intranasally to treat diabetes insipidus, and intravenously to treat haemophilia and von Willebrand's disease. Trade name: DDAVP .

Back  -    New Search

desogestrel (dess-oh-jee-strl) n.

a progestogen used in various oral contraceptives, usually in combination with an oestrogen. Trade names: Marvelon , Mercilon .

Back  -    New Search

desoximethasone (dess-oxi-meth--zohn) n.

a corticosteroid applied to the skin as a cream or ointment to reduce inflammation and pruritus. Trade name: Stiedex .

Back  -    New Search

desquamation (des-kw-may-shn) n.

the process in which the outer layer of the epidermis of the skin is removed by scaling.

Back  -    New Search

detached retina (di-tacht) n.

see RETINAL DETACHMENT.

Back  -    New Search

detergent (di-ter-jnt) n.

a synthetic cleansing agent that removes all impurities from a surface by reacting with grease and suspended particles, including bacteria and other microorganisms.

Back  -    New Search

detoxication (detoxification) (dee-toksi-kay-shn) n.

1 the process by which toxic substances are removed or toxic effects neutralized. It is one of the functions of the liver.

2 the ‘drying-out’ of a patient suffering from alcoholism.
Top

Back  -    New Search

detrition (di-trish-n) n.

the process of wearing away solid bodies (e.g. bones) by friction or use.

Back  -    New Search

detritus (di-try-ts) n.

particles of matter produced by disintegration, tissue death, etc.

Back  -    New Search

detrusor muscle (di-troo-ser) n.

a band of smooth muscle fibres that form the outer muscular coat of the urinary bladder and are attached to the pubis.

Back  -    New Search

Dettol (det-ol) n.

see CHLOROXYLENOL.

Back  -    New Search

detumescence (dee-tew-mes-ns) n.

1 the reverse of erection, whereby the erect penis or clitoris becomes flaccid after orgasm.

2 subsidence of a swelling.
Top

Back  -    New Search

deut- (deuto-, deuter(o)-) prefix

denoting two, second, or secondary.

Back  -    New Search

deuteranopia (dew-ter--noh-pi) n.

a defect in colour vision in which reds, yellows, and greens are confused. Compare TRITANOPIA.

Back  -    New Search

developmental delay (di-vel-p-men-t'l) n.

considerable delay in the physical or mental development of children when compared with their peers. There are many causes. Global delay describes the state of a child whose overall development is slow in all areas.

Back  -    New Search

developmental disorder n.

any one of a group of conditions that arise in infancy or childhood and are characterized by delays in biologically determined psychological functions, such as language. In pervasive conditions (e.g. autism) many types of development are involved; in specific disorders, (such as dyslexia) the handicap is an isolated problem.

Back  -    New Search

deviation (dee-vi-ay-shn) n.

1 (in ophthalmology) any abnormal position of one or both eyes. Deviations of both eyes may occur in brain disease. Deviations of one eye come into the category of squint (see STRABISMUS). dissociated vertical d. an acquired condition, chiefly associated with infantile esotropia (convergent strabismus), in which one eye looks upwards when it is covered.

2 see SEXUAL DEVIATION.
Top

Back  -    New Search

Devic's disease (dev-iks) n.

see NEUROMYELITIS OPTICA. [E. Devic (1869–1930), French physician]

Back  -    New Search

DEXA n.

dual-energy X-ray absorptiometry: a method of measuring bone density based on the proportion of a beam of photons that passes through the bone.

Back  -    New Search

dexamethasone (deks--meth--zohn) n.

a corticosteroid drug administered by mouth or injection principally to treat severe allergies, skin and eye diseases, rheumatic and other inflammatory conditions, and hormone and blood disorders. Trade names: Decadron , Maxidex .

Back  -    New Search

dexamphetamine (deks-am-fet-min) n.

a drug with actions and effects similar to those of amphetamine. Trade name: Dexedrine .

Back  -    New Search

dextr- (dextro-) prefix

denoting 1 the right side.

2 (in chemistry) dextrorotation.
Top

Back  -    New Search

dextran (deks-tran) n.

a carbohydrate, consisting of branched chains of glucose units, that is a storage product of bacteria and yeasts. Preparations of dextran solution are used in transfusions, in order to increase the volume of plasma.

Back  -    New Search

dextrin (deks-trin) n.

a carbohydrate formed as an intermediate product in the digestion of starch by the enzyme amylase. Dextrin is used in the preparation of pharmaceutical products and surgical dressings.

Back  -    New Search

dextrocardia (deks-troh-kar-di) n.

a congenital defect in which the position of the heart is a mirror image of its normal position, with the apex of the ventricles pointing to the right.

Back  -    New Search

dextromoramide (deks-troh-mor--myd) n.

an analgesic administered by mouth, injection, or as suppositories to relieve moderate or severe pain. Dextromoramide is similar to morphine and can cause morphine-type dependence. Trade name: Palfium .

Back  -    New Search

dextropropoxyphene (deks-troh-pr-poks-i-feen) n.

an analgesic administered by mouth to relieve mild or moderate pain. Trade name: Doxolene .

Back  -    New Search

dextrose (deks-trohz) n.

see GLUCOSE.

Back  -    New Search

dhobie itch (doh-bi) n.

a fungal infection of the skin that chiefly affects the groin but may spread to the thighs and buttocks. It is caused by certain species of Trichophyton and Epidermophyton. Medical name: tinea cruris . See also TINEA.

Back  -    New Search

DI n.

see ARTIFICIAL INSEMINATION.

Back  -    New Search

di- prefix

denoting two or double.

Back  -    New Search

dia- prefix

denoting 1 through.

2 completely or throughout.
Top

3 apart.
Top

Back  -    New Search

diabetes (dy--bee-teez) n.

any disorder of metabolism causing excessive thirst and the production of large volumes of urine. d. insipidus a rare form of diabetes that is due to deficiency of the pituitary hormone vasopressin. d. mellitus a disorder of carbohydrate metabolism in which sugars in the body are not oxidized to produce energy due to lack of the pancreatic hormone insulin. The accumulation of sugar leads to its appearance in the blood (hyperglycaemia), then in the urine; symptoms include thirst, loss of weight, and the excessive production of urine. The use of fats as an alternative source of energy leads to disturbances of the acid-base balance, ketosis, and eventually to convulsions preceding diabetic coma . In Type I (or insulin-dependent ) d. mellitus , which usually starts in childhood or adolescence, patients are entirely dependent on injections of insulin for survival. In Type II (or noninsulin-dependent ) d. mellitus , usually occurring after the age of 40, the pancreas retains some ability to produce insulin but this is inadequate for the body's needs (see ORAL HYPOGLYCAEMIC DRUG). In both types the diet must be controlled, with adequate carbohydrate for the body's needs. Lack of balance in the diet or in the amount of insulin taken leads to hypoglycaemia.
—diabetic (dy--bet-ik) adj., n.

Back  -    New Search

diabetic retinopathy n.

see RETINOPATHY.

Back  -    New Search

diagnosis (dy-g-noh-sis) n.

the process of determining the nature of a disorder by considering the patient's signs and symptoms, medical background, and – when necessary – results of laboratory tests and X-ray examinations. differential d. diagnosis of a condition whose signs and/or symptoms are shared by various other conditions. See also PRENATAL DIAGNOSIS. Compare PROGNOSIS.
—diagnostic (dy-g-noss-tik) adj.

Back  -    New Search

dialyser (dy--ly-zer) n.

a piece of apparatus for separating components of a liquid mixture by dialysis, especially an artificial kidney (see HAEMODIALYSIS).

Back  -    New Search

dialysis (dy-al-i-sis) n.

a method of separating particles of different dimensions in a liquid mixture, using a thin semipermeable membrane. A solution of the mixture is separated from distilled water by the membrane; the solutes pass through the membrane into the water while the proteins, etc., are retained. The principle of dialysis is used in the artificial kidney (see HAEMODIALYSIS). peritoneal d. the use of the peritoneum as a semipermeable membrane, employed when haemodialysis is not appropriate.

Back  -    New Search

diamorphine (dy--mor-feen) n.

a pharmaceutical preparation of heroin: a powerful narcotic analgesic used for the relief of severe pain.

Back  -    New Search

diapedesis (dy--p-dee-sis) n.

migration of cells through the walls of blood capillaries into the tissue spaces. Diapedesis is an important part of the reaction of tissues to injury (see INFLAMMATION).

Back  -    New Search

diaphoresis (dy--fer-ee-sis) n.

the process of sweating, especially excessive sweating. See SWEAT.

Back  -    New Search

diaphoretic (sudorific) (dy--fer-et-ik) n.

a drug, such as pilocarpine, that causes an increase in sweating. Antipyretic drugs also have diaphoretic activity.

Back  -    New Search

diaphragm (dy--fram) n.

1 (in anatomy) a thin musculomembranous dome-shaped muscle that separates the thoracic and abdominal cavities. It plays an important role in breathing. There are openings in the diaphragm through which the oesophagus, blood vessels, and nerves pass.

2 a hemispherical rubber cap fitted inside the vagina over the neck (cervix) of the uterus as a contraceptive. When combined with the use of a chemical spermicide the diaphragm provides reasonably reliable contraception.
Top

Back  -    New Search

diaphysis (dy-af-i-sis) n.

the shaft (central part) of a long bone. Compare EPIPHYSIS.

Back  -    New Search

diarrhoea (dy--ree-) n.

frequent bowel evacuation or the passage of abnormally soft or liquid faeces. Its causes include intestinal infections, other forms of intestinal inflammation, anxiety, and the irritable bowel syndrome. Severe or prolonged diarrhoea may lead to excess losses of fluid, salts, and nutrients in the faeces.

Back  -    New Search

diarthrosis (synovial joint) (dy-arth-roh-sis) n.

a freely movable joint. The ends of the adjoining bones are covered with a thin cartilaginous sheet, and the bones are linked by a ligament lined with synovial membrane, which secretes synovial fluid. See illustration.

Back  -    New Search

diastase (dy--stayz) n.

an enzyme that hydrolyses starch in barley grain to produce maltose during the malting process. It has been used to aid the digestion of starch in some digestive disorders.

Back  -    New Search

diastasis (dy-ast--sis) n.

dislocation of bones at an immovable or slightly movable joint, as at the pubic symphysis.

Back  -    New Search

diastema (dy--stee-m) n.

a space between two teeth.

Back  -    New Search

diastole (dy-ast--li) n.

the period between two contractions of the heart, when the muscle of the heart relaxes and allows the chambers to fill with blood. See also BLOOD PRESSURE, SYSTOLE.
—diastolic (dy--stol-ik) adj.

Back  -    New Search

diastolic pressure n.

see BLOOD PRESSURE.

Back  -    New Search

diathermy (dy--therm-i) n.

the production of heat in a part of the body by means of a high-frequency electric current passed between two electrodes placed on the patient's skin. The heat generated can be used in the treatment of deep-seated pain in rheumatic and arthritic conditions. d. knife a knife generating heat that coagulates blood and is used to make bloodless surgical incisions. d. snare (or needle ) an electrically heated snare (or needle) used to destroy unwanted tissue and to remove small superficial neoplasms. See also ELECTROSURGERY.

Back  -    New Search

diathesis (dy-ath-i-sis) n.

a higher than average tendency to acquire certain diseases, such as allergies, rheumatic diseases, or gout. Such diseases may run in families, but they are not inherited.

Back  -    New Search

diazepam (dy-az--pam) n.

a long-acting benzodiazepine, administered by mouth or injection, used to treat acute anxiety, delirium tremens, epilepsy, and muscle spasms. It is also used as a premedication. Trade names: Diazemuls , Valium .

Back  -    New Search

diazoxide (dy--zok-syd) n.

a drug used to lower blood pressure in patients with hypertension and also used to treat conditions in which the levels of blood sugar are low. It is administered by mouth or (for hypertension) injection. Trade name: Eudemine .

Back  -    New Search

DIC n.

see DISSEMINATED INTRAVASCULAR COAGULATION.

Back  -    New Search

dicephalus (dy-sef--ls) n.

see CRANIOPAGUS.

Back  -    New Search

dichlorphenamide (dy-klor-fen--myd) n.

a diuretic administered by mouth to reduce pressure within the eye in the treatment of glaucoma. Trade name: Daranide .

Back  -    New Search

dichromatic (dy-kroh-mat-ik) adj.

describing the state of colour vision of those who can appreciate only two of the three primary colours. Compare TRICHROMATIC.

Back  -    New Search

Dick test (dik) n.

a test for susceptibility to scarlet fever. [G. F. Dick (1881–1967) and G. R. H. Dick (1881–1963), US physicians]

Back  -    New Search

diclofenac (dy-kloh-fen-ak) n.

an anti-inflammatory drug (see NSAID) used to relieve joint pain in osteoarthritis, rheumatoid arthritis, and ankylosing spondylitis. It is administered by mouth. Trade names: Volraman , Voltarol .

Back  -    New Search

dicophane (dy-koh-fayn) n.

see DDT.

Back  -    New Search

dicrotism (dy-kr-tizm) n.

a condition in which the pulse is felt as a double beat for each contraction of the heart. It may be seen in typhoid fever.
—dicrotic (dy-krot-ik) adj.

Back  -    New Search

dicyclomine (dy-sy-kl-meen) n.

a drug that reduces spasms of smooth muscle and is administered by mouth to relieve peptic ulcer, infantile colic, colitis, and related conditions. Trade name: Merbentyl .

Back  -    New Search

didanosine (ddl) (dy-dan--seen) n.

an antiviral drug that is administered by mouth to prolong the lives of AIDS patients. Possible side-effects include damage to nerves, severe pancreatitis, nausea, vomiting, and headache.

Back  -    New Search

didym- (didymo-) prefix

denoting the testis.

Back  -    New Search

dienoestrol (dy-in-ee-strol) n.

a synthetic female sex hormone (see OESTROGEN) administered topically in the form of a vaginal cream to relieve atrophy, itching, or inflammation of the vagina as part of hormone replacement therapy. Trade name: Ortho Dienoestrol .

Back  -    New Search

diet (dy-t) n.

the mixture of foods that a person eats. balanced d. a diet that contains the correct proportions of all the nutrients.

Back  -    New Search

dietary fibre (roughage) (dy-it-er-i) n.

the part of food that cannot be digested and absorbed to produce energy. Foods with a high fibre content include whole-meal cereals and flour, root vegetables, nuts, and fruit. Dietary fibre is considered by some to be helpful in the prevention of such diseases as diverticulosis, constipation, appendicitis, obesity, and diabetes mellitus.

Back  -    New Search

dietetics (dy-i-tet-iks) n.

the application of the principles of nutrition to the selection of food and the feeding of individuals and groups.

Back  -    New Search

diethylcarbamazine (dy-eth-yl-kar-bam--zeen) n.

an anthelmintic drug that is administered by mouth in the treatment of filariasis, loiasis, and onchocerciasis.

Back  -    New Search

diethylpropion (dy-eth-yl-proh-pi-on) n.

a drug, similar to amphetamine, that suppresses the appetite and is administered by mouth in the treatment of obesity. Dependence of the amphetamine type can occur. Trade names: Apesate , Tenuate Dospan .

Back  -    New Search

Dietl's crisis (dee-t'lz) n.

acute obstruction of a kidney causing severe pain in the loins. The obstruction usually occurs at the junction of the renal pelvis and the ureter, causing the kidney to become distended with accumulated urine (see HYDRONEPHROSIS). [J. Dietl (1804–78), Polish physician]

Back  -    New Search

differential diagnosis (dif-er-en-shl) n.

see DIAGNOSIS.

Back  -    New Search

differential leucocyte count (differential blood count) n.

a determination of the proportions of the different kinds of white cells (leucocytes) present in a sample of blood. The information often aids diagnosis of disease.

Back  -    New Search

differentiation (dif-er-en-shi-ay-shn) n.

1 (in embryology) the process in embryonic development during which unspecialized cells or tissues become specialized for particular functions.

2 (in oncology) the degree of similarity of tumour cells to the structure of the organ from which the tumour arose. Tumours are classified as well, moderately, or poorly differentiated.
Top

Back  -    New Search

diffusion (di-few-zhn) n.

the mixing of one liquid or gas with another by the random movement of their particles.

Back  -    New Search

diflunisal (dy-floo-ni-sal) n.

an antiinflammatory drug (see NSAID) derived from salicylic acid and used to control symptoms in osteoarthritis and other painful conditions. It is administered by mouth. Trade name: Dolobid .

Back  -    New Search

di George syndrome (dee-jorj) n.

a hereditary condition resulting in an inability to fight infections (immuno-deficiency) associated with absence of the parathyroid and thymus glands, abnormalities of the heart, and low levels of calcium. [A. M. di George (1921– ), US paediatrician]

Back  -    New Search

digestion (dy-jes-chn) n.

the process in which ingested food is broken down in the alimentary canal into a form that can be absorbed and assimilated by the tissues of the body.

Back  -    New Search

digit (dij-it) n.

a finger or toe.

Back  -    New Search

digital (dij-it-l) adj.

1 (in anatomy) relating to a digit.

2 (in radiology) relating to or utilizing digitization. d. radiography see RADIOGRAPHY. d. subtraction angiography see ANGIOGRAPHY.
Top

Back  -    New Search

digitalis (dij-i-tay-lis) n.

an extract from the dried leaves of foxgloves (Digitalis species), which contains various substances, including digitoxin and digoxin, that stimulate heart muscle. Used to treat heart failure, it is administered by mouth or, in emergency, by injection. See also DIGITALIZATION.

Back  -    New Search

digitalization (dij-it--ly-zay-shn) n.

the administration of the drug digitalis or one of its purified derivatives to a patient with heart failure until the optimum level has been reached in the heart tissues.

Back  -    New Search

digitization (dij-it-l-zay-shn) n.

(in radiology) the representation of images produced by X-ray machines, CT scanners, MRI scanners, or ultrasound probes as a set of numerical values, which enables their electronic manipulation, storage, and transfer via computer links.

Back  -    New Search

digitoxin (dij-i-toks-in) n.

a drug that increases heart muscle contraction and is administered by mouth or injection in heart failure. It is slow-acting but the effects are prolonged.

Back  -    New Search

digoxin (dy-goks-in) n.

a drug that increases heart muscle contraction and is administered by mouth or injection in heart failure. It is rapidly effective and the effects are short-lived. Trade name: Lanoxin .

Back  -    New Search

dihydrocodeine (dy-hy-dr-koh-deen) n.

a drug administered by mouth or injection to relieve pain and suppress coughs (see ANALGESIC, ANTITUSSIVE). Trade name: DHC Continus .

Back  -    New Search

dilatation (dy-l-tay-shn) n.

the enlargement or expansion of a hollow organ (such as a blood vessel) or cavity.

Back  -    New Search

dilatation and curettage (D and C) n.

an operation in which the cervix (neck) of the uterus is dilated, using a dilator, and the lining (endometrium) of the uterus is lightly scraped off with a curette (see CURETTAGE). It is performed for a variety of reasons, including removal of cysts or tumours and examination of the endometrium in the diagnosis of gynaecological disorders.

Back  -    New Search

dilator (dy-lay-ter) n.

1 an instrument used to enlarge a body opening or cavity.

2 a drug, applied either locally or systemically, that causes expansion of a structure. See also VASODILATOR.
Top

3 a muscle that, by its action, opens an aperture or orifice in the body.
Top

Back  -    New Search

dill water (dil) n.

a preparation containing a volatile oil extracted from the dill plant (Anethum graveolens), used to treat flatulence in infants.

Back  -    New Search

diltiazem (dil-ti--zem) n.

a calcium antagonist that is used in the treatment of effort-associated angina and high blood pressure (hypertension). It acts as a vasodilator and is administered by mouth. Trade names: Britiazem , Tildiem .

Back  -    New Search

dimenhydrinate (dy-men-hy-dri-nayt) n.

an antihistamine administered by mouth or injection to prevent and treat motion sickness, nausea and vomiting due to other causes, vertigo, and inner ear disturbances. Trade name: Dramamine .

Back  -    New Search

dimercaprol (dy-mer-kap-rol) n.

a drug that combines with metals in the body and is administered by injection to treat poisoning by antimony, arsenic, bismuth, gold, mercury, and thallium and in Wilson's disease. Trade name: British Anti-Lewisite (BAL ).

Back  -    New Search

dimethicone (dy-meth-i-kohn) n.

a silicone preparation used externally to prevent undue drying of the skin and to protect it against irritating external agents. It is commonly used to prevent napkin rash in babies. Trade names: Conotrane , Siopel .

Back  -    New Search

dimethindine maleate (dy-meth-in-deen mal-i-ayt) n.

an antihistamine drug used to treat hay fever, urticaria, and other allergic conditions. It is administered by mouth. Trade names: Fenostil Retard , Vibrocil .

Back  -    New Search

dinoprost (dy-noh-prost) n.

a prostaglandin drug used to terminate pregnancy or to expel a fetus that has died. It is administered by mouth or as a vaginal tablet or gel. Trade name: Prostin F2 alpha .

Back  -    New Search

dioctyl sodium sulphosuccinate (dy-ok-tyl soh-di-m sul-foh-suk-si-nayt) n.

a softening agent that is given by mouth or in suppositories, often together with a laxative, to relieve constipation. It is also used in solution to soften ear wax.

Back  -    New Search

diode laser (dy-ohd) n.

see LASER.

Back  -    New Search

dioptre (dy-op-ter) n.

the unit of measurement of the power of refraction of a lens. One dioptre is the power of a lens that brings parallel light rays to a focus at a point one metre from the lens, after passing through it.

Back  -    New Search

diphenhydramine (dy-fen-hy-dr-meen) n.

an antihistamine with sedative properties administered by mouth or injection to treat allergic conditions, such as hay fever and rhinitis, and – in combination with other drugs – in cough mixtures.

Back  -    New Search

diphenoxylate (dy-fen-oks-i-layt) n.

a drug that is administered by mouth, often in combination with atropine (in Lomotil ), to treat diarrhoea. It is also used after colostomy or ileostomy to reduce the frequency and fluidity of the stools.

Back  -    New Search

diphosphonate (dy-fos-f-nayt) n.

any of a class of compounds that bind strongly to bone. This property makes them useful in imaging the skeleton and treating certain bone disorders, such as Paget's disease of bone.

Back  -    New Search

diphtheria (dif-theer-i) n.

an acute highly contagious infection, caused by the bacterium Corynebacterium diphtheriae, that generally affects the throat but occasionally affects other mucous membranes and the skin. Early symptoms are a sore throat, weakness, and mild fever; later, a soft grey membrane forms across the throat, constricting the air passages and causing difficulty in breathing and swallowing. Bacteria multiply at the site of infection and release a toxin into the bloodstream, which damages heart and nerves. An effective immunization programme has now made diphtheria rare in most Western countries (see also SCHICK TEST).

Back  -    New Search

diphtheroid (dif-ther-oid) adj.

resembling diphtheria (especially the membrane formed in diphtheria) or the bacteria that cause it.

Back  -    New Search

diphyllobothriasis (dy-fil-oh-bo-thry--sis) n.

an infestation of the intestine with the broad tapeworm, Diphyllobothrium latum, which sometimes causes nausea, malnutrition, diarrhoea, and anaemia resulting from impaired absorption of vitamin B_12 through the gut.

Back  -    New Search

dipipanone (dy-pip--nohn) n.

a potent analgesic drug administered by mouth or injection to relieve severe pain. Trade name: Diconal .

Back  -    New Search

dipl- (diplo-) prefix

denoting double.

Back  -    New Search

diplacusis (dip-l-kew-sis) n.

perception of a single sound as double owing to a defect of the cochlea in the inner ear.

Back  -    New Search

diplegia (dy-plee-j) n.

paralysis involving both sides of the body and affecting the legs more severely than the arms. cerebral d. a form of cerebral palsy in which there is widespread damage, in both cerebral hemispheres, of the brain cells that control the movements of the limbs.
—diplegic adj.

Back  -    New Search

diplococcus (dip-loh-kok-s) n.

any of a group of nonmotile parasitic spherical bacteria that occur in pairs. The group includes the pneumococcus.

Back  -    New Search

diploë (dip-loh-ee) n.

the lattice-like tissue that lies between the inner and outer layers of the skull.

Back  -    New Search

diploid (dip-loid) adj.

describing cells, nuclei, or organisms in which each chromosome except the Y sex chromosome is represented twice. Compare HAPLOID.
—diploid n.

Back  -    New Search

diplopia (di-ploh-pi) n.

double vision: the simultaneous awareness of two images of the one object. It is usually due to limitation of movement of one eye, which may be caused by a defect of the nerves or muscles controlling eye movement or a mechanical restriction of eyeball movement in the orbit. Double vision that does not disappear on covering one eye can be caused by early cataract (see also POLYOPIA).

Back  -    New Search

dipsomania (dip-s-may-ni) n.

morbid and insatiable craving for alcohol, occurring in paroxysms. Only a small proportion of alcoholics show this symptom. See ALCOHOLISM.

Back  -    New Search

dipyridamole (dy-py-rid--mohl) n.

a drug that dilates the blood vessels of the heart and reduces platelet aggregation. It is given by mouth or injection to prevent thrombosis around prosthetic heart valves. Trade name: Persantin .

Back  -    New Search

director (di-rek-ter) n.

an instrument used to guide the extent and direction of a surgical incision.

Back  -    New Search

dis- prefix

denoting separation.

Back  -    New Search

disability (dis--bil-iti) n.

a loss or restriction of functional ability or activity as a result of impairment of the body or mind. See also HANDICAP.

Back  -    New Search

Disabled Living Foundation (dis-ay-bld) n.

(in Britain) a voluntary agency interested in all aspects of the care of those with disabilities and in improving their quality of life.

Back  -    New Search

disaccharide (dy-sak--ryd) n.

a carbohydrate consisting of two linked monosaccharide units. The most common disaccharides are maltose, lactose, and sucrose.

Back  -    New Search

disarticulation (dis-ar-tik-yoo-lay-shn) n.

separation of two bones at a joint. This may be the result of an injury or it may be done by the surgeon at operation in the course of amputation.

Back  -    New Search

disc (disk) n.

(in anatomy) a rounded flattened structure, such as an intervertebral disc or the optic disc.

Back  -    New Search

discharge rate (dis-charj) n.

the number of cases of a specified disease or condition discharged from hospitals related to the population of the catchment area: usually expressed regionally per 10,000.

Back  -    New Search

discission (dis-sizh-n) n.

an obsolete operation for cataract in which the lens capsule was ruptured by a fine knife or needle to allow the substance of the lens to be absorbed naturally into the surrounding fluid of the eye.

Back  -    New Search

discoid lupus erythematosus (DLE) (dis-koid) n.

see LUPUS (ERYTHEMATOSUS).

Back  -    New Search

discrete (dis-kreet) adj.

composed of several parts: describing lesions that are separate and do not run into each other.

Back  -    New Search

disease (di-zeez) n.

a disorder with a specific cause and recognizable signs and symptoms; any bodily abnormality or failure to function properly, except that resulting directly from physical injury (the latter, however, may open the way for disease).

Back  -    New Search

disimpaction (dis-im-pak-shn) n.

the process of separating the broken ends of a bone when they have been forcibly driven together during a fracture.

Back  -    New Search

disinfectant (dis-in-fek-tnt) n.

an agent that destroys or removes bacteria and other microorganisms and is used to cleanse surgical instruments and other objects. Examples are cresol, hexachlorophane, and phenol.

Back  -    New Search

disinfection (dis-in-fek-shn) n.

the process of eliminating infective microorganisms from contaminated instruments, clothing, or surroundings by the use of physical means or chemicals (disinfectants).

Back  -    New Search

disinfestation (dis-in-fes-tay-shn) n.

the destruction of insect pests and other animal parasites. This generally involves the use of insecticides.

Back  -    New Search

dislocation (luxation) (dis-l-kay-shn) n.

displacement from their normal position of bones meeting at a joint such that there is complete loss of contact of the joint surfaces. The bones are restored to their normal positions by manipulation under local or general anaesthesia (see REDUCTION). Compare SUBLUXATION.

Back  -    New Search

disopyramide (dy-soh-py-r-myd) n.

a parasympatholytic drug administered by mouth to treat various heart conditions involving abnormal heart rates. Trade names: Dirythmin SA , Rythmodan .

Back  -    New Search

disorientation (dis-or-i-n-tay-shn) n.

the state produced by loss of awareness of space, time, or personality. It can occur as the result of drugs, anxiety, or organic disease (such as dementia or Korsakoff's syndrome).

Back  -    New Search

dispensary (dis-pen-ser-i) n.

a place where medicines are made up by a pharmacist according to the doctor's prescription and dispensed to patients.

Back  -    New Search

dispensing practice (dis-pen-sing prak-tis) n.

(in Britain) a general practice (usually in a remote area) in which doctors receive special allowances under the terms of the National Health Service for dispensing the medications they prescribe for their patients.

Back  -    New Search

dissection (dis-sek-shn) n.

the cutting apart and separation of the body tissues along the natural divisions of the organs and different tissues in the course of an operation. Dissection of corpses is carried out for the study of anatomy.

Back  -    New Search

disseminated (dis-sem-in-ayt-id) adj.

widely distributed in an organ (or organs) or in the whole body. The term may refer to disease organisms or to pathological changes.

Back  -    New Search

disseminated intravascular coagulation (DIC) n.

a condition resulting from overstimulation of the blood-clotting mechanisms in response to disease or injury, such as severe infection, asphyxia, hypothermia, abruptio placentae, or intrauterine fetal death. The overstimulation results in generalized blood coagulation and excessive consumption of coagulation factors. The resulting deficiency of these may lead to spontaneous bleeding.

Back  -    New Search

disseminated sclerosis n.

see MULTIPLE SCLEROSIS.

Back  -    New Search

dissociation (dis-soh-si-ay-shn) n.

(in psychiatry) the process whereby thoughts and ideas can be split off from consciousness and may function independently, allowing conflicting opinions to be held at the same time about the same object. Dissociation may be the main factor in cases of dissociative fugue and multiple personalities (see DISSOCIATIVE DISORDER).
—dissociative (dis-soh-sh-tiv) adj.

Back  -    New Search

dissociative disorder n.

any one of a group of extreme defence mechanisms that include amnesia, fugue, multiple personality disorder, and trancelike states with severely reduced response to external stimuli. See also DISSOCIATION.

Back  -    New Search

distal (dis-t'l) adj.

(in anatomy) situated away from the origin or point of attachment or from the median line of the body. Compare PROXIMAL.

Back  -    New Search

Distalgesic (dis-t'l-jee-sik) n.

see CO-PROXAMOL.

Back  -    New Search

distichiasis (dis-ti-ky--sis) n.

a very rare condition in which there is an extra row of eyelashes behind the normal row. They may rub on the cornea.

Back  -    New Search

distigmine (dy-stig-meen) n.

an anti-cholinesterase drug used to treat myasthenia gravis. It is administered by mouth. Trade name: Ubretid .

Back  -    New Search

distraction (dis-trak-shn) n.

(in orthopaedics) increasing the distance between two joint surfaces or the two ends of a divided bone.

Back  -    New Search

district nurse (home nurse) (dis-trikt) n.

(in Britain) a nurse with special training in domiciliary services. District nurses are usually employed by a community trust but may also be allocated to a designated general practice (see ATTACHMENT).

Back  -    New Search

disulfiram (dy-sul-fi-ram) n.

a drug administered by mouth in the treatment of chronic alcoholism. It acts as a deterrent by producing unpleasant effects, such as headache, nausea, and vomiting, when taken with alcohol. Trade name: Antabuse .

Back  -    New Search

dithranol (dith-r-nol) n.

a drug applied to the skin as an ointment or paste to treat psoriasis. It may irritate the skin on application. Trade names: Alphodith , Dithrolan .

Back  -    New Search

diuresis (dy-yoor-ee-sis) n.

increased secretion of urine by the kidneys. This normally follows the drinking of more fluid than the body requires, but it can be stimulated by the administration of a diuretic.

Back  -    New Search

diuretic (dy-yoor-et-ik) n.

a drug that increases the volume of urine produced by promoting the excretion of salts and water from the kidney. Diuretics are used in the treatment of oedema, high blood pressure, and glaucoma. loop d. a diuretic, such as frusemide, that acts by inhibiting reabsorption of sodium and potassium in Henle's loop. potassium-sparing d. a diuretic, such as amiloride, that prevents excessive loss of potassium at the distal convoluted tubules. thiazide d. a diuretic, such as chlorothiazide, that acts by preventing the reabsorption of sodium and potassium in the distal kidney tubules.

Back  -    New Search

diurnal (dy-ern-l) adj.

occurring during the day.

Back  -    New Search

divarication (dy-va-ri-kay-shn) n.

the separation or stretching of bodily structures. rectus d. stretching of the rectus abdominis muscle, a common condition associated with pregnancy or obesity.

Back  -    New Search

divaricator (dy-va-ri-kay-ter) n.

1 a scissor-like surgical instrument used to divide portions of tissue into two separate parts during an operation.

2 a form of retractor used to open out the sides of an abdominal incision and facilitate access.
Top

Back  -    New Search

divergence (dy-ver-jns) n.

(in ophthalmology) movement of the eyes away from the midline. d. excess a type of divergent strabismus in which the eyes are deviated outwards more when looking in the distance than for near vision. d. insufficiency a type of convergent strabismus in which the eyes are deviated slightly inwards only when looking in the distance.

Back  -    New Search

diverticular disease (dy-ver-tik-yoo-ler) n.

a condition in which there are diverticula (see DIVERTICULUM) in the colon associated with lower abdominal pain and disturbed bowel habit. The pain is due to spasm of the muscle of the intestine and not to inflammation of the diverticula (compare DIVERTICULITIS).

Back  -    New Search

diverticulitis (dy-ver-tik-yoo-ly-tis) n.

inflammation of a diverticulum, most commonly of one or more colonic diverticula. This type of diverticulitis is caused by infection and causes lower abdominal pain with diarrhoea or constipation. A Meckel's diverticulum may sometimes become inflamed due to infection, causing symptoms similar to appendicitis. Compare DIVERTICULAR DISEASE.

Back  -    New Search

diverticulosis (dy-ver-tik-yoo-loh-sis) n.

a condition in which diverticula exist in a segment of the intestine without evidence of inflammation (compare DIVERTICULITIS).

Back  -    New Search

diverticulum (dy-ver-tik-yoo-lm) n. (pl. diverticula)

a sac or pouch formed at weak points in the walls of the alimentary tract. colonic d. a diverticulum that affects the colon. They are sometimes associated with abdominal pain or altered bowel habit (see DIVERTICULAR DISEASE, DIVERTICULITIS). jejunal d. a diverticulum that affects the small intestine. They are often multiple and may give rise to abdominal discomfort and malabsorption. Meckel's d. a diverticulum that occurs in the ileum as a congenital abnormality. It may become inflamed, mimicking appendicitis, or it may form a peptic ulcer, causing pain, bleeding, or perforation.

Back  -    New Search

division (di-vizh-n) n.

the separation of an organ or tissue into parts by surgery.

Back  -    New Search

dizygotic twins (dy-zy-got-ik) pl. n.

see TWINS.

Back  -    New Search

DLE n.

discoid lupus erythematosus: see LUPUS (ERYTHEMATOSUS).

Back  -    New Search

DMD n.

Duchenne muscular dystrophy: see MUSCULAR DYSTROPHY.

Back  -    New Search

DMSA n.

dimercaptosuccinic acid labelled with technetium-99, used as a tracer to obtain scintigrams of the kidney, by means of a gamma camera, particularly to show scarring resulting from infection and to assess the relative function of each kidney.

Back  -    New Search

DNA (deoxyribonucleic acid) n.

the genetic material of nearly all living organisms, which controls heredity and is located in the cell nucleus (see CHROMOSOME, GENE). DNA is a nucleic acid composed of two strands made up of units called nucleotides, wound around each other into a double helix. The DNA molecule can make exact copies of itself by the process of replication, thereby passing on the genetic information to the daughter cells when the cell divides.

Back  -    New Search

dobutamine (doh-bew-t-meen) n.

a sympathomimetic drug used to assist in the management of heart failure. It increases the force of contraction of the ventricles and improves the heart output and it may be given by continuous intravenous drip.

Back  -    New Search

Doctor (dok-ter) n.

1 the title given to a recipient of a higher university degree than a Master's degree. The degree Medicinae Doctor (MD) is awarded by some British universities as a research degree.

2 a courtesy title given to a qualified medical practitioner, i.e. one who has been registered by the General Medical Council.
Top

Back  -    New Search

Döderlein's bacillus (ded-er-lynz) n.

the bacterium Lactobacillus acidophilus, occurring normally in the vagina and its secretions. See LACTOBACILLUS. [A. S. G. Döderlein (1860–1941), German obstetrician and gynaecologist]

Back  -    New Search

dolich- (dolicho-) prefix

denoting long.

Back  -    New Search

dolichocephaly (doli-koh-sef-li) n.

the condition of having a relatively long skull, with a cephalic index of 75 or less.
—dolichocephalic adj.

Back  -    New Search

dolor (dol-er) n.

pain: one of the four classical signs of inflammation in a tissue. See also CALOR, RUBOR, TUMOR.

Back  -    New Search

dolorimetry (dol-er-im-itri) n.

the measurement of pain. See ALGESIMETER.

Back  -    New Search

domiciliary midwife (dom-i-sil-yeri) n.

see COMMUNITY MIDWIFE.

Back  -    New Search

domiciliary services pl. n.

(in Britain) health and social services that are available in the home and are distinguished from hospital-based services.

Back  -    New Search

dominant (dom-i-nnt) adj.

(in genetics) describing a gene (or its corresponding characteristic) whose effect is shown in the individual whether its allele is the same or different. autosomal d. see AUTOSOMAL (DOMINANT). Compare RECESSIVE.
—dominant n.

Back  -    New Search

domiphen (doh-mi-fen) n.

an antiseptic administered in the form of lozenges to treat bacterial and fungal infections of the mouth and throat. It is also used in solution for cleansing wounds, treating fungal infections of the skin, etc. Trade name: Bradosol .

Back  -    New Search

domperidone (dom-pe-ri-dohn) n.

an antiemetic drug used especially to reduce the nausea and vomiting caused by other drugs (e.g. anticancer drugs). It is administered by mouth or suppository. Trade names: Evoxin , Motilium .

Back  -    New Search

Donald-Fothergill operation (Fothergill's operation, Manchester operation) (don-ld foth-er-gil) n.

a surgical operation consisting of anterior colporrhaphy, amputation of the cervix, and colpoperineorrhaphy. It is performed for genital prolapse. [A. Donald (1860–1933) and W. E. Fothergill (1865–1926), British gynaecologists]

Back  -    New Search

donor (doh-ner) n.

a person who makes his own tissues or organs available for use by someone else. For example, a donor may provide blood for transfusion or a kidney for transplantation. d. insemination see ARTIFICIAL INSEMINATION.

Back  -    New Search

dopa (doh-p) n.

dihydroxyphenylalanine: a physiologically important compound that forms an intermediate stage in the synthesis of catecholamines from the essential amino acid tyrosine. The laevorotatory form, levodopa, is administered for the treatment of parkinsonism.

Back  -    New Search

dopamine (doh-p-meen) n.

a catecholamine derived from dopa that functions as a neurotransmitter, acting on specific dopamine receptors and also on adrenergic receptors throughout the body; it also stimulates the release of noradrenaline from nerve endings. Dopamine is used as a drug to increase the strength of contraction of the heart in heart failure, shock, severe trauma, and septicaemia. It is administered by injection in carefully controlled dosage.

Back  -    New Search

Doppler ultrasound (dop-ler) n.

a diagnostic technique that utilizes the fact that the frequency of ultrasound waves changes when they are reflected from a moving surface. It can be used to study the flow in blood vessels and the movement of such structures as heart valves. The frequency detector is contained within the ultrasound probe, which displays the anatomy on a TV screen (see also DUPLEX IMAGING). Flow, direction, and velocity can be allocated to different colours and displayed on a colour monitor (colour flow ultrasound imaging ). [C. J. Doppler (1803–53), Austrian physicist]

Back  -    New Search

dors- (dorsi-, dorso-) prefix

denoting 1 the back.

2 dorsal.
Top

Back  -    New Search

dorsal (dor-sl) adj.

relating to or situated at or close to the back of the body or to the posterior part of an organ.

Back  -    New Search

dorsiflexion (dor-si-flek-shn) n.

backward flexion of the foot or hand or their digits; i.e. bending towards the upper surface.

Back  -    New Search

dorsoventral (dor-soh-ven-trl) adj.

(in anatomy) extending from the back (dorsal) surface to the front (ventral) surface.

Back  -    New Search

dorsum (dor-sm) n.

1 the back.

2 the upper or posterior surface of a part of the body.
Top

Back  -    New Search

dose (dohs) n.

a carefully measured quantity of a drug that is prescribed by a doctor to be given to a patient at any one time.

Back  -    New Search

dosimetry (doh-sim-itri) n.

the calculation of appropriate doses for given conditions, usually the calculation of correct amounts of radiation for the treatment of cancer in different parts of the body. See RADIOTHERAPY.

Back  -    New Search

double vision (dub-l) n.

see DIPLOPIA.

Back  -    New Search

douche (doosh) n.

a forceful jet of water used for cleaning any part of the body, most commonly the vagina.

Back  -    New Search

Down's syndrome (downz) n.

a condition resulting from a genetic abnormality in which an extra chromosome is present (there are three no. 21 chromosomes instead of the usual two), giving a total of 47 chromosomes rather than the normal 46. The chances of having a Down's child are higher with increasing maternal age. Affected individuals share certain clinical features, including a characteristic flat facial appearance with slanting eyes (as in the Mongolian races, which gave the former name, mongolism , to the condition), broad hands with short fingers and a single crease across the palm, malformed ears, eyes with a speckled iris (Brushfield's spots ), and short stature. Many individuals also have a degree of mental handicap, although the range of ability is wide and some individuals are of normal intelligence. Medical name: trisomy 21 . [J. L. H. Down (1828–96), British physician]

Back  -    New Search

doxapram (doks--pram) n.

a drug that stimulates breathing and has similar effects and uses to those of nikethamide. Trade name: Dopram .

Back  -    New Search

doxazosin (doks-az-oh-sin) n.

an alpha-blocker drug used to treat high blood pressure. It is administered by mouth. Trade name: Cardura .

Back  -    New Search

doxepin (doks--pin) n.

a drug that is administered by mouth to relieve depression, especially when associated with anxiety (see ANTIDEPRESSANT, TRANQUILLIZER). Trade name: Sinequan .

Back  -    New Search

doxorubicin (doks-oh-roo-bi-sin) n.

an anthracycline antibiotic isolated from Streptomyces peucetius caesius and used mainly in the treatment of leukaemia and various other forms of cancer. It is administered by injection or infusion; side-effects include bone marrow depression, baldness, gastrointestinal disturbances, and heart damage. Trade name: Adriamycin .

Back  -    New Search

doxycycline (doks-i-sy-kleen) n.

an antibiotic administered by mouth to treat infections caused by a wide range of bacteria and other microorganisms. Trade names: Nordox , Vibramycin .

Back  -    New Search

DPT vaccine n.

a combined vaccine against diphtheria, whooping cough (pertussis), and tetanus organisms, prepared from their toxoids and other antigens. See Urine, Normal Biochemical Values for 8.

Back  -    New Search

dracontiasis (drak-on-ty--sis) n.

a tropical disease caused by the parasitic nematode Dracunculus medinensis (see GUINEA WORM). The disease is transmitted to man via contaminated drinking water. The worm migrates to the skin surface and eventually forms a large blister, usually on the legs or arms, which bursts and may ulcerate and become infected.

Back  -    New Search

Dracunculus (dra-kunk-yoo-ls) n.

see GUINEA WORM.

Back  -    New Search

dragee (dra-zhay) n.

a pill that has been coated with sugar.

Back  -    New Search

drain (drayn)

1 n. a device, usually a tube or wick, used to draw fluid from an internal body cavity to the surface. Suction can be applied through a tube drain to increase its effectiveness.

2 vb. see DRAINAGE.
Top

Back  -    New Search

drainage (drayn-ij) n.

the drawing off of fluid from a cavity in the body, usually fluid that has accumulated abnormally. See also DRAIN.

Back  -    New Search

drastic (dras-tik) n.

any agent causing a major change in a body function.

Back  -    New Search

draw-sheet (draw-sheet) n.

a sheet placed beneath a patient in bed that may be pulled under the patient when one portion has been soiled or becomes uncomfortably wrinkled.

Back  -    New Search

drepanocyte (sickle cell) (drep--noh-syt) n.

see SICKLE-CELL DISEASE.

Back  -    New Search

drepanocytosis (drep--noh-sy-toh-sis) n.

see SICKLE-CELL DISEASE.

Back  -    New Search

dressing (dres-ing) n.

material applied to a wound or diseased part of the body, with or without medication, to give protection and assist healing.

Back  -    New Search

drill (dril) n.

(in dentistry) a rotary instrument used to remove tooth substance, particularly in the treatment of caries.

Back  -    New Search

drip (intravenous drip) (drip) n.

apparatus for the continuous injection (transfusion) of blood, plasma, saline, glucose solution, or other fluid into a vein. The fluid flows under gravity from a suspended bottle through a tube ending in a hollow needle inserted into the patient's vein.

Back  -    New Search

droperidol (droh-pe-ri-dol) n.

a butyrophenone antipsychotic drug that produces a state of emotional quietness and mental detachment. It is sometimes used as a premedication before surgery. Trade name: Droleptan .

Back  -    New Search

dropsy (drop-si) n.

see OEDEMA.

Back  -    New Search

drug (drug) n.

any substance that affects the structure or functioning of a living organism. Drugs are widely used for the prevention, diagnosis, and treatment of disease and for the relief of symptoms.

Back  -    New Search

drug dependence n.

see DEPENDENCE.

Back  -    New Search

Drug Doses, Formulae for calculating

solid drugs
amount of stock = strength requiredstock strength
liquid drugs
amount of stock = strength requiredstock strength × volume of stock strength
drugs measured in units
amount of stock = no. units requiredno. units in stock strength × volume of stock strength
preparation of solutions
amount of stock = strength requiredstock strength × final total volume

children's dose(1) Clarke's body surface weight rule
child's dose = adult dose × weight of child (kg)average adult weight (70 kg)

(2) Clarke's body surface area rule
child's dose = adult dose × surface area of childsurface area of adult

drip flow rate
rate (drops/minute) = volume of solution (ml) × no. drops/mltime (minutes)

Note: macrodrop delivers 15 drops/ml

microdrop delivers 60 drops/ml

Back  -    New Search

drusen (macular drusen) (droo-sn) pl. n.

white or yellow deposits of hyalin in Bruch's membrane of the choroid. They are often associated with macular degeneration.

Back  -    New Search

dry mouth (dry) n.

a condition that occurs as a result of reduced salivary flow from a variety of causes, including Sjögren's syndrome, connective-tissue disease, diabetes, excision or absence of a major salivary gland, or radiotherapy to the head that destroys the salivary glands. Medical name: xerostomia .

Back  -    New Search

DTIC n.

see DACARBAZINE.

Back  -    New Search

DTPA n.

diethylenetriaminepentaacetic acid labelled with technetium-99, used as a tracer to obtain scintigrams of the kidney over a period of time, by means of a gamma camera, to show function and reflux.

Back  -    New Search

Duchenne muscular dystrophy (DMD) (dew-shen) n.

see MUSCULAR DYSTROPHY. [G. B. A. Duchenne (1806–75), French neurologist]

Back  -    New Search

Ducrey's bacillus (doo-krayz) n.

the bacterium Haemophilus ducreyi. See HAEMOPHILUS. [A. Ducrey (1860–1940), Italian dermatologist]

Back  -    New Search

duct (dukt) n.

a tubelike structure or channel, especially one for carrying glandular secretions.

Back  -    New Search

ductless gland (dukt-lis) n.

see ENDOCRINE GLAND.

Back  -    New Search

ductule (duk-tewl) n.

a small duct or channel.

Back  -    New Search

ductus arteriosus (duk-ts ar-teer-i-oh-ss) n.

a blood vessel in the fetus connecting the pulmonary artery directly to the ascending aorta, so bypassing the pulmonary circulation. It normally closes after birth. patent d. a. failure of the ductus to close, producing a continuous murmur and consequences similar to those of a septal defect.

Back  -    New Search

dumbness (dum-nis) n.

see MUTISM.

Back  -    New Search

Dumdum fever (dum-dum) n.

see KALAAZAR.

Back  -    New Search

dumping syndrome (dump-ing) n.

a group of symptoms that sometimes occur after stomach operations, particularly gastrectomy (postgastrectomy syndrome ). After a meal, especially one rich in carbohydrate, the patient feels faint, weak, and nauseous, has a rapid pulse, and may sweat and become pale.

Back  -    New Search

duo- prefix

denoting two.

Back  -    New Search

duoden- (duodeno-) prefix

denoting the duo

Back  -    New Search

duodenal ulcer (dew--deen-l) n.

an ulcer in the duodenum, caused by the action of acid and pepsin on the duodenal lining (mucosa) of a susceptible individual. Symptoms include pain in the upper abdomen and vomiting; complications include bleeding (see HAEMATEMESIS), perforation, and obstruction due to scarring (see PYLORIC STENOSIS). See also HELICOBACTER.

Back  -    New Search

duodenoscope (dew--deen--skohp) n.

a fibreoptic or video instrument for examining the interior of the duodenum. An end-viewing instrument is used for most examinations, but a side-viewing instrument is used for ERCP. The end-viewing instrument is also used for examination of the stomach (gastroduodenoscope ) and it is usual to combine the two examinations (gastroduodenoscopy ).

Back  -    New Search

duodenostomy (dew--di-nost-mi) n.

an operation in which the duodenum is brought through the abdominal wall and opened, usually in order to introduce food. See also GASTRODUODENOSTOMY.

Back  -    New Search

duodenum (dew--deen-m) n.

the first of the three parts of the small intestine. It extends from the pylorus of the stomach to the jejunum. The duodenum receives bile from the gall bladder and pancreatic juice from the pancreas.
—duodenal adj.

Back  -    New Search

duplex imaging (dew-pleks) n.

a method for measuring blood flow using an ultrasound source and a coupled Doppler probe (see DOPPLER ULTRASOUND). It is especially useful for estimating venous blood flow.

Back  -    New Search

Dupuytren's contracture (dew-pwee-trahnz) n.

forward curvature of the fingers (usually the ring and little fingers) caused by contracture of the fascia in the palm and fingers. [Baron G. Dupuytren (1777–1835), French surgeon]

Back  -    New Search

dura (dura mater, pachymeninx) (dewr-) n.

the thickest and outermost of the three meninges surrounding the brain and spinal cord.
—dural adj.

Back  -    New Search

DVT n.

deep vein thrombosis. See PHLEBOTHROMBOSIS.

Back  -    New Search

dwarfism (dworf-izm) n.

abnormally short stature. The most common cause is achondroplasia. Dwarfism may also be caused by a deficiency of growth hormone due to a defect in the pituitary gland; a genetic defect in the response to growth hormone; thyroid deficiency (see CRETINISM); such chronic diseases as rickets; renal failure; and intestinal malabsorption.

Back  -    New Search

dydrogesterone (dy-droh-jest-er-ohn) n.

a synthetic female sex hormone (see PROGESTOGEN) administered by mouth to treat menstrual abnormalities (such as dysmenorrhoea) and infertility and to prevent miscarriage. Trade name: Duphaston .

Back  -    New Search

dynamic splintage (dy-nam-ik splint-ij) n.

a technique that retains the essentials of splinting but allows some movement of the restrained body part.

Back  -    New Search

dynamometer (dy-n-mom-it-er) n.

a device for recording the force of a muscular contraction. A small hand-held dynamometer may be used to record the strength of a patient's grip.

Back  -    New Search

-dynia suffix

denoting pain.

Back  -    New Search

dys- prefix

denoting difficult, abnormal, or impaired.

Back  -    New Search

dysaesthesiae (dis-iss-theez-i-ee) pl. n.

the abnormal and sometimes unpleasant sensations felt by a patient with partial damage to sensory nerve fibres when his skin is stimulated. Compare PARAESTHESIAE.

Back  -    New Search

dysarthria (dis-arth-ri) n.

a speech disorder in which the pronunciation is unclear although the linguistic content and meaning are normal.

Back  -    New Search

dysbarism (dis-bar-izm) n.

any clinical syndrome due to a difference between the atmospheric pressure outside the body and the pressure outside the body and the pressure of air or gas within a body cavity. See COMPRESSED AIR ILLNESS.

Back  -    New Search

dyschezia (dis-kee-zi) n.

a form of constipation resulting from a long period of voluntary suppression of the urge to defecate. The rectum becomes distended with faeces and bowel movements are difficult or painful.

Back  -    New Search

dyschondroplasia (Ollier's disease) (dis-kon-droh-play-zi) n.

a condition due to faulty ossification of cartilage, resulting in development of many benign cartilaginous tumours (see CHONDROMA). The bones involved may become stunted and deformed and there is a risk of developing malignant tumours.

Back  -    New Search

dyschromatopsia (dis-kroh-m-top-si) n.

any defect of colour vision.

Back  -    New Search

dyscoria (dis-kor-i) n.

any abnormality in the shape of the pupil of the eye.

Back  -    New Search

dyscrasia (dis-kray-zi) n.

an abnormal state of the body or part of the body, especially one due to abnormal development or metabolism.

Back  -    New Search

dysdiadochokinesis (adiadochokinesis) (dis-dy-ad--koh-ki-nee-sis) n.

clumsiness in performing rapidly alternating movements. It is a sign of disease of the cerebellum or its intracerebral connections.

Back  -    New Search

dysentery (dis-n-tri) n.

an infection of the intestinal tract causing severe diarrhoea with blood and mucus. amoebic d. (amoebiasis) dysentery caused by the protozoan Entamoeba histolytica. It is mainly confined to tropical and subtropical countries. bacillary d. dysentery caused by bacteria of the genus Shigella. Epidemics are common in overcrowded insanitary conditions. Compare CHOLERA.

Back  -    New Search

dysfunction (dis-funk-shn) n.

impairment or abnormality in the functioning of an organ.
—dysfunctional adj.

Back  -    New Search

dysfunctional uterine bleeding (dis-funk-shn-l) n.

see MENORRHAGIA.

Back  -    New Search

dysgenesis (dis-jen-i-sis) n.

faulty development.

Back  -    New Search

dysgerminoma (germinoma, gonocytoma) (dis-jer-mi-noh-m) n.

a malignant tumour of the ovary, thought to arise from primitive germ cells; it is homologous to the seminoma of the testis. The tumours are very sensitive to radiotherapy. Dysgerminomas are also known as large cell carcinomas or alveolar sarcomas of the ovary .

Back  -    New Search

dysgraphia (dis-graf-i) n.

see AGRAPHIA.

Back  -    New Search

dyskariosis (dis-ka-ri-oh-sis) n.

the abnormal condition of a cell that has a nucleus showing the features characteristic of the earliest stage of malignancy. It may be seen, for example, in the squamous and columnar epithelial cells of a cervical smear.

Back  -    New Search

dyskinesia (dis-ki-nee-zi) n.

a group of involuntary movements, including chorea and dystonia, that appear to be a fragmentation of the normal smoothly controlled limb and facial movements.

Back  -    New Search

dyslalia (dis-lay-li) n.

a speech disorder in which the patient uses a vocabulary or range of sounds that is peculiar to him.

Back  -    New Search

dyslexia (dis-leks-ia) n.

a developmental disorder selectively affecting a child's ability to learn to read and write. The condition can create serious educational problems. It is sometimes called specific d. , developmental reading disorder , or developmental word blindness to distinguish it from acquired difficulties with reading and writing. Compare ALEXIA.
—dyslexic adj.

Back  -    New Search

dyslogia (dis-loh-ji) n.

disturbed and incoherent speech. This may be due to dementia, aphasia, mental retardation, or mental illness.

Back  -    New Search

dysmenorrhoea (dis-men--ree-) n.

painful menstruation. primary (spasmodic) d. dysmenorrhoea that begins with the first period and is heralded by cramping lower abdominal pains starting just before or with the menstrual flow and continuing during menstruation. It is often associated with nausea, vomiting, headache, faintness, and symptoms of peripheral vasodilatation. secondary (congestive) d. dysmenorrhoea that usually affects older women who complain of a congested ache with lower abdominal cramps, which usually start from a few days to two weeks before menstruation. Causes include pelvic inflammatory disease, endometriosis, fibroids, and the presence of an IUCD.

Back  -    New Search

dysostosis (dis-oss-toh-sis) n.

the abnormal formation of bone or the formation of bone in abnormal places, such as a replacement of cartilage by bone.

Back  -    New Search

dyspareunia (dis-p-roo-ni) n.

painful or difficult sexual intercourse experienced by a woman. Psychological or physical factors may be responsible (see VAGINISMUS).

Back  -    New Search

dyspepsia (indigestion) (dis-pep-si) n.

disordered digestion: usually applied to pain or discomfort in the lower chest or abdomen after eating and sometimes accompanied by nausea or vomiting.
—dyspeptic adj.

Back  -    New Search

dysphagia (dis-fay-ji) n.

a condition in which the action of swallowing is either difficult to perform, painful (see ODYNOPHAGIA), or in which swallowed material seems to be held up in its passage to the stomach.

Back  -    New Search

dysphasia (dis-fay-zi) n.

see APHASIA.

Back  -    New Search

dysphemia (dis-fee-mi) n.

see STAMMERING.

Back  -    New Search

dysphonia (dis-foh-ni) n.

difficulty in voice production. This may be due to a disorder of the larynx, pharynx, tongue, or mouth, or it may be psychogenic. Compare DYSARTHRIA, APHASIA.

Back  -    New Search

dysplasia (alloplasia, heteroplasia) (dis-play-zi) n.

abnormal development of skin, bone, or other tissues. See also BRONCHOPULMONARY (DYSPLASIA).
—dysplastic (dis-plas-tik) adj.

Back  -    New Search

dyspnoea (disp-nee-) n.

laboured or difficult breathing. Dyspnoea can be due to obstruction to the flow of air into and out of the lungs (as in bronchitis and asthma), various diseases affecting the tissue of the lung, or heart disease.

Back  -    New Search

dyspraxia (dis-praks-i) n.

see APRAXIA.

Back  -    New Search

dysrhythmia (dis-rith-mi) n.

abnormality in a rhythm, such as the rhythm of speech or of brain waves as recorded on an EEG.

Back  -    New Search

dyssocial (dis-soh-shl) adj.

describing a personality disorder characterized by callous unconcern for others, irresponsibility, violence, disregard for social rules, and an incapacity to maintain enduring relationships.

Back  -    New Search

dyssynergia (asynergia) (dis-sin-er-ji) n.

lack of coordination, especially clumsily uncoordinated movements found in patients with disease of the cerebellum.

Back  -    New Search

dysthymic disorder (dis-th'y-mik dis-or-der) n.

see DEPRESSION.

Back  -    New Search

dystocia (dis-toh-si) n.

difficult birth. It may be caused by abnormalities in the fetus (fetal d. ), such as excessive size or malpresentation, or by abnormalities in the mother (maternal d. ), such as an abnormally small pelvis or failure of the uterine muscles to contract.

Back  -    New Search

dystonia (dis-toh-ni) n.

a postural disorder often associated with disease of the basal ganglia in the brain. There may be spasm in the muscles of the face, shoulders, neck, trunk, and limbs. The arm is often held in a rotated position and the head may be drawn back and to one side.
—dystonic adj.

Back  -    New Search

dystrophia adiposogenitalis (dis-troh-fi adi-poh-soh-jen-i-tahl-iss) n.

see FRÖHLICH'S SYNDROME.

Back  -    New Search

dystrophia myotonica (myotonic dystrophy) (my--ton-ik) n.

a type of muscular dystrophy in which the muscle weakness and wasting is accompanied by an unnatural prolongation of the muscular contraction after any voluntary effort (see MYOTONIA). The disease can affect both sexes (as it is inherited as an autosomal dominant character).

Back  -    New Search

dystrophy (dystrophia) (dis-tr-fi) n.

a disorder of an organ or tissue, usually muscle, due to impaired nourishment of the affected part. See also BECKER MUSCULAR DYSTROPHY, FUCHS' ENDOTHELIAL DYSTROPHY, MUSCULAR DYSTROPHY.

Back  -    New Search

dysuria (dis-yoor-i) n.

difficult or painful urination. This is usually associated with urgency and frequency of urination if it is due to cystitis or urethritis.

Back  -    New Search

E

ear (eer) n.

the sense organ concerned with hearing and balance. Sound waves, transmitted from the outside into the external auditory meatus, cause the eardrum (tympanic membrane) to vibrate. The small bones (ossicles) of the middle ear — the malleus, incus, and stapes — transmit the sound vibrations to the fenestra ovalis, which leads to the inner ear (see LABYRINTH). Inside the cochlea the sound vibrations are converted into nerve impulses. Pressure within the ear is released through the Eustachian tube. The semicircular canals, saccule, and utricle — also in the inner ear — are all concerned with balance.

Back  -    New Search

earache (eer-ayk) n.

see OTITIS, OTALGIA.

Back  -    New Search

eardrum (eer-drum) n.

see TYMPANIC MEMBRANE.

Back  -    New Search

earwax (eer-waks) n.

see CERUMEN.

Back  -    New Search

Ebola virus (i-boh-l) n.

a virus responsible for an acute infection in humans with features similar to those of Marburg disease. Transmission is by contact with infected blood and other body fluids. The mortality rate is 53–88%, but intensive treatment (including rehydration) in the early stages of the disease can halt its rapid and usually irreversible progression to haemorrhaging of internal organs.

Back  -    New Search

Ebstein's anomaly (eb-stynz) n.

a form of congenital heart disease affecting the right side of the heart: the muscle is unusually thin and the heart valves are abnormal. It causes breathlessness and sometimes cyanosis. If mild, life expectancy is normal. If severe, corrective surgery may be necessary. [W. Ebstein (1836–1912), German physician]

Back  -    New Search

eburnation (ee-ber-nay-shn) n.

the wearing down of the cartilage at the articulating surface of a bone, exposing the underlying bone. This is an end result of osteoarthritis.

Back  -    New Search

EB virus (EBV) n.

see EPSTEIN-BARR VIRUS.

Back  -    New Search

ec- prefix

denoting out of or outside.

Back  -    New Search

ecbolic (ek-bol-ik) n.

an agent, such as oxytocin, that induces childbirth by stimulating contractions of the uterus.

Back  -    New Search

ecchondroma (ek-kon-droh-m) n. (pl. ecchondromata)

a benign cartilaginous tumour (see CHONDROMA) that protrudes beyond the margins of a bone. Compare ENCHONDROMA.

Back  -    New Search

ecchymosis (eki-moh-sis) n.

a bruise: an initially bluish-black mark on the skin, resulting from the release of blood into the tissues either through injury or through the spontaneous leaking of blood from the vessels.

Back  -    New Search

eccrine (ek-ryn) adj.

describing sweat glands that are distributed all over the body. They are densest on the soles of the feet and the palms of the hands. Compare APOCRINE.

Back  -    New Search

ecdysis (ek-dy-sis) n.

the act of shedding skin; desquamation.

Back  -    New Search

ECG n.

see ELECTROCARDIOGRAM.

Back  -    New Search

echinococciasis (echinococcosis) (i-ky-noh-k-ky--sis) n.

see HYDATID DISEASE.

Back  -    New Search

Echinococcus (i-ky-n-kok-s) n.

a genus of small parasitic tapeworms. Adults are found in the intestines of dogs, wolves, or jackals. If the eggs are swallowed by man, the resulting larvae may cause hydatid disease. Two species causing this condition are E. granulosus and E. multilocularis.

Back  -    New Search

echocardiography (ek-oh-kar-di-og-rfi) n.

the use of ultrasound waves to investigate and display the action of the heart as it beats. Used in the diagnosis and assessment of congenital and acquired heart diseases, it is safe, painless, and reliable. Doppler e. a technique for calculating blood flow and pressure within the heart and great vessels by observing the reflection of ultrasound from moving red blood cells. M-mode e. a technique using a single beam of ultrasound to produce a nonanatomical image that permits precise measurement of cardiac dimensions. real-time e. a technique using a pulsed array of ultrasound beams to build up a moving image on a TV monitor of the chambers and valves of the heart.

Back  -    New Search

echoencephalography (ek-oh-en-sef--log-rfi) n.

investigation of structures within the skull by detecting the echoes of ultrasonic pulses.

Back  -    New Search

echography (ek-og-rfi) n.

an obsolete term for ultrasound imaging. See ULTRASONOGRAPHY.

Back  -    New Search

echokinesis (ek-oh-ki-nee-sis) n.

see ECHOPRAXIA.

Back  -    New Search

echolalia (ek-oh-lay-li) n.

pathological repetition of the words spoken by another person. It may be a symptom of language disorders, autism, catatonia, or Gilles de la Tourette syndrome.

Back  -    New Search

echopraxia (echokinesis) (ek-oh-praks-i) n.

pathological imitation of the actions of another person. It may be a symptom of catatonia.

Back  -    New Search

echovirus (ek-oh-vy-rs) n.

one of a group of about 30 RNA-containing viruses originally isolated from the human intestinal tract. These viruses were termed enteric cytopathic human orphan viruses and are the cause of some neurological disorders. Compare REOVIRUS.

Back  -    New Search

eclabium (ek-lay-bim) n.

the turning outward of a lip.

Back  -    New Search

eclampsia (i-klamp-si) n.

the occurrence, in a woman with pre-eclampsia, of one or more convulsions not caused by other conditions, such as epilepsy or cerebral haemorrhage. The onset of convulsions may be preceded by a sudden rise in blood pressure and/or a sudden increase in oedema and development of oliguria. The convulsions are usually followed by coma. Eclampsia is a threat to both mother and baby and must be treated immediately.

Back  -    New Search

ecmnesia (ek-nee-zi) n.

loss of memory for recent events that does not extend to more remote ones: a common symptom of old age.

Back  -    New Search

ECMO n.

see EXTRACORPOREAL (MEMBRANE OXYGENATION).

Back  -    New Search

ECoG n.

see ELECTROCOCHLEOGRAPHY.

Back  -    New Search

ecology (bionomics) (ee-kol-ji) n.

the study of the relationships between man, plants and animals, and the environment.
—ecological adj. —ecologist n.

Back  -    New Search

econazole (ee-kon--zohl) n.

an antifungal drug used to treat ringworm and candidosis. It is administered as a cream, lotion, spray powder, or vaginal pessary. Trade names: Ecostatin , Pevaryl .

Back  -    New Search

écraseur (ay-kra-zer) n.

a surgical device, resembling a snare, that is used to sever the base of a tumour during its surgical removal.

Back  -    New Search

ecstasy (ek-st-si) n.

a sense of extreme well-being and bliss. While not necessarily pathological, it can be caused by epilepsy (especially of the temporal lobe) or by schizophrenia.

Back  -    New Search

Ecstasy n.

the street name for methylenedioxymethamphetamine (MDMA), a mildly hallucinogenic drug that generates feelings of euphoria in those who take it. Its most common side-effect is hyperthermia; drinking large quantities of water to combat the intense thirst produced by taking the drug may result in fatal damage to the body's fluid balance. Its manufacture, sale, use, and possession are illegal.

Back  -    New Search

ECT n.

see ELECTROCONVULSIVE THERAPY.

Back  -    New Search

ect- (ecto-) prefix

denoting outer or external.

Back  -    New Search

ectasia (ectasis) (ek-tay-zi) n.

the dilatation of a tube, duct, or hollow organ.

Back  -    New Search

ecthyma (ek-th'y-m) n.

an infection of the skin, usually caused by both Streptococcus pyogenes and Staphylococcus aureus, in which the full thickness of the epidermis is involved (compare IMPETIGO). Ecthyma heals slowly and causes scarring.

Back  -    New Search

ectoderm (ek-toh-derm) n.

the outer of the three germ layers of the early embryo. It gives rise to the nervous system and sense organs, the teeth and lining of the mouth, and the epidermis and its associated structures (hair, nails, etc.).
—ectodermal adj.

Back  -    New Search

ectomorphic (ek-toh-mor-fik) adj.

describing a body type that is relatively thin, with a large skin surface in comparison to weight.
—ectomorph n. —ectomorphy n.

Back  -    New Search

-ectomy suffix

denoting surgical removal of a segment or all of an organ or part.

Back  -    New Search

ectoparasite (ek-toh-pa-r-syt) n.

a parasite that lives on the outer surface of its host. Compare ENDOPARASITE.

Back  -    New Search

ectopia (ek-toh-pi) n.

1 the misplacement, due either to a congenital defect or injury, of a bodily part.

2 the occurrence of something in an unnatural location (see ECTOPIC BEAT, ECTOPIC PREGNANCY).
Top

—ectopic (ek-top-ik) adj.

Back  -    New Search

ectopic beat (extrasystole) n.

a heartbeat due to an impulse generated somewhere in the heart outside the sinoatrial node. They may be produced by any heart disease, by nicotine from smoking, or by caffeine from excessive tea or coffee consumption; they are common in normal individuals. See ARRHYTHMIA.

Back  -    New Search

ectopic pregnancy (extrauterine pregnancy) n.

the development of a fetus at a site other than in the uterus. The most common type of ectopic pregnancy occurs in Fallopian tubes that become blocked or inflamed (tubal or oviducal pregnancy ). The growth of the fetus may cause the tube to rupture and bleed. In many cases the fetus dies within three months of conception. Medical name: eccyesis .

Back  -    New Search

ectro- prefix

denoting congenital absence.

Back  -    New Search

ectrodactyly (ek-troh-dak-ti-li) n.

congenital absence of all or part of one or more fingers.

Back  -    New Search

ectromelia (ek-troh-mee-li) n.

congenital absence or gross shortening (aplasia) of the long bones of one or more limbs. See also AMELIA, HEMIMELIA, PHOCOMELIA.

Back  -    New Search

ectropion (ek-troh-pi-n) n.

turning out of the eyelid, away from the eyeball.

Back  -    New Search

eczema (eks-im) n.

a common itchy skin disease characterized by reddening (erythema) and vesicle formation, which may lead to weeping and crusting. Outside agents do not play a primary role (compare DERMATITIS), but in some contexts the terms ‘dermatitis’ and ‘eczema’ are used interchangeably. atopic e. eczema that affects up to 20% of the population and is associated with asthma and hay fever. discoid (or nummular ) e. a type of eczema that is characterized by coin-shaped lesions and occurs only in adults. gravitational (or stasis ) e. eczema associated with poor venous circulation. seborrhoeic e. eczema that involves the scalp, eyelids, nose, and lips and is associated with the presence of Pityrosporum yeasts and is common in patients with AIDS. See also POMPHOLYX.
—eczematous (eks-em--ts) adj.

Back  -    New Search

edentulous (ee-den-choo-ls) adj.

lacking teeth: usually applied to people who have lost some or all of their teeth.

Back  -    New Search

edetate (ee-di-tayt) n.

a salt of the compound ethylenediaminetetraacetic acid (EDTA), used as a chelating agent in the treatment of poisoning. dicobalt e. an antidote to cyanide, administered by intravenous injection as soon as possible after poisoning. calcium disodium e. a drug used to treat poisoning by heavy metals, such as lead and strontium.

Back  -    New Search

edrophonium (ed-roh-foh-nim) n.

a drug that stimulates the skeletal muscles (see PARASYMPATHOMIMETIC). It is administered by injection in a test for diagnosis of myasthenia gravis. Trade name: Tensilon .

Back  -    New Search

EDTA (ethylenediaminetetraacetic acid) n.

see EDETATE.

Back  -    New Search

Edwards' syndrome (ed-wdz) n.

the condition of a baby born with multiple congenital abnormalities, including mental retardation, due to trisomy of chromosome no. 18. [J. H. Edwards (1928– ), British geneticist]

Back  -    New Search

EEG (electroencephalogram) n.

see ELECTROENCEPHALOGRAPHY.

Back  -    New Search

effector (i-fek-ter) n:

any structure or agent that brings about activity in a muscle or gland. The term is also used for the muscle or gland itself.

Back  -    New Search

efferent (ef-er-nt) adj.

1 designating nerves or neurones that convey impulses from the brain or spinal cord to muscles, glands, and other effectors.

2 designating vessels or ducts that drain fluid from an organ or part. Compare AFFERENT.
Top

Back  -    New Search

effleurage (ef-ler-ahzh) n.

a form of massage in which the hands are passed continuously and rhythmically over a patient's skin in one direction only, with the aim of increasing blood flow in that direction and aiding the dispersal of any swelling due to oedema.

Back  -    New Search

effort syndrome (ef-ert) n.

a condition of marked anxiety about the condition of one's heart and circulatory system. This is accompanied by a heightened consciousness of heartbeat and respiration, which in turn is worsened by the anxiety it induces.

Back  -    New Search

effusion (i-few-zhn) n.

1 the escape of pus, serum, blood, lymph, or other fluid into a body cavity.

2 fluid that has escaped into a body cavity.
Top

Back  -    New Search

eflornithine (ef-lor-ni-theen) n.

a drug used for the treatment of sleeping sickness. It is administered by mouth and intravenous injection. Trade name: DMFO .

Back  -    New Search

egg cell (eg) n.

see OVUM.

Back  -    New Search

ego (eg-oh) n.

(in psychoanalysis) the part of the mind that develops from a person's experience of the outside world and is most in touch with external realities.

Back  -    New Search

Ehrlich's theory (air-liks) n.

an early theory of antibody production, postulating that receptor groups with side chains were carried on cells and combined with antigens. The receptors were then thrown off the cell and became antibodies in the circulation. [P. Ehrlich (1854–1915), German bacteriologist]

Back  -    New Search

eidetic (l-det-ik) adj.

see IMAGERY.

Back  -    New Search

Eisenmenger reaction (l-zn-meng-er) n.

a condition in which pulmonary hypertension is associated with a septal defect, so that blood flows from the right to the left side of the heart or from the pulmonary artery to the aorta.
Oxygen-depleted blood enters the general circulation, which results in cyanosis and polycythaemia. [V. Eisenmenger (1864–1932), German physician]

Back  -    New Search

ejaculation (i-jak-yoo-lay-shn) n.

the discharge of semen from the erect penis at the moment of sexual climax (orgasm) in the male.

Back  -    New Search

elastic cartilage (i-lasst-ik) n.

see CARTILAGE.

Back  -    New Search

elastic tissue n.

strong extensible flexible connective tissue rich in yellow elastic fibres . Elastic tissue is found in the dermis of the skin, in arterial walls, and in the walls of the alveoli of the lungs.

Back  -    New Search

elastin (i-lasst-in) n.

protein forming the major constituent of elastic tissue fibres.

Back  -    New Search

elastography (i-lasst-og-rfi) n.

an ultrasonic imaging technique that displays the elasticity of soft tissues. It has been found useful in demonstrating abnormalities of both muscle and breast tissue.

Back  -    New Search

elation (exaltation) (i-lay-shn) n.

a state of cheerful excitement and enthusiasm. Marked elation of mood is a characteristic of mania or hypomania.

Back  -    New Search

elbow (el-boh) n.

the joint in the arm formed between the ulna and part of the radius and the humerus.

Back  -    New Search

Electra complex (i-lek-tr) n.

the unconscious sexual feelings of a girl for her father, accompanied by aggressive feelings for her mother. Compare OEDIPUS COMPLEX.

Back  -    New Search

electrocardiogram (ECG) (i-lek-troh-kar-di-oh-gram) n.

a recording of the electrical activity of the heart on a moving paper strip. The ECG tracing is recorded by means of an electrocardiograph (see ELECTROCARDIOGRAPHY). It aids in the diagnosis of heart disease, which may produce characteristic changes in the ECG.

Back  -    New Search

electrocardiography (i-lek-troh-kar-di-og-rfi) n.

a technique for recording the electrical activity of the heart. Electrodes connected to the recording apparatus (electrocardiograph ) are placed on the skin of the four limbs and chest wall; the record itself is called an electrocardiogram (ECG).

Back  -    New Search

electrocardiophonography (i-lek-troh-kar-di-oh-f-nog-rfi) n.

a technique for recording heart sounds and murmurs simultaneously with the ECG. The sound is picked up by a microphone placed over the heart. The tracing is a phonocardiogram .

Back  -    New Search

electrocautery (i-lek-troh-kaw-ter-i) n.

the destruction of diseased or unwanted tissue by means of a needle or snare that is electrically heated.

Back  -    New Search

electrocoagulation (i-lek-troh-koh-ag-yoo-lay-shn) n.

the coagulation of tissues by means of a high-frequency electric current concentrated at one point as it passes through them.

Back  -    New Search

electrocochleography (ECoG) (i-lek-troh-kok-li-og-rfi) n.

a test to measure electrical activity produced within the cochlea in response to a sound stimulus. It is used in the diagnosis of Ménière's disease and other forms of sensorineural deafness.

Back  -    New Search

electroconvulsive therapy (ECT, electroplexy) (i-lek-troh-kn-vul-siv) n.

a treatment for severe depression and occasionally for schizophrenia and mania. A convulsion is produced by passing an electric current through the brain; it is modified by giving a muscle relaxant drug and an anaesthetic.

Back  -    New Search

electrode (i-lek-trohd) n.

any part of an electrical conductor or recording device that is used to apply electric current to a part of the body or collect electrical activity (e.g. from the heart or brain).

Back  -    New Search

electrodesiccation (i-lek-troh-dess-i-kay-shn) n.

see FULGURATION.

Back  -    New Search

electroencephalogram (EEG) (i-lek-troh-en-sef--l-gram) n.

see ELECTROENCEPHALOGRAPHY.

Back  -    New Search

electroencephalography (i-lek-troh-en-sef--log-rfi) n.

the technique for recording the electrical activity from different parts of the brain and converting it into a tracing called an electroencephalogram (EEG). The machine that records this activity is known as an encephalograph .
Electroencephalography is mostly used in the diagnosis and management of epilepsy.

Back  -    New Search

electroglottography (i-lek-troh-glot-og-rfi) n.

a method of assessing laryngeal function using external recording electrodes.

Back  -    New Search

electrolysis (i-lek-trol-i-sis) n.

1 the chemical decomposition of a substance (see ELECTROLYTE) into positively and negatively charged ions (see ANION, CATION) when an electric current is passed through it.

2 destruction of tissue, especially hair follicles (see EPILATION), by the passage of an electric current.
Top

Back  -    New Search

electrolyte (i-lek-tr-lyt) n.

a solution that produces ions; for example, sodium chloride solution consists of free sodium and free chloride ions. In medical usage electrolyte usually means the ion itself; thus the serum electrolyte level is the concentration of separate ions (sodium, potassium, chloride, bicarbonate, etc.) in the circulating blood. See also ANION, CATION.

Back  -    New Search

electromyography (i-lek-troh-my-og-rfi) n.

continuous recording of the electrical activity of a muscle by means of electrodes inserted into the muscle fibres. The tracing is displayed on an oscilloscope.

Back  -    New Search

electron (i-lek-tron) n.

a negatively charged particle in an atom, one or more of which orbit around the positively charged nucleus of the atom.

Back  -    New Search

electron microscope n.

a microscope that uses a beam of electrons as a radiation source for viewing the specimen. The resolving power (ability to register fine detail) is a thousand times greater than that of an ordinary light microscope.

Back  -    New Search

electrooculography (i-lek-troh-ok-yoo-log-rfi) n.

an electrical method of recording eye movements by means of tiny electrodes attached to the skin at the inner and outer corners of the eye. The recording is an electrooculogram (EOG).

Back  -    New Search

electroplexy (i-lek-troh-pleks-i) n.

see ELECTROCONVULSIVE THERAPY.

Back  -    New Search

electroretinography (i-lek-troh-ret-in-og-rfi) n.

a method of recording changes in the electrical potential of the retina when it is stimulated by light; the recording is an electroretinogram (ERG). One electrode is placed on the eye in a contact lens and the other is usually attached to the back of the head.

Back  -    New Search

electrosurgery (i-lek-troh-serj-er-i) n.

the use of a high-frequency electric current from a fine wire electrode (a diathermy knife) to cut tissue. The ground electrode is a large metal plate. When used correctly, little heat spreads to the surrounding tissues, in contrast to electrocautery.

Back  -    New Search

electrotherapy (i-lek-troh-th'e-r-pi) n.

the passage of electric currents through the body's tissues to stimulate the functioning of nerves and the muscles that they supply. See also FARADISM, GALVANISM.

Back  -    New Search

electuary (i-lek-tew-er-i) n.

a pharmaceutical preparation in which the drug is made up into a paste with syrup or honey.

Back  -    New Search

element (el-i-mnt) n.

a substance, such as carbon, nitrogen, or oxygen, that cannot be decomposed into simpler substances. All the atoms of an element have the same number of protons. See also ISOTOPE, TRACE ELEMENT.

Back  -    New Search

elephantiasis (el-i-fn-ty--sis) n.

gross enlargement of the skin and underlying connective tissues caused by obstruction of the lymph vessels. Obstruction is commonly caused by the parasitic filarial worms Wuchereria bancrofti and Brugia malayi. The parts most commonly affected are the legs but the scrotum, breasts, and vulva may also be involved. See also FILARIASIS.

Back  -    New Search

elevator (el-i-vay-ter) n.

1 an instrument that is used to raise a depressed broken bone. periosteal e. an instrument used in orthopaedics to strip the fibrous tissue (periosteum) covering bone.

2 a lever-like instrument used to ease a tooth or root out of its socket during extraction.
Top

Back  -    New Search

elimination (i-lim-i-nay-shn) n.

in physiology) the process of excretion of metabolic waste products from the blood by the kidneys and urinary tract.

Back  -    New Search

ELISA n.

see ENZYME-LINKED IMMUNO-SORBENT ASSAY.

Back  -    New Search

elixir (i-liks-er) n.

a preparation containing alcohol (ethanol) or glycerine, which is used as the vehicle for bitter or nauseous drugs.

Back  -    New Search

elliptocytosis (i-lip-toh-sy-toh-sis) n.

the presence of significant numbers of abnormal elliptical red cells (elliptocytes ) in the blood.

Back  -    New Search

em- prefix.

see EN-.

Back  -    New Search

emaciation (i-may-si-ay-shn) n.

wasting of the body, caused by such conditions as malnutrition or cancer.

Back  -    New Search

emasculation (i-mas-kew-lay-shn) n.

strictly, surgical removal of the penis. The term is often used to mean loss of male characteristics, as a result of castration or emotional stress.

Back  -    New Search

embalming (im-bahm-ing) n.

the preservation of a dead body by the introduction of chemical compounds that delay putrefaction.

Back  -    New Search

embolectomy (em-b-lek-tmi) n.

surgical removal of an embolus in order to relieve arterial obstruction.

Back  -    New Search

embolism (em-bl-izm) n.

the condition in which an embolus becomes lodged in an artery and obstructs its blood flow. Treatment is by anticoagulant therapy; major embolism is treated by embolectomy or streptokinase. pulmonary e. obstruction of the pulmonary artery by an embolus, usually a blood clot derived from phlebothrombosis of the leg veins. Large emboli result in acute heart failure. systemic e. embolism affecting any artery except the pulmonary artery. The embolus is often a blood clot formed in the heart in mitral valve disease or following myocardial infarction. See also AIR EMBOLISM.

Back  -    New Search

embolization (therapeutic embolization) (em-bol-l-zay-shn) n.

the introduction of occluding material, such as microspheres, into an artery in order to reduce or obstruct blood flow in such conditions as congenital arteriovenous malformations, angiodysplasia, malignant tumours, or arterial rupture.

Back  -    New Search

embolus (em-b-ls) n. (pl. emboli)

material, such as a blood clot, fat, air, amniotic fluid, or a foreign body, that is carried by the blood from one point in the circulation to lodge at another point (see EMBOLISM).

Back  -    New Search

embrocation (em-broh-kay-shn) n.

a lotion that is rubbed onto the body for the treatment of sprains and strains.

Back  -    New Search

embryo (em-bri-oh) n.

an animal at an early stage of development, before birth (see illustration). In humans the term refers to the products of conception within the uterus up to the eighth week of development, during which time all the main organs are formed. Compare FETUS.

—embryonic (em-bri-on-ik) adj.

Back  -    New Search

embryology (em-bri-ol-ji) n.

the study of growth and development of the embryo and fetus from fertilization of the ovum until birth.
—embryological adj.

Back  -    New Search

embryoscopy (em-bri-os-kpi) n.

examination of an embryo or fetus during the first 12 weeks of pregnancy by means of a fibreoptic endoscope inserted through the cervix. Direct visualization of the embryo or fetus permits the diagnosis of malformations.

Back  -    New Search

emesis (em-i-sis) n.

see VOMITING.

Back  -    New Search

emetic (i-met-ik) n.

an agent that causes vomiting, such as apomorphine, ipecacuanha, or common salt.

Back  -    New Search

eminence (emin-ns) n.

a projection, often rounded, on an organ or tissue, particularly on a bone.

Back  -    New Search

Emiscan (em-i-skan) n.

trade name for computerized tomography: a development of diagnostic radiology for the examination of the soft tissues of the body. See also CT SCANNER.

Back  -    New Search

emissary veins (em-iss-er-i) pl. n.

a group of veins within the skull that drain blood from the venous sinuses of the dura mater to veins outside the skull.

Back  -    New Search

emission (i-mish-n) n.

the flow of semen from the erect penis, usually occurring while the subject is asleep (nocturnal e. ).

Back  -    New Search

EMLA cream (em-l) n.

a cream containing a eutectic mixture of local anaesthetics. Applied to the skin as a thick coating, it gives a helpful degree of local anaesthesia, allowing blood samples to be taken and facilitating biopsy procedures in young children.

Back  -    New Search

emmetropia (em-i-troh-pi) n.

the state of refraction of the normal eye, in which parallel light rays are brought to a focus on the retina with the accommodation relaxed. Compare AMETROPIA, HYPERMETROPIA, MYOPIA.

Back  -    New Search

emollient (i-mol-int) n.

an agent that soothes and softens the skin, such as lanolin or liquid paraffin. Emollients are used alone as moisturizers to lessen the need for active drug therapy (such as corticosteroids for eczema) and in skin preparations as a base for more active drugs, such as antibiotics.

Back  -    New Search

emotion (i-moh-shn) n.

a state of arousal that can be experienced as pleasant or unpleasant. Emotions can have three components: for example, fear can involve an unpleasant subjective experience, an increase in physiological measures such as heart rate, and a tendency to flee from the situation provoking the fear.

Back  -    New Search

empathy (em-p-thi) n.

the ability to understand the thoughts and emotions of another person.

Back  -    New Search

emphysema (em-fi-see-m) n.

air in the tissues. pulmonary e. emphysema in which the alveoli of the lungs are enlarged and damaged, which reduces the surface area for the exchange of oxygen and carbon dioxide. Severe emphysema causes breathlessness, which is made worse by infections. surgical e. emphysema in which air escapes into surrounding tissues through wounds or surgical incisions, usually into the tissues of the chest and neck from leaks in the lungs or oesophagus. Bacteria may form gas in soft tissues.

Back  -    New Search

empirical (im-pi-ri-kl) adj.

describing a system of treatment based on experience or observation, rather than of logic or reason.

Back  -    New Search

Employment Service (im-ploi-mnt) n.

an executive agency with responsibility for running public employment services, including the employment and training of the disabled.

Back  -    New Search

empyema (pyothorax) (em-py-ee-m) n.

pus in the pleural cavity, usually secondary to infection in the lung or in the space below the diaphragm.

Back  -    New Search

emulsion (i-mul-shn) n.

a preparation in which fine droplets of one liquid (such as oil) are dispersed in another liquid (such as water). In pharmacy medicines are prepared in the form of emulsions to disguise the taste of an oil, which is dispersed in a flavoured liquid.

Back  -    New Search

EN n.

see ENROLLED NURSE.

Back  -    New Search

en- (em-) prefix

denoting in; inside.

Back  -    New Search

enamel (i-nam-l) n.

the extremely hard outer covering of the crown of a tooth, which consists of crystalline hydroxyapatite.

Back  -    New Search

enalapril (en-al--pril) n.

a drug administered by mouth for the treatment of high blood pressure (hypertension). It inhibits the action of angiotensin, which results in decreased vasopressor (blood-vessel constricting) activity and decreased aldosterone secretion. Trade name: Innovace .

Back  -    New Search

enarthrosis (en-arth-roh-sis) n.

a ball-and-socket joint, e.g. the shoulder joint. Such a joint always involves a long bone, which is thus allowed to move in all planes.

Back  -    New Search

encapsulated (in-kaps-yoo-layt-id) adj.

(of an organ, tumour, bacterium, etc.) enclosed in a capsule.

Back  -    New Search

encephal- (encephalo-) prefix

denoting the brain.

Back  -    New Search

encephalin (enkephalin) (en-sef--lin) n.

a peptide occurring naturally in the brain and having effects resembling those of morphine or other opiates. See also ENDORPHIN.

Back  -    New Search

encephalitis (en-sef--ly-tis) n.

inflammation of the brain. It may be caused by a viral or bacterial infection or it may be part of an allergic response to a systemic viral illness or vaccination (see ENCEPHALO-MYELITIS). e. lethargica a form of viral encephalitis that is marked by headache and drowsiness, progressing to coma (hence its popular name — sleepy sickness ). It can cause postencephalitic parkinsonism.

Back  -    New Search

encephalocele (en-sef--loh-seel) n.

protrusion of the brain through a defect in the bones of the skull. See NEURAL TUBE DEFECTS.

Back  -    New Search

encephalography (en-sef--log-rfi) n.

any of various techniques for recording the structure of the brain or the activity of the brain cells. See ECHOENCEPHALOGRAPHY, ELECTROENCEPHALOGRAPHY, PNEUMOENCEPHALOGRAPHY.

Back  -    New Search

encephaloid (en-sef--loid) adj.

having the appearance of brain tissue: applied to certain tumours.

Back  -    New Search

encephaloma (en-sef--loh-m) n.

a brain tumour.

Back  -    New Search

encephalomalacia (en-sef--loh-m-lay-shi) n.

softening of the brain.

Back  -    New Search

encephalomyelitis (en-sef--loh-my--ly-tis) n.

an acute inflammatory disease affecting the brain and spinal cord. acute disseminated e. a form of delayed tissue hypersensitivity provoked by a mild infection or vaccination 7–10 days earlier.

Back  -    New Search

encephalomyelopathy (en-sef--loh-my--lop--thi) n.

any condition in which there is widespread disease of the brain and spinal cord.

Back  -    New Search

encephalon (en-sef--lon) n.

see BRAIN.

Back  -    New Search

encephalopathy (en-sef--lop--thi) n.

any of various diseases that affect the functioning of the brain. See HEPATIC (ENCEPHALOPATHY), SPONGIFORM ENCEPHALOPATHY, WERNICKE'S ENCEPHALOPATHY.

Back  -    New Search

enchondroma (en-kon-droh-m) n. (pl. enchondromata)

a benign cartilaginous tumour (see CHONDROMA) occurring in the growing zone of a bone and not protruding beyond its margins. Compare ECCHONDROMA.

Back  -    New Search

encopresis (en-koh-pree-sis) n.

incontinence of faeces. The term is used for faecal soiling in a child who has gained bowel control but passes formed stools in unacceptable places.

Back  -    New Search

encounter group (in-kown-ter) n.

a form of group psychotherapy. The emphasis is on encouraging close relationships between group members and on the expression of feelings.

Back  -    New Search

encysted (en-sist-id) adj.

enclosed in a cyst.

Back  -    New Search

end- (endo-) prefix

denoting within or inner.

Back  -    New Search

endarterectomy (end-ar-ter-ek-tmi) n.

a surgical ‘re-bore’ of an artery that has become obstructed by atheroma with or without a blood clot (thrombus); the former operation is known as thromboendarterectomy . The inner part of the wall is removed together with any clot that is present. carotid e. endarterectomy of one or more of the carotid arteries.

Back  -    New Search

endarteritis (end-ar-ter-l-tis) n.

chronic inflammation of the inner portion of the wall of an artery, which most often results from late syphilis. Thickening of the wall produces progressive arterial obstruction and symptoms from reduced blood supply to the affected part.

Back  -    New Search

end artery (end) n.

the terminal branch of an artery, which does not communicate with other branches.

Back  -    New Search

endaural (end-or-l) adj.

within the ear, especially relating to the external auditory meatus of the outer ear.

Back  -    New Search

endemic (en-dem-ik) adj.

occurring frequently in a particular region or population: applied to diseases that are generally or constantly found among people in a particular area. Compare EPIDEMIC, PANDEMIC.

Back  -    New Search

endemic syphilis n.

see BEJEL.

Back  -    New Search

endemiology (en-dee-mi-ol-ji) n.

the study of endemic disease.

Back  -    New Search

endocarditis (en-doh-kar-dy-tis) n.

inflammation of the endocardium and heart valves. It is most often due to rheumatic fever or bacterial infection (bacterial e. ). The main features are fever, changing heart murmurs, heart failure, and embolism. See also SUBACUTE BACTERIAL ENDOCARDITIS.

Back  -    New Search

endocardium (en-doh-kar-dim) n.

a delicate membrane that lines the heart and is continuous with the lining of arteries and veins.
—endocardial adj.

Back  -    New Search

endocervicitis (en-doh-ser-vi-sy-tis) n.

inflammation of the membrane lining the cervix (neck) of the uterus, usually caused by infection. The condition is accompanied by a thick mucoid discharge.

Back  -    New Search

endocervix (en-doh-ser-viks) n.

the mucous membrane lining the cervix of the uterus.

Back  -    New Search

endochondral (en-doh-kon-drl) adj.

within the material of a cartilage.

Back  -    New Search

endocrine gland (ductless gland) (end-oh-kryn) n.

a gland that manufactures one or more hormones and secretes them directly into the bloodstream (and not through a duct to the exterior). Endocrine glands include the pituitary, thyroid, parathyroid, and adrenal glands, the ovary and testis, the placenta, and part of the pancreas.

Back  -    New Search

endocrinology (en-doh-kri-nol-ji) n.

the study of the endocrine glands and the hormones they secrete.
—endocrinologist n.

Back  -    New Search

endoderm (end-oh-derm) n.

the inner of the three germ layers of the early embryo, which gives rise to the lining of most of the alimentary canal and its associated glands, the lining of the bronchi and alveoli of the lung, and most of the urinary tract.
—endodermal (en-doh-der-ml) adj.

Back  -    New Search

endodermal sinus tumour n.

a rare tumour of fetal remnants of the ovaries or testes.

Back  -    New Search

endogenous (en-doj-in-s) adj.

arising within or derived from the body. Compare EXOGENOUS.

Back  -    New Search

endolymph (end-oh-limf) n.

the fluid that fills the membranous labyrinth of the ear.

Back  -    New Search

endolysin (en-dol-i-sin) n.

a substance within a cell that has a specific destructive action against bacteria.

Back  -    New Search

endometrial (en-doh-mee-tri-l) adj.

relating to or affecting the lining of the uterus (endometrium). e. ablation an operation to remove the entire endometrium, usually to treat menorrhagia. It is performed under local anaesthetic either by means of a laser, which destroys the endometrium in situ, or by electrosurgery. e. aspiration the removal, by means of suction, of a sample of endometrial tissue for diagnostic purposes. e. hyperplasia an increase in the thickness of the cells of the endometrium, usually due to prolonged exposure to unopposed oestrogen (e.g. from HRT or an oestrogen-secreting tumour). Atypical cells may be present.

Back  -    New Search

endometriosis (en-doh-mee-tri-oh-sis) n.

the presence of tissue similar to the kind lining the uterus (endometrium) at other sites in the pelvis. The condition causes pelvic pain and severe dysmenorrhoea.

Back  -    New Search

endometritis (en-doh-mi-try-tis) n.

inflammation of the endometrium due to acute or chronic infection. It may be caused by foreign bodies, bacteria, viruses, or parasites. Chronic endometritis may be responsible for the contraceptive action of IUCDs.

Back  -    New Search

endometrium (en-doh-mee-tri-m) n.

the mucous membrane lining the uterus. It becomes thicker and more vascular during the latter part of the menstrual cycle and much of it breaks down and is lost in menstruation. If pregnancy becomes established the endometrium becomes the decidua.

Back  -    New Search

endomorphic (en-doh-mor-fik) adj.

describing a body type that is relatively fat, with highly developed viscera and weak muscular and skeletal development.
—endomorph n. —endomorphy n.

Back  -    New Search

endomyocarditis (en-doh-my-oh-kar-dy-tis) n.

an acute or chronic inflammatory disorder of the muscle and lining membrane of the heart. The principal causes are rheumatic fever and virus infections. There is enlargement of the heart, murmurs, embolism, and frequently arrhythmias.

Back  -    New Search

endomysium (en-doh-miz-im) n.

the fine connective tissue sheath that surrounds a single muscle fibre.

Back  -    New Search

endoneurium (en-doh-newr-im) n.

the layer of fibrous tissue that separates individual fibres within a nerve.

Back  -    New Search

endoparasite (en-doh-pa-r-syt) n.

a parasite that lives inside its host, for example in the liver, lungs, gut, or other tissues of the body. Compare ECTOPARASITE.

Back  -    New Search

endophthalmitis (end-off-thal-my-tis) n.

inflammation, usually due to infection, within the eye.

Back  -    New Search

endoplasmic reticulum (ER) (en-doh-plaz-mik) n.

a system of membranes present in the cytoplasm of cells. It is the site of manufacture of proteins and lipids and is concerned with the transport of these products within the cell (see also GOLGI APPARATUS).

Back  -    New Search

end organ n.

a specialized structure at the end of a peripheral nerve, such as the taste buds in the tongue, acting as a receptor for a particular sensation.

Back  -    New Search

endorphin (en-dor-fin) n.

one of a group of peptides that occur naturally in the brain and have pain-relieving properties similar to those of the opiates. See also ENCEPHALIN.

Back  -    New Search

endoscope (end-oh-skohp) n.

any instrument, such as an auriscope or a gastroscope, used to obtain a view of the interior of the body. Most endoscopes consist of a tube with a light at the end and an optical system or a miniature video camera for transmitting an image to the examiner's eye. See also FIBRESCOPE.
—endoscopic (en-doh-skop-ik) adj. —endoscopy (en-dos-k-pi) n.

Back  -    New Search

endoscopic retrograde cholangiopancreatography n.

see ERCP.

Back  -    New Search

endospore (end-oh-spor) n.

the resting stage of certain bacteria, particularly species of the genera Bacillus and Clostridium.

Back  -    New Search

endostapler (end-oh-stay-pler) n.

a stapling instrument (see STAPLE) used endoscopically for purposes of fixing tissues or joining them together.

Back  -    New Search

endosteum (en-dos-tim) n.

the membrane that lines the marrow cavity of a bone.

Back  -    New Search

endothelioma (en-doh-th'ee-li-oh-m) n.

any tumour arising from or resembling endothelium.

Back  -    New Search

endothelium (en-doh-th'ee-li-um) n.

the single layer of cells that lines the heart, blood vessels, and lymphatic vessels. It is derived from embryonic mesoderm. Compare EPITHELIUM.
—endothelial adj.

Back  -    New Search

endotoxin (en-doh-toks-in) n.

a poison generally harmful to all body tissues, contained within certain Gram-negative bacteria and released only when the bacterial cell is broken down or dies and disintegrates. Compare EXOTOXIN.

Back  -    New Search

endotracheal (en-doh-tray-ki-l) adj.

within or through the trachea. e. tube a catheter inserted into the trachea to maintain a patent airway, administer oxygen or an anaesthetic, etc. See also INTUBATION.

Back  -    New Search

end-plate (end-playt) n.

the area of muscle cell membrane immediately beneath the motor nerve ending at a neuromuscular junction.

Back  -    New Search

enema (en-im-) n. (pl. enemata or enemas)

a quantity of fluid infused into the rectum through a tube passed into the anus. barium e. an enema using barium sulphate, given to demonstrate the colon by X-ray. double-contrast barium e. a barium enema using air insufflation to distend the large bowel. evacuant e. an enema using soap or olive oil to remove faeces. therapeutic e. an enema used to insert drugs into the rectum.

Back  -    New Search

enervation (en-er-vay-shn) n.

1 weakness; loss of strength.

2 the surgical removal of a nerve.
Top

Back  -    New Search

engagement (in-gayj-mnt) n.

(in obstetrics) the stage of pregnancy that occurs when the presenting part of the fetus has descended into the mother's pelvis. Engagement of the fetal head occurs when the widest part has passed through the pelvic inlet.

Back  -    New Search

enhanced role (en-hahnst) n.

of the nurse) see EXTENDED ROLE.

Back  -    New Search

enkephalin (en-kef--lin) n.

see ENCEPHALIN.

Back  -    New Search

enophthalmos (en-off-thal-ms) n.

a condition in which the eye is abnormally sunken into the socket.

Back  -    New Search

enostosis (en-os-toh-sis) n.

a benign growth within a bone.

Back  -    New Search

enoximone (en-oks-i-mohn) n.

an inotropic drug used in heart failure to increase the force and output of the heart. It is administered by injection. Trade name: Perfan .

Back  -    New Search

enrolled nurse (EN) (en-rohld) n.

(in the UK) a nurse who has undergone a two-year programme of nursing education (see SECOND-LEVEL NURSE). Entry to the second-level part of the Register may be in general, mental, or mental handicap nursing in England and Wales. In Scotland and Northern Ireland there is generic training for second-level qualification.

Back  -    New Search

ensiform cartilage (en-si-form) n.

see XIPHOID PROCESS.

Back  -    New Search

ENT n.

ear, nose, and throat. See OTORHINOLARYNGOLOGY.

Back  -    New Search

Entamoeba (ent--mee-b) n.

a genus of widely distributed amoebae. E. coli a harmless intestinal parasite. E. gingivalis a species found between the teeth; it is associated with periodontal disease and gingivitis. E. histolytica a species that invades the intestinal wall, causing amoebic dysentery and ulceration; infection of the liver with this species (amoebic hepatitis) is common in tropical countries.

Back  -    New Search

enter- (entero-) prefix

denoting the intestine.

Back  -    New Search

enteral (en-ter-l) adj.

of or relating to the intestinal tract. e. feeding see NUTRITION.

Back  -    New Search

enteralgia (en-ter-al-ji) n.

see COLIC.

Back  -    New Search

enterectomy (en-ter-ek-tmi) n.

surgical removal of part of the intestine.

Back  -    New Search

enteric (en-te-rik) adj.

relating to or affecting the intestine. e. fever see PARATYPHOID FEVER, TYPHOID FEVER.

Back  -    New Search

enteric-coated adj.

describing tablets that are coated with a substance that enables them to pass through the stomach to the intestine unchanged.

Back  -    New Search

enteritis (en-ter-I-tis) n.

inflammation of the small intestine, usually causing diarrhoea. infective e. enteritis caused by viruses or bacteria. radiation e. enteritis caused by X-rays or radioactive isotopes. See also CROHN'S DISEASE (REGIONAL ENTERITIS), GASTROENTERITIS.

Back  -    New Search

enterobiasis (oxyuriasis) (en-ter-oh-by--sis) n.

a disease, common in children throughout the world, caused by the parasitic nematode Enterobius vermicularis (see THREADWORM) in the large intestine. The worms do not cause any serious lesions of the gut wall although, rarely, they may provoke appendicitis. Enterobiasis responds well to treatment with piperazine compounds.

Back  -    New Search

Enterobius (Oxyuris) (en-ter-oh-bis) n.

see THREADWORM.

Back  -    New Search

enterocele (en-ter-oh-seel) n.

a hernia of the pouch of Douglas (between the rectum and uterus) into the upper part of the posterior vaginal wall.

Back  -    New Search

enterocentesis (en-ter-oh-sen-tee-sis) n.

a surgical procedure in which a hollow needle is pushed through the wall of the stomach or intestines to release an abnormal accumulation of gas or fluid or to introduce a catheter for feeding (see GASTROSTOMY, ENTEROSTOMY).

Back  -    New Search

enterococcus (en-ter-oh-kok-s) n.

any bacterium of the genus Streptococcus that inhabits the human intestine.

Back  -    New Search

enterocolitis (en-ter-oh-k-ly-tis) n.

inflammation of the colon and small intestine. See also COLITIS, ENTERITIS, NECROTIZING ENTEROCOLITIS.

Back  -    New Search

enterogenous (en-ter-oj-i-ns) adj.

borne by or carried in the intestine.

Back  -    New Search

enterokinase (en-ter-oh-ky-nayz) n.

the former name for enteropeptidase.

Back  -    New Search

enterolith (en-ter-oh-lith) n.

a stone within the intestine. It usually builds up around a gallstone or a swallowed fruit stone.

Back  -    New Search

enteron (en-ter-on) n.

the intestinal tract.

Back  -    New Search

enteropathy (en-ter-op--thi) n.

disease of the small intestine. See also COELIAC DISEASE (GLUTEN-INDUCED ENTEROPATHY).

Back  -    New Search

enteropeptidase (en-ter-oh-pep-ti-dayz) n.

an enzyme secreted by the glands of the small intestine that acts on trypsinogen to produce trypsin.

Back  -    New Search

enteroptosis (en-ter-op-toh-sis) n.

a condition in which loops of intestine (especially transverse colon) are in a low anatomical position.

Back  -    New Search

enterorrhaphy (en-ter-o-r-fi) n.

the surgical procedure of stitching an intestine that has either perforated or been divided during an operation.

Back  -    New Search

enteroscope (en-ter-oh-skohp) n.

an illuminated optical instrument used to inspect the interior of the small intestine. The image is transmitted through a fibreoptic bundle or by a tiny video-camera. The push type is introduced by guidance under direct vision. The sonde type has an inflatable balloon that pulls the instrument through the length of the intestine by peristalsis. The enteroscope is useful in diagnosing the cause of haemorrhage of the small intestine or of strictures.
—enteroscopy (en-ter-os-kpi) n.

Back  -    New Search

enterostomy (en-ter-ost-mi) n.

an operation in which the small intestine is brought through the abdominal wall and opened (see DUODENOSTOMY, JEJUNOSTOMY, ILEOSTOMY) or is joined to the stomach (gastroenterostomy ) or to another loop of small intestine (enteroenterostomy ).

Back  -    New Search

enterotomy (en-ter-ot-mi) n.

surgical incision into the intestine.

Back  -    New Search

enterotoxin (en-ter-oh-toks-in) n.

a poisonous substance that has a particularly marked effect upon the gastrointestinal tract, causing vomiting, diarrhoea, and abdominal pain.

Back  -    New Search

enterovirus (en-ter-oh-vy-rs) n.

any virus that enters the body through the gastrointestinal tract, multiplies there, and then (generally) invades the central nervous system. Enteroviruses include Coxsackie viruses and polioviruses.

Back  -    New Search

enterozoon (en-ter-oh-zoh-on) n.

any animal species inhabiting or infecting the gut of another. See also ENDOPARASITE.

Back  -    New Search

enthesis (en-th'ee-sis) n.

the junction of tendon and bone.

Back  -    New Search

enthesopathy (en-theez-op--thi) n.

any rheumatic disease resulting in inflammation of entheses. Ankylosing spondylitis, psoriatic arthritis, and Reiter's disease are examples.

Back  -    New Search

entrapment neuropathy (en-trap-mnt) n.

pain, muscle wasting, and paralysis resulting from pressure on a nerve in conditions in which it is subjected to compression by surrounding structures. See CARPAL TUNNEL SYNDROME.

Back  -    New Search

entropion (en-troh-pi-on) n.

inturning of the eyelid towards the eyeball. The lashes may rub against the eye and cause irritation (see TRICHIASIS).

Back  -    New Search

enucleation (i-new-kli-ay-shn) n.

a surgical operation in which an organ, tumour, or cyst is completely removed. In ophthalmology it is an operation in which the eyeball is removed but the other structures in the socket are left in place prior to fitting an artificial eye.

Back  -    New Search

enuresis (en-yoor-ee-sis) n.

the involuntary passing of urine, especially bedwetting by children at night (nocturnal e. ). See also INCONTINENCE.
—enuretic (en-yoor-et-ik) adj.

Back  -    New Search

environment (in-vyr-n-mnt) n.

any or all aspects of the surroundings of an organism, both internal and external, which influence its growth, development, and behaviour.

Back  -    New Search

Environmental Health Officer (EHO) (in-vyr-n-men-tl) n.

a person, employed by a local authority, who has special training in such aspects of environmental health and pollution as housing, sanitation, food, clean air, and water supplies (formerly known as a Public Health Inspector ).

Back  -    New Search

enzyme (en-zym) n.

a protein that, in small amounts, speeds up the rate of a biological reaction without itself being used up in the reaction (i.e. it acts as a catalyst). Enzymes are essential for the normal functioning and development of the body. Failure in the production or activity of a single enzyme may result in metabolic disorders; such disorders are often inherited and some have serious effects.
—enzymatic adj.

Back  -    New Search

enzyme-linked immunosorbent assay (ELISA) n.

a sensitive technique for measuring the amount of a substance. An antibody that will bind to the substance is produced; the amount of an easily measured enzyme that then binds to the antibody complex enables accurate measurement.

Back  -    New Search

EOG n.

see ELECTROOCULOGRAPHY.

Back  -    New Search

eonism (ee--nizm) n.

the adoption of female manners and dress by a man. See TRANSSEXUALISM, TRANSVESTITISM.

Back  -    New Search

eosin (ee-oh-sin) n.

a red acidic dye, produced by the reaction of bromine and fluorescein, used to stain biological specimens for microscopical examination.

Back  -    New Search

eosinopenia (ee-oh-sin-oh-pee-ni) n.

a decrease in the number of eosinophils in the blood.

Back  -    New Search

eosinophil (ee-oh-sin--fil) n.

a variety of white blood cell distinguished by the presence in its cytoplasm of coarse granules that stain orange-red with Romanowsky stains. Eosinophils are capable of ingesting foreign particles and are involved in allergic responses.

Back  -    New Search

eosinophilia (ee-oh-sin--fil-i) n.

an increase in the number of eosinophils in the blood. Eosinophilia occurs in response to certain drugs and in a variety of diseases, including allergies, parasitic infestations, and certain forms of leukaemia.

Back  -    New Search

eparterial (ep-ar-teer-il) adj.

situated on or above an artery.

Back  -    New Search

ependyma (ep-en-dim-) n.

the extremely thin membrane, composed of cells of the glia (ependymal cells ), that lines the ventricles of the brain and the choroid plexuses. It is responsible for helping to form cerebrospinal fluid.
—ependymal adj.

Back  -    New Search

ependymoma (ep-en-di-moh-m) n.

a cerebral tumour derived from the glial ependymal cells. It may obstruct the flow of cerebrospinal fluid, causing a hydrocephalus.

Back  -    New Search

ephebiatrics (i-fee-bi-at-riks) n.

the branch of medicine concerned with the common disorders of children and adolescents. Compare PAEDIATRICS.

Back  -    New Search

ephedrine (ef-i-drin) n.

a drug that causes constriction of blood vessels and widening of the bronchial passages (see SYMPATHOMIMETIC). It is administered by mouth or by inhalation, mainly in the treatment of asthma and other allergic conditions and chronic bronchitis.

Back  -    New Search

epi- prefix

denoting above or upon.

Back  -    New Search

epiblepharon (epi-blef-er-on) n.

an abnormal fold of skin, present from birth, stretching across the eye just above the lashes of the upper eyelid or in front of them in the lower lid. It usually disappears within the first year of life.

Back  -    New Search

epicanthus (epicanthic fold) (epi-kanth-s) n.

a vertical fold of skin from the upper eyelid that covers the inner corner of the eye. It occurs abnormally in certain congenital conditions, e.g. Down's syndrome.
—epicanthal, epicanthic adj.

Back  -    New Search

epicardium (epi-kar-dim) n.

the outermost layer of the heart wall, enveloping the myocardium. It is a serous membrane that forms the inner layer of the serous pericardium.
—epicardial adj.

Back  -    New Search

epicondyle (epi-kon-dyl) n.

the protuberance above a condyle at the end of an articulating bone.

Back  -    New Search

epicranium (epi-kray-nim) n.

the structures that cover the cranium, i.e. all layers of the scalp.

Back  -    New Search

epicranius (epi-kray-ni-s) n.

the muscle of the scalp.

Back  -    New Search

epicritic (epi-krit-ik) adj.

describing or relating to sensory nerve fibres responsible for the fine degrees of sensation, as of temperature and touch. Compare PROTOPATHIC.

Back  -    New Search

epidemic (epi-dem-ik) n.

a sudden outbreak of infectious disease that spreads rapidly through the population, affecting a large proportion of people. Compare ENDEMIC, PANDEMIC.
—epidemic adj.

Back  -    New Search

epidemiology (epi-dee-mi-ol-ji) n.

the study of the occurrence, distribution, and control of infectious and noninfectious diseases in populations, including all forms of disease that relate to the environment and ways of life.

Back  -    New Search

epidermis (epi-der-mis) n.

the outer layer of the skin, which is divided into four layers (see illustration). The top three layers are continually renewed as cells from the continuously dividing Malpighian layer are gradually pushed outwards and become progressively impregnated with keratin (see KERATINIZATION).

—epidermal adj.

Back  -    New Search

epidermoid cyst (epi-der-moid) n.

see SEBACEOUS CYST.

Back  -    New Search

epidermolysis bullosa (epi-der-mol-i-sis buul-oh-s) n.

any one of a group of genetically determined disorders characterized by blistering of skin and mucous membranes. In the simple forms the blistering is induced by injury. In the more serious (dystrophic) forms the blistering may occur spontaneously; some of the dystrophic forms of the disease are fatal.

Back  -    New Search

Epidermophyton (epi-der-mof-i-tn) n.

a genus of fungi that grow on the skin, causing tinea (ringworm). See also DERMATOPHYTE.

Back  -    New Search

epidiascope (epi-dy--skohp) n.

an apparatus for projecting a greatly magnified image of an object, such as a specimen on a microscope slide, on to a screen.

Back  -    New Search

epididymectomy (epi-did-i-mek-tmi) n.

the surgical removal or excision of the epididymis.

Back  -    New Search

epididymis (epi-did-i-mis) n. (pl. epididymides)

a highly convoluted tube, about seven metres long, that connects the testis to the vas deferens. The spermatozoa are moved along the tube and are stored in the lower part until ejaculation.
—epididymal adj.

Back  -    New Search

epididymitis (epi-did-i-my-tis) n.

inflammation of the epididymis. The usual cause is infection spreading down the vas deferens from the bladder or urethra. The inflammation may spread to the testicle (epididymo-orchitis ).

Back  -    New Search

epididymovasostomy (epi-did-i-moh-vayz-os-tmi) n.

the operation of connecting the vas deferens to the epididymis to bypass obstruction of the latter. It is performed in an attempt to cure azoospermia caused by this blockage.

Back  -    New Search

epidural (extradural) (epi-dewr-l) adj.

on or over the dura mater. e. space the space between the dura mater of the spinal cord and the vertebral canal. It is used for anaesthetizing spinal nerve roots, especially to provide pain relief during childbirth or to reduce the need for deep general anaesthesia. See also SPINAL ANAESTHESIA.

Back  -    New Search

epigastrium (epi-gas-tri-m) n.

the upper central region of the abdomen.
—epigastric adj.

Back  -    New Search

epigastrocele (epi-gas-troh-seel) n.

a hernia through the upper central abdominal wall.

Back  -    New Search

epiglottis (epi-glot-iss) n.

a thin leaf-shaped flap of cartilage, covered with mucous membrane, that is situated immediately behind the root of the tongue. It covers the entrance to the larynx during swallowing.

Back  -    New Search

epiglottitis (epi-glot-l-tis) n.

swelling and inflammation of the epiglottis and other parts of the supraglottis, obstructing air flow to the lungs.

Back  -    New Search

epikeratophakia (epi-ke-r-toh-fay-ki) n.

eye surgery to correct errors of refraction in which the curvature of the cornea is altered using donor corneal tissue, which has been frozen and shaped using a lathe to produce a tissue lens that is then sutured onto the cornea.

Back  -    New Search

epilation (epi-lay-shn) n.

the removal of a hair by its roots. This can be done mechanically or by electrolysis; lasers for epilation are now available.

Back  -    New Search

epilepsy (ep-i-lep-si) n.

any one of a group of disorders of brain function characterized by recurrent attacks that have a sudden onset. Seizures may be generalized or partial. Generalized seizures may take the form of major (tonic-clonic or grand mal ) seizures. The tonic phase begins when the patient falls to the ground unconscious with his muscles in a state of spasm. This is replaced by the convulsive movements of the clonic phase, when the tongue may be bitten and urinary incontinence may occur. Minor or petit mal seizures (absences ) are brief spells of unconsciousness, lasting for a few seconds, during which posture and balance are maintained and the eyes stare blankly. A form of partial idiopathic epilepsy, they seldom appear before the age of three or after adolescence and often subside spontaneously in adult life, although they may be followed by the onset of major epilepsy. focal e. epilepsy caused by structural disease of the brain. idiopathic e. epilepsy that is not associated with structural damage to the brain. Jacksonian e. focal motor epilepsy in which the convulsive movements may spread from the thumb to the hand, arm, and face. temporal lobe (or psychomotor ) e. focal epilepsy caused by disease in the cortex of the temporal lobe or the adjacent parietal lobe of the brain. Its symptoms include hallucinations of smell, taste, sight, and hearing, paroxysmal disorders of memory, and automatism.
—epileptic (epi-lep-tik) adj., n.

Back  -    New Search

epileptiform (epi-lep-ti-form) adj.

resembling an epileptic attack.

Back  -    New Search

epileptogenic (epi-lep-toh-jen-ik) adj.

having the capacity to provoke epileptic seizures.

Back  -    New Search

epiloia (epi-loi-) n.

see TUBEROUS (SCLEROSIS).

Back  -    New Search

epimenorrhagia (epi-men--ray-ji) n.

see MENORRHAGIA.

Back  -    New Search

epimenorrhoea (epi-men--ree-) n.

menstruation at shorter intervals than is normal.

Back  -    New Search

epinephrine (epi-nef-rin) n.

see ADRENALINE.

Back  -    New Search

epineurium (epi-newr-im) n.

the outer sheath of connective tissue that encloses the bundles (fascicles) of fibres that make up a nerve.

Back  -    New Search

epiphenomenon (epi-fin-om-inn) n.

an unusual symptom or event that may occur simultaneously with a disease but is not necessarily directly related to it. Compare COMPLICATION.

Back  -    New Search

epiphora (i-pif-er-) n.

watering of the eye, in which tears flow onto the cheek. It is due to some abnormality of the tear drainage system: see LACRIMAL (APPARATUS).

Back  -    New Search

epiphysis (i-pif-i-sis) n.

1 the end of a long bone, which is initially separated by cartilage from the shaft (diaphysis) of the bone and develops separately. It eventually fuses with the diaphysis to form a complete bone.

2 see PINEAL GLAND.
Top

—epiphyseal (epi-fiz-il) adj.

Back  -    New Search

epiphysitis (ep-ifi-sy-tis) n.

inflammation of the epiphysis of a long bone.

Back  -    New Search

epiplo- prefix

denoting the omentum.

Back  -    New Search

epiplocele (i-pip-loh-seel) n.

a hernia that contains omentum.

Back  -    New Search

epiploon (i-pip-loh-on) n.

see OMENTUM.

Back  -    New Search

episclera (epi-skleer-) n.

the outermost covering of the sclera of the eye, which provides nutritional support to the sclera.

Back  -    New Search

episcleritis (epi-skleer-l-tis) n.

inflammation of the outermost layer of the sclera of the eyeball, resulting in a red painful eye that is sensitive to light.

Back  -    New Search

episio- prefix

denoting the vulva.

Back  -    New Search

episiorrhaphy (ep-izi-o-rfi) n.

stitching together the margins of a tear in the tissues around the vaginal opening.

Back  -    New Search

episiotomy (ep-izi-ot-mi) n.

an incision into the perineum during a difficult birth. The aim is to make delivery easier and to avoid extensive tearing of adjacent tissues.

Back  -    New Search

epispadias (epi-spay-di-s) n.

a congenital abnormality in which the opening of the urethra is on the dorsal (upper) surface of the penis. Surgical correction is carried out in infancy.

Back  -    New Search

epistaxis (epi-staks-iss) n.

see NOSEBLEED.

Back  -    New Search

epithalaxia (epi-thal-aks-i) n.

loss of layers of epithelial cells from the lining of the intestine.

Back  -    New Search

epithelialization (epi-th'ee-li--ly-zay-shn) n.

the growth of epithelium over the surface of a wound, which marks the final stage of healing.

Back  -    New Search

epithelioma (epi-th'ee-li-oh-m) n.

a tumour of epithelium: a former term for carcinoma.

Back  -    New Search

epithelium (epi-theel-im) n.

the tissue that covers the external surface of the body and lines hollow structures (except blood and lymphatic vessels). Epithelium may be either simple , consisting of a single layer of cells; stratified , consisting of several cell layers; or pseudostratified , in which the cells appear to be arranged in layers but in fact share a common basement membrane. See illustration. See also ENDOTHELIUM, MESOTHELIUM.

—epithelial adj.

Back  -    New Search

eponym (ep--nim) n.

a disease, structure, or species named after a particular person, usually the person who first discovered or described it.
—eponymous (i-pon-i-ms) adj.

Back  -    New Search

epoprostenol (ee-poh-pros-ti-nol) n.

a prostaglandin drug used immediately before and during renal dialysis to prevent clotting of blood in the shunt. It is administered by intravenous injection.

Back  -    New Search

Epstein-Barr virus (EB virus, EBV) (ep-styn bar) n.

the virus, belonging to the herpesvirus group, that is the causative agent of glandular fever. It is also implicated in Burkitt's lymphoma, Hodgkin's disease, and hepatitis. [Sir M. A. Epstein (1921– ) and Y. M. Barr (1932– ), British pathologists]

Back  -    New Search

epulis (ep-yoo-lis) n.

a swelling on the gum.

Back  -    New Search

equi- prefix

denoting equality.

Back  -    New Search

equinia (i-kwin-i) n.

see GLANDERS.

Back  -    New Search

Erb's palsy (erbz) n.

weakness or paralysis of the shoulder and arm caused by injury to the upper roots of a baby's brachial plexus during birth. The muscles of the shoulder and the flexors of the elbow are paralysed and the arm hangs at the side internally rotated at the shoulder. [W. H. Erb (1840–1921), German neurologist]

Back  -    New Search

ERCP n.

endoscopic retrograde cholangio-pancreatography; a technique in which a catheter is passed through a duodenoscope into the ampulla of Vater of the common bile duct and injected with a radiopaque medium to outline the pancreatic duct and bile ducts radiologically.

Back  -    New Search

erectile (i-rek-tyl) adj.

capable of causing erection or becoming erect. The penis is composed largely of erectile tissue.

Back  -    New Search

erection (i-rek-shn) n.

the sexually active state of the penis, which becomes enlarged and rigid (due to the erectile tissue being swollen with blood). The term is also applied to the clitoris.

Back  -    New Search

erepsin (i-rep-sin) n.

a mixture of protein-digesting enzymes (see PEPTIDASE) secreted by the intestinal glands. It is part of the succus entericus.

Back  -    New Search

ERG n.

see ELECTRORETINOGRAPHY.

Back  -    New Search

erg- (ergo-) prefix

denoting work or activity.

Back  -    New Search

ergocalciferol (er-goh-kal-sif-er-ol) n.

see VITAMIN D.

Back  -    New Search

ergograph (er-g-grahf) n.

an apparatus for recording the work performed by the muscles of the body when undergoing activity.

Back  -    New Search

ergometrine (er-goh-met-reen) n.

a drug that stimulates contractions of the uterus. It is administered by injection to assist labour and to control bleeding following delivery. Trade name: Syntometrine .

Back  -    New Search

ergonomics (er-g-nom-iks) n.

the study of man in relation to his work and working surroundings.

Back  -    New Search

ergosterol (er-gos-ter-ol) n.

a plant sterol that, when irradiated with ultraviolet light, is converted to ergocalciferol (vitamin
D_2
). See VITAMIN D.

Back  -    New Search

ergot (er-got) n.

a fungus (Claviceps purpurea) that grows on rye. It produces several important alkaloids, including ergotamine and ergometrine. See also ERGOTISM.

Back  -    New Search

ergotamine (er-got--meen) n.

a drug that causes constriction of blood vessels and is used to relieve migraine. It is administered by mouth, injection, inhalation, or in suppositories. Trade names: Lingraine , Migril .

Back  -    New Search

ergotism (er-g-tizm) n.

poisoning caused by eating rye infected with the fungus ergot. The chief symptom is gangrene of the fingers and toes, with diarrhoea and vomiting, nausea, and headache.

Back  -    New Search

erogenous (i-roj-in-s) adj.

describing certain parts of the body, the physical stimulation of which leads to sexual arousal.

Back  -    New Search

erosion (i-roh-zhn) n.

an eating away of surface tissue by physical or chemical processes, including those associated with inflammation. cervical e. an abnormal area of epithelium that may develop at the cervix of the uterus due to tissue damage caused at childbirth or by attempts at abortion. dental e. loss of surface tooth substance, usually caused by repeated application of acid. It may result from excessive intake of citrus or carbonated drinks or citrus fruits or from regurgitation of acid from the stomach.

Back  -    New Search

erot- (eroto-) prefix

denoting sexual desire or love.

Back  -    New Search

eructation (i-ruk-tay-shn) n.

belching: the sudden raising of gas from the stomach.

Back  -    New Search

eruption (i-rup-shn) n.

1 the outbreak of a rash.

2 (in dentistry) the emergence of a growing tooth from the gum into the mouth.
Top

Back  -    New Search

erysipelas (e-ri-sip-ils) n.

a streptococcal infection of the skin, especially the face, characterized by redness and swelling. The affected areas usually have sharply defined margins, which can differentiate erysipelas from the otherwise similar cellulitis.

Back  -    New Search

erysipeloid (e-ri-sip-i-loid) n.

an infection of the skin and underlying tissues with the bacterium Erysipelothrix insidiosa, developing usually in people handling fish, poultry, or meat. It is normally confined to a finger or hand, which becomes reddened; sometimes systemic illness develops.

Back  -    New Search

erythema (e-ri-theem-) n.

flushing of the skin due to dilatation of the blood capillaries in the dermis. e. ab igne a reticular pigmented rash on the lower legs or elsewhere caused by persistent exposure to radiant heat. e. multiforme a condition characterized by so-called target lesions that may be recurrent and follow herpes simplex infection. e. nodosum a condition characterized by tender bruiselike swellings on the shins. It is often associated with streptococcal infection.

Back  -    New Search

erythr- (erythro-) prefix

denoting 1 redness.

2 erythrocytes.
Top

Back  -    New Search

erythraemia (e-ri-three-mi) n.

see POLYCYTHAEMIA (VERA).

Back  -    New Search

erythrasma (e-ri-thraz-m) n.

a chronic skin infection due to the bacterium Corynebacterium minutissimum, occurring in such areas as the armpits, where skin surfaces are in contact.

Back  -    New Search

erythroblast (i-rith-roh-blast) n.

any of a series of nucleated cells (see NORMOBLAST) that pass through a succession of stages of maturation to form red blood cells (erythrocytes). See also ERYTHROPOIESIS.

Back  -    New Search

erythroblastosis (i-rith-roh-blas-toh-sis) n.

the presence in the blood of erythroblasts. e. foetalis a severe but rare haemolytic anaemia affecting newborn infants due to destruction of the infant's red blood cells by factors present in the mother's serum. It is usually caused by incompatibility of the rhesus blood groups between mother and infant (see RHESUS FACTOR).

Back  -    New Search

erythrocyanosis (i-rith-roh-sy--noh-sis) n.

mottled purplish discoloration on the legs and thighs. The condition is worse in cold weather. Weight loss is the best treatment as it reduces the insulating effect of a thick layer of fat.

Back  -    New Search

erythrocyte (red blood cell) (i-rith-roh-syt) n.

a blood cell containing the pigment haemoglobin, the principal function of which is to transport oxygen. There are normally about
5 × 10^12
erythrocytes per litre of blood.

Back  -    New Search

erythrocyte sedimentation rate n.

see ESR.

Back  -    New Search

erythrocytosis (i-rith-roh-sy-toh-sis) n.

an increase in the number of red blood cells (erythrocytes) in the blood. See POLYCYTHAEMIA.

Back  -    New Search

erythroderma (exfoliative dermatitis) (i-rith-roh-der-m) n.

abnormal reddening, flaking, and thickening of the skin affecting a wide area of the body.

Back  -    New Search

erythroedema (i-rith-ri-dee-m) n.

see PINK DISEASE.

Back  -    New Search

erythrogenesis (i-rith-roh-jen-i-sis) n.

see ERYTHROPOIESIS.

Back  -    New Search

erythromycin (i-rith-roh-my-sin) n.

an antibiotic used to treat infections caused by a wide range of bacteria and other microorganisms. It is administered by mouth or injection. Trade names: Erymax , Erythrocin .

Back  -    New Search

erythropenia (i-rith-roh-pee-ni) n.

a reduction in the number of red blood cells (erythrocytes) in the blood.

Back  -    New Search

erythroplasia (i-rith-roh-play-zi) n.

an abnormal red patch of skin that occurs in the mouth or on the genitalia and is precancerous.

Back  -    New Search

erythropoiesis (erythrogenesis) (i-rith-roh-poi-ee-sis) n.

the process of red blood cell (erythrocyte) production, which normally occurs in the blood-forming tissue of the bone marrow. See also HAEMOPOIESIS.

Back  -    New Search

erythropoietin (haemopoietin) (i-rith-roh-poi--tin) n.

a hormone secreted by certain cells in the kidney in response to a reduction in the amount of oxygen reaching the tissues. Erythropoietin increases and controls the rate of red cell production (erythropoiesis).

Back  -    New Search

erythropsia (e-ri-throp-si) n.

red vision: a symptom sometimes experienced after removal of a cataract and also in snow blindness.

Back  -    New Search

Esbach's albuminometer (ess-bahks) n.

a graduated glass tube used for measuring the amount of albumin in a specimen of urine. [G. H. Esbach (1843–90), French physician]

Back  -    New Search

eschar (ess-kar) n.

a scab or slough, as produced by the action of heat or a corrosive substance on living tissue.

Back  -    New Search

Escherichia (esh-er-ik-i) n.

a genus of Gram-negative, generally motile, rodlike bacteria that are found in the intestines of man and many animals. E. coli a species that is usually not harmful but some strains of which cause gastrointestinal infections. E. coli 0157 is a pathogenic serotype causing colitis, which may give rise to the complications of haemolytic uraemic syndrome or thrombocytopenic purpura.

Back  -    New Search

eserine (ess-er-een) n.

see PHYSOSTIGMINE.

Back  -    New Search

Esmarch's bandage (ess-marks) n.

a rubber or elastic bandage that is wound tightly around a limb in order to force blood out from an area in which an operation is to be performed in a blood-free field. [J. F. A. von Esmarch (1823–1908), German surgeon]

Back  -    New Search

esotropia (ess-oh-troh-pi) n.

convergent strabismus: a type of squint.

Back  -    New Search

espundia (mucocutaneous leishmaniasis) (ess-puun-di) n.

a disease of the skin and mucous membranes caused by the parasitic protozoan Leishmania braziliensis (see LEISHMANIASIS), occurring in South and Central America.

Back  -    New Search

ESR (erythrocyte sedimentation rate) n.

the rate at which red blood cells (erythrocytes) settle out of suspension in blood plasma, measured under standardized conditions. The ESR increases in rheumatic diseases, chronic infections, and malignant disease, and thus provides a valuable screening test for these conditions.

Back  -    New Search

essence (ess-ns) n.

a solution consisting of an essential oil dissolved in alcohol.

Back  -    New Search

essential (i-sen-shl) adj.

describing a disorder that is not apparently attributable to an outside cause.

Back  -    New Search

essential amino acid n.

an amino acid that is essential for normal growth and development but cannot be synthesized by the body and must therefore be obtained from protein in the diet. See AMINO ACID.

Back  -    New Search

essential fatty acid n.

one of a group of unsaturated fatty acids that are essential for growth but cannot be synthesized by the body. The essential fatty acids are linoleic acids , linolenic acids , and arachidonic acids .

Back  -    New Search

essential oil n.

a volatile oil derived from an aromatic plant. Essential oils are used in various pharmaceutical preparations. See also AROMATHERAPY.

Back  -    New Search

ESWL n.

extracorporeal shock-wave lithotripsy. See LITHOTRIPSY.

Back  -    New Search

ethacrynic acid (eth--krin-ik) n.

a diuretic administered by mouth or injection to treat fluid retention (oedema), such as that associated with heart failure and kidney and liver disorders. Trade name: Edecrin .

Back  -    New Search

ethambutol (eth-am-bew-tol) n.

a drug administered by mouth in the treatment of tuberculosis, in conjunction with other drugs. Trade name: Myambutol .

Back  -    New Search

ethanol (ethyl alcohol) (eth--nol) n.

see ALCOHOL.

Back  -    New Search

ether (ee-ther) n.

a volatile liquid formerly used as an anaesthetic administered by inhalation. It also has laxative action when administered by mouth.

Back  -    New Search

ethical committee (eth-ikl) n.

(in Britain) a group of lay people, medical practitioners, and other experts set up (especially in a hospital) to monitor investigations, concerned with teaching or research, that involve the use of human subjects.

Back  -    New Search

ethics (eth-iks) n.

a code of principles governing correct behaviour, which in the nursing profession includes behaviour towards patients and their families, visitors, and colleagues.

Back  -    New Search

ethinyloestradiol (eth-i-nyl-ee-str-dy-ol) n.

a synthetic female sex hormone (see OESTROGEN) administered by mouth to treat symptoms of the menopause and to suppress lactation. It is mainly used in oral contraceptives.

Back  -    New Search

ethionamide (eth-ee-on-a-myd) n.

a drug used to treat tuberculosis, usually in conjunction with other drugs. It is administered by mouth or in suppositories. Trade name: Trescatyl .

Back  -    New Search

ethisterone (eth-iss-ter-ohn) n.

a synthetic female sex hormone (see PROGESTOGEN) administered by mouth to treat menstrual disorders, particularly amenorrhoea.

Back  -    New Search

ethmoid bone (eth-moid) n.

a bone in the floor of the cranium that contributes to the nasal cavity and orbits. The part of the ethmoid forming the roof of the nasal cavity (the cribriform plate ) is pierced with many small holes through which the olfactory nerves pass. See also NASAL (CONCHA), SKULL.

Back  -    New Search

ethnology (eth-nol-ji) n.

the study of the different races of mankind, concerned mainly with cultural and social differences between groups and the problems that arise from their particular ways of life.
—ethnic (eth-nik) adj.

Back  -    New Search

ethosuximide (eth-oh-suks-i-myd) n.

an anticonvulsant drug administered by mouth to control epileptic seizures. Trade names: Emeside , Zarontin .

Back  -    New Search

ethyl chloride (chloroethane) n.

a volatile liquid used chiefly as a local anaesthetic applied topically to the skin before minor surgery. Formula:
C_2H_5Cl
.

Back  -    New Search

ethyloestrenol (eth-il-ee-str-nol) n.

a steroid drug with anabolic properties, administered by mouth to treat conditions involving wasting of protein and bone, such as osteoporosis. Trade name: Orabolin .

Back  -    New Search

ethynodiol (eth-l-noh-dy-ol) n.

a synthetic female sex hormone (see PROGESTOGEN) that is used to treat menstrual disorders and in oral contraceptives. It is administered by mouth, usually in combination with an oestrogen. Trade name: Femulen .

Back  -    New Search

etidronate (et-i-droh-nayt) n.

see BIPHOSPHONATES.

Back  -    New Search

etiology (ee-ti-ol-ji) n.

see AETIOLOGY.

Back  -    New Search

etoposide (VP16–213) (e-top-oh-syd) n.

a cytotoxic drug derived from an extract of the mandrake plant. It is administered intravenously or by mouth, primarily in the treatment of bronchial carcinoma, lymphomas, and testicular tumours. Trade name: Vepesid .

Back  -    New Search

eu- prefix

denoting 1 good, well, or easy.

2 normal.
Top

Back  -    New Search

eucalyptol (yoo-k-lip-tol) n.

a volatile oil that has a mild irritant effect on the mucous membranes of the mouth and digestive system. It is taken as pastilles or inhaled as vapour to relieve catarrh.

Back  -    New Search

eugenics (yoo-jen-iks) n.

the science that is concerned with the improvement of the human race by means of the principles of genetics.

Back  -    New Search

eumenorrhoea (yoo-men--ree-) n.

regular menstruation. This does not necessarily indicate regular ovulation.

Back  -    New Search

eunuch (yoo-nk) n.

a male who has undergone castration.

Back  -    New Search

eupepsia (yoo-pep-si) n.

the state of normal or good digestion.

Back  -    New Search

euphoria (yoo-for-i) n.

a state of cheerfulness and well-being. A morbid degree of euphoria is characteristic of mania and hypomania. See also ECSTASY, ELATION.

Back  -    New Search

euplastic (yoo-plast-ik) adj.

describing a tissue that heals quickly after injury.

Back  -    New Search

Eustachian tube (pharyngotym-panic tube) (yoo-stay-shn) n.

the tube that connects the middle ear to the pharynx. It allows the pressure on the inner side of the eardrum to remain equal to the external pressure. [B. Eustachio (1520 –74), Italian anatomist].

Back  -    New Search

euthanasia (yooth-n-ay-zi) n.

the act of taking life to relieve suffering. active e. euthanasia achieved by active steps, usually the administration of a drug. passive e. euthanasia achieved by the deliberate withholding of treatment that might prevent death. voluntary e. euthanasia produced at the request of the patient.

Back  -    New Search

euthyroid (yoo-th'y-roid) adj.

having a normally functioning thyroid gland. Compare HYPERTHYROIDISM, HYPOTHYROIDISM.
—euthyroidism n.

Back  -    New Search

evacuation (i-vak-yoo-ay-shn) n.

removal of the contents of a cavity, especially the emptying of the bowels (defecation).

Back  -    New Search

evacuator (i-vak-yoo-ay-ter) n.

a device for sucking fluid out of a cavity. Evacuators may be used to empty the bladder of unwanted material during such operations as the removal of a calculus or transurethral prostatectomy.

Back  -    New Search

evaluation (i-val-yoo-ay-shn) n.

the final stage of the nursing process, in which the effects of nursing interventions are compared with the goals or objectives set in the care plan. See EXPECTED OUTCOME.

Back  -    New Search

eventration (ee-ven-tray-shn) n.

1 protrusion of the intestines through the abdominal wall.

2 abnormal elevation of part of the diaphragm due to a congenital weakness.
Top

Back  -    New Search

eversion (i-ver-shn) n.

a turning outward. e. of the cervix a condition in which the edges of the neck (cervix) of the uterus turn outward after having been torn during childbirth.

Back  -    New Search

evisceration (i-vis-er-ay-shn) n.

1 (in surgery)
a the removal of part of the viscera.
b the protrusion of an organ through a surgical incision.

2 (in ophthalmology) an operation in which the contents of the eyeball are removed, the empty outer envelope (sclera) being left behind. Compare ENUCLEATION.
Top

Back  -    New Search

Ewing's tumour (Ewing's sarcoma) (yoo-ingz) n.

a malignant bone tumour arising in the bone marrow. It usually affects the femur but is liable to spread to other bones and to the lung. It is most common in children and adolescents. [J. Ewing (1866 –1943), US pathologist].

Back  -    New Search

ex- (exo-) prefix

denoting outside or outer.

Back  -    New Search

exacerbation (eks-ass-er-bay-shn) n.

an increase in the severity of a disorder, marked by an increase in the intensity of its symptoms and signs.

Back  -    New Search

exaltation (eg-zawl-tay-shn) n.

see ELATION.

Back  -    New Search

exanthem (eks-anth-m) n.

a rash or eruption, such as that occurring in measles. e. subitum see ROSEOLA (INFANTUM).
—exanthematous (eks-an-th'em-ts) adj.

Back  -    New Search

exchange transfusion (iks-chaynj) n.

a technique for treating haemolytic disease in newborn infants. Blood is withdrawn from the baby (via the umbilical vein) and replaced by an equal amount of donor blood compatible with the mother's blood.

Back  -    New Search

excimer laser (ek-sy-mer) n.

see LASER.

Back  -    New Search

excise (ek-syz) vb.

to cut out tissue, an organ, or a tumour from the body.
—excision (ek-si-zhn) n.

Back  -    New Search

excitation (eks-i-tay-shn) n.

(in neurophysiology) the triggering of a conducted impulse in the membrane of a muscle cell or nerve fibre.

Back  -    New Search

excoriation (iks-kor-i-ay-shn) n.

the destruction and removal of the surface of the skin or the covering of an organ by scraping, the application of a chemical, or other means.

Back  -    New Search

excrescence (fiks-kress-ns) n.

an abnormal outgrowth on the surface of the body, such as a wart.

Back  -    New Search

excreta (iks-kree-t) n.

any waste material discharged from the body, especially faeces.

Back  -    New Search

excretion (iks-kree-shn) n.

the removal of the waste products of metabolism from the body, mainly through the action of the kidneys. Excretion also includes the loss of water, salts, etc. through the sweat glands, the loss of carbon dioxide and water vapour from the lungs, and the egestion of faeces.

Back  -    New Search

exenteration (eks-en-ter-ay-shn) n.

(in ophthalmology) an operation in which all the contents of the eye socket (orbit) are removed, leaving only the bony walls intact.

Back  -    New Search

exercise (eks-er-syz) n.

any activity resulting in physical exertion that is intended to maintain physical fitness, to condition the body, or to correct a physical deformity. Exercises may be done actively by the person or passively by a therapist. aer-obic e. an exercise intended to increase oxygen consumption (as in running) and to benefit the lungs and cardiovascular system. isometric e. an exercise in which the muscles contract but there is no movement; this is induced when a limb is made to push against something rigid and is designed to improve muscle tone. iso-tonic e. an exercise in which the muscles contract and there is movement, but the force remains the same; this improves joint mobility and muscle strength.

Back  -    New Search

exfoliation (eks-foh-li-ay-shn) n.

1 flaking off of the upper layers of the skin.

2 separation of a surface epithelium from the underlying tissue.
Top

3 the natural shedding of primary teeth.
Top

—exfoliative adj.

Back  -    New Search

exhalation (expiration) (eks-h-lay-shn) n.

the act of breathing air from the lungs out through the mouth and nose.

Back  -    New Search

exhibitionism (eksi-bish-n-izm) n.

exposure of the genitals to another person, as a sexually deviant act. The word is often broadened to mean public flaunting of any quality of the individual.

Back  -    New Search

exo- prefix

see EX-.

Back  -    New Search

exocrine gland (eks-oh-kryn) n.

a gland that discharges its secretion by means of a duct, which opens onto an epithelial surface. Examples of exocrine glands are the sebaceous and sweat glands. See also SECRETION.

Back  -    New Search

exogenous (ek-soj-in-s) adj.

originating outside the body or part of the body: applied particularly to substances in the body that are derived from the diet rather than built up by the body's own processes of metabolism. Compare ENDOGENOUS.

Back  -    New Search

exomphalos (ek-som-f-ls) n.

an umbilical hernia.

Back  -    New Search

exophthalmic goitre (Graves's disease) (eks-off-thal-mik) n.

see THYROTOXICOSIS.

Back  -    New Search

exophthalmos (eks-off-thal-mos) n.

protrusion of the eyeballs in their sockets. This can result from injury or disease of the eyeball or socket but is most commonly associated with overactivity of the thyroid gland (see THYROTOXICOSIS).
—ex-ophthalmic adj.

Back  -    New Search

exostosis (eks-os-toh-sis) n.

a benign outgrowth of bone with a cap of cartilage, arising from the surface of a bone. See OSTEOMA.

Back  -    New Search

exotic (ig-zot-ik) adj.

describing a disease occurring in a region of the world far from where it might be expected.

Back  -    New Search

exotoxin (eks-oh-toks-in) n.

a highly potent poison, often harmful to only a limited range of tissues, that is produced by a bacterial cell and secreted into its surrounding medium. Exotoxins are produced by the bacteria causing botulism, diphtheria, and tetanus. Compare ENDO-TOXIN.

Back  -    New Search

exotropia (eks-oh-troh-pi) n.

divergent strabismus: a type of squint.

Back  -    New Search

expected outcome (iks-pekt-id) n.

a statement in the care plan of what the nursing intervention is intended to achieve, usually described in terms of the patient's expected behaviour. See BEHAVIOURAL OBJECTIVE.

Back  -    New Search

expectorant (iks-pek-ter-nt) n.

a drug that enhances the secretion of sputum by the air passages so that it is easier to cough up. Expectorants are used in cough mixtures; they act by increasing the bronchial secretion or make it less viscous (see MUCOLYTIC).

Back  -    New Search

expectoration (iks-pek-ter-ay-shn) n.

the act of spitting out material brought into the mouth by coughing.

Back  -    New Search

experiential learning (iks-peer-i-en-shl) n.

learning by experiencing a situation or a simulated situation, as in role playing, and then reflecting on that experience.

Back  -    New Search

expiration (eks-per-ay-shn) n.

1 the act of breathing out air from the lungs: exhalation.

2 dying.
Top

Back  -    New Search

explant (eks-plahnt)

1 n. live tissue transferred from the body (or any organism) to a suitable artificial medium for culture.

2 vb. to transfer live tissue for culture outside the body.
Top

—explantation n.

Back  -    New Search

exploration (eks-pl-ray-shn) n.

(in surgery) an investigative operation on a wound, tissue, or cavity to determine the cause of symptoms.
—exploratory (iks-plo-r-ter-i) adj.

Back  -    New Search

exposure (iks-poh-zher) n.

(in behaviour therapy) a method of treating fears and phobias that involves confronting the individual with the feared object or situation, either gradually (see DESENSITIZATION, GRADED SELF-EXPOSURE) or suddenly (see FLOODING).

Back  -    New Search

expression (iks-presh-n) n.

1 the appearance of the face, reflecting the individual's physical or emotional state.

2 expulsion by pressing or squeezing, as of milk from the breast after pregnancy or the fetus or placenta from the uterus at childbirth.
Top

Back  -    New Search

exsanguination (iks-sang-win-ay-shn) n.

1 depriving the body of blood; for example, as a result of an accident causing severe bleeding.

2 a technique for providing a bloodless field to facilitate certain operative procedures.
Top

—exsanguinate vb.

Back  -    New Search

exsufflation (eks-suf-lay-shn) n.

the forcible removal of secretions from the air passages by some form of suction apparatus.

Back  -    New Search

extended role (enhanced role) (iks-ten-did) n.

(of the nurse) activities concerned with patients, either in hospital or the community, that are appropriate for delegation by doctors to nurses. Agreement on the delegated responsibilities is reached locally by consultation between medical and nursing professions.

Back  -    New Search

extension (iks-ten-shn) n.

1 the act of extending or stretching, especially the muscular movement by which a limb is straightened.

2 the application of traction to a fractured or dislocated limb in order to restore it to its normal position.
Top

Back  -    New Search

extensor (iks-ten-ser) n.

any muscle that causes the straightening of a limb or other part.

Back  -    New Search

exteriorization (iks-teer-i-er-l-zay-shn) n.

a surgical procedure in which an organ is brought from its normal site to the surface of the body, as in colostomy.

Back  -    New Search

exteroceptor (eks-ter-oh-sep-ter) n.

a sensory nerve, ending in the skin or a mucous membrane, that is responsive to stimuli from outside the body. See also CHEMORECEPTOR, RECEPTOR.

Back  -    New Search

extinction (iks-tink-shn) n.

(in psychology) the weakening of a conditioned reflex that takes place if it is not maintained by reinforcement.

Back  -    New Search

extirpation (eks-ter-pay-shn) n.

the complete surgical removal of tissue, an organ, or a growth.

Back  -    New Search

extra- prefix

denoting outside or beyond.

Back  -    New Search

extracapsular (eks-tr-kaps-yoo-ler) adj.

outside or not involving a capsule. e. extraction surgical removal of a cataract in which the capsule of the lens is left behind. e. fracture a fracture, especially of the hip, that does not involve the joint capsule.

Back  -    New Search

extracellular (eks-tr-sel-yoo-ler) adj.

situated or occurring outside cells. e. fluid the fluid surrounding cells.

Back  -    New Search

extracorporeal (eks-tr-kor-por-il) adj.

situated or occurring outside the body. e. circulation the circulation of the blood outside the body, as through a heart-lung machine or an artificial kidney (see HAEMODIALYSIS). e. membrane oxygenation (ECMO) a rescue treatment for otherwise fatal respiratory failure in newborn babies or infants due to prematurity or overwhelming septicaemia. It involves prolonged cariopulmonary bypass to support gas exchange.

Back  -    New Search

extract (eks-trakt) n.

a preparation containing the pharmacologically active principles of a drug, made by evaporating a solution of the drug in water, alcohol, or ether.

Back  -    New Search

extraction (iks-trak-shn) n.

1 the surgical removal of a part of the body. Extraction of teeth is usually achieved by applying extraction forceps to the crown or root of the tooth to dislocate it from its socket.

2 the act of pulling out a baby from the body of its mother during childbirth.
Top

Back  -    New Search

extradural (eks-tr-dewr-l) adj.

see EPIDURAL.

Back  -    New Search

extraembryonic membranes (eks-tr-em-bree-on-ik) pl. n

the membranous structures that surround the embryo and contribute to the placenta and umbilical cord. They include the amnion, chorion, allantois, and yolk sac.

Back  -    New Search

extrapleural (eks-tr-ploor-l) adj.

relating to the tissues of the chest wall outside the parietal pleura.

Back  -    New Search

extrapyramidal system (eks-tr-pi-ram-i-d'l) n.

the system of nerve tracts and pathways connecting the cerebral cortex, basal ganglia, thalamus, cerebellum, reticular formation, and spinal neurones in complex circuits not included in the pyramidal system. The extrapyramidal system is mainly concerned with the regulation of stereotyped reflex muscular movements.

Back  -    New Search

extrasystole (eks-tr-sis-t-li) n.

see ECTOPIC BEAT.

Back  -    New Search

extrauterine (eks-tr-yoo-teryn) adj.

outside the uterus.

Back  -    New Search

extravasation (iks-trav--say-shn) n.

the leakage and spread of blood or fluid from vessels into the surrounding tissues, which follows injury, burns, inflammation, and allergy.

Back  -    New Search

extraversion (eks-tr-ver-shn) n.

see EXTROVERSION.

Back  -    New Search

extrinsic factor (eks-trin-sik) n.

an old name for vitamin
B^12
.

Back  -    New Search

extrinsic muscle n.

a muscle, such as any of those controlling movements of the eyeball, that has its origin some distance from the part it acts on.

Back  -    New Search

extroversion (eks-tr-ver-shn) n.

1 (or extraversion) an enduring personality trait characterized by interest in the outside world rather than the self. People high in extroversion (extroverts ) are gregarious and outgoing, prefer to change activities frequently, and are not susceptible to permanent conditioning. Compare INTROVERSION.

2 a turning inside out of a hollow organ, such as the uterus (which sometimes occurs after childbirth).
Top

Back  -    New Search

extrovert (eks-tr-vert) n.

see EXTROVERSION.

Back  -    New Search

exudation (eks-yoo-day-shn) n.

the slow escape of liquid (the exudate ) containing proteins and white cells through the walls of intact blood vessels, usually as a result of inflammation. Exudation is a normal part of the body's defence mechanisms.

Back  -    New Search

eye (I) n.

the organ of sight: a three-layered roughly spherical structure specialized for receiving and responding to light (see illustration). Light enters the eye through the cornea, which refracts it through the aqueous humour onto the lens. By accommodation light is focused through the vitreous humour onto the retina. Here light-sensitive cells (see CONE, ROD) send nerve impulses to the brain via the optic nerve.

Back  -    New Search

eyeball (I-bawl) n.

the body of the eye, which is roughly spherical, is bounded by the sclera, and lies in the orbit. Its movements are controlled by three pairs of extrinsic eye muscles.

Back  -    New Search

eyelid (I-lid) n.

the protective covering of the eye. Each eye has two eyelids consisting of skin, muscle, connective tissue (tarsus ), and sebaceous glands (meibomian glands or tarsal glands ). Each eyelid is lined with membrane (see CONJUNCTIVA) and fringed with eyelashes. Anatomical names: blepharon , palpebra .

Back  -    New Search

eyestrain (I-strayn) n.

a sense of fatigue brought on by use of the eyes for prolonged close work or in persons who have an uncorrected error of refraction.
Symptoms are usually aching or burning of the eyes, accompanied by headache. Medical name: asthenopia .

Back  -    New Search

eye tooth n.

see CANINE.

Back  -    New Search

F

F

1 abbreviation for Fahrenheit.

2 symbol for farad.
Top

Back  -    New Search

face-lift (fays-lift) n.

plastic surgery designed to correct sagging facial tissues. Eyelid drooping can be corrected at the same procedure.

Back  -    New Search

facet (fas-it) n.

a small flat surface on a bone, especially a surface of articulation.

Back  -    New Search

facet syndrome n.

a syndrome caused by dislocation of the articulating surface of the vertebrae, resulting in pain and muscle spasm.

Back  -    New Search

facial nerve (fay-shl) n.

the seventh cranial nerve (VII): a mixed sensory and motor nerve that supplies the muscles of facial expression, the taste buds of the front part of the tongue, the sublingual salivary glands, and the lacrimal glands.

Back  -    New Search

-facient suffix

denoting causing or making.

Back  -    New Search

facies (fay-shi-eez) n.

facial expression, often a guide to a patient's state of health as well as his emotions. adenoid f. the vacant look, with the mouth drooping open, seen in adenoids. Hippocratic f. the sallow face, sagging and with listless staring eyes, that some read as the expression of approaching death.

Back  -    New Search

Factor VIII (antihaemophilic factor) (fak-ter) n.

a coagulation factor normally present in blood. Deficiency of the factor, which is inherited by males from their mothers, results in classic haemophilia.

Back  -    New Search

Factor IX (Christmas factor) n.

a coagulation factor normally present in the blood. Deficiency of the factor results in classic haemophilia.

Back  -    New Search

Factor XI n.

a coagulation factor normally present in blood. Deficiency of the factor is inherited, but rarely causes spontaneous bleeding. However, bleeding does occur after surgery or trauma to the blood vessels.

Back  -    New Search

Factory Inspectorate (fak-ter-i in-spek-ter-it) n.

a statutory body responsible for monitoring the health and safety of factory workers. It is administered by the Department of Employment through the Health and Safety Executive under the terms of the Health and Safety at Work Act.

Back  -    New Search

facultative (fak-l-t-tiv) adj.

describing an organism, such as a parasite, that is not restricted to one way of life. Compare OBLIGATE.

Back  -    New Search

faecalith (fee-ka-lith) n.

a small hard mass of faeces, found particularly in the vermiform appendix: a cause of inflammation.

Back  -    New Search

faeces (fee-seez) n.

the waste material that is eliminated through the anus. It is formed in the colon and consists of a solid or semisolid mass of undigested food remains (chiefly cellulose) mixed with bile pigments (which are responsible for the colour), bacteria, various secretions (e.g. mucus), and some water.
—faecal (fee-kl) adj.

Back  -    New Search

Fahrenheit temperature (fa-rn-hyt) n.

temperature expressed on a scale in which the melting point of ice is assigned a temperature of 32° and the boiling point of water a temperature of 212°. The formula for converting from Fahrenheit (F) to Celsius (C) is: C = 5/9(F - 32). See also CELSIUS TEMPERATURE. [G. D. Fahrenheit (1686–1736), German physicist]

Back  -    New Search

failure to thrive (FTT) (fayl-yer t thryv) n.

failure of an infant to grow satisfactorily compared with the average for that community. It is detected by regular measurements and plotting on centile charts. It can be the first indication of a serious underlying condition, such as kidney or heart disease or malabsorption, or it may result from problems at home, particularly nonaccidental injury.

Back  -    New Search

fainting (faynt-ing) n.

see SYNCOPE.

Back  -    New Search

Fairbank's splint (fair-banks) n.

a splint used for the correction of Erb's palsy in infants. It immobilizes the affected arm with the shoulder abducted and externally rotated, the elbow bent at 90°, and the forearm and wrist held in a supine position. [T. J. Fairbank , British orthopaedic surgeon]

Back  -    New Search

falciform ligament (fal-si-form) n.

a fold of peritoneum separating the right and left lobes of the liver and attaching it to the diaphragm and the anterior abdominal wall as far as the umbilicus.

Back  -    New Search

Fallopian tube (oviduct, uterine tube) (f-loh-pin) n.

either of a pair of tubes that conduct ova from the ovary to the uterus (see REPRODUCTIVE SYSTEM). The ovarian end opens into the abdominal cavity via a funnel-shaped structure with fimbriae surrounding the opening. The ovum is fertilized near the ovarian end of the tube. [G. Fallopius (1523–63), Italian anatomist]

Back  -    New Search

falloposcope (f-loh-poh-skohp) n.

a narrow flexible fibreoptic endoscope used to view the inner lining of the Fallopian tubes.
—falloposcopy n.

Back  -    New Search

Fallot's tetralogy (fal-ohz) n.

see TETRALOGY OF FALLOT.

Back  -    New Search

falx (falx cerebri) (falks) n.

a sickleshaped fold of the dura mater that dips inwards from the skull in the midline, between the cerebral hemispheres.

Back  -    New Search

familial (f-mil-il) adj.

describing a condition or character that is found in some families but not in others. It is often inherited. f. adenomatous polyposis see POLYPOSIS.

Back  -    New Search

Family Health Services Authority (FHSA) (fam-ili) n.

(in Britain) a former authority responsible for running general medical services for a given population. See HEALTH AUTHORITY.

Back  -    New Search

family planning n.

1 the use of contraception to limit or space out the numbers of children born to a couple.

2 provision of contraceptive methods within a community or nation.
Top

Back  -    New Search

family therapy n.

a form of psychotherapy in which all family members are seen together in order to clarify and modify the ways they relate together.

Back  -    New Search

famotidine (fam-oh-ti-deen) n.

a drug used for the treatment of duodenal ulcers and conditions of excessive gastric acid secretion, such as the Zollinger-Ellison syndrome. It is administered by mouth and intravenously. Trade name: Pepcid .

Back  -    New Search

Fanconi syndrome (fan-koh-ni) n.

a disorder of the proximal kidney tubules, which may be inherited or acquired and is most common in children. It is characterized by the urinary excretion of large amounts of amino acids, glucose, and phosphates. Symptoms may include osteomalacia, rickets, muscle weakness, and cystinosis. [G. Fanconi (1892–1979), Swiss paediatrician]

Back  -    New Search

fantasy (fan-t-si) n.

a complex sequence of imagination in which several imaginary elements are woven together into a story. An excessive preoccupation with one's own imaginings may be symptomatic of a difficulty in coping with reality.

Back  -    New Search

farad (fa-rd) n.

the SI unit of capacitance, equal to the capacitance of a capacitor between the plates of which a potential difference of 1 volt appears when it is charged with 1 coulomb of electricity. Symbol: F.

Back  -    New Search

faradism (fa-r-dizm) n.

the use of induced rapidly alternating electric currents to stimulate nerve and muscle activity. See also ELECTROTHERAPY.

Back  -    New Search

farcy (far-si) n.

see GLANDERS.

Back  -    New Search

farinaceous (fa-ri-nay-shs) adj.

starchy; describing foods rich in starch (e.g. flour, bread, cereals) or diets based on these foods.

Back  -    New Search

farmer's lung (far-merz) n.

an occupational lung disease caused by allergy to fungal spores that grow in inadequately dried stored hay, straw, or grain, which then becomes mouldy. An acute reversible form can develop a few hours after exposure; a chronic form, with the gradual development of irreversible breathlessness, occurs with or without preceding acute attacks.

Back  -    New Search

fascia (fash-i) n. (pl. fasciae)

connective tissue that forms sheaths for muscles and protective layers surrounding the softer or more delicate organs immediately beneath the skin.

Back  -    New Search

fasciculation (f-sik-yoo-lay-shn) n.

brief spontaneous contraction of a few muscle fibres, which is seen as a flicker of movement under the skin. It is most often associated with disease of the lower motor neurones (e.g. motor neurone disease).

Back  -    New Search

fasciculus (fascicle) (f-sik-yoo-ls) n.

a bundle, e.g. of nerve or muscle fibres.

Back  -    New Search

fasciitis (fash-i-l-tis) n.

inflammation of fascia. It may result from bacterial infection or from a rheumatic disease, such as Reiter's syndrome or ankylosing spondylitis. See NECROTIZING FASCIITIS, PLANTAR FASCIITIS.

Back  -    New Search

Fasciola (fas-i-oh-l) n.

a genus of flukes. F. hepatica the liver fluke, which normally lives as a parasite of sheep and other herbivorous animals but sometimes infects man (see FASCIOLIASIS).

Back  -    New Search

fascioliasis (fas-i-oh-ly--sis) n.

an infestation of the bile ducts and liver with the liver fluke, Fasciola hepatica. Symptoms include fever, dyspepsia, vomiting, loss of appetite, abdominal pain, and coughing; the liver may also be extensively damaged.

Back  -    New Search

fastigium (fas-tij-im) n.

the highest point of a fever.

Back  -    New Search

fat (neutral fat) (fat) n.

a substance that consists chiefly of triglycerides and is the principal form in which energy is stored by the body (see ADIPOSE TISSUE). It also serves as an insulating material beneath the skin and around certain organs. See also BROWN FAT; FATTY ACID; LIPID.

Back  -    New Search

fatigue (f-teeg) n.

1 mental or physical tiredness, following prolonged or intense activity. Muscle fatigue may be due to the waste products of metabolism accumulating in the muscles faster than they can be removed by the venous blood.

2 the inability of an organism, an organ, or a tissue to give a normal response to a stimulus until a certain recovery period has elapsed.
Top

Back  -    New Search

fatty acid (fat-i) n.

an organic acid such as oleic acid or stearic acid. Fatty acids are the fundamental constituents of many important lipids, including triglycerides. Some fatty acids can be synthesized by the body; others (see ESSENTIAL FATTY ACID) must be obtained from the diet. See also FAT.

Back  -    New Search

fatty degeneration n.

deterioration in the health of a tissue due to the deposition of abnormally large amounts of fat in its cells. It may be caused by incorrect diet, excessive alcohol consumption, or a shortage of oxygen in the tissues.

Back  -    New Search

fauces (faw-seez) n.

the opening leading from the mouth into the pharynx. It is surrounded by the glossopalatine arch (which forms the anterior pillars of the fauces) and the pharyngopalatine arch (the posterior pillars).

Back  -    New Search

favism (fay-vizm) n.

an inherited defect in the enzyme glucose-6-phosphate dehydrogenase causing the red blood cells to become sensitive to a chemical in broad beans. It results in destruction of red blood cells (haemolysis), which may lead to severe anaemia, requiring blood transfusion. Favism occurs in parts of the Mediterranean and Iran. See also GLUCOSE-6-PHOSPHATE DEHYDROGENASE DEFICIENCY.

Back  -    New Search

favus (fay-vs) n.

a type of ringworm of the scalp, caused by the fungus Trichophyton schoenleinii. Favus, which is rare in Europe, is typified by yellow crusts forming honeycomb-like masses.

Back  -    New Search

fear (feer) n.

an emotional state evoked by threat of danger. It is usually characterized by unpleasant subjective experiences; physiological changes, such as increased heart rate and sweating; and behavioural changes, such as avoidance of fear-producing objects or situations. See also PHOBIA.

Back  -    New Search

febricula (fi-brik-yoo-l) n.

a fever of low intensity or short duration.

Back  -    New Search

febrifuge (feb-ri-fewj) n.

a treatment or drug that reduces or prevents fever. See ANTIPYRETIC.

Back  -    New Search

febrile (fee-bryl) adj.

relating to or affected with fever.

Back  -    New Search

feedback (feed-bak) n.

the coupling of the output of a process to the input. Feedback mechanisms are important in regulating many physiological processes; for example, hormone output and enzyme-mediated reactions.

Back  -    New Search

Fehling's test (fay-lingz) n.

a test used for detecting the presence of sugar in urine; it has now been replaced by better and easier methods. [H. von Fehling (1812–85), German chemist]

Back  -    New Search

Felty's syndrome (fel-tiz) n.

enlargement of the spleen (see HYPERSPLENISM) associated with rheumatoid arthritis, characterized by a decrease in the numbers of white blood cells and frequent infections. [A. R. Felty (1895–1964), US physician]

Back  -    New Search

feminization (fem-i-ny-zay-shn) n.

the development of female secondary sexual characteristics (enlargement of the breasts, loss of facial hair, and fat beneath the skin) in the male, either as a result of an endocrine disorder or of hormone therapy.

Back  -    New Search

femoral (fem-er-l) adj.

of or relating to the thigh or to the femur. f. artery an artery arising from the external iliac artery. It runs down the front medial aspect of the thigh, passing into the back of the thigh two-thirds of the way down. f. epiphysis the growth area of the upper end of the femur; partial dislocation leads to deformity of the head of the bone and premature degeneration of the hip joint. f. neck the narrowed end of the femur, which carries the head: the commonest site of fracture of the leg in elderly women. f. nerve the nerve that supplies the quadriceps muscle at the front of the thigh and receives sensation from the front and inner sides of the thigh. f. triangle (Scarpa's triangle ) a triangular depression on the inner side of the thigh bounded by the sartorius and adductor longus muscles and the inguinal ligament. The pulse can be felt here as the femoral artery lies over the depression.

Back  -    New Search

femur (thigh bone) (fee-mer) n.

a long bone between the hip and the knee. The head of the femur articulates with the acetabulum of the hip bone; the lower end articulates with the tibia.

Back  -    New Search

fenbufen (fen-bew-fn) n.

an anti-inflammatory drug (see NSAID) used to relieve inflammation and the resulting pain and stiffness. It is administered by mouth. Trade name: Lederfen .

Back  -    New Search

fenestra (fi-nes-tr) n.

(in anatomy) an opening resembling a window. f. ovalis (f. vestibuli ) the opening between the middle ear and the vestibule of the inner ear. f. rotunda (f. cochleae ) the opening between the scala tympani of the cochlea and the middle ear.

Back  -    New Search

fenestration (fen-i-stray-shn) n.

a surgical operation in which a new opening is formed in the bony labyrinth of the inner ear as part of the treatment of deafness due to otosclerosis. It is now rarely performed, having been superseded by stapedectomy.

Back  -    New Search

fenoprofen (fen-oh-proh-fn) n.

an analgesic drug that also reduces inflammation (see NSAID) and is administered by mouth to treat arthritic conditions. Trade names: Fenopron , Progesic .

Back  -    New Search

fermentation (fer-men-tay-shn) n.

the biochemical process by which organic substances, particularly carbohydrates, are decomposed by the action of enzymes to provide chemical energy, as in the production of alcohol.

Back  -    New Search

ferning (fern-ing) n.

a test to determine if the amniotic membrane surrounding the fetus has ruptured in late pregnancy. A typical pattern of amniotic fluid crystallization occurs when the amniotic fluid dries.

Back  -    New Search

ferri- (ferro-) prefix

denoting iron.

Back  -    New Search

ferrous sulphate (fe-rs) n.

an iron salt administered by mouth to treat or prevent iron-deficiency anaemia. Similar preparations used to treat anaemia include ferrous fumarate and ferrous succinate .

Back  -    New Search

fertility rate (fer-til-iti) n.

the number of live births occurring in a year per 1000 women of child-bearing age (usually 15 to 44 years of age).

Back  -    New Search

fertilization (fer-ti-ly-zay-shn) n.

the fusion of a spermatozoon and an ovum to form a zygote.

Back  -    New Search

FESS n.

see FUNCTIONAL ENDOSCOPIC SINUS SURGERY.

Back  -    New Search

fester (fes-ter) vb.

(of superficial wounds) to become inflamed, with the formation of pus.

Back  -    New Search

festination (fes-ti-nay-shn) n.

the short tottering steps that characterize the gait of a patient with parkinsonism.

Back  -    New Search

fetal alcohol syndrome (FAS) (fee-t'l) n.

head and facial abnormalities and possibly mental retardation in a fetus due to intrauterine growth retardation caused by maternal over-consumption of alcohol during pregnancy.

Back  -    New Search

feticide (fee-ti-syd) n.

the destruction of a fetus in the uterus; for example by injection of a lethal substance into the fetal heart to achieve a late-stage termination of pregnancy.

Back  -    New Search

fetishism (fet-i-shizm) n.

sexual attraction to an inappropriate object (known as a fetish ). This may be a part of the body, clothing, or other objects (e.g. leather handbags or rubber sheets). Treatment can involve psychotherapy or behaviour therapy. See also SEXUAL DEVIATION.

Back  -    New Search

feto- prefix

denoting a fetus.

Back  -    New Search

fetor (foetor) (fee-ter) n.

an unpleasant smell. f. oris bad breath (see HALITOSIS).

Back  -    New Search

fetoscopy (fi-tos-kpi) n.

inspection of the fetus before birth by passing a special fibreoptic instrument (a fetoscope ) through the abdomen of a pregnant woman into her uterus. Usually performed in the 18th–20th week of gestation, it allows the inspection of the fetus for visible abnormalities and blood sampling by inserting a hollow needle under direct vision into a placental blood vessel. See PRENATAL DIAGNOSIS.

Back  -    New Search

fetus (foetus) (fee-ts) n.

a mammalian embryo during the later stages of development within the uterus; in humans it is an unborn child from its eighth week of development. f. papyraceous a twin fetus that has died in the uterus and become flattened and mummified.
—fetal adj.

Back  -    New Search

FEV n.

see FORCED EXPIRATORY VOLUME.

Back  -    New Search

fever (pyrexia) (fee-ver) n.

a rise in body temperature above the normal, i.e. above an oral temperature of 98.6°F (37°C) or a rectal temperature of 99°F (37.2°C), usually caused by bacterial or viral infection. Fever is generally accompanied by shivering, headache, nausea, constipation, or diarrhoea. intermittent f. a periodic rise and fall in body temperature, as in malaria. remittent f. a fever in which body temperature fluctuates but does not return to normal. See also RELAPSING FEVER.

Back  -    New Search

FHSA n.

see FAMILY HEALTH SERVICES AUTHORITY.

Back  -    New Search

fibr- (fibro-) prefix

denoting fibres or fibrous tissue.

Back  -    New Search

fibre (fy-ber) n.

1 (in anatomy) a thread-like structure, such as a muscle cell, a nerve fibre, or a collagen fibre.

2 (in dietetics) see DIETARY FIBRE.
Top

—fibrous(fy-brs) adj.

Back  -    New Search

fibre optics n.

the use of fibres for the transmission of light images. Synthetic fibres with special optical properties can be used in instruments to relay pictures of the inside of the body for direct observation or photography. See FIBRESCOPE.
—fibreoptic adj.

Back  -    New Search

fibrescope (fy-ber-skohp) n.

an endoscope that uses fibre optics for the transmission of images from the interior of the body. Being flexible, fibrescopes can be introduced into relatively inaccessible cavities of the body.

Back  -    New Search

fibril (fy-bril) n.

a very small fibre or a constituent thread of a fibre.
—fibrillar, fibrillary adj.

Back  -    New Search

fibrillation (fy-bril-ay-shn) n.

a rapid and chaotic beating of the many individual muscle fibres of the heart, which is consequently unable to maintain effective synchronous contraction. The affected part of the heart then ceases to pump blood. atrial f. a common type of arrhythmia that results in rapid and irregular heart and pulse rates. The main causes are atherosclerosis, chronic rheumatic heart disease, and hypertensive heart disease. ventricular f. fibrillation that causes the heart to stop beating (see CARDIAC ARREST). It is most commonly the result of myocardial infarction.

Back  -    New Search

fibrin (fib-rin) n.

the final product of the process of blood coagulation, produced by the action of the enzyme thrombin on a soluble precursor fibrinogen. Fibrin molecules link together to give a fibrous meshwork that forms the basis of a blood clot.

Back  -    New Search

fibrinogen (fi-brin--jn) n.

a substance (see COAGULATION FACTORS), present in blood plasma, that is acted upon by the enzyme thrombin to produce the insoluble protein fibrin in the final stage of blood coagulation.

Back  -    New Search

fibrinogenopenia (fi-brin--jen-oh-pee-ni) n.

see HYPOFIBRINOGENAEMIA.

Back  -    New Search

fibrinolysin (fib-ri-nol-i-sin) n.

see PLASMIN.

Back  -    New Search

fibrinolysis (fib-ri-nol-i-sis) n.

the process by which blood clots are removed from the circulation, involving digestion of the insoluble protein fibrin by the enzyme plasmin.

Back  -    New Search

fibrinolytic (fib-rin--lit-ik) adj.

describing a group of drugs that are capable of breaking down the protein fibrin, which is the main constituent of blood clots, and are therefore used to disperse blood clots (thrombi) that have formed within the circulation. They include streptokinase, alteplase, anistreplase, and urokinase.

Back  -    New Search

fibroadenoma (fy-broh-ad-in-oh-ma) n.

see ADENOMA.

Back  -    New Search

fibroblast (fy-broh-blast) n.

a widely distributed cell in connective tissue that is responsible for the production of both the ground substance and the precursors of collagen, elastic fibres, and reticular fibres.

Back  -    New Search

fibrocartilage (fy-broh-kar-ti-lij) n.

a tough kind of cartilage in which there are dense bundles of fibres in the matrix.

Back  -    New Search

fibrochondritis (fy-broh-kon-dry-tis) n.

an inflammation of fibrocartilage.

Back  -    New Search

fibrocyst (fy-broh-sist) n.

a benign tumour of fibrous connective tissue containing cystic spaces.
—fibrocystic (fy-broh-sis-tik) adj.

Back  -    New Search

fibrocystic disease of the pancreas n.

see CYSTIC FIBROSIS.

Back  -    New Search

fibrocyte (fy-broh-syt) n.

an inactive cell present in fully differentiated connective tissue. It is derived from a fibroblast.

Back  -    New Search

fibroelastosis (fy-broh-ee-las-toh-sis) n.

overgrowth or disturbed growth of the yellow (elastic) fibres in connective tissue. endocardial f. overgrowth and thickening of the wall of the heart's left ventricle.

Back  -    New Search

fibroid (fy-broid)

1 n. (fibromyoma , uterine fibroid ) a benign tumour of fibrous and muscular tissue, one or more of which may develop in the muscular wall of the uterus. Fibroids often cause pain and excessive menstrual bleeding; in some cases they can be removed surgically.

2 adj. resembling or containing fibres.
Top

Back  -    New Search

fibroma (fy-broh-m) n. (pl. fibromas or fibromata)

a nonmalignant tumour of connective tissue.

Back  -    New Search

fibromyoma (fy-broh-my-oh-m) n.

see FIBROID.

Back  -    New Search

fibroplasia (fy-broh-play-zi) n.

the production of fibrous tissue, occurring normally during the healing of wounds. See also RETROLENTAL FIBROPLASIA.

Back  -    New Search

fibrosarcoma (fy-broh-sar-koh-m) n.

a malignant tumour of connective tissue, derived from fibroblasts. Fibrosarcomas may arise in soft tissue or bone; they can affect any organ but are most common in the limbs, particularly the leg.

Back  -    New Search

fibrosis (fy-broh-sis) n.

thickening and scarring of connective tissue, most often a consequence of inflammation or injury. pulmonary interstitial f. thickening and stiffening of the lining of the alveoli causing progressive breathlessness. See also CYSTIC FIBROSIS, RETROPERITONEAL FIBROSIS.

Back  -    New Search

fibrositis (fy-br-sy-tis) n.

inflammation of fibrous connective tissue, especially an acute inflammation of back muscles and their sheaths, causing pain and stiffness.

Back  -    New Search

fibula (fib-yoo-l) n.

the long thin outer bone of the lower leg. The head of the fibula articulates with the tibia just below the knee; the lower end projects laterally and articulates with one side of the talus.

Back  -    New Search

field (feeld) n.

(in radiotherapy) an area of the body selected for treatment with radiotherapy. Radiation is administered to the field by focusing the beam of particles emitted by the radiotherapy machine and shielding the surrounding area of the body. mantle f. the neck, armpits, and central chest.

Back  -    New Search

field of vision n.

see VISUAL FIELD.

Back  -    New Search

FIGO staging n.

a classification drawn up by the International Federation of Gynaecology and Obstetrics to define the extent of spread of cancers of the ovary, uterus, and cervix.

Back  -    New Search

filament (fil--mnt) n.

a very fine threadlike structure, such as a chain of bacterial cells.
—filamentous (fil--ment-s) adj.

Back  -    New Search

filaria (fil-air-i) n. (pl. filariae)

any of the long threadlike nematode worms that, as adults, are parasites of the connective and lymphatic tissues of man capable of causing disease. They include the genera Brugia, Loa, Onchocerca, and Wuchereria. See also MICROFILARIA.
—filarial adj.

Back  -    New Search

filariasis (fil-er-l--sis) n.

a disease, common in the tropics and subtropics, caused by the presence in the lymph vessels of the filariae Wuchereria bancrofti and Brugia malayi. The lymph vessels eventually become blocked, causing the surrounding tissues to swell (see ELEPHANTIASIS). Filariasis is treated with the drug diethylcarbamazine.

Back  -    New Search

filiform (fil-i-form) adj.

shaped like a thread. f. papillae threadlike papillae on the tongue.

Back  -    New Search

filipuncture (fil-i-punk-cher) n.

the insertion of a fine wire thread into an aneurysm in order to cause clotting of the blood within it.

Back  -    New Search

filling (fil-ing) n.

(in dentistry) the operation of inserting a specially prepared substance into a cavity drilled in a tooth, often in the treatment of dental caries.

Back  -    New Search

filtration (fil-tray-shn) n.

the passage of a liquid through a porous filter in order to separate the solids or suspended particles within it.

Back  -    New Search

filum (fy-lm) n.

a threadlike structure. f. terminale the slender tapering terminal section of the spinal cord.

Back  -    New Search

fimbria (fim-bri) n. (pl. fimbriae)

a fringe or fringelike process, such as any of the finger-like projections that surround the opening of the ovarian end of the Fallopian tube.
—fimbrial (fim-bri-l) adj.

Back  -    New Search

fimbrial cyst n.

a simple cyst of the fimbria of the Fallopian tube.

Back  -    New Search

finasteride (fin-ass-t-ryd) n.

a drug that causes shrinkage of the prostate gland and is administered by mouth to relieve the symptoms caused by an enlarged gland obstructing the outflow of urine from the bladder. Trade name: Proscar .

Back  -    New Search

fingerprint (fing-er-print) n.

the distinctive pattern of minute ridges in the outer horny layer of the skin. Every individual has a unique pattern of loops, whorls, or arches. See also DERMATOGLYPHICS.

Back  -    New Search

first aid (ferst) n.

procedures used in an emergency to help a wounded or ill patient before the arrival of a doctor or admission to hospital.

Back  -    New Search

first intention n.

see INTENTION.

Back  -    New Search

first-level nurse n.

a person who has completed a programme of nursing education that includes the study of life and nursing sciences, clinical experience for effective practice and direction of nursing care, and preparation for a leadership role. A first-level nurse is responsible for planning, providing, and evaluating nursing care in all settings for the promotion of health, prevention of illness, and care and rehabilitation of the sick. See NURSE.

Back  -    New Search

fission (fish-n) n.

a method of asexual reproduction in which the body of a protozoan or bacterium splits into two equal parts (binary f. ), as in the amoebae, or more than two equal parts (multiple f. ).

Back  -    New Search

fissure (fish-er) n.

1 (in anatomy) a groove or cleft.

2 (in pathology) a cleftlike defect in the skin or mucous membrane caused by some disease process. anal f. a break in the skin lining the anal canal, usually as a consequence of constipation, causing pain during bowel movements and sometimes bleeding.
Top

3 (in dentistry) a naturally occurring groove in the enamel on the surface of a tooth, especially a molar. It is a common site of dental caries.
Top

Back  -    New Search

fistula (fiss-tew-l) n. (pl. fistulae)

an abnormal communication between two hollow organs or between a hollow organ and the exterior. Many fistulae are caused by infection or injury, but there are a number of other causes. anal f. an opening between the anal canal and the surface of the skin that may develop after an abscess in the rectum has burst (see ISCHIORECTAL ABSCESS). biliary f. a fistula that may develop as a complication of gall bladder surgery. gastrocolic f. a fistula between the colon and the stomach that may result from malignant growth or ulceration. rectovaginal f. an opening between the rectum and vagina that occurs as a congenital abnormality. vesicovaginal f. an opening between the bladder and the vagina causing urinary incontinence. It may result from damage during surgery, radiation damage following radiotherapy for pelvic malignancy, or prolonged obstructed labour.

Back  -    New Search

fit (fit) n.

a sudden attack. The term is commonly used specifically for the seizures of epilepsy but it is also used more generally, e.g. a fit of coughing.

Back  -    New Search

fixation (fiks-ay-shn) n.

1 (in psychoanalysis) a failure of psychological development, in which traumatic events prevent a child from progressing to the next developmental stage. See also PSYCHOSEXUAL DEVELOPMENT.

2 a procedure for the hardening and preservation of tissues or microorganisms to be examined under a microscope.
Top

Back  -    New Search

fixator (fiks-ay-ter) n.

an apparatus used to immobilize a fracture. external f. a rigid frame that connects pins passed through the skin into the bone above and below a fracture. It is used particularly to treat some compound fractures and also, for limb lengthening.

Back  -    New Search

FK506 n.

see TACROLIMUS.

Back  -    New Search

flaccid (flak-sid) adj.

1 flabby and lacking in firmness.

2 characterized by a decrease in muscle tone (e.g. f. paralysis ).
Top

—flaccidity (flak-sid-iti) n.

Back  -    New Search

flagellate (flaj-l-ayt) n.

a type of protozoan with one or more flagella projecting from its body surface, by means of which it is able to swim. Some flagellates are parasites of man. See TRYPANOSOMIASIS, LEISHMANIA, GIARDIASIS, TRICHOMONAS.

Back  -    New Search

flagellum (fl-jel-m) n. (pl. flagella)

a fine long whiplike thread attached to certain types of cell (e.g. spermatozoa and flagellates). Flagella are responsible for the movement of the organisms to which they are attached.

Back  -    New Search

flail chest (flayl) n.

instability of the chest wall due to multiple fractures of the ribs, causing paradoxical breathing.

Back  -    New Search

flap (flap) n.

(in surgery) a strip of tissue dissected away from the underlying structures but left attached at one end so that it retains its blood and nerve supply in a pedicle. The flap is then used to repair a defect in another part of the body or to cover the end of a bone in an amputated limb. It is detached from its original site when it has healed into the new one.

Back  -    New Search

flare (flair) n.

1 reddening of the skin that spreads outwards from a focus of infection or irritation in the skin.

2 the red area surrounding an urticarial weal.
Top

Back  -    New Search

flashback (flash-bak) n.

vivid involuntary reliving of the perceptual abnormalities experienced during a previous episode of drug intoxication, including hallucinations and derealization.

Back  -    New Search

flat-foot (flat-fuut) n.

absence of the arching of the foot, so that the sole lies flat upon the ground. It may be present in infancy or be acquired in adult life. Medical name: pes planus .

Back  -    New Search

flatulence (flat-yoo-lns) n.

1 the expulsion of gas or air from the stomach through the mouth; belching.

2 a sensation of abdominal distension.
Top

—flatulent adj.

Back  -    New Search

flatus (flay-ts) n.

intestinal gas, composed partly of swallowed air and partly of gas produced by bacterial fermentation of intestinal contents.

Back  -    New Search

flatworm (platyhelminth) (flat-werm) n.

any of the flat-bodied worms, including the flukes and tapeworms. Both these groups contain many parasites of medical importance.

Back  -    New Search

flav- (flavo-) prefix

denoting yellow.

Back  -    New Search

flea (flee) n.

a small wingless bloodsucking insect with a laterally compressed body and long legs adapted for jumping. Adult fleas are temporary parasites on birds and mammals and those species that attack man (Pulex, Xenopsylla, and Nosopsyllus) may be important in the transmission of various diseases. Their bites may become a focus of infection.

Back  -    New Search

flecainide (flek-ay-nyd) n.

a drug used to control irregular heart rhythms. It is administered by mouth. Trade name: Tambocor .

Back  -    New Search

flexibilitas cerea (fleks-i-bil-i-tas seer-i) n.

a feature of catatonic patients in which the limbs may be moved passively by another person into positions that are then retained for hours on end. See CATATONIA.

Back  -    New Search

flexion (flek-shn) n.

the bending of a joint so that the bones forming it are brought towards each other. plantar f. the bending of the toes (or fingers) downwards, towards the sole (or palm). See also DORSIFLEXION.

Back  -    New Search

Flexner's bacillus (fleks-nerz) n.

the bacterium Shigella flexneri, which causes a form of bacillary dysentery. [S. Flexner (1863–1946), US pathologist]

Back  -    New Search

flexor (fleks-er) n.

any muscle that causes bending of a limb or other part.

Back  -    New Search

flexure (flek-sher) n.

a bend in an organ or part, such as the hepatic and splenic flexures of the colon.

Back  -    New Search

floaters (floh-terz) pl. n.

opacities in the vitreous humour of the eye, which cast a shadow on the retina and are therefore seen as dark shapes against a bright background in good illumination.

Back  -    New Search

floccillation (flok-si-lay-shn) n.

see CARPHOLOGY.

Back  -    New Search

flocculation (flok-yoo-lay-shn) n.

a reaction in which normally invisible material leaves solution to form a coarse suspension or precipitate. See also AGGLUTINATION.

Back  -    New Search

flooding (flud-ing) n.

1 excessive bleeding from the uterus, as in menorrhagia or miscarriage.

2 (in psychology) (also called implosion ) a method of treating phobias in which the patient is exposed intensively and at length to the feared object, either in reality or fantasy.
Top

Back  -    New Search

floppy baby syndrome (flop-i) n.

see AMYOTONIA CONGENITA.

Back  -    New Search

flowmeter (floh-mee-ter) n.

an instrument for measuring the flow of a liquid or gas. laser Doppler f. an instrument for measuring blood flow through tissue (e.g. skin) utilizing a laser beam.

Back  -    New Search

flucloxacillin (floo-kloks--sil-in) n.

a semisynthetic penicillin, readily absorbed when taken by mouth, which is effective against bacteria that produce penicillinase. Trade names: Floxapen , Magnapen .

Back  -    New Search

fluconazole (floo-kon--zohl) n.

an anti-fungal drug used to treat candidosis in any part of the body, externally or internally. It is administered by mouth. Trade name: Diflucan .

Back  -    New Search

fluctuation (fluk-tew-ay-shn) n.

the characteristic feeling of a wave motion produced in a fluid-filled part of the body by an examiner's fingers. If fluctuation is present when a swelling is examined, this is an indication that there is fluid within.

Back  -    New Search

flucytosine (floo-sy-toh-seen) n.

an anti-fungal drug that is effective against systemic infections, including cryptococcosis and candidosis. It can be administered by mouth.

Back  -    New Search

fludrocortisone (floo-droh-kor-tiz-ohn) n.

a synthetic corticosteroid administered by mouth to treat disorders of the adrenal glands. Trade name: Florinef .

Back  -    New Search

fluke (flook) n.

any of the parasitic flatworms that belong to the group Trematoda. Adult flukes are parasites of man, occurring in the liver (see FASCIOLA), lungs (see PARAGONIMIASIS), gut (see HETEROPHYIASIS), and blood vessels (see SCHISTOSOMA) and often cause serious disease.

Back  -    New Search

flumazenil (floo-maz-i-nil) n.

a benzodiazepine antagonist drug, used in anaesthesia to reverse the effects of benzodiazepines on the nervous system. It is administered by injection. Trade name: Anexate .

Back  -    New Search

flunisolide (floo-nis-oh-lyd) n.

an antiinflammatory corticosteroid drug used in the long-term treatment of bronchial asthma and rhinitis. It is administered as an inhalation or a spray. Trade name: Syntaris .

Back  -    New Search

flunitrazepam (floo-ni-traz--pam) n.

a benzodiazepine drug used for the short-term treatment of insomnia. It is administered by mouth. Trade name: Rohypnol .

Back  -    New Search

fluocinonide (floo--sin-oh-nyd) n.

a synthetic corticosteroid used topically to reduce inflammation. It is applied to the skin as a cream, gel, ointment, or solution. Trade name: Metosyn .

Back  -    New Search

fluorescein sodium (floo-er-ess-i-in) n.

a water-soluble orange dye that glows with a brilliant green colour when blue light is shone on it. A dilute solution is used to detect defects in the surface of the cornea, since it stains areas where the epithelium is not intact. See ANGIOGRAPHY.

Back  -    New Search

fluorescence (floo-er-ess-ns) n.

the emission of light by a material as it absorbs radiation from outside. The radiation absorbed may be visible or invisible (e.g. ultraviolet rays or X-rays). See FLUOROSCOPE.
—fluorescent adj.

Back  -    New Search

fluoridation (floo-er-id-ay-shn) n.

the addition of fluoride to drinking water in order to reduce dental caries. Drinking water with a fluoride ion content of one part per million is effective in reducing caries throughout life when given during the years of tooth development. See also FLUOROSIS.

Back  -    New Search

fluoride (floo-eryd) n.

a compound of fluorine. The incorporation of fluoride ions in the enamel of teeth makes them more resistant to dental caries. Fluoride may be applied through fluoridation or topically in toothpaste or by a dentist.

Back  -    New Search

fluoroscope (floo-er--skohp) n.

an instrument on which X-ray images may be viewed directly, without taking and developing X-ray photographs. It consists basically of a fluorescent screen , which is coated with chemicals that exhibit fluorescence when exposed to X-rays. Fluoroscopes are used for mass chest X-ray examinations.

Back  -    New Search

fluorosis (floo-er-oh-sis) n.

the effects of high fluoride intake. When the level of fluoride in the water supply is above 2 parts per million the enamel of teeth becomes mottled. At above 8 parts per million, calcification of ligaments occurs. See also FLUORIDATION.

Back  -    New Search

fluorouracil (floo-er-oh-yoor--sil) n.

a drug that prevents cell growth (see ANTIMETABOLITE) and is used in the treatment of cancers of the digestive system and breast. It is administered by mouth or injection. Fluorouracil is also applied as a cream to treat certain skin conditions, including skin cancer.

Back  -    New Search

fluoxetine (floo-oks-i-teen) n.

an antidepressant drug that acts by prolonging the action of the neurotransmitter serotonin (5-hydroxytryptamine) in the brain (see SSRI). It is administered by mouth. Trade name: Prozac .

Back  -    New Search

flupenthixol (floo-pen-thiks-ol) n.

an antipsychotic drug used to treat schizophrenia and other psychoses. It is administered by mouth and by injection. Trade names: Depixol , Fluanxol .

Back  -    New Search

fluphenazine (floo-fen--zeen) n.

a phenothiazine antipsychotic drug used for the treatment of schizophrenia and other psychotic disorders. It is administered by mouth or injection. Trade names: Modecate , Moditen .

Back  -    New Search

flurazepam (floor-az--pam) n.

a benzodiazepine drug administered by mouth to treat insomnia and sleep disturbances (see HYPNOTIC). Trade name: Dalmane .

Back  -    New Search

flurbiprofen (fler-bip-roh-fen) n.

an analgesic that relieves inflammation (see NSAID), used in the treatment of rheumatoid arthritis and osteoarthritis and to prevent contraction of the pupil during eye surgery. Trade names: Froben , Ocufen .

Back  -    New Search

fluspirilene (floo-spy-ri-leen) n.

an antipsychotic drug administered by injection to treat schizophrenia. Trade name: Redeptin .

Back  -    New Search

flutter (flut-er) n.

a disturbance of normal heart rhythm, less rapid and less chaotic than fibrillation.

Back  -    New Search

fluvoxamine (floo-voks--meen) n.

an antidepressant drug that acts by prolonging the action of the neurotransmitter serotonin (5-hydroxytryptamine) in the brain (see SSRI). It is taken by mouth. Trade name: Faverin .

Back  -    New Search

flux (fluks) n.

an abnormally copious flow from an organ or cavity.

Back  -    New Search

fly (fly) n.

a two-winged insect belonging to the order Diptera. The mouthparts of flies are adapted for sucking and sometimes also for piercing and biting. Fly larvae (maggots) may infest human tissues and cause disease (see MYIASIS).

Back  -    New Search

focal distance (foh-kl) n.

(of the eye) the distance between the lens and the point behind the lens at which light from a distant object is focused.

Back  -    New Search

focus (foh-ks)

1 n. the point at which rays of light converge after passing through a lens.

2 n. the principal site of an infection or other disease.
Top

3 vb. (in ophthalmology) to accommodate (see ACCOMMODATION).
Top

Back  -    New Search

foetus (fee-ts) n.

see FETUS.

Back  -    New Search

folic acid (pteroylglutamic acid) (foh-lik) n.

a B vitamin that is important in the synthesis of nucleic acids. The metabolic role of folic acid is interdependent with that of vitamin B_12 (both are required by rapidly dividing cells) and a deficiency of one may lead to deficiency of the other. A deficiency of folic acid results in the condition of megaloblastic anaemia. Good sources of folic acid are liver, yeast extract, and green leafy vegetables; increased intake shortly before conception and during the first three months of pregnancy helps prevent spina bifida and other congenital malformations in the fetus.

Back  -    New Search

folie à deux (communicated insanity) (fol-i a der) n.

a condition in which two people who are closely involved with each other share a system of delusions.

Back  -    New Search

folinic acid (foh-lin-ik) n.

a derivative of folic acid involved in purine synthesis. Administered by mouth or by injection, it is used to reverse the biological effects of methotrexate and so prevent excessive toxicity (f. a. rescue ). Trade name: Leucovorin .

Back  -    New Search

follicle (fol-ikl) n.

a small secretory cavity, sac, or gland. See also GRAAFIAN FOLLICLE, HAIR (FOLLICLE).
—follicular (f-lik-yoo-ler) adj.

Back  -    New Search

follicle-stimulating hormone (FSH) n.

a hormone (see GONADOTROPHIN) synthesized and released by the anterior pituitary gland. FSH stimulates ripening of the follicles in the ovary and formation of sperm in the testes. It is administered by injection to treat sterility.

Back  -    New Search

folliculitis (f-lik-yoo-ly-tis) n.

inflammation of hair follicles in the skin, commonly caused by infection. See also SYCOSIS.

Back  -    New Search

fomentation (foh-men-tay-shn) n.

see POULTICE.

Back  -    New Search

fomes (foh-meez) n. (pl. fomites)

any object that is used or handled by a person with a communicable disease and may therefore become contaminated with the infective organisms and transmit the disease to a subsequent user. Common fomites are towels, bed-clothes, cups, and money.

Back  -    New Search

fontanelle (fon-t-nel) n.

an opening in the skull of a fetus or young infant due to incomplete ossification of the cranial bones and the resulting incomplete closure of the sutures. anterior f. the opening at the junction of the coronal, frontal, and sagittal sutures. posterior f. the opening at the junction of the sagittal and lambdoidal sutures.

Back  -    New Search

food poisoning (food) n.

an illness affecting the digestive system that results from eating food contaminated either by bacteria or bacterial toxins or, less commonly, by poisonous chemicals such as lead or mercury. It can also be caused by eating poisonous fungi, berries, etc. Symptoms include vomiting, diarrhoea, abdominal pain, and nausea. Food-borne infections are caused by bacteria of the genus Salmonella, Campylobacter, and Listeria in foods of animal origin. Toxinproducing bacteria causing food poisoning include those of the genus Staphylococcus, which rapidly multiply in warm foods; pathogenic Escherichia coli; and the species Clostridium perfringens, which multiplies in reheated cooked meals. See also BOTULISM, GASTROENTERITIS.

Back  -    New Search

foot (fuut) n.

the terminal organ of the lower limb. It comprises the seven bones of the tarsus, the five metatarsal bones, and the phalangeal bones plus the surrounding tissues.

Back  -    New Search

foot drop (fuut-drop) n.

inability to keep the foot at right angles to the leg, caused by paralysis of the anterior leg muscles, pressure of bedclothes, or insufficient support for the sole of the foot when the leg is splinted.

Back  -    New Search

foramen (fo-ray-men) n. (pl. foramina)

an opening or hole, particularly in a bone. apical f. the small opening at the apex of a tooth. f. magnum a large hole in the occipital bone through which the spinal cord passes. f. ovale the opening between the two atria of the fetal heart, which allows blood to flow from the right to the left side of the heart by displacing a membranous valve.

Back  -    New Search

forced expiratory volume (FEV) (forst iks-pir--ter-i vol-yoom) n.

the volume of air exhaled in a given period (usually limited to 1 second in tests of vital capacity). FEV is reduced in patients with obstructive airways disease and diminished lung volume.

Back  -    New Search

forceps (for-seps) n.

a pincer-like instrument designed to grasp an object so that it can be held firm or pulled. Specially designed forceps are used by surgeons and dentists in operations (see illustration).

Back  -    New Search

forebrain (for-brayn) n.

the furthest forward division of the brain, consisting of the diencephalon and the two cerebral hemispheres.

Back  -    New Search

foregut (for-gut) n.

the front part of the embryonic gut, which gives rise to the oesophagus, stomach, and part of the small intestine.

Back  -    New Search

forensic medicine (fer-en-sik) n.

the branch of medicine concerned with the scientific investigation of the causes of injury and death in unexplained circumstances, particularly when criminal activity is suspected.

Back  -    New Search

forequarter amputation (for-kwor-ter) n.

an operation involving removal of an entire arm, including the scapula and clavicle. It is usually performed for soft tissue or bone sarcomas arising from the upper arm or shoulder. Compare HINDQUARTER AMPUTATION.

Back  -    New Search

foreskin (for-skin) n.

see PREPUCE.

Back  -    New Search

forewaters (for-waw-terz) n.

the amniotic fluid that escapes from the uterus through the vagina when that part of the amnion lying in front of the presenting part of the fetus ruptures, either spontaneously or by amniotomy. Spontaneous rupture is usual in labour but rupture may occur before labour starts (premature rupture of membranes).

Back  -    New Search

formaldehyde (for-mal-di-hyd) n.

the aldehyde derivative of formic acid, formerly used as a vapour to sterilize and disinfect rooms and such items as mattresses and blankets. The toxic vapour is produced by boiling formalin in an open container or using it in a sealed autoclave.

Back  -    New Search

formalin (for-m-lin) n.

a solution containing 40% formaldehyde in water, used as a sterilizing agent and, in pathology, as a fixative.

Back  -    New Search

formication (for-mi-kay-shn) n.

a prickling sensation said to resemble the feeling of ants crawling over the skin. It is sometimes a symptom of drug intoxication and can also be reported by patients with Parkinson's disease.

Back  -    New Search

formula (form-yoo-l) n.

1 a representation of the structure of a chemical compound using symbols and subscript numbers for the atoms it contains (e.g. H_2O for water; CO_2 for carbon dioxide).

2 a prescription for a drug.
Top

Back  -    New Search

formulary (form-yoo-ler-i) n.

a compendium of formulae used in the preparation of medicinal drugs.

Back  -    New Search

fornix (for-niks) n. (pl. fornices)

an arched or vaultlike structure. f. cerebri a triangular structure of white matter in the brain, situated between the hippocampus and hypothalamus. f. of the vagina any of three vaulted spaces at the top of the vagina, around the cervix of the uterus.

Back  -    New Search

Forrest screening (fo-rist) n.

a national breast screening programme, introduced in 1988, in which regular mammography is available for all women between the ages of 50 and 64. It enables the early diagnosis of breast cancer in order to improve treatment and reduce mortality. [Sir P. Forrest (1923– ), Scottish surgeon]

Back  -    New Search

foscarnet (fos-kar-net) n.

an antiviral drug used to treat infections caused by herpesviruses, including cytomegalo-viruses, that are resistant to acyclovir, especially in patients with AIDS. It is administered by intravenous injection.

Back  -    New Search

fossa (fos-) n. (pl. fossae)

a depression or hollow. cubital f. the triangular hollow at the front of the elbow joint. iliac f. the depression in the inner surface of the ilium. pituitary f. the hollow in the sphenoid bone in which the pituitary gland is situated. tooth f. a pit in the enamel on the surface of a tooth.

Back  -    New Search

Fothergill's operation

see DONALD-FOTHERGILL OPERATION.

Back  -    New Search

fourchette (foor-shet) n.

a thin fold of skin at the back of the vulva.

Back  -    New Search

fovea (foh-vi) n.

(in anatomy) a small depression, especially the shallow pit in the retina at the back of the eye. It contains a large number of cones and is therefore the area of greatest acuity of vision. See also MACULA (LUTEA).

Back  -    New Search

fracture (frak-cher) n.

breakage of a bone, either complete or incomplete. Treatment includes realignment of the bone ends and immobilization by external splints or internal fixation. cervical f. a fracture of a vertebra in the neck, with effects ranging from minor, requiring no treatment, to paralysis and instant death. Colles' f. a fracture of the lower end of the radius and the tip of the ulna just above the wrist. The hand and wrist below the fracture are displaced backwards. comminuted f. a fracture in which the bone is broken into more than two pieces. compound (or open ) f. a fracture in which the bone end pierces the overlying skin. greenstick f. an incomplete break in a bone occurring in children. impacted f. a fracture in which the bone ends are driven into each other. march f. a fracture through the neck of the second or third metatarsal bone, associated with excess walking. pathological f. fracture of a diseased or abnormal bone, usually resulting from a force insufficient to fracture a normal bone. Pott's f. a fracture of the lower end of the fibula accompanied by a fracture of the malleolus of the tibia. simple f. a clean break with little damage to surrounding tissues. Smith's f. a fracture just above the wrist, across the lower end of the radius. The hand and wrist below the fracture are displaced forwards. See illustration.

Back  -    New Search

fraenectomy (free-nek-tmi) n.

see FRENECTOMY.

Back  -    New Search

fraenum (free-nm) n.

see FRENUM.

Back  -    New Search

fragile-X syndrome (fraj-yl-eks) n.

a major genetic disorder caused by an abnormality in an X chromosome. The fragile-X syndrome is second only to Down's syndrome as a cause of mental retardation. It predominantly affects males, but about one-third of the females with this mutation on one of their two X chromosomes are also mentally retarded.

Back  -    New Search

fragilitas (fr-jil-i-tas) n.

abnormal brittleness or fragility. f. crinium brittleness of the hair. f. ossium brittleness of the bones (see OSTEOGENESIS (IMPERFECTA)).

Back  -    New Search

framboesia (fram-bee-zi) n.

see YAWS.

Back  -    New Search

framycetin (fra-my-see-tin) n.

an antibiotic used mainly in the form of an ointment, cream, or eye or ear drops to treat skin, eye, and ear infections. Trade names: Sofradex , Soframycin .

Back  -    New Search

fraternal twins (fr-ter-nl) pl. n.

see TWINS.

Back  -    New Search

freckle (frek-l) n.

a small harmless brown spot on the skin, commonly seen on the face and arms of fair-skinned people, due to excessive production of melanin without an increase in melanocytes after exposure to sunlight. Compare LENTIGO.

Back  -    New Search

free association (free) n.

(in psychoanalysis) a technique in which the patient is encouraged to pursue a particular train of ideas as they enter his or her consciousness. See also ASSOCIATION OF IDEAS.

Back  -    New Search

Freiburg's disease (fry-bergz) n.

osteochondritis affecting the head of the second metatarsal bone. [A. H. Freiburg (1868–1940), US orthopaedic surgeon]

Back  -    New Search

Frei test (fry) n.

a rarely used diagnostic test for the sexually transmitted disease lymphogranuloma venereum. [W. S. Frei (1885–1943), German dermatologist]

Back  -    New Search

fremitus (frem-i-ts) n.

vibrations or tremors in a part of the body, detected by palpation or auscultation. The term is most commonly applied to vibrations perceived through the chest when a patient breathes, speaks (vocal f. ), or coughs.

Back  -    New Search

frenectomy (fraenectomy) (free-nek-tomi) n.

an operation to remove the frenum, including the underlying fibrous tissue.

Back  -    New Search

frenulum (fren-yoo-lm) n.

see FRENUM.

Back  -    New Search

frenum (fraenum, frenulum) (free-nm) n.

1 any of the folds of mucous membrane under the tongue or between the gums and the upper or lower lips.

2 any of several other structures of similar appearance.
Top

Back  -    New Search

frequency (free-kwn-si) n.

(of urine) the frequent passage of urine, which usually indicates genitourinary disorders and diseases but also accompanies polyuria.

Back  -    New Search

Freudian (froi-di-n) adj.

relating to or describing the work and ideas of Sigmund Freud (1856–1939): applied particularly to the school of psychiatry based on his teachings (see PSYCHOANALYSIS).

Back  -    New Search

friar's balsam (fry-erz) n.

a tincture of benzoin, balsam of Tolu, storax, aloes, and various other plant extracts, the vapour of which is inhaled to relieve bronchitis.

Back  -    New Search

friction murmur (friction rub) (frik-shn) n.

a scratching sound, heard over the heart with the aid of the stethoscope, in patients who have pericarditis. It results from the two inflamed layers of the pericardium rubbing together during activity of the heart.

Back  -    New Search

Friedländer's bacillus (freed-len-derz) n.

a Gram-negative rodlike bacterium, Klebsiella pneumoniae, that causes a form of pneumonia. [K. Friedländer (1847–87), German pathologist]

Back  -    New Search

Friedreich's ataxia (freed-ryks) n.

see ATAXIA. [N. Friedreich (1825–82), German neurologist]

Back  -    New Search

frigidity (fri-jid-iti) n.

lack of sexual desire or inability to achieve orgasm, especially in a woman.

Back  -    New Search

fringe medicine (frinj) n.

see ALTERNATIVE MEDICINE.

Back  -    New Search

frog plaster (frog) n.

a plaster of Paris splint used to maintain the legs in their correct position after a congenital dislocation of the hip has been corrected by manipulation.

Back  -    New Search

Fröhlich's syndrome (frer-liks) n.

a disorder of the hypothalamus affecting males: the boy is overweight with sexual development absent and disturbances of sleep and appetite. Medical name: dystrophia adiposogenitalis . [A. Fröhlich (1871–1953), Austrian neurologist]

Back  -    New Search

Froin's syndrome (frwahnz) n.

a condition in which the cerebrospinal fluid (CSF) displays a combination of yellow colour and high protein content. It is characteristic of a block to the spinal circulation of CSF caused by a tumour. [G. Froin (1874–1932), French physician]

Back  -    New Search

frontal (frun-t'l) adj.

1 of or relating to the forehead. f. bone the bone forming the forehead and the upper parts of the orbits. f. sinuses see PARANASAL SINUSES.

2 denoting the anterior part of a body or organ. f. lobe the anterior part of each cerebral hemisphere, extending as far back as the deep central sulcus of its upper and outer surface.
Top

Back  -    New Search

frostbite (frost-byt) n.

damage to the tissues caused by freezing. The affected parts, usually the nose, fingers, or toes, become pale and numb. Ice forms in the tissues, which may thus be destroyed, and amputation may become necessary. Frostbitten skin is highly susceptible to bacterial infection.

Back  -    New Search

frozen shoulder (froh-zn) n.

chronic painful stiffness of the shoulder joint. This may follow injury, a stroke, or myocardial infarction or may gradually develop for no apparent reason. See also CAPSULITIS.

Back  -    New Search

frozen watchfulness n.

the state of a child who is unresponsive to its surroundings but is clearly aware of them. Frozen watchfulness is usually a marker of child abuse.

Back  -    New Search

fructose (fruk-tohz) n.

a simple sugar found in honey and in such fruit as figs. Fructose is one of the two sugars in sucrose.

Back  -    New Search

fructosuria (levulosuria) (fruk-tohz-yoor-i) n.

the presence of fructose (levulose) in the urine.

Back  -    New Search

frusemide (frus--myd) n.

a loop diuretic administered by mouth or injection to treat fluid retention (oedema) associated with heart, liver, or kidney disease and also high blood pressure. Trade name: Lasix .

Back  -    New Search

FSH n.

see FOLLICLE-STIMULATING HORMONE.

Back  -    New Search

FTT n.

see FAILURE TO THRIVE.

Back  -    New Search

Fuchs' endothelial dystrophy (fooks) n.

a hereditary condition in which the endothelium of the cornea fails to function with age; it results in thickening and swelling of the cornea and hence reduced vision. [E. Fuchs (1851–1913), German ophthalmologist]

Back  -    New Search

fuchsin (magenta) (fook-sin) n.

any one of a group of reddish to purplish dyes used in staining bacteria for microscopic observation and capable of killing various disease-causing microorganisms.

Back  -    New Search

-fuge suffix

denoting an agent that drives away, repels, or eliminates.

Back  -    New Search

fugue (fewg) n.

a period of memory loss during which the patient leaves his usual surroundings and wanders aimlessly or starts a new life elsewhere. It is often preceded by psychological conflict and depression (see DISSOCIATIVE DISORDER) or it may be associated with organic mental disease.

Back  -    New Search

fulguration (electrodesiccation) (ful-gewr-ay-shn) n.

the destruction with a diathermy instrument of warts, growths, or unwanted areas of tissue, particularly inside the bladder.

Back  -    New Search

fulminating (fulminant, fulgurant) (ful-min-ayt-ing) adj.

describing a condition or symptom that is of very sudden onset, severe, and of short duration.

Back  -    New Search

fumigation (few-mig-ay-shn) n.

the use of gases or vapours, such as formaldehyde or chlorine, to bring about disinfestation of clothing, buildings, etc.

Back  -    New Search

functional disorder (funk-shn-l) n.

a condition in which a patient complains of symptoms for which no physical cause can be found. Such a condition is frequently an indication of a psychiatric disorder. Compare ORGANIC (DISORDER).

Back  -    New Search

functional endoscopic sinus surgery (FESS) n.

surgery of the paranasal sinuses using endoscopes. Routes of sinus drainage and aeration that are blocked by disease are cleared and enlarged, allowing the rest of the sinuses to return to normal.

Back  -    New Search

functional independence measure n.

a table recommended by the WHO for assessing the degree of whole-person disability, being particularly useful for judging the extent of recovery from serious injury. It has five grades, ranging from 0 (fully independent) to 4 (completely dependent).

Back  -    New Search

Functional Recovery Index n.

an international index, published by the World Health Organization, that grades the degree of recovery after serious injury.

Back  -    New Search

fundoplication (fun-doh-pli-kay-shn) n.

a surgical operation for gastro-oesophageal reflux disease in which the upper part of the stomach is wrapped around the lower oesophagus.

Back  -    New Search

fundoscopy (ophthalmoscopy) (fund-os-kpi) n.

examination of the interior of the eye by means of an ophthalmoscope.

Back  -    New Search

fundus (fun-ds) n.

1 the base of a hollow organ: the part farthest from the opening.

2 the interior concavity forming the back of the eyeball, opposite the pupil.
Top

Back  -    New Search

fungicide (fun-ji-syd) n.

an agent that kills fungi. See also ANTIFUNGAL.

Back  -    New Search

fungoid (fung-oid)

1 adj. resembling a fungus.

2 n. a fungus-like growth.
Top

Back  -    New Search

fungus (fung-s) n. (pl. fungi)

a simple organism (formerly regarded as a plant) that lacks the green pigment chlorophyll. Fungi include the yeasts, rusts, moulds, and mushrooms. Some species infect and cause disease in man. Some yeasts are a good source of vitamin B and many antibiotics are obtained from the moulds (see PENICILLIN). See also YEAST.
—fungal adj.

Back  -    New Search

funiculitis (few-nik-yoo-ly-tis) n.

inflammation of the spermatic cord.

Back  -    New Search

funiculus (few-nik-yoo-ls) n.

1 any of the three main columns of white matter found in each lateral half of the spinal cord.

2 a bundle of nerve fibres enclosed in a sheath.
Top

3 (formerly) the spermatic cord or umbilical cord.
Top

Back  -    New Search

funis (few-nis) n.

(in anatomy) any cordlike structure, especially the umbilical cord.

Back  -    New Search

funnel chest (fun-l) n.

a developmental abnormality in which the sternum is depressed and the ribs and costal cartilages curve inwards. Medical name: pectus excavatum .

Back  -    New Search

furor (fewr-or) n.

indiscriminate violence and destructiveness, occurring especially during a period of mental confusion due to epilepsy.

Back  -    New Search

furuncle (fewr-ung-kl) n.

see BOIL.

Back  -    New Search

furunculosis (fewr-unk-yoo-loh-sis) n.

the occurrence of several boils (furuncles) at the same time, usually caused by Staphylococcus aureus infection.

Back  -    New Search

fusidic acid (few-sid-ik) n.

a steroid antibiotic used in the form of its salt, sodium fusidate, against penicillin-resistant staphylococci. It is usually administered by mouth, in conjunction with another antibiotic (such as flucloxacillin). Trade name: Fucidin .

Back  -    New Search

fusiform (few-zi-form) adj.

spindle-shaped; tapering at both ends.

Back  -    New Search

fusion (few-zhn) n.

1 the joining together of two structures by surgery. For example, fusion of two or more vertebrae is performed to stabilize an unstable spine.

2 the joining together of two structures by growth. Fusion of the epiphyses during development is the cause of arrested growth of stature.
Top

Back  -    New Search

G

GABA

see GAMMA AMINOBUTYRIC ACID.

Back  -    New Search

gag (gag) n.

(in medicine) an instrument that is placed between a patient's teeth to keep his mouth open.

Back  -    New Search

gait (gayt) n.

a manner of walking. ataxic g. an unsteady uncoordinated walk due to disease of the sensory nerves or cerebellum. See ATAXIA. cerebellar g. a staggering walk due to disease of the cerebellum. spastic g. a stiff shuffling walk in which the legs are held together.

Back  -    New Search

galact- (galacto-) prefix

denoting 1 milk.

2 galactose.
Top

Back  -    New Search

galactagogue (g-lak-t-gog) n.

an agent that stimulates the secretion of milk or increases milk flow.

Back  -    New Search

galactocele (g-lak-toh-seel) n.

1 a breast cyst containing milk, caused by closure of a milk duct.

2 an accumulation of milky liquid in the sac surrounding the testis (see HYDROCELE).
Top

Back  -    New Search

galactorrhoea (g-lak-t-ree-) n.

1 abnormally copious milk secretion.

2 secretion of milk after breast feeding has been stopped.
Top

Back  -    New Search

galactosaemia (g-lak-toh-see-mi) n.

an inborn inability to utilize the sugar galactose, which in consequence accumulates in the blood. Untreated, affected infants fail to thrive and become mentally retarded, but if galactose is eliminated from the diet growth and development may be normal.

Back  -    New Search

galactose (g-lak-tohz) n.

a simple sugar and a constituent of the milk sugar lactose. Galactose is converted to glucose in the liver.

Back  -    New Search

galea (gay-li) n.

1 a helmet-shaped anatomical part.

2 a type of head bandage.
Top

Back  -    New Search

galenical (g-len-ikl) n.

a pharmaceutical preparation of a drug of animal or plant origin.

Back  -    New Search

gallamine (gal--meen) n.

a drug administered by injection to produce muscle relaxation during anaesthesia (see MUSCLE RELAXANT). It is also used in a diagnostic test for myasthenia gravis. Trade name: Flaxedil .

Back  -    New Search

gall bladder (gawl) n.

a pear-shaped sac (7–10 cm long), lying underneath the right lobe of the liver, in which bile is stored. The gall bladder is a common site of stone formation (see GALLSTONE).

Back  -    New Search

Gallie's operation (gal-iz) n.

an operation in which strips of fascia taken from the thigh are used as suturing material to repair a hernia. [W. E. Gallie (1882–1959), Canadian surgeon]

Back  -    New Search

gallipot (gal-i-pot) n.

a small pot for holding lotions or ointments.

Back  -    New Search

gallium (gal-im) n.

a silvery metallic element. A radioisotope of gallium is used for the detection of lymphomas and areas of infection (such as an abscess) following intravenous injection. Symbol: Ga.

Back  -    New Search

gallstone (gawl-stohn) n.

a hard mass composed of bile pigments, cholesterol, and calcium salts, in varying proportions, that can form in the gall bladder. They may cause severe pain (see BILIARY (COLIC)) or they may pass into the common bile duct and cause obstructive jaundice or cholangitis. Treatment is usually by surgical removal of the gall bladder (see CHOLECYSTECTOMY) or by removing the stones themselves, which can be either dissolved using bile salts given by mouth, or shattered by ultrasound waves.

Back  -    New Search

galvanism (gal-v-nizm) n.

(formerly) any form of medical treatment using electricity. interrupted g. a form of electrotherapy in which direct current is used to stimulate the activity of nerves or the muscles they supply. See also FARADISM.

Back  -    New Search

galvanometer (gal-v-nom-it-er) n.

an instrument for measuring the strength of an electric current.

Back  -    New Search

gamete (gam-eet) n.

a mature sex cell: the ovum of the female or the spermatozoon of the male. Gametes are haploid, containing half the normal number of chromosomes.

Back  -    New Search

gamete intrafallopian transfer (GIFT) (intr-f-loh-pin) n.

a procedure for assisting conception, suitable for women whose Fallopian tubes are normal but in whom some other factor, such as endometriosis, prevents conception. Using needle aspiration, under laparoscopic or ultrasonic guidance, ova are removed from the ovary. After being mixed with the partner's spermatozoa, they are introduced into a Fallopian tube, where fertilization takes place. The fertilized ovum is subsequently implanted in the uterus.

Back  -    New Search

gametocide (gam-i-toh-syd) n.

a drug that kills gametocytes.

Back  -    New Search

gametocyte (g-meet-oh-syt) n.

any of the cells that are in the process of developing into gametes by undergoing gametogenesis.

Back  -    New Search

gametogenesis (gam-i-toh-jen-i-sis) n.

the process by which spermatozoa and ova are formed. In both sexes the precursor cells undergo meiosis, which halves the number of chromosomes. See OOGENESIS, SPERMATOGENESIS.

Back  -    New Search

gamgee tissue (gam-jee) n.

a thick layer of absorbent cotton between two layers of gauze, used as a surgical dressing.

Back  -    New Search

gamma aminobutyric acid (GABA) (gam- -meen-oh-bew-ti-rik) n.

an amino acid found in the central nervous system, predominantly in the brain, where it acts as an inhibitory neurotransmitter.

Back  -    New Search

gamma benzene hexachloride (heks--klor-ryd) n.

an insecticide used in creams, lotions, solutions, or shampoos to treat infestations caused by scabies, mites, and lice.

Back  -    New Search

gamma camera n.

a piece of apparatus that detects radioactivity in the form of gamma rays emitted by radioactive isotopes that have been introduced into the body as tracers. The position of the source of the radioactivity can be plotted and displayed on a TV monitor or photographic film. See SCINTILLATOR.

Back  -    New Search

gammaglobulin (gam--glob-yoo-lin) n.

any of a class of proteins (see GLOBULIN) present in the blood plasma. Almost all gammaglobulins are immunoglobulins.

Back  -    New Search

gamma rays pl. n.

electromagnetic radiation of wavelengths shorter than X-rays, given off by certain radioactive substances. Gamma rays are harmful to living tissues and can be used to sterilize certain materials and to kill bacteria as a means of food preservation. Controlled doses are used in radiotherapy.

Back  -    New Search

gamo- prefix

denoting marriage.

Back  -    New Search

ganciclovir (gan-sy-kloh-veer) n.

an antiviral drug used to treat severe cytomegalovirus infections, mainly in patients with AIDS. It is administered by injection. Trade name: Cymevene .

Back  -    New Search

gangli- (ganglio-) prefix

denoting a ganglion.

Back  -    New Search

ganglion (gang-li-n) n. (pl. ganglia)

1 (in neurology) any structure containing a collection of nerve cell bodies and often also numbers of synapses. Ganglia are found in the sympathetic and parasympathetic nervous systems. Within the central nervous system certain well-defined masses of nerve cells are called ganglia (see BASAL GANGLIA).

2 an abnormal but harmless swelling (cyst) that sometimes forms in tendon sheaths, especially at the wrist.
Top

Back  -    New Search

ganglionectomy (gang-li-n-ek-tmi) n.

surgical removal of a ganglion cyst.

Back  -    New Search

gangrene (gang-reen) n.

death and decay of part of the body due to deficiency or cessation of blood supply. The causes include disease, injury, or atheroma in major blood vessels, frostbite or severe burns, and diseases such as diabetes mellitus and Raynaud's disease. dry g. death and withering of tissues caused simply by a cessation of local blood circulation. moist g. death and putrefactive decay of tissue caused by bacterial infection. See also GAS GANGRENE.

Back  -    New Search

Ganser state (pseudodementia) (gan-ser) n.

a syndrome characterized by approximate answers, i.e. the patient gives absurdly false replies to questions, but the reply shows that the question has been understood. The condition is due to conversion disorder or to conscious malingering. [S. J. M. Ganser (1853–1931), German psychiatrist]

Back  -    New Search

Gardnerella (gard-ner-el-) n.

a genus of anaerobic bacteria. G. vaginalis a cause of vaginitis and, in pregnant women, of late miscarriage.

Back  -    New Search

Gardner's syndrome (gard-nerz) n.

a variant form of familial adenomatous polyposis in which polyps in the colon are associated with fibromas and osteomas (benign tumours), especially of the skull and jaw, and multiple sebaceous cysts. [E. J. Gardner (1909– ), US physician]

Back  -    New Search

gargle (gar-gl)

1 n. a medicated solution used for washing the mouth and throat.

2 vb. to apply a gargle by holding it in the throat and exhaling through it.
Top

Back  -    New Search

gargoylism (gar-goil-izm) n.

see HUNTER'S SYNDROME, HURLER'S SYNDROME.

Back  -    New Search

gas (gas) n.

a fluid whose physical state is such that the forces of attraction between its constituent atoms and molecules are very weak. It therefore has no definite shape or volume. laughing g. see NITROUS OXIDE.

Back  -    New Search

gas gangrene n.

death and decay of wound tissue infected by the soil bacterium Clostridium per fringens. Toxins produced by the bacterium cause putrefactive decay of connective tissue with the generation of gas.

Back  -    New Search

Gasserian ganglion (gas-eer-in) n.

a ganglion on the sensory root of the trigeminal nerve, deep within the skull. [J. L. Gasser (1723–65), Austrian anatomist]

Back  -    New Search

gastr- (gastro-) prefix

denoting the stomach.

Back  -    New Search

gastralgia (gas-tral-ji) n.

pain in the stomach.

Back  -    New Search

gastrectomy (gas-trek-tmi) n.

a surgical operation in which the whole or a part of the stomach is removed. partial (or subtotal ) g. an operation in which the upper third or half of the stomach is joined to the duodenum or small intestine. See also BILLROTH'S OPERATION. total g. an operation usually performed for stomach cancer, in which the oesophagus is joined to the duodenum.

Back  -    New Search

gastric (gas-trik) adj.

relating to or affecting the stomach. g. glands tubular glands in the mucous membrane of the stomach wall that secrete gastric juice. g. juice the liquid secreted by the gastric glands, containing hydrochloric acid, mucin, rennin, and pepsinogen. The acid acts on pepsinogen to produce the digestive enzyme pepsin. The acidity of the stomach contents also kills unwanted bacteria and other organisms that have been ingested with the food. g. ulcer an ulcer in the stomach, caused by the action of acid, pepsin, and bile on the stomach lining. Symptoms include vomiting and pain in the upper abdomen soon after eating, and such complications as bleeding (see HAEMATEMESIS), perforation, and obstruction due to scarring may occur. See also HELICOBACTER.

Back  -    New Search

gastrin (gas-trin) n.

a hormone produced in the mucous membrane of the pyloric region of the stomach. Its secretion is stimulated by the presence of food. It is circulated in the blood to the rest of the stomach, where it stimulates the production of gastric juice.

Back  -    New Search

gastrinoma (gas-tri-noh-m) n.

a rare tumour that secretes excess amounts of the hormone gastrin, causing the Zollinger-Ellison syndrome. Such tumours most frequently occur in the pancreas; about half of them are malignant.

Back  -    New Search

gastritis (gas-try-tis) n.

inflammation of the lining (mucosa) of the stomach. acute g. gastritis in which vomiting occurs, caused by ingesting excess alcohol or other irritating or corrosive substances. atrophic g. gastritis in which the stomach lining is atrophied. chronic g. gastritis that is usually caused by the bacterium Helicobacter pylori but may be associated with smoking and chronic alcoholism or be caused by bile entering the stomach from the duodenum. It has no definite symptoms, but the patient is liable to develop gastric ulcers or stomach cancer.

Back  -    New Search

gastrocele (gas-troh-seel) n.

a hernia of the stomach.

Back  -    New Search

gastrocnemius (gas-trok-nee-mis) n.

a muscle that forms the greater part of the calf of the leg. It flexes the knee and foot (so that the toes point downwards).

Back  -    New Search

gastrocolic reflex (gas-troh-kol-ik) n.

a wave of peristalsis produced in the colon by introducing food into a fasting stomach.

Back  -    New Search

gastroduodenoscopy (gas-troh-dew--di-nos-k-pi) n.

the technique of viewing the inside of the stomach and duodenum with a fibreoptic or video endoscope.

Back  -    New Search

gastroduodenostomy (gas-troh-dew--di-nost-mi) n.

a surgical operation in which the duodenum is joined to an opening made in the stomach in order to bypass an obstruction or to facilitate the exit of food from the stomach after vagotomy. See also DUODENOSTOMY.

Back  -    New Search

gastroenteritis (gas-troh-enter-I-tis) n.

inflammation of the stomach and intestine. It is usually due to acute infection by viruses or bacteria or to food-poisoning toxins and causes vomiting and diarrhoea. Fluid loss is sometimes severe, especially in infants, and intravenous fluid replacement may be necessary.

Back  -    New Search

gastroenterology (gas-troh-enter-ol-ji) n.

the study of gastrointestinal disease, which includes disease of any part of the digestive tract and also of the liver, biliary tract, and pancreas.

Back  -    New Search

gastroenterostomy (gas-troh-enter-ost-mi) n.

a surgical operation in which the small intestine is joined to an opening made in the stomach. The usual technique is gastroduodenostomy.

Back  -    New Search

gastroileac reflex (gas-troh-il-i-ak) n.

the relaxation of the ileocaecal valve caused by the presence of food in the stomach.

Back  -    New Search

gastrojejunostomy (gas-troh-ji-joo-nost-mi) n.

a surgical operation in which the jejunum is joined to an opening made in the stomach.

Back  -    New Search

gastrolith (gas-tr-lith) n.

a stone in the stomach, which usually builds up around a bezoar.

Back  -    New Search

gastro-oesophageal reflux (gas-troh-ee-sof--jee-l) n.

a condition in which the stomach contents reflux into the oesophagus because of impairment of the usual mechanisms preventing this. g.-o.r. disease the syndrome caused by abnormal gastro-oesophageal reflux, including symptoms of heartburn, regurgitation, and odynophagia, in which oesophagitis may be present.

Back  -    New Search

gastropexy (gas-troh-peks-i) n.

surgical attachment of the stomach to the abdominal wall.

Back  -    New Search

gastroplasty (gas-troh-plasti) n.

surgical alteration of the shape of the stomach without removal of any part, especially in order to reduce the size of the stomach in the treatment of morbid obesity.

Back  -    New Search

gastroptosis (gas-trop-toh-sis) n.

a condition in which the stomach hangs low in the abdomen.

Back  -    New Search

gastroschisis (gas-tros-ki-sis) n.

a congenital defect in the abdominal wall, which fails to close to the right of a normal umbilical cord. Gut prolapses through the defect and has no covering.

Back  -    New Search

gastroscope (gas-tr-skohp) n.

an illuminated optical instrument used to inspect the interior of the stomach. Modern instruments transmit the image through a fibreoptic bundle or by a tiny video camera, allowing all areas of the stomach to be seen and photographed and specimens to be taken for microscopic examination. Therapeutic procedures may be performed.
—gastroscopy (gas-tros-k-pi) n.

Back  -    New Search

gastrostomy (gas-trost-mi) n.

a surgical procedure in which an opening is made into the stomach from the outside. It is usually performed to allow food and fluid to be poured directly into the stomach when swallowing is impossible because of disease or obstruction of the oesophagus.

Back  -    New Search

gastrotomy (gas-trot-mi) n.

a procedure during abdominal surgery in which the stomach is opened, usually to allow inspection of the interior, to remove a foreign body, or to allow the oesophagus to be approached from below.

Back  -    New Search

gastrula (gas-troo-l) n.

an early stage in the development of many animal embryos. The gastrula consists of a double-layered ball of cells formed by invagination and movement of cells in the preceding single-layered stage (blastula) in the process of gastrulation .

Back  -    New Search

Gaucher's disease (goh-shayz) n.

a genetically determined disease, inherited as a recessive condition, resulting from the deposition of fatty compounds in the brain and other tissues (especially bone). It causes mental retardation, abnormal limb posture and spasticity, and difficulty with swallowing. [P. C. E. Gaucher (1854–1918), French physician]

Back  -    New Search

gauze (gawz) n.

thin open-woven material used in several layers for the preparation of dressings and swabs.

Back  -    New Search

gavage (gav-ahzh) n.

forced feeding: any means used to get an unwilling or incapacitated patient to take in food by mouth, especially via a stomach tube.

Back  -    New Search

Geiger counter (gy-ger kownt-er) n.

a device for detecting and measuring the level of radioactivity of a substance. [H. Geiger (1882–1945), German physicist]

Back  -    New Search

gel (jel) n.

a colloidal suspension that has set to form a jelly. Some insoluble drugs are administered in the form of gels.

Back  -    New Search

gelatin (jel--tin) n.

a jelly-like substance formed when tendons, ligaments, etc. containing collagen are boiled in water. Gelatin has been used in medicine as a source of dietary protein, in pharmacy for the manufacture of capsules and suppositories, and in bacteriology for preparing culture media.

Back  -    New Search

gemeprost (jem--prost) n.

a prostaglandin drug, administered as a vaginal pessary to terminate pregnancy. It causes powerful contractions of the uterus at any stage of pregnancy. Trade name: Cervagem .

Back  -    New Search

gemfibrozil (jem-fy-broh-zil) n.

a drug used to lower very low-density lipoproteins in patients with high triglyceride serum levels who have not responded to diet, weight reduction, or exercise. It is administered by mouth. Trade name: Lopid .

Back  -    New Search

gene (jeen) n.

the basic unit of genetic material, which is carried at a particular place on a chromosome. Originally it was regarded as the unit of inheritance and mutation but is now usually defined as a sequence of DNA or RNA that acts as the unit controlling the formation of a single polypeptide chain. In diploid organisms, including man, genes occur as pairs of alleles (see DOMINANT, RECESSIVE). See also (GENE) CLONE, GENE THERAPY.

Back  -    New Search

generalized anxiety disorder (jen-er--lyzd) n.

a state of inappropriate and sometimes severe anxiety, without adequate cause, that lasts for at least six months. Symptoms include breathlessness, palpitations, sweating, clammy hands, dry mouth, and globus hystericus. Treatment is with beta blockers, antihistamines, and antidepressants.

Back  -    New Search

general paralysis of the insane (GPI) (jen-er-l) n.

a late consequence of syphilitic infection. The symptoms are those of a dementia and spastic weakness of the limbs. Deafness, epilepsy, and dysarthria may occur.

Back  -    New Search

general practitioner (GP) (prak-tish-n-er) n.

a doctor who is the main agent of primary health care, through whom patients make first contact with health services for a new episode of illness or fresh developments of chronic diseases. Advice and treatment are provided for those who do not require the expertise of a consultant or other specialist services of hospitals (see SECONDARY HEALTH CARE). See also GROUP PRACTICE.

Back  -    New Search

generic (jin-e-rik) adj.

1 denoting a drug name that is not protected by a trademark.

2 of or relating to a genus.
Top

Back  -    New Search

-genesis suffix

denoting origin or development.

Back  -    New Search

gene therapy n.

treatment directed to curing genetic disease by introducing normal genes into patients to overcome the effects of defective genes, using techniques of genetic engineering. At present, gene therapy is most feasible for treating disorders caused by a defect in a single recessive gene, such as adenosine deaminase (ADA) deficiency and cystic fibrosis. Gene therapy for certain types of cancer is also undergoing clinical trials.

Back  -    New Search

genetic code (ji-net-ik) n.

the information carried by DNA and messenger RNA that determines the sequence of amino acids in every protein and thereby controls the nature of all proteins made by the cell.

Back  -    New Search

genetic counselling n.

the procedure by which patients and their families are given advice about the nature and consequences of inherited disorders, the possibility of becoming affected or having affected children, and the various options that are available to them for the prevention, diagnosis, and management of such conditions.

Back  -    New Search

genetic engineering (recombinant DNA technology) n.

the techniques involved in altering the characteristics of an organism by inserting genes from another organism into its DNA. This altered DNA is known as recombinant DNA . For example, the human genes for insulin, interferon, and growth hormone production have been incorporated into bacterial DNA to enable the commercial production of these substances.

Back  -    New Search

genetics (ji-net-iks) n.

the science of inheritance. It attempts to explain the differences and similarities between related organisms and the ways in which characters are passed from parents to their offspring. See also CYTOGENETICS, MENDEL'S LAWS.

Back  -    New Search

genetic screening n.

screening tests to discover individuals whose genotypes are associated with specific diseases. Such individuals may later develop the disease itself or pass it on to their children (see CARRIER).

Back  -    New Search

geni- (genio-) prefix

denoting the chin.

Back  -    New Search

-genic suffix

denoting 1 producing.

2 produced by.
Top

Back  -    New Search

genicular (ji-nik-yoo-ler) adj.

relating to the knee joint: applied to arteries that supply the knee.

Back  -    New Search

genital (jen-i-t'l) adj.

relating to the reproductive organs or to reproduction.

Back  -    New Search

genitalia (jen-i-tay-li) pl. n.

the reproductive organs of either the male or the female, particularly the external parts of the reproductive system. See also VULVA.

Back  -    New Search

genito- prefix

denoting the reproductive organs.

Back  -    New Search

genitourinary (jen-i-toh-yoor-in-er-i) adj.

of or relating to the organs of reproduction and excretion. g. medicine the branch of medicine concerned with the study and treatment of sexually transmitted diseases.

Back  -    New Search

genodermatosis (jen-oh-der-m-toh-sis) n.

any genetically determined skin disorder, such as ichthyosis, neurofibromatosis, or xeroderma pigmentosum.

Back  -    New Search

genome (jen-ohm) n.

the total genetic material of an organism, comprising the genes contained in its chromosomes; sometimes the term is used for the basic haploid set of chromosomes of an organism. The human genome comprises 23 pairs of chromosomes.

Back  -    New Search

genotype (jen-oh-typ) n.

1 the genetic constitution of an individual or group, as determined by the particular set of genes it possesses.

2 the genetic information carried by a pair of alleles, which determines a particular characteristic. Compare PHENOTYPE.
Top

Back  -    New Search

gentamicin (jen-t-my-sin) n.

an aminoglycoside antibiotic used to treat infections caused by a wide range of bacteria. It can be administered by injection or applied in a cream to the skin or in drops to the ears and eyes. Trade names: Cidomycin , Garamycin , Genticin .

Back  -    New Search

gentian violet (jen-shn vy--lit) n.

a dye used to stain tissues and microorganisms for microscopical study and also as a topically applied antiseptic.

Back  -    New Search

genu (jen-yoo) n.

1 the knee. g. valgum see KNOCK-KNEE. g. varum see BOW-LEGS.

2 any bent anatomical structure resembling the knee.
Top

—genual adj.

Back  -    New Search

genucubital position (knee-elbow position) (jen-yoo-kew-bit'l) n.

the buttocks-up position commonly assumed by patients undergoing anorectal examinations.

Back  -    New Search

genupectoral position (knee-chest position) (jen-yoo-pek-ter-l) n.

the position of a patient in which the weight of the body is supported on the knees and chest. See POSITION.

Back  -    New Search

genus (jen-s) n. (pl. genera)

a category used in the classification of animals and plants. A genus consists of several closely related and similar species; for example the genus Canis includes the dog, wolf, and jackal.

Back  -    New Search

ger- (gero-, geront(o)-) prefix

denoting old age.

Back  -    New Search

geriatrics (je-ri-at-riks) n.

the branch of medicine concerned with the diagnosis and treatment of disorders that occur in old age and with the care of the aged. See also GERONTOLOGY
—geriatrician (je-ri--trish-n) n.

Back  -    New Search

germ (jerm) n.

any microorganism, especially one that causes disease. See also INFECTION.

Back  -    New Search

German measles (jer-mn) n.

a mild highly contagious virus infection, mainly of childhood. Symptoms include headache, sore throat, and slight fever, followed by swelling and soreness of the neck and the eruption of a rash of minute pink spots, spreading from the face and neck to the rest of the body. German measles can cause fetal malformations during early pregnancy. Medical name: rubella. Compare SCARLET FEVER.

Back  -    New Search

germ cell (gonocyte) n.

1 any of the embryonic cells that have the potential to develop into spermatozoa or ova.

2 a gamete.
Top

Back  -    New Search

germicide (jerm-i-syd) n.

an agent that destroys microorganisms, particularly those causing disease. See ANTIBIOTIC, ANTIFUNGAL, ANTISEPTIC, DISINFECTANT.

Back  -    New Search

germinal (jer-min-l) adj.

1 relating to the early developmental stages of an embryo or tissue.

2 relating to a germ.
Top

Back  -    New Search

germ layer n.

any of the three distinct types of tissue found in the very early stages of embryonic development (see ECTODERM, ENDODERM, MESODERM).

Back  -    New Search

gerontology (je-ron-tol-ji) n.

the study of the changes in the mind and body that accompany ageing and the problems associated with them.

Back  -    New Search

gestaltism (gsh-talt-izm) n.

a school of psychology that regards mental processes as wholes (gestalts ) that cannot be broken down into constituent parts. From this was developed gestalt therapy , which aims at achieving a suitable gestalt within the patient that includes all facets of functioning.

Back  -    New Search

gestation (jes-tay-shn) n.

the period during which a fertilized egg cell develops into a baby that is ready to be delivered. See also PREGNANCY.

Back  -    New Search

gestodene (jes-toh-deen) n.

a progestogen used in oral contraceptives in combination with an oestrogen. Trade names: Femodene , Minulet .

Back  -    New Search

GFR n.

see GLOMERULAR FILTRATION RATE.

Back  -    New Search

Ghon's focus (gonz) n.

the lesion produced in the lung of a previously uninfected person by tubercle bacilli. It is a small focus of granulomatous inflammation, which may become visible on a chest X-ray if it grows large enough or if it calcifies. [A. Ghon (1866–1936), Czech pathologist]

Back  -    New Search

giant cell (jy-nt) n.

any large cell, such as a megakaryocyte. Giant cells may have one or many nuclei.

Back  -    New Search

giant-cell arteritis n.

see ARTERITIS.

Back  -    New Search

giardiasis (lambliasis) (jy-ar-dy--sis) n.

a disease caused by the parasitic protozoan Giardia lamblia in the small intestine. Symptoms include diarrhoea, nausea, bellyache, flatulence, and the passage of pale fatty stools (steatorrhoea). The disease is particularly common in children; it responds well to oral doses of quinacrine and metronidazole.

Back  -    New Search

gibbus (gibbosity) (gib-s) n.

a sharply angled curvature of the backbone, resulting from collapse of a vertebra. Infection with tuberculosis was a common cause.

Back  -    New Search

GIFT n.

see GAMETE INTRAFALLOPIAN TRANSFER.

Back  -    New Search

gigantism (jy-gan-tizm) n.

abnormal growth causing excessive height, most commonly due to oversecretion during childhood of growth hormone (somatotrophin) by the pituitary gland. See also ACROMEGALY.

Back  -    New Search

Gilbert's syndrome (zheel-bairz) n.

familial unconjugated hyperbilirubinaemia: a condition caused by an inherited congenital deficiency of the enzyme UDP glucuronyl transferase in the liver cells. Patients become mildly jaundiced, especially if they fast or have some minor infection. [N. A. Gilbert (1858–1927). French physician]

Back  -    New Search

Gilles de la Tourette syndrome (Tourette syndrome) (zheel d la toor-et) n.

a condition of severe and multiple tics, including vocal tics, grunts, and involuntary obscene speech (coprolalia). The patient may also involuntarily repeat the words or imitate the actions of others (see PALILALIA). The condition usually starts in childhood and becomes chronic; the causes are unknown. [G. Gilles de la Tourette (1857–1904), French neurologist]

Back  -    New Search

Gilliam's operation (gil-i-mz) n.

an operation to correct retroversion of the uterus in which the round ligaments are shortened. [D. T. Gilliam (1844–1923), US gynaecologist]

Back  -    New Search

gingiv- (gingivo-) prefix

denoting the gums.

Back  -    New Search

gingiva (jin-jiv-) n. (pl. gingivae)

the gum: the layer of dense connective tissue and overlying mucous membrane that covers the alveolar bone and necks of the teeth.
—gingival adj.

Back  -    New Search

gingivectomy (jin-ji-vek-tmi) n.

the surgical removal of excess gum tissue. It is a specific procedure of periodontal surgery.

Back  -    New Search

gingivitis (jin-ji-vy-tis) n.

inflammation of the gums, which become swollen and bleed easily, caused by plaque at the necks of the teeth.

Back  -    New Search

ginglymus (hinge joint) (jing-li-ms) n.

a form of diarthrosis that allows angular movement in one plane only. Examples are the knee joint and the elbow joint.

Back  -    New Search

girdle (ger-d'l) n.

(in anatomy) an encircling or arching arrangement of bones. See also PELVIC GIRDLE, SHOULDER GIRDLE.

Back  -    New Search

Girdlestone's operation (ger-d'l-stohnz) n.

an operation in which the head of the femur and part of the acetabulum are removed and a mass of muscle is sutured between the bone ends. It is performed for osteoarthritis. [G. R. Girdlestone (1881–1950), British surgeon]

Back  -    New Search

glabella (gl-bel-) n.

the smooth rounded surface of the frontal bone in the middle of the forehead, between the two eyebrows.

Back  -    New Search

gladiolus (glad-i-oh-ls) n.

the middle and largest segment of the sternum.

Back  -    New Search

gland (gland) n.

an organ or group of cells that is specialized for synthesizing and secreting certain fluids, either for use in the body or for excretion. See ENDOCRINE GLAND, EXOCRINE GLAND, SECRETION.

Back  -    New Search

glanders (equinia) (glan-derz) n.

an infectious disease of horses, donkeys, and mules that is caused by the bacterium Pseudomonas mallei and can be transmitted to man. Symptoms include fever and inflammation of the lymph nodes (a form of the disease known as farcy ), skin, and nasal mucous membranes. Administration of sulphonamides or streptomycin is usually effective.

Back  -    New Search

glandular fever (glan-dew-ler) n.

an infectious disease, caused by the Epstein-Barr virus, that affects the lymph nodes in the neck, armpits, and groin; it mainly affects adolescents and young adults. Symptoms include swelling and tenderness of the lymph nodes, fever, headache, a sore throat, lethargy, and loss of appetite. Glandular fever is diagnosed by the presence of large numbers of monocytes in the blood. Medical name: infectious mononucleosis .

Back  -    New Search

glans (glans penis) (glanz) n.

the acornshaped end part of the penis, formed by the expanded end of the corpus spongiosum. The term glans is also applied to the end of the clitoris.

Back  -    New Search

glare (glair) n.

the undesirable effects of scattered stray light on the retina, causing reduced contrast and visual performance as well as annoyance and discomfort.

Back  -    New Search

Glasgow scoring system (Glasgow coma scale) (glahz-goh skor-ing) n.

a numerical system used to estimate a patient's level of consciousness after head injury. Each of the following are numerically graded: eye opening (4), motor response (6), and verbal response (5). The higher the score, the greater the level of consciousness: a score of 7 indicates a coma.

Back  -    New Search

glaucoma (glaw-koh-m) n.

a condition in which loss of vision occurs because of an abnormally high pressure in the eye. angle-closure (or acute ) g. primary glaucoma in which there is a sudden rise in pressure due to blockage of the angle between the junction of the cornea and sclera and the margin of the iris, where aqueous humour usually drains from the eye. It is accompanied by pain and marked blurring of vision. open-angle (or chronic simple ) g. a more common form of primary glaucoma in which the pressure increases gradually, usually without producing pain, and the visual loss is insidious. primary g. glaucoma that occurs without any other ocular disease. It is an important cause of blindness. secondary g. glaucoma that may occur when other ocular disease impairs the normal circulation of the aqueous humour and causes the intraocular pressure to rise.

Back  -    New Search

gleet (gleet) n.

a discharge of purulent mucus from the penis or vagina resulting from chronic gonorrhoea.

Back  -    New Search

glenohumeral (glee-noh-hew-mer-l) adj.

relating to the glenoid cavity and the humerus: the region of the shoulder joint.

Back  -    New Search

glenoid cavity (glenoid fossa) (glee-noid) n.

the socket of the shoulder joint: the pear-shaped cavity at the top of the scapula into which the head of the humerus fits.

Back  -    New Search

gli- (glio-) prefix

denoting 1 glia.

2 a glutinous substance.
Top

Back  -    New Search

glia (neuroglia) (glee-) n.

the special connective tissue of the central nervous system. Glial cells outnumber the neurones by between five and ten to one, and make up some 40% of the total volume of the brain and spinal cord.
—glial adj.

Back  -    New Search

glibenclamide (gly-ben-kl-myd) n.

a drug that reduces the level of sugar in the blood and is administered by mouth to treat noninsulin-dependent diabetes (see SULPHONYLUREA). Trade names: Daonil , Euglucon .

Back  -    New Search

gliclazide (gly-kl-zyd) n.

a sulphonylurea oral hypoglycaemic drug used in the treatment of noninsulin-dependent (Type II) diabetes. Trade name: Diamicron .

Back  -    New Search

glioblastoma (spongioblastoma) (gly-oh-blast-oh-m) n.

the most aggressive type of brain tumour derived from glial tissue. Its rapid enlargement destroys normal brain cells, with a progressive loss of function, and raises the intracranial pressure, causing headache, vomiting, and drowsiness.

Back  -    New Search

glioma (gly-oh-m) n.

any tumour of glial cells in the nervous system. The term is sometimes used for all tumours that arise in the central nervous system.

Back  -    New Search

gliomyoma (gly-oh-my-oh-m) n.

a tumour composed of nervous and muscular tissue.

Back  -    New Search

glipizide (glip-i-zyd) n.

a drug used to control high blood-glucose levels (hyperglycaemia) in patients with noninsulin-dependent diabetes after diet control has failed (see SULPHONYLUREA). It is administered by mouth. Trade names: Glibenese , Minodiab .

Back  -    New Search

globin (gloh-bin) n.

a protein, found in the body, that can combine with iron-containing groups to form haemoglobin and myohaemoglobin.

Back  -    New Search

globulin (glob-yoo-lin) n.

one of a group of simple proteins that are soluble in dilute salt solutions and can be coagulated by heat. serum g. any of the different globulins present in the blood, including gammaglobulins. Some have important functions as antibodies (see IMMUNOGLOBULIN).

Back  -    New Search

globulinuria (glob-yoo-lin-yoor-i) n.

the presence in the urine of globulins.

Back  -    New Search

globus (gloh-bs) n.

a spherical or globe-shaped anatomical structure. g. hystericus the sensation of having a lump in the throat that cannot be swallowed, sometimes occurring in anxiety states, emotional conflict, and hysteria.

Back  -    New Search

glomangioma (glomus tumour) (gloh-man-ji-oh-m) n.

see GLOMUS.

Back  -    New Search

glomerular filtration rate (GFR) (glom-e-roo-ler) n.

the rate at which substances are filtered from the blood of the glomeruli into the Bowman's capsules of the nephrons. It is calculated by measuring the clearance of specific substances (e.g. creatinine) and is an index of renal function.

Back  -    New Search

glomerulitis (glom-e-roo-ly-tis) n.

any one of a variety of lesions of the glomeruli associated with acute or chronic kidney disease.

Back  -    New Search

glomerulonephritis (glomerular nephritis) (glom-e-roo-loh-ni-fry-tis) n.

any of a group of kidney diseases involving the glomeruli (see GLOMERULUS), usually thought to be the result of antibody-antigen reactions that localize in the kidneys because of their filtering function. Acute nephritis is marked by blood in the urine and fluid and urea retention. It may be related to a recent streptococcal throat infection and usually settles completely, with rapid return of normal kidney function. Other forms of nephritis present with chronic haematuria or with the nephrotic syndrome; children often eventually recover completely, but adults are more likely to progress to chronic nephritis and eventual kidney failure.

Back  -    New Search

glomerulus (glom-e-roo-ls) n. (pl. glomeruli)

1 the network of blood capillaries contained within the cuplike end (Bowman's capsule) of a nephron. It is the site of primary filtration of waste products from the blood into the kidney tubule.

2 any other small rounded mass.
Top

—glomerular adj.

Back  -    New Search

glomus (gloh-ms) n. (pl. glomera)

a small communication between a tiny artery and a vein that is well supplied with sensory receptors. For example, glomera in the skin of the limbs are concerned with temperature regulation. g. jugulare a collection of chemoreceptors within a dilatation of the internal jugular vein at its origin at the base of the skull. g. tumour (glomangioma) a harmless but often painful tumour, usually occurring at the ends of the fingers or toes, caused by malformation or overgrowth of a glomus.

Back  -    New Search

gloss- (glosso-) prefix

denoting the tongue.

Back  -    New Search

glossa (glos-) n.

see TONGUE.

Back  -    New Search

glossectomy (glos-ek-tmi) n.

surgical removal of the tongue, an operation usually carried out for cancer in this structure.

Back  -    New Search

glossitis (glos-I-tis) n.

inflammation of the tongue.

Back  -    New Search

glossodynia (glos-oh-din-i) n.

pain in the tongue.

Back  -    New Search

glossopharyngeal nerve (glos-oh-fa-rin-jee-l) n.

the ninth cranial nerve (IX), which supplies motor fibres to part of the pharynx and to the parotid salivary glands and sensory fibres to the posterior third of the tongue and the soft palate.

Back  -    New Search

glossoplegia (glos-oh-plee-ji) n.

paralysis of the tongue.

Back  -    New Search

glottis (glot-iss) n.

the space between the two vocal folds. The term is often applied to the vocal folds themselves or to that part of the larynx associated with the production of sound.

Back  -    New Search

gluc- (gluco-) prefix

denoting glucose.

Back  -    New Search

glucagon (gloo-k-gon) n.

a hormone, produced by the pancreas, that causes an increase in the blood sugar level. Glucagon is administered by injection to counteract diabetic hypoglycaemia.

Back  -    New Search

glucagonoma (gloo-k-gn-oh-m) n.

a pancreatic tumour that secretes glucagon and produces attacks of hypoglycaemia.

Back  -    New Search

glucocorticoid (gloo-koh-kor-ti-koid) n.

any of a group of corticosteroids, including cortisone, that are essential for the utilization of carbohydrate, fat, and protein by the body. Naturally occurring and synthetic glucocorticoids have very powerful anti-inflammatory effects.

Back  -    New Search

gluconeogenesis (gloo-koh-nee-oh-jen-i-sis) n.

the biochemical process in which glucose is synthesized from non-carbohydrate sources, such as amino acids, when carbohydrate is not available in sufficient amounts in the diet.

Back  -    New Search

glucose (dextrose) (gloo-kohz) n.

a simple sugar containing six carbon atoms (a hexose). Glucose, an important source of energy, is one of the constituents of both sucrose and starch, both of which yield glucose after digestion. It is stored in the body in the form of glycogen. If the blood-glucose concentration falls below the normal level of around 5 mmol/1, neurological and other symptoms may result (see HYPOGLYCAEMIA). If the blood-glucose level is raised to 10 mmol/1, the condition of hyperglycaemia develops. This is a symptom of diabetes mellitus.

Back  -    New Search

glucose-6-phosphate dehydrogen-ase deficiency n.

a hereditary (X-linked) condition in which absence of the enzyme glucose-6-phosphate dehydrogenase (G6PD), which functions in carbohydrate metabolism, results in haemolysis, usually after exposure to oxidants (such as drugs) or infections. See also FAVISM.

Back  -    New Search

glucose tolerance test n.

a test used in the diagnosis of diabetes mellitus. A quantity of glucose is administered and the concentration of sugar in the blood and urine is determined at 30-minute intervals afterwards.

Back  -    New Search

glucoside (gloo-koh-syd) n.

see GLYCOSIDE.

Back  -    New Search

glucuronic acid (gloo-kewr-on-ik) n.

a sugar acid derived from glucose. Glucuronic acid is an important constituent of chondroitin sulphate (found in cartilage) and hyaluronic acid (found in synovial fluid).

Back  -    New Search

glue ear (gloo) n.

a common condition in which viscous fluid accumulates in the middle ear, causing deafness. It is most frequently seen in children and is due to a malfunctioning of the Eustachian tube. Many cases resolve spontaneously; treatment, if required, consists of surgical incision of the eardrum (myringotomy), drainage of the fluid, and insertion of a grommet. Medical name: secretory otitis media .

Back  -    New Search

glutamic acid (glutamate) (gloo-tam-ik) n.

see AMINO ACID.

Back  -    New Search

glutamic oxaloacetic transaminase (GOT) n.

see ASPARTATE AMINOTRANSFERASE (AST).

Back  -    New Search

glutamic pyruvic transaminase (GPT) n.

see ALANINE AMINOTRANSFERASE (ALT).

Back  -    New Search

glutaminase (gloo-tam-in-ayz) n.

an enzyme, found in the kidney, that catalyses the breakdown of the amino acid glutamine to ammonia and glutamic acid: a stage in the production of urea.

Back  -    New Search

glutamine (gloo-t-meen) n.

see AMINO ACID.

Back  -    New Search

gluten (gloo-tn) n.

a mixture of the two proteins gliadin and glutenin . Gluten is present in wheat and rye and is important for its baking properties. Sensitivity to gluten leads to coeliac disease in children.

Back  -    New Search

gluteus (gloo-tee-s) n.

one of three paired muscles of the buttocks (g. maximus , g. medius , and g. minimus ). They are responsible for movements of the thigh.
—gluteal adj.

Back  -    New Search

glyc- (glyco-) prefix

denoting sugar.

Back  -    New Search

glycerin (glycerol) (glis-er-in) n.

a clear viscous liquid obtained by hydrolysis of fats and mixed oils and produced as a byproduct in the manufacture of soap. It is used as an emollient in many skin preparations, as a laxative (particularly in the form of suppositories), and as a sweetening agent in the pharmaceutical industry.

Back  -    New Search

glyceryl trinitrate (nitroglycerin) (glis-er-il try-ny-trayt) n.

a drug that dilates blood vessels and is administered by mouth to prevent and treat angina (see VASODILATOR). Trade names: Nitrocontin , Sustac , Transiderm-Nitro .

Back  -    New Search

glycine (gly-seen) n.

see AMINO ACID.

Back  -    New Search

glycocholic acid (gly-koh-kol-ik) n.

see BILE ACIDS.

Back  -    New Search

glycogen (gly-koh-jn) n.

a carbohydrate consisting of branched chains of glucose units. Glycogen is the principal form in which carbohydrate is stored in the body (in liver and muscles); it may be readily broken down to glucose.

Back  -    New Search

glycogenesis (gly-koh-jen-i-sis) n.

the biochemical process, occurring chiefly in the liver and in muscle, by which glucose is converted into glycogen.

Back  -    New Search

glycogenolysis (gly-koh-j-nol-i-sis) n.

a biochemical process, occurring chiefly in the liver and in muscle, by which glycogen is broken down into glucose.

Back  -    New Search

glycolysis (gly-kol-i-sis) n.

the conversion of glucose, by a series of ten enzyme-catalysed reactions, to lactic acid, with the production of energy in the form of ATP.

Back  -    New Search

glycoprotein (gly-koh-proh-teen) n.

one of a group of compounds consisting of a protein combined with a carbohydrate (such as galactose or mannose). Examples of glycoproteins are certain enzymes, hormones, and antigens.

Back  -    New Search

glycoside (gly-koh-syd) n.

a compound formed by replacing the hydroxyl group (—OH) of a sugar by another group. (If the sugar is glucose the compound is known as a glucoside .) Glycosides found in plants include some pharmacologically important products (such as digitalis).

Back  -    New Search

glycosuria (gly-kohs-yoor-i) n.

the presence of glucose in the urine in abnormally large amounts. Glycosuria may be associated with diabetes mellitus, kidney disease, and some other conditions.

Back  -    New Search

gnath- (gnatho-) prefix

denoting the jaw.

Back  -    New Search

gnathoplasty (nath-oh-plasti) n.

plastic surgery of the jaw.

Back  -    New Search

GnRH n.

see GONADOTROPHIN-RELEASING HORMONE.

Back  -    New Search

GnRH analogue n.

see LHRH ANALOGUE.

Back  -    New Search

goal (gohl) n.

a statement of what the nursing intervention is intended to achieve, usually expressed in terms of the patient's expected behaviour. See BEHAVIOURAL OBJECTIVE, EXPECTED OUTCOME.

Back  -    New Search

goblet cell (gob-lit) n.

a column-shaped secretory cell found in the epithelium of the respiratory and intestinal tracts. Goblet cells secrete the principal constituents of mucus.

Back  -    New Search

goitre (goi-ter) n.

a swelling of the neck due to enlargement of the thyroid gland. This may be due to lack of dietary iodine, which is necessary for the production of thyroid hormone: the gland enlarges in an attempt to increase the output of hormone. Autoimmune thyroiditis can be associated with goitre (see HASHIMOTO'S DISEASE). exophthalmic g. (Graves' disease ) see THYROTOXICOSIS. sporadic g. goitre due to simple overgrowth (hyperplasia) of the gland or to a tumour.

Back  -    New Search

goitrogen (goi-troh-jen) n.

any substance that causes goitre.
—goitrogenic adj.

Back  -    New Search

gold (gohld) n.

(in pharmacology) any of several compounds of the metal gold, used in the treatment of rheumatoid arthritis. Sodium aurothiomalate (Myocrisin) is administered by intramuscular injection. Auranofin is a gold compound administered orally.

Back  -    New Search

golfer's elbow (golf-erz) n.

inflammation of the origin of the muscle on the inside of the elbow caused by overuse. Treatment is by rest, anti-inflammatory medication, or steroid injection. Compare TENNIS ELBOW.

Back  -    New Search

Golgi apparatus (gol-ji) n.

a collection of vesicles and folded membranes in a cell. It stores and later transports the proteins manufactured in the endoplasmic reticulum. [C. Golgi (1844–1926), Italian histologist]

Back  -    New Search

Golgi cells pl. n.

types of neurones (nerve cells) within the central nervous system. Golgi type I neurones have very long axons that connect different parts of the system; Golgi type II neurones have only short axons or sometimes none.

Back  -    New Search

gomphosis (gom-foh-sis) n.

a form of synarthrosis (immovable joint) in which a conical process fits into a socket.

Back  -    New Search

gonad (goh-nad) n.

a male or female reproductive organ, which produces the gametes. See OVARY, TESTIS.

Back  -    New Search

gonadorelin (gon--doh-rel-in) n.

a synthetic analogue of gonadotrophin-releasing hormone (see LHRH ANALOGUE), administered by intravenous injection to stimulate the production of pituitary gonadotrophins. It is used in the treatment of amenorrhoea and certain types of infertility.

Back  -    New Search

gonadotrophin (gonadotrophic hormone) (gon--doh-troh-fin) n.

any of several hormones synthesized and released by the pituitary gland, such as follicle-stimulating hormone and luteinizing hormone, that act on the gonads to promote production of sex hormones and either sperm or ova. See also HUMAN CHORIONIC GONADOTROPHIN.

Back  -    New Search

gonadotrophin-releasing hormone (GnRH) n.

a peptide hormone produced in the hypothalamus and transported via the bloodstream to the pituitary gland, where it controls the synthesis and release of other hormones, the pituitary gonadotrophins. GnRH analogue see LHRH ANALOGUE.

Back  -    New Search

gonagra (gon-ag-r) n.

gout in the knee.

Back  -    New Search

goni- (gonio-) prefix

denoting an anatomical angle or corner.

Back  -    New Search

goniopuncture (goh-ni-oh-punk-cher) n.

a rarely performed operation for congenital glaucoma (see BUPHTHALMOS) to enable fluid to be drawn from the eye. See GONIOTOMY.

Back  -    New Search

gonioscope (goh-ni-oh-skohp) n.

a special lens used for viewing the structures around the edge of the anterior chamber of the eye (in front of the iris).

Back  -    New Search

goniotomy (trabeculotomy) (goh-ni-ot-mi) n.

an operation for congenital glaucoma (see BUPHTHALMOS) in which a fine knife is used to make an incision into Schlemm's canal from within the eye. It is the first stage of goniopuncture.

Back  -    New Search

gonococcus (gon-oh-kok-s) n. (pl. gonococci)

the causative agent of gonorrhoea: the bacterium Neisseria gonorrhoeae.
—gonococcal adj.

Back  -    New Search

gonocyte (gon-oh-syt) n.

see GERM CELL.

Back  -    New Search

gonorrhoea (gon--ree-) n.

a sexually transmitted disease, caused by the bacterium Neisseria gonorrhoeae, that affects the genital mucous membranes of either sex. Symptoms include pain on passing urine and discharge of gleet. In untreated cases, the infection may spread throughout the reproductive system, causing sterility; severe inflammation of the urethra in men can cause stricture. If a pregnant woman has gonorrhoea, her baby may contract ophthalmia neonatorum. Later complications can include arthritis, endocarditis, and infection of the eyes, causing conjunctivitis. Treatment with sulphonamides, penicillin, or tetracycline in the early stages of the disease is usually effective.
—gonorrhoeal adj.

Back  -    New Search

Goodpasture's syndrome (guud-pas-cherz) n.

a haemorrhagic lung disorder, resulting in the coughing up of blood, associated with glomerulonephritis. [E. W. Goodpasture (1886–1960), US pathologist]

Back  -    New Search

goose flesh n.

the reaction of the skin to cold or fear. The blood vessels contract and the small muscle attached to the base of each hair follicle also contracts, causing the hairs to stand up: this gives the skin an appearance of plucked goose skin.

Back  -    New Search

Gordh needle (gord) n.

an intravenous needle with an expanded base containing a rubber diaphragm, used to administer repeated injections. [T. Gordh , Swedish anaesthetist]

Back  -    New Search

gorget (gor-jit) n.

an instrument used in the operation for removal of stones from the bladder. It is a director or guide with a wide groove.

Back  -    New Search

goserelin (gos--rel-in) n.

see LHRH ANALOGUE.

Back  -    New Search

gouge (gowj) n.

a curved chisel used in orthopaedic operations to cut and remove bone.

Back  -    New Search

gout (gowt) n.

a disease in which a defect in uric acid metabolism causes an excess of the acid and its salts (urates) to accumulate in the bloodstream and the joints respectively. It results in attacks of acute gouty arthritis and chronic destruction of the joints and deposits of urates (tophi) in the skin and cartilage, especially of the ears. Treatment with uricosuric drugs or allopurinol can control the disease; acute attacks are treated with anti-inflammatory analgesics. See also PODAGRA.

Back  -    New Search

Graafian follicle (grah-fi-n) n.

a mature follicle in the ovary prior to ovulation, containing a large fluid-filled cavity that distends the surface of the ovary. The oocyte develops inside the follicle, attached to one side. [R. de Graaf (1641–73), Dutch physician and anatomist]

Back  -    New Search

graded self-exposure (gray-did self-iks-poh-zher) n.

a technique used in the behaviour therapy of phobias. A hierarchy of fears (increasingly fearful stimuli) is set up and the patients expose themselves to each level of the hierarchy in turn. Exposure continues until habituation occurs before proceeding to the next highest level of the hierarchy. The patient is then ultimately able to cope with the feared object or situation.

Back  -    New Search

Graefe's knife (gray-fiz) n.

a knife with a narrow sharply pointed blade, used in operations for the removal of cataract. [A. von Graefe (1928–70), German ophthalmologist]

Back  -    New Search

graft (grahft)

1 n. any organ, tissue, or object used for transplantation to replace a faulty part of the body. bone g. healthy bone used to fill a defect in a bone or to stimulate fracture healing. corneal g. see KERATOPLASTY. See also SKIN (GRAFT), TRANSPLANTATION.

2 vb. to transplant an organ or tissue.
Top

Back  -    New Search

graft-versus-host disease (GVHD) n.

a condition that occurs following bone marrow transplantation and sometimes blood transfusion, in which lymphocytes from the graft attack specific tissues in the host. The skin, gut, and liver are the most severely affected. Drugs that suppress the immune reaction, such as steroids and cyclosporin A, reduce the severity of the rejection.

Back  -    New Search

grain (grayn) n.

a unit of mass equal to 1/7000 of a pound (avoirdupois). 1 grain = 0.0648 gram.

Back  -    New Search

gram (gram) n.

a unit of mass equal to one thousandth of a kilogram. Symbol: g.

Back  -    New Search

-gram suffix

denoting a record; tracing.

Back  -    New Search

gramicidin (gram-i-sy-din) n.

an antibiotic that acts against a wide range of bacteria. It is used in ointments, solutions, or sprays for the treatment of infected ulcers, wounds, and burns.

Back  -    New Search

Gram's stain (gramz) n.

a method of staining bacterial cells, used as a primary means of identification. The bacterial cells are stained with a violet dye, treated with decolorizer (e.g. alcohol), and then counterstained with red dye. Gram-negative bacteria lose the initial stain but take up the counterstain, so that they appear red microscopically. Gram-positive bacteria retain the initial stain, appearing violet microscopically. [H. C. J. Gram (1853–1938), Danish physician]

Back  -    New Search

grand mal (major epilepsy) (gron mal) n.

see EPILEPSY.

Back  -    New Search

grand multiparity (grand multi-pa-riti) n.

the condition of a woman who has had six or more previous pregnancies. Such women are more prone to the accidents of labour and to some of the diseases of pregnancy.

Back  -    New Search

granular cast (gran-yoo-ler) n.

a cellular cast derived from a kidney tubule. Such casts are shed from the kidney in certain kidney diseases, notably acute glomerulo-nephritis. Their presence in the urine indicates continued activity of the disease.

Back  -    New Search

granulation (gran-yoo-lay-shn) n.

the growth of small rounded outgrowths, made up of small blood vessels and connective tissue, on the healing surface of a wound (when the edges do not fit closely together) or an ulcer.

Back  -    New Search

granulocyte (gran-yoo-loh-syt) n.

any of a group of white blood cells that contain granules in their cytoplasm. They can be subclassified into neutrophils, eosinophils, and basophils.

Back  -    New Search

granulocytopenia (gran-yoo-loh-sy-toh-pee-ni) n.

a reduction in the number of granulocytes in the blood. See NEUTROPENIA.

Back  -    New Search

granuloma (gran-yoo-loh-m) n. (pl. granulomata or granulomas)

a mass of granulation tissue produced in response to chronic infection, inflammation, a foreign body, or to unknown causes. g. annulare a chronic skin condition, of unknown cause, in which there is a ring or rings of closely set papules, principally on the hands and arms. g. inguinale a sexually transmitted disease caused by the bacterium Calymmatobacterium granulomatis, marked by a pimply rash on and around the genital organs, which develops into a granulomatous ulcer. See also PYOGENIC (GRANULOMA).
—granulomatous adj.

Back  -    New Search

granulomatosis (gran-yoo-loh-m-toh-sis) n.

any condition marked by multiple widespread granulomata. See also WEGENER'S GRANULOMATOSIS.

Back  -    New Search

granulopoiesis (gran-yoo-loh-poi-ee-sis) n.

the process of production of granulocytes, which normally occurs in the blood-forming tissue of the bone marrow. See also HAEMOPOIESIS.

Back  -    New Search

graph- (grapho-) prefix

denoting handwriting.

Back  -    New Search

-graph suffix

denoting an instrument that records.

Back  -    New Search

grattage (grat-ahzh) n.

the process of brushing or scraping the surface of a slowly healing ulcer or wound to remove granulation tissue, which may delay healing.

Back  -    New Search

gravel (grav-l) n.

small stones formed in the urinary tract. The passage of gravel from the kidneys is usually associated with severe pain (ureteric colic) and may cause blood in the urine. See also CALCULUS.

Back  -    New Search

Graves' disease (exophthalmic goitre) (grayvz) n.

see THYROTOXICOSIS. [R. J. Graves (1797–1853), Irish physician]

Back  -    New Search

gravid (grav-id) adj.

pregnant.

Back  -    New Search

Grawitz tumour (grah-vits) n.

see HYPERNEPHROMA. [P. A. Grawitz (1850–1932), German pathologist]

Back  -    New Search

gray (gray) n.

the SI unit of absorbed dose of ionizing radiation, being the absorbed dose when the energy per unit mass imparted to matter by ionizing radiation is 1 joule per kilogram. It has replaced the rad. Symbol: Gy.

Back  -    New Search

green monkey disease n.

see MARBURG DISEASE.

Back  -    New Search

greenstick fracture (green-stik) n.

see FRACTURE.

Back  -    New Search

grey matter (gray) n.

the darker coloured tissues of the central nervous system, composed mainly of the cell bodies of neurones, branching dendrites, and glial cells. Compare WHITE MATTER.

Back  -    New Search

Griffith's types (grif-iths) pl. n.

subdivisions of Lancefield group A streptococci (see LANCEFIELD CLASSIFICATION) on the basis of their agglutination reactions. [F. Griffith (1877–1941), British bacteriologist]

Back  -    New Search

gripe (gryp) n.

severe abdominal pain (see COLIC).

Back  -    New Search

griseofulvin (griz-i-oh-ful-vin) n.

an antibiotic administered by mouth to treat fungal infections of the hair, skin, and nails, such as ringworm. Trade names: Fulcin , Grisovin .

Back  -    New Search

grocer's itch (groh-serz) n.

dermatitis of the hands caused by frequent contact with flour and sugar.

Back  -    New Search

groin (groin) n.

the external depression on the front of the body that marks the junction of the abdomen with either of the thighs. See also INGUINAL.

Back  -    New Search

ground substance (grownd) n.

see CONNECTIVE TISSUE.

Back  -    New Search

group practice (groop) n.

a partnership of two or more general practitioners who share such resources as premises and administrative and nursing staff. The premises from which they operate may be privately owned or a publicly owned health centre.

Back  -    New Search

group therapy n.

1 (group psycho-therapy) psychotherapy involving at least two patients and a therapist. The patients are encouraged to understand and analyse their own and one another's problems. See also ENCOUNTER GROUP, PSYCHODRAMA.

2 therapy in which people with the same problem, such as alcoholism, meet and discuss together their difficulties and possible ways of overcoming them.
Top

Back  -    New Search

growth factor (grohth) n.

a polypeptide that is produced by cells and stimulates them to proliferate. Some may be involved in the abnormal regulation of growth seen in cancer.

Back  -    New Search

growth hormone (GH, somatotrophin)

n. a hormone, synthesized and stored in the anterior pituitary gland, that promotes growth of the long bones in the limbs and increases protein synthesis (via somatomedin). Its release is controlled by the opposing actions of growth-hormone releasing hormone and somatostatin.

Back  -    New Search

GSI n.

genuine stress incontinence. See INCONTINENCE.

Back  -    New Search

guanethidine (gwahn-eth-i-deen) n.

a drug that is administered by mouth to reduce high blood pressure (see SYMPATHOLYTIC). Trade name: Ismelin .

Back  -    New Search

guanine (gwah-neen) n.

one of the nitrogen-containing bases (see PURINE) that occurs in the nucleic acids DNA and RNA.

Back  -    New Search

gubernaculum (gew-ber-nak-yoo-lm) n. (pl. gubernacula)

either of a pair of fibrous strands of tissue that connect the gonads to the inguinal region in the fetus.

Back  -    New Search

Guillain-Barré syndrome (postinfective polyneuropathy) (gee-yan ba-ray) n.

a disease of the peripheral nerves in which there is numbness and weakness in the limbs. It usually develops 10–20 days after a respiratory or gastrointestinal infection that provokes an allergic response in the peripheral nerves. [G. Guillain (1876–1961) and A. Barré (1880–1967), French neurologists]

Back  -    New Search

guillotine (gil--teen) n.

1 a surgical instrument used for removing the tonsils.

2 an encircling suture to control the escape of fluid or blood from an orifice or to close a gap.

Top

Back  -    New Search

guinea worm (ginn-i) n.

a parasitic nematode worm, Dracunculus medinensis. The adult female lives in the connective tissues beneath the skin and releases its larvae into a large blister on the legs or arms. See also DRACONTIASIS.

Back  -    New Search

Gulf War syndrome (gulf wor) n.

a variety of symptoms, mainly neurological (including chronic fatigue, dizziness, amnesia, digestive upsets, and muscle wasting), that have been attributed to exposure of armed forces personnel to chemicals (e.g. insecticides) used during the Gulf War (1991) or possibly to the effects of vaccines and tablets given to protect personnel against the anticipated threat of chemical and biological warfare during the conflict.

Back  -    New Search

gullet (gul-it) n.

see OESOPHAGUS.

Back  -    New Search

gum (gum) n.

(in anatomy) see GINGIVA.

Back  -    New Search

gumboil (gum-boil) n.

the opening on the surface of the gum of a sinus tract from a chronic abscess associated with the roots of a tooth. It may be accompanied by varying degrees of swelling, pain, and discharge.

Back  -    New Search

gumma (gum-) n.

a small soft tumour, characteristic of the tertiary stage of syphilis, that occurs in connective tissue, the liver, brain, testes, heart, or bone.

Back  -    New Search

gustation (gus-tay-shn) n.

the sense of taste or the act of tasting.

Back  -    New Search

gustatory (gus-t-ter-i) adj.

relating to the sense of taste or to the organs of taste.

Back  -    New Search

gut (gut) n.

1 see INTESTINE.

2 see CATGUT.
Top

Back  -    New Search

Guthrie test (guth-ri) n.

examination of a drop of blood to exclude the presence of phenylketonuria. It is performed on infants in the sixth or seventh day of life, once milk feeding has been established. [R. Guthrie (1916– ), US paediatrician]

Back  -    New Search

gutta (gut-) n. (pl. guttae)

(in pharmacy) a drop. Drops are the form in which many medicines are applied to the eyes and ears.

Back  -    New Search

gutta-percha (gut--per-ch) n.

the juice of an evergreen Malaysian tree, which is hard at room temperature but becomes soft and elastic when heated in hot water. On cooling gutta-percha will retain any deformity imparted to it when hot; it is used in dentistry.

Back  -    New Search

gutter splint (gut-er) n.

a splint formed from a casting material, moulded to conform to the shape of the limb but not encircling it, in which the limb rests as in a gutter.

Back  -    New Search

GVHD n.

see GRAFT-VERSUS-HOST DISEASE.

Back  -    New Search

gyn- (gyno-, gynaec(o)-) prefix

denoting women or the female reproductive organs.

Back  -    New Search

gynaecology (gy-ni-kol-ji) n.

the study of diseases of women and girls, particularly those affecting the female reproductive system. Compare OBSTETRICS.
—gynaecological adj.—gynaecologist n.

Back  -    New Search

gynaecomastia (gy-ni-koh-mas-ti) n.

enlargement of the breasts in the male, due either to hormone imbalance or to hormone therapy.

Back  -    New Search

gypsum (jip-sm) n.

see PLASTER OF PARIS.

Back  -    New Search

gyr- (gyro-) prefix

denoting 1 a gyrus.

2 a ring or circle.
Top

Back  -    New Search

gyrus (jy-rs) n. (pl. gyri)

a raised convolution of the cerebral cortex, between two sulci (clefts).

Back  -    New Search

H

H

symbol for hydrogen.

Back  -    New Search

habit (hab-it) n.

a constant, almost automatic, practice acquired by frequent repetition. h. training teaching psychiatric patients to relearn habits of personal hygiene by repetition and encouragement.

Back  -    New Search

habitual abortion (h-bit-yoo-l) n.

see ABORTION.

Back  -    New Search

habituation (h-bit-yoo-ay-shn) n.

1 (in psychology) a simple form of learning consisting of a gradual waning response by the subject to a continuous or repeated stimulus that is not associated with reinforcement.

2 (in pharmacology) the condition of being psychologically dependent on a drug, following repeated consumption. It is marked by reduced sensitivity to its effects and a craving for the drug if it is withdrawn. See also DEPENDENCE.
Top

Back  -    New Search

haem (heem) n.

an iron-containing compound (a porphyrin) that combines with the protein globin to form haemoglobin.

Back  -    New Search

haem- (haema-, haemo-, haemat(o)-) prefix

denoting blood.

Back  -    New Search

haemagglutination (heem--gloo-tin-ay-shn) n.

the clumping of red blood cells (see AGGLUTINATION). It is caused by an antibody-antigen reaction of some viruses and other substances.

Back  -    New Search

haemangioma (heem-an-ji-oh-m) n.

a benign tumour of blood vessels. It often appears on the skin as a type of birthmark (see NAEVUS). See also ANGIOMA.

Back  -    New Search

haemarthrosis (heem-arth-roh-sis) n.

joint pain and swelling caused by bleeding into a joint. This may follow injury or may occur spontaneously in a disease of the blood, such as haemophilia.

Back  -    New Search

haematemesis (heem--tem-i-sis) n.

the act of vomiting blood. The blood may have been swallowed but more often arises from bleeding in the oesophagus, stomach, or duodenum. Common causes are gastric and duodenal ulcers and oesophageal varices (varicose veins).

Back  -    New Search

haematin (heem--tin) n.

a chemical derivative of haemoglobin formed by removal of the protein part of the molecule and oxidation of the iron atom from the ferrous to the ferric form.

Back  -    New Search

haematinic (heem--tin-ik) n.

a drug that increases the amount of haemoglobin in the blood, e.g. ferrous sulphate and other iron-containing compounds. Haematinics are administered to prevent and treat anaemia due to iron deficiency, particularly during pregnancy.

Back  -    New Search

haematocele (heem--toh-seel) n.

a swelling caused by leakage of blood into a cavity, especially that of the membrane overlying the front and sides of the testis. parametric (pelvic) h. a swelling near the uterus formed by the escape of blood, usually from a Fallopian tube in ectopic pregnancy.

Back  -    New Search

haematocolpos (heem--toh-kol-pos) n.

the accumulation of menstrual blood in the vagina because the hymen lacks an opening. See CRYPTOMENORRHOEA.

Back  -    New Search

haematocrit (heem--toh-krit) n.

see PACKED CELL VOLUME.

Back  -    New Search

haematocyst (heem--toh-sist) n.

a cyst containing blood.

Back  -    New Search

haematogenous (haematogenic) (heem--toj-in-s) adj.

1 relating to the production of blood or its constituents.

2 produced by, originating in, or carried by the blood.
Top

Back  -    New Search

haematology (heem--tol-ji) n.

the study of blood and blood-forming tissues and the disorders associated with them.
—haematological (heem--t-loj-ik-l) adj.—haematologist n.

Back  -    New Search

haematoma (heem--toh-m) n.

an accumulation of blood within the tissues that clots to form a solid swelling. Injury, disease of the blood vessels, or a clotting disorder of the blood are the usual causative factors. extradural h. a haematoma caused by tearing of the middle meningeal artery, as a result of injury to the head. intracerebral h. a haematoma caused by bleeding into the brain resulting either from atherosclerosis of the cerebral arteries and high blood pressure or from severe head injury. subdural h. a haematoma caused by tearing of the veins where they cross the space beneath the dura. See also PERIANAL HAEMATOMA.

Back  -    New Search

haematometra (heem--toh-mee-tr) n.

1 accumulation of menstrual blood in the uterus.

2 abnormally copious bleeding in the uterus.
Top

Back  -    New Search

haematomyelia (heem--toh-my-ee-li) n.

bleeding into the tissue of the spinal cord.

Back  -    New Search

haematopoiesis (heem--toh-poi-ee-sis) n.

see HAEMOPOIESIS.

Back  -    New Search

haematoporphyrin (heem--toh-por-fi-rin) n.

a type of porphyrin produced during the metabolism of haemoglobin.

Back  -    New Search

haematosalpinx (haemosalpinx) (heem--toh-sal-pinks) n.

the accumulation of menstrual blood in the Fallopian tubes.

Back  -    New Search

haematoxylin (heem--toks-i-lin) n.

a colourless crystalline compound extracted from logwood (Haematoxylon campechianum) and used in various histological stains.

Back  -    New Search

haematozoon (heem--toh-zoh-on) n. (pl. haematozoa)

any animal parasite living in the blood.

Back  -    New Search

haematuria (heem--tewr-i) n.

the presence of blood in the urine. The blood may come from the kidneys, one or both ureters, the bladder, or the urethra, as a result of injury or disease.

Back  -    New Search

haemin (heem-in) n.

a chemical derivative of haemoglobin formed by removal of the protein part of the molecule, oxidation of the iron atom, and combination with an acid to form a salt. Compare HAEMATIN.

Back  -    New Search

haemo- prefix.

see HAEM-.

Back  -    New Search

haemochromatosis (bronze diabetes, iron-storage disease) (heem--kroh-m-toh-sis) n.

a hereditary disorder in which there is excessive absorption and storage of iron. This leads to damage of many organs, including the liver, pancreas, and endocrine glands. The main features are a bronze colour of the skin, diabetes, and liver failure. Compare HAEMOSIDEROSIS.

Back  -    New Search

haemoconcentration (hee-moh-kon-sn-tray-shn) n.

an increase in the proportion of red blood cells relative to the plasma, brought about by a decrease in the volume of plasma. Compare HAEMODILUTION.

Back  -    New Search

haemocytometer (hee-moh-sy-tom-it-er) n.

a special glass chamber of known volume into which diluted blood is introduced. The numbers of the various blood cells present are then counted visually, through a microscope.

Back  -    New Search

haemodialysis (hee-moh-dy-al-i-sis) n.

a technique of removing waste materials or poisons from the blood using the principle of dialysis. Haemodialysis is performed on patients whose kidneys have ceased to function; the process takes place in an artificial kidney , or dialyser .

Back  -    New Search

haemodilution (hee-moh-dy-lew-shn) n.

a decrease in the proportion of red blood cells relative to the plasma, brought about by an increase in the total volume of plasma. Compare HAEMOCONCENTRATION.

Back  -    New Search

haemoglobin (hee-moh-gloh-bin) n.

a substance contained within the red blood cells (erythrocytes) and responsible for their colour, composed of the pigment haem linked to the protein globin. Haemoglobin is the medium by which oxygen is transported within the body. Blood normally contains 12–18 g/dl of haemoglobin. See also MYOHAEMOGLOBIN, OXYHAEMOGLOBIN.

Back  -    New Search

haemoglobinaemia (heem--gloh-bin-ee-mi) n.

the presence of haemoglobin in the blood plasma.

Back  -    New Search

haemoglobinometer (heem--gloh-bin-om-it-er) n.

an instrument for determining the concentration of haemoglobin in a sample of blood.

Back  -    New Search

haemoglobinopathy (heem--gloh-bin-op--thi) n.

any of a group of inherited diseases, including thalassaemia and sickle-cell disease, in which there is an abnormality in the production of haemoglobin.

Back  -    New Search

haemoglobinuria (heem--gloh-bin-yoor-i) n.

the presence in the urine of free haemoglobin. The condition sometimes follows strenuous exercise. It is also associated with certain infectious diseases, ingestion of certain chemicals, and injury.

Back  -    New Search

haemogram (hee-moh-gram) n.

the results of a routine blood test, including an estimate of the blood haemoglobin level, packed cell volume, and blood count.

Back  -    New Search

haemolysin (hi-mol-i-sin) n.

see LYSIN.

Back  -    New Search

haemolysis (hi-mol-i-sis) n.

the destruction of red blood cells (erythrocytes). Within the body, haemolysis may result from poisoning, infection, or the action of antibodies; it may occur in mismatched blood transfusions. It usually leads to anaemia. See also LAKING.

Back  -    New Search

haemolytic (hee-moh-lit-ik) adj.

causing, associated with, or resulting from destruction of red blood cells (erythrocytes). h. anaemia see ANAEMIA.

Back  -    New Search

haemolytic disease of the newborn n.

the condition resulting from destruction (haemolysis) of the red blood cells of the fetus by antibodies in the mother's blood passing through the placenta. This most commonly happens when the red blood cells of the fetus are Rh positive (see RHESUS FACTOR) but the mother's red cells are Rh negative. The fetal cells are therefore incompatible in her circulation and evoke the production of antibodies. This may result in very severe anaemia of the fetus or severe jaundice after birth. A blood test early in pregnancy enables the detection of antibodies in the mother's blood and the adoption of various precautions for the infant's safety. See also ANTI D.

Back  -    New Search

haemolytic uraemic syndrome n.

a condition in which sudden rapid destruction of red blood cells (see HAEMOLYSIS) causes acute renal failure due partly to obstruction of small arteries in the kidneys. The haemolysis also causes a reduction in the number of platelets, which can lead to severe haemorrhage. The syndrome may occur as a result of septicaemia following a respiratory or gastrointestinal infection (especially by pathogenic Escherichia coli), eclamptic fits in pregnancy (see ECLAMPSIA), or as a reaction to certain drugs.

Back  -    New Search

haemopericardium (heem--pe-ri-kar-dim) n.

the presence of blood within the pericardium, which may result from injury, tumours, rupture of the heart, or a leaking aneurysm.

Back  -    New Search

haemoperitoneum (heem--pe-ri-tn-ee-m) n.

the presence of blood in the peritoneal cavity, between the lining of the abdomen or pelvis and the membrane covering the organs within.

Back  -    New Search

haemophilia (hee-moh-fil-i) n.

a hereditary disorder in which the blood clots very slowly, due to a deficiency of either of two coagulation factors: Factor VIII (anti-haemophilic factor) or Factor IX (Christmas factor). Prolonged bleeding follows any injury or wound, and in severe cases there is spontaneous bleeding into muscles and joints. Bleeding in haemophilia may be treated by transfusions of plasma or administration of concentrated Factor VIII or Factor IX. Haemophilia is almost exclusively restricted to males: women can carry the disease without being affected themselves.
—haemophiliac n. —haemophilic adj.

Back  -    New Search

Haemophilus (hi-mof-i-ls) n.

a genus of Gram-negative aerobic nonmotile parasitic rodlike bacteria frequently found in the respiratory tract. Most species are pathogenic. H. influenzae a species associated with acute and chronic respiratory infections: a common secondary cause of influenza infections and a primary cause of bacterial meningitis.

Back  -    New Search

haemophthalmia (heem-off-thal-mi) n.

bleeding into the vitreous humour of the eye: vitreous haemorrhage.

Back  -    New Search

haemopneumothorax (heem--new-moh-thor-aks) n.

the presence of blood and air in the pleural cavity, usually as a result of injury. See also HAEMOTHORAX.

Back  -    New Search

haemopoiesis (hee-moh-poi-ee-sis) n.

the process of production of blood cells and platelets which continues throughout life, replacing aged cells (which are removed from the circulation). In healthy adults, haemopoiesis is confined to the bone marrow. See also ERYTHROPOIESIS, LEUCOPOIESIS, THROMBOPOIESIS.
—haemopoietic adj.

Back  -    New Search

haemopoietin (hee-moh-poi-ee-tin) n.

see ERYTHROPOIETIN.

Back  -    New Search

haemoptysis (hi-mop-ti-sis) n.

the coughing up of blood.

Back  -    New Search

haemorrhage (bleeding) (hem-er-ij) n.

the escape of blood from a ruptured blood vessel, externally or internally. Arterial blood is bright red and emerges in spurts, venous blood is dark red and flows steadily, while damage to minor vessels may produce only an oozing. Rupture of a major blood vessel such as the femoral artery can lead to the loss of several litres of blood in a few minutes, resulting in shock, collapse, and death, if untreated. primary h. haemorrhage occurring immediately after injury or surgery. secondary h. haemorrhage occurring some time after injury, usually due to sepsis. See also HAEMATEMESIS, HAEMATURIA, HAEMOPTYSIS, SPLINTER HAEMORRHAGE.

Back  -    New Search

haemorrhagic (hem-er-aj-ik) adj.

associated with or resulting from blood loss. See HAEMORRHAGE.

Back  -    New Search

haemorrhagic disease of the newborn n.

a transient disorder of newborn infants in which prolonged bleeding may result from the slightest injury. It is caused by deficiency of vitamin K and therefore of prothrombin, which is necessary for blood clotting.

Back  -    New Search

haemorrhoidectomy (hem-er-oid-ek-tmi) n.

the surgical operation for removing haemorrhoids, which are tied and then excised. The operation is usually performed only for second- or third-degree haemorrhoids.

Back  -    New Search

haemorrhoids (piles) (hem-er-oidz) pl. n.

enlargement of the normal spongy blood-filled cushions in the wall of the anus (internal h. ), usually a consequence of prolonged constipation or, occasionally, diarrhoea. The main symptom is bleeding. external h. prolapsed internal haemorrhoids or perianal haematomas. first-degree h. haemorrhoids that never appear at the anus but cause bleeding at the end of defecation. second-degree h. haemorrhoids that protrude beyond the anus as an uncomfortable swelling but return spontaneously. third-degree h. haemorrhoids that remain outside the anus and need to be returned by pressure. They often require surgery (see HAEMORRHOIDECTOMY), especially if they become strangulated (producing severe pain and further enlargement).

Back  -    New Search

haemosalpinx (hee-moh-sal-pinks) n.

see HAEMATOSALPINX.

Back  -    New Search

haemosiderosis (heem--sid-er-oh-sis) n.

a disorder caused by excessive deposition of iron, which results from excessive intake or administration of iron. It results in damage to various organs, including the heart and liver. Compare HAEMOCHROMATOSIS.

Back  -    New Search

haemostasis (hee-moh-stay-sis) n.

the arrest of bleeding, involving the physiological processes of blood coagulation and the contraction of damaged blood vessels. The term is also applied to various surgical procedures used to stop bleeding.

Back  -    New Search

haemostatic (styptic) (hee-moh-stat-ik) n.

an agent that stops or prevents haemorrhage; for example, phytomenadione and thromboplastin.

Back  -    New Search

haemothorax (hee-moh-thor-aks) n.

blood in the pleural cavity, usually due to injury.

Back  -    New Search

hair (hair) n.

a threadlike keratinized outgrowth of the epidermis of the skin. The root of the hair, beneath the surface of the skin, is expanded at its base to form the bulb, which contains a matrix of dividing cells. As new cells are formed the older ones are pushed upwards and become keratinized to form the root and shaft. h. follicle a sheath of epidermal cells and connective tissue that surrounds the root of a hair. h. papilla a projection of the dermis that is surrounded by the base of the hair bulb. It contains the capillaries that supply blood to the growing hair.

Back  -    New Search

hairball (hair-bawl) n.

see TRICHOBEZOAR.

Back  -    New Search

hairy cell (hair-i) n.

an abnormal white blood cell that has the appearance of an immature lymphocyte with fine hairlike cytoplasmic projections around the perimeter of the cell. It is found in a rare form of leukaemia (h.-c. leukaemia ) most commonly occurring in young men.

Back  -    New Search

half-life (hahf-lyf) n.

1 the time taken for half the atoms of a radioactive isotope to decay: a measure of the radioactivity of the isotope.

2 (in pharmacology) the time taken for the body to excrete half a given amount of a drug.
Top

Back  -    New Search

halibut liver oil (hal-i-bt) n.

an oil extracted from the liver of halibut. It is rich in vitamins A and D.

Back  -    New Search

halitosis (hal-i-toh-sis) n.

bad breath. Causes of temporary halitosis include recently eaten strongly flavoured food; other causes include mouth breathing, periodontal disease, and infective conditions of the nose, throat, and lungs.

Back  -    New Search

hallucination (h-loo-sin-ay-shn) n.

a false perception of something that is not really there. Hallucinations may be provoked by psychological illness (such as schizophrenia) or physical disorders in the brain or they may be caused by drugs or sensory deprivation. Compare ILLUSION.

Back  -    New Search

hallucinogen (h-loo-sin--jen) n.

a drug that produces hallucinations, e.g. cannabis and lysergic acid diethylamide. Hallucinogens were formerly used to treat certain types of mental illness.
—hallucinogenic adj.

Back  -    New Search

hallux (hal-ks) n. (pl. halluces)

the big toe. h. rigidus painful stiffness of the joint between the big toe and the first metatarsal bone, usually resulting from osteoarthritis. h. valgus a deformity in which the big toe is displaced towards the other toes. It is usually associated with a bunion. h. varus displacement of the big toe away from the others.

Back  -    New Search

halogen (hal--jen) n.

any one of the related elements fluorine, chlorine, bromine, or iodine.

Back  -    New Search

haloperidol (hal-oh-pe-ri-dol) n.

a butyrophenone antipsychotic drug that is administered by mouth or injection to relieve anxiety and tension in the treatment of schizophrenia and other psychiatric disorders. Trade names: Haldol , Serenace .

Back  -    New Search

halothane (hal-oh-thayn) n.

a potent general anaesthetic administered by inhalation. It is used for inducing and maintaining anaesthesia in all types of surgical operations. Trade name: Fluothane .

Back  -    New Search

hamate bone (unciform bone) (ham-ayt) n.

a hook-shaped bone of the wrist (see CARPUS). It articulates with the capitate and triquetral bones at the sides, with the lunate bone behind, and with the fourth and fifth metacarpal bones in front.

Back  -    New Search

hammer (ham-er) n.

(in anatomy) see MALLEUS.

Back  -    New Search

hammer toe n.

a deformity of a toe, most often the second, caused by fixed flexion of the first joint. A corn often forms over the deformity, which may be painful.

Back  -    New Search

hamstring (ham-string) n.

any of the tendons at the back of the knee. h. muscles the biceps femoris, semitendinosus, and semimembranosus, attached by the hamstrings to their insertions in the tibia and fibula.

Back  -    New Search

hand (hand) n.

the terminal organ of the upper limb. It comprises the eight bones of the carpus, the five metacarpal bones, and the phalangeal bones plus the surrounding tissues.

Back  -    New Search

handedness (han-did-nis) n.

the preferential use of one hand, rather than the other, in voluntary actions. In right-handedness this correlates with the half of the brain that is dominant for speech: some 97% of right-handed people have left-hemisphere dominance for speech, while only 60% of left-handed people are right-hemisphere dominant for speech.

Back  -    New Search

hand, foot, and mouth disease n.

a self-limiting disease, mainly affecting young children, caused by Coxsackie virus A16. A feeling of mild illness is accompanied by mouth ulcers and painful blisters on the hands and feet.

Back  -    New Search

handicap (han-di-kap) n.

1 partial or total inability to perform a social, occupational, or other activity that the affected person wants to do.

2 see MENTAL HANDICAP.
Top

Back  -    New Search

Hand-Schüller-Christian disease (hand shew-ler kris-chn) n.

see RETICULOENDOTHELIOSIS. [A. Hand (1868–1949), US paediatrician; A. Schüller (1874–1958), Austrian neurologist; H. A. Christian (1876–1951), US physician]

Back  -    New Search

Hansen's bacillus (han-snz) n.

see MYCOBACTERIUM. [A. G. H. Hansen (1841–1912), Norwegian bacteriologist]

Back  -    New Search

Hansen's disease n.

see LEPROSY.

Back  -    New Search

hantavirus (han-t-vy-rs) n.

a virus that infects rats, mice, and voles and causes disease in humans when the secretions or excreta of these rodents are inhaled or ingested. The symptoms, which vary according to the strain of the infecting virus, range from those of a mild influenza-like illness to serious kidney or lung damage.

Back  -    New Search

haploid (monoploid) (hap-loid) adj.

describing cells, nuclei, or organisms with a single set of unpaired chromosomes. In man the gametes are haploid following meiosis. Compare DIPLOID, TRIPLOID.
—haploid n.

Back  -    New Search

hapt- (hapto-) prefix

denoting touch.

Back  -    New Search

hapten (hap-tn) n.

a substance that becomes antigenic by combining with and modifying the body's own proteins.

Back  -    New Search

harelip (hair-lip) n.

see CLEFT LIP.

Back  -    New Search

Harrison's sulcus (ha-ri-snz) n.

a depression on both sides of the chest wall of a child between the pectoral muscles and the lower margin of the ribcage. It develops in conditions in which the airways are partially obstructed or when the lungs are abnormally congested due to some congenital abnormality of the heart. [E. Harrison (1789–1838), British physician]

Back  -    New Search

Harris's operation (ha-ris-z) n.

an operation in which the prostate gland is removed through an incision above the pubic bone and through the bladder. See PROSTATECTOMY. [S. H. Harris (1880–1936), Australian surgeon]

Back  -    New Search

Hartmann's pouch (hart-manz) n.

a saclike dilatation of the gall-bladder wall near its outlet; it is a common site for finding gallstones. [H. Hartmann (1860–1952), French surgeon]

Back  -    New Search

Hartmann's solution n.

a solution containing sodium, potassium, and calcium chlorides and sodium lactate, administered by infusion to treat dehydration. [A. Hartmann (1898–1964), US physician]

Back  -    New Search

Hartnup disease (hart-nup) n.

a rare hereditary defect in the absorption of the amino acid tryptophan, leading to mental retardation, thickening and roughening of the skin on exposure to light, and lack of muscular coordination. The condition is similar to pellagra. Treatment with nicotinamide is usually effective. [Hartnup family, in whom it was first reported]

Back  -    New Search

Hashimoto's disease (hash-i-moh-tohz) n.

chronic thyroiditis due to the formation of autoantibodies against normal thyroid tissue. Its features include a firm swelling of the thyroid and partial or total failure of secretion of thyroid hormones; often there are autoantibodies to other organs, such as the stomach. Women are more often affected than men and the condition often occurs in families. [H. Hashimoto (1881–1934), Japanese surgeon]

Back  -    New Search

hashish (hash-eesh) n.

see CANNABIS.

Back  -    New Search

haustrum (how-strum) n.

one of the pouches on the external surface of the colon.

Back  -    New Search

Haversian canal (ha-ver-si-n) n.

any one of the small canals that ramify throughout compact bone. See also BONE. [C. Havers (1650–1702), English anatomist]

Back  -    New Search

Haversian system n.

see BONE.

Back  -    New Search

hay fever (hay) n.

a form of allergy due to pollen, characterized by inflammation of the membrane lining the nose and sometimes of the conjunctiva (vernal or allergic conjunctivitis ). The symptoms of sneezing, running or blocked nose, and watering eyes often respond to treatment with antihistamines. Medical name: allergic rhinitis .

Back  -    New Search

HCG n.

see HUMAN CHORIONIC GONADOTROPHIN.

Back  -    New Search

head (hed) n.

1 the part of the body that contains the brain and the organs of sight, hearing, smell, and taste.

2 the rounded portion of a bone, which fits into a groove of another to form a joint.
Top

Back  -    New Search

headache (hed-ayk) n.

pain felt deep within the skull. Most headaches are caused by emotional stress or fatigue but some are symptoms of serious intracranial disease. See also MIGRAINE.

Back  -    New Search

head injury (in-jeri) n.

an injury usually resulting from a blow to the head and often associated with brain injury. It may result in contusion or - if the blood vessels in the head are torn - a haematoma. The level of consciousness of a patient following a head injury can be assessed using the Glasgow scoring system.

Back  -    New Search

Heaf test (heef) n.

a skin test to determine whether or not an individual is immune to tuberculosis. A spring-loaded gun mounted with very short needles produces a circle of six punctures in the forearm through which tuberculin is introduced. If the test is positive a reaction causes the skin to become red and raised, indicating that the individual is immune. [F. R. G. Heaf (1895–1973), British physician]

Back  -    New Search

healing (heel-ing) n.

see INTENTION.

Back  -    New Search

Health and Safety Executive (HSE) (helth) n.

(in Britain) a statutory body responsible for the health and safety of workers (including factory, office, and agricultural workers).

Back  -    New Search

Health Authority n.

a body through which the National Health Service is administered at district level. Health Authorities were formed in 1996 by the merger of the District Health Authorities and the Family Health Service Authorities.

Back  -    New Search

health care n.

see PRIMARY HEALTH CARE, SECONDARY HEALTH CARE, TERTIARY HEALTH CARE.

Back  -    New Search

health-care assistant n.

a support worker in a clinical area who works under the supervision of a registered practitioner who is accountable for the support worker's standards and activities. A health-care assistant may be registered at level 1 or 2 of the National Council for Vocational Qualifications (NCVQ), having completed a recognized course. See also NCVQ, SUPPORT WORKER.

Back  -    New Search

health-care delivery n.

the services provided by nurses and others in the health service.

Back  -    New Search

health centre n.

(in Britain) a building, owned or leased by a community trust or a Health Authority, that houses personnel and/or services from one or several sections of the National Health Service.

Back  -    New Search

health education n.

persuasive methods used to encourage people to adopt lifestyles that the educators believe will improve health and to reject habits regarded as harmful to health.

Back  -    New Search

health promotion n.

a programme of surveillance planned on a community basis to maintain the best possible health and quality of life of the members of that community. Programmes include health education, immunization, and screening tests.

Back  -    New Search

Health Service Commissioner (Health Service Ombudsman) n.

an official, responsible to Parliament, who is appointed to protect the interests of patients in relation to administration of and provision of health care by the National Health Service. He can investigate complaints and allegations of maladministration by a Health Authority or trust and complaints involving the clinical judgment of medical practitioners.

Back  -    New Search

health service manager n.

an administrator with special training and skills in management who is concerned with running hospitals and other health services. Generally, the basic training for managers is in disciplines other than health; however, doctors, nurses, and others may fill such posts, sometimes combining them with professional appointments.

Back  -    New Search

health service planning n.

balancing the needs of a community, assessed by such indices as mortality, morbidity, and disability, with the resources available to meet these needs in terms of medical manpower (ensuring the numbers in training grades meet but do not exceed future requirements for career grades) and technical resources, such as hospitals (capital planning), equipment, and medicines.

Back  -    New Search

health visitor (public health nurse) n.

(in Britain) a trained nurse with specialist qualifications in health promotion and public health. Most of the work of health visitors is focused on families with children but can be extended to other targeted groups (e.g. the elderly).

Back  -    New Search

hearing aid (heer-ing) n.

an electronic device to enable a deaf person to hear, consisting of a miniature sound receiver, an amplifier, and either an earpiece or a vibrator to transfer the amplified sound to the ear. bone-anchored h. a. (BAHA) a hearing aid for those with certain forms of conductive deafness in which the vibrator is a small titanium screw fixed into the bone of the skull behind the external ear.

Back  -    New Search

heart (hart) n.

a hollow muscular cone-shaped organ, lying between the lungs, with the apex directed downwards, forwards, and to the left. It is divided by a septum into separate right and left halves, each of which is divided into an upper atrium and a lower ventricle (see illustration). Deoxygenated blood is pumped to the lungs via the right atrium and ventricle; newly oxygenated blood is pumped out to the body via the left atrium and ventricle. The direction of blood flow within the heart is controlled by valves.

Back  -    New Search

heart attack n.

see MYOCARDIAL INFARCTION.

Back  -    New Search

heart block n.

a condition in which conduction of the electrical impulses generated by the sinoatrial node is impaired, so that the pumping action of the heart is slowed down. Heart block may be congenital or it may be due to heart disease, myocarditis, cardiomyopathy, and disease of the valves. Symptoms may be abolished by the use of an artificial pacemaker. first degree h. b. heart block in which conduction between atria and ventricles is delayed. second degree h. b. heart block in which not all the impulses are conducted from the atria to the ventricles. third degree h. b. heart block in which no impulses are conducted and the ventricles beat at their own slow intrinsic rate (20–40 per minute).

Back  -    New Search

heartburn (pyrosis) (hart-bern) n.

discomfort or pain, usually burning in character, that is felt behind the breastbone. It may be accompanied by the appearance of acid or bitter fluid in the mouth and is usually caused by regurgitation of stomach contents into the gullet or by oesophagitis.

Back  -    New Search

heart failure n.

a condition in which the pumping action of the ventricle of the heart is inadequate. This results in back pressure of blood, with congestion of the lungs and liver, and oedema. There is a reduced flow of arterial blood from the heart, which in extreme cases results in peripheral circulatory failure (cardiogenic shock). Heart failure may result from any condition that overloads, damages, or reduces the efficiency of the heart muscle, such as coronary thrombosis or hypertension. Treatment consists of rest, a low salt diet, diuretic drugs (e.g. frusemide), and digitalis derivatives (e.g. digoxin).

Back  -    New Search

heart-lung machine n.

an apparatus for taking over temporarily the functions of both the heart and the lungs during heart surgery. It incorporates a pump, to maintain the circulation, and equipment to oxygenate the blood.

Back  -    New Search

heater-probe (heet-er-prohb) n.

a device that can be passed through an endoscope to apply controlled heat in order to coagulate a bleeding peptic ulcer.

Back  -    New Search

heat exhaustion (heet) n.

fatigue and collapse due to the low blood pressure and blood volume that result from loss of body fluids and salts after prolonged or unaccustomed exposure to heat.

Back  -    New Search

heatstroke (sunstroke) (heet-strohk) n.

raised body temperature (pyrexia), absence of sweating, and eventual loss of consciousness due to failure or exhaustion of the temperature-regulating mechanism of the body.

Back  -    New Search

hebephrenia (hee-bi-free-ni) n.

a form of schizophrenia. It is typically a chronic condition, and the most prominent features are disordered thinking; inappropriate emotions with thoughtless cheerfulness, apathy, or querulousness; and silly behaviour. It typically starts in adolescence or young adulthood.
—hebephrenic adj.

Back  -    New Search

Heberden's node (hee-ber-dnz) n.

a bony thickening arising at the terminal joint of a finger in osteoarthritis. It is often inherited. [W. Heberden (1710–1801), British physician]

Back  -    New Search

hebetude (heb-i-tewd) n.

apathy and emotional dullness. This is not a symptom specific to any one condition; extreme degrees are found in schizophrenia and dementia.

Back  -    New Search

hectic (hek-tik) adj.

occurring regularly. h. fever a fever that typically develops in the afternoons, in cases of pulmonary tuberculosis.

Back  -    New Search

hecto- prefix

denoting a hundred.

Back  -    New Search

heel (heel) n.

the part of the foot that extends behind the ankle joint. See CALCANEUS.

Back  -    New Search

Hegar's sign (hay-garz) n.

an indication of pregnancy detectable between the 6th and 12th weeks: used before modern urine tests for pregnancy were available. If the fingers of one hand are inserted into the vagina and those of the other are placed over the pelvic cavity, the lower part of the uterus feels very soft compared with the body of the uterus above and the cervix below. [A. Hegar (1830–1914), German gynaecologist]

Back  -    New Search

Heimlich manoeuvre (hym-lik) n.

a technique for dislodging foreign matter from the trachea (windpipe) of someone who is choking. From behind, a person wraps his arms around the victim, places a clenched fist against the victim's abdomen (between the navel and the ribcage), grasps the fist with his other hand, and gives a quick upward thrust (which may have to be repeated) to clear the obstruction. [H. J. Heimlich (1920– ), US physician]

Back  -    New Search

helc- (helco-) prefix

denoting an ulcer.

Back  -    New Search

Helicobacter (hel-i-koh-bak-ter) n.

a genus of spiral and flagellated Gram-negative bacteria. H. pylori (formerly Campylobacter pylori) a species that occurs in the stomach and causes progressive gastritis. It is nearly always present in duodenal ulceration and usually in gastric ulceration, and has been implicated in lymphomas of the stomach. It can be eradicated using various combinations of bismuth, antibiotics, and antisecretory drugs.

Back  -    New Search

helicopter-based emergency medical services (hel-i-kopt-er-bayst i-merj-n-si) pl. n.

see HEMS.

Back  -    New Search

helio- prefix

denoting the sun.

Back  -    New Search

heliotherapy (hee-li-oh-th'e-r-pi) n.

the use of sunlight to promote healing; sunbathing.

Back  -    New Search

helium (hee-li-m) n.

a colourless inert gas that is used in combination with oxygen in respiratory tests and therapy and to prevent decompression sickness in deep-sea divers. Symbol: He.

Back  -    New Search

helix (hee-liks) n.

the outer curved fleshy ridge of the pinna of the outer ear.

Back  -    New Search

Heller's operation (hel-erz) n.

see CARDIOMYOTOMY. [E. Heller (1877–1964), German surgeon]

Back  -    New Search

Heller's test n.

a test for the presence of protein (albumin) in the urine. [J. F. Heller (1813–71), Austrian pathologist]

Back  -    New Search

HELLP syndrome (help) n.

a form of severe pre-eclampsia affecting many body systems and characterized by haemolysis, elevated liver enzymes, and a low platelet count (hence the name). It constitutes an emergency requiring prompt termination of the pregnancy.

Back  -    New Search

helminth (hel-minth) n.

any of the parasitic worms, including the flukes, tapeworms, and nematodes.

Back  -    New Search

helminthiasis (hel-min-th'y--sis) n.

the diseased condition resulting from an infestation with parasitic worms (helminths).

Back  -    New Search

helminthology (hel-min-thol-ji) n.

the study of parasitic worms.

Back  -    New Search

helper T-cell (help-er) n.

see T-CELL.

Back  -    New Search

hemeralopia (hem-er--loh-pi) n.

see DAY BLINDNESS.

Back  -    New Search

hemi- prefix

denoting (in medicine) the right or left half of the body.

Back  -    New Search

hemianopia (hemi-an-oh-pi) n.

absence of half of the normal field of vision.

Back  -    New Search

homonymous h.

hemianopia in which the same half of the visual field (right or left) is lost in both eyes.

Back  -    New Search

hemiarthroplasty (hemi-arth-roh-plasti) n.

replacement of the end of a bone on one side of a joint with a prosthesis (see ARTHROPLASTY). It is the treatment for some fractures of the hip and shoulder.

Back  -    New Search

hemiballismus (hemi-bal-iz-ms) n.

a violent involuntary movement usually restricted to one arm and primarily involving the proximal muscles. It is a symptom of disease of the basal ganglia.

Back  -    New Search

hemicolectomy (hemi-koh-lek-tmi) n.

surgical removal of about half the colon, usually the right section (right h. ) with subsequent joining of the ileum to the transverse colon. This is performed for such diseases as Crohn's disease or cancer.

Back  -    New Search

hemicrania (hemi-kray-ni) n.

1 a headache affecting only one side of the head, usually migraine.

2 absence of half of the skull in a developing fetus.
Top

Back  -    New Search

hemimelia (hemi-mee-li) n.

congenital absence or gross shortening (aplasia) of the distal portion of the arms or legs. See also ECTROMELIA.

Back  -    New Search

hemiparesis (hemi-p-ree-sis) n.

see HEMIPLEGIA.

Back  -    New Search

hemiplegia (hemiparesis) (hemi-plee-ji) n.

paralysis of one side of the body. Movements of the face and arm are often more severely affected than those of the leg. It is caused by disease of the opposite (contralateral) hemisphere of the brain.

Back  -    New Search

hemisphere (hem-iss-feer) n.

one of the two halves of the cerebrum, not in fact hemispherical but more nearly quarter-spherical.

Back  -    New Search

hemlock (hem-lok) n.

the plant Conium maculatum, found in Britain and central Europe. It is a source of the poisonous alkaloid coniine.

Back  -    New Search

hemp (hemp) n.

see CANNABIS.

Back  -    New Search

HEMS pl. n.

helicopter-based emergency medical services: a fast method for the provision of first aid and the rapid transport of the seriously injured (primary use) or the critically ill (secondary use) to a hospital.

Back  -    New Search

Henderson's model (hen-der-snz) n.

a model for nursing that describes 14 components of basic nursing that define the unique function of the nurse, which is to act in the best interests of the patient when the patient lacks the ability to do so. See also NURSING MODELS. [V. Henderson (20th century), US nurse theorist]

Back  -    New Search

Henle's loop (hen-liz) n.

the part of a kidney tubule that forms a loop extending towards the centre of the kidney. It is surrounded by blood capillaries, which absorb water and selected soluble substances back into the bloodstream. [F. G. J. Henle (1809–85), German anatomist]

Back  -    New Search

Henoch-Schönlein purpura (Schönlein-Henoch purpura, anaphylactoid purpura) (hen-ohk shern-lyn) n.

a common and frequently recurrent form of purpura found especially (but not exclusively) in young children. It is characterized by red weals and a purple rash on the buttocks and lower legs due to bleeding into the skin from inflamed capillaries, together with arthritis, gastro-intestinal symptoms, and (in some cases) nephritis. [E. H. Henoch (1820–1910), German paediatrician; J. L. Schönlein (1793–1864), German physician]

Back  -    New Search

hepar (hee-par) n.

the liver.

Back  -    New Search

heparin (hep-er-in) n.

an anticoagulant produced in liver cells, some white blood cells, and certain other sites, which acts by inhibiting the action of the enzyme thrombin in the final stage of blood coagulation. An extracted purified form of heparin is widely used for the prevention of blood coagulation both in patients with thrombosis and similar conditions and in blood collected for examination. low-molecular-weight h. a type of heparin used to prevent deep-vein thrombosis following surgery or during kidney dialysis. It is more readily absorbed and produces less risk of bleeding than standard preparations.

Back  -    New Search

hepat- (hepato-) prefix

denoting the liver.

Back  -    New Search

hepatalgia (hep--tal-ji) n.

pain in or over the liver. It is caused by liver inflammation or swelling.

Back  -    New Search

hepatectomy (hep--tek-tmi) n.

the operation of removing the liver. partial h. the removal of one or more lobes of the liver; it may be carried out after severe injury or to remove a tumour localized in one part of the liver.

Back  -    New Search

hepatic (hip-at-ik) adj.

relating to the liver. h. duct see BILE DUCT. h. encephalopathy (portosystemic encephalopathy) a condition in which brain function is impaired by the presence of toxic substances, absorbed from the colon, which are normally removed or detoxified by the liver. h. flexure the bend in the colon, just underneath the liver, where the ascending colon joins the transverse colon. h. vein one of several veins that drain blood from the liver directly into the inferior vena cava.

Back  -    New Search

hepaticostomy (hip-at-i-kost-mi) n.

a surgical operation in which a temporary or permanent opening is made into the main duct carrying bile from the liver.

Back  -    New Search

hepatitis (hep--ty-tis) n.

inflammation of the liver caused by viruses, toxic substances, or immunological abnormalities. chronic h. hepatitis that continues for months or years, eventually leading to cirrhosis, caused by persistent infection with a hepatitis virus or by autoimmune disease. h. A (epidemic h. ) infectious hepatitis transmitted by contaminated food or drink. After an incubation period of 15–40 days, the patient develops fever and sickness. Yellow discoloration of the skin (see JAUNDICE) appears about a week later and persists for up to three weeks. h. B (formerly serum h. ) infectious hepatitis transmitted by infected blood or blood products contaminated hypodermic needles, blood transfusions, etc., by sexual contact, or by contact with other body fluids. Symptoms, which develop suddenly after an incubation period of 1–6 months, include headache, fever, chills, general weakness, and jaundice. h. C (formerly non-A , non-B h. ) infectious hepatitis that has a mode of transmission similar to that of hepatitis B. h. D infectious hepatitis that occurs only with or after infection with hepatitis B and is associated with severe chronic hepatitis. h. E acute hepatitis caused by a virus transmitted by food or drink. infectious h. hepatitis caused by viruses, several types of which have been isolated as specific causes of the disease and can be detected by blood tests.

Back  -    New Search

hepatization (hep--ty-zay-shn) n.

the conversion of lung tissue, which normally holds air, into a solid liver-like mass during the course of acute lobar pneumonia.

Back  -    New Search

hepato- prefix.

see HEPAT-.

Back  -    New Search

hepatoblastoma (hep--toh-blas-toh-m) n.

a malignant tumour of the liver occurring in children, made up of embryonic liver cells.

Back  -    New Search

hepatocele (hip-at-oh-seel) n.

a hernia of the liver.

Back  -    New Search

hepatocellular (hep--toh-sel-yoo-ler) adj.

relating to or affecting the cells of the liver.

Back  -    New Search

hepatocirrhosis (hep--toh-si-roh-sis) n.

cirrhosis of the liver. See CIRRHOSIS.

Back  -    New Search

hepatocyte (hip-at-oh-syt) n.

the principal cell type in the liver: a large cell with many metabolic functions, including synthesis, storage, detoxification, and bile production.

Back  -    New Search

hepatoma (hep--toh-m) n.

a malignant tumour of the liver, originating in mature liver cells. In Western countries it often develops in patients with cirrhosis, particularly after hepatitis B or C infection. The term hepatoma is often, though incorrectly, used to include malignant tumours arising in the bile duct (see CHOLANGIOCARCINOMA).

Back  -    New Search

hepatomegaly (hep--toh-meg--li) n.

enlargement of the liver to such an extent that it can be felt below the rib margin. This may be due to congestion, inflammation, infiltration (e.g. by fat), or tumour.

Back  -    New Search

hepatotoxic (hep--toh-toks-ik) adj.

damaging or destroying liver cells. Drugs such as paracetamol can be hepatotoxic at high doses or with prolonged use.

Back  -    New Search

hept- (hepta-) prefix

denoting seven.

Back  -    New Search

hereditary (hi-red-it-er-i) adj.

transmitted from parents to their offspring; inherited.

Back  -    New Search

heredity (hi-red-iti) n.

the process that causes the biological similarity between parents and their offspring. Genetics is the study of heredity.

Back  -    New Search

heredo- prefix

denoting heredity.

Back  -    New Search

Hering-Breuer reflexes (h'e-ring broi-er) pl. n.

the reflexes that maintain the normal rhythm of inflation and deflation of the lungs. [K. E. K. Hering (1834–1918), German physiologist; J. Breuer (1842–1925), German physician]

Back  -    New Search

hermaphrodite (her-maf-r-dyt) n.

an individual in which both male and female sex organs are present or in which the sex organs contain both ovarian and testicular cells.
—hermaphroditism n.

Back  -    New Search

hernia (her-ni) n.

the protrusion of an organ or tissue out of the body cavity in which it normally lies. diaphragmatic h. the protrusion of an abdominal organ through the diaphragm into the chest cavity. femoral h. the protrusion of part of the bowel at the top of the thigh, through the point at which the femoral artery passes from the abdomen to the thigh. hiatus h. the most common type of diaphragmatic hernia, in which the stomach passes partly or completely into the chest cavity through the oesophageal opening. This hernia may be associated with gastro-oesophageal reflux. incarcerated h. a hernia that is swollen and fixed within its sac. inguinal h. (or rupture ) the protrusion of a sac of peritoneum, containing fat or part of the bowel, through the lower abdominal wall. irreducible h. a hernia that cannot be returned to its normal site. strangulated h. a hernia that is cut off from its blood supply, becoming painful and eventually gangrenous. umbilical h. (exomphalos) the protrusion of abdominal organs into the umbilical cord, due to a fault in embryonic development.

Back  -    New Search

hernio- prefix

denoting a hernia.

Back  -    New Search

hernioplasty (her-ni-oh-plasti) n.

the surgical operation to repair a hernia, in which the abnormal opening is sewn up and/or the weakness strengthened with suture material.

Back  -    New Search

herniorrhaphy (her-ni-o-r-fi) n.

surgical repair of a hernia, which can be performed through a laparoscope.

Back  -    New Search

herniotomy (her-ni-ot-mi) n.

an operation to repair a hernia that involves cutting the sac that contains it.

Back  -    New Search

heroin (h'e-roh-in) n.

a white crystalline powder derived from morphine but with a shorter duration of action. Like morphine it is a powerful narcotic analgesic whose abuse leads to dependence. See also DIAMORPHINE.

Back  -    New Search

herpangina (herp-an-jy-n) n.

an acute viral infection, predominantly affecting children, that causes fever of sudden onset associated with acute ulceration of the soft palate and tonsillar area. It usually lasts 2–5 days.

Back  -    New Search

herpes (her-peez) n.

inflammation of the skin or mucous membranes caused by herpesviruses and characterized by collections of small blisters. Treatment is with acyclovir. genital h. a sexually transmitted disease, usually caused by herpes simplex virus (HSV) type II, that is characterized by painful blisters in the genital region. It may be recurrent and is extremely contagious as the blisters burst to release viruses that infect the sexual partner. h. simplex (cold sore ) herpes that affects the lips or surrounding area, caused by HSV type I. h. zoster (shingles) herpes caused by the varicella-zoster virus, which also causes chickenpox. Following an attack of chickenpox, the virus lies dormant in the spinal cord and later migrates down a sensory nerve to affect the skin in a band. One side of the face or an eye (ophthalmic zoster ) may be involved. Shingles may be chronically painful, especially in the elderly.

Back  -    New Search

herpesvirus (her-peez-vy-rs) n.

one of a group of DNA-containing viruses causing latent infections in man and animals. The herpesviruses are the causative agents of herpes and chickenpox. See also CYTOMEGALOVIRUS, EPSTEIN-BARR VIRUS.

Back  -    New Search

Herxheimer reaction n.

see JARISCH-HERXHEIMER REACTION.

Back  -    New Search

heter- (hetero-) prefix

denoting difference; dissimilarity.

Back  -    New Search

heterochromia (het-er-oh-kroh-mi) n.

colour difference in the iris of the eye, which is usually congenital but is occasionally secondary to inflammation of the iris.
—heterochromic adj.

Back  -    New Search

heterogeneous (het-er-oh-jee-ni-s) adj.

having different properties or constituents.
—heterogeneity (het-er-oh-jin-ay-iti) n.

Back  -    New Search

heterogenous (het-er-oj-in-s) adj.

derived from a different source.

Back  -    New Search

heterograft (xenograft) (het-er-oh-grahft) n.

a living tissue graft that is made from an animal of one species to another of a different species.

Back  -    New Search

heterologous (het-er-ol--gs) adj.

derived from a different species: describing tissue used for grafting, etc.

Back  -    New Search

heterophoria (het-er-oh-for-i) n.

a tendency to squint. Under normal circumstances both the eyes work together, but if one eye is covered it will move out of alignment with the object the other eye is still viewing. When the cover is removed the eye immediately returns to its normal position. See also STRABISMUS.

Back  -    New Search

heterophyiasis (het-er-oh-fi-I--sis) n.

an infestation of the small intestine with the parasitic fluke Heterophyes heterophyes. Man becomes infected on eating raw or salted fish that contains the larval stage of the fluke. Symptoms include abdominal pain and diarrhoea; if the eggs reach the brain, spinal cord, and heart they produce serious lesions.

Back  -    New Search

heteroplasty (het-er-oh-plasti) n.

the grafting of tissue from an animal of one species to another of a different species.

Back  -    New Search

heteropsia (het-er-op-si) n.

different vision in each eye.

Back  -    New Search

heterosexuality (het-er-oh-seks-yoo-al-iti) n.

the pattern of sexuality in which sexual behaviour and thinking are directed towards people of the opposite sex.
—heterosexual adj., n.

Back  -    New Search

heterosis (het-er-oh-sis) n.

hybrid vigour: the increased sturdiness, resistance to disease, etc., of individuals whose parents are of different races or species.

Back  -    New Search

heterotopia (heterotopy) (het-er-oh-toh-pi) n.

the displacement of an organ or part of the body from its normal position.

Back  -    New Search

heterotropia (het-er-oh-troh-pi) n.

see STRABISMUS.

Back  -    New Search

heterozygous (het-er-oh-zy-gs) adj.

describing an individual in whom the members of a pair of genes determining a particular characteristic are dissimilar. See ALLELE. Compare HOMOZYGOUS.
—heterozygote n.

Back  -    New Search

hex- (hexa-) prefix

denoting six.

Back  -    New Search

hexachlorophane (heks--klor--fayn) n.

a disinfectant similar to phenol, formerly used in soaps and creams to treat skin disorders. Its use in medicinal products was limited by law in 1973 because of the toxic effects it might produce when absorbed into the body. Trade names: Dermalex , Ster-Zac D.C.

Back  -    New Search

hexamine (methenamine) (heks--meen) n.

an antiseptic with a wide range of antibacterial activity, used to treat infections and inflammation of the urinary tract, such as cystitis. Trade name: Hiprex .

Back  -    New Search

hexose (heks-ohz) n.

a simple sugar with six carbon atoms. Hexose sugars are the sugars most frequently found in food. The most important hexose is glucose.

Back  -    New Search

Hg

symbol for mercury.

Back  -    New Search

hiatus (hy-ay-ts) n.

an opening or aperture. For example, the diaphragm contains hiatuses for the oesophagus and aorta. h. hernia see HERNIA.

Back  -    New Search

Hib vaccine (hib) n.

a vaccine that gives protection against the bacterium Haemophilus influenzae type B, which is a common cause of meningitis in children under the age of two. The vaccine is given with the triple DPT vaccine during the first year of life.

Back  -    New Search

hiccup (hik-up) n.

abrupt involuntary lowering of the diaphragm and closure of the sound-producing folds at the upper end of the trachea, producing a characteristic sound as the breath is drawn in.
Hiccups, which usually occur repeatedly, may be caused by indigestion or more serious disorders, such as alcoholism. Medical name: singultus .

Back  -    New Search

Hickman catheter (hik-mn) n.

a fine plastic cannula inserted into a vein in the neck to allow administration of drugs and repeated blood samples. The catheter is tunnelled for several centimetres beneath the skin to prevent infection entering the bloodstream. It is used most frequently in patients receiving long-term chemotherapy.

Back  -    New Search

hidr- (hidro-) prefix

denoting sweat.

Back  -    New Search

hidradenitis suppurativa (hy-drad--ny-tis sup-yoor--tee-v) n.

an inflammatory condition of the sweat glands, which first become active at adolescence; it occurs in the armpits and groin.

Back  -    New Search

hidrosis (hid-roh-sis) n.

1 the excretion of sweat.

2 excessive sweating.
Top

Back  -    New Search

hidrotic (hid-rot-ik) n.

an agent that causes sweating. Parasympathomimetic drugs are hidrotics.

Back  -    New Search

Higginson's syringe (hig-in-snz) n.

a rubber syringe with a bulb in the centre that is compressed to force liquid in one direction to irrigate a body cavity. [A. Higginson (1808–84), British surgeon]

Back  -    New Search

hilum (hy-lm) n. (pl. hila)

a hollow situated on the surface of an organ, at which structures such as blood vessels and nerve fibres enter or leave it.
—hilar adj.

Back  -    New Search

hindbrain (hynd-brayn) n.

the part of the brain comprising the cerebellum, pons, and medulla oblongata.

Back  -    New Search

hindgut (hynd-gut) n.

the back part of the embryonic gut, which gives rise to part of the large intestine, the rectum, bladder, and urinary ducts. See also CLOACA.

Back  -    New Search

hindquarter amputation (hynd-kwort-er) n.

an operation involving removal of an entire leg and part or all of the pelvis associated with it. It is usually performed for soft tissue or bone sarcomas arising from the upper thigh, hip, or buttock. Compare FOREQUARTER AMPUTATION.

Back  -    New Search

hinge joint (hinj) n.

see GINGLYMUS.

Back  -    New Search

hip (hip) n.

the region of the body where the thigh bone (femur) articulates with the pelvis: the region on each side of the pelvis. h. bone (innominate bone ) a bone formed by the fusion of the ilium, ischium, and pubis. It articulates with the femur at the hip joint. h. girdle see PELVIC GIRDLE. h. joint the ball-and-socket joint between the head of the femur and the acetabulum (socket) of the ilium. h. replacement a surgical procedure for replacing a diseased hip joint with a prosthesis. See also ARTHROPLASTY.

Back  -    New Search

hippocampal formation (hip-oh-kam-pl) n.

a curved band of cortex lying within each cerebral hemisphere. It forms a portion of the limbic system and is involved in the complex physical aspects of behaviour governed by emotion and instinct.

Back  -    New Search

hippocampus (hip-oh-kam-ps) n.

a swelling in the floor of the lateral ventricle of the brain. It contains complex foldings of cortical tissue and is involved in the workings of the limbic system.
—hippocampal adj.

Back  -    New Search

Hippocratic oath (hip--krat-ik) n.

the oath taken by a doctor that binds him to observe the code of behaviour and practice followed by the Greek physician Hippocrates (460–370 BC), called the ‘Father of Medicine’.

Back  -    New Search

Hirschsprung's disease (heersh-spruungz) n.

a congenital condition in which the rectum and sometimes part of the lower colon have failed to develop a normal nerve network. The affected portion does not expand or conduct the contents of the bowel, which accumulate in and distend the upper section of the colon. See also MEGACOLON. [H. Hirschsprung (1830–1916), Danish physician]

Back  -    New Search

hirsutism (herss-yoo-tizm) n.

the presence of coarse pigmented hair on the face, chest, upper back, or abdomen in a female as a result of hyperandrogenism (excessive production of androgen). See also VIRILIZATION.

Back  -    New Search

hirudin (hi-roo-din) n.

an anticoagulant, present in the salivary glands of leeches and in certain snake venoms, that prevents blood coagulation by inhibiting the action of the enzyme thrombin.

Back  -    New Search

Hirudo (hi-roo-doh) n.

a genus of leeches. See LEECH.

Back  -    New Search

hist- (histio-, histo-) prefix

denoting tissue.

Back  -    New Search

histamine (hist--meen) n.

a compound derived from the amino acid histidine, found in nearly all tissues of the body. Histamine causes dilation of blood vessels and contraction of smooth muscle; it is an important mediator of inflammation and is released in large amounts after skin damage, producing flushing, a flare, and a weal. Histamine is also released in anaphylactic reactions. See also ANAPHYLAXIS, ANTIHISTAMINE.

Back  -    New Search

histidine (hist-i-deen) n.

an amino acid from which histamine is derived.

Back  -    New Search

histiocyte (hist-i--syt) n.

a fixed macrophage, i.e. one that is stationary within connective tissue.

Back  -    New Search

histiocytoma (hist-i-oh-sy-toh-m) n.

a tumour that contains macrophages or histiocytes.

Back  -    New Search

histiocytosis (hist-i-oh-sy-toh-sis) n.

any of a group of diseases, such as Gaucher's disease and Letterer-Siwe disease, in which there are abnormalities in certain large phagocytic cells (histiocytes), leading to biochemical defects.

Back  -    New Search

histocompatibility (hist-oh-km-pat-i-bil-iti) n.

the form of compatibility that depends upon tissue components, mainly specific glycoprotein antigens in cell membranes. A high degree of histocompatibility is necessary for a tissue graft or organ transplant to be successful.
—histocompatible adj.

Back  -    New Search

histogenesis (hist-oh-jen-i-sis) n.

the formation of tissues.

Back  -    New Search

histoid (hist-oid) adj.

1 resembling normal tissue.

2 composed of one type of tissue.
Top

Back  -    New Search

histological grade (hist-oh-loj-ikl) n.

the degree of differentiation of a tumour, such as a breast tumour.

Back  -    New Search

histology (hiss-tol-ji) n.

the study of the structure of tissues by means of special staining techniques combined with light and electron microscopy.
—histological adj.

Back  -    New Search

histolysis (hiss-tol-i-sis) n.

disintegration of tissue.

Back  -    New Search

histone (hist-ohn) n.

a simple protein that combines with a nucleic acid to form a nucleoprotein.

Back  -    New Search

histoplasmin (hist-oh-plaz-min) n.

a preparation of antigenic material from a culture of the fungus Histoplasma capsulatum, used to test for the presence of histoplasmosis by subcutaneous injection.

Back  -    New Search

histoplasmosis (hist-oh-plaz-moh-sis) n.

an infection caused by inhaling spores of the fungus Histoplasma capsulatum. The primary pulmonary form usually produces no symptoms or harmful effects. Occasionally, progressive histoplasmosis, which resembles tuberculosis, develops. The fungus may spread via the bloodstream to attack the liver, spleen, lymph nodes, or intestine. Symptomatic disease is treated with intravenous amphotericin-B.

Back  -    New Search

histotoxic (hist-oh-toks-ik) adj.

poisonous to tissues: applied to certain substances and conditions.

Back  -    New Search

HIV (human immunodeficiency virus) n.

a retrovirus responsible for AIDS. HIV-1 the variety of HIV most common in Western countries. HIV-2 the variety of HIV most common in Africa. See also HTLV.

Back  -    New Search

hives (hyvz) n.

see URTICARIA.

Back  -    New Search

HLA system n.

human leucocyte antigen system: a series of four gene families (termed A, B, C, and D) that code for polymorphic proteins expressed on the surface of most nucleated cells. Individuals inherit from each parent one gene (or set of genes) for each subdivision of the HLA system. If two individuals have identical HLA types, they are said to be histocompatible. Successful tissue transplantation requires a minimum number of HLA differences between donor and recipient tissues.

Back  -    New Search

hobnail liver (hob-nayl) n.

the liver of a patient with cirrhosis, which has a knobbly appearance caused by regenerating nodules separated by bands of fibrous tissue.

Back  -    New Search

Hodgkin's disease (Hodgkin's lymphoma) (hoj-kinz) n.

a malignant disease of lymphatic tissues - a form of lymphoma - usually characterized by painless enlargement of one or more groups of lymph nodes in the neck, armpits, groin, chest, or abdomen; the spleen, liver, bone marrow, and bones may also be involved. Treatment may include surgery, radiotherapy, drug therapy (using drugs such as procarbazine and prednisone), or a combination of these. [T. Hodgkin (1798–1866), British physician]

Back  -    New Search

hole in the heart (hohl) n.

see SEPTAL DEFECT.

Back  -    New Search

holistic (hoh-list-ik) adj.

describing an approach to patient care in which the physiological, psychological, and social factors of the patient's condition are taken into account, rather than just the diagnosed disease. The term is applied to a range of orthodox and unorthodox methods of treatment. See also ALTERNATIVE MEDICINE.

Back  -    New Search

holo- prefix

denoting complete or entire.

Back  -    New Search

holocrine (hol--kryn) adj.

describing a gland or type of secretion in which the entire cell disintegrates when the product is released.

Back  -    New Search

Homans' sign (hoh-mnz) n.

pain felt in the calf when the foot is flexed backwards: a sign of phlebothrombosis. [J. Homans (1877–1954), US physician]

Back  -    New Search

home nurse (hohm) n.

see DISTRICT NURSE.

Back  -    New Search

homeo- (homoeo-) prefix

denoting similar; like.

Back  -    New Search

homeopathic (homoeopathic) (hoh-mi--path-ik) adj.

1 of or relating to homeopathy.

2 infinitesimally small, as applied to the dose of a drug.
Top

Back  -    New Search

homeopathy (homoeopathy) (hoh-mi-op--thi) n.

a system of medicine based on the theory that ‘like cures like’. The patient is treated with extremely small quantities of drugs that are themselves capable of producing symptoms of his particular disease. The system was founded by Samuel Hahnemann (1755–1843). See also ALTERNATIVE MEDICINE.
—homeopathist n.

Back  -    New Search

homeostasis (hoh-mi-oh-stay-sis) n.

the physiological process by which the internal systems of the body are maintained at equilibrium, despite variations in the external conditions.
—homeostatic adj.

Back  -    New Search

homo- prefix

denoting the same or common.

Back  -    New Search

homocystinuria (hoh-moh-sis-tin-yoor-i) n.

an inborn error of metabolism caused by an enzyme deficiency resulting in an excess of homocysteine (an intermediate in the synthesis of the amino acid cysteine) in the blood and the presence of homocystine (an oxidized form of cysteine) in the urine. Clinically affected individuals are mentally retarded, excessively tall with long fingers (due to overgrowth of bones), and have a tendency to form blood clots in the veins and arteries.

Back  -    New Search

homoeopathy (hoh-mi-op--thi) n.

see HOMEOPATHY.

Back  -    New Search

homogenize (h-moj-i-nyz) vb.

to reduce material to a uniform consistency, e.g. by crushing and mixing.
—homogenization n.

Back  -    New Search

homogentisic acid (hoh-moh-jen-tis-ik) n.

a product formed during the metabolism of the amino acids phenylalanine and tyrosine. In normal individuals homogentisic acid is oxidized by the enzyme homogentisic acid oxidase . In rare cases this enzyme is lacking and alcaptonuria results.

Back  -    New Search

homograft (allograft) (hom--grahft) n.

a living tissue or organ graft between two members of the same species. Unless the graft is from an identical twin, it will not survive unless the recipient is treated to suppress his body's automatic rejection of the foreign tissue.

Back  -    New Search

homoiothermic (hoh-moi--therm-ik) adj.

warm-blooded: able to maintain a constant body temperature independently of, and despite variations in, the temperature of the surroundings. Compare POIKILOTHERMIC.
—homoiothermy n.

Back  -    New Search

homolateral (hoh-moh-lat-er-l) adj.

see IPSILATERAL.

Back  -    New Search

homologous (hoh-mol--gs) adj.

1 (in anatomy) describing organs or parts that have the same basic structure and evolutionary origin, but not necessarily the same function or superficial structure. Compare ANALOGOUS.

2 (in genetics) describing a pair of chromosomes of similar shape and size and having identical gene loci.
Top

Back  -    New Search

homonymous (hoh-mon-i-ms) adj.

describing a visual defect in which the visual field to one side of the body is restricted in both eyes (see HEMIANOPIA).

Back  -    New Search

homoplasty (hoh-moh-plasti) n.

surgical repair of defective or damaged tissues or organs with a homograft.

Back  -    New Search

homosexuality (hoh-moh-seks-yoo-al-iti) n.

the condition of being sexually attracted, covertly or overtly, by members of one's own sex: it can affect either sex (see also LESBIANISM). Homosexuality is no longer regarded as a psychological disorder; those seeking help are more likely to benefit from counselling to reduce any anxiety and guilt than from therapy to change their sexual orientation.
—homosexual adj., n.

Back  -    New Search

homozygous (hoh-moh-zy-gs) adj.

describing an individual in whom the members of a pair of genes determining a particular characteristic are identical. See ALLELE. Compare HETEROZYGOUS.
—homozygote n.

Back  -    New Search

hook (huuk) n.

a surgical instrument with a bent or curved tip, used to hold, lift, or retract tissue at operation.

Back  -    New Search

hookworm (huuk-werm) n.

either of two nematode worms, Necator americanus or Ancylostoma duodenale, which live as parasites in the intestine of man. h. disease a condition resulting from an infestation of the small intestine by hookworms. Heavy hookworm infections may cause considerable damage to the wall of the intestine, leading to severe anaemia. Bephenium hydroxynaphthoate is used in treatment.

Back  -    New Search

hordeolum (hor-dee--lum) n.

see STYE.

Back  -    New Search

hormone (hor-mohn) n.

a substance that is produced by an endocrine gland in one part of the body, passes into the bloodstream, and is carried to other (distant) organs or tissues, where it acts to modify their structure or function. Examples of hormones are corticosteroids, growth hormone, and androgens.

Back  -    New Search

hormone replacement therapy (HRT) n.

the use of female hormones for the relief of symptoms resulting from cessation of ovarian function, either at the time of the natural menopause or following surgical removal of the ovaries. Oestrogenic hormones may be prescribed orally, by subcutaneous implant, or transdermally (as skin patches or gel); a combination of progestogen with oestrogen is preferred if the woman has retained her uterus. HRT is also effective in preventing osteoporosis.

Back  -    New Search

horn (horn) n.

(in anatomy) a process, outgrowth, or extension of an organ or other structure. It is often paired.

Back  -    New Search

Horner's syndrome (hor-nerz) n.

a syndrome consisting of a constricted pupil, ptosis, and an absence of sweating over the affected side of the face. The symptoms are due to a disorder of the sympathetic nerves in the brainstem or cervical (neck) region. [J. F. Horner (1831–86), Swiss ophthalmologist]

Back  -    New Search

horseshoe kidney (hors-shoo) n.

an anatomical variation in kidney development whereby the lower poles of both kidneys are joined together. This usually causes no trouble but it may be associated with impaired drainage of urine from the kidney by the ureters.

Back  -    New Search

Horton's syndrome (hor-t'nz) n.

a severe headache caused by the release of histamine. [B. T. Horton (20th century), US physician]

Back  -    New Search

hospice (hos-pis) n.

an institution that specializes in the care of terminally ill patients, with special concern for death with dignity.

Back  -    New Search

hospital (hos-pi-t'l) n.

an institution providing medical or psychiatric care and treatment of patients. community h. a small hospital, which may be staffed by general practitioners, providing care for patients for whom home care is not practicable. day h. a hospital at which patients are cared for during the day, returning home at night. district general h. a hospital that provides sufficient basic services for the population of a health district.

Back  -    New Search

hospital infection n.

see NOSOCOMIAL INFECTION.

Back  -    New Search

host (hohst) n.

an animal or plant in or upon which a parasite lives. intermediate h. a host in which the parasite passes its larval or asexual stages. definitive h. a host in which the parasite develops to its sexual stage.

Back  -    New Search

hourglass contraction (ow-er-glahs) n.

constriction of an organ at its centre as a result of abnormal muscular contraction. Hourglass contraction may be a complication of labour, tending to trap the placenta in the upper part of the constricted uterus and possibly leading to excessive blood loss after delivery.

Back  -    New Search

hourglass stomach n.

a deformity of the stomach in which the ‘waist’ is constricted by fibrosis caused by a chronic peptic ulcer, producing an upper and a lower cavity separated by a narrow channel.

Back  -    New Search

housemaid's knee (prepatellar bursitis) (howss-maydz) n.

a fluid-filled swelling of the bursa in front of the kneecap, often resulting from frequent kneeling. See also BURSITIS.

Back  -    New Search

HPV n.

see HUMAN PAPILLOMAVIRUS.

Back  -    New Search

H_2-receptor antagonist n.

see ANTIHISTAMINE.

Back  -    New Search

HRT n.

see HORMONE REPLACEMENT THERAPY.

Back  -    New Search

HSE n.

see HEALTH AND SAFETY EXECUTIVE.

Back  -    New Search

HSV n.

herpes simplex virus: see HERPES.

Back  -    New Search

5-HT n.

5-hydroxytryptamine: see SEROTONIN.

Back  -    New Search

HTLV (human T-cell lymphocytotrophic virus) n.

a family of viruses that includes the AIDS virus, HTLV-III (or HIV). Other HTLV viruses may cause lymphomas and leukaemias.

Back  -    New Search

human chorionic gonadotrophin (HCG) (hew-mn kor-i-on-ik) n.

a hormone, similar to the pituitary gonadotrophins, that is produced by the placenta during pregnancy. Large amounts of HCG are excreted in the urine, and this is used as the basis for most pregnancy tests. HCG is given by injection to treat such conditions as delayed puberty, undescended testes, and premenstrual tension. See also TRIPLE MARKER TEST.

Back  -    New Search

human immunodeficiency virus n.

see HIV.

Back  -    New Search

human leucocyte antigen system n.

see HLA SYSTEM.

Back  -    New Search

human papillomavirus (HPV) (pap-i-loh-m-vy-rs) n.

a virus – a member of the papovavirus group – that causes warts, including genital warts. Certain strains are considered to be causative factors in the development of anal and genital cancers, especially cervical cancer. HPV is one of the most common sexually transmitted infections.

Back  -    New Search

humectant (hew-mek-tnt)

1 n. a substance that is used for moistening.

2 adj. causing moistening.
Top

Back  -    New Search

humerus (hew-mer-s) n.

the bone of the upper arm. The head of the humerus articulates with the scapula at the shoulder joint. At the lower end of the shaft the trochlea articulates with the ulna and part of the radius.

Back  -    New Search

humoral (hew-mer-l) adj.

circulating in the bloodstream; humoral immunity requires circulating antibodies.

Back  -    New Search

humour (hew-mer) n.

a body fluid. See AQUEOUS HUMOUR, VITREOUS HUMOUR.

Back  -    New Search

hunger pain (hung-er) n.

pain in the upper abdomen that is relieved by taking food. It is associated with a duodenal ulcer.

Back  -    New Search

Hunner's ulcer (hun-erz) n.

see INTERSTITIAL CYSTITIS. [G. L. Hunner (1868–1957), US urologist]

Back  -    New Search

Hunter's syndrome (hunt-erz) n.

a hereditary disorder caused by deficiency of an enzyme that results in the accumulation of protein-carbohydrate complexes and fats in the cells of the body. This leads to mental retardation, enlargement of the liver and spleen, and prominent coarse facial features (gargoylism ). Medical name: mucopolysaccharidosis type II. [C. H. Hunter (1872–1955), US physician]

Back  -    New Search

Huntington's disease (Huntington's chorea) (hunt-ing-tnz) n.

a hereditary disease caused by a defect in a single gene that is inherited as an autosomal dominant characteristic, tending to appear in half of the children of the parents with this condition. Symptoms, which begin to appear in early middle age, include unsteady gait and jerky involuntary movements (see CHOREA), accompanied later by behavioural changes and progressive dementia. [G. Huntington (1850–1916), US physician]

Back  -    New Search

Hurler's syndrome (hoor-lerz) n.

a hereditary disorder caused by deficiency of an enzyme that results in the accumulation of protein-carbohydrate complexes and fats in the cells of the body. This leads to severe mental retardation, enlargement of the liver and spleen, heart defects, deformities of the bones, and coarsening and thickening of the facial features (gargoylism ). Medical name: mucopolysaccharidosis type 1. [G. Hurler (1889–1965), Austrian paediatrician]

Back  -    New Search

Hutchinson's teeth (huch-in-snz) pl. n.

narrowed and notched permanent incisor teeth: a sign of congenital syphilis. [J. Hutchinson (1828–1913), British surgeon]

Back  -    New Search

hyal- (hyalo-) prefix

denoting 1 glassy; transparent.

2 hyalin.
Top

3 the vitreous humour of the eye.
Top

Back  -    New Search

hyalin (hy--lin) n.

a clear glassy material produced as the result of degeneration in certain tissues, particularly connective tissue and epithelial cells.

Back  -    New Search

hyaline cartilage (hy--lin) n.

see CARTILAGE.

Back  -    New Search

hyaline membrane disease n.

see RESPIRATORY DISTRESS SYNDROME.

Back  -    New Search

hyalitis (hy--ly-tis) n.

inflammation of the vitreous body of the eye. asteroid h. see ASTEROID HYALOSIS.

Back  -    New Search

hyaloid membrane (hy--loid) n.

the transparent membrane that surrounds the vitreous humour of the eye, separating it from the retina.

Back  -    New Search

hyaluronidase (hy-l-yoor-on-i-dayz) n.

an enzyme that increases the permeability of connective tissue. Hyaluronidase is found in the testes, in semen, and in other tissues.

Back  -    New Search

hybrid (hy-brid) n.

the offspring of a cross between two genetically unlike individuals. A hybrid, whose parents are usually of different species or varieties, is often sterile.

Back  -    New Search

HYCOSY (hysterosalpingo-contrast sonography) n.

an out-patient technique that tests for blocked Fallopian tubes. Using transvaginal ultrasonography and an echo contrast medium, flow along the tubes can be reliably visualized. See also DOPPLER ULTRASOUND.

Back  -    New Search

hydatid (hy-d-tid) n.

a bladder-like cyst formed in various human tissues following the growth of the larval stage of an Echinococcus tapeworm. alveolar h. an aggregate of small cysts, which enlarge by budding off external daughter cysts. unilocular h. a single large fluid-filled cyst, bound by a fibrous capsule, that gives rise internally to smaller daughter cysts. See also HYDATID DISEASE.

Back  -    New Search

hydatid disease (hydatidosis, echinococciasis, echinococcosis) n.

a condition resulting from the presence in the liver, lungs, or brain of hydatid cysts. Alveolar hydatids form malignant tumours; unilocular hydatids exert pressure as they grow and thereby damage surrounding tissues.

Back  -    New Search

hydatidiform mole (hydatid mole, vesicular mole) (hy-d-tid-i-form) n.

a collection of fluid-filled sacs that develop when the chorion degenerates in early pregnancy. The embryo dies, the uterus enlarges, and there is a discharge of pinkish liquid and cysts from the vagina. A malignant condition may subsequently develop (see CHORIONEPITHELIOMA).

Back  -    New Search

hydatidosis (hy-d-tid-oh-sis) n.

see HYDATID DISEASE.

Back  -    New Search

hydr- (hydro-) prefix

denoting water or a watery fluid.

Back  -    New Search

hydraemia (hy-dree-mi) n.

the presence in the blood of more than the normal proportion of water.

Back  -    New Search

hydralazine (hy-dral--zeen) n.

a drug that lowers blood presure and is administered by mouth or injection, usually in conjunction with diuretics, in the treatment of hypertension. Trade name: Apresoline .

Back  -    New Search

hydramnios (hydramnion) (hy-dram-ni-s) n.

the presence of an abnormally large amount of amniotic fluid surrounding the fetus from about the 20th week of pregnancy.

Back  -    New Search

hydrargyria (hy-drar-jy-ri) n.

see MERCURIALISM.

Back  -    New Search

hydrarthrosis (hy-drar-throh-sis) n.

swelling at a joint caused by excessive synovial fluid. The condition usually involves the knees and may be recurrent.

Back  -    New Search

hydrate (hy-drayt)

1 vb. to undergo treatment or impregnation with water.
—hydration n.
2 n. a chemical compound in which one or more molecules of water are combined with a molecule of another substance.
Top

Back  -    New Search

hydrocalycosis (hy-droh-kal-i-koh-sis) n.

see CALIECTASIS.

Back  -    New Search

hydrocele (hy-droh-seel) n.

the accumulation of watery liquid in a sac, usually the sac surrounding the testes. This condition is characterized by painless enlargement of the scrotum.

Back  -    New Search

hydrocephalus (hy-droh-sef--ls) n.

an abnormal increase in the amount of cerebrospinal fluid within the ventricles of the brain. In childhood, before the sutures of the skull have fused, hydrocephalus makes the head enlarge. In adults, hydrocephalus raises the intracranial pressure, with consequent drowsiness and vomiting. Spina bifida may be associated with hydrocephalus in childhood.

Back  -    New Search

hydrochloric acid (hy-dr-klor-ik) n.

a strong acid present, in a very dilute form, in gastric juice. The secretion of excess hydrochloric acid by the stomach results in the condition hyperchlorhydria.

Back  -    New Search

hydrochlorothiazide (hy-dr-klor-oh-th'y--zyd) n.

a diuretic administered by mouth to treat fluid retention (oedema) and high blood pressure. Trade names: Esidrex , Hydrosaluric .

Back  -    New Search

hydrocortisone (hy-droh-kor-tiz-ohn) n.

a pharmaceutical preparation of the steroid hormone cortisol. Hydrocortisone is used to treat adrenal failure (Addison's disease) and inflammatory, allergic, and rheumatic conditions (including rheumatoid arthritis, colitis, and eczema). It may be given by mouth, by injection, or in the form of a cream or ointment.

Back  -    New Search

hydrocyanic acid (prussic acid) (hy-droh-sy-an-ik) n.

an intensely poisonous volatile acid that can cause death within a minute if inhaled. It smells of bitter almonds. See CYANIDE.

Back  -    New Search

hydroflumethiazide (hy-droh-floo-meth-l--zyd) n.

a diuretic administered by mouth to treat fluid retention (oedema) and high blood pressure. Trade name: Hydrenox .

Back  -    New Search

hydrogen (hy-dr-jn) n.

a colourless gas that is combined with oxygen to form water (H_2O) and with various other molecules (chiefly carbon and oxygen) to form all organic compounds. Symbol: H. h. ion concentration see pH.

Back  -    New Search

hydrogen peroxide (per-ok-syd) n.

a colourless liquid used as a disinfectant for cleansing wounds and, diluted, as a deodorant mouthwash or as ear drops for removing wax. Formula:
H_2O_2
.

Back  -    New Search

hydrolysis (hy-drol-i-sis) n.

any chemical reaction in which a compound and water react together to produce other compounds.

Back  -    New Search

hydroma (hy-droh-m) n.

see HYGROMA.

Back  -    New Search

hydrometer (hy-drom-it-er) n.

an instrument for measuring the density or relative density of liquids.
—hydrometry n.

Back  -    New Search

hydrometra (hy-droh-mee-tr) n.

an abnormal accumulation of watery fluid in the uterus.

Back  -    New Search

hydronephrosis (hy-droh-ni-froh-sis) n.

distension and dilatation of the pelvis of the kidney. This is due to an obstruction to the free flow of urine from the kidney. Surgical relief by pyeloplasty is advisable to avoid the back pressure atrophy of the kidney and the complications of infection and stone formation.
—hydronephrotic adj.

Back  -    New Search

hydropericarditis (hy-droh-pe-ri-kar-dy-tis) n.

see HYDROPERICARDIUM.

Back  -    New Search

hydropericardium (hy-droh-pe-ri-kar-di-m) n.

accumulation of a clear serous fluid within the membranous sac surrounding the heart. It occurs in many cases of pericarditis (hydropericarditis ).

Back  -    New Search

hydroperitoneum (hy-droh-pe-ri-tn-ee-m) n.

see ASCITES.

Back  -    New Search

hydrophobia (hy-dr-foh-bi) n.

see RABIES.

Back  -    New Search

hydrophthalmos (hy-drof-thal-ms) n.

see BUPHTHALMOS.

Back  -    New Search

hydropneumoperitoneum (hy-droh-new-moh-pe-ri-tn-ee-m) n.

the presence of fluid and gas in the peritoneal cavity.

Back  -    New Search

hydropneumothorax (hy-droh-new-moh-thor-aks) n.

air and fluid in the pleural cavity. An effusion of serous fluid commonly complicates a pneumothorax, and must be drained.

Back  -    New Search

hydrops (hy-drops) n.

an abnormal accumulation of fluid in body tissues or cavities. corneal h. the sudden painful accumulation of fluid in the cornea seen in keratoconus. It results in a sudden reduction of vision. See also HYDROPS FETALIS, MÉNIÈRE'S DISEASE (ENDOLYMPHATIC HYDROPS).

Back  -    New Search

hydrops fetalis (fee-tah-lis) n.

severe oedema that develops before birth. The excess fluid accumulates in the body cavities, especially in the peritoneal and pleural cavities. The commonest cause is severe anaemia associated with haemolytic disease of the newborn. Congenital heart abnormalities and kidney and lung disease are other causes.

Back  -    New Search

hydrorrhachis (hy-dror-r-kis) n.

an abnormal accumulation of watery fluid in the space surrounding the spinal cord.

Back  -    New Search

hydrosalpinx (hy-droh-sal-pinks) n.

the accumulation of watery fluid in one of the Fallopian tubes, which becomes swollen.

Back  -    New Search

hydrostatic accouchement (hy-droh-stat-ik) n.

see ACCOUCHMENT.

Back  -    New Search

hydrotherapy (hy-droh-th'e-r-pi) n.

the use of water in the treatment of disorders: today restricted in orthodox medicine to exercises in remedial swimming pools for the rehabilitation of arthritic or partially paralysed patients.

Back  -    New Search

hydrothorax (hy-droh-thor-aks) n.

fluid in the pleural cavity. See also HYDROPNEUMOTHORAX.

Back  -    New Search

hydrotubation (hy-droh-tew-bay-shn) n.

the introduction of a fluid (usually a dye) through the cervix (neck) of the uterus under pressure to allow visualization, by laparoscopy, of the passage of the dye through the Fallopian tubes. It is used to test whether or not the tubes are blocked in the investigation of infertility.

Back  -    New Search

hydroureter (hy-droh-yoor-ee-ter) n.

an accumulation of urine in one of the ureters, usually resulting from obstruction of the ureter by a stone or a misplaced artery.

Back  -    New Search

hydroxocobalamin (hy-droks-oh-koh-bal--min) n.

a cobalt-containing drug administered by injection to treat conditions involving vitamin B_12 deficiency, such as pernicious anaemia. Trade names: Cobalin-H , Neo-Cytamen .

Back  -    New Search

hydroxyapatite (hy-droks-i-ap--tyt) n.

1 the crystalline component of bones and teeth, consisting of a complex form of calcium phosphate.

2 a biocompatible ceramic material that is a synthetic form of natural hydroxyapatite. It is used to coat some joint replacement prostheses, which encourages bone to grow onto the implant, and is also used in some forms of middle-ear surgery.
Top

Back  -    New Search

hydroxychloroquine (hy-droks-i-klor--kwin) n.

a drug, similar to chloroquine, used mainly to treat lupus erythematosus and rheumatoid arthritis. Trade name: Plaquenil .

Back  -    New Search

hydroxyprogesterone (hy-droks-i-proh-jes-ter-ohn) n.

a synthetic female sex hormone (see PROGESTOGEN) administered by injection to prevent miscarriage and to treat menstrual disorders. Trade name: Proluton .

Back  -    New Search

hydroxyproline (hy-droks-i-proh-leen) n.

a compound, similar in structure to the amino acids, found only in collagen.

Back  -    New Search

5-hydroxytryptamine (hy-droks-i-trip-t-meen) n.

see SEROTONIN.

Back  -    New Search

hydroxyurea (hy-droks-i-yoor-ee-) n.

a drug that prevents cell growth and is administered by mouth to treat some types of leukaemia. Hydroxyurea may lower the white cell content of the blood due to its effects on the bone marrow. Trade name: Hydrea .

Back  -    New Search

hydroxyzine (hy-droks-i-zeen) n.

an antihistamine drug with sedative properties, administered by mouth to relieve anxiety, tension, and agitation and to treat nausea and vomiting. Trade name: Atarax .

Back  -    New Search

hygiene (hy-jeen) n.

the science of health and the study of ways of preserving it, particularly by promoting cleanliness.

Back  -    New Search

hygr- (hygro-) prefix

denoting moisture.

Back  -    New Search

hygroma (hydroma) (hy-groh-m) n.

a type of cyst. It may develop from a lymphangioma (cystic h. ) or from the liquified remains of a subdural haematoma (subdural h. ).

Back  -    New Search

hygrometer (hy-grom-i-ter) n.

an instrument for measuring the relative humidity of the atmosphere, i.e. the ratio of the moisture in the air to the moisture it would contain if it were saturated at the same temperature and pressure.

Back  -    New Search

hymen (hy-mn) n.

the membrane that covers the opening of the vagina at birth but usually perforates spontaneously before puberty.

Back  -    New Search

hymenectomy (hy-mn-ek-tmi) n.

surgical removal of the hymen to enlarge the vaginal opening.

Back  -    New Search

hymenotomy (hy-mn-ot-mi) n.

incision of the hymen. This operation may be performed in cases of imperforate hymen. It is also carried out to alleviate dyspareunia (painful intercourse).

Back  -    New Search

hyo- prefix

denoting the hyoid bone.

Back  -    New Search

hyoid bone (hy-oid) n.

a small isolated U-shaped bone in the neck, below and supporting the tongue. It is held in position by muscles and ligaments between it and the styloid process of the temporal bone.

Back  -    New Search

hyoscine (scopolamine) (hy--seen) n.

a drug that prevents muscle spasm (see PARASYMPATHOLYTIC). It is used in the treatment of gastric or duodenal ulcers, to relax the uterus in labour, for preoperative medication, and for motion sickness. It is administered by mouth or injection. Trade names: Buscopan , Scopoderm .

Back  -    New Search

hyp- (hypo-) prefix

denoting 1 deficiency, lack, or small size.

2 (in anatomy) below; beneath.
Top

Back  -    New Search

hypaemia (hy-pee-mi) n.

a decrease in the blood supply to an organ or tissue. Compare HYPERAEMIA.

Back  -    New Search

hypalgesia (hy-pal-jeez-i) n.

an abnormally low sensitivity to pain.

Back  -    New Search

hyper- prefix

denoting 1 excessive; abnormally increased.

2 (in anatomy) above.
Top

Back  -    New Search

hyperacidity (hy-per--sid-iti) n.

an abnormally increased concentration of acid, especially in the stomach (see HYPERCHLORHYDRIA).

Back  -    New Search

hyperactivity (hy-per-ak-tiv-iti) n.

see HYPERKINESIA.

Back  -    New Search

hyperacusis (hy-per--kew-sis) n.

abnormally acute hearing or painful sensitivity to sounds.

Back  -    New Search

hyperadrenalism (hy-per--dren--lizm) n.

overactivity of the adrenal glands. See CUSHING'S SYNDROME.

Back  -    New Search

hyperaemia (hy-per-ee-mi) n.

the presence of excess blood in the vessels supplying a part of the body. active h. (arterial h. ) hyperaemia that occurs when the arterioles are relaxed and there is an increased blood flow. passive h. hyperaemia that occurs when the blood flow from the affected part is obstructed.

Back  -    New Search

hyperaesthesia (hy-per-ees-theez-i) n.

excessive sensibility, especially of the skin.

Back  -    New Search

hyperalgesia (hy-per-al-jeez-i) n.

an abnormal state of increased sensitivity to painful stimuli.

Back  -    New Search

hyperandrogenism (hy-per-an-droj-in-izm) n.

excessive secretion of androgen in women. It is associated with hirsutism, acne, sparse or infrequent menstruation (oligomenorrhoea), metrorrhagia, absent or infrequent ovulation, infertility, endometrial hyperplasia, hyperlipidaemia, hyperglycaemia, and hypertension. See also VIRILIZATION.

Back  -    New Search

hyperbaric (hy-per-ba-rik) adj.

at a pressure greater than atmospheric pressure. h. oxygenation a technique for exposing a patient to oxygen at high pressure. It is used to treat compressed air illness, carbon monoxide poisoning, gas gangrene, and acute breathing difficulties.

Back  -    New Search

hypercalcaemia (hy-per-kal-see-mi) n.

the presence in the blood of an abnormally high concentration of calcium. It may be caused by excessive ingestion of vitamin D. idiopathic h. congenital hypercalcaemia that is associated with mental retardation and heart defects. Compare HYPOCALCAEMIA.

Back  -    New Search

hypercalcinuria (hypercalcuria) (hy-per-kal-sin-yoor-i) n.

the presence in the urine of an abnormally high concentration of calcium.

Back  -    New Search

hypercapnia (hypercarbia) (hy-per-kap-ni) n.

the presence in the blood of an abnormally high concentration of carbon dioxide.

Back  -    New Search

hypercatabolism (hy-per-k-tab-l-izm) n.

an abnormally increased rate of metabolic breakdown of substances in the body. See CATABOLISM.
—hypercatabolic adj.

Back  -    New Search

hyperchloraemia (hy-per-klor-ee-mi) n.

the presence in the blood of an abnormally high concentration of chloride.

Back  -    New Search

hyperchlorhydria (hy-per-klor-hy-dri) n.

a greater than normal secretion of hydrochloric acid by the stomach, usually associated with a duodenal ulcer.

Back  -    New Search

hypercholesterolaemia (hy-per-kl-est-er-ol-ee-mi) n.

see CHOLESTEROL.

Back  -    New Search

hyperchromatism (hy-per-kroh-m-tizm) n.

the property of the nuclei of certain cells (for example, those of tumours) to stain more deeply than normal.
—hyperchromatic adj.

Back  -    New Search

hyperdactylism (polydactylism) (hy-per-dak-til-izm) n.

the condition of having more than the normal number of fingers or toes.

Back  -    New Search

hyperdynamia (hy-per-dy-nay-mi) n.

excessive activity of muscles.

Back  -    New Search

hyperemesis (hy-per-em-i-sis) n.

severe vomiting. h. gravidarum severe vomiting during pregnancy. It starts in early pregnancy and may continue to produce marked dehydration and subsequent liver damage. The condition may worsen in spite of active treatment; in this case it may be necessary to terminate the pregnancy.

Back  -    New Search

hyperextension (hy-per-iks-ten-shn) n.

extension of a joint or limb beyond its normal limit.

Back  -    New Search

hyperflexion (hy-per-flek-shn) n.

excessive and forceful flexion of a limb or other part.

Back  -    New Search

hyperglycaemia (hy-per-gly-see-mi) n.

an excess of glucose in the bloodstream. It may occur in a variety of diseases, most notably in diabetes mellitus.

Back  -    New Search

hyperidrosis (hyperhidrosis) (hy-per-id-roh-sis) n.

excessive sweating, which may occur in certain diseases, such as fevers or thyrotoxicosis, or following the use of certain drugs.

Back  -    New Search

hyperinsulinism (hy-per-ins-yoo-lin-izm) n.

1 excessive secretion of the hormone insulin by the islet cells of the pancreas.

2 metabolic disturbance due to administration of too much insulin.
Top

Back  -    New Search

hyperkalaemia (hy-per-kal-ee-mi) n.

the presence in the blood of an abnormally high concentration of potassium, usually due to failure of the kidneys to excrete it. See also ELECTROLYTE.

Back  -    New Search

hyperkeratosis (hy-per-ke-r-toh-sis) n.

thickening of the outer horny layer of the skin. It may occur as an inherited disorder, affecting the palms and soles.

Back  -    New Search

hyperkinesia (hyperactivity) (hy-per-ki-neez-i) n.

a state of overactive restlessness in children. See ATTENTION DEFICIT DISORDER.
—hyperkinetic (hy-per-ki-net-ik) adj.

Back  -    New Search

hyperlipidaemia (hyperlipaemia) (hy-per-lip-id-ee-mi) n.

the presence in the blood of an abnormally high concentration of fats.

Back  -    New Search

hypermetropia (long-sightedness) (hy-per-mi-troh-pi) n.

the condition in which parallel light rays are brought to a focus behind the retina when the accommodation is relaxed. Normal vision can be restored by wearing spectacles with convex lenses (see illustration). Compare EMMETROPIA, MYOPIA.

Back  -    New Search

hypermotility (hy-per-moh-til-iti) n.

excessive movement or activity, especially of the stomach or intestine.

Back  -    New Search

hypernatraemia (hy-per-n-tree-mi) n.

the presence in the blood of an abnormally high concentration of sodium. See also ELECTROLYTE.

Back  -    New Search

hypernephroma (Grawitz tumour, renal cell carcinoma) (hy-per-ni-froh-m) n.

a malignant tumour of kidney cells. It may be present for some years before giving rise to symptoms, which include fever, loin pain, and blood in the urine. Treatment is by surgery but tumours are apt to recur locally.

Back  -    New Search

hyperopia (hy-per-oh-pi) n.

the usual US term for hypermetropia.

Back  -    New Search

hyperostosis (hy-per-os-toh-sis) n.

excessive enlargement of the outer layer of a bone. It commonly affects the frontal bone of the skull (h. frontalis ). infantile cortical h. (Caffey's disease ) swelling of the long bones, jaw, and shoulder blade, associated with pain and fever, in infants under six months.

Back  -    New Search

hyperparathyroidism (hy-per-pa-r-th'y-roid-izm) n.

overactivity of the parathyroid glands. See VON RECKLINGHAUSEN'S DISEASE.

Back  -    New Search

hyperphagia (hy-per-fay-ji) n.

excessive overeating. See BULIMIA.

Back  -    New Search

hyperpiesia (hy-per-py-ee-zi) n.

see HYPERTENSION.

Back  -    New Search

hyperpituitarism (hy-per-pit-yoo-it-er-izm) n.

overactivity of the pituitary gland, resulting in acromegaly or gigantism.

Back  -    New Search

hyperplasia (hy-per-play-zi) n.

the increased production and growth of normal cells in a tissue or organ. See also ENDOMETRIAL (HYPERPLASIA). Compare HYPERTROPHY, NEOPLASM.

Back  -    New Search

hyperpnoea (hy-perp-nee-) n.

an increase in the rate of breathing that is proportional to an increase in metabolism; for example, on exercise. Compare HYPERVENTILATION.

Back  -    New Search

hyperpyrexia (hy-per-py-reks-i) n.

a rise in body temperature above 106°F (41.1°C). See FEVER.

Back  -    New Search

hypersecretion (hy-per-si-kree-shn) n.

excessive secretion, as of hydrochloric acid by the stomach (see HYPERCHLORHYDRIA).

Back  -    New Search

hypersensitive (hy-per-sen-si-tiv) adj.

prone to respond abnormally to the presence of a particular antigen, which may cause a variety of tissue reactions ranging from serum sickness to an allergy (such as hay fever) or, at the severest, to anaphylactic shock (see ANAPHYLAXIS). See also ALLERGY, IMMUNITY.
—hypersensitivity n.

Back  -    New Search

hypersplenism (hy-per-splen-izm) n.

a decrease in the numbers of red cells, white cells, and platelets in the blood resulting from destruction or pooling of these cells by an enlarged spleen.

Back  -    New Search

hypertension (hy-per-ten-shn) n.

high blood pressure, i.e. elevation of the arterial blood pressure above the normal range expected in a particular age group. Hypertension may be of unknown cause (essential h. or hyperpiesia ). It may also result from disease (secondary or symptomatic h. ), as of the kidneys (renal h. ), endocrine system, or arteries. Complications that may arise from hypertension include atherosclerosis, heart failure, cerebral haemorrhage, and kidney failure. Most cases of hypertension depend upon long-term drug therapy to lower the blood pressure and maintain it within the normal range. The drugs used include thiazide diuretics, beta blockers, methyldopa, and many others. See also PORTAL HYPERTENSION, PULMONARY (HYPERTENSION).

Back  -    New Search

hyperthermia (hyperthermy) (hy-per-therm-i) n.

1 exceptionally high body temperature (about 41°C or above). See FEVER.

2 treatment of disease by inducing fever. Compare HYPOTHERMIA.
Top

Back  -    New Search

hyperthyroidism (hy-per-th'y-roid-izm) n.

overactivity of the thyroid gland, either due to a tumour, overgrowth of the gland, or Graves's disease. See THYROTOXICOSIS.

Back  -    New Search

hypertonia (hypertonicity) (hy-per-toh-ni) n.

exceptionally high tension in muscles.

Back  -    New Search

hypertonic (hy-per-tonn-ik) adj.

1 describing a solution that has a greater osmotic pressure than another solution. See OSMOSIS.

2 describing muscles that demonstrate an abnormal increase in tonicity.
Top

Back  -    New Search

hypertrichosis (hy-per-trik-oh-sis) n.

excessive growth of hair.

Back  -    New Search

hypertrophy (hypertrophia) (hy-per-tr-fi) n.

increase in the size of a tissue or organ brought about by the enlargement of its cells rather than by cell multiplication. Compare HYPERPLASIA.

Back  -    New Search

hypertropia (hy-per-troh-pi) n.

strabismus in which one eye looks upwards.

Back  -    New Search

hyperuricaemia (lithaemia) (hy-per-yoor-i-see-mi) n.

the presence in the blood of an abnormally high concentration of uric acid. See GOUT.

Back  -    New Search

hyperuricuria (lithuria) (hy-per-yoor-ik-yoor-i) n.

the presence in the urine of an abnormally high concentration of uric acid.

Back  -    New Search

hyperventilation (hy-per-ven-ti-lay-shn) n.

breathing at an abnormally rapid rate at rest. This causes a reduction of the carbon dioxide concentration of the arterial blood, leading to dizziness, tingling in the lips and limbs, tetanic cramps in the hands, and tightness across the chest. h. syndrome prolonged hyperventilation, often of psychogenic origin, which may lead to loss of consciousness.

Back  -    New Search

hypervitaminosis (hy-per-vit--min-oh-sis) n.

the condition resulting from excessive consumption of vitamins. The fat-soluble vitamins A and D are toxic if taken in excessive amounts.

Back  -    New Search

hypervolaemia (hy-per-v-lee-mi) n.

an increase in the volume of circulating blood.

Back  -    New Search

hyphaema (hy-fee-m) n.

a collection of blood in the chamber of the eye that lies in front of the iris.

Back  -    New Search

hypn- (hypno-) prefix

denoting 1 sleep.

2 hypnosis.
Top

Back  -    New Search

hypnosis (hip-noh-sis) n.

a sleeplike state, artificially induced by a hypnotist , in which the mind is more than usually receptive to suggestion. Hypnotic suggestion has been used for a variety of purposes in medicine, for example as a cure for addiction and in other forms of psychotherapy.

Back  -    New Search

hypnotherapy (hip-noh-th'e-r-pi) n.

any form of psychotherapy that utilizes hypnosis.
—hypnotherapist n.

Back  -    New Search

hypnotic (soporific) (hip-not-ik) n.

a drug that produces sleep by depressing brain function. Hypnotics include benzodiazepines (e.g. nitrazepam, temazepam), chloral hydrate, and some sedative antihistamines (e.g. promethazine). They often cause hangover effects in the morning.

Back  -    New Search

hypnotism (hip-n-tizm) n.

the induction of hypnosis.

Back  -    New Search

hypo- prefix.

see HYP-.

Back  -    New Search

hypoaesthesia (hy-poh-ees-theez-i) n.

a condition in which the sense of touch is diminished. This may rarely be extended to include other forms of sensation.

Back  -    New Search

hypocalcaemia (hy-poh-kal-see-mi) n.

the presence in the blood of an abnormally low concentration of calcium. See TETANY. Compare HYPERCALCAEMIA.

Back  -    New Search

hypocapnia (hy-poh-kap-ni) n.

see ACAPNIA.

Back  -    New Search

hypochloraemia (hy-poh-klor-ee-mi) n.

the presence in the blood of an abnormally low concentration of chloride.

Back  -    New Search

hypochlorhydria (hy-poh-klor-hy-dri) n.

reduced secretion of hydrochloric acid by the stomach. See ACHLORHYDRIA.

Back  -    New Search

hypochlorite (hy-poh-klor-ryt) n.

any salt of hypochlorous acid (chloric(I) acid; HClO). Hypochlorites have antiseptic and disinfectant properties, e.g. Milton (sodium hypochlorite).

Back  -    New Search

hypochondria (hy-poh-kon-dri) n.

preoccupation with the physical functioning of the body and with fancied ill health. In the most severe form there are delusions of ill health, usually due to underlying depression.
—hypochondriac n. —hypochondriacal (hy-poh-kon-dry--kl) adj.

Back  -    New Search

hypochondriasis (hypochondriacal disorder (hy-poh-kon-dry--sis) n.

symptoms of hypochondria that have reached a level sufficient to be classified as a disorder.

Back  -    New Search

hypochondrium (hy-poh-kon-dri-m) n.

the upper lateral portion of the abdomen, situated beneath the lower ribs.
—hypochondriac adj.

Back  -    New Search

hypochromic (hy-poh-kroh-mik) adj.

1 deficient in pigmentation.

2 (of red blood cells) deficient in haemoglobin.
Top

Back  -    New Search

hypodermic (hy-poh-derm-ik) adj.

beneath the skin: usually applied to subcutaneous injections. The term is also applied to the syringe used for such injections.

Back  -    New Search

hypofibrinogenaemia (fibrinogenopenia) (hy-poh-fi-brin-oh-j-nee-mi) n.

a deficiency of the clotting factor fibrinogen in the blood, which results in an increased tendency to bleed. It may occur as an inherited disorder or it may be acquired.

Back  -    New Search

hypogammaglobulinaemia (hy-poh-gam--glob-yoo-lin-ee-mi) n.

a deficiency of the protein gammaglobulin in the blood, resulting in an increased susceptibility to infections. It may occur in a variety of inherited disorders or as an acquired defect.

Back  -    New Search

hypogastrium (hy-poh-gas-trim) n.

that part of the central abdomen situated below the region of the stomach.
—hypogastric adj.

Back  -    New Search

hypoglossal nerve (hy-poh-glos-l) n.

the twelfth cranial nerve (XII), which supplies the muscles of the tongue and is therefore responsible for the movements of talking and swallowing.

Back  -    New Search

hypoglycaemia (hy-poh-gly-see-mi) n.

a deficiency of glucose in the bloodstream, causing muscular weakness and incoordination, mental confusion, and sweating. If severe it may lead to hypoglycaemic coma . Hypoglycaemia most commonly occurs in diabetes mellitus. It is treated by administration of glucose.
—hypoglycaemic adj.

Back  -    New Search

hypohidrosis (hy-poh-hy-droh-sis) n.

a reduction in sweating in the presence of an appropriate stimulus for sweating (such as heat). It may accompany disease or occur as a congenital defect.

Back  -    New Search

hypoinsulinism (hy-poh-ins-yoo-lin-izm) n.

a deficiency of insulin due either to inadequate secretion of the hormone by the pancreas or to inadequate treatment of diabetes mellitus.

Back  -    New Search

hypokalaemia (hy-poh-kal-ee-mi) n.

the presence of abnormally low levels of potassium in the blood: occurs in dehydration. See ELECTROLYTE.

Back  -    New Search

hypomania (hy-poh-may-ni) n.

a mild degree of mania. Elated mood leads to faulty judgment; behaviour lacks the usual social restraints and the sexual drive is increased; speech is rapid and animated; the individual is energetic but not persistent and tends to be irritable.
—hypomanic (hy-poh-man-ik) adj., n.

Back  -    New Search

hypomenorrhoea (hy-poh-men--ree-) n.

the release of an abnormally small quantity of blood at menstruation.

Back  -    New Search

hypomotility (hy-poh-moh-til-iti) n.

decreased movement or activity, especially of the stomach or intestine.

Back  -    New Search

hyponatraemia (hy-poh-n-tree-mi) n.

the presence in the blood of an abnormally low concentration of sodium: occurs in dehydration. See ELECTROLYTE.

Back  -    New Search

hypoparathyroidism (hy-poh-pa-r-th'y-roid-izm) n.

subnormal activity of the parathyroid glands, causing a fall in the blood concentration of calcium and muscular spasms (see TETANY).

Back  -    New Search

hypopharynx (hy-poh-fa-rinks) n.

see LARYNGOPHARYNX.

Back  -    New Search

hypophysectomy (hy-pof-i-sek-tmi) n.

the surgical removal or destruction (by radiotherapy) of the pituitary gland (hypophysis) in the brain.

Back  -    New Search

hypophysis (hy-pof-i-sis) n.

see PITUITARY GLAND.

Back  -    New Search

hypopiesis (hy-poh-py-ee-sis) n.

abnormally reduced blood pressure (see HYPOTENSION) in the absence of organic disease.

Back  -    New Search

hypopituitarism (hy-poh-pit-yoo-it-er-izm) n.

subnormal activity of the pituitary gland, causing dwarfism in childhood and a syndrome of impaired sexual function, pallor, and premature ageing in adult life (see SIMMOND's DISEASE).

Back  -    New Search

hypoplasia (hy-poh-play-zi) n.

underdevelopment of an organ or tissue.

Back  -    New Search

hypoplastic left heart (hy-poh-plast-ik) n.

a congenital heart disorder in which the left side of the heart, particularly the left ventricle, is underdeveloped. Affected babies usually develop severe heart failure within the first few days of life. Most babies die within the first few weeks, but milder cases may be amenable to surgery.

Back  -    New Search

hypopnoea (hy-poh-nee-) n.

an abnormal decrease in the rate and depth of breathing.

Back  -    New Search

hypoproteinaemia (hy-poh-proh-ti-nee-mi) n.

a decrease in the quantity of protein in the blood, resulting in oedema and increased susceptibility to infections. It may result from malnutrition, impaired protein production, or increased loss of protein from the body. See also HYPOGAMMAGLOBULINAEMIA.

Back  -    New Search

hypoprothrombinaemia (hy-poh-proh-throm-bin-ee-mi) n.

a deficiency of the clotting factor prothrombin in the blood, which results in an increased tendency to bleed.

Back  -    New Search

hypopyon (hy-poh-pi-n) n.

pus in the chamber of the eye that lies in front of the iris.

Back  -    New Search

hyposecretion (hy-poh-si-kree-shn) n.

decreased secretion.

Back  -    New Search

hyposensitive (hy-poh-sen-si-tiv) adj.

less than normally responsive to the presence of antigenic material. Compare HYPERSENSITIVE.
—hyposensitivity n.

Back  -    New Search

hyposensitization (hy-poh-sen-si-ty-zay-shn) n.

see DESENSITIZATION.

Back  -    New Search

hypospadias (hy-poh-spay-di-s) n.

a congenital abnormality in which the opening of the urethra is on the underside of the penis: either on the glans penis (glandular h. ), at the junction of the glans with the shaft (coronal h. ), or on the shaft itself (penile h. ). See MAGPI OPERATION.

Back  -    New Search

hypostasis (hy-pos-t-sis) n.

accumulation of fluid or blood in a dependent part of the body in cases of poor circulation. Hypostatic pneumonia results from hypostatic congestion of the lung bases in debilitated patients who are confined to bed.
—hypostatic (hy-poh-stat-ik) adj.

Back  -    New Search

hyposthenia (hy-pos-th'ee-ni) n.

a state of physical weakness or abnormally low muscular tension.

Back  -    New Search

hypotension (hy-poh-ten-shn) n.

a condition in which the arterial blood pressure is abnormally low. It occurs after excessive fluid or blood loss. Other causes include myocardial infarction, pulmonary embolism, Addison's disease, severe infections, allergic reactions, arrhythmias, and acute abdominal conditions (e.g. pancreatitis). orthostatic h. temporary hypotension experienced when rising from a horizontal position.

Back  -    New Search

hypothalamus (hy-poh-thal--ms) n.

the region of the forebrain in the floor of the third ventricle, linked with the thalamus above and the pituitary gland below. It contains several important centres controlling body temperature, thirst, hunger, and eating, water balance, and sexual function. It also functions as a centre for the integration of hormonal and autonomic nervous activity.
—hypothalamic adj.

Back  -    New Search

hypothenar (hy-poth-i-nar) adj.

describing or relating to the fleshy prominent part of the palm of the hand below the little finger. Compare THENAR.

Back  -    New Search

hypothermia (hy-poh-therm-i) n.

1 accidental reduction of body temperature below the normal range. It is particularly liable to occur in babies and the elderly.

2 deliberate lowering of body temperature for therapeutic purposes. This may be done during surgery, in order to reduce the patient's requirement for oxygen.
Top

Back  -    New Search

hypothyroidism (hy-poh-th'y-roid-izm) n.

subnormal activity of the thyroid gland. If present at birth and untreated it leads to cretinism. In adult life it causes myxoedema. The condition can be treated by administration of thyroxine.

Back  -    New Search

hypotonia (hy-poh-toh-ni) n.

a state of reduced tension in muscle.

Back  -    New Search

hypotonic (hy-poh-tonn-ik) adj.

1 describing a solution that has a lower osmotic pressure than another solution. See OSMOSIS.

2 describing muscles that demonstrate diminished tonicity.
Top

Back  -    New Search

hypotrichosis (hy-poh-trik-oh-sis) n.

a condition in which less hair develops than normal.

Back  -    New Search

hypotropia (hy-poh-troh-pi) n.

strabismus in which one eye looks downwards.

Back  -    New Search

hypoventilation (hy-poh-ven-ti-lay-shn) n.

breathing at an abnormally shallow and slow rate, which results in an increased concentration of carbon dioxide in the blood.

Back  -    New Search

hypovitaminosis (hy-poh-vit--min-oh-sis) n.

a deficiency of a vitamin caused either through lack of the vitamin in the diet or from an inability to absorb or utilize it.

Back  -    New Search

hypovolaemia (oligaemia) (hy-poh-v-lee-mi) n.

a decrease in the volume of circulating blood. See SHOCK.

Back  -    New Search

hypoxaemia (hy-poks-ee-mi) n.

reduction of the oxygen concentration in the arterial blood, recognized clinically by the presence of central and peripheral cyanosis.

Back  -    New Search

hypoxia (hy-poks-i) n.

a deficiency of oxygen in the tissues. See also ANOXIA, HYPOXAEMIA.

Back  -    New Search

hyster- (hystero-) prefix

denoting 1 the uterus.

2 hysteria.
Top

Back  -    New Search

hysterectomy (hiss-ter-ek-tmi) n.

the surgical removal of the uterus, either through an incision in the abdominal wall (abdominal h. ) or through the vagina (vaginal h. ). subtotal h. removal of the body of the uterus, leaving the neck (cervix) in place. total h. removal of the entire uterus. See also WERTHEIM'S HYSTERECTOMY.

Back  -    New Search

hysteria (hiss-teer-i) n.

1 formerly, a neurosis whose principal features consist of emotional instability, repression, dissociation, physical symptoms, and vulnerability to suggestion. conversion h. see CONVERSION DISORDER. dissociative h. see DISSOCIATIVE DISORDER.

2 a state of great emotional excitement.
Top

Back  -    New Search

hysterical (hiss-te-ri-kl) adj.

1 describing symptoms characteristic of conversion disorder.

2 describing a kind of personality disorder characterized by instability and shallowness of feelings.
Top

Back  -    New Search

hysteroptosis (hiss-ter-op-toh-sis) n.

prolapse of the uterus. See PROLAPSE.

Back  -    New Search

hysterosalpingography (hiss-ter-oh-sal-ping-og-rfi) n.

see UTEROSALPINGOGRAPHY.

Back  -    New Search

hysterosalpingosonography (hiss-ter-oh-sal-ping-oh-sonn-og-rfi) n.

visualization of the Fallopian tubes by means of an ultrasound beam, usually directed via a vaginal probe, after a contrast medium has been passed through them via the cervix. See also (TRANSVAGINAL) ULTRASONOGRAPHY.

Back  -    New Search

hysteroscope (uteroscope) (hiss-ter-oh-skohp) n.

a tubular instrument with a light source for observing the interior of the uterus. See also ENDOSCOPE.

Back  -    New Search

hysterotomy (hiss-ter-ot-mi) n.

an operation for removal of the fetus by incision of the uterus through the abdomen before the 24th week of gestation; after this time the operation is called Caesarean section. Hysterotomy is now rarely performed.

Back  -    New Search

hysterotrachelorrhaphy (hiss-ter-oh-trak-el-o-rfi) n.

the operation of stitching a tear in the cervix of the uterus.

Back  -    New Search

I

-iasis suffix

denoting a diseased condition.

Back  -    New Search

iatro- prefix

denoting
1 medicine.
2 doctors.

Back  -    New Search

iatrogenic (I-at-roh-jen-ik) adj.

describing a condition that has resulted from treatment, as either an unforeseen or inevitable side-effect.

Back  -    New Search

IBD n.

see INFLAMMATORY BOWEL DISEASE.

Back  -    New Search

IBS n.

see IRRITABLE BOWEL SYNDROME.

Back  -    New Search

ibuprofen (I-bew-proh-fen) n.

an anti-inflammatory drug (see NSAID), administered by mouth in the treatment of arthritic conditions. Trade names: Brufen , Junifen .

Back  -    New Search

ICD n.

see INTERNATIONAL CLASSIFICATION OF DISEASES. ICD-10 the latest version, published in 1992.

Back  -    New Search

ichor (I-kor) n.

a watery material oozing from wounds or ulcers.

Back  -    New Search

ichthammol (ik-tham-ol) n.

a sulphur-containing drug with antibacterial properties, used in the form of an ointment for treating certain skin diseases.

Back  -    New Search

ichthyosis (ik-thi-oh-sis) n.

any one of a group of genetically determined skin disorders in which there is abnormal scaling of the skin. Xeroderma is a very mild form of the disorder. i. vulgaris the most common form of the disease, which is inherited as an autosomal dominant condition.

Back  -    New Search

ICSH (interstitial-cell-stimulating hormone) n.

see LUTEINIZING HORMONE.

Back  -    New Search

ICSI (ik-si) n.

intracytoplasmic sperm injection: a technique of assisted conception in some cases of male infertility in which a single spermatozoon is injected into the cytoplasm of an ovum in vitro. The fertilized ovum is then implanted into the uterus.

Back  -    New Search

icterus (ik-ter-s) n.

see JAUNDICE.

Back  -    New Search

ictus (ik-ts) n.

a stroke or any sudden attack. The term is often used for an epileptic seizure.

Back  -    New Search

id (id) n.

(in psychoanalysis) a part of the unconscious mind governed by the instinctive forces of libido and the death wish.

Back  -    New Search

-id suffix

denoting relationship or resemblance to.

Back  -    New Search

ideation (I-di-ay-shn) n.

the process of thinking or of having imagery or ideas.

Back  -    New Search

identical twins (I-den-tik-l) pl. n.

see TWINS.

Back  -    New Search

identification (I-den-ti-fi-kay-shn) n.

(in psychological development) the process of adopting other people's characteristics more or less permanently. Identification with a parent is important in personality formation.

Back  -    New Search

ideo- prefix

denoting
1 the mind or mental activity.
2 ideas.

Back  -    New Search

ideomotor (I-di--moh-ter) adj.

describing or relating to a motor action that is evoked by an idea. i. apraxia the inability to translate the idea of a complex behaviour into action.

Back  -    New Search

idio- prefix

denoting peculiarity to the individual.

Back  -    New Search

idiopathic (idi-oh-path-ik) adj.

denoting a disease or condition the cause of which is not known or that arises spontaneously. i. thrombocytopenic purpura see PURPURA.
—idiopathy (idi-op--thi) n.

Back  -    New Search

idiosyncrasy (idi-oh-sink-rsi) n.

an unusual and unexpected sensitivity exhibited by an individual to a particular drug or food.
—idiosyncratic (idi-oh-sin-krat-ik) adj.

Back  -    New Search

idiot savant (eed-yoh sa-vahn) n.

an individual whose overall functioning is at the level of mental retardation but who has one or more special intellectual abilities that are advanced to a high level.

Back  -    New Search

idioventricular (idi-oh-ven-trik-yoo-ler) adj.

affecting or peculiar to the ventricles of the heart. i. rhythm the very slow beat of the ventricles under the influence of their own natural subsidiary pacemaker.

Back  -    New Search

idoxuridine (I-doks-yoor-i-deen) n.

an iodine-containing drug that inhibits the growth of viruses and is administered in eye drops or ointment to treat viral infections of the eye. Trade names: Herpid , Idoxene .

Back  -    New Search

ifosfamide (I-fos-f-myd) n.

a cytotoxic drug used in the treatment of malignant disease, particularly sarcomas, testicular tumours, and lymphomas. It is administered intravenously by injection or infusion. Trade name: Mitoxana .

Back  -    New Search

IL-2 n.

see INTERLEUKIN.

Back  -    New Search

ile- (ileo-) prefix

denoting the ileum.

Back  -    New Search

ileal conduit (il-i-l) n.

a segment of small intestine (ileum) used to convey urine from the ureters to the exterior into an appliance (see also URINARY DIVERSION). The ureters are implanted into an isolated segment of bowel, one end of which is brought through the abdominal wall to the skin surface.

Back  -    New Search

ileal pouch (perineal pouch) n.

a reservoir made from loops of ileum to replace a surgically removed rectum, avoiding the need for a permanent ileostomy.

Back  -    New Search

ileectomy (ili-ek-tmi) n.

surgical removal of the ileum or part of the ileum.

Back  -    New Search

ileitis (ili-l-tis) n.

inflammation of the ileum. It may be caused by Crohn's disease, tuberculosis, the bacterium Yersinia enterocolitica, or typhoid or it may occur in association with ulcerative colitis.

Back  -    New Search

ileocaecal (ili-oh-see-kl) adj.

relating to the ileum and caecum. i. valve a valve at the junction of the small and large intestines consisting of two membranous folds that close to prevent the backflow of food from the colon and caecum to the ileum.

Back  -    New Search

ileocaecocystoplasty (ili-oh-see-koh-sis-toh-plasti) n.

an operation in which the dome of the bladder is removed by cutting across the bladder transversely above the openings of the ureters; the dome is replaced by an isolated segment of caecum and terminal ileum. See CYSTOPLASTY.

Back  -    New Search

ileocolitis (ili-oh-k-ly-tis) n.

inflammation of the ileum and the colon. The commonest causes are Crohn's disease and tuberculosis.

Back  -    New Search

ileocolostomy (ili-oh-k-lost-mi) n.

a surgical operation in which the ileum is joined to some part of the colon.

Back  -    New Search

ileocystoplasty (ili-oh-sis-toh-plasti) n.

an operation in which the bladder is enlarged by an opened-out portion of small intestine. See CYSTOPLASTY.

Back  -    New Search

ileoproctostomy (ili-oh-prok-tost-mi) n.

see ILEORECTAL (ANASTOMOSIS).

Back  -    New Search

ileorectal (ili-oh-rek-t'l) adj.

relating to the ileum and rectum. i. anastomosis (ileoproctostomy) a surgical operation in which the ileum is joined to the rectum, usually after surgical removal of the colon (see COLECTOMY).

Back  -    New Search

ileosigmoidostomy (ili-oh-sig-moid-ost-mi) n.

an operation in which an opening is created between the ileum and the sigmoid colon.

Back  -    New Search

ileostomy (ili-ost-mi) n.

a surgical operation in which the ileum is brought through the abdominal wall to create an artificial opening (stoma ) through which the intestinal contents can discharge, thus bypassing the colon. Various types of bag may be worn to collect the effluent.

Back  -    New Search

ileum (il-im) n.

the lowest of the three portions of the small intestine (see INTESTINE). It runs from the jejunum to the ileocaecal valve.
—ileal, ileac adj.

Back  -    New Search

ileus (il-i-s) n.

intestinal obstruction, usually obstruction of the small intestine (ileum). paralytic or adynamic i. functional obstruction of the ileum due to loss of peristalsis, which may be caused by abdominal surgery, spinal injuries, hypokalaemia, or peritonitis. Treatment consists of intravenous administration of fluid and nutrients and removal of excess stomach secretions by tube until peristalsis returns.

Back  -    New Search

ili- (ilio-) prefix

denoting the ilium.

Back  -    New Search

iliac (il-i-ak) adj.

relating to the ilium. i. arteries the arteries that supply most of the blood to the lower limbs and pelvic region. i. fossa a concave depression on the inside of the pelvis. The right iliac fossa provides space for the vermiform appendix. i. veins the veins draining most of the blood from the lower limbs and pelvic region.

Back  -    New Search

iliacus (i-lee--ks) n.

a flat triangular muscle situated in the area of the groin. This muscle acts in conjunction with the psoas muscle to flex the thigh.

Back  -    New Search

iliococcygeal (ili-oh-kok-sij-il) adj.

relating to the ilium and the coccyx.

Back  -    New Search

iliopsoas (ili-oh-soh-s) n.

a composite muscle made up of the iliacus and psoas muscles, which have a common tendon.

Back  -    New Search

ilium (il-im) n.

the haunch bone: a wide bone forming the upper part of each side of the hip bone (see also PELVIS).
—iliac adj.

Back  -    New Search

illusion (i-loo-zhn) n.

a false perception due to misinterpretation of the stimuli arising from an object. Illusions may occur in almost any psychiatric syndrome, especially depression. Compare HALLUCINATION. optical i. a perception that does not agree with the actual object in the external world. Optical illusions are produced by deceptive qualities of the stimulus and are in no way pathological.

Back  -    New Search

image (im-ij) n.

1 (in physiology) an optical reproduction of an object formed on the retina when light is refracted through the eye.

2 (in psychology) a mental representation resulting from thought rather than from sensory perception. See BODY IMAGE, IMAGERY.
Top

Back  -    New Search

imagery (im-ij-er-i) n.

the production of vivid mental representations by the normal processes of thought. eidetic i. the production of images of exceptional clarity, which may be recalled long after being first experienced.

Back  -    New Search

imaging (im-ij-ing) n.

the production of images of organs or tissues using radiological procedures, particularly by using scanning techniques. See also COMPUTERIZED TOMOGRAPHY (CT), MAGNETIC RESONANCE IMAGING (MRI), REAL-TIME IMAGING, ULTRASONOGRAPHY.

Back  -    New Search

imago (i-may-goh) n.

(in psychoanalysis) the internal unconscious representation of an important person in the individual's life, particularly a parent.

Back  -    New Search

imidazole (i-mid--zohl) n.

one of a group of chemically related antifungal drugs that are also effective against a wide range of bacteria; some (e.g. thiabendazole and mebendazole) are also used as anthelmintics. The group includes econazole, clotrimazole, ketoconazole, and miconazole.

Back  -    New Search

imipramine (i-mip-r-meen) n.

a drug administered by mouth or injection to treat depression (see ANTIDEPRESSANT). Trade name: Tofranil .

Back  -    New Search

immersion foot (i-mer-shn) n.

see TRENCH FOOT.

Back  -    New Search

immiscible (i-mis-ibl) adj.

incapable of being mixed to form a homogeneous substance. Oil and water are immiscible.

Back  -    New Search

immobilization (i-moh-bi-ly-zay-shn) n.

the procedure of making a normally movable part of the body, such as a joint, immovable. This helps an infected, diseased, or injured tissue (bone, joint, or muscle) to heal.

Back  -    New Search

immune (i-mewn) adj.

protected against a particular infection by the presence of specific antibodies against the organisms concerned. i. response the reaction of the body to the presence of antigens (foreign tissues, bacteria, etc.), which are attacked and destroyed by antibodies. See ANTIBODY, ANTIGEN, IMMUNITY. i. system the organs and tissues responsible for immunity, including the thymus, bone marrow, lymph nodes, spleen, and tonsils. See also LYMPHOID TISSUE.

Back  -    New Search

immunity (i-mewn-iti) n.

the body's ability to resist infection, afforded by the presence of circulating antibodies and white blood cells. active i. immunity that arises when the body's own cells produce, and remain able to produce, appropriate antibodies following an attack of a disease or deliberate stimulation (see IMMUNIZATION). cell-mediated i. immunity resulting from the action of antibodies bound to the surface of lymphocytes. humoral i. immunity resulting from the action of circulating antibodies. passive i. temporary immunity that may be provided by injecting ready-made antibodies in antiserum taken from another person or an animal already immune. Babies have passive immunity, conferred by antibodies from the maternal blood and colostrum, to common diseases for several weeks after birth.

Back  -    New Search

immunization (im-yoo-ny-zay-shn) n.

the production of immunity by artificial means. Passive immunity may be conferred by the injection of an antiserum, but the production of active immunity calls for the use of a vaccine (see VACCINATION).

Back  -    New Search

immuno- prefix

denoting immunity or immunological response.

Back  -    New Search

immunoassay (im-yoo-noh-ass-ay) n.

any of various techniques for determining the levels of antigen and antibody in a tissue. See RADIOIMMUNOASSAY.

Back  -    New Search

immunocompromised (im-yoo-noh-kom-pr-myzd) adj.

describing patients in whom the immune response is reduced or defective due to immunosuppression. Such patients are vulnerable to opportunistic infections.

Back  -    New Search

immunodeficiency (im-yoo-noh-di-fish-n-si) n.

deficiency in the immune response. This can be acquired, as in AIDS, but there are many varieties of primary immunodeficiency occurring as inherited disorders characterized by hypogammaglobulinaemia.

Back  -    New Search

immunogenicity (im-yoo-noh-jn-iss-iti) n.

the property that enables a substance to provoke an immune response, including foreignness (see ANTIGEN), size, route of entry into the body, dose, number and length of exposures to the antigen, and host genetic make-up.

Back  -    New Search

immunoglobulin (lg) (im-yoo-noh-glob-yoo-lin) n.

one of a group of structurally related proteins (gamma globulins) that act as antibodies.

Back  -    New Search

immunological tolerance (im-yoo-n-loj-ik-l) n.

a failure of the body to distinguish between materials that are ‘self’, and therefore to be tolerated, and those that are ‘not self’, against which antibodies should be produced.

Back  -    New Search

immunology (im-yoo-nol-ji) n.

the study of immunity and all of the phenomena connected with the defence mechanisms of the body.
—immunological adj.

Back  -    New Search

immunophoresis (im-yoo-noh-fer-ee-sis) n.

a technique, relying upon the precipitin reaction, for identifying an unknown antigen or testing for an antibody in a serum.

Back  -    New Search

immunosuppression (im-yoo-noh-s-presh-n) n.

suppression of the immune response, usually by disease (e.g. AIDS) or by drugs (e.g. steroids, azathioprine, cyclosporin A).
—immunosuppressed adj.

Back  -    New Search

immunosuppressive (im-yoo-noh-s-pres-iv) n.

a drug, such as azathioprine, mustine, or cyclophosphamide, that reduces the body's resistance to infection and other foreign bodies by suppressing the immune system. Immunosuppressives are used to maintain the survival of organ and tissue transplants and to treat various autoimmune diseases. Cyclosporin A is the immunosuppressive usually used in organ transplant recipients.

Back  -    New Search

immunotherapy (im-yoo-noh-th'e-r-pi) n.

the prevention or treatment of disease using agents that may modify the immune response. It is a largely experimental approach, studied most widely in the treatment of cancer.

Back  -    New Search

immunotoxin (im-yoo-noh-toks-in) n.

one of a new class of drugs undergoing clinical trials for the treatment of leukaemia. Immunotoxins combine monoclonal antibodies, which specifically target cancerous cells, with a highly toxic compound (such as ricin) that inhibits protein synthesis.

Back  -    New Search

immunotransfusion (im-yoo-noh-trans-few-zhn) n.

the transfusion of an antiserum to treat or give temporary protection against a disease.

Back  -    New Search

impacted (im-pak-tid) adj.

firmly wedged. i. faeces faeces that are so hard and dry that they cannot pass through the anus and require manual removal under an anaesthetic. i. fracture see FRACTURE. i. tooth a tooth, usually a wisdom tooth, that cannot erupt into a normal position because it is obstructed by other tissues.
—impaction n.

Back  -    New Search

impairment (im-pair-mnt) n.

see HANDICAP.

Back  -    New Search

impalpable (im-palp-bl) adj.

describing a structure within the body that cannot be detected by feeling with the hand.

Back  -    New Search

imperforate (im-per-fer-it) adj.

lacking an opening. i. anus (proctatresia) partial or complete obstruction of the anus: a condition, discovered at birth, due to failure of the anus to develop normally in the embryo. Most mild cases of imperforate anus can be treated by a simple operation. i. hymen a condition in which the hymen completely closes the vagina and thus impedes the flow of menstrual blood.

Back  -    New Search

impetigo (imp-i-ty-goh) n.

a superficial bacterial infection of the skin, which usually responds to treatment with antibiotics. bullous i. impetigo caused by Staphylococcus aureus. It is characterized by blisters, is less contagious than the nonbullous form, and occurs at any age. nonbullous i. impetigo caused by Staphylococcus aureus, Streptococcus species, or both organisms; it mainly affects young children and is highly contagious, with yellowish-brown crusting.

Back  -    New Search

implant (im-plahnt) n.

a drug (such as a subcutaneous hormone implant), a prosthesis (such as an artificial hip), or a radioactive source (such as radium needles) that is put into the body. breast i. a prosthesis inserted subcutaneously to replace breast tissue that has been removed surgically during a simple mastectomy in the treatment of breast cancer or to augment existing breast tissue. The type of implant in current use is a silicone sac filled with silicone gel. dental i. a rigid structure that is embedded in the jawbone or under its periosteum to provide support for replacement teeth on a denture or a bridge. heart i. see ARTIFICIAL HEART. intraocular lens i. a plastic lens placed inside the eye after cataract surgery. osseointegrated i. an implant that can be introduced into living bone without producing a foreign-body reaction (see OSSEOINTEGRATION). See also COCHLEAR IMPLANT.

Back  -    New Search

implantation (im-plahn-tay-shn) n.

1 (or nidation) the attachment of the early embryo to the lining of the uterus, which occurs six to eight days after ovulation
.
2 the placing of a substance (e.g. a drug) or an object (e.g. an artificial pacemaker) within a tissue
Top
.
3 the surgical replacement of damaged tissue with healthy tissue (see TRANSPLANTATION).
Top

Back  -    New Search

implementation (im-pli-men-tay-shn) n.

the stage of the nursing process in which the patient's individual care plan is utilized and executed, in collaboration with other members of the health-care team.

Back  -    New Search

implosion (im-ploh-zhn) n.

see FLOODING.

Back  -    New Search

impotence (im-p-tns) n.

inability in a man to have sexual intercourse. Impotence may be erectile , in which the penis does not become firm enough to enter the vagina, or ejaculatory , in which penetration occurs but there is no ejaculation of semen (orgasm).

Back  -    New Search

impregnate (im-preg-nayt) vb.

1 to make pregnant.

2 to saturate with another substance.
Top

—impregnation n.

Back  -    New Search

impression (im-presh-n) n.

(in dentistry) a mould made of the teeth and surrounding soft tissues or of a toothless jaw. An impression is used in the construction of orthodontic appliances, restorations, and dentures.

Back  -    New Search

impulse (im-puls) n.

(in neurology) see NERVE IMPULSE.

Back  -    New Search

in- (im-) prefix

denoting
1 not.
2 in; within; into.

Back  -    New Search

inaccessible (in-ak-ses-ibl) adj.

(in psychiatry) unresponsive to words and similar stimuli: describing the mental state of certain patients, e.g. schizophrenics.
—inaccessibility n.

Back  -    New Search

inanition (in--nish-n) n.

a condition of exhaustion caused by lack of nutrients in the blood. This may arise through starvation, malnutrition, or intestinal disease.

Back  -    New Search

in articulo mortis (in ar-tik-yoo-loh mor-tis)

Latin: at the moment of death.

Back  -    New Search

inborn error of metabolism (in-born e-rer) n.

any one of a group of inherited conditions in which there is a disturbance in either the structure, synthesis, function, or transport of protein molecules. Examples are phenylketonuria, homocystinuria, and hypogammaglobulinaemia.

Back  -    New Search

inbreeding (in-breed-ing) n.

the production of offspring by parents who are closely related. Compare OUTBREEDING.

Back  -    New Search

incarcerated (in-kar-ser-ayt-id) adj.

confined or constricted so as to be immovable: applied particularly to a type of hernia.

Back  -    New Search

incest (in-sest) n.

sexual intercourse between close relatives, e.g. brother and sister or father and daughter.

Back  -    New Search

incipient (in-sip-int) adj.

coming into existence: describing a stage in a disease.

Back  -    New Search

incision (in-sizh-n) n.

1 the surgical cutting of soft tissues, such as skin or muscle, with a knife or scalpel.

2 the cut so made.
Top

Back  -    New Search

incisor (in-sy-zer) n.

any of the four front teeth in each jaw, two on each side of the midline. See also DENTITION.

Back  -    New Search

inclusion bodies (in-kloo-zhn) pl. n.

particles occurring in the nucleus and cytoplasm of cells usually as a result of virus infection. Their presence can sometimes be used to diagnose such an infection.

Back  -    New Search

inclusion conjunctivitis n.

see CONJUNCTIVITIS.

Back  -    New Search

incompatibility (in-km-pat-i-bil-iti) n.

lack of compatibility. In cases of severe incompatibility, there are likely to be swift immune reactions to transplanted organs or tissues.

Back  -    New Search

incompetence (in-kom-pi-tns) n.

impaired function of the valves of the heart or veins, which allows backward leakage of blood. See AORTIC REGURGITATION, MITRAL INCOMPETENCE, VARICOSE VEINS.

Back  -    New Search

incontinence (in-kon-ti-nns) n.

1 the inappropriate involuntary passage of urine. genuine stress i. (GSI) incontinence in women for which a physical cause can be identified. stress i. the leak of urine on coughing and straining. It is common in women in whom the muscles of the pelvic floor are weakened after childbirth. overflow i. leakage from a full bladder, which occurs most commonly in elderly men with bladder outflow obstruction. urge i. leakage of urine that accompanies an intense desire to pass water with failure of restraint. See also ENURESIS.

2 inability to control bowel movements (faecal i. ).
Top

Back  -    New Search

incoordination (in-koh-or-din-ay-shn) n.

(in neurology) an impairment in the performance of precise movements. Incoordination may result from a disorder in any part of the nervous system. See APRAXIA, ATAXIA, DYSSYNERGIA.

Back  -    New Search

incubation (in-kew-bay-shn) n.

1 the process of development of an egg or a culture of bacteria.

2 the care of a premature baby in an incubator.
Top

Back  -    New Search

incubation period (latent period) n.

the interval between exposure to an infection and the appearance of the first symptoms.

Back  -    New Search

incubator (ink-yoo-bay-ter) n.

a transparent container for keeping premature babies in controlled conditions and protecting them from infection. Other forms of incubator are used for cultivating bacteria and for hatching eggs.

Back  -    New Search

incus (ink-s) n.

a small anvil-shaped bone in the middle ear that articulates with the malleus and the stapes. See OSSICLE.

Back  -    New Search

independent nursing function (indi-pend-nt) n.

any aspect of nursing practice for which the nurse alone is responsible, acting on her own initiative and without instructions from any other discipline.

Back  -    New Search

Inderal (in-der-al) n.

see PROPRANOLOL.

Back  -    New Search

indican (in-di-kn) n.

a compound excreted in the urine as a detoxification product of indoxyl.

Back  -    New Search

indicanuria (in-di-kn-yoor-i) n.

the presence in the urine of an abnormally high concentration of indican. This may be a sign that the intestine is obstructed.

Back  -    New Search

indication (indi-kay-shn) n.

(in medicine) a strong reason for believing that a particular course of action is desirable. Compare CONTRAINDICATION.

Back  -    New Search

indigenous (in-dij-in-s) adj.

occurring naturally in a particular area, region, or country. Certain diseases are indigenous to particular regions.

Back  -    New Search

indigestion (indi-jes-chn) n.

see DYSPEPSIA.

Back  -    New Search

indigo carmine (in-dig-oh kar-myn) n.

a blue dye that is administered by injection to test for kidney function.

Back  -    New Search

individualized nursing care (indi-vid-yoo--lyzd) n.

care that is planned to meet the particular needs of one patient, as opposed to a routine applied to all patients suffering from the same disease.

Back  -    New Search

indole (in-dohl) n.

a derivative of the amino acid tryptophan, excreted in the urine and faeces.

Back  -    New Search

indolent (in-dl-nt) adj.

describing a disease process that is failing to heal or has persisted. The term is applied particularly to ulcers of skin or mucous membrane.

Back  -    New Search

indomethacin (in-doh-meth--sin) n.

an anti-inflammatory drug (see NSAID), administered by mouth or in suppositories in the treatment of arthritic conditions. Trade names: Indocid , Indomod .

Back  -    New Search

indoramin (in-dor--min) n.

an alpha blocker drug used to treat high blood pressure. It is administered by mouth. Trade names: Baratol , Doralese .

Back  -    New Search

indoxyl (in-doks-il) n.

an alcohol derived from indole by bacterial action. It is excreted in the urine as indican.

Back  -    New Search

induction (in-duk-shn) n.

1 (in obstetrics) the artificial starting of childbirth, e.g. by injecting oxytocin or puncturing the amnion, when pregnancy has continued considerably beyond the expected date of birth or if there is a risk to the health of mother or infant.

2 (in anaesthetics) initiation of anaesthesia. General anaesthesia is usually induced by injecting certain drugs, usually barbiturates, into the bloodstream.
Top

Back  -    New Search

induration (in-dewr-ay-shn) n.

abnormal hardening of a tissue or organ. See also SCLEROSIS.

Back  -    New Search

industrial disease (in-dus-tri-l) n.

an occupational disease associated with a particular industry or group of industries.

Back  -    New Search

inertia (in-er-sh) n.

(in physiology) sluggishness or absence of activity in certain smooth muscles. uterine i. inertia of the muscular wall of the uterus during labour, making the process excessively long. It may be present from the start of labour or it may develop because of exhaustion following strong contractions.

Back  -    New Search

in extremis (in iks-tree-mis)

Latin: at the point of death.

Back  -    New Search

infant (in-fnt) n.

a child incapable of any form of independence from its mother: usually, a child under one year of age, especially a newborn child. i. mortality rate the number of deaths of infants per 1000 live births in a given year. Included are the neonatal mortality rate (calculated from deaths occurring in the first four weeks of life) and postneonatal mortality rate (from deaths in the remainder of the first year).

Back  -    New Search

infanticide (in-fant-i-syd) n.

(in Britain) under the terms of the Infanticide Act 1938, the felony of child destruction by the natural mother within 12 months of birth when the balance of her mind is disturbed because she has not fully recovered from childbirth and/or lactation.

Back  -    New Search

infantile (in-fn-tyl) adj.

1 denoting conditions occurring in adults that are recognizable in childhood, e.g. poliomyelitis (i. paralysis ).

2 of, relating to, or affecting infants. i. spasms (salaam attacks ) a rare but serious form of epilepsy that usually begins between three and eight months of age. It is characterized by involuntary flexing movements of the arms, legs, neck, and trunk. It may be arrested by treatment with corticosteroids or ACTH.
Top

Back  -    New Search

infantilism (in-fant-il-izm) n.

persistence of childlike physical or psychological characteristics into adult life.

Back  -    New Search

infarct (in-farkt) n.

a small localized area of dead tissue produced as a result of an inadequate blood supply.

Back  -    New Search

infarction (in-fark-shn) n.

the death of part or the whole of an organ that occurs when the artery carrying its blood supply is obstructed by a blood clot (thrombus) or an embolus. See also MYOCARDIAL INFARCTION.

Back  -    New Search

infection (in-fek-shn) n.

invasion of the body by harmful organisms (pathogens), such as bacteria, fungi, protozoa, rickettsiae, or viruses. The infective agent may be transmitted by a patient or carrier in airborne droplets or by direct contact; by animal or insect vectors; by ingestion of contaminated food or drink; or from an infected mother to the fetus. After an incubation period symptoms appear, usually consisting of either localized inflammation and pain or more remote effects. Treatment with drugs is usually effective against most infections, but there is no specific treatment for many common viral infections.

Back  -    New Search

infectious disease (in-fek-shs) n.

see COMMUNICABLE DISEASE.

Back  -    New Search

infectious mononucleosis n.

see GLANDULAR FEVER.

Back  -    New Search

inferior (in-feer-i-er) adj.

(in anatomy) lower in the body in relation to another structure or surface.

Back  -    New Search

inferiority complex (in-feer-i-o-riti) n.

1 an unconscious exaggeration of feelings of inferiority, which is shown by compensatory behaviour, such as aggression.

2 (in psychoanalysis) a complex said to result from the conflict between Oedipal wishes (see OEDIPUS COMPLEX) and the reality of the child's lack of power. This gives rise to repressed feelings of personal inferiority.
Top

Back  -    New Search

infertility (in-fer-til-iti) n.

inability in a woman to conceive or in a man to induce conception. See also STERILITY.

Back  -    New Search

infestation (in-fes-tay-shn) n.

the presence of animal parasites either on the skin or inside the body.

Back  -    New Search

infibulation (in-fib-yoo-lay-shn) n.

the most extensive form of female circumcision, involving excision of the clitoris, labia minora, and labia majora.

Back  -    New Search

infiltration (in-fil-tray-shn) n.

1 the abnormal entry of a substance (infiltrate ) into a cell, tissue, or organ. Examples of infiltrates are blood cells, cancer cells, fat, or starch.

2 the injection of a local anaesthetic solution into the tissues to cause local anaesthesia.
Top

Back  -    New Search

inflammation (in-fl-may-shn) n.

the body's response to injury. acute i. the immediate defensive reaction of tissue to injury, which may be caused by infection, chemicals, or physical agents. It involves pain, heat, redness, swelling, and loss of function of the affected part. chronic i. the response that ensues when acute inflammation does not heal.
—inflammatory (in-flam--ter-i) adj.

Back  -    New Search

inflammatory bowel disease (IBD) n.

any of a group of inflammatory conditions of the intestine that include (among others) ulcerative colitis and Crohn's disease.

Back  -    New Search

influenza (in-floo-en-z) n.

a highly contagious virus infection that affects the respiratory system. Symptoms include headache, fever, loss of appetite, weakness, and general aches and pains. With bed rest and aspirin most patients recover, but a few go on to develop viral or bacterial pneumonia.

Back  -    New Search

informed consent (in-formd) n.

a legal requirement that physicians or researchers inform a patient undergoing surgery or invasive tests or a subject involved in a clinical trial of the nature, risks, and probable outcome of the treatment or research. The patient signs an agreement stating that he or she has been informed and accepts the treatment, surgery, or research protocol. Without informed consent, the physician or researcher is violating the patient's rights, regardless of whether the treatment is appropriate and successful.

Back  -    New Search

infra- prefix

denoting below.

Back  -    New Search

infrared radiation (in-fr-red) n.

the band of electromagnetic radiation that is longer in wavelength than the red of the visible spectrum and is responsible for the transmission of radiant heat. It may be used in physiotherapy to warm tissues, reduce pain, and improve circulation.

Back  -    New Search

infundibulum (in-fun-dib-yoo-lm) n.

any funnel-shaped channel or passage, particularly the hollow conical stalk that extends downwards from the hypothalamus and is continuous with the posterior lobe of the pituitary gland.

Back  -    New Search

infusion (in-few-zhn) n.

1 the slow injection of a substance, usually into a vein (intravenous i. ). This is a common method for replacing water, electrolytes, and blood products and is also used for the continuous administration of drugs or nutrition. See also DRIP.

2 the process whereby the active principles are extracted from plant material by steeping it in boiling water (as in the making of tea).
Top

3 the solution produced by this process.
Top

Back  -    New Search

ingesta (in-jes-t) pl. n.

food and drink that is taken into the alimentary canal through the mouth.

Back  -    New Search

ingestion (in-jes-chn) n.

the process by which food is taken into the alimentary canal. It involves chewing and swallowing.

Back  -    New Search

ingrowing toenail (in-groh-ing) n.

a toenail whose free margin grows or is pressed into the skin at the side of the nail, causing inflammation.

Back  -    New Search

inguinal (ing-win-l) adj.

relating to or affecting the region of the groin (inguen). i. canal either of a pair of openings that connect the abdominal cavity with the scrotum in the male fetus. i. hernia see HERNIA. i. ligament (Poupart's ligament ) a ligament in the groin that extends from the anterior superior iliac spine to the pubic tubercle. It is part of the aponeurosis of the external oblique muscle of the abdomen.

Back  -    New Search

INH n.

see ISONIAZID.

Back  -    New Search

inhalation (in-h-lay-shn) n.

1 (or inspiration) the act of breathing air into the lungs through the mouth and nose. See BREATHING.

2 a gas, vapour, or aerosol breathed in for the treatment of conditions of the respiratory tract.
Top

Back  -    New Search

inhaler (in-hay-ler) n.

a device for the administration of inhalations. metered-dose i. an inhaler designed to deliver the correct dose of an inhalation to the appropriate section of the airway.

Back  -    New Search

inherent (in-heer-nt) adj.

inborn; innate.

Back  -    New Search

inhibition (in-hib-ish-n) n.

1 (in physiology) the prevention or reduction of the functioning of an organ, muscle, etc., by the action of certain nerve impulses.

2 (in psychoanalysis) an inner command that prevents one from doing something forbidden
Top
.
3 (in psychology) a tendency not to carry out a specific action, produced each time the action is carried out.
Top

Back  -    New Search

inhibitor (in-hib-it-er) n.

a substance that prevents the occurrence of a given process or reaction. See also MAO INHIBITOR.

Back  -    New Search

injected (in-jekt-id) adj.

congested.

Back  -    New Search

injection (in-jek-shn) n.

introduction into the body of drugs or other fluids by means of a syringe. Common routes for injection are into the skin (intracutaneous or intradermal ); below the skin (subcutaneous ); into a muscle (intramuscular ), for drugs that are slowly absorbed; and into a vein (intravenous ), for drugs to be rapidly absorbed. Enemas are also regarded as injections.

Back  -    New Search

injury scoring system (injury severity scale, ISS) (in-jer-i) n.

a system used, particularly in triage, for grading the severity of an injury. See also ABBREVIATED INJURY SCALE.

Back  -    New Search

inlay (in-lay) n.

a substance or piece of tissue inserted to replace a defect in a tissue.

Back  -    New Search

innate (in-ayt) adj.

describing a condition or characteristic that is present in an individual at birth and is inherited from his parents. See also CONGENITAL.

Back  -    New Search

inner ear (in-er) n.

see LABYRINTH.

Back  -    New Search

innervation (in-er-vay-shn) n.

the nerve supply to an area or organ of the body.

Back  -    New Search

innocent (in--snt) adj.

(of a tumour) benign; not malignant.

Back  -    New Search

innominate artery (brachiocephalic artery) (in-om-in-it) n.

a short artery originating as the first large branch of the aortic arch, which divides at the lower neck into the right common carotid and the right subclavian arteries.

Back  -    New Search

innominate bone n.

see HIP (BONE).

Back  -    New Search

innominate vein (brachiocephalic vein) n.

either of two veins, one on each side of the neck, formed by the junction of the external jugular and subclavian veins. The two veins join to form the superior vena cava.

Back  -    New Search

ino- prefix

denoting
1 fibrous tissue.
2 muscle.

Back  -    New Search

inoculation (in-ok-yoo-lay-shn) n.

the introduction of a small quantity of material, such as a vaccine, in the process of immunization: a more general name for vaccination.

Back  -    New Search

inoculum (in-ok-yoo-lm) n.

any material that is used for inoculation.

Back  -    New Search

inorganic (in-or-gan-ik) adj.

1 not of animal or vegetable origin.

2 (in chemistry) describing or relating to compounds that do not contain carbon.
Top

Back  -    New Search

inositol (in-oh-sit-ol) n.

a compound, similar to a hexose sugar, that is a constituent of some cell phospholipids; it is present in the bran of cereal grain. It is sometimes classified as a vitamin but it can be synthesized by most animals and there is no evidence that it is an essential nutrient in humans.

Back  -    New Search

inositol triphosphate n.

see SECOND MESSENGER.

Back  -    New Search

inotropic (in--trop-ik) adj.

affecting the contraction of heart muscle. Such drugs as digitalis, dobutamine, and enoximone have positive inotropic action, stimulating heart muscle contractions. Beta-blocker drugs, such as propranolol, have negative inotropic action.

Back  -    New Search

in-patient (in-pay-shnt) n.

a patient who is admitted to a bed in a hospital ward and remains there for a period of time for treatment, examination, or observation. Compare OUT-PATIENT.

Back  -    New Search

inquest (in-kwest) n.

an official judicial enquiry into the cause of a person's death: carried out when the death is sudden or takes place under suspicious circumstances. See also AUTOPSY.

Back  -    New Search

insanity (in-san-iti) n.

a degree of mental illness such that the affected individual is not responsible for his actions. The term is a legal rather than a medical one.

Back  -    New Search

insect (in-sekt) n.

a member of a large group of mainly land-dwelling arthropods. Insects of medical importance include various bloodsucking insects transmitting tropical diseases; lice, whose bites can cause intense irritation and bacterial infection; and flies, which transmit organisms causing diarrhoea and dysentery to food. See also MYIASIS.

Back  -    New Search

insecticide (in-sekt-i-syd) n.

a preparation used to kill destructive or disease-carrying insects. Some insect powders contain organic phosphorus compounds and fluorides; when ingested accidentally they may cause damage to the nervous system. The use of such compounds is generally under strict control. See also DDT.

Back  -    New Search

insemination (in-sem-i-nay-shn) n.

introduction of semen into the vagina. See also ARTIFICIAL INSEMINATION.

Back  -    New Search

insertion (in-ser-shn) n.

(in anatomy) the point of attachment of a muscle (e.g. to a bone) that is relatively movable when the muscle contracts. Compare ORIGIN.

Back  -    New Search

insidious (in-sid-is) adj.

describing a disease that develops gradually and imperceptibly.

Back  -    New Search

insight (in-syt) n.

(in psychology) knowledge of oneself. The term is applied particularly to a patient's recognition that he has psychological problems; in this sense absence of insight is a feature of psychosis.

Back  -    New Search

in situ (in sit-yoo) adj.

1 in the natural or original position.

2 describing a cancer that has not undergone metastasis to invade surrounding tissue.
Top

Back  -    New Search

insolation (in-soh-lay-shn) n.

exposure to the sun's rays. See also HEATSTROKE.

Back  -    New Search

insomnia (in-som-ni) n.

inability to fall asleep or to remain asleep for an adequate length of time. Insomnia may be associated with disease, but is more often caused by worry.

Back  -    New Search

inspiration (in-spi-ray-shn) n.

see INHALATION.

Back  -    New Search

inspissated (in-spis-ayt-id) adj.

thickened or hardened by absorption or evaporation. i. sputum a thick sputum produced in whooping cough, which is difficult to cough up.

Back  -    New Search

instillation (in-stil-ay-shn) n.

1 the application of liquid medication drop by drop, as into the eye.

2 the medication applied in this way.
Top

Back  -    New Search

instinct (in-stinkt) n.

1 a complex pattern of behaviour innately determined, which is characteristic of all individuals of the same species.

2 an innate drive that urges the individual towards a particular goal.
Top

Back  -    New Search

institutionalization (in-sti-tyoo-shn-l-l-zay-shn) n.

a condition produced by long-term residence in an unstimulating impersonal institution (such as some residential care homes). The individual adapts to the behaviour characteristic of the institution to such an extent that he or she is handicapped in other environments. The features often include apathy, dependence, and a lack of personal responsibility.

Back  -    New Search

insufficiency (in-s-fish-n-si) n.

inability of an organ or part, such as the heart or kidney, to carry out its normal function.

Back  -    New Search

insufflation (in-suf-lay-shn) n.

the act of blowing gas or a powder, such as a medication, into a body cavity.

Back  -    New Search

insulin (ins-yoo-lin) n.

a protein hormone, produced in the pancreas by the beta cells of the islets of Langerhans, that is important for regulating the amount of sugar (glucose) in the blood. Lack of this hormone gives rise to diabetes mellitus, in which large amounts of sugar are present in the blood and urine. This condition may be treated successfully by insulin injections. i. shock see SHOCK.

Back  -    New Search

insulinase (ins-yoo-lin-ayz) n.

an enzyme, found in such tissues as the liver and kidney, that is responsible for the normal breakdown of insulin in the body.

Back  -    New Search

insulinoma (ins-yoo-lin-oh-m) n.

an insulin-producing tumour of the beta cells in the islets of Langerhans of the pancreas. Symptoms include sweating, faintness, and other features of hypoglycaemia (see WHIPPLE's TRIAD).

Back  -    New Search

insult (in-sult) n.

an injury or physical trauma.

Back  -    New Search

Intal (in-tal) n.

see CROMOLYN SODIUM.

Back  -    New Search

integument (in-teg-yoo-mnt) n.

1 the skin.

2 a membrane or layer of tissue covering any organ of the body.
Top

Back  -    New Search

intelligence quotient (IQ) (in-tel-i-jns kwoh-shnt) n.

an index of intellectual development. In childhood and adult life it represents intellectual ability relative to the rest of the population; in children it can also represent rate of development (mental age as a percentage of chronological age).

Back  -    New Search

intelligence test n.

a standardized assessment procedure for the determination of intellectual ability. The score produced is usually expressed as an intelligence quotient. Scores on intelligence tests are used for such purposes as the diagnosis of mental retardation and the assessment of intellectual deterioration.

Back  -    New Search

intensive care (intensive therapy) (in-ten-siv) n.

specialized and monitored health care provided for critically ill and immediately postoperative patients by specialist multidisciplinary staff in a specially designed hospital unit (i. c. or i. t. unit ). See also CORONARY CARE.

Back  -    New Search

intention (in-ten-shn) n.

a process of healing. first i. healing in which the edges of a wound are brought together under aseptic conditions and granulation tissue forms. second i. healing in which the wound edges are separated and the cavity is filled with granulation tissue over which epithelial tissue grows from the wound edges. third i. healing in which the wound ulcerates, granulations are slow to form, and a scar forms at the wound site.

Back  -    New Search

intention tremor n.

see TREMOR.

Back  -    New Search

inter- prefix

denoting between.

Back  -    New Search

intercalated (inter-k-layt-id) adj.

describing structures, tissues, etc., that are inserted or situated between other structures.

Back  -    New Search

intercellular (inter-sel-yoo-ler) adj.

situated or occurring between cells.

Back  -    New Search

intercostal muscles (inter-kos-t'l) pl. n.

muscles that occupy the spaces between the ribs and are responsible for controlling some of the movements of the ribs.

Back  -    New Search

intercurrent (inter-ku-rnt) adj.

going on at the same time: applied to an infection contracted by a patient who is already suffering from an infection or other disease.

Back  -    New Search

interferon (inter-feer-on) n.

a substance that is produced by cells infected with a virus and has the ability to inhibit viral growth. Particular interferons are effective only in the species that produces them. Human interferon produced by genetic engineering is now used clinically in treating hepatitis B and C, hairy-cell leukaemia, Kaposi's sarcoma, and multiple sclerosis.

Back  -    New Search

interkinesis (inter-ky-nee-sis) n.

1 the resting stage between the two divisions of meiosis.

2 see INTERPHASE.
Top

Back  -    New Search

interleukin (inter-lew-kin) n.

any of a family of 12 proteins that control aspects of haemopoiesis and the immune response. interleukin 2 (IL-2 ) an interleukin that stimulates T-lymphocytes and is being investigated for the treatment of cancer (see ALDESLEUKIN).

Back  -    New Search

intermenstrual (inter-men-stroo-l) adj.

between the menstrual periods.

Back  -    New Search

intermittent claudication (inter-mit-nt) n.

see CLAUDICATION.

Back  -    New Search

intermittent fever n.

a fever that rises, subsides, then returns again. See MALARIA.

Back  -    New Search

intermittent self-catheterization (ISC, clean intermittent self-catheterization, CISC) n.

a procedure in which the patient periodically passes a disposable catheter through the urethra into the bladder for the purpose of emptying it of urine. It is increasingly used in the management of patients of both sexes (including children) with chronic retention and large residual urine volumes, often due to neuropathic bladder. ISC may prevent back pressure and dilatation of the upper urinary tract with consequent infection and incontinence.

Back  -    New Search

International Classification of Diseases (ICD) (inter-nash-n-l) n.

a list of all known diseases and syndromes published by the World Health Organization every ten years (approximately).

Back  -    New Search

interoceptor (inter-oh-sep-ter) n.

any receptor organ composed of sensory nerve cells that respond to and monitor changes within the body, such as the stretching of muscles or the acidity of the blood.

Back  -    New Search

interosseous (inter-oss-i-s) adj.

between two bones.

Back  -    New Search

interparietal bone (inca bone, incarial bone) (inter-p-ry-i-t'l) n.

the bone lying between the parietal bones, at the back of the skull.

Back  -    New Search

interphase (interkinesis) (in-ter-fayz) n.

the period when a cell is not undergoing division (mitosis), during which activities such as DNA synthesis occur.

Back  -    New Search

intersex (in-ter-seks) n.

an individual who shows anatomical characteristics of both sexes. See HERMAPHRODITE.
—intersexuality n.

Back  -    New Search

interstice (in-ter-stiss) n.

a small space in a tissue or between parts of the body.
—interstitial (inter-stish-l) adj.

Back  -    New Search

interstitial cells (Leydig cells) pl. n.

the cells interspersed between the seminiferous tubules of the testis. They secrete androgens in response to stimulation by luteinizing hormone.

Back  -    New Search

interstitial-cell-stimulating hormone n.

see LUTEINIZING HORMONE.

Back  -    New Search

interstitial cystitis n.

a chronic nonbacterial inflammation of the bladder accompanied by an urgent desire to pass urine frequently and bladder pain; it is usually associated with an ulcer in the bladder wall (Hunner's ulcer ). The cause is unknown and contracture of the bladder eventually occurs.

Back  -    New Search

intertrigo (inter-try-goh) n.

superficial inflammation of two skin surfaces that are in contact. It is caused by friction and sweat.

Back  -    New Search

interventional radiology (inter-ven-shn-al) n.

see RADIOLOGY.

Back  -    New Search

intervertebral disc (inter-ver-tib-rl) n.

the flexible plate of fibrocartilage that connects any two adjacent vertebrae in the backbone. The intervertebral discs act as shock absorbers, protecting the brain and spinal cord from the impact produced by running and other movements. See also PROLAPSED INTERVERTEBRAL DISC.

Back  -    New Search

intestinal flora (in-test-in-l) pl. n.

bacteria normally present in the intestinal tract. Some are responsible for the synthesis of vitamin K.

Back  -    New Search

intestinal juice n.

see SUCCUS (ENTERICUS).

Back  -    New Search

intestinal obstruction n.

see OBSTRUCTION.

Back  -    New Search

intestine (bowel, gut) (in-test-in) n.

the part of the alimentary canal that extends from the stomach to the anus. large i. the part that consists of the caecum, vermiform appendix, colon, and rectum. It is largely concerned with the absorption of water from the material passed from the small intestine. small i. the part of the intestine that consists of the duodenum, jejunum, and ileum. It is here that most of the processes of digestion and absorption of food take place. See illustration.

—intestinal adj.

Back  -    New Search

intima (tunica intima) (in-tim-) n.

1 the inner layer of the wall of an artery or vein. It is composed of a lining of endothelial cells and an elastic membrane.

2 the inner layer of various other organs or parts.
Top

Back  -    New Search

intolerance (in-tol-er-ns) n.

the inability of a patient to tolerate a particular drug, manifested by various adverse reactions.

Back  -    New Search

intoxication (in-toks-i-kay-shn) n.

the symptoms of poisoning due to ingestion of any toxic material, including alcohol.

Back  -    New Search

intra- prefix

denoting inside; within.

Back  -    New Search

intra-articular (intr-ar-tik-yoo-ler) adj.

within or into a joint.

Back  -    New Search

intracellular (intr-sel-yoo-ler) adj.

situated or occurring inside a cell or cells. Compare EXTRACELLULAR.

Back  -    New Search

intracranial (intr-kray-ni-l) adj.

within the skull.

Back  -    New Search

intradermal (intr-derm-l) adj.

within the skin. i. injection an injection that is made into the skin.

Back  -    New Search

intradural (intr-dewr-l) adj.

within or beneath the dura mater.

Back  -    New Search

intramedullary (intr-mi-dul-er-i) adj.

within the bone marrow.

Back  -    New Search

intramuscular (intr-mus-kew-ler) adj.

within a muscle. See also INJECTION.

Back  -    New Search

intraocular (intr-ok-yoo-ler) adj.

of or relating to the area within the eyeball. i. lens implant see IMPLANT.

Back  -    New Search

intrathecal (intr-th'ee-kl) adj.

1 within the meninges of the spinal cord.

2 within a sheath, e.g. a nerve sheath.
Top

Back  -    New Search

intrauterine (intr-yoo-teryn) adj.

within the uterus. i. contraceptive device see IUCD. i. growth retardation (IUGR) the condition resulting in the birth of a baby whose birth weight is abnormally low in relation to its gestational age (i.e. small for dates ; SFD). Causes include maternal disease (e.g. infection, malnutrition, high blood pressure, smoking, and alcoholism), poor socioeconomic conditions, multiple pregnancy (e.g. twins), and fetal disease. It may be associated with preterm birth. i. system see IUS.

Back  -    New Search

intravascular (intr-vas-kew-ler) adj.

within the blood vessels.

Back  -    New Search

intravenous (intr-vee-ns) adj.

into or within a vein. See also INFUSION, INJECTION. i. feeding see NUTRITION. i. pyelography see PYELOGRAPHY.

Back  -    New Search

intraversion (intr-ver-shn) n.

see INTROVERSION.

Back  -    New Search

intra vitam (in-tr vy-tam)

Latin: during life.

Back  -    New Search

intravitreal (intr-vit-ri-l) adj.

within the vitreous humour of the eye.

Back  -    New Search

intrinsic (in-trin-sik) adj.

exclusive to a part or body.

Back  -    New Search

intrinsic factor n.

a glycoprotein secreted in the stomach. The secretion of intrinsic factor is necessary for the absorption of vitamin B_12; a failure of secretion leads to a deficiency of the vitamin and the condition of pernicious anaemia.

Back  -    New Search

intro- prefix

denoting in; into.

Back  -    New Search

introitus (in-troh-it-s) n.

(in anatomy) an entrance into a hollow organ or cavity.

Back  -    New Search

introjection (intr-jek-shn) n.

(in psychoanalysis) the process of adopting, or of believing that one possesses, the qualities of another person. This can be a form of defence mechanism. See also IDENTIFICATION.

Back  -    New Search

introspection (intr-spek-shn) n.

the study by an individual of his own mental processes, reactions, etc.
—introspective adj.

Back  -    New Search

introversion (intr-ver-shn) n.

1 (or intraversion) an enduring personality trait characterized by interest in the self rather than the outside world. People high in introversion (introverts ) tend to have a small circle of friends, like to persist in activities once they have started, and are highly susceptible to permanent conditioning. Compare EXTROVERSION.

2 a turning inwards of a hollow organ (such as the uterus) on itself.
Top

Back  -    New Search

introvert (in-tr-vert) n.

see INTROVERSION.

Back  -    New Search

intubation (in-tew-bay-shn) n.

the introduction of a tube into part of the body for the purpose of diagnosis or treatment. gastric i. intubation performed to remove a sample of the stomach contents for analysis or to administer drugs directly into the stomach. tracheal i. introduction of an endotracheal tube to facilitate administration of general anaesthetics or oxygen.

Back  -    New Search

intumescence (in-tew-mes-ns) n.

a swelling or an increase in the volume of an organ.

Back  -    New Search

intussusception (in-ts-s-sep-shn) n.

the telescoping (invagination ) of one part of the bowel into another, resulting in intestinal obstruction. It is most common in young children under the age of four. Symptoms include intermittent colic or pain, vomiting, and the passing of red jelly with the stools; if the condition does not receive prompt surgical treatment, shock from gangrene of the bowel may result.

Back  -    New Search

inulin (in-yoo-lin) n.

a carbohydrate with a high molecular weight that is filtered from the bloodstream by the kidneys. i. clearance a test of kidney function in which inulin is injected into the blood. By measuring the amount that appears in the urine over a given period, it is possible to calculate how much filtrate the kidneys are producing.

Back  -    New Search

inunction (in-unk-shn) n.

the rubbing in with the fingers of an ointment or liniment.

Back  -    New Search

invagination (in-vaj-i-nay-shn) n.

1 the infolding of the wall of a solid structure to form a cavity.

2 see INTUSSUSCEPTION.
Top

Back  -    New Search

invasion (in-vay-zhn) n.

1 the onset of a disease.

2 the entry of bacteria into the body
Top
.
3 the destruction of healthy tissue by a malignant tumour.
Top

Back  -    New Search

invasive (in-vay-ziv) adj.

1 denoting tumours that spread into and destroy surrounding healthy tissue (see MALIGNANT).

2 denoting a surgical or diagnostic procedure that involves penetration of the skin or underlying organs and tissues by needles or knives.
Top

Back  -    New Search

inversion (in-ver-shn) n.

1 the turning inwards or inside-out of a part or organ: commonly applied to the state of the uterus after childbirth when its upper part is pulled through the cervical canal.

2 a chromosome mutation in which a block of genes within a chromosome are in reverse order.
Top

Back  -    New Search

invertase (in-ver-tayz) n.

an enzyme in intestinal juice that digest sugars.

Back  -    New Search

in vitro (in vee-troh)

Latin: describing biological phenomena that are made to occur outside the living body (traditionally in a test-tube).

Back  -    New Search

in vitro fertilization (IVF) n.

fertilization of an ovum outside the body, a technique used when a woman has blocked Fallopian tubes or some other impediment to the union of sperm and ovum in the reproductive tract. The woman is given hormone therapy causing a number of ova to mature at the same time (see SUPEROVULATION). Several of them are then removed from the ovary through a laparoscope. The ova are mixed with spermatozoa from her partner and incubated in a culture medium until the blastocyst is formed. The blastocyst is then implanted in the mother's uterus and the pregnancy allowed to continue normally.

Back  -    New Search

in vivo (in vee-voh)

Latin: describing biological phenomena that occur within the bodies of living organisms.

Back  -    New Search

involucrum (in-v-loo-krm) n.

a growth of new bone that sometimes surrounds a mass of infected and dead bone in osteomyelitis.

Back  -    New Search

involuntary muscle (in-vol-n-ter-i) n.

muscle that is not under conscious control, such as the muscle of the gut, stomach, blood vessels, and heart. See also CARDIAC MUSCLE, SMOOTH MUSCLE.

Back  -    New Search

involution (in-v-loo-shn) n.

1 the shrinking of the uterus to its normal size after childbirth.

2 atrophy of an organ in old age.
Top

—involutional (in-v-loo-shn-l) adj.

Back  -    New Search

involutional melancholia n.

a severe depression, usually psychotic, appearing for the first time in the involutional period of middle life (approximately 40–55 for women, 50–65 for men). Characteristic features include agitation; delusions of ill-health, poverty, and sin; and preoccupations with death and loss. See MANIC-DEPRESSIVE PSYCHOSIS.

Back  -    New Search

iodine (l--din) n.

an element required in small amounts for healthy growth and development. The thyroid gland requires iodine to synthesize thyroid hormones; a deficiency of the element leads to goitre. Radioactive isotopes of iodine (usually iodine-131 ) are used in the diagnosis and treatment of diseases of the thyroid gland. Iodine is also used as an antiseptic. Symbol: I.

Back  -    New Search

iodism (l--dizm) n.

iodine poisoning. The main features are a characteristic staining of the mouth and odour on the breath. Emergency treatment includes administration of starch or flour in water and lavage with sodium thiosulphate solution.

Back  -    New Search

ion (l-n) n.

an atom or group of atoms that has lost one or more electrons, making it electrically charged and therefore more chemically active. See ANION, CATION, ELECTROLYTE.

Back  -    New Search

ionization (I--ny-zay-shn) n.

1 the dissociation of a substance into ions. Some molecules ionize in solution (see ELECTROLYTE).

2 see IONTOPHORESIS.
Top

Back  -    New Search

iontophoresis (ionization) (I-on-toh-fer-ee-sis) n.

the technique of introducing through the skin, by means of an electric current, charged particles of a drug, so that it reaches a deep site. See also CATAPHORESIS.

Back  -    New Search

iopanoic acid (I-oh-p-noh-ik) n.

a radiopaque iodine-containing compound used in cholecystography. It is administered by intravenous injection.

Back  -    New Search

IOUS n.

intraoperative ultrasound examination. See ULTRASONOGRAPHY.

Back  -    New Search

ipecacuanha (ipi-kak-yoo-an-) n.

a plant extract used in small doses, usually in the form of tinctures and syrups, as an expectorant to relieve coughing and to induce vomiting.

Back  -    New Search

ipratropium (ip-r-troh-pim) n.

a bronchodilator drug used in the treatment of chronic reversible airways obstruction (see BRONCHOSPASM). It is administered by inhalation. Trade name: Atrovent .

Back  -    New Search

iprindole (i-prin-dohl) n.

a drug administered by mouth for the treatment of depression (see ANTIDEPRESSANT). Trade name: Prondol .

Back  -    New Search

ipsilateral (ipselateral, homolateral) (ip-si-lat-er-l) adj.

on or affecting the same side of the body. Compare CONTRALATERAL.

Back  -    New Search

IQ n.

see INTELLIGENCE QUOTIENT.

Back  -    New Search

irid- (irido-) prefix

denoting the iris.

Back  -    New Search

iridectomy (i-ri-dek-tmi) n.

an operation on the eye in which a part of the iris is removed.

Back  -    New Search

iridocele (i-rid-oh-seel) n.

the protrusion of part of the iris through a wound in the cornea.

Back  -    New Search

iridocyclitis (i-ri-doh-sy-kly-tis) n.

inflammation of the iris and ciliary body of the eye. See UVEITIS.

Back  -    New Search

iridodialysis (i-ri-doh-dy-al-i-sis) n.

a tear, caused by injury to the eye, in the attachment of the iris to the ciliary body.

Back  -    New Search

iridoplegia (i-ri-doh-plee-ji) n.

paralysis of the iris, which is usually associated with cycloplegia and results from injury, inflammation, or the use of pupil-dilating eye drops.

Back  -    New Search

iridoptosis (i-ri-dop-t-sis) n.

prolapse of the iris.

Back  -    New Search

iridotomy (i-ri-dot-mi) n.

an operation on the eye in which an incision is made in the iris using a knife or a YAG laser.

Back  -    New Search

iris (l-ris) n.

the part of the eye that regulates the amount of light that enters. It forms a coloured muscular diaphragm across the front of the lens; light enters through a central opening (the pupil). Contraction of different sets of muscles of the iris causes the pupil to dilate in dim light and to contract in bright light. i. bombé an abnormal condition of the eye in which the iris bulges forward towards the cornea.

Back  -    New Search

iritis (I-ry-tis) n.

inflammation of the iris. See UVEITIS.

Back  -    New Search

iron (l-n) n.

an element essential to life. The body of an adult contains on average 4 g of iron, over half of which is contained in haemoglobin in the red blood cells. Iron is an essential component in the transfer of oxygen in the body; a deficiency of iron may lead to anaemia. Many preparations of iron are used to treat iron-deficiency anaemia. Symbol: Fe.

Back  -    New Search

iron dextran n.

a drug containing iron and dextran, administered by intramuscular or intravenous injection to treat iron-deficiency anaemia. Trade name: lmferon .

Back  -    New Search

iron lung n.

see RESPIRATOR.

Back  -    New Search

iron-storage disease n.

see HAEMOCHROMATOSIS.

Back  -    New Search

irradiation (i-ray-di-ay-shn) n.

1 exposure of the body's tissues to ionizing radiation. The source may be background radiation, diagnostic X-rays, radiotherapy, or nuclear accidents.

2 exposure of a substance or object to ionizing radiation. Irradiation of food with gamma rays to kill bacteria is a technique used in food preservation.
Top

Back  -    New Search

irreducible (i-ri-dew-sibl) adj.

unable to be replaced in a normal position: applied particularly to a type of hernia.

Back  -    New Search

irrigation (i-ri-gay-shn) n.

the process of washing out a wound or hollow organ with a continuous flow of water or medicated solution. whole-gut i. washing out the entire intestinal tract as a prelude to surgery on the lower intestine.

Back  -    New Search

irritability (i-ri-t-bil-iti) n.

(in physiology) the property of certain kinds of tissue that enables them to respond in a specific way to outside stimuli.

Back  -    New Search

irritable bowel syndrome (IBS, spastic colon, mucous colitis) (i-ri-t-bl) n.

a common condition in which recurrent abdominal pain with constipation and/or diarrhoea continues for years without any general deterioration in physical health or detectable structural disease.

Back  -    New Search

irritant (i-ri-tnt) n.

any material that causes irritation of a tissue.

Back  -    New Search

isch- (ischo-) prefix

denoting suppression or deficiency.

Back  -    New Search

ischaemia (isk-ee-mi) n.

an inadequate flow of blood to a part of the body, caused by constriction or blockage of the blood vessels supplying it.
—ischaemic adj.

Back  -    New Search

ischi- (ischio-) prefix

denoting the ischium.

Back  -    New Search

ischiorectal abscess (isk-i-oh-rek-t'l) n.

an abscess in the space between the sheet of muscle that assists in control of the rectum and the pelvic bone. Symptoms are severe throbbing pain near the anus with swelling and fever; it may cause an anal fistula. Pus is drained from the abscess by surgical incision.

Back  -    New Search

ischium (isk-im) n.

a bone forming the lower part of each side of the hip bone (see also PELVIS).
—ischiac, ischial adj.

Back  -    New Search

ischuria (isk-yoor-i) n.

retention or suppression of the urine. See ANURIA, RETENTION.

Back  -    New Search

islets of Langerhans (l-lits v lang-er-hans) pl. n.

small groups of cells, scattered through the material of the pancreas, that secrete the hormones insulin and glucagon. See also ALPHA CELLS, BETA CELLS. [P. Langerhans (1847–88), German pathologist]

Back  -    New Search

iso- prefix

denoting equality, uniformity, or similarity.

Back  -    New Search

isoantibody (I-soh-an-ti-bodi) n.

an antibody that occurs naturally against the components of foreign tissues from an individual of the same species.

Back  -    New Search

isoantigen (I-soh-an-ti-jn) n.

an antigen that forms a natural component of an individual's tissues.

Back  -    New Search

isoimmunization (I-soh-im-yoo-ny-zay-shn) n.

the development of antibodies (isoantibodies) within an individual against antigens from another individual of the same species.

Back  -    New Search

isolation (I-s-lay-shn) n.

1 the separation of a person with an infectious disease from noninfected people. See also QUARANTINE.

2 (in surgery) the separation of a structure from surrounding structures by the use of instruments.
Top

Back  -    New Search

isolator (l-s-lay-ter) n.

a large transparent plastic bag in which a patient can be nursed or operated upon without the danger of contamination by infective agents.

Back  -    New Search

isoleucine (I-soh-loo-seen) n.

an essential amino acid. See also AMINO ACID.

Back  -    New Search

isometheptene (I-soh-meth-ep-teen) n.

a sympathomimetic drug used in the treatment of migraine, either alone or in combination with paracetamol (as Midrid ). It is administered by mouth.

Back  -    New Search

isometric (I-soh-met-rik) adj.

of or denoting muscular contraction that does not cause muscle shortening. i. exercise see EXERCISE.

Back  -    New Search

isomorphism (I-soh-mor-fizm) n.

the condition of two or more objects being alike in shape or structure.
—isomorphic, isomorphous adj.

Back  -    New Search

isoniazid (isonicotinic acid hydrazide, INH) (I-soh-ny--zid) n.

a drug used in the treatment of tuberculosis, usually taken by mouth. Because tuberculosis bacteria soon become resistant to isoniazid, it is usually given in conjunction with streptomycin and other antibiotics.

Back  -    New Search

isoprenaline (I-soh-pren--leen) n.

a sympathomimetic drug used to dilate the air passages in asthma and other bronchial conditions. It also stimulates the heart and is used to treat some heart conditions involving reduced heart activity. It is administered by inhalation, by mouth, by injection, or in suppositories. Trade names: Medihaler-Iso , Saventrine .

Back  -    New Search

isosorbide dinitrate (I-soh-sor-byd dy-ny-trayt) n.

a drug administered by mouth for the treatment of angina in patients unable to take glyceryl trinitrate. It acts by relaxing the smooth muscle of both arteries and veins, thus causing dilation. Trade names: Cedocard , Isoket , Isordil , Sorbitrate .

Back  -    New Search

isosthenuria (I-sos-thn-yoor-i) n.

inability of the kidneys to produce either a concentrated or a dilute urine. This occurs in the final stages of renal failure.

Back  -    New Search

isotonic (I-soh-ton-ik) adj.

1 describing solutions that have the same osmotic pressure. See OSMOSIS.

2 describing muscles that have equal tonicity. i. exercise see EXERCISE.
Top

Back  -    New Search

isotope (I-s-tohp) n.

any one of the different forms of an element, having the same atomic number but different atomic weights. Radioactive isotopes decay into other isotopes or elements, emitting alpha, beta, or gamma radiation. Artificially produced radioactive isotopes are used extensively as tracers (see also GAMMA CAMERA, SCINTIGRAM) and in radiotherapy for the treatment of cancer.

Back  -    New Search

isotretinoin (I-soh-tre-tin-oh-in) n.

a drug related to vitamin A (see RETINOID) and used in the treatment of severe acne that has failed to respond to other treatment. It is administered by mouth. Trade name: Roaccutane .

Back  -    New Search

isoxsuprine (I-soks-yoo-preen) n.

a drug that dilates blood vessels and is administered by mouth or injection to improve blood flow in such conditions as cerebrovascular disease and arteriosclerosis and to inhibit contractions in premature labour. Trade name: Duvalidan .

Back  -    New Search

ispaghula husk (iss-pag-yoo-l husk) n.

a bulking agent (see LAXATIVE) used to treat constipation, diverticulitis, and irritable bowel syndrome. It is administered by mouth. Trade names: Colven , Fybogel .

Back  -    New Search

ISS n.

see INJURY SCORING SYSTEM.

Back  -    New Search

isthmus (iss-ms) n.

a constricted or narrowed part of an organ or tissue.

Back  -    New Search

itch (ich) n.

local discomfort or irritation of the skin, prompting the sufferer to scratch or rub the affected area. See PRURITUS.

Back  -    New Search

-itis suffix

denoting inflammation of an organ, tissue, etc.

Back  -    New Search

IUCD (intrauterine contraceptive device) n.

a plastic or metal coil, spiral, or other shape, about 25 mm long, that is inserted into the cavity of the uterus to prevent conception. Its exact mode of action is unknown but it is thought to interfere with implantation of the embryo. See also POSTCOITAL (CONTRACEPTION).

Back  -    New Search

IUGR n.

see INTRAUTERINE (GROWTH RETARDATION).

Back  -    New Search

IUS (intrauterine system) n.

a removable hormonal contraceptive device that is inserted into the uterus. Consisting of a plastic T-shaped frame that carries a hormone (progestogen) in a sleeve around its stem, it provides a long-term method of contraception that is also reversible. Trade name: Mirena .

Back  -    New Search

ivermectin (I-ver-mek-tin) n.

a drug used in the treatment of onchocerciasis. It is administered by mouth and acts by killing the immature forms (microfilariae) of the parasite.

Back  -    New Search

IVF n.

see IN VITRO FERTILIZATION.

Back  -    New Search

ixodiasis (iks-oh-dy--sis) n.

any disease caused by the presence of ticks.

Back  -    New Search

J

Jacksonian epilepsy (jak-sohn-in) n.

see EPILEPSY. [J. H. Jackson (1835–1911), British neurologist]

Back  -    New Search

Jacquemier's sign (zhak-mi-ayz) n.

a bluish or purplish coloration of the vagina: a possible indication of pregnancy. [J. M. Jacquemier (1806–79), French obstetrician]

Back  -    New Search

jactitation (jak-ti-tay-shn) n.

restless tossing and turning of a person suffering from a severe disease, frequently one with a high fever.

Back  -    New Search

jamais vu (zha-may-vew) n.

one of the manifestations of temporal lobe epilepsy, in which there is a sudden feeling of unfamiliarity with everyday surroundings.

Back  -    New Search

Jarisch-Herxheimer reaction (Herxheimer reaction) (yar-ish herks-hy-mer) n.

exacerbation of the symptoms of syphilis that may occur on starting antibiotic therapy for the disease.
The effect is transient and requires no treatment. [A. Jarisch (1850–1902), Austrian dermatologist; K. Herxheimer (1861–1944), German dermatologist]

Back  -    New Search

jaundice (jawn-dis) n.

a yellowing of the skin or whites of the eyes, indicating excess bilirubin in the blood. haemolytic j. jaundice that occurs when there is excessive destruction of red cells in the blood (see HAEMOLYSIS). hepatocellular j. jaundice due to disease of the liver cells, such as hepatitis. obstructive j. jaundice that occurs when bile made in the liver fails to reach the intestine due to obstruction of the bile ducts (e.g. by gallstones) or to cholestasis. Medical name: icterus .

Back  -    New Search

jaw (jaw) n.

either the maxilla (upper jaw) or the mandible (lower jaw).

Back  -    New Search

jejun- (jejuno-) prefix

denoting the jejunum.

Back  -    New Search

jejunal ulcer (ji-joo-nl) n.

see PEPTIC (ULCER), ZOLLINGER-ELLISON SYNDROME.

Back  -    New Search

jejunectomy (ji-joo-nek-tmi) n.

surgical removal of the jejunum or part of the jejunum.

Back  -    New Search

jejunoileostomy (ji-joo-noh-ili-ost-mi) n.

an operation in which the jejunum is joined to the ileum (small intestine), when either the end of the jejunum or the beginning of the ileum has been removed or is to be bypassed.

Back  -    New Search

jejunostomy (ji-joo-nost-mi) n.

a surgical operation in which the jejunum is brought through the abdominal wall and opened. It can enable the insertion of a catheter into the jejunum for short-term infusion of nutrients or other substances.

Back  -    New Search

jejunotomy (ji-joo-not-mi) n.

a surgical incision into the jejunum in order to inspect the interior or remove something from within it.

Back  -    New Search

jejunum (ji-joo-nm) n.

part of the small intestine. It comprises about two-fifths of the whole small intestine and connects the duodenum to the ileum.
—jejunal adj.

Back  -    New Search

jerk (jerk) n.

the sudden contraction of a muscle in response to a nerve impulse. knee j. see PATELLAR REFLEX.

Back  -    New Search

joint (joint) n.

the point at which two or more bones are connected. The opposing surfaces of bone are lined with cartilaginous, fibrous, or soft (synovial) tissue. See also AMPHIARTHROSIS, DIARTHROSIS, SYNARTHROSIS.

Back  -    New Search

joule (jool) n.

the SI unit of work or energy, equal to the work done when the point of application of a force of 1 newton is displaced through a distance of 1 metre in the direction of the force. Symbol: J. See also CALORIE.

Back  -    New Search

jugular (jug-yoo-ler) adj.

relating to or supplying the neck or throat. j. vein any one of several veins in the neck. internal j. a very large paired vein running vertically down the side of the neck and draining blood from the brain, face, and neck into the subclavian vein.

Back  -    New Search

jumper's knee (patellar tendinitis) (jump-erz) n.

a form of tendinitis that occurs in athletes and dancers. Repeated sudden contracture of the quadriceps muscle at take-off causes inflammation of the attachment of the patellar tendon to the lower end of the patella.

Back  -    New Search

junction (junk-shn) n.

(in anatomy) the point at which two different tissues or structures are in contact. See also NEUROMUSCULAR JUNCTION.

Back  -    New Search

juvenile polyp (joo-v-nyl) n.

see POLYP.

Back  -    New Search

juxta- prefix

denoting proximity to.

Back  -    New Search

K

K

symbol for potassium.

Back  -    New Search

Kahn reaction (kahn) n.

a test for syphilis, in which antibodies specific to the disease are detected in a sample of the patient's blood by means of a precipitin reaction. This test is not as reliable as some. [R. L. Kahn (20th century), US bacteriologist]

Back  -    New Search

kala-azar (visceral leishmaniasis, Dumdum fever) (kah-l--zar) n.

a tropical disease caused by the parasitic protozoan Leishmania donovani, which is transmitted to man by sandflies. Symptoms include enlargement and subsequent lesions of the liver and spleen; anaemia; a low leucocyte count; weight loss; and irregular fevers.

Back  -    New Search

kanamycin (kan--my-sin) n.

an antibiotic used to treat a wide range of bacterial infections. It is administered mainly by injection but is given by mouth for infections of the intestine and by inhalation for respiratory infections. Trade name: Kannasyn .

Back  -    New Search

kaolin (kay--lin) n.

a white clay that contains aluminium and silicon and is purified and powdered for use as an adsorbent. It is taken by mouth to treat diarrhoea and vomiting. Kaolin is also used in dusting powders and poultices.

Back  -    New Search

Kaposi's sarcoma (kap-oh-siz) n.

a malignant tumour arising from blood vessels in the skin and appearing as purple to dark brown plaques or nodules. It is common in Africa but rare in the Western world, except in patients with AIDS. The tumour evolves slowly; radiotherapy is the treatment of choice but chemotherapy may be of value in metastatic disease. See AIDS. [M. Kaposi (1837–1902), Austrian dermatologist]

Back  -    New Search

Kartagener's syndrome (kar-tah-gay-nerz) n.

a hereditary condition in which the heart and other internal organs lie on the opposite side of the body to the norm (i.e. the heart lies on the right; see DEXTROCARDIA); it is associated with chronic sinusitis and bronchiectasis. [M. Kartagener (1897–1975), German physician]

Back  -    New Search

kary- (karyo-) prefix

denoting a cell nucleus.

Back  -    New Search

karyokinesis (ka-ri-oh-ky-nee-sis) n.

division of the nucleus of a cell, which occurs during cell division before division of the cytoplasm (cytokinesis ). See MITOSIS.

Back  -    New Search

karyotype (ka-ri--typ)

1 n. the chromosome set of an individual or species described in terms of both the number and structure of the chromosomes.

2 n. the representation of the chromosome set in a diagram.
Top

3 vb. to determine the karyotype of a cell, as by microscopic examination.
Top

Back  -    New Search

katathermometer (kat--ther-mom-it-er) n.

a thermometer used to measure the cooling power of the air surrounding it.

Back  -    New Search

Kawasaki disease (mucocutaneous lymph node syndrome) (kah-w-sah-ki) n.

a condition of unknown cause affecting young children, usually less than five years old, and characterized by fever, conjunctivitis, a sore throat, and a generalized rash and reddening of the palms and soles. This is followed by peeling of the fingers and toes. The fever usually persists for 1–2 weeks. Approximately one-fifth of children develop myocarditis and aneurysms of the coronary arteries. Treatment involves aspirin therapy, and gamma-globulin has recently been shown to reduce the risk of coronary artery disease. [T. Kawasaki (20th century), Japanese physician]

Back  -    New Search

Kayser-Fleischer ring (ky-zer fly-sher) n.

a brownish-yellow ring in the outer rim of the cornea of the eye. It is a deposit of copper granules and is diagnostic of Wilson's disease. [B. Kayser (1869–1954), German ophthalmologist; B. Fleischer (1848–1904), German physician]

Back  -    New Search

Kehr's sign (kairz) n.

pain in the left shoulder caused by irritation of the undersurface of the diaphragm by blood leaking from a ruptured spleen. The pain impulses are referred along the phrenic nerve. [H. Kehr (1862–1913), German surgeon]

Back  -    New Search

Kell antigens (kel) pl. n.

a group of antigens that may or may not be present on the surface of red blood cells, forming the basis of a blood group. This group is important in blood transfusion reactions. [Mrs Kell (20th century), patient in whom they were first demonstrated]

Back  -    New Search

Keller's operation (kel-erz) n.

a surgical operation to correct hallux valgus or hallux rigidus, usually in elderly patients, in which the base of the first phalanx of the big toe is excised. [W. L. Keller (1874–1959), US surgeon]

Back  -    New Search

keloid (kee-loid) n.

an overgrowth of fibrous scar tissue following trauma to the skin. It does not resolve spontaneously but may be flattened by applied pressure or with injections of potent corticosteroids. Keloid formation is particularly common at certain sites, such as the breastbone or ear lobe.

Back  -    New Search

kerat- (kerato-) prefix

denoting 1 the cornea.

2 horny tissue, especially of the skin.
Top

Back  -    New Search

keratectasia (ke-r-tek-tay-zi) n.

bulging of the cornea at the site of scar tissue (which is thinner than normal corneal tissue).

Back  -    New Search

keratectomy (ke-r-tek-tmi) n.

an operation in which a part of the cornea is removed, usually a superficial layer. This procedure is now frequently done by an excimer laser or an automated keratome (automated lamellar k. ).

Back  -    New Search

keratin (ke-r-tin) n.

one of a family of proteins that are the major constituents of the nails, hair, and the outermost layers of the skin.

Back  -    New Search

keratinization (cornification) (ke-r-tin-l-zay-shn) n.

the process by which cells become horny due to the deposition of keratin within them. It occurs in the epidermis of the skin and associated structures (hair, nails, etc.).

Back  -    New Search

keratinocyte (ke-rat-in--syt) n.

a type of cell that makes up 95% of the cells of the epidermis. Keratinocytes migrate from the deeper layers of the epidermis and are finally shed from the surface of the skin.

Back  -    New Search

keratitis (ke-r-ty-tis) n.

inflammation of the cornea of the eye. The eye waters and is very painful and vision is blurred. It may be due to physical or chemical agents or result from infection. disciform k. inflammation within the cornea, usually as an immune response to viral infection, commonly herpes simplex virus. interstitial k. inflammation within the layers of the cornea caused by syphilis, leprosy, or tuberculosis.

Back  -    New Search

keratoconjunctivitis (ke-r-toh-kn-junk-ti-vy-tis) n.

combined inflammation of the cornea and conjunctiva of the eye. k. sicca dryness of the cornea and conjunctiva due to deficient tear production, as occurs in Sjögren's syndrome, systemic lupus, systemic sclerosis, and sarcoidosis.

Back  -    New Search

keratoconus (ke-r-toh-koh-ns) n.

conical cornea: an abnormal condition of the eye in which the cornea, instead of having a regular curvature, comes to a rounded apex towards its centre.

Back  -    New Search

keratoglobus (megalocornea) (ke-r-toh-gloh-bs) n.

a congenital disorder of the eye in which the whole cornea bulges forward in a regular curve. Compare KERATOCONUS.

Back  -    New Search

keratolytic (ke-r-toh-lit-ik) n.

an agent, such as salicylic acid, that breaks down the outer horny layer of epidermis and is used for treating warts.

Back  -    New Search

keratomalacia (ke-r-toh-m-lay-shi) n.

a progressive nutritional disease of the eye due to vitamin A deficiency. The cornea softens and may become perforated. See also XEROPHTHALMIA.

Back  -    New Search

keratome (ke-r-tohm) n.

any instrument designed for cutting the cornea.

Back  -    New Search

keratometer (ophthalmometer) (ke-r-tom-it-er) n.

an instrument for measuring the radius of curvature of the cornea. It is used for assessing the degree of abnormal curvature of the cornea in astigmatism.
—keratometry n.

Back  -    New Search

keratopathy (ke-r-top--thi) n.

any disorder relating to the cornea.

Back  -    New Search

keratoplasty (corneal graft) (ke-r-toh-plasti) n.

an eye operation in which any diseased parts of the cornea are replaced by clear corneal tissue from a donor.

Back  -    New Search

keratoprosthesis (ke-r-toh-pros-th'ee-sis) n.

an optically clear prosthesis that is implanted into the cornea to replace an area that has become opaque.

Back  -    New Search

keratoscope (Placido's disc) (ke-r-toh-skohp) n.

an instrument for detecting abnormal curvature of the cornea. It consists of a black disc marked with concentric white rings. The examiner looks at the reflection of the rings in the patient's cornea; a cornea that is abnormally curved (for example in keratoconus) or scarred reflects distorted rings.

Back  -    New Search

keratosis (ke-r-toh-sis) n.

a horny overgrowth of the skin. actinic (or solar ) k. a red spot with a scaly surface, which may occasionally become malignant. These spots are found in older fair-skinned people who have been chronically overexposed to the sun. seborrhoeic k. (basal-cell papilloma ) a superficial yellowish spot that never becomes malignant. Such spots occur especially on the trunk in middle age, slowly darkening and becoming warty over the years.

Back  -    New Search

keratotomy (ke-r-tot-mi) n.

an incision into the cornea. arcuate k. a curved incision in the periphery of the cornea to reduce astigmatism.

Back  -    New Search

keratouveitis (ke-r-toh-yoo-vi-l-tis) n.

inflammation involving both the cornea (see KERATITIS) and the uvea (see UVEITIS).

Back  -    New Search

kerion (keer-in) n.

an uncommon and severe form of tinea (ringworm) of the scalp consisting of a painful inflamed mass. It is caused by a fungus that usually infects animal species.

Back  -    New Search

kernicterus (ker-nik-ter-s) n.

staining and subsequent damage of the brain by bile pigment (bilirubin), which may occur in severe cases of haemolytic disease of the newborn.

Back  -    New Search

Kernig's sign (ker-nigz) n.

a symptom of meningitis in which the patient is unable to extend his legs at the knee when the thighs are held at a right angle to the body. [V. Kernig (1840–1917), Russian physician]

Back  -    New Search

ketamine (ket--meen) n.

a drug used to produce anaesthesia, mainly in children. It is administered by injection. Trade name: Ketalar .

Back  -    New Search

ketoacidosis (kee-toh-asid-oh-sis) n.

a lifethreatening condition in which acidosis is accompanied by ketosis, such as occurs in diabetes mellitus. Symptoms include nausea and vomiting, abdominal tenderness, confusion or coma, extreme thirst, and weight loss.

Back  -    New Search

ketoconazole (kee-toh-kon--zohl) n.

an antifungal drug (see IMIDAZOLE) that is used in the treatment of such fungal diseases as candidosis, histoplasmosis, and blastomycosis. It is taken by mouth. Trade name: Nizoral .

Back  -    New Search

ketogenesis (kee-toh-jen-i-sis) n.

the production of ketone bodies. These are normal products of lipid metabolism and can be used to provide energy.

Back  -    New Search

ketogenic diet (kee-toh-jen-ik) n.

a diet that promotes the formation of ketone bodies in the tissues, in which the principal energy source is fat rather than carbohydrate.

Back  -    New Search

ketonaemia (kee-toh-nee-mi) n.

the presence in the blood of ketone bodies.

Back  -    New Search

ketone (kee-tohn) n.

any member of a group of organic compounds consisting of a carbonyl group (=CO) flanked by two alkyl groups. k. bodies (acetone bodies ) the ketones acetoacetic acid, acetone, and ß-hydroxybutyrate, produced during the metabolism of fats. See also KETOSIS.

Back  -    New Search

ketonuria (acetonuria) (kee-tohn-yoor-i) n.

the presence in the urine of ketone bodies. This may occur in diabetes mellitus, starvation, or after persistent vomiting and results from the partial oxidation of fats.

Back  -    New Search

ketoprofen (kee-toh-proh-fen) n.

an analgesic that reduces inflammation, administered by mouth to treat various arthritic and rheumatic diseases. Trade names: Orudis , Oruvail .

Back  -    New Search

ketosis (kee-toh-sis) n.

raised levels of ketone bodies in the body tissues, resulting from an imbalance in fat metabolism. Ketosis may result in severe acidosis. See also KETONURIA.

Back  -    New Search

ketosteroid (kee-toh-steer-oid) n.

a steroid that contains one or more ketone groups (-C=O). 17-ketosteroids (having the oxygen at carbon 17) are normally excreted in the urine; excess 17-ketosteroids in the urine indicates overactivity of the adrenal glands and gonads.

Back  -    New Search

keyhole surgery (kee-hohl) n.

see MINIMALLY INVASIVE SURGERY.

Back  -    New Search

kidney (kid-ni) n.

either of the pair of organs responsible for the excretion of nitrogenous wastes, principally urea, from the blood (see illustration). The active units of the kidney are the nephrons, which filter the blood under pressure and then reabsorb water and selected substances back into the blood. The urine thus formed is conducted via the renal tubules to the ureter, which leads to the bladder. See also HAEMODIALYSIS, HORSESHOE KIDNEY, RENAL (FUNCTION TESTS).

Back  -    New Search

Kienböck's disease (keen-berks) n.

necrosis of the lunate bone of the wrist caused by interruption of its blood supply. It usually follows chronic stress to the bone or injury, often trivial. See also OSTEOCHONDRITIS. [R. Kienböck (1871–1953), Austrian radiologist]

Back  -    New Search

killer cell (kil-er) n.

see NATURAL KILLER CELL, T-CELL.

Back  -    New Search

Killian's operation (kil-inz) n.

a surgical operation in which part of the frontal bone is removed to allow drainage of the frontal sinus (see PARANASAL SINUSES), when this is filled with pus. [G. Killian (1860–1921), German otorhinolaryngologist]

Back  -    New Search

kilo- prefix

denoting a thousand.

Back  -    New Search

kilogram (kil--gram) n.

the SI unit of mass equal to 1000 grams. Symbol: kg.

Back  -    New Search

Kimmelstiel-Wilson disease (kim-l-steel wil-sn) n.

a disease in which diabetes mellitus is associated with the nephrotic syndrome, which results from breakdown of the glomeruli of the kidneys. [P. Kimmelstiel (1900–70), German-born pathologist; C. Wilson (1906– ), British physician]

Back  -    New Search

kin- (kine-) prefix

denoting movement.

Back  -    New Search

kinaesthesia (kin-iss-theez-i) n.

the sense that enables the brain to be constantly aware of the position and movement of muscles in different parts of the body.

Back  -    New Search

kinanaesthesia (kin-anis-theez-i) n.

inability to sense the positions and movements of parts of the body, with consequent disordered physical activity.

Back  -    New Search

kinase (ky-nayz) n.

1 an agent that can convert the inactive form of an enzyme (see PROENZYME) to the active form.

2 an enzyme that catalyses the transfer of phosphate groups.
Top

Back  -    New Search

kinematics (kin-i-mat-iks) n.

the study of motion and the forces required to produce it. This includes the different forces at work during the movement of a single part of the body, and more complex movements such as running and climbing.

Back  -    New Search

kineplasty (kin-i-plasti) n.

a method of amputation in which the muscles and tendons of the affected limb are arranged so that they can be integrated with a specially made artificial replacement.

Back  -    New Search

-kinesis suffix

denoting movement.

Back  -    New Search

kinetochore (ky-nee-toh-kor) n.

see CENTROMERE.

Back  -    New Search

King's model (kingz) n.

a model for nursing based on the view that individuals function in social systems through interpersonal relationships. Nursing is seen as a process of action, reaction, interaction, and transaction in order to set and achieve goals that meet the care needs of the patient. See also NURSING MODELS. [I. King (1909– ), US nurse theorist]

Back  -    New Search

kinin (ky-nin) n.

one of a group of naturally occurring polypeptides that are powerful vasodilators, which lower blood pressure, and cause contraction of smooth muscle.

Back  -    New Search

Kirschner's wire (keersh-nerz) n.

a wire that can be inserted into a bone to exert skeletal traction or to fix fractures. [M. Kirschner (1879–1942), German surgeon]

Back  -    New Search

kiss of life n.

see MOUTH-TO-MOUTH RESPIRATION.

Back  -    New Search

Klebsiella (kleb-si-el-) n.

a genus of Gram-negative rodlike nonmotile mostly lactose-fermenting bacteria found in the respiratory, intestinal, and urinogenital tracts of animals and man.

Back  -    New Search

Klebs-Loeffler bacillus (klebz-lerf-ler) n.

see CORYNEBACTERIUM. [T. Klebs (1834–1913) and F. A. J. Loeffler (1852–1915), German bacteriologists]

Back  -    New Search

Kleine-Levin syndrome (klyn-lev-in) n.

a rare episodic disorder characterized by periods (usually of a few days or weeks) in which sufferers eat enormously, sleep for most of the day and night, and may become more dependent or aggressive than normal. Between episodes they are usually quite unaffected. The disorder almost always resolves spontaneously. [W. Kleine (20th century), German neuropsychiatrist; M. Levin (20th century), US neurologist]

Back  -    New Search

klepto- prefix

denoting stealing.

Back  -    New Search

kleptomania (klept-may-ni) n.

a pathologically strong impulse to steal, often in the absence of any desire for the stolen object(s). It is sometimes associated with depression.

Back  -    New Search

Klinefelter's syndrome (klyn-fel-terz) n.

a genetic disorder in which there are three sex chromosomes, XXY, rather than the normal XX or XY. Affected individuals are apparently male, but have small testes, enlarged breasts, and absence of facial and body hair. [H. F. Klinefelter (1912– ), US physician]

Back  -    New Search

Klumpke's paralysis (kluump-kz) n.

a partial paralysis of the arm caused by injury to a baby's brachial plexus during birth. It results in weakness and wasting of the muscles of the hand. [A. Klumpke (1859–1927), French neurologist]

Back  -    New Search

kneading (need-ing) n.

see PETRISSAGE.

Back  -    New Search

knee (nee) n.

the hinge joint between the femur and the tibia. k.-chest position see GENUPECTORAL POSITION. k.-elbow position see GENUCUBITAL POSITION. k. jerk see PATELLAR REFLEX.

Back  -    New Search

kneecap (nee-kap) n.

see PATELLA.

Back  -    New Search

knock-knee (nok-nee) n.

abnormal incurving of the legs, resulting in a gap between the feet when the knees are in contact. Medical name: genu valgum .

Back  -    New Search

Kocher manoeuvre (kok-er) n.

a method for reduction of a dislocated shoulder by manipulation. [E. T. Kocher (1841–1917), Swiss surgeon]

Back  -    New Search

Koch's bacillus (koks) n.

see MYCOBACTERIUM. [R. Koch (1843–1910), German bacteriologist]

Back  -    New Search

Köhler's disease (ker-lerz) n.

necrosis of the navicular bone of the foot (see OSTEOCHONDRITIS). It occurs in children, causing pain and limping. [A. Köhler (1874–1947), German physician]

Back  -    New Search

koilonychia (koi-loh-nik-i) n.

the development of brittle spoon-shaped nails, a common disorder that can occur with anaemia due to iron deficiency.

Back  -    New Search

Koplik's spots (kop-liks) pl. n.

small red spots with bluish-white centres that often appear on the mucous membranes of the mouth in measles. [H. Koplik (1858–1927), US paediatrician]

Back  -    New Search

Korsakoff's syndrome (Korsakoff's psychosis) (kor-sak-offs) n.

an organic disorder affecting the brain that results in impaired memory for recent events, disorientation for time and place, and confabulation. The commonest cause of the condition is alcoholism, especially when this has led to deficiency of thiamin (vitamin B_1). [S. S. Korsakoff (1854–1900), Russian neurologist]

Back  -    New Search

kraurosis (kraw-roh-sis) n.

shrinking of a body part, usually the vulva in elderly women (k. vulvae ).

Back  -    New Search

Krebs cycle (citric acid cycle) (krebz) n.

a complex cycle of enzyme-catalysed reactions, occurring within the cells of all living animals, in which acetate is broken down to produce energy in the form of ATP and carbon dioxide. The cycle is the final step in the oxidation of carbohydrates, fats, and proteins. [Sir H. A. Krebs (1900–81), German-born biochemist]

Back  -    New Search

Krukenberg tumour (kroo-kn-berg) n.

a rapidly developing malignant growth in one or (more often) both ovaries. The tumour is secondary to a primary growth in the stomach or intestine. [F. E. Krukenberg (1871–1946), German pathologist]

Back  -    New Search

krypton-81m (krip-ton) n.

a radioactive gas that is the shortest-lived isotope in medical use (half-life 13 seconds). It can be used to investigate the function of the lungs. See also RUBIDIUM-81.

Back  -    New Search

Küntscher nail (koont-sher) n.

a long steel nail that is inserted down the long axis of a long bone, into the marrow, in order to fix a fracture. [G. Küntscher (1902–72), German orthopaedic surgeon]

Back  -    New Search

Kupffer cells (kuup-fer) pl. n.

phagocytic cells that line the sinusoids of the liver (see MACROPHAGE). They are particularly concerned with the formation of bile. [K. W. von Kupffer (1829–1902), German anatomist]

Back  -    New Search

Kussmaul breathing (koos-mowl) n.

the slow deep respiration associated with acidosis. [A. Kussmaul (1822–1902), German physician]

Back  -    New Search

Kveim test (kvaym) n.

a test used for the diagnosis of sarcoidosis. Tissue from a lymph node of a person suffering from the disease is injected intradermally; the development of a granuloma at the injection site indicates that the subject has sarcoidosis. [M. A. Kveim (20th century), Norwegian physician]

Back  -    New Search

kwashiorkor (kwash-i-or-ker) n.

a form of malnutrition due to a diet deficient in protein and energy-producing foods, common among young children in certain African tribes. The symptoms are oedema, loss of appetite, diarrhoea, general discomfort, and apathy; the child fails to thrive and there is usually associated gastrointestinal infection.

Back  -    New Search

kymograph (ky-m-grahf) n.

an instrument for recording the flow and varying pressure of the blood within blood vessels.
—kymography n.

Back  -    New Search

kypho- prefix

denoting a hump.

Back  -    New Search

kyphos (ky-fos) n.

a sharply localized forward angulation of the spine, resulting in the appearance of a lump (the deformity of the traditional hunchback).

Back  -    New Search

kyphoscoliosis (ky-foh-skoh-li-oh-sis) n.

abnormal curvature of the spine both forwards and sideways: kyphosis combined with scoliosis.

Back  -    New Search

kyphosis (ky-foh-sis) n.

excessive outward curvature of the spine, causing hunching of the back. It may result from bad posture or muscle weakness (mobile k. ) or from diseases such as osteochondritis or ankylosing spondylitis (fixed k. ).
Treatment depends on the cause, and may include physiotherapy, bracing, and spinal osteotomy in severe cases. See also KYPHOS, KYPHOSCOLIOSIS.

Back  -    New Search

L

labetalol (la-bee-t-lol) n.

a combined alpha- and beta-blocking drug (see SYMPATHOLYTIC), sometimes found to be more effective in the treatment of high blood pressure than beta blockers. It is administered by mouth or intravenous infusion. Trade names: Labrocol , Trandate .

Back  -    New Search

labial (lay-bi-l) adj.

1 relating to the lips or to a labium.

2 designating the surface of a tooth adjacent to the lips.
Top

Back  -    New Search

labile (lay-byl) adj.

unstable. The term is applied to drugs and other chemicals that readily undergo change in solution, when subjected to heat, etc., and also to emotions when there are rapid mood swings.

Back  -    New Search

labio- prefix

denoting the lip(s).

Back  -    New Search

labioplasty (cheiloplasty) (lay-bi-oh-plasti) n.

surgical repair of injury or deformity of the lips (cleft lip).

Back  -    New Search

labium (lay-bi-m) n. (pl. labia)

a lip-shaped structure, especially either of the two pairs of skin folds that enclose the vulva. The larger outer pair are known as the labia majora and the smaller inner pair the labia minora (or nymphae ).

Back  -    New Search

labour (lay-ber) n.

the sequence of actions by which a baby and the afterbirth (placenta) are expelled from the uterus at childbirth (see illustration). Labour usually starts spontaneously about 280 days after conception, but it may be started by artificial means (see INDUCTION). In the first stage the muscular wall of the uterus begins contracting while the cervix expands. The amnion ruptures releasing amniotic fluid to the exterior. In the second stage the baby passes through the vagina, assisted by contractions of the abdominal muscles and conscious pushing by the mother. When the whole infant has been eased clear of the vagina, the umbilical cord is cut. In the final stage the placenta and membranes are pushed out by the continuing contraction of the uterus. See also CAESAREAN SECTION.

Back  -    New Search

labrum (lay-brm) n. (pl. labra)

a lip or lip-like structure; occurring, for example, around the margins of the acetabulum.

Back  -    New Search

labyrinth (inner ear) (lab-er-inth) n.

a convoluted system of cavities and ducts comprising the organs of hearing and balance. bony l. the bony canals and chambers, embedded in the petrous part of the temporal bone, that surround the membranous labyrinth. membranous l. the membranous canals and chambers comprising the semicircular canals, utricle, saccule, and cochlea.

Back  -    New Search

labyrinthectomy (lab-er-inth-ek-tmi) n.

a surgical procedure to ablate (see ABLATION) the structures of the labyrinth, usually performed for cases of severe Ménière's disease.

Back  -    New Search

labyrinthitis (lab-er-inth-l-tis) n.

see OTITIS (INTERNA).

Back  -    New Search

laceration (las-er-ay-shn) n.

a tear in the flesh producing a wound with irregular edges.

Back  -    New Search

lacrimal (lak-rim-l) adj.

relating to tears. l. apparatus the structures that produce and drain away fluid from the eye (see illustration). l. bone either of a pair of small rectangular bones that contribute to the orbits. l. gland the gland that secretes tears, which drain away through small openings (puncta ) at the inner corner of the eye. l. nerve a branch of the ophthalmic nerve that supplies the lacrimal gland and conjunctiva.

Back  -    New Search

lacrimation (lak-ri-may-shn) n.

the production of excess tears; crying.

Back  -    New Search

lacrimator (lak-rim-ay-ter) n.

an agent that irritates the eyes, causing excessive secretion of tears.

Back  -    New Search

lact- (lacti-, lacto-) prefix

denoting 1 milk.

2 lactic acid.
Top

Back  -    New Search

lactalbumin (lak-tal-bew-min) n.

a milk protein present in milk at a lower concentration than casein.

Back  -    New Search

lactase (lak-tayz) n.

an enzyme, secreted by the glands of the small intestine, that converts lactose (milk sugar) into glucose and galactose during digestion.

Back  -    New Search

lactate (lak-tayt)

1 n. any salt of lactic acid.

2 vb. to secrete milk (see LACTATION).
Top

Back  -    New Search

lactation (lak-tay-shn) n.

the secretion of milk by the mammary glands of the breasts, which usually begins at the end of pregnancy (see also COLOSTRUM) and is stimulated by the sucking of the baby at the nipple. Lactation is controlled by hormones (see PROLACTIN, OXYTOCIN); it stops when the baby is no longer breast-fed.

Back  -    New Search

lacteal (lak-ti-l) n.

a blind-ended lymphatic vessel that extends into a villus of the small intestine. Digested fats are absorbed into the lacteals.

Back  -    New Search

lactic acid (lak-tik) n.

a compound that forms in the cells as the end-product of glucose metabolism in the absence of oxygen (see GLYCOLYSIS). Lactic acid (owing to its low pH) is an important food preservative.

Back  -    New Search

lactiferous (lak-tif-er-s) adj.

transporting or secreting milk, as the ducts (l. ducts ) of the breast.

Back  -    New Search

lactifuge (lak-ti-fewj) n.

a drug that reduces the secretion of milk. Some oestrogenic drugs have this effect.

Back  -    New Search

Lactobacillus (lak-toh-b-sil-s) n.

a genus of Gram-positive nonmotile rodlike bacteria that are capable of producing lactic acid from the fermentation of carbohydrates. They are found in fermenting animal and plant products, especially dairy products, and in the alimentary tract and vagina.

Back  -    New Search

lactogenic hormone (lak-t-jen-ik) n.

see PROLACTIN.

Back  -    New Search

lactometer (lak-tom-it-er) n.

an instrument for measuring the relative density (specific gravity) of milk.

Back  -    New Search

lactose (milk sugar) (lak-tohz) n.

a sugar, consisting of one molecule of glucose and one of galactose, found only in milk. l. intolerance inability to absorb lactose, caused by absence or low activity of the enzyme lactase.

Back  -    New Search

lactosuria (lak-tohs-yoor-i) n.

the presence of lactose in the urine. This often occurs during pregnancy and breast-feeding or if the milk flow is suppressed.

Back  -    New Search

lactulose (lak-tew-lohz) n.

a disaccharide sugar that acts as a laxative. Administered by mouth, it remains intact until it reaches the colon. There it is split by bacteria into simpler sugars that help to retain water, thereby softening the stools. Trade names: Duphalac , Lactulose .

Back  -    New Search

lacuna (l-kew-n) n. (pl. lacunae)

(in anatomy) a small cavity or depression.

Back  -    New Search

Laënnec's cirrhosis (la-en-neks) n.

alcoholic cirrhosis: the commonest type of cirrhosis. [R. T. H. Laënnec (1781–1826), French physician]

Back  -    New Search

laevo- prefix

see LEVO-.

Back  -    New Search

laevocardia (lee-voh-kar-di-) n.

the normal position of the heart, in which its apex is directed towards the left. Compare DEXTROCARDIA.

Back  -    New Search

laking (layk-ing) n.

the physical or chemical treatment of blood to abolish the structure of the red cells and thus form a homogeneous solution. Laking is an important preliminary step in the analysis of haemoglobin or enzymes present in red cells.

Back  -    New Search

-lalia suffix

denoting a condition involving speech.

Back  -    New Search

lallation (lalling) (la-lay-shn) n.

1 unintelligible speechlike babbling, as heard from infants.

2 the immature substitution of one consonant for another (e.g. ‘l’ for ‘r’).
Top

Back  -    New Search

lambda (lam-d) n.

the point on the skull at which the lambdoidal and sagittal sutures meet.

Back  -    New Search

lambdoidal suture (lam-doi-d'l) n.

the immovable joint between the parietal and occipital bones (see SKULL).

Back  -    New Search

lambliasis (lam-bly--sis) n.

see GIARDIASIS.

Back  -    New Search

lamella (l-mel-) n. (pl. lamellae)

1 a thin layer, membrane, scale, or platelike tissue or part.

2 a thin gelatinous medicated disc used to apply drugs to the eye. The disc is placed on the eyeball; the gelatinous material dissolves and the drug is absorbed.
Top

Back  -    New Search

lamina (lam-in-) n. (pl. laminae)

a thin membrane or layer of tissue.

Back  -    New Search

laminectomy (lam-in-ek-tmi) n.

surgical cutting into the backbone to obtain access to the spinal cord. The operation is performed to remove tumours or prolapsed intervertebral discs or to relieve pressure on the spinal cord or roots.

Back  -    New Search

lamotrigine (lam-oh-try-geen) n.

an anti-convulsant drug used in the control of epilepsy. Lamotrigine is administered by mouth. Trade name: Lamictal .

Back  -    New Search

lanatoside (l-nat-oh-syd) n.

a drug similar to digitalis, administered by mouth or injection in the treatment of heart failure. Trade name: Cedilanid .

Back  -    New Search

Lancefield classification (lans-feeld) n.

a classification of the Streptococcus bacteria based on the presence or absence of antigenic carbohydrate on the cell surface. Species are classified into the groups A-S. Most species causing disease in man belong to groups A, B, and D. [R. C. Lancefield (1895–1981), US bacteriologist]

Back  -    New Search

lancet (lahn-sit) n.

a broad two-edged surgical knife with a sharp point.

Back  -    New Search

lancinating (lahn-sin-ayt-ing) adj.

describing a sharp stabbing or cutting pain.

Back  -    New Search

Landry's paralysis (lahn-dreez) n.

a rapidly progressive form of the Guillain-Barré syndrome. [J. B. O. Landry (1826–65), French physician]

Back  -    New Search

Lange curve (lahng-) n.

an obsolescent method of detecting excess globulins in the protein of the cerebrospinal fluid. It was useful in the diagnosis of neurosyphilis and multiple sclerosis but has been superseded by more specific tests. [F. A. Lange (20th century), German physician]

Back  -    New Search

Langer's lines (lahng-erz) pl. n.

normal permanent skin creases. Incisions parallel to Langer's lines heal well and are less visible. [C. R. von E. Langer (1819–87), Austrian anatomist]

Back  -    New Search

lanolin (lan--lin) n.

a fatty substance obtained from sheep's wool, used as an emollient and as a base for ointments.

Back  -    New Search

lanugo (l-new-goh) n.

fine hair covering the body and limbs of the human fetus.

Back  -    New Search

laparo- prefix

denoting the loins or abdomen.

Back  -    New Search

laparoscope (peritoneoscope) (lap-er--skohp) n.

see LAPAROSCOPY.

Back  -    New Search

laparoscopy (abdominoscopy, peritoneoscopy) (lap-er-os-kpi) n.

examination of the abdominal structures by means of an illuminated tubular instrument (laparoscope ). This is passed through a small incision in the wall of the abdomen after injecting carbon dioxide into the abdomen (pneumoperitoneum). In addition to being a diagnostic aid, it is used when taking a biopsy, aspirating cysts, and dividing adhesions. Surgery, including cholecystectomy, colectomy, and the occlusion of Fallopian tubes for sterilization, can also be performed through a laparoscope, using either a laser or diathermy to control bleeding (see also MINIMALLY INVASIVE SURGERY). laser l. surgery performed through a laparoscope using a laser: used, for example, for collecting ova for in vitro fertilization.
—laparoscopic adj.

Back  -    New Search

laparotomy (lap-er-ot-mi) n.

a surgical incision into the abdominal cavity. The operation is done to examine the abdominal organs as a help to diagnosis.

Back  -    New Search

lardaceous (lar-day-shs) adj.

resembling lard: often applied to tissue infiltrated with the starchlike substance amyloid (see AMYLOIDOSIS).

Back  -    New Search

Lariam (la-ri-am) n.

see MEFLOQUINE.

Back  -    New Search

larva (lar-v) n. (pl. larvae)

the preadult or immature stage hatching from the egg of some animal groups, e.g. insects and nematodes, which may be markedly different from the sexually mature adult. l. migrans see CREEPING ERUPTION.
—larval adj.

Back  -    New Search

laryng- (laryngo-) prefix

denoting the larynx.

Back  -    New Search

laryngeal (la-rin-jee-l) adj.

relating to the larynx. l. reflex a cough produced by irritating the larynx. l. stroboscopy a method of studying the movements of the vocal folds of the larynx by using stroboscopic light (controlled intermittent flashes) to slow or freeze the movement.

Back  -    New Search

laryngectomy (la-rin-jek-tmi) n.

surgical removal of the whole or a part of the larynx.

Back  -    New Search

laryngismus (la-rin-jiz-ms) n.

closure of the vocal folds by sudden contraction of the laryngeal muscles, followed by a noisy indrawing of breath. It occurs in young children when a foreign body has lodged in the larynx or in croup; in the past it was associated with low-calcium rickets.

Back  -    New Search

laryngitis (la-rin-jy-tis) n.

inflammation of the larynx and vocal folds, due to infection or irritation. The voice becomes husky or is lost completely; breathing is harsh and difficult (see STRIDOR); and the cough is painful. Obstruction of the airways may occasionally be serious, especially in children (see CROUP).

Back  -    New Search

laryngofissure (l-ring-oh-fish-er) n.

a surgical operation to open the larynx, enabling access for further procedures.

Back  -    New Search

laryngology (la-ring-ol-ji) n.

the study of diseases of the larynx and vocal folds.
—laryngologist n.

Back  -    New Search

laryngomalacia (l-ring-oh-m-lay-shi) n.

a condition characterized by paroxysmal attacks of breathing difficulty and stridor. It occurs in small children and is caused by flaccidity of the structure of the larynx. It usually resolves spontaneously by the age of two years.

Back  -    New Search

laryngopharynx (hypopharynx) (l-ring-oh-fa-rinks) n.

the part of the pharynx that lies below the hyoid bone.

Back  -    New Search

laryngoscope (l-ring--skohp) n.

an instrument (a type of endoscope) for examining the larynx. See LARYNGOSCOPY.

Back  -    New Search

laryngoscopy (la-ring-os-kpi) n.

examination of the larynx. This may be done indirectly using a small mirror or directly using a laryngoscope.

Back  -    New Search

laryngospasm (l-ring-oh-spazm) n.

involuntary closure of the larynx, obstructing the flow of air to the lungs.

Back  -    New Search

laryngostenosis (l-ring-oh-sti-noh-sis) n.

narrowing of the cavity of the larynx.

Back  -    New Search

laryngotomy (la-ring-ot-mi) n.

surgical incision of the larynx. inferior l. surgical incision of the cricothyroid membrane beneath the larynx; a life-saving operation when there is obstruction to breathing at or above the larynx. See TRACHEOSTOMY.

Back  -    New Search

laryngotracheobronchitis (l-ring-oh-trak-i-oh-brong-ky-tis) n.

a severe and almost exclusively viral infection of the respiratory tract, especially of young children, in whom there may be a dangerous degree of obstruction either at the larynx (see CROUP) or bronchi.

Back  -    New Search

larynx (la-rinks) n.

the organ responsible for the production of vocal sounds, also serving as an air passage conveying air from the pharynx to the lungs. It is situated in the front of the neck, above the trachea. It is made up of a framework of nine cartilages, bound together by ligaments and muscles and lined with mucous membrane, and contains a pair of vocal folds.

—laryngeal adj.

Back  -    New Search

laser (lay-zer) n.

a device that produces a very thin beam of light in which high energies are concentrated. In surgery, lasers can be used to operate on small areas of abnormality without damaging delicate surrounding tissue. They are used in eye surgery for cutting tissue (YAG l. ), for photocoagulation of the retina (argon l. , diode l. ), and in operations on the cornea for correcting myopia (excimer l. ). Lasers are also used to unblock coronary arteries narrowed by atheroma, to remove certain types of birthmark (see NAEVUS), and in the treatment of cervical intraepithelial neoplasia (CIN).

Back  -    New Search

laser laparoscopy n.

see LAPAROSCOPY.

Back  -    New Search

Lasix (las-iks) n.

see FRUSEMIDE.

Back  -    New Search

Lassa fever (las-) n.

a serious virus disease confined to Central West Africa. Symptoms include headache, high fever, and severe muscular pains; difficulty in swallowing often arises. Death from kidney or heart failure occurs in over 50% of cases. Treatment with plasma from recovered patients is the best therapy.

Back  -    New Search

Lassar's paste (las-arz) n.

an ointment containing zinc oxide, starch, and salicylic acid in a soft paraffin base, used in the treatment of eczema and similar skin diseases. [G. Lassar (1849–1907), German dermatologist]

Back  -    New Search

latamoxef (lat--moks-ef) n.

a cephalosporin antibiotic active against many Gram-negative bacilli (see GRAM'S STAIN). Trade name: Moxalactam .

Back  -    New Search

latent heat (lay-tnt) n.

the quantity of heat absorbed or released when a substance changes state (e.g. from solid to liquid or from liquid to vapour) without any change in temperature.

Back  -    New Search

lateral (lat-er-l) adj.

1 situated at or relating to the side of an organ or organism.

2 (in anatomy) relating to the region or parts of the body that are furthest from the median plane.
Top

3 (in radiology) in the sagittal plane.
Top

Back  -    New Search

lateroversion (lat-er-oh-ver-shn) n.

a turning or displacement of an organ, for example the uterus (uterine l. ), to one side.

Back  -    New Search

laudanum (lawd-nm) n.

a hydroalcoholic solution containing 1% morphine, prepared from macerated raw opium. It was formerly widely used as a narcotic analgesic, taken by mouth.

Back  -    New Search

laughing gas (lahf-ing) n.

see NITROUS OXIDE.

Back  -    New Search

lavage (lav-ahzh) n.

washing out a body cavity, such as the colon or stomach, with water or a medicated solution. In cases of bowel obstruction the washing out can be done during the operation (on-table l. ). See also BRONCHOALVEOLAR LAVAGE.

Back  -    New Search

laxative (laks--tiv) n.

a drug used to stimulate or increase the frequency of bowel evacuation (cathartics or purgatives ; e.g. castor oil, senna, magnesium sulphate) or to encourage a softer or bulkier stool (bulking agents ; e.g. methylcellulose).

Back  -    New Search

LDL n. low-density lipoprotein:

see LIPOPROTEIN.

Back  -    New Search

L-dopa n.

see LEVODOPA.

Back  -    New Search

lead (led) n.

a soft bluish-grey metallic element that forms several poisonous compounds. Acute lead poisoning causes abdominal pains, vomiting, diarrhoea, and sometimes encephalitis. In chronic poisoning a characteristic blue mark on the gums (l. line ) is seen and the peripheral nerves are affected; there is also anaemia. Treatment is with edetate. The use of lead in paints is now strictly controlled. Symbol: Pb.

Back  -    New Search

learning disability (learning difficulty) (lern-ing) n.

see MENTAL HANDICAP.

Back  -    New Search

leather-bottle stomach (leth-er bot-t'l) n.

see LINITIS PLASTICA.

Back  -    New Search

Leber's congenital amaurosis (lay-berz) n.

a hereditary disease (inherited as an autosomal recessive inherited condition) causing severe visual loss in infants. [T. Leber (1840–1917), German ophthalmologist]

Back  -    New Search

Leber's optic atrophy n.

a rare hereditary disorder, affecting young males, that is characterized by rapid loss of central vision due to neuroretinal degeneration.

Back  -    New Search

LE cells pl. n.

see LUPUS (ERYTHEMATOSUS).

Back  -    New Search

lecithin (les-i-thin) n.

one of a group of phospholipids that are important constituents of cell membranes and are involved in the metabolism of fat by the liver. An example is phosphatidylcholine. l.-sphingomyelin ratio (LS ratio ) a measure of fetal lung maturity; an LS ratio below 2 indicates a higher risk of respiratory distress syndrome.

Back  -    New Search

lecithinase (les-i-thin-ayz) n.

an enzyme from the small intestine that breaks lecithin down into its constituents (i.e. glycerol, fatty acids, phosphoric acid, and choline).

Back  -    New Search

leech (leech) n.

a type of worm that possesses suckers at both ends of its body. Certain parasitic species suck blood from animals and man, causing irritation and, occasionally, infection. Formerly widely used for bloodletting, the medicinal leech (Hirudo medicinalis) may now be used following microsurgery to restore patency to blocked or collapsed blood vessels.

Back  -    New Search

Legg-Calvé-Perthes disease (Perthes disease, pseudocoxalgia) (leg kal-vay per-tz) n.

necrosis of the head of the femur due to interruption of its blood supply (see OSTEOCHONDRITIS). It occurs most commonly in boys between the ages of 5 and 10, and causes aching and a limp. [A. T. Legg (1874–1939), US surgeon; J. Calvé (1875–1954), French orthopaedist; G. C. Perthes (1869–1927), German surgeon]

Back  -    New Search

legionnaires' disease (lee-jn-airz) n.

an infection of the lungs caused by the bacterium Legionella pneumophila. Symptoms include malaise and muscle pain, succeeded by a fever, dry cough, chest pain, and breathlessness. Erythromycin provides the most effective therapy.

Back  -    New Search

legumin (lig-yoo-min) n.

a protein (a globulin) obtained from the seeds of plants of the family Leguminosae, such as beans and peas.

Back  -    New Search

leio- prefix

denoting smoothness.

Back  -    New Search

leiomyoma (ly-oh-my-oh-m) n.

a benign tumour of smooth muscle. Such tumours occur most commonly in the uterus (see FIBROID) but can also arise in the digestive tract, walls of blood vessels, etc.

Back  -    New Search

leiomyosarcoma (ly-oh-my-oh-sar-koh-m) n.

a malignant tumour of smooth muscle, most commonly found in the womb, stomach, small bowel, and at the base of the bladder.

Back  -    New Search

Leishman-Donovan body (leesh-mn don--vn) n.

see LEISHMANIA. [Sir W. B. Leishman (1865–1926), British surgeon; C. Donovan (1863–1951), Irish physician]

Back  -    New Search

Leishmania (leesh-may-ni) n.

a genus of parasitic flagellate protozoans, several species of which cause disease in man (see LEISHMANIASIS). In man, especially in kalaazar patients, the parasite is a small rounded structure called a Leishman-Donovan body , which is found within the cells of the lymphatic system, spleen, and bone marrow.

Back  -    New Search

leishmaniasis (leesh-m-ny--sis) n.

a disease, common in the tropics and subtropics, caused by parasitic protozoans of the genus Leishmania, which are transmitted by the bite of sandflies. cutaneous l. leishmaniasis that affects the tissues of the skin. See ESPUNDIA, ORIENTAL SORE. visceral l. leishmaniasis in which the cells of various internal organs are affected. See KALA-AZAR.

Back  -    New Search

Lembert's suture (lahm-bairz) n.

a suture used for closing wounds in the intestine in which the edges are turned inwards and stitched down to the level of the submucosa. [A. Lembert (1802–51), French surgeon]

Back  -    New Search

lens (lenz) n.

1 (in anatomy) the transparent crystalline structure situated behind the pupil of the eye. It helps to refract incoming light and focus it onto the retina. See also ACCOMMODATION.

2 (in optics) a piece of glass or other material shaped to refract rays of light in a particular direction. Lenses are worn to correct faulty eyesight. l. implant a plastic lens to replace a natural lens that has been removed because of cataract. See also BIFOCAL LENSES, CONTACT LENSES, MULTIFOCAL LENSES.
Top

Back  -    New Search

lenticular (len-tik-yoo-ler) adj.

relating to or shaped like a lens.

Back  -    New Search

lenticular nucleus (lentiform nucleus) n.

see BASAL GANGLIA.

Back  -    New Search

lentigo (len-ty-goh) n. (pl. lentigines)

a flat dark brown spot found mainly in the elderly on skin exposed to light. l. maligna (Hutchinson's l. ) a form of lentigo that occurs on the cheeks of the elderly. The spot is larger than 2 cm in diameter and has variable pigmentation; it is an early malignant melanoma that has not spread deeply.

Back  -    New Search

leontiasis (lee-on-ty--sis) n.

overgrowth of the skull bones, said to resemble the appearance of a lion's head: it is a rare feature of untreated Paget's disease. Medical name: leontiasis ossea .

Back  -    New Search

leproma (lep-roh-m) n.

a lump on the skin characteristic of leprosy.

Back  -    New Search

leprosy (Hansen's disease) (lep-r-si) n.

a chronic disease, caused by the bacterium Mycobacterium leprae, that affects the skin, mucous membranes, and nerves. It is confined mainly to the tropics and is transmitted by direct contact. Symptoms mainly involve the skin and nerves. Leprosy should be treated with a combination of antibacterial drugs (including dapsone and rifampicin), to overcome the problem of resistance developing to a single drug, and reconstructive surgery can repair some of the damage caused by the disease. indeterminate l. a form of the disease in which the skin manifestations represent a combination of lepromatous and tuberculoid leprosy. lepromatous (or multibacillary ) l. a contagious steadily progressive form of the disease characterized by the development of widely distributed lumps on the skin, thickening of the skin and nerves, and in serious cases by severe numbness of the skin, muscle weakness, and paralysis leading to disfigurement and deformity. Tuberculosis is a common complication. paucibacillary l. tuberculoid or indeterminate leprosy. tuberculoid l. a benign, often self-limiting, form of leprosy causing discoloration and disfiguration of patches of skin associated with localized numbness.

Back  -    New Search

lept- (lepto-) prefix

denoting 1 slender; thin.

2 small.
Top

3 mild; slight.
Top

Back  -    New Search

leptin (lep-tin) n.

a protein, produced by white fat cells in adipose tissue, that acts on the brain and is involved in controlling the amount of white adipose tissue laid down in the body.

Back  -    New Search

leptocyte (lep-toh-syt) n.

a red blood cell (erythrocyte) that is abnormally thin. Leptocytes are seen in certain types of anaemia.

Back  -    New Search

leptomeninges (lep-toh-min-in-jeez) pl. n.

the inner two meninges: the arachnoid and pia mater.

Back  -    New Search

leptomeningitis (lep-toh-men-in-jy-tis) n.

inflammation of the leptomeninges. See also MENINGITIS.

Back  -    New Search

Leptospira (lep-toh-spy-r) n.

a genus of spirochaete bacteria, commonly bearing hooked ends. L. icterohaemorrhagiae a parasite that is the main causative agent of leptospirosis.

Back  -    New Search

leptospirosis (Weil's disease) (lep-toh-spy-roh-sis) n.

an infectious disease, caused by bacteria of the genus Leptospira (especially L. icterohaemorrhagiae), that is transmitted from rodents, dogs, and other mammals to man. The disease begins with a high fever and headache and may affect the liver (causing jaundice) or kidneys (resulting in renal failure); in some cases meningitis may develop.

Back  -    New Search

leresis (ler-ee-sis) n.

rambling speech, immature both in syntax and pronunciation. It is a feature of dementia.

Back  -    New Search

Leriche's syndrome (l-reesh-z) n.

a condition in males characterized by absence of penile erection combined with absence of pulses in the femoral arteries and wasting of the buttock muscles. It is caused by occlusion of the abdominal aorta and iliac arteries. [R. Leriche (1879–1956), French surgeon]

Back  -    New Search

lesbianism (lez-bi-n-izm) n.

female homosexuality: the condition in which a woman is sexually attracted to, or engages in sexual behaviour with, another woman.
—lesbian adj., n.

Back  -    New Search

Lesch-Nyhan disease (lesh-ny-hn) n.

a sex-linked hereditary disease caused by an enzyme deficiency resulting in overproduction of uric acid. Affected boys are mentally retarded and suffer from spasticity and gouty arthritis. They also have a compulsion for self-mutilation. [M. Lesch (1939– ) and W. L. Nyhan Jr. (1926– ), US physicians]

Back  -    New Search

lesion (lee-zhn) n.

a zone of tissue with impaired function as a result of damage by disease or wounding.

Back  -    New Search

lethal gene (lee-thl) n.

a gene that, under certain conditions, causes the death of the individual carrying it. Lethal genes are usually recessive: an individual will die only if both his parents carry the gene.

Back  -    New Search

lethargy (leth-er-ji) n.

mental and physical sluggishness: a degree of inactivity and unresponsiveness approaching or verging on the unconscious.

Back  -    New Search

Letterer-Siwe disease (let-er-er sy-w) n.

see RETICULOENDOTHELIOSIS. [E. Letterer (20th century) and S. A. Siwe (1897–1966), German physicians]

Back  -    New Search

leuc-(leuco-, leuk-, leuko-) prefix

denoting 1 lack of colour; white.

2 leucocytes.
Top

Back  -    New Search

leucine (loo-seen) n.

an essential amino acid. See also AMINO ACID.

Back  -    New Search

leucocidin (loo-koh-sy-din) n.

a bacterial exotoxin that selectively destroys white blood cells (leucocytes).

Back  -    New Search

leucocyte (white blood cell) (loo-k-syt) n.

any blood cell that contains a nucleus. In health there are three major subdivisions: granulocytes, lymphocytes, and monocytes, which are involved in protecting the body against foreign substances and in antibody production. In disease, a variety of other types may appear in the blood.

Back  -    New Search

leucocytolysis (loo-koh-sy-tol-i-sis) n.

destruction of white blood cells.

Back  -    New Search

leucocytosis (loo-koh-sy-toh-sis) n.

an increase in the number of leucocytes in the blood. See BASOPHILIA, EOSINOPHILIA, LYMPHOCYTOSIS, MONOCYTOSIS.

Back  -    New Search

leucocytospermia (loo-koh-sy-toh-sperm-i) n.

the presence of excess white blood cells (leucocytes) in the semen (more than 1 million/ml). It has an adverse effect on fertility.

Back  -    New Search

leucoderma (loo-koh-der-m) n.

loss of pigment in areas of the skin, resulting in the appearance of white patches or bands.

Back  -    New Search

leucolysin (loo-kol-i-sin) n.

see LYSIN.

Back  -    New Search

leucoma (loo-koh-m) n.

a white opacity in the cornea. Most leucomas result from scarring after corneal inflammation or ulceration.

Back  -    New Search

leuconychia (loo-koh-nik-i) n.

white discoloration of the nails, which may be total or partial. The cause is unknown.

Back  -    New Search

leucopenia (loo-koh-pee-ni) n.

a reduction in the number of leucocytes in the blood. See EOSINOPENIA, LYMPHOPENIA, NEUTROPENIA.

Back  -    New Search

leucoplakia (leukoplakia) (loo-koh-play-ki) n.

a thickened white patch on a mucous membrane, such as the mouth lining or vulva, that cannot be rubbed off. Occasionally leucoplakia can become malignant. hairy l. leucoplakia with a shaggy or hairy appearance, which is a marker of AIDS.

Back  -    New Search

leucopoiesis (loo-koh-poi-ee-sis) n.

the process of the production of leucocytes, which normally occurs in the blood-forming tissue of the bone marrow. See also GRANULOPOIESIS, HAEMOPOIESIS, LYMPHOPOIESIS, MONOBLAST.

Back  -    New Search

leucorrhoea (loo-k-ree-) n.

a whitish or yellowish discharge of mucus from the vaginal opening. An abnormally large discharge may indicate infection of the lower reproductive tract.

Back  -    New Search

leucotomy (loo-kot-mi) n.

the surgical operation of interrupting the pathways of white nerve fibres within the brain: it involves stereotaxy to make selective lesions in small areas of the brain. The operation is occasionally used for intractable pain, severe depression, obsessional neurosis, and chronic anxiety. prefrontal l. (lobotomy) the original form of the operation, which involved cutting through the nerve fibres connecting the frontal lobe with the thalamus and the association fibres of the frontal lobe; it has now been abandoned.

Back  -    New Search

leukaemia (loo-kee-mi) n.

any of a group of malignant diseases in which increased numbers of certain immature or abnormal leucocytes are produced. This leads to increased susceptibility to infection, anaemia, and bleeding. Other symptoms include enlargement of the spleen, liver, and lymph nodes. Leukaemias may be acute or chronic depending on the rate of progression of the disease. They are also classified according to the type of white cell that is proliferating abnormally (see HAIRY CELL, LYMPHOBLAST, MYELOBLAST, MYELOID (LEUKAEMIA)). Leukaemias are treated with radiotherapy or cytotoxic drugs.

Back  -    New Search

leukoplakia (loo-koh-play-ki) n.

see LEUCOPLAKIA.

Back  -    New Search

leuprorelin (loo-proh-rel-in) n.

see LHRH ANALOGUE.

Back  -    New Search

levallorphan (lev--lor-fan) n.

a drug that counteracts the depression in breathing caused by narcotic analgesics such as morphine without affecting their pain-relieving effects. It is administered by injection. Trade name: Lorfan .

Back  -    New Search

levator (li-vay-ter) n.

1 a surgical instrument used for levering up displaced bone fragments in a depressed fracture of the skull.

2 any muscle that lifts the structure into which it is inserted.
Top

Back  -    New Search

levo (laevo-) prefix

denoting 1 the left side.

2 (in chemistry) levorotation.
Top

Back  -    New Search

levodopa (L-dopa) (lee-voh-doh-p) n.

a naturally occurring amino acid (see DOPA) administered by mouth to treat parkinsonism. Trade names: Brocadopa , Larodopa .

Back  -    New Search

levonorgestrel (lee-voh-nor-jes-trl) n.

a synthetic female sex hormone – a progestogen – used mainly in oral contraceptives, either in combination with an oestrogen or as a progestogen-only preparation. Capsules may be implanted in the upper arm. Trade names: Microval , Norgeston , Norplant .

Back  -    New Search

levorphanol (li-vor-f-nol) n.

a narcotic analgesic, similar to morphine, administered by mouth or injection to relieve severe pain. Trade name: Dromoran .

Back  -    New Search

levulosuria (lev-yoo-lohs-yoor-i) n.

see FRUCTOSURIA.

Back  -    New Search

Leydig cells (ly-dig) pl. n.

see INTERSTITIAL CELLS. [F. von Leydig (1821–1908), German anatomist]

Back  -    New Search

Leydig tumour n.

a tumour of the interstitial (Leydig) cells of the testis. Such tumours often secrete testosterone, which in prepubertal boys causes virilization.

Back  -    New Search

LH n.

see LUTEINIZING HORMONE.

Back  -    New Search

Lhermitte's sign (lair-mits) n.

a tingling shocklike sensation passing down the arms or trunk when the neck is flexed. It is a nonspecific indication of disease in the cervical (neck) region of the spinal cord. [J. Lhermitte (1877–1959), French neurologist]

Back  -    New Search

LHRH analogue (GnRH analogue) n.

any one of a group of analogues of luteinizing hormone releasing hormone , which stimulates the release of luteinizing hormone from the pituitary gland (see also GONADOTROPHIN-RELEASING HORMONE). They are used in the treatment of endometriosis, fibroids, and some types of female infertility. Two LHRH analogues, goserelin (Zoladex) and leuprorelin (Prostap), are administered subcutaneously in the treatment of advanced prostate cancer.

Back  -    New Search

libido (lib-ee-doh) n.

the sexual drive: the term is often used to refer to the intensity of sexual desires. In psychoanalytic theory, the libido is said to be one of the fundamental sources of energy for all mental life.

Back  -    New Search

Librium (lib-rim) n.

see CHLORDIAZEPOXIDE.

Back  -    New Search

lice (lys) pl. n.

see LOUSE, PEDICULOSIS.

Back  -    New Search

lichen (ly-kn) n.

any of several types of skin disease. l. planus an extremely itchy skin disease of unknown cause. Shiny flattopped mauve spots may occur anywhere but are characteristically found on the inside of the wrists. It may take the form of a white lacy pattern in the mouth, which usually produces no symptoms. l. simplex chronicus (neurodermatitis) thickened eczematous skin that develops at the site of constant rubbing, often at the nape of the neck (in women) or lower legs (in men). l. sclerosus et atrophicus a chronic disease affecting the anogenital area, especially in women, and characterized by sheets of ivory-white skin.

Back  -    New Search

lichenification (ly-ken-i-fi-kay-shn) n.

thickening of the epidermis with exaggeration of the normal creases. The cause is abnormal scratching or rubbing of the skin.

Back  -    New Search

lichenoid (ly-kn-oid) adj.

describing any skin disease that resembles lichen planus.

Back  -    New Search

Lieberkühn's glands (crypts of Lieberkühn) (lee-ber-koonz) pl. n.

simple tubular glands in the mucous membrane of the intestine. They are lined with columnar epithelium in which various types of secretory cells are found. [J. N. Lieberkühn (1711–56), German anatomist]

Back  -    New Search

lien (ly-n) n.

see SPLEEN.

Back  -    New Search

lien- (lieno-) prefix

denoting the spleen.

Back  -    New Search

lienculus (ly-enk-yoo-ls) n.

an accessory spleen.

Back  -    New Search

ligament (lig--mnt) n.

1 a tough band of white fibrous connective tissue that links two bones together at a joint. Ligaments are inelastic but flexible; they strengthen the joint and limit its movements to certain directions.

2 a sheet of peritoneum that supports or links together abdominal organs.
Top

Back  -    New Search

ligation (li-gay-shn) n.

the application of a ligature.

Back  -    New Search

ligature (lig--cher) n.

any material – for example, nylon, silk, catgut, or wire – that is tied firmly round a blood vessel or duct to prevent bleeding, the passage of materials, etc.

Back  -    New Search

light adaptation (lyt) n.

reflex changes in the eye to enable vision either in normal light after being in darkness or in very bright light after being in normal light. See IRIS. Compare DARK ADAPTATION.

Back  -    New Search

lightening (ly-t'n-ing) n.

the sensation experienced, usually after the 36th week of gestation, by many pregnant women, particularly those carrying their first child, as the presenting part of the fetus enters the pelvis. This reduces the pressure on the diaphragm and the woman notices that it is easier to breathe. Compare ENGAGEMENT.

Back  -    New Search

lightning pains (lyt-ning) pl. n.

severe stabbing pains in the legs experienced in tabes dorsalis.

Back  -    New Search

light reflex n.

see PUPILLARY REFLEX.

Back  -    New Search

lignocaine (lig-n-kayn) n.

a widely used local anaesthetic administered by injection or by direct application to mucous membranes for minor surgery and dental procedures. For dental surgery it is normally used in combination with adrenaline. Lignocaine is also injected to treat conditions involving abnormal heart rhythm, particularly myocardial infarction. Trade names: Xylocaine , Xylocard .

Back  -    New Search

limbic system (lim-bik) n.

a complex system of nerve pathways and networks in the brain that is involved in the expression of instinct and mood in activities of the endocrine and motor systems of the body. Among the brain regions involved are the amygdala, hippocampal formation, and hypothalamus.

Back  -    New Search

limb lengthening (lim) n.

an orthopaedic procedure for increasing the length of a limb (usually the leg). It involves division of the bone and the use of an external fixator to widen the gap between the divided ends. New bone is produced in the widening gap as the bone is stretched.

Back  -    New Search

limbus (lim-bs) n.

(in anatomy) an edge or border. l. sclerae the junction of the cornea and sclera of the eye.

Back  -    New Search

limen (ly-men) n.

(in anatomy) a border or boundary.

Back  -    New Search

lime water (lym) n.

an aqueous solution of calcium hydroxide used in skin preparations, as an antacid, and as an astringent.

Back  -    New Search

liminal (lim-in-l) adj.

(in physiology) relating to the threshold of perception.

Back  -    New Search

linac (ly-nak) n.

see LINEAR ACCELERATOR.

Back  -    New Search

lincomycin (link-oh-my-sin) n.

an antibiotic administered by mouth or injection to treat infections, including osteomyelitis, that are caused by a narrow range of bacteria. Trade name: Lincocin .

Back  -    New Search

linctus (link-ts) n.

a syrupy liquid medicine, particularly one used in the treatment of irritating coughs.

Back  -    New Search

lindane (lin-dayn) n.

an insecticide drug applied as a lotion or cream to kill such parasites as lice and the scabies mite. Trade names: Esoderm , Lorexane .

Back  -    New Search

linea (lin-i) n. (pl. lineae)

(in anatomy) a line, narrow streak, or stripe. l. alba a tendinous line, extending from the xiphoid process to the pubic symphysis, where the flat abdominal muscles are attached. l. nigra a pigmented line, seen on the abdomen in pregnancy, extending from the umbilicus to the pubis.

Back  -    New Search

linear accelerator (linac) (lin-ier) n.

a machine that accelerates particles to produce high-energy radiation, used in the treatment (radiotherapy) of malignant disease.

Back  -    New Search

lingual (ling-wl) adj.

relating to, situated close to, or resembling the tongue (lingua).

Back  -    New Search

lingula (ling-yoo-l) n.

a thin tonguelike projection of bone or other tissue.

Back  -    New Search

liniment (lin-i-mnt) n.

a medicinal preparation that is rubbed onto the skin or applied on a surgical dressing. Liniments often contain camphor and alcohol.

Back  -    New Search

linitis plastica (leather-bottle stomach) (li-ny-tis plas-ti-k) n.

diffuse infiltration of the stomach submucosa with malignant tissue, producing rigidity and narrowing.

Back  -    New Search

linoleic acid (lin-oh-lee-ik) n.

see ESSENTIAL FATTY ACID.

Back  -    New Search

linolenic acid (lin-oh-len-ik) n.

see ESSENTIAL FATTY ACID.

Back  -    New Search

lint (lint) n.

a material used in surgical dressings, made of scraped linen or a cotton substitute. It is usually fluffy one side and smooth the other.

Back  -    New Search

liothyronine (ly-oh-th'y-r-neen) n.

a hormone produced by the thyroid gland that is similar to thyroxine and is administered by mouth or injection to treat conditions of thyroid deficiency. Trade name: Tertroxin .

Back  -    New Search

lip- (lipo-) prefix

denoting 1 fat.

2 lipid.
Top

Back  -    New Search

lipaemia (lip-ee-mi) n.

the presence in the blood of an abnormally large amount of fat, such as cholesterol.

Back  -    New Search

lipase (steapsin) (lip-ayz) n.

an enzyme, produced by the pancreas and the glands of the small intestine, that breaks down fats into glycerol and fatty acids during digestion.

Back  -    New Search

lipid (lip-id) n.

one of a group of naturally occurring compounds that are soluble in solvents such as chloroform or alcohol, but insoluble in water. Lipids are important dietary constituents. The group includes fats, steroids, phospholipids, and glycolipids.

Back  -    New Search

lipidosis (lipoidosis) (lip-i-doh-sis) n. (pl. -ses)

any disorder of lipid metabolism within the cells of the body.

Back  -    New Search

Lipiodol (lip-l--dol) n.

Trademark. a preparation of iodine and poppy-seed oil, used as a contrast medium in X-ray examination of the bronchi, sinuses, and other cavities.

Back  -    New Search

lipochondrodystrophy (lip-oh-kon-droh-dis-tr-fi) n.

multiple congenital defects affecting lipid (fat) metabolism, cartilage and bone, skin, and the major internal organs, leading to mental retardation, dwarfism, and deformities of the bones.

Back  -    New Search

lipodystrophy (lip-oh-dis-tr-fi) n.

any disturbance of fat metabolism or of the distribution of fat in the body.

Back  -    New Search

lipogenesis (lip-oh-jen-i-sis) n.

the process by which glucose and other substances, derived from carbohydrate in the diet, are converted to fatty acids in the body.

Back  -    New Search

lipoid (lip-oid) n.

a substance, such as cholesterol, that resembles a lipid. l. factor one of the substances involved in the clotting of blood, important for the activation of plasma thromboplastin.

Back  -    New Search

lipoidosis (lip-oi-doh-sis) n.

see LIPIDOSIS.

Back  -    New Search

lipolysis (lip-ol-i-sis) n.

the process by which lipids are broken down into their constituent fatty acids in the body by the enzyme lipase.
—lipolytic adj.

Back  -    New Search

lipoma (lip-oh-m) n. (pl. lipomas or lipomata)

a common benign tumour that is composed of well-differentiated fat cells.

Back  -    New Search

lipomatosis (lip-oh-m-toh-sis) n.

1 the presence of an abnormally large amount of fat in the tissues.

2 the presence of multiple lipomas.
Top

Back  -    New Search

lipoprotein (lip-oh-proh-teen) n.

one of a group of proteins, found in blood plasma and lymph, that are combined with fats or other lipids (such as cholesterol). Lipoproteins are important for the transport of lipids in the blood and lymph. high-density l. (HDL) a type of lipoprotein with a relatively low concentration of cholesterol. low-density l. (LDL) a type of lipoprotein that is the main form in which cholesterol is transported in the bloodstream. very low-density l. (VLDL) a type of lipoprotein involved in the transport of cholesterol.

Back  -    New Search

liposarcoma (lip-oh-sar-koh-m) n.

a rare malignant tumour of fat cells. It is most commonly found in the thigh, usually in patients over the age of 30 years.

Back  -    New Search

lipotropic (lip-oh-trop-ik) adj.

describing a substance that promotes the transport of fatty acids from the liver to the tissues or accelerates the utilization of fat in the liver itself.

Back  -    New Search

lipping (lip-ing) n.

overgrowth of bone as seen in X-rays near a joint margin. This is a characteristic sign of degenerative or inflammatory joint disease, particularly osteoarthritis. See also OSTEOPHYTE.

Back  -    New Search

lipuria (adiposuria) (lip-yoor-i) n.

the presence of fat or oil droplets in the urine.

Back  -    New Search

liquor (lik-er) n.

(in pharmacy) any solution, usually an aqueous solution.

Back  -    New Search

lith- (litho-) prefix

denoting a calculus (stone).

Back  -    New Search

-lith suffix

denoting a calculus (stone).

Back  -    New Search

lithaemia (lith-ee-mi) n.

see HYPERURICAEMIA.

Back  -    New Search

lithiasis (lith-l--sis) n.

formation of stones (see CALCULUS) in an internal organ.

Back  -    New Search

lithium (lithium carbonate) (lith-im) n.

a drug given by mouth to prevent episodes of manic-depressive psychosis or to treat mania. Trade names: Camcolit , Litarex , Priadel .

Back  -    New Search

litholapaxy (lithotripsy) (lith-ol--paks-i) n.

the operation of crushing a stone in the bladder, using an instrument called a lithotrite . The small fragments of stone can then be removed by irrigation and suction.

Back  -    New Search

lithonephrotomy (lith-oh-ni-frot-mi) n.

surgical removal of a stone from the kidney. See NEPHROLITHOTOMY, PYELOLITHOTOMY.

Back  -    New Search

lithopaedion (lith-oh-pee-di-n) n.

a fetus that has died in the uterus or abdominal cavity and has become calcified.

Back  -    New Search

lithotomy (lith-ot-mi) n.

the surgical removal of a stone (calculus) from the urinary tract. See NEPHROLITHOTOMY, PYELOLITHOTOMY, URETEROLITHOTOMY.

Back  -    New Search

lithotripsy (lith--trip-si) n.

1 the destruction of calculi (stones) by means of shock waves. extracorporeal shock-wave l. (ESWL) a technique for destroying calculi in the upper urinary tract and gallstones; it uses a specialized machine (a lithotripter ) for generating and transmitting the shock waves and localizing the stones. electrohydraulic l. (EHL) a technique for destroying urinary calculi in which an electrically generated shock wave is transmitted to the stone by a contact probe delivered via a nephroscope.

2 see LITHOLAPAXY.
Top

Back  -    New Search

lithotripter (lith-oh-trip-ter) n.

see LITHOTRIPSY.

Back  -    New Search

lithotrite (lith--tryt) n.

see LITHOLAPAXY.

Back  -    New Search

lithuresis (lith-yoor-ee-sis) n.

the passage of small stones or gravel in the urine.

Back  -    New Search

lithuria (lith-yoor-i) n.

see HYPERURICURIA.

Back  -    New Search

litmus (lit-ms) n.

a pigment used as an indicator of acids and alkalis. In the presence of acids it turns red; with alkalis it turns blue.

Back  -    New Search

litre (lee-ter) n.

a unit of volume equal to the volume occupied by 1 kilogram of pure water at 4°C and 760 mmHg pressure.

Back  -    New Search

Little's area (li-t'lz) n.

the anterior region of the nasal septum (see NOSE), which is richly supplied with capillaries; it is a common site from which nosebleeds arise. [J. L. Little (1836–85), US surgeon]

Back  -    New Search

Little's disease n.

a form of cerebral palsy involving both sides of the body and affecting the legs more severely than the arms. [W. J. Little (1810–94), British surgeon]

Back  -    New Search

Litzmann's obliquity (lits-manz) n.

see ASYNCLITISM. [K. C. T. Litzmann (1815–90), German obstetrician]

Back  -    New Search

livedo (liv-ee-doh) n.

a discoloured area or spot on the skin, often caused by local congestion of the circulation.

Back  -    New Search

liver (liv-er) n.

the largest gland of the body, weighing 1200–1600 g. Situated in the top right portion of the abdominal cavity, the liver has a number of important functions. It synthesizes bile, which drains into the gall bladder before being released into the duodenum. The liver is an important site of metabolism of carbohydrates, proteins, and fats. It regulates the amount of blood sugar, removes excess amino acids, and stores and metabolizes fats. The liver also synthesizes fibrinogen, prothrombin, and heparin, and has an important role in the detoxification of poisonous substances.

Back  -    New Search

livid (liv-id) adj.

denoting a bluish colour of the skin, such as that produced locally by a bruise or of the general complexion in cyanosis.

Back  -    New Search

living will (liv-ing) n.

a statement signed by a person that outlines the degree of life-saving treatment desired in case of incapacitation. It enables terminally ill patients to refuse resuscitation in the event of cardiac arrest.

Back  -    New Search

Loa (loh-) n.

a genus of parasitic nematode worms (see FILARIA). L. loa the eye worm, which lives within the tissues beneath the skin and causes loiasis.

Back  -    New Search

lobe (lohb) n.

a major division of an organ or part of an organ, especially one having a rounded form and often separated from other lobes by fissures or bands of connective tissue.
—lobar adj.

Back  -    New Search

lobectomy (loh-bek-tmi) n.

the surgical removal of a lobe of an organ or gland, such as the lung, thyroid, or brain.

Back  -    New Search

lobotomy (prefrontal leucotomy) (loh-bot-mi) n.

see LEUCOTOMY.

Back  -    New Search

lobule (lob-yool) n.

a subdivision of a part or organ, such as the liver or lung, that can be distinguished from the whole by boundaries, such as septa, that are visible with or without a microscope.

Back  -    New Search

localized (loh-k-lyzd) adj.

(of a lesion, eruption, etc.) restricted to a particular part of the body; not widespread.

Back  -    New Search

lochia (lok-i) n.

the material eliminated from the uterus through the vagina after the completion of labour. The first discharge consists largely of blood (l. rubra ). This is followed by a brownish mixture of blood and mucus (l. serosa ), and finally a yellowish or whitish discharge containing microorganisms and cell fragments (l. alba ). Each stage may last for several days.
—lochial adj.

Back  -    New Search

locked-in syndrome (lokt-in) n.

a condition resulting from damage to the brainstem, in which the patient is conscious but unable to speak or to move any part of the body, except for blinking and upward eye movements, which permit signalling. Compare PERSISTENT VEGETATIVE STATE.

Back  -    New Search

lockjaw (lok-jaw) n.

see TETANUS.

Back  -    New Search

locomotor ataxia (loh-k-moh-ter) n.

see TABES DORSALIS.

Back  -    New Search

loculated (lok-yoo-layt-id) adj.

divided into many cavities.

Back  -    New Search

loculus (lok-yoo-ls) n.

(in anatomy) a small space or cavity.

Back  -    New Search

locum tenens (locum) (loh-km teen-enz) n.

a doctor who stands in temporarily for a colleague who is absent or ill.

Back  -    New Search

locus (loh-ks) n.

1 (in anatomy) a region or site.

2 (in genetics) the region of a chromosome occupied by a particular gene.
Top

Back  -    New Search

lofepramine (loh-fep-r-meen) n.

a tricyclic antidepressant administered by mouth or by injection. Trade name: Gamanil .

Back  -    New Search

log- (logo-) prefix

denoting words; speech.

Back  -    New Search

logopaedics (log--pee-diks) n.

the scientific study of defects and disabilities of speech and of the methods used to treat them; speech therapy.

Back  -    New Search

-logy (-ology) suffix

denoting field of study.

Back  -    New Search

loiasis (loh-l--sis) n.

a disease, occurring in West and Central Africa, caused by the eye worm Loa loa. The adult worms live and migrate within the skin tissues, causing inflammation and swellings, and often migrate across the eyeball just beneath the conjunctiva, producing irritation and congestion. Loiasis is treated with diethylcarbamazine.

Back  -    New Search

loin (loin) n.

the region of the back and side of the body between the lowest rib and the pelvis.

Back  -    New Search

Lomotil (lom--til) n.

see DIPHENOXYLATE.

Back  -    New Search

long-sightedness (long-syt-id-nis) n.

see HYPERMETROPIA.

Back  -    New Search

loop (loop) n.

1 a bend in a tubular organ.

2 one of the patterns of dermal ridges in fingerprints.
Top

Back  -    New Search

loperamide (loh-per--myd) n.

a drug used in the treatment of diarrhoea. It acts by reducing peristalsis of the digestive tract and is administered by mouth. Trade name: Imodium .

Back  -    New Search

loprazolam (loh-praz--lam) n.

a longacting benzodiazepine drug that is administered by mouth.

Back  -    New Search

lorazepam (lor-az--pam) n.

a benzodiazepine administered by mouth to relieve moderate or severe anxiety and tension and to treat insomnia. Trade name: Ativan .

Back  -    New Search

lordosis (lor-doh-sis) n.

inward curvature of the spine. A certain degree of lordosis is normal in the lumbar and cervical regions of the spine. Exaggerated lordosis may occur in adolescence, through faulty posture or as a result of disease. Compare KYPHOSIS.

Back  -    New Search

lotion (loh-shn) n.

a medicinal solution for external use. Lotions usually have a cooling, soothing, or antiseptic action.

Back  -    New Search

Lou Gehrig's disease (loo ge-rigz) n.

see (AMYOTROPHIC LATERAL) SCLEROSIS. [Lou Gehrig (1903–41), US baseball player who suffered from it]

Back  -    New Search

loupe (loop) n.

a small magnifying hand lens used for examining the front part of the eye.

Back  -    New Search

louse (lowss) n. (pl. lice)

a small wingless bloodsucking insect that is an external parasite of man and may transmit disease. Lice attach themselves to hair and clothing; they thrive in overcrowded and unhygienic conditions. See also PEDICULOSIS.

Back  -    New Search

lovastatin (loh-vas-t-tin) n.

a drug that interferes with the synthesis of cholesterol in the liver and is used to reduce abnormally high blood cholesterol levels.

Back  -    New Search

Løvset's manoeuvre (luv-setz) n.

rotation and traction of the trunk of the fetus during a breech birth to facilitate delivery of the arms and the shoulders. [J. Løvset (20th century), Norwegian obstetrician]

Back  -    New Search

low-density lipoprotein (LDL) (loh-den-siti) n.

see LIPOPROTEIN.

Back  -    New Search

low-molecular-weight heparin (loh-m-lek-yoo-ler-wayt) n.

see HEPARIN.

Back  -    New Search

lozenge (loz-inj) n.

a medicated tablet containing sugar.

Back  -    New Search

LSD n.

see LYSERGIC ACID DIETHYLAMIDE.

Back  -    New Search

lubb-dupp (lub-dup) n.

a representation of the normal heart sounds as heard through the stethoscope. The first coincides with closure of the mitral and tricuspid valves; the second with closure of the aortic and pulmonary valves.

Back  -    New Search

lucid interval (loo-sid in-ter-vl) n.

temporary recovery of consciousness after a blow to the head, before relapse into coma. It is a sign of intracranial arterial bleeding.

Back  -    New Search

Ludwig's angina (luud-vigz) n.

severe inflammation caused by bacterial infection of the floor of the mouth, resulting in massive swelling of the neck. [W. F. von Ludwig (1790–1865), German surgeon]

Back  -    New Search

lues (loo-eez) n.

a serious infectious disease such as syphilis.

Back  -    New Search

Lugol's solution (loo-golz) n.

an aqueous solution of iodine and potassium iodide. [J. G. A. Lugol (1786–1851), French physician]

Back  -    New Search

lumbago (lum-bay-goh) n.

low backache, of any cause or description. Severe lumbago, of sudden onset, can be due either to a slipped disc or to a strained muscle or ligament.

Back  -    New Search

lumbar (lum-ber) adj.

relating to the loin. l. puncture a procedure in which cerebrospinal fluid is withdrawn for diagnostic purposes by means of a hollow needle inserted into the subarachnoid space in the region of the lower back (usually between the third and fourth lumbar vertebrae). See also QUECKENSTEDT TEST. l. triangle a weak area in the abdomen bounded by the iliac crest (below), the external oblique muscle (in front), and the erector spinae muscle (behind). l. vertebrae the five bones of the backbone that are situated between the thoracic vertebrae and the sacrum, in the lower part of the back. See also VERTEBRA.

Back  -    New Search

lumbo- prefix

denoting the loin; lumbar region.

Back  -    New Search

lumbosacral (lum-boh-say-krl) adj.

relating to the part of the spine composed of the lumbar vertebrae and the sacrum.

Back  -    New Search

lumen (loo-min) n.

1 the space within a tubular or saclike part.

2 the SI unit of luminous flux. Symbol: lm.
Top

Back  -    New Search

luminescence (loo-min-ess-ns) n.

the emission of light from a substance after it has been irradiated. Fluorescence is a type of luminescence.

Back  -    New Search

lumpectomy (lum-pek-tmi) n.

an operation for breast cancer in which the tumour and surrounding breast tissue are removed: muscles, skin, and lymph nodes are left intact (compare MASTECTOMY). The procedure, usually followed by radiation, is indicated for patients with a tumour less than 2 cm in diameter and who have no metastases to local lymph nodes or to distant organs.

Back  -    New Search

lunate bone (loo-nayt) n.

a bone of the wrist (see CARPUS). It articulates with the capitate and hamate bones in front, with the radius behind, and with the triquetral and scaphoid at the sides.

Back  -    New Search

lung (lung) n.

one of the pair of organs of respiration, situated in the chest cavity on either side of the heart. The lungs communicate with the atmosphere through the trachea, which opens into the pharynx. The trachea divides into two bronchi, which enter the lungs and branch into bronchioles. These divide further and terminate in minute air sacs (alveoli: see illustration), the sites of gaseous exchange. Atmospheric oxygen is absorbed and carbon dioxide from the blood of the pulmonary capillaries is released into the lungs (see (PULMONARY) CIRCULATION).

Back  -    New Search

lung cancer n.

cancer arising in the epithelium of the air passages (bronchial cancer ) or lung. It is strongly associated with cigarette smoking and exposure to industrial air pollutants (including asbestos). Treatment includes surgical removal of the affected lobe or lung, radiotherapy, and chemotherapy.

Back  -    New Search

lunula (loon-yoo-l) n.

the whitish crescent-shaped area at the base of a nail.

Back  -    New Search

lupus (loo-ps) n.

any of several chronic skin diseases. l. erythematosus (LE) an inflammatory autoimmune disease of connective tissue. In systemic LE (SLE) the skin and various internal organs are affected. Typically, there is a red scaly rash on the nose and cheeks; arthritis; and progressive damage to the kidneys. Often the heart, lungs, and brain are also affected. In a milder form, known as discoid LE (DLE), only the skin is affected. LE is regarded as an autoimmune disease and is treated with corticosteroids or immunosuppressive drugs. l. verrucosus a rare tuberculous infection of the skin – commonly the arm or hand – typified by warty lesions. It occurs in those who have been reinfected with tuberculosis. l. vulgaris a tuberculous infection of the skin that often starts in childhood, with dark red patches on the nose or cheek. Unless treated with antituberculous drugs lupus vulgaris spreads, ulcerates, and causes extensive scarring.

Back  -    New Search

lutein (loo-ti-in) n.

1 see XANTHOPHYLL.

2 the yellow pigment of the corpus luteum.
Top

Back  -    New Search

luteinizing hormone (LH) (loo-ti-i-nyz-ing) n.

a hormone (see GONADOTROPHIN), synthesized and released by the anterior pituitary gland, that stimulates ovulation, corpus luteum formation, progesterone synthesis by the ovary, and androgen synthesis by the testes. Also called: interstitial-cell-stimulating hormone (ICSH).

Back  -    New Search

luteo- prefix

denoting 1 yellow.

2 the corpus luteum.
Top

Back  -    New Search

luteotrophic hormone (luteotrophin) (loo-ti-oh-trof-ik) n.

see PROLACTIN.

Back  -    New Search

luxation (luks-ay-shn) n.

see DISLOCATION.

Back  -    New Search

Lyell's disease (ly-lz) n.

see STAPHYLOCOCCAL SCALDED SKIN SYNDROME. [A. Lyell (20th century), British dermatologist]

Back  -    New Search

Lyme disease (lym) n.

a disease caused by a spirochaete, Borrelia burghdorferi, and transmitted by certain ticks of the genus Ixodes . Following a 3–32-day incubation period, a slowly extending red rash develops in approximately 75% of cases; intermittent symptoms include fever, malaise, headache and neck stiffness, and muscle and joint pains. Later, 60% of patients suffer intermittent attacks of arthritis, especially of the knees, each attack lasting months and recurring over several years. Treatment is with tetracycline or penicillin.

Back  -    New Search

lymph (limf) n.

the fluid present within the vessels of the lymphatic system, which is derived from the fluid that bathes the tissues. Lymph is similar in composition to plasma, but contains less protein and some cells, mainly lymphocytes. l. node one of a number of small swellings found at intervals along the lymphatic system. Groups of nodes occur in the groin and armpit, behind the ear, and in many other parts. They act as filters for the lymph and produce lymphocytes.

Back  -    New Search

lymphaden- (lymphadeno-) prefix

denoting lymph node(s).

Back  -    New Search

lymphadenectomy (lim-fad-in-ek-tmi) n.

surgical removal of lymph nodes.

Back  -    New Search

lymphadenitis (lim-fad-in-l-tis) n.

inflammation of lymph nodes, which become swollen, painful, and tender. The most commonly affected lymph nodes are those in the neck, in association with tonsillitis.

Back  -    New Search

lymphadenoma (lim-fad-in-oh-m) n.

an obsolete term for lymphoma.

Back  -    New Search

lymphangi- (lymphangio-) prefix

denoting a lymphatic vessel.

Back  -    New Search

lymphangiectasis (lim-fan-ji-ek-t-sis) n.

dilatation of the lymphatic vessels, which is usually congenital. It may also be caused by obstruction of the lymphatic vessels (see LYMPHOEDEMA).

Back  -    New Search

lymphangiography (lymphography) (lim-fan-ji-og-rfi) n.

X-ray examination of the lymphatic vessels and lymph nodes after a contrast medium has been injected into them (see ANGIOGRAPHY). Alternatively, the lymphatic system can be imaged using a gamma camera following the injection of a radioactive tracer.

Back  -    New Search

lymphangioma (lim-fan-ji-oh-m) n.

a localized collection of distended lymphatic vessels, which may result in a large cyst in the neck or armpit (cystic hygroma).

Back  -    New Search

lymphangioplasty (lim-fan-ji-oh-plasti) n.

the surgical creation of artificial lymph channels when the lymphatic vessels are obstructed.

Back  -    New Search

lymphangiosarcoma (lim-fan-ji-oh-sar-koh-m) n.

a rare malignant tumour of the lymphatic vessels. It is most commonly seen in the arms of women who have had a mastectomy for breast cancer.

Back  -    New Search

lymphangitis (lim-fan-jy-tis) n.

inflammation of the lymphatic vessels, which can be seen most commonly as red streaks in the skin adjacent to a focus of streptococcal infection.

Back  -    New Search

lymphatic (lim-fat-ik)

1 n. a lymphatic vessel. See LYMPHATIC SYSTEM.

2 adj. relating to or transporting lymph.
Top

Back  -    New Search

lymphatic system n.

a network of vessels that conveys electrolytes, water, proteins, etc. – in the form of lymph – from the tissue fluids to the bloodstream. Lymph passes through fine capillaries into the lymphatic vessels, which have valves to prevent backflow of lymph. The lymphatics lead to two large channels – the thoracic duct and the right lymphatic duct – which return the lymph to the bloodstream via the innominate veins.

Back  -    New Search

lympho- prefix

denoting lymph or the lymphatic system.

Back  -    New Search

lymphoblast (lim-foh-blast) n.

an abnormal cell that is present in the blood and blood-forming organs in a type of leukaemia (lymphoblastic leukaemia ).
—lymphoblastic adj.

Back  -    New Search

lymphocele (lim-foh-seel) n.

a collection of lymph in the tissues, which follows injury to, or operations upon, lymph nodes or ducts.

Back  -    New Search

lymphocyte (lim-foh-syt) n.

a variety of white blood cell (leucocyte), present also in the lymph nodes, spleen, thymus gland, gut wall, and bone marrow. They are involved in immunity and can be subdivided into B-lymphocytes (or B-cells ), which produce circulating antibodies, and T-lymphocytes , which are primarily responsible for cell-mediated immunity (see T-CELL).
—lymphocytic adj.

Back  -    New Search

lymphocytopenia (lim-foh-sy-toh-pee-ni) n.

see LYMPHOPENIA.

Back  -    New Search

lymphocytosis (lim-foh-sy-toh-sis) n.

an increase in the number of lymphocytes in the blood.

Back  -    New Search

lymphoedema (lim-fee-dee-m) n.

an accumulation of lymph in the tissues, producing swelling; the legs are most often affected. It may be due to a congenital abnormality of the lymphatic vessels (as in Milroy's disease) or result from obstruction of the lymphatic vessels by a tumour, parasites, inflammation, or injury.

Back  -    New Search

lymphogranuloma venereum (lim-foh-gran-yoo-loo-m vi-neer-im) n.

a sexually transmitted disease that is caused by bacteria of the genus Chlamydia and is most common in tropical regions. An initial lesion on the genitals is followed by swelling and inflammation of the lymph nodes in the groin. Early treatment with sulphonamides or tetracyclines is usually effective.

Back  -    New Search

lymphography (lim-fog-rfi) n.

see LYMPHANGIOGRAPHY.

Back  -    New Search

lymphoid tissue (lim-foid) n.

a tissue responsible for the production of lymphocytes and antibodies. It occurs in the form of the lymph nodes, tonsils, thymus, and spleen, and also as diffuse groups of cells. See also IMMUNE (SYSTEM).

Back  -    New Search

lymphokine (lim-foh-kyn) n.

a substance produced by lymphocytes that has effects on other cells involved in the immune system. An example is interleukin 2 (IL-2).

Back  -    New Search

lymphoma (lim-foh-m) n.

a malignant tumour of the lymph nodes, including Hodgkin's disease and other forms (non-Hodgkin's l. ). Disease may be widespread, but in some cases is confined to a single area, such as the tonsil. Treatment is with such drugs as chlorambucil or with combinations of cyclophosphamide, vincristine, and prednisone. See also BURKITT'S LYMPHOMA.

Back  -    New Search

lymphopenia (lymphocytopenia) (lim-foh-pee-ni) n.

a decrease in the number of lymphocytes in the blood.

Back  -    New Search

lymphopoiesis (lim-foh-poi-ee-sis) n.

the process of the production of lymphocytes, which occurs in the bone marrow as well as in the lymph nodes, spleen, thymus gland, and gut wall.

Back  -    New Search

lymphorrhagia (lim-f-ray-ji) n.

the escape of the lymph from lymphatic vessels that have been injured.

Back  -    New Search

lymphosarcoma (lim-foh-sar-koh-m) n.

an old term for non-Hodgkin's lymphoma.

Back  -    New Search

lymphuria (limf-yoor-i) n.

the presence in the urine of lymph.

Back  -    New Search

lyophilization (ly-ofi-ly-zay-shn) n.

preservation of biological material (e.g. plasma, serum, skin) by rapid freezing followed by dehydration.

Back  -    New Search

lys- (lysi-, lyso-) prefix

denoting lysis; dissolution.

Back  -    New Search

lysergic acid diethylamide (LSD) (ly-ser-jik ass-id dy-eth-il-ay-myd) n.

a psychedelic drug that is also a hallucinogen. It has been used to aid treatment of psychological disorders. Alterations in sight, hearing, and other senses occur, psychotic effects, depression, and confusion are common, and tolerance to the drug develops rapidly. Because of these toxic effects, LSD is no longer used clinically.

Back  -    New Search

lysin (ly-sin) n.

a protein component in the blood that is capable of bringing about the destruction (lysis) of whole cells. Haemolysin attacks red blood cells, leucolysin white cells, and a bacteriolysin bacterial cells.

Back  -    New Search

lysine (ly-seen) n.

an essential amino acid. See also AMINO ACID.

Back  -    New Search

lysis (ly-sis) n.

1 the destruction of cells through damage or rupture of the plasma membrane, allowing escape of the cell contents. See also AUTOLYSIS, LYSOZYME.

2 gradual remission of the symptoms of a disease.
Top

Back  -    New Search

-lysis suffix

denoting lysis; dissolution.

Back  -    New Search

lysosome (ly-s-sohm) n.

a particle in the cytoplasm of cells that contains enzymes responsible for breaking down substances in the cell. Lysosomes are especially abundant in liver and kidney cells.

Back  -    New Search

lysozyme (ly-s-zym) n.

an enzyme found in tears and egg white. It catalyses the destruction of the cell walls of certain bacteria.

Back  -    New Search

M

maceration (mas-er-ay-shn) n.

1 the softening of a solid by leaving it immersed in a liquid.

2 (in obstetrics) the natural breakdown of a dead fetus within the uterus.
Top

Back  -    New Search

Mackenrodt's ligaments (mahk-n-rohts) pl. n.

see CARDINAL LIGAMENTS. [A. K. Mackenrodt (1859–1925), German gynaecologist]

Back  -    New Search

macr- (macro-) prefix

denoting large size.

Back  -    New Search

macrocephaly (megalocephaly) (mak-roh-sef-li) n.

abnormal largeness of the head. Compare MICROCEPHALY.

Back  -    New Search

macrocheilia (mak-roh-ky-li) n.

hypertrophy of the lips: a congenital condition in which the lips are abnormally large. Compare MICROCHEILIA.

Back  -    New Search

macrocyte (megalocyte) (mak-roh-syt) n.

an abnormally large red blood cell (erythrocyte). See also MACROCYTOSIS.
—macrocytic adj.

Back  -    New Search

macrocytosis (mak-roh-sy-toh-sis) n.

the presence of macrocytes in the blood. Marocytosis is a feature of certain anaemias (known as macrocytic anaemias ), including those due to deficiency of vitamin B_12 or folic acid.

Back  -    New Search

macrodactyly (mak-roh-dak-tili) n.

abnormally large size of one or more of the fingers or toes.

Back  -    New Search

macrogenitosoma (mak-roh-jen-it-oh-soh-m) n.

excessive bodily growth with marked enlargement of the genitalia.

Back  -    New Search

macroglobulin (mak-roh-glob-yoo-lin) n.

1 (immunoglobulin M, IgM) a protein of the globulin series that is present in the blood and functions as an antibody, forming an effective first-line defence against any bacteria that enter the bloodstream. See also IMMUNOGLOBULIN.

2 an abnormal form of IgM.
Top

Back  -    New Search

macroglossia (mak-roh-glos-i) n.

an abnormally large tongue. It may be due to a congenital defect, to infiltration of the tongue with amyloid or a tumour, or to obstruction of the lymph vessels.

Back  -    New Search

macrognathia (mak-roh-nay-thi) n.

a condition in which one or both jaws are unusually large.

Back  -    New Search

macromelia (mak-roh-mee-li) n.

abnormally large size of the arms or legs. Compare MICROMELIA.

Back  -    New Search

macrophage (mak-roh-fayj) n.

a large scavenger cell (see PHAGOCYTE) present in connective tissue and many major organs and tissues, including the bone marrow, spleen, lymph nodes, liver, and the central nervous system. See also HISTIOCYTE, RETICULOENDOTHELIAL SYSTEM.

Back  -    New Search

macropsia (mak-rop-si) n.

a condition in which objects appear larger than they really are. It is usually due to disease of the retina.

Back  -    New Search

macroscopic (mak-roh-skop-ik) adj.

visible to the naked eye. Compare MICROSCOPIC.

Back  -    New Search

macrosomia (mak-roh-soh-mi) n.

abnormally large size. fetal m. large size in a baby associated with poorly controlled maternal diabetes; it is due to excessive production of fetal insulin and thence to increased deposition of glycogen in the fetus.

Back  -    New Search

macula (mak-yoo-l) n. (pl. maculae)

a small anatomical area that is distinguishable from the surrounding tissue. m. lutea the yellow spot on the retina at the back of the eye, which surrounds the greatest concentration of cones (see FOVEA).
—macular adj.

Back  -    New Search

macular degeneration (mak-yoo-ler) n.

a group of conditions affecting the macula lutea of the eye, resulting in a reduction or loss of central vision. age-related m. d. (AMD, ARMD) the most common cause of blindness in the elderly. Atrophic or dry AMD results from chronic choroidal ischaemia: small blood vessels of the choroid, which lies beneath the retina, become constricted, reducing the blood supply to the macula. This gives rise to degenerative changes in the retinal pigment epithelium (RPE; see RETINA). Wet AMD is associated with the growth of abnormal new blood vessels under the retina, derived from the choroid (see (CHOROIDAL) NEOVASCULARIZATION). These can leak fluid and blood into the RPE, which further reduces macular function.

Back  -    New Search

macule (mak-yool) n.

a flat circumscribed area of skin or an area of altered skin colour (e.g. a freckle). Compare PAPULE.
—macular adj.

Back  -    New Search

maculopapular (mak-yoo-loh-pap-yoo-ler) adj.

describing a rash that consists of both macules and papules.

Back  -    New Search

maculopathy (mak-yool-op--thi) n.

any abnormality of the macula lutea of the eye. bull's-eye m. the appearance of the macula in some toxic conditions (e.g. chloroquine toxicity) and in some hereditary disorders of the macula.

Back  -    New Search

Madopar (mad-oh-par) n.

see BENSERAZIDE.

Back  -    New Search

Madura foot (m-dewr-) n.

an infection of the tissues and bones of the foot producing chronic inflammation (mycetoma), occurring in the tropics. Medical name: maduromycosis .

Back  -    New Search

Madurella (mad-yoo-rel-) n.

a genus of widely distributed fungi. The species M. grisea and M. mycetomi cause the tropical infection Madura foot.

Back  -    New Search

maduromycosis (m-dewr-oh-my-koh-sis) n.

see MADURA FOOT.

Back  -    New Search

Magendie's foramen (ma-jen-deez) n.

an opening in the roof of the fourth ventricle of the brain through which cerebrospinal fluid passes to the subarachnoid space. [F. Magendie (1783–1855), French physiologist]

Back  -    New Search

magenta (m-jen-t) n.

see FUCHSIN.

Back  -    New Search

maggot (mag-t) n.

the wormlike larva of a fly, which occasionally infests human tissues (see MYIASIS).

Back  -    New Search

magnesium (mag-nee-zim) n.

a metallic element essential to life. Magnesium is necessary for the proper functioning of muscle and nervous tissue. Symbol: Mg. m. carbonate a weak antacid used to relieve indigestion and also pain due to stomach and duodenal ulcers; it is also used as a mild laxative. m. hydroxide a magnesium salt with effects and uses similar to those of magnesium carbonate. Trade name: Milk of Magnesia . m. sulphate a magnesium salt given in mixtures or enemas to treat constipation (see LAXATIVE). It is also administered by injection to treat magnesium deficiency. m. trisilicate a compound of magnesium with antacid and absorbent properties, used in the treatment of peptic ulcers and other digestive disorders.

Back  -    New Search

magnetic resonance imaging (MRI) (mag-net-ik) n.

a diagnostic technique based on analysis of the absorption and transmission of high-frequency radio waves by the water molecules in tissues placed in a strong magnetic field (see NUCLEAR MAGNETIC RESONANCE). Using modern high-speed computers, this analysis can be used to produce images of the tissues in any plane of the body. It is particularly useful for examining the central nervous system and musculoskeletal system and enables the noninvasive diagnosis and treatment planning of a wide range of diseases. The magnetic resonance therapy scanner enables interventional procedures to be performed very accurately under MRI control. MRI does not use potentially harmful ionizing radiation, such as X-rays.

Back  -    New Search

MAGPI operation (mag-py) n.

meatal advancement and glanuloplasty operation: a simple surgical procedure that is designed to correct minor to moderate degrees of coronal or subcoronal hypospadias. This single-stage operation corrects any associated minor degrees of chordee and transfers the urethral opening to the glans.

Back  -    New Search

MAI complex n.

a group of bacteria comprising Mycobacterium avium and M. intracellulare, which are responsible for opportunistic infections of the lung that mimic tuberculosis but are resistant to many antituberculosis drugs. These bacteria are particularly liable to cause superimposed infection in AIDS patients. See MYCOBACTERIUM.

Back  -    New Search

mal (mal) n.

illness or disease.

Back  -    New Search

mal- prefix

denoting disease, disorder, or abnormality.

Back  -    New Search

malabsorption (mal-b-sorp-shn) n.

a state in which absorption by the small intestine of one or more substances, such as fat, vitamins, or amino acids, is reduced. Symptoms (depending on the substances involved) include weight loss, diarrhoea, anaemia, swelling (oedema), and vitamin deficiencies. The commonest causes are coeliac disease, pancreatitis, cystic fibrosis, blind-loop syndrome, or surgical removal of a length of small intestine.

Back  -    New Search

malacia (m-lay-shi) n.

abnormal softening of a part, organ, or tissue, such as bone (see OSTEOMALACIA).

Back  -    New Search

-malacia suffix

denoting abnormal softening of a tissue.

Back  -    New Search

maladie de Roger (Roger's disease) (ma-la-di d ro-zhay) n.

a form of congenital heart disease in which there is a small ventricular septal defect. It usually causes no symptoms. [H. L. Roger (1809–91), French physician]

Back  -    New Search

malaise (mal-ayz) n.

a general feeling of being unwell. The feeling may be accompanied by identifiable physical discomfort and may indicate the presence of disease.

Back  -    New Search

malar bone (may-ler) n.

see ZYGOMATIC BONE.

Back  -    New Search

malaria (ague, marsh fever, periodic fever, paludism) (m-lair-i) n.

an infectious disease due to the presence of parasitic protozoa of the genus Plasmodium within the red blood cells. The disease is transmitted by the Anopheles mosquito and is confined mainly to tropical and subtropical areas. After an incubation period varying from 12 days to 10 months parasites invade, multiply within, and eventually destroy the red blood cells, releasing new parasites. This causes a short bout of shivering, fever, and sweating, and the loss of healthy red cells results in anaemia. When the next batch of parasites is released symptoms reappear. The interval between fever attacks varies in different types of malaria (see QUARTAN FEVER, QUOTIDIAN FEVER, TERTIAN FEVER). Preventive and curative treatment relies on such drugs as chloroquine and proguanil. A vaccine is being tested.

Back  -    New Search

malarial therapy (m-lair-il) n.

a treatment for neurosyphilis in which a high fever is induced by infecting the patient with malaria parasites.

Back  -    New Search

malathion (mal--th'y-on) n.

an organophosphorous insecticide used to treat head and pubic lice and scabies. It is applied externally in the form of a lotion. Trade names: Derbac-M , Prioderm , Soleo-M .

Back  -    New Search

malformation (mal-for-may-shn) n.

any variation from the normal physical structure, due either to congenital or developmental defects or to disease or injury.

Back  -    New Search

malignant (m-lig-nnt) adj.

1 describing a tumour that invades and destroys the tissue in which it originates and can spread to other sites in the body. If untreated such tumours cause progressive deterioration and death. See CANCER.

2 describing any disorder that becomes life threatening if untreated. Compare BENIGN.
Top

Back  -    New Search

malignant melanoma (MM) n.

see MELANOMA.

Back  -    New Search

malignant pustule n.

see ANTHRAX.

Back  -    New Search

malingering (m-ling-er-ing) n.

pretending to be ill, usually in order to avoid work or to gain attention. It may be a sign of mental disorder (see MUNCHAUSEN'S SYNDROME).

Back  -    New Search

malleolus (m-lee--ls) n.

either of the two protuberances on each side of the ankle: at the lower end of the fibula (lateral m. ) and at the lower end of the tibia (medial m. ).

Back  -    New Search

mallet finger (mal-it fing-er) n.

a condition in which a finger (usually the index finger) is bent downwards at the tip, due to avulsion of the long extensor tendon from the bone.

Back  -    New Search

malleus (mal-is) n.

a hammer-shaped bone in the middle ear that articulates with the incus and is attached to the eardrum. See OSSICLE.

Back  -    New Search

Mallory bodies (mal-eri) pl. n.

large irregular masses located in the hepatocytes of the liver. They are found in patients with alcoholic hepatitis, Wilson's disease, primary biliary cirrhosis, severe obesity, and hepatocellular carcinoma. [F. B. Mallory (1862–1941), US pathologist]

Back  -    New Search

Mallory-Weiss syndrome (mal-eri-vys) n.

tearing of the tissues around the junction of the oesophagus (gullet) and stomach as a result of violent vomiting or straining to vomit. It is associated with haematemesis and perforation of the oesophagus. [G. K. Mallory (1926– ), US pathologist; S. Weiss (1899–1942), US physician]

Back  -    New Search

malnutrition (mal-new-trish-n) n.

the condition caused by an improper balance between what an individual eats and what he requires to maintain health. This can result from eating too little (subnutrition or starvation ) but may also imply dietary excess or an incorrect balance of basic foodstuffs.

Back  -    New Search

malocclusion (mal--kloo-zhn) n.

a condition in which there is an abnormal arrangement of the teeth, either within one jaw or in one jaw in relation to the other.

Back  -    New Search

Malpighian body (mal-pig-in) n.

the part of a nephron comprising the blood capillaries of the glomerulus and its surrounding Bowman's capsule. [M. Malpighi (1628–94), Italian anatomist]

Back  -    New Search

Malpighian layer n.

the stratum germinativum: one of the layers of the epidermis.

Back  -    New Search

malposition (mal-p-zish-n) n.

(in obstetrics) an abnormal position of the fetal head when this is the presenting part in labour, such that the diameter of the skull in relation to the pelvic opening is greater than normal. This is likely to result in a prolonged and complicated labour.

Back  -    New Search

malpractice (mal-prak-tis) n.

professional misconduct: treatment falling short of the standards of skill and care that can reasonably be expected from a qualified medical practitioner.

Back  -    New Search

malpresentation (mal-prez-n-tay-shn) n.

the condition in which the presenting part of the fetus (see PRESENTATION) is other than the head.

Back  -    New Search

malt (mawlt) n.

a mixture of carbohydrates, predominantly maltose, produced by the breakdown of starch contained in barley or wheat grains. Malt is used for brewing and distilling; it has been used as a source of nutrients in wasting diseases.

Back  -    New Search

Malta fever (mawl-t) n.

see BRUCELLOSIS.

Back  -    New Search

maltase (mawl-tayz) n.

an enzyme, present in saliva and pancreatic juice, that converts maltose into glucose during digestion.

Back  -    New Search

maltose (mawl-tohz) n.

a sugar consisting of two molecules of glucose. Maltose is formed from the digestion of starch and glycogen.

Back  -    New Search

malunion (mal-yoon-yn) n.

deformity of a bone resulting from union of a fracture in which the bone ends are poorly aligned. Osteotomy may be needed to correct the deformity.

Back  -    New Search

mamilla (m-mil-) n.

see NIPPLE.

Back  -    New Search

mamma (mam-) n.

see BREAST.

Back  -    New Search

mammary gland (mam-er-i) n.

the milk producing gland of female mammals. See BREAST.

Back  -    New Search

mammography (mam-og-rfi) n.

X-ray examination of the female breast: used particularly to enable the early diagnosis of breast cancer. See also FORREST SCREENING.

Back  -    New Search

mammoplasty (mam--plasti) n.

plastic surgery of the breasts, in order to alter their shape or increase or decrease their size.

Back  -    New Search

mammothermography (mam-oh-ther-mog-rfi) n.

the technique of examining the breasts for the presence of abnormalities by thermography.

Back  -    New Search

M-AMSA (amsacrine) n.

a cytotoxic drug undergoing evaluation in the treatment of malignant disease.

Back  -    New Search

Manchester operation (man-ches-ter) n.

see DONALD-FOTHERGILL OPERATION.

Back  -    New Search

mandible (man-dib-l) n.

the lower jawbone. It consists of a horseshoe-shaped body, the upper surface of which bears the lower teeth, and two vertical parts (rami). See also TEMPOROMANDIBULAR JOINT.
—mandibular (man-dib-yoo-ler) adj.

Back  -    New Search

manganese (mang--neez) n.

a greyish metallic element, the oxide of which, when inhaled by miners in underventilated mines, causes brain damage. It is a trace element. Symbol: Mn.

Back  -    New Search

mania (may-ni) n.

a state of mind characterized by excessive cheerfulness and increased activity. The mood is euphoric and changes rapidly to irritability. Thought and speech are rapid to the point of incoherence and the connections between ideas may be impossible to follow.
Treatment is usually with drugs such as lithium or phenothiazines. See AFFECTIVE DISORDER, MANIC-DEPRESSIVE PSYCHOSIS.
—manic (man-ik) adj.

Back  -    New Search

-mania suffix

denoting obsession, compulsion, or exaggerated feeling for.

Back  -    New Search

manic-depressive psychosis (bipolar disorder) (man-ik-di-pres-iv) n.

a severe mental illness that causes repeated episodes of depression, mania, or both. Treatment is with phenothiazine drugs for mania and with antidepressant drugs or electroconvulsive therapy for depression. Lithium and carbamazepine can prevent or reduce the frequency and severity of attacks, and the sufferer is usually well in the intervals between them.

Back  -    New Search

manipulation (m-nip-yoo-lay-shn) n.

the use of the hands to produce a desired movement or therapeutic effect in part of the body.

Back  -    New Search

mannitol (man-i-tol) n.

a diuretic administered by injection to supplement other diuretics in the treatment of fluid retention (oedema), to treat some kidney disorders, and to relieve pressure in brain injuries.

Back  -    New Search

manometer (m-nom-it-er) n.

a device for measuring pressure in a liquid or gas. See also SPHYGMOMANOMETER.

Back  -    New Search

manometry (m-nom-itri) n.

measurement of pressures within organs of the body. The technique is used to record changes within fluid-filled chambers (e.g. cerebral ventricles) or to indicate muscular activity in motile tubes, such as the oesophagus, rectum, or bile duct.

Back  -    New Search

mantle (man-t'l) adj.

(in radiotherapy) see FIELD.

Back  -    New Search

Mantoux test (man-too) n.

a test for immunity to tuberculosis. Tuberculin is injected beneath the skin and a patch of inflammation appearing in the next 48–72 hours indicates that a degree of immunity is present. [C. Mantoux (1877–1947), French physician]

Back  -    New Search

manubrium (m-new-bri-m) n. (pl. manubria)

1 the upper section of the breastbone (see STERNUM). It articulates with the clavicles and the first costal cartilage.

2 the handle-like part of the malleus, attached to the eardrum.
Top

—manubrial adj.

Back  -    New Search

MAO n.

see MONOAMINE OXIDASE.

Back  -    New Search

MAO inhibitor n.

any drug, such as phenelzine, that prevents the activity of the enzyme monoamine oxidase (MAO) in brain tissue and therefore affects mood. MAO inhibitors are antidepressants; their side-effects include interactions with other drugs and foods containing tyramine (e.g. cheese) to produce a sudden increase in blood pressure. See also MOCLOBEMIDE, SELEGILINE.

Back  -    New Search

maple syrup urine disease (may-pl si-rp) n.

an inborn defect of amino acid metabolism causing an excess of valine, leucine, isoleucine, and alloisoleucine in the urine, which has an odour like maple syrup. Treatment is dietary; if untreated, the condition leads to mental retardation and death in infancy.

Back  -    New Search

maprotiline (m-proh-til-een) n.

a drug administered by mouth to treat all types of depression, including that associated with anxiety (see ANTIDEPRESSANT). It is administered by mouth and may cause drowsiness, dizziness, and tremor. Trade name: Ludiomil .

Back  -    New Search

marasmus (m-raz-ms) n.

severe wasting in infants, when body weight is below 75% of that expected for age. The infant looks ‘old’, pallid, apathetic, lacks skin fat, and has subnormal temperature. The condition may be due to malabsorption, wrong feeding, metabolic disorders, repeated vomiting, diarrhoea, or disease.

Back  -    New Search

marble-bone disease (mar-bl bohn) n.

see OSTEOPETROSIS.

Back  -    New Search

Marburg disease (green monkey disease) (mar-berg) n.

a virus disease of vervet (green) monkeys transmitted to man by contact with blood or tissues from an infected animal. Symptoms include fever, malaise, severe headache, vomiting, diarrhoea, and bleeding from mucous membranes. Treatment with antiserum and measures to reduce the bleeding are sometimes effective.

Back  -    New Search

Marcus Gunn jaw-winking syndrome (mar-ks gun) n.

a congenital condition characterized by drooping (ptosis) of one eyelid. On opening or moving the mouth, the droopy lid elevates momentarily, resembling a wink. [R. Marcus Gunn (1850–1909), British ophthalmologist]

Back  -    New Search

Marfan's syndrome (mar-fahnz) n.

an inherited disorder of connective tissue characterized by excessive height, abnormally long and slender fingers and toes (arachnodactyly ), heart defects, and partial dislocation of the lenses of the eyes. [B. J. A. Marfan (1858–1942), French physician]

Back  -    New Search

marijuana (ma-ri-hwah-n) n.

see CANNABIS.

Back  -    New Search

Marion's disease (ma-ri-nz) n.

obstruction of the outlet of the bladder caused by enlargement of the muscle cells in the neck of the bladder. [J. B. C. G. Marion (1869–1960), French surgeon]

Back  -    New Search

Marjolin's ulcer (mar-zhoh-lanz) n.

a carcinoma that develops at the edge of a chronic ulcer of the skin, usually a venous ulcer in the ankle region. [J. N. Marjolin (1780–1850), French surgeon]

Back  -    New Search

marrow (ma-roh) n.

see BONE MARROW.

Back  -    New Search

marsupialization (mar-soo-pil-l-zay-shn) n.

an operative technique for curing a cyst. The cyst is opened, its contents removed, and the edges then stitched to the skin incision.

Back  -    New Search

masculinization (mas-kew-lin-l-zay-shn) n.

development of excess body and facial hair, deepening of the voice, and increase in muscle bulk in a female due to a hormone disorder or to hormone therapy. See also VIRILISM, VIRILIZATION.

Back  -    New Search

Maslow's hierarchy of human needs (maz-lohz) n.

a listing of human needs in order of priority, from basic physiological needs (e.g. eating and drinking) to self-actualization. It is held that the individual does not consider meeting each level of need until the previous level has been at least partly satisfied. See SELF-ACTUALIZATION. [A. H. Maslow (1908–70), US psychologist]

Back  -    New Search

masochism (mas--kizm) n.

sexual pleasure derived from the experience of pain. See SEXUAL DEVIATION.
—masochist n.—masochistic adj.

Back  -    New Search

massage (mas-ahzh) n.

manipulation of the soft tissues of the body with the hands. Massage is used to improve circulation, prevent adhesions in tissues after injury, and reduce muscular spasm. See also EFFLEURAGE, PETRISSAGE, TAPOTEMENT.

Back  -    New Search

masseter (ma-see-ter) n.

a thick muscle in the cheek extending from the zygomatic arch to the outer corner of the mandible. It is important for mastication and acts by closing the jaws.

Back  -    New Search

mast-(masto-) prefix

denoting the breast.

Back  -    New Search

mastalgia (mas-tal-ji) n.

pain in the breast.

Back  -    New Search

mastatrophy (mastatrophia) (mas-tat-rfi) n.

atrophy of the breasts.

Back  -    New Search

mast cell (mahst) n.

a large cell in connective tissue. Mast cells contain heparin, histamine, and serotonin, which are released during inflammation and allergic responses.

Back  -    New Search

mastectomy (mas-tek-tmi) n.

surgical removal of a breast. radical m. surgical removal of the breast with the skin and all the lymphatic tissue of the armpit. In modern surgical practice the underlying pectoral muscles are usually preserved. It is performed when breast cancer has spread to involve the lymph nodes. simple m. surgical removal of the breast retaining the skin and, if possible, the nipple. It is performed for extensive but not necessarily invasive tumours. See also LUMPECTOMY.

Back  -    New Search

mastication (mas-ti-kay-shn) n.

the process of chewing food.

Back  -    New Search

mastitis (mas-ty-tis) n.

inflammation of the breast, usually caused by bacterial infection via damaged nipples. ystic m. chronic mastitis in which the breast feels lumpy due to the presence of cysts. puerperal m. acute mastitis that develops during the period of breast-feeding.

Back  -    New Search

mastoid (mas-toid) adj.

relating to the mastoid process. m. antrum an air-filled channel connecting the mastoid process to the cavity of the middle ear. m. cells air spaces in the mastoid process. m. process a nipple-shaped process on the temporal bone that extends downward and forward behind the ear canal.

Back  -    New Search

mastoidectomy (mas-toi-dek-tmi) n.

an operation to remove some or all of the mastoid cells when they have become infected (see MASTOIDITIS) or invaded by cholesteatoma.

Back  -    New Search

mastoiditis (mas-toi-dy-tis) n.

inflammation of the mastoid process and antrum, usually caused by bacterial infection that spreads from the middle ear. See OTITIS (MEDIA).

Back  -    New Search

masturbation (mas-ter-bay-shn) n.

physical self-stimulation of the male or female external genital organs in order to produce sexual pleasure, which may result in orgasm.

Back  -    New Search

materia medica (m-teer-i med-ik-) n.

the study of drugs used in medicine and dentistry, including pharmacognosy, pharmacy, pharmacology, and therapeutics.

Back  -    New Search

maternal deprivation (m-ter-nl) n.

the condition said to result if infants are deprived of the opportunity to form a close relationship with a single parental figure, who may or may not be the child's natural parent. It is characterized by distress and depression, leading to an inability to form lasting relationships.

Back  -    New Search

maternal mortality rate n.

the number of deaths due to complications of pregnancy, childbirth, and the puerperium expressed as a proportion of all births (i.e. including stillbirths). The rate is usually expressed per 100,000 births.

Back  -    New Search

matrix (may-triks) n.

the substance of a tissue or organ in which more specialized structures are embedded.

Back  -    New Search

mattress suture (mat-ris) n.

a suture in which a loop is made on each side of the incision, which may be parallel with the incision (horizontal m. s. ) or at right angles to it (vertical m. s. ).

Back  -    New Search

maturation (mat-yoor-ay-shn) n.

the process of attaining full development.

Back  -    New Search

maxilla (maks-il-) n. (pl. maxillae)

1 (loosely) the upper jaw.

2 either of the pair of bones contributing to the upper jaw, the orbits, the nasal cavity, and the roof of the mouth (see PALATE).
Top

—maxillary (maks-il-er-i) adj.

Back  -    New Search

maxillary sinus (maxillary antrum) n.

see PARANASAL SINUSES.

Back  -    New Search

maxillofacial (maks-il-oh-fay-shl) adj.

describing or relating to the region of the face, jaws, and related structures.

Back  -    New Search

mazindol (m-zin-dol) n.

a drug that reduces the appetite and is administered by mouth in the treatment of obesity. Trade name: Teronac .

Back  -    New Search

McArdle's disease (mk-ar-d'lz) n.

an inborn error of metabolism in which a deficiency of the enzyme myophosphorylase prevents the breakdown of glycogen to lactate in exercising muscle. This results in fatigue, pain, and cramps in exercising muscles. [B. McArdle (20th century), British biochemist]

Back  -    New Search

McBurney's point (mk-ber-niz) n.

the point on the abdomen that overlies the anatomical position of the appendix and is the site of maximum tenderness in acute appendicitis. [C. McBurney (1845–1913), US surgeon]

Back  -    New Search

MCU n.

see MICTURATING CYSTOURETHROGRAM.

Back  -    New Search

ME n.

myalgic encephalomyelitis. See CHRONIC FATIGUE SYNDROME.

Back  -    New Search

mean (arithmetic mean) (meen) n.

the average of a group of observations calculated by adding their values and dividing by the number in the group.

Back  -    New Search

measles (mee-zlz) n.

a highly infectious virus disease that mainly affects children. Early symptoms are those of a cold accompanied by a high fever, and Koplik's spots may appear on the inside of the cheeks. On the third to fifth day a blotchy slightly elevated pink rash develops; it lasts 3–5 days. The patient is infectious throughout this period. In most cases the symptoms soon subside but patients are susceptible to pneumonia and middle ear infections. Medical names: rubeola , morbilli .

Back  -    New Search

meat- (meato-) prefix

denoting a meatus.

Back  -    New Search

meatus (mee-ay-ts) n.

(in anatomy) a passage or opening. external auditory m. the auditory canal: the passage leading from the pinna of the outer ear to the eardrum. nasal m. one of three groovelike parts of the nasal cavity beneath each of the nasal conchae. urethral m. the external opening of the urethra.

Back  -    New Search

mebendazole (mi-ben-d-zohl) n.

an anthelmintic drug used to get rid of roundworms, hookworms, pinworms, and whipworms. Trade name: Vermox . See also IMIDAZOLE.

Back  -    New Search

mebhydrolin (meb-hy-droh-lin) n.

an antihistamine drug used to treat allergic conditions, such as hay fever and urticaria. Trade name: Fabahistin .

Back  -    New Search

mechanism of labour (mek--nizm) n.

the sum of the forces that act to expel a fetus from the uterus together with those that resist its expulsion and affect its position during birth. See LABOUR.

Back  -    New Search

mechanotherapy (mek--noh-th'e-r-pi) n.

the use of mechanical equipment during physiotherapy to produce regularly repeated movements in part of the body.

Back  -    New Search

Meckel's diverticulum (mek-lz) n.

see DIVERTICULUM. [J. F. Meckel (1781–1833), German anatomist]

Back  -    New Search

meclozine (mek-l-zeen) n.

an antihistamine drug administered by mouth to prevent and treat nausea and vomiting, particularly in motion sickness, and also to relieve allergic reactions.

Back  -    New Search

meconism (mek-oh-nizm) n.

poisoning from the effects of eating or smoking opium or the products derived from it, especially morphine.

Back  -    New Search

meconium (mi-koh-nim) n.

the first stools of a newborn baby, which are sticky and dark green and composed of cellular debris, mucus, and bile pigments. m. ileus obstruction of the ileum caused by thickened meconium in babies with cystic fibrosis.

Back  -    New Search

media (tunica media) (meed-i) n.

1 the middle layer of the wall of a vein or artery.

2 the middle layer of various other organs or parts.
Top

Back  -    New Search

medial (mee-di-l) adj.

relating to or situated in the central region of an organ, tissue, or the body.

Back  -    New Search

median (mee-di-n) adj.

(in anatomy) situated in or towards the plane that divides the body into right and left halves.

Back  -    New Search

mediastinitis (mee-di-asti-ny-tis) n.

inflammation of the mediastinum, usually complicating a rupture of the oesophagus (gullet).

Back  -    New Search

mediastinoscopy (mee-di-asti-nos-kpi) n.

examination of the mediastinum, usually by means of an endoscope inserted through a small incision in the neck region. It can be used to assess the spread of intrathoracic tumours and for lymph node biopsy.

Back  -    New Search

mediastinum (mee-di--sty-nm) n.

the space in the thorax between the two pleural sacs. The mediastinum contains the heart, aorta, trachea, oesophagus, and thymus gland.

Back  -    New Search

medical (med-ik-l) adj.

1 of or relating to the science or practice of medicine.

2 of or relating to conditions that require the attention of a physician rather than a surgeon.
Top

Back  -    New Search

medical assistant n.

a health service worker who is not a registered medical practitioner (often a nurse or an exserviceman with experience as a senior medical orderly) working in association with a doctor to undertake minor treatments and preliminary assessments.

Back  -    New Search

medical certificate n.

a certificate stating a doctor's diagnosis of a patient's medical condition, disability, or fitness to work.

Back  -    New Search

medical jurisprudence n.

the study or practice of the legal aspects of medicine. See FORENSIC MEDICINE.

Back  -    New Search

medical social worker n.

a social worker employed to assist patients with domestic problems that may arise through illness.

Back  -    New Search

medicated (med-i-kayt-id) adj.

containing a medicinal drug: applied to lotions, soaps, sweets, etc.

Back  -    New Search

medication (med-i-kay-shn) n.

1 a substance administered by mouth, applied to the body, or introduced into the body for the purpose of treatment. See also PREMEDICATION.

2 treatment of a patient using drugs.
Top

Back  -    New Search

medicine (med-sin) n.

1 the science or practice of the diagnosis, treatment, and prevention of disease.

2 the science or practice of nonsurgical methods of treating disease.
Top

3 any drug or preparation used for the treatment or prevention of disease, particularly a preparation that is taken by mouth.
Top

Back  -    New Search

medicochirurgical (med-i-koh-ky-rer-jik-l) adj.

of or describing matters that are related to both medicine and surgery.

Back  -    New Search

medicolegal (med-i-koh-lee-gl) adj.

relating to the legal aspects of the practice of medicine.

Back  -    New Search

Mediterranean fever (med-it-er-ay-ni-n) n.

1 see BRUCELLOSIS.

2 see POLYSEROSITIS.
Top

Back  -    New Search

medium (meed-im) n.

1 any substance, usually a broth, agar, or gelatin, used for the culture of microorganisms or tissue cells.

2 see CONTRAST MEDIUM.
Top

Back  -    New Search

medroxyprogesterone (med-roks-i-proh-jes-ter-ohn) n.

a synthetic female sex hormone (see PROGESTOGEN) used to treat menstrual disorders, to prevent miscarriage, and in oral contraceptives. It is administered by mouth or injection. Trade names: Farlutal , Provera .

Back  -    New Search

medulla (mi-dul-) n.

1 the inner region of any organ or tissue, particularly the inner part of the kidney, adrenal glands, or lymph nodes. m. oblongata (myelencephalon) the extension within the skull of the upper end of the spinal cord, containing centres responsible for the regulation of the heart and blood vessels, respiration, salivation, and swallowing.

2 the myelin layer of certain nerve fibres.
Top

—medullary adj.

Back  -    New Search

medullated (myelinated) nerve fibre (med-l-ayt-id) n.

see MYELIN.

Back  -    New Search

medulloblastoma (mi-dul-oh-blas-toh-m) n.

a malignant brain tumour that occurs during childhood and develops in the cerebellum. Symptoms include headaches, dizziness, and unsteadiness; the flow of cerebrospinal fluid may become obstructed, causing hydrocephalus. Treatment involves surgery followed by radiotherapy.

Back  -    New Search

mefenamic acid (me-fen-am-ik) n.

an anti-inflammatory drug (see NSAID) administered by mouth to treat headache, toothache, rheumatic pain, and similar conditions. Trade name: Ponstan .

Back  -    New Search

mefloquine (mef-loh-kween) n.

a drug used in the prevention and treatment of malaria that is resistant to other drugs. It is administered by mouth but should not be taken during pregnancy, by psychiatric patients, or with beta blockers. Trade name: Lariam .

Back  -    New Search

mefruside (mef-roo-syd) n.

a thiazide-like diuretic used to treat high blood pressure and get rid of excess body fluid. It is administered by mouth. Trade name: Baycaron .

Back  -    New Search

mega- prefix

denoting 1 large size or abnormal enlargement or distension.

2 a million.
Top

Back  -    New Search

megacolon (meg--koh-ln) n.

dilatation, and sometimes lengthening, of the colon. It is caused by obstruction of the colon, Hirschsprung's disease, or longstanding constipation.

Back  -    New Search

megakaryocyte (meg--ka-ri-oh-syt) n.

a cell in the bone marrow that produces platelets. See also THROMBOPOIESIS.

Back  -    New Search

megal- (megalo-) prefix

denoting abnormal enlargement.

Back  -    New Search

megaloblast (meg--loh-blast) n.

an abnormal form of erythroblast. Megaloblasts are unusually large and their nuclei fail to mature in the normal way; they are seen in the bone marrow in certain anaemias (megaloblastic anaemias ) due to deficiency of vitamin B_12 or folic acid.
—megaloblastic adj.

Back  -    New Search

megalocephaly (meg--loh-sef-li) n.

1 see MACROCEPHALY.

2 overgrowth and distortion of the skull bones (see LEONTIASIS).
Top

Back  -    New Search

megalocyte (meg--loh-syt) n.

see MACROCYTE.

Back  -    New Search

megalomania (meg--loh-may-ni) n.

delusions of grandeur. It may be a feature of a schizophrenic or manic illness or of cerebral syphilis.

Back  -    New Search

-megaly suffix

denoting abnormal enlargement.

Back  -    New Search

megaureter (meg--yoor-ee-ter) n.

gross dilatation of the ureter. This occurs above the site of a longstanding obstruction in the ureter, which blocks the free flow of urine from the kidney.

Back  -    New Search

megestrol (mi-jes-trohl) n.

a synthetic female sex hormone (see PROGESTOGEN) that is used in the treatment of metastatic breast cancer and metastatic endometrial cancer. Trade name: Megace .

Back  -    New Search

meibomian cyst (my-boh-mi-n) n.

see CHALAZION. [H. Meibom (1638–1700), German anatomist]

Back  -    New Search

meibomian glands (tarsal glands) pl. n.

small sebaceous glands that lie under the conjunctiva of the eyelids.

Back  -    New Search

meibomianitis (my-boh-mi-n-I-tis) n.

inflammation of the meibomian glands of the eyelids.

Back  -    New Search

Meigs' syndrome (megz) n.

the accumulation of fluid in the pleural and peritoneal cavities associated with a benign tumour of the ovary. [J. V. Meigs (1892–1963), US surgeon]

Back  -    New Search

meiosis (reduction division) (my-oh-sis) n.

a type of cell division that produces four daughter cells, each having half the number of chromosomes of the original cell. It occurs before the formation of sperm and ova and the normal (diploid) number of chromosomes is restored after fertilization. Compare MITOSIS.
—meiotic (my-ot-ik) adj.

Back  -    New Search

Meissner's plexus (submucous plexus) (my-snerz) n.

a fine network of parasympathetic nerve fibres in the wall of the alimentary canal, supplying the muscles and mucous membrane. [G. Meissner (1829–1905), German physiologist]

Back  -    New Search

melaena (mi-lee-n) n.

black tarry faeces due to the presence of partly digested blood from higher up the digestive tract. It often occurs after vomiting blood (see HAEMATEMESIS), having the same causes, but may be due to disease in the small intestine or upper colon, such as carcinoma or angiodysplasia. See also HAEMORRHAGIC DISEASE OF THE NEWBORN.

Back  -    New Search

melan- (melano-) prefix

denoting 1 black coloration.

2 melanin.
Top

Back  -    New Search

melancholia (mel-n-koh-li) n.

see DEPRESSION, INVOLUTIONAL MELANCHOLIA.

Back  -    New Search

melanin (mel-n-in) n.

a dark-brown to black pigment occurring in the hair, the skin, and in the iris and choroid layer of the eyes.

Back  -    New Search

melanism (melanosis) (mel-n-izm) n.

an unusually pronounced darkening of body tissues caused by excessive production of the pigment melanin. Melanism may affect the skin after sunburn, during pregnancy, or in Addison's disease.

Back  -    New Search

melanocyte (mel--noh-syt) n.

a cell within the epidermis of skin that produces melanin.

Back  -    New Search

melanocyte-stimulating hormone (MSH) n.

a hormone synthesized and released by the pituitary gland. In amphibians MSH brings about colour changes in the skin but its physiological role in man is uncertain.

Back  -    New Search

melanoma (malignant melanoma, MM) (mel--noh-m) n.

a highly malignant tumour of melanocytes. Such tumours usually occur in the skin (excessive exposure to sunlight is a contributory factor) but are also found in the eye and the mucous membranes. They may contain melanin or be free of the pigment (amelanotic m. ). Superficial melanomas can often be successfully treated by surgical excision.

Back  -    New Search

melanophore (mel--noh-for) n.

a cell that contains melanin.

Back  -    New Search

melanoplakia (mel--noh-play-ki) n.

pigmented areas of melanin in the mucous membrane lining the inside of the cheeks.

Back  -    New Search

melanosis (mel--noh-sis) n.

1 see MELANISM.

2 a disorder in the body's production of the pigment melanin.
Top

3 cachexia associated with the spread of the skin cancer melanoma.
Top

—melanotic adj.

Back  -    New Search

melanuria (mel-n-yoor-i) n.

the presence of dark pigment in the urine. This may occur in some cases of melanoma; it may alternatively be caused by metabolic disease, such as porphyria.

Back  -    New Search

melasma (mi-laz-m) n.

see CHLOASMA.

Back  -    New Search

melatonin (mel--toh-nin) n.

a hormone produced by the pineal gland in darkness but not in bright light. Melatonin is a derivative of serotonin, with which it works to regulate the sleep cycle.

Back  -    New Search

melioidosis (mee-li-oi-doh-sis) n.

a disease of wild rodents caused by the bacterium Pseudomonas pseudomallei. It can be transmitted to man, causing pneumonia, multiple abscesses, and septicaemia.

Back  -    New Search

melphalan (mel-f-lan) n.

a drug administered by mouth or injection to treat various types of cancer, including malignant melanoma, tumours of the breast and ovaries, and Hodgkin's disease. Trade name: Alkeran .

Back  -    New Search

membrane (mem-brayn) n.

1 a thin layer of tissue surrounding an organ or tissue, lining a cavity, or separating adjacent structures or cavities. See also BASEMENT MEMBRANE, MUCOUS MEMBRANE, SEROUS MEMBRANE.

2 the lipoprotein envelope surrounding a cell (cell m. ).
Top

—membranous (mem-brn-s) adj.

Back  -    New Search

membranous labyrinth n.

see LABYRINTH.

Back  -    New Search

MEN n.

multiple endocrine neoplasia. See MENS.

Back  -    New Search

men- (meno-) prefix

denoting menstruation.

Back  -    New Search

menarche (men-ar-ki) n.

the start of the menstrual periods and other physical and mental changes associated with puberty. The menarche occurs when the reproductive organs become functionally active and may take place at any time between 10 and 19 years of age.

Back  -    New Search

Mendel's laws (men-d'lz) pl. n.

rules of inheritance based on the breeding experiments of Gregor Mendel , which showed that the inheritance of characteristics is controlled by particles now known as genes. In modern terms they are as follows.
(1) Each somatic cell of an individual carries two factors (genes) for every characteristic and each gamete carries only one.
(2) Each pair of factors segregates independently of all other pairs at meiosis, so that the gametes show all possible combinations of factors. See also DOMINANT, RECESSIVE. [G. J. Mendel (1822–84), Austrian monk]

Back  -    New Search

Mendelson's syndrome (men-d'l-snz) n.

inhalation of regurgitated stomach contents by an anaesthetized patient, which may result in death from anoxia or cause extensive lung damage or pulmonary oedema with severe bronchospasm. It may be prevented by giving gastric-acid inhibitors (e.g. cimetidine, ranitidine) or sodium citrate before inducing anaesthesia. [C. L. Mendelson (1913– ), US obstetrician]

Back  -    New Search

Ménétrier's disease (may-nay-tri-ayz) n.

a disorder in which gross enlargement (see HYPERTROPHY) of the cells of the mucous membrane lining the stomach is associated with anaemia. [P. Ménétrier (1859–1935), French physician]

Back  -    New Search

menidrosis (menhidrosis) (men-id-roh-sis) n.

the production of sweat, sometimes containing blood, instead of the normal menstrual flow.

Back  -    New Search

Ménière's disease (mayn-yairz) n.

a disease of the inner ear characterized by episodes of deafness, buzzing in the ears (tinnitus), and vertigo. Symptoms last for several hours and between attacks the affected ear may return to normal. It is thought to be caused by the build-up of fluid in the inner ear and is treated by drugs or surgery. Medical name: endo-lymphatic hydrops. [P. Ménière (1799–1862), French physician]

Back  -    New Search

mening- (meningo-) prefix

denoting the meninges.

Back  -    New Search

meninges (min-in-jeez) pl. n. (sing. meninx)

the three connective tissue membranes that line the skull and vertebral canal and enclose the brain and spinal cord: the dura mater, arachnoid mater, and pia mater.
—meningeal adj.

Back  -    New Search

meningioma (min-in-ji-oh-m) n.

a tumour arising from the meninges. It is usually slow-growing and produces symptoms by pressure on the underlying nervous tissue. Some meningiomas (meningeal sarcomas ) are malignant and invade neighbouring tissues. Treatment of the majority of cases is by surgical removal if the tumour is accessible.

Back  -    New Search

meningism (men-in-jizm) n.

stiffness of the neck mimicking that found in meningitis. It is usually a symptom of chest infection or inflammation in the upper respiratory tract.

Back  -    New Search

meningitis (men-in-jy-tis) n.

an inflammation of the meninges due to viral or bacterial infection. Meningitis causes an intense headache, fever, loss of appetite, intolerance to light and sound, rigidity of muscles, especially those in the neck (see also KERNIG'S SIGN), and in severe cases convulsions, vomiting, and delirium leading to death. Bacterial meningitis can be effectively treated with large doses of antibiotics administered as soon as possible after diagnosis. See also HIB VACCINE. meningococcal m. (cerebrospinal fever , spotted fever ) a serious form of bacterial meningitis, caused by the meningococcus, that can lead to widespread infection and septicaemia.

Back  -    New Search

meningocele (min-ing-oh-seel) n.

protrusion of the meninges through a gap in the spine. See NEURAL TUBE DEFECTS.

Back  -    New Search

meningococcus (min-ing-oh-kok-s) n. (pl. meningococci)

the bacterium Neisseria meningitidis, which can cause a serious form of septicaemia and is a common cause of meningitis.
—meningococcal adj.

Back  -    New Search

meningoencephalitis (min-ing-oh-en-sef--ly-tis) n.

inflammation of the brain and the meninges caused by bacterial or viral infection.

Back  -    New Search

meningoencephalocele (min-ing-oh-en-sef--loh-seel) n.

protrusion of the meninges and brain through a defect in the skull. See NEURAL TUBE DEFECTS.

Back  -    New Search

meningomyelocele (myelocele, myelomeningocele) (min-ing-oh-my--loh-seel) n.

protrusion of the meninges, spinal cord, and nerve roots through a gap in the spine, accompanied by paralysis of the legs and urinary incontinence. See NEURAL TUBE DEFECTS.

Back  -    New Search

meningovascular (min-ing-oh-vas-kew-ler) adj.

relating to or affecting the meninges and the blood vessels that penetrate them to supply the underlying neural tissues.

Back  -    New Search

meniscectomy (men-i-sek-tmi) n.

surgical removal of a cartilage (meniscus) in the knee. This is carried out when the meniscus has been torn or is diseased. The operation can now be performed through an arthroscope.

Back  -    New Search

meniscus (min-isk-s) n.

(in anatomy) a crescent-shaped structure, such as the fibrocartilaginous disc that divides the cavity of a synovial joint.

Back  -    New Search

menopause (climacteric) (men--pawz) n.

the time in a woman's life when ovulation and menstruation cease and the woman is no longer able to bear children. The menopause can occur at any age between the middle thirties and the middle fifties, but occurs most commonly between 45 and 55; it can only be established in retrospect after 12 consecutive months of amenorrhoea. It is associated with a change in the balance of sex hormones in the body, which sometimes leads to hot flushes and other vasomotor symptoms, palpitations, and emotional disturbances.
—menopausal adj.

Back  -    New Search

menorrhagia (epimenorrhagia) (men--ray-ji) n.

abnormally heavy bleeding at menstruation. Menorrhagia may be associated with hormonal imbalance (in which case it is described as dysfunctional uterine bleeding ), pelvic inflammatory disease, tumours (especially fibroids) in the pelvic cavity, endometriosis, or the presence of an IUCD.

Back  -    New Search

MENS (menz) n.

multiple endocrine neoplasia syndromes: a group of syndromes characterized by combinations of symptoms and signs caused by tumours and/or hyperplasia of more than one endocrine gland (multiple endocrine neoplasia , MEN). The tumours may involve the pituitary, thyroid, parathyroid, and adrenal glands and the pancreas.

Back  -    New Search

menses (men-seez) n.

1 the blood and other materials discharged from the uterus at menstruation.

2 see MENSTRUATION.
Top

Back  -    New Search

menstrual cycle (men-stroo-l) n.

the periodic sequence of events in sexually mature nonpregnant women by which an egg cell (ovum) is released from a follicle in the ovary at four-weekly intervals until the menopause (see illustration). The secretion of progesterone in the ruptured follicle causes the lining of the uterus (endometrium) to become thicker and richly supplied with blood in preparation for pregnancy. If the ovum is not fertilized the endometrium is shed at menstruation.

Back  -    New Search

menstruation (menses) (men-stroo-ay-shn) n.

the discharge of blood and fragments of endometrium from the vagina at intervals of about four weeks in women of child-bearing age (see MENARCHE, MENOPAUSE). The normal duration of discharge varies from three to seven days. anovular m. discharge that takes place without previous release of an egg cell from the ovary. vicarious m. bleeding from a mucous membrane other than the endometrium when normal menstruation is due. See also AMENORRHOEA, DYSMENORRHOEA, EPIMENORRHOEA, HYPOMENORRHOEA, MENORRHAGIA, OLIGOMENORRHOEA.

Back  -    New Search

mental^1 (men-t'l) adj.

relating to or affecting the mind.

Back  -    New Search

mental^2 adj.

relating to the chin.

Back  -    New Search

mental age n.

a measure of the intellectual level at which an individual functions; for example, someone having a mental age of 6 years would be functioning at the level of an average 6-year-old child. See also INTELLIGENCE QUOTIENT.

Back  -    New Search

mental handicap n.

delayed or incomplete intellectual development combined with some form of social malfunction, such as educational or occupational failure or inability to look after oneself. Good education alters the course of the handicap, for which the term learning disability is often used.

Back  -    New Search

Mental Health Acts pl. n.

the Acts of Parliament governing the care of the mentally disordered. They provide for compulsory admission when the mentally disordered put themselves or other people into danger, protection of the civil rights of patients, and for the Mental Health Act Commission to regulate aspects of the practice of psychiatry.

Back  -    New Search

Mental Health Review Tribunal n.

one of a number of tribunals, established under the Mental Health Act 1959 and now operating under the Mental Health Act 1983, to which applications may be made for the discharge from hospital of a person compulsorily detained there under provisions of the Act (see COMPULSORY ADMISSION).

Back  -    New Search

mental illness n.

a disorder of one or more of the functions of the mind, which causes suffering to the patient or others. Mental illness is broadly divided into psychosis, in which the capacity for appreciating reality is lost, and neurosis, in which insight is retained.

Back  -    New Search

mental impairment n.

(mostly in legal usage) the condition of significant or severe impairment of intellectual and social functioning associated with abnormally aggressive or seriously irresponsible behaviour.

Back  -    New Search

mental retardation n.

the state of those whose intellectual powers have failed to develop to such an extent that they are in need of care and protection and require special education. There are very many causes of mental retardation, including Down's syndrome, fragile-X syndrome, inherited metabolic disorders, brain injury, and gross psychological deprivation; some are preventable or treatable. See also MENTAL HANDICAP.

Back  -    New Search

menthol (men-thol) n.

a compound extracted from peppermint oil, used in inhalants to relieve cold symptoms, in ointments and liniments, and to relieve itching. Formula:
C_10H_20O
.

Back  -    New Search

mento- prefix

denoting the chin.

Back  -    New Search

mentor (men-tor) n.

a person with the experience and knowledge to fulfil the role of a trusted friend and adviser. The mentor guides, counsels, and supports a student or junior in a clinical or educational area.

Back  -    New Search

mentum (men-tm) n.

the chin.

Back  -    New Search

mepacrine (mep--kreen) n.

a drug administered by mouth to treat various infestations, particularly giardiasis and taeniasis; it was formerly widely used to treat malaria but has now largely been replaced by safer drugs.

Back  -    New Search

meperidine (mi-pe-ri-deen) n.

see PETHIDINE.

Back  -    New Search

meprobamate (mi-proh-b-mayt) n.

a mild tranquillizer administered by mouth or injection to relieve anxiety and nervous tension. Trade name: Equanil .

Back  -    New Search

meralgia paraesthetica (mi-ral-ji-pa-ris-thet-ik-) n.

painful tingling and numbness felt over the outer surface of the thigh when the lateral cutaneous nerve is trapped as it passes through the muscular tissues of the groin.

Back  -    New Search

mercaptopurine (mer-kap-t-pewr-een) n.

a drug that prevents the growth of cancer cells and is administered by mouth, chiefly in the treatment of some types of leukaemia (see ANTIMETABOLITE). Trade name: Puri-Nethol .

Back  -    New Search

mercurialism (hydrargyria) (mer-kewr-i-lizm) n.

mercury poisoning. Acute poisoning causes vomiting, diarrhoea, and kidney damage. Treatment is with dimercaprol. Chronic poisoning causes mouth ulceration, loose teeth, and intestinal and renal disturbances. Treatment is removing the patient from further exposure.

Back  -    New Search

mercury (mer-kewr-i) n.

a silvery metallic element that is liquid at room temperature. Its toxicity has caused a decline in the use of its compounds in medicine. The main use of mercury today is as a component of amalgam fillings in dentistry. Symbol: Hg. See also MERCURIALISM, PINK DISEASE.

Back  -    New Search

mes- (meso-) prefix

denoting middle or medial.

Back  -    New Search

mesaortitis (mes-ay-or-ty-tis) n.

inflammation of the middle layer (media) of the wall of the aorta, generally the result of late syphilis.

Back  -    New Search

mesarteritis (mes-ar-ter-I-tis) n.

inflammation of the middle layer (media) of an artery, which is often combined with inflammation in all layers of the artery wall.

Back  -    New Search

mescaline (mesk--leen) n.

an alkaloid present in the dried tops of the cactus Lophophora williamsii that produces inebriation and hallucinations when ingested.

Back  -    New Search

mesencephalon (mes-en-sef--lon) n.

see MIDBRAIN.

Back  -    New Search

mesentery (mes-n-ter-i) n.

a double layer of peritoneum attaching the stomach, small intestine, pancreas, spleen, and other abdominal organs to the posterior wall of the abdomen.
—mesenteric (mes-n-te-rik) adj.

Back  -    New Search

mesial (mee-zi-l) adj.

1 medial.

2 relating to or situated in the median line or plane.
Top

3 designating the surface of a tooth towards the midline of the jaw.
Top

Back  -    New Search

mesmerism (mez-mer-izm) n.

hypnosis based on the ideas of Franz Mesmer, sometimes employing magnets and a variety of other equipment. [F. A. Mesmer (1734–1815), Austrian physician]

Back  -    New Search

mesna (mez-n) n.

a drug administered intravenously by injection or infusion to prevent the toxic effect of if osfamide and cyclophosphamide on the bladder. It binds with the toxic metabolite acrolein in the urine.

Back  -    New Search

mesoappendix (mes-oh--pen-diks) n.

the mesentery of the appendix.

Back  -    New Search

mesocolon (mes-oh-koh-lon) n.

the fold of peritoneum by which the colon is fixed to the posterior abdominal wall.

Back  -    New Search

mesoderm (mes-oh-derm) n.

the middle germ layer of the early embryo. It gives rise to cartilage, muscle, bone, blood, kidneys, gonads and their ducts, and connective tissue.
—mesodermal adj.

Back  -    New Search

mesometrium (mes-oh-mee-tri-m) n.

the broad ligament of the uterus: a sheet of connective tissue that carries blood vessels to the uterus and attaches it to the abdominal wall.

Back  -    New Search

mesomorphic (mes-oh-mor-fik) adj.

describing a body type characterized by a well developed skeletal and muscular structure and a sturdy upright posture.
—mesomorph n. —mesomorphy n.

Back  -    New Search

mesonephros (Wolffian body) (mes-oh-nef-ross) n.

kidney tissue that is functional only in the embryo. Its duct – the mesonephric (or Wolffian ) duct – persists in males as the epididymis and vas deferens.
—mesonephric adj.

Back  -    New Search

mesosalpinx (mes-oh-sal-pinks) n.

a fold of peritoneum that surrounds the Fallopian tubes. It is the upper part of the broad ligament that surrounds the uterus.

Back  -    New Search

mesotendon (mes-oh-ten-dn) n.

the delicate connective tissue membrane that surrounds a tendon.

Back  -    New Search

mesothelioma (mes-oh-th'ee-li-oh-m) n.

a tumour of the pleura, peritoneum, or pericardium. The occurrence of pleural mesothelioma is often due to exposure to asbestos dust (see ASBESTOSIS).

Back  -    New Search

mesothelium (mes-oh-th'ee-lim) n.

the single layer of cells that lines serous membranes. It is derived from embryonic mesoderm. Compare EPITHELIUM.

Back  -    New Search

mesovarium (mes-oh-vair-im) n.

the mesentery of the ovaries.

Back  -    New Search

messenger RNA (mes-in-jer) n.

a type of RNA that carries the information of the genetic code of the DNA from the cell nucleus to the ribosomes, where the code is translated into protein. See TRANSCRIPTION, TRANSLATION.

Back  -    New Search

mestranol (mes-tr-nol) n.

a synthetic female sex hormone (see OESTROGEN) that is used, in combination with a progestogen, to treat menopausal symptoms (see HORMONE REPLACEMENT THERAPY) and as a constituent of oral contraceptive pills. Trade names: Menophase , Norinyl-1 .

Back  -    New Search

met-(meta-) prefix

denoting 1 distal to; beyond; behind.

2 change; transformation.
Top

Back  -    New Search

metabolism (mi-tab-l-izm) n.

1 the sum of all the chemical and physical changes that take place within the body and enable its continued growth and functioning. Metabolism involves the breakdown of complex organic constituents of the body (see CATABOLISM) and the building up of complex substances from simple ones (see ANABOLISM). See also BASAL METABOLISM.

2 the sum of the biochemical changes undergone by a particular constituent of the body.
Top

—metabolic (met--bol-ik) adj.

Back  -    New Search

metabolite (mi-tab--lyt) n.

a substance that takes part in the process of metabolism.

Back  -    New Search

metacarpal (met--kar-pl)

1 adj. relating to the metacarpus.

2 n. any of the bones forming the metacarpus.
Top

Back  -    New Search

metacarpophalangeal (met--kar-poh-fal-n-jee-l) adj.

relating to the metacarpal bones and the phalanges, especially to the joints between these bones.

Back  -    New Search

metacarpus (met--kar-ps) n.

the five bones of the hand that connect the carpus (wrist) to the phalanges (digits).

Back  -    New Search

metamorphopsia (met--mor-fop-si) n.

a condition in which objects appear distorted. It is usually due to a disorder of the retina affecting the macula.

Back  -    New Search

metamorphosis (met--mor-f-sis) n.

a structural change, especially the change from one developmental stage to another that occurs in certain animals (e.g. in amphibians from larval to adult form).

Back  -    New Search

metaphase (met--fayz) n.

the second stage of mitosis and of each division of meiosis, in which the spindle forms and the chromosomes line up at the centre of the spindle, with their centromeres attached to the spindle fibres.

Back  -    New Search

metaphysis (mi-taf-i-sis) n.

the growing portion of a long bone that lies between the epiphyses and the diaphysis.

Back  -    New Search

metaplasia (met--play-zi) n.

an abnormal change in the nature of a tissue. myeloid m. the development of bone marrow elements in organs such as the spleen and liver. This may occur after bone marrow failure.

Back  -    New Search

metaraminol (met--ram-i-nol) n.

a sympathomimetic drug that stimulates alpha receptors and is used to treat severe anaphylactic shock (see ANAPHYLAXIS). It is administered by injection. Trade name: Aramine .

Back  -    New Search

metastasis (mi-tas-t-sis) n. (pl. metastases)

the distant spread of disease, especially a malignant tumour, from its site of origin. This occurs by three main routes:
(1)  through the bloodstream;
(2)  through the lymphatic system;
(3)  across body cavities.

—metastatic (met--stat-ik) adj.

Back  -    New Search

metastasize (mi-tas-t-syz) vb.

(of a malignant tumour) to spread by metastasis.

Back  -    New Search

metatarsal (met--tar-sl)

1 adj. relating to the metatarsus.

2 n. any of the bones forming the metatarsus.
Top

Back  -    New Search

metatarsalgia (met--tar-sal-ji) n.

aching pain in the metatarsal bones of the foot. Repeated injury, arthritis, and deformities of the foot are common causes, and corrective footwear and insoles may be prescribed.

Back  -    New Search

metatarsus (met--tar-ss) n.

the five bones of the foot that connect the tarsus (ankle) to the phalanges (toes).

Back  -    New Search

meteorism (meet-i-er-izm) n.

see TYMPANITES.

Back  -    New Search

-meter suffix

denoting an instrument for measuring.

Back  -    New Search

metformin (met-for-min) n.

a biguanide drug that reduces blood sugar levels and is administered by mouth to treat noninsulin-dependent diabetes. Trade name: Glucophage. See also ORAL HYPOGLYCAEMIC DRUG.

Back  -    New Search

methadone (meth--dohn) n.

a potent narcotic analgesic drug administered by mouth or injection to relieve severe pain, as a linctus to suppress coughs, and to treat heroin addiction. Trade name: Physeptone .

Back  -    New Search

methaemalbumin (met-heem-al-bew-min) n.

a chemical complex of the pigment portion of haemoglobin (haem) with the plasma protein albumin. It is formed in the blood in anaemias in which red blood cells are destroyed and free haemoglobin is released into the plasma.

Back  -    New Search

methaemoglobin (met-hee-m-gloh-bin) n.

a substance formed when the iron atoms of haemoglobin have been oxidized from the ferrous to the ferric form (compare OXYHAEMOGLOBIN). Methaemoglobin cannot bind molecular oxygen and therefore cannot transport oxygen round the body.

Back  -    New Search

methaemoglobinaemia (met-hee-m-gloh-bin-ee-mi) n.

the presence of methaemoglobin in the blood, which may result from ingestion of oxidizing drugs. Symptoms are fatigue, headache, dizziness and cyanosis.

Back  -    New Search

methanol (meth--nol) n.

see METHYL ALCOHOL.

Back  -    New Search

methenamine (meth-en--meen) n.

see HEXAMINE.

Back  -    New Search

methicillin (meth-i-sil-in) n.

a semisynthetic penicillin formerly used to treat infections caused by bacteria that destroy natural penicillin but now replaced by newer antibiotics. It is still used to test the drug sensitivity of staphylococci. m-resistant Staphylococcus aureus see MRSA.

Back  -    New Search

methionine (meth-I--neen) n.

a sulphur-containing essential amino acid. See also AMINO ACID.

Back  -    New Search

methixene (meth-iks-een) n.

a drug with effects similar to those of atropine, administered by mouth to control the tremors and other symptoms in parkinsonism and to relieve spasm of smooth muscle in digestive disorders. Trade name: Tremonil .

Back  -    New Search

methoserpidine (meth-oh-ser-pi-deen) n.

a drug that lowers the blood pressure. It is administered by mouth. Trade name: Decaserpyl .

Back  -    New Search

methotrexate (meth-oh-treks-ayt) n.

a drug that interferes with cell growth and is administered by mouth or injection to treat various types of cancer, including leukaemia (see ANTIMETABOLITE). Trade name: Maxtrex .

Back  -    New Search

methotrimeprazine (meth-oh-try-mep-r-zeen) n.

a tranquillizing, sedative, and analgesic drug administered by mouth or injection to treat anxiety, tension, and agitation and to relieve moderate or severe pain. Trade name: Nozinan .

Back  -    New Search

methoxamine (meth-oks--meen) n.

a sympathomimetic drug that causes blood vessels to be constricted and therefore raises blood pressure. It is administered by injection to maintain the blood pressure during surgical operations. Trade name: Vasoxine .

Back  -    New Search

methyclothiazide (meth-i-kloh-th'y--zyd) n.

a thiazide diuretic administered by mouth in the treatment of high blood pressure (hypertension) and oedema associated with congestive heart failure, cirrhosis, other drug therapy, and kidney dysfunction. It prevents reabsorption of sodium, chloride, and, to a lesser extent, potassium. Trade name: Enduron .

Back  -    New Search

methyl alcohol (methanol) (mee-thyl) n.

wood alcohol: an alcohol that is oxidized in the body much more slowly than ethyl alcohol and forms poisonous products. As little as 10 ml of pure methyl alcohol can produce permanent blindness, and 100 ml is likely to be fatal. See also METHYLATED SPIRITS.

Back  -    New Search

methylamphetamine (mee-thyl-am-fet-min) n.

a drug with actions and side-effects similar to those of amphetamine. It is administered by mouth to treat narcolepsy and parkinsonism and some depressive states. It is also administered by injection to restore the blood pressure in surgical procedures and to treat drug overdosage.

Back  -    New Search

methylated spirits (meth-il-ayt-id) n.

a mixture consisting mainly of ethyl alcohol with methyl alcohol and petroleum hydrocarbons. It is used as a solvent, cleaning fluid, and fuel.

Back  -    New Search

methylcellulose (mee-thyl-sel-yoo-lohz) n.

a compound that absorbs water and is administered by mouth as a bulk laxative to treat constipation, to control diarrhoea, and in patients with a colostomy. Trade name: Celevac .

Back  -    New Search

methyldopa (mee-thyl-doh-pa) n.

a drug that reduces blood pressure (see SYMPATHOLYTIC). It is administered by mouth or injection. Trade names: Aldomet , Dopamet , Hydromet , Medomet .

Back  -    New Search

methylphenidate (mee-thyl-fen-id-ayt) n.

a sympathomimetic drug that also stimulates the central nervous system. It is administered by mouth or injection to treat attention deficit disorder in children, to improve mental activity in convalescence and some depressive states, and to overcome lethargy associated with drug treatment. Trade name: Ritalin .

Back  -    New Search

methylprednisolone (mee-thyl-pred-nis--lohn) n.

a glucocorticoid that is used in the treatment of inflammatory conditions, such as rheumatoid arthritis, rheumatic fever, and allergic states, and for adrenocortical insufficiency. It is administered by mouth, intravenously, and intramuscularly. Trade names: Depo-Medrone , Medrone , Solu-Medrone .

Back  -    New Search

methyl salicylate n.

oil of wintergreen: a liquid with counterirritant and analgesic properties, applied to the skin to relieve pain in lumbago, sciatica, and rheumatic conditions.

Back  -    New Search

methyltestosterone (mee-thyl-test-ost-er-ohn) n.

a synthetic male sex hormone (see ANDROGEN) administered by mouth to treat sexual underdevelopment in men. It is also used to suppress lactation, to treat menstrual and menopausal disorders, and to treat breast cancer in women.

Back  -    New Search

methylthiouracil (mee-thyl-th'y-oh-yoor--sil) n.

a drug that inhibits thyroid activity, formerly administered by mouth to treat overactivity of the thyroid gland (see THYROTOXICOSIS). Carbimazole is now preferred.

Back  -    New Search

methysergide (meth-i-ser-jyd) n.

a drug administered by mouth to prevent severe migraine attacks and to control diarrhoea associated with tumours in the digestive system. Trade name: Deseril .

Back  -    New Search

metoclopramide (met-oh-kloh-pr-myd) n.

a drug that antagonizes the actions of dopamine. It is administered by mouth or injection to treat nausea, vomiting, indigestion, heartburn, and flatulence. Trade names: Gastromax , Maxolon , Primperan .

Back  -    New Search

metolazone (met-oh-l-zohn) n.

a diuretic administered by mouth to treat fluid retention (oedema) and high blood pressure. Trade names: Metenix , Xuret .

Back  -    New Search

metoprolol (met-oh-proh-lol) n.

a drug that controls the activity of the heart (see BETA BLOCKER) and is administered by mouth to treat high blood pressure and angina. Trade names: Betaloc , Lopresor .

Back  -    New Search

metr- (metro-) prefix

denoting the uterus.

Back  -    New Search

metralgia (mi-tral-ji) n.

pain in the uterus.

Back  -    New Search

metre (mee-ter) n.

the SI unit of length that is equal to 39.37 inches. Symbol: m.

Back  -    New Search

metritis (mi-try-tis) n.

inflammation of the uterus. See also ENDOMETRITIS, MYOMETRITIS.

Back  -    New Search

metronidazole (met-roh-ny-d-zohl) n.

a drug administered by mouth or in suppositories to treat infections of the urinary, genital, and digestive systems, such as trichomoniasis, amoebiasis, giardiasis, and acute ulcerative gingivitis. Trade names: Flagyl , Metrozol .

Back  -    New Search

metropathia haemorrhagica (met-roh-path-i hem--rah-jik-) n.

irregular episodes of bleeding from the uterus, without previous ovulation, due to excessive oestrogenic activity. It is associated with endometrial hyperplasia and usually with follicular cysts of the ovary.

Back  -    New Search

metrorrhagia (met-roh-ray-ji) n.

bleeding from the uterus other than the normal menstrual periods. It may indicate serious disease and should always be investigated.

Back  -    New Search

-metry suffix

denoting measuring or measurement.

Back  -    New Search

metyrapone (mi-ty-r-pohn) n.

a drug that interferes with the production of the hormones cortisol and aldosterone and is used in the treatment of Cushing's syndrome. It is administered by mouth. Trade name: Metopirone .

Back  -    New Search

mexiletine (meks-il-i-teen) n.

an anti-arrhythmic drug used in the treatment or prevention of severe heart irregularity arising in the lower chambers (ventricles). It is administered by mouth. Trade name: Mexitil .

Back  -    New Search

mianserin (mi-an-ser-in) n.

a drug administered by mouth to relieve moderate or severe depression and anxiety. Trade names: Bolvidon , Norval .

Back  -    New Search

Michel's clips (mee-shelz) pl. n.

small metal clips used for suturing surgical wounds. [G. Michel (1875–1937), French surgeon]

Back  -    New Search

miconazole (mi-kon--zohl) n.

a drug used to treat fungal infections, such as ringworm of the scalp, body, and feet, and candidosis. It is administered by intravenous injection, intravaginally, or topically. Trade names: Daktarin , Gyno-Daktarin .

Back  -    New Search

micr- (micro-) prefix

denoting 1 small size.

2 one millionth part.
Top

Back  -    New Search

microaneurysm (my-kroh-an-yoor-izm) n.

a minute localized swelling of a capillary wall, which is found in the retina of patients with diabetic retinopathy.

Back  -    New Search

microangiopathy (my-kroh-an-ji-op--thi) n.

damage to the walls of the smallest blood vessels. It may result from a variety of diseases, including diabetes mellitus, connective-tissue diseases, infections, and cancer.

Back  -    New Search

microbe (my-krohb) n.

see MICROORGANISM.

Back  -    New Search

microbiology (my-kroh-by-ol-ji) n.

the science of microorganisms. Microbiology in relation to medicine is concerned mainly with the isolation and identification of the microorganisms that cause disease.
—microbiological adj.—microbiologist n.

Back  -    New Search

microcephaly (my-kroh-sef-li) n.

abnormal smallness of the head: a congenital condition in which the brain is not fully developed. Compare MACROCEPHALY.

Back  -    New Search

microcheilia (my-kroh-ky-li) n.

abnormally small size of the lips. Compare MACROCHEILIA.

Back  -    New Search

Micrococcus (my-kroh-kok-s) n.

a genus of spherical Gram-positive bacteria occurring in colonies. They are saprophytes or parasites. M. tetragenus a species that can cause arthritis, endocarditis, meningitis, or abscesses in tissues.

Back  -    New Search

microcyte (my-kroh-syt) n.

an abnormally small red blood cell (erythrocyte). See also MICROCYTOSIS.
—microcytic adj.

Back  -    New Search

microcytosis (my-kroh-sy-toh-sis) n.

the presence of microcytes in the blood. Microcytosis is a feature of certain anaemias (microcytic anaemias ), including those due to iron deficiency.

Back  -    New Search

microdactyly (my-kroh-dak-tili) n.

abnormal smallness or shortness of the fingers.

Back  -    New Search

microdiscectomy (my-kroh-disk-ek-tmi) n.

surgical removal of all or part of a prolapsed intervertebral disc using an operating microscope. It is a form of minimally invasive surgery.

Back  -    New Search

microdissection (my-kroh-dis-sek-shn) n.

the process of dissecting minute structures under the microscope. Using this technique it is possible to dissect the nuclei of cells and even to separate individual chromosomes. See also MICROSURGERY.

Back  -    New Search

microdochectomy (my-kroh-dok-ek-tmi) n.

an exploratory operation on the mammary ducts, usually to detect (or exclude) the presence of a suspected tumour (adenoma).

Back  -    New Search

microdontia (my-kroh-don-ti) n.

a condition in which the teeth are unusually small.

Back  -    New Search

microfilaria (my-kroh-fil-air-i) n. (pl. microfilariae)

the slender motile embryo of certain nematodes (see FILARIA). Microfilariae are commonly found in the circulating blood or lymph of patients suffering an infection with any of the filarial worms.

Back  -    New Search

microglossia (my-kroh-glos-i) n.

abnormally small size of the tongue.

Back  -    New Search

micrognathia (my-kroh-nay-thi) n.

a condition in which one or both jaws are unusually small.

Back  -    New Search

microgram (my-kroh-gram) n.

one millionth of a gram. Symbol: µg.

Back  -    New Search

micrograph (photomicrograph) (my-kroh-graf) n.

a photograph of an object viewed through a microscope. electron m. a micrograph that is photographed through an electron microscope. light m. a micrograph that is photographed through a light microscope.

Back  -    New Search

micromanipulation (my-kroh-m-nip-yoo-lay-shn) n.

the manipulation of extremely small structures under the microscope, as in microdissection or microsurgery.

Back  -    New Search

micromelia (my-kroh-mee-li) n.

abnormally small size of the arms or legs. Compare MACROMELIA.

Back  -    New Search

micrometastasis (my-kroh-mi-tas-t-sis) n. (pl. micrometastases)

a secondary tumour that is undetectable by clinical examination or diagnostic tests but is visible under the microscope.

Back  -    New Search

micrometer (my-krom-it-er) n.

an instrument for making extremely fine measurements of thickness or length.

Back  -    New Search

micrometre (my-kroh-mee-ter) n.

one millionth of a metre (10-6 m). Symbol: µm.

Back  -    New Search

microorganism (microbe) (my-kroh-or-gn-izm) n.

any organism too small to be visible to the naked eye. Microorganisms include bacteria, some fungi, mycoplasmas, protozoa, rickettsiae, and viruses.

Back  -    New Search

microphthalmia (my-krof-thal-mi) n.

a congenitally small eye, usually associated with a small eye socket.

Back  -    New Search

micropsia (my-krop-si) n.

a condition in which objects appear smaller than they really are. It is usually due to disease of the retina.

Back  -    New Search

microscope (my-kr-skohp) n.

an instrument for producing a greatly magnified image of an object, which may be so small as to be invisible to the naked eye. See also ELECTRON MICROSCOPE, OPERATING MICROSCOPE.
—microscopical adj.—microscopy (my-kros-k-pi) n.

Back  -    New Search

microscopic (my-kr-skop-ik) adj.

1 too small to be seen clearly without the use of a microscope.

2 of, relating to, or using a microscope.
Top

Back  -    New Search

microsonation (my-kroh-sn-ay-shn) n.

the use of ultrasound waves generated inside the body from an extremely small source. This technique is used to obtain a picture of the fine structure of the neighbouring tissues.

Back  -    New Search

Microsporum (my-kroh-spor-m) n.

a genus of fungi causing tinea (ringworm). See also DERMATOPHYTE.

Back  -    New Search

microsurgery (my-kroh-ser-jer-i) n.

the branch of surgery in which extremely intricate operations are performed through highly refined operating microscopes using miniaturized precision instruments. The technique enables surgery of previously inaccessible parts of the eye, inner ear, spinal cord, and brain.

Back  -    New Search

microtome (my-kr-tohm) n.

an instrument for cutting extremely thin slices of material that can be examined under a microscope.

Back  -    New Search

microvascular (my-kroh-vas-kew-ler) adj.

involving small vessels. The term is often applied to techniques of microsurgery for reuniting small blood vessels (the same techniques are applied frequently to nerve suture).

Back  -    New Search

microwave therapy (my-kroh-wayv) n.

a form of diathermy using electromagnetic waves of extremely short wavelength.

Back  -    New Search

micturating cystourethrogram (MCU) (mik-tewr-ayt-ing sist-oh-yoor-ee-throh-gram) n.

an X-ray recording of the bladder and urethra taken during the voiding of water-soluble contrast material that has been previously inserted into the bladder. It demonstrates disorders of micturition.

Back  -    New Search

micturition (mik-tewr-ish-n) n.

see URINATION.

Back  -    New Search

midazolam (mid-az-oh-lam) n.

a benzodi-azepine drug used as a sedative for minor surgery, as a premedication, and to induce general anaesthesia. It is administered by injection. Trade name: Hypnovel .

Back  -    New Search

midbrain (mesencephalon) (mid-brayn) n.

the small portion of the brainstem, excluding the pons and the medulla, that joins the hindbrain to the forebrain.

Back  -    New Search

middle ear (tympanic cavity) (mi-d'l) n.

the air-filled part of the ear that transmits vibrations from the eardrum to the inner ear via three small bones (see OSSICLE). It is connected to the pharynx by the Eustachian tube.

Back  -    New Search

midgut (mid-gut) n.

the middle portion of the embryonic gut, which gives rise to most of the small intestine and part of the large intestine.

Back  -    New Search

midstream specimen of urine (MSU) (mid-streem) n.

a specimen of urine that is subjected to examination for the presence of microorganisms. In order to obtain a specimen that is free of contamination, the periurethral area is cleansed and the patient is requested to discard the initial flow of urine before collecting the specimen in a sterile container.

Back  -    New Search

midwife (mid-wyf) n.

(in Britain) a registered nurse who, having undertaken an additional training, is qualified to attend professionally upon a woman during the antenatal, intranatal, and postnatal periods. See also COMMUNITY MIDWIFE.
—midwifery (mid-wif-ri) n.

Back  -    New Search

mifepristone (mi-fep-ris-tohn) n.

a drug used to produce an abortion within the first 63 days of pregnancy: it acts by blocking the action of progesterone, which is essential for maintaining pregnancy. A second drug, one of the prostaglandins (e.g. gemeprost), is usually taken within 48 hours to complete the expulsion of the fertilized egg cell.

Back  -    New Search

migraine (mee-grayn) n.

a condition resulting from spasm and subsequent overdilatation of certain arteries in the brain, which causes a recurrent throbbing headache that characteristically affects one side of the head. The headache is often accompanied by prostration, nausea and vomiting, and photophobia. There is sometimes a preceding aura, consisting of visual disturbance or numbness and/or weakness of the limbs.
—migrainous adj.

Back  -    New Search

Mikulicz's disease (mik-oo-lich-iz) n.

damage to the lacrimal and salivary glands resulting in enlargement of these glands, narrowing of the corners of the eyes, conjunctivitis, and dryness of the mouth. The cause may be autoimmune disease or malignancy. [J. von Mikulicz Radecki (1850–1905), Polish surgeon]

Back  -    New Search

miliaria (mili-air-i) n.

see PRICKLY HEAT.

Back  -    New Search

miliary (mil-yer-i) adj.

describing or characterized by very small nodules or lesions, resembling millet seed. m. tuberculosis see TUBERCULOSIS.

Back  -    New Search

milium (mil-im) n. (pl. milia)

a white nodule in the skin, particularly on the face. Up to 2 mm in diameter, milia are tiny keratin cysts occurring just beneath the epidermis. Milia are commonly seen in newborn babies around the nose; they disappear without active treatment.

Back  -    New Search

milk (milk) n.

the liquid food secreted by female mammals from the mammary gland. Milk is a complete food in that it has most of the nutrients necessary for life: protein, carbohydrate, fat, minerals, and vitamins. Cows' milk is comparatively deficient in vitamins C and D. Human milk contains more sugar (lactose) and less protein than cows' milk.

Back  -    New Search

milk rash n.

a spotty red facial rash that is common during the first few months of life; it disappears without treatment.

Back  -    New Search

milk sugar n.

see LACTOSE.

Back  -    New Search

milk teeth pl. n.

the primary teeth of young children. See DENTITION.

Back  -    New Search

Miller-Abbott tube (mil-er ab-t) n.

a double-channel rubber tube used to relieve obstruction of the small intestine. One channel terminates in a balloon that is inflated when the tube reaches the duodenum; the other is used for suction of the obstructing material. [T. G. Miller (1886–1981) and W. O. Abbott (1902–43), US physicians]

Back  -    New Search

milli- prefix

denoting one thousandth part.

Back  -    New Search

milliampere (mili-am-pair) n.

one thousandth of an ampere (10-3 A). Symbol: mA.

Back  -    New Search

milligram (mil-i-gram) n.

one thousandth of a gram. Symbol: mg.

Back  -    New Search

millilitre (mil-i-lee-ter) n.

one thousandth of a litre. Symbol: ml.

Back  -    New Search

millimetre (mil-i-mee-ter) n.

one thousandth of a metre (10-3 m). Symbol: mm.

Back  -    New Search

Milroy's disease (mil-roiz) n.

congenital lymphoedema of the legs. See LYMPH-OEDEMA. [W. F. Milroy (1855–1942), US physician]

Back  -    New Search

Milton (mil-tn) n.

Trademark. a solution of sodium hypochlorite, used especially for sterilizing babies' feeding bottles.

Back  -    New Search

mineralocorticoid (min-er-l-oh-kor-ti-koid) n.

any of a group of corticosteroids, such as aldosterone, that are necessary for the regulation of salt and water balance.

Back  -    New Search

miner's elbow (my-nerz) n.

inflammation of the bursa over the elbow, caused by pressure on the olecranon process.

Back  -    New Search

minim (min-im) n.

a unit of volume used in pharmacy, equivalent to one sixtieth part of a fluid drachm.

Back  -    New Search

minimally invasive surgery (min-i-mli) n.

surgical intervention involving the least possible physical trauma to the patient, particularly surgery performed using an operating laparoscope or other endoscope (see LAPAROSCOPY) passed through a tiny incision; it is known popularly as keyhole surgery . Several types of abdominal surgery, including gall bladder removal (see CHOLECYSTECTOMY), are now commonly performed in this way.

Back  -    New Search

minitracheostomy (min-i-tray-ki-ost-mi) n.

temporary tracheostomy using a needle or fine-bore tube inserted through the skin.

Back  -    New Search

minocycline (min-oh-sy-kleen) n.

a tetra-cycline antibiotic active against a wide range of bacteria and against rickettsial infections, mycoplasmal pneumonia, and relapsing fever. It is administered by mouth and by intravenous injection. Trade name: Minocin .

Back  -    New Search

minoxidil (min-oks-i-dil) n.

a peripheral vasodilator used in the treatment of high blood pressure (hypertension) when other drugs are not effective; it is administered by mouth in conjunction with a diuretic. It is also applied to the scalp, in the form of a lotion, to restore hair growth. Trade names: Loniten , Regaine .

Back  -    New Search

mio- prefix

denoting 1 reduction or diminution.

2 rudimentary.
Top

Back  -    New Search

miosis (myosis) (my-oh-sis) n.

constriction of the pupil. This occurs normally in bright light, but persistent miosis is most commonly caused by certain types of eye drops used to treat glaucoma. See also MI-OTIC. Compare MYDRIASIS.

Back  -    New Search

miotic (myotic) (my-ot-ik) n.

a drug, such as physostigmine or pilocarpine, that causes the pupil of the eye to contract.

Back  -    New Search

miscarriage (mis-ka-rij) n.

see ABORTION.

Back  -    New Search

miso- prefix

denoting hatred.

Back  -    New Search

misoprostol (mis-op-r-stol) n.

a prostaglandin drug used in the prevention and treatment of peptic ulcer caused by nonsteroidal anti-inflammatory drugs (see NSAID). It is administered by mouth. Trade names: Cytotec , Napratec .

Back  -    New Search

missed case n.

a person suffering from an infection in whom the symptoms and signs are so minimal that either there is no request for medical assistance or the doctor fails to make the diagnosis.

Back  -    New Search

Misuse of Drugs Act 1971 n.

(in the UK) an Act of Parliament restricting the prescription, dispensing, sale, and possession of dangerous drugs. These controlled drugs include the natural opiates and their synthetic substitutes, many stimulants (including amphetamine, cocaine, and pemoline), and hallucinogens such as LSD and cannabis.

Back  -    New Search

mite (myt) n.

a free-living or parasitic arthropod belonging to a group (Acarina) that also includes the ticks. Medically important mites include the many species causing dermatitis (e.g. Dermatophagoides).

Back  -    New Search

mithramycin (plicamycin) (mith-r-my-sin) n.

an antibiotic that prevents the growth of cancer cells. It is now used to reduce high levels of calcium in the blood.

Back  -    New Search

mitochondrion (my-toh-kon-dri-n) n. (pl. mitochondria)

a structure, occurring in varying numbers in the cytoplasm of every cell, that is the site of the cell's energy production. Mitochondria contain ATP and the enzymes involved in the cell's metabolic activities.
—mitochondrial adj.

Back  -    New Search

mitomycin C (my-toh-my-sin) n.

an antibiotic that inhibits the growth of cancer cells. It causes severe marrow suppression but is of use in the treatment of stomach and breast cancers. Trade name: Mutamycin .

Back  -    New Search

mitosis (my-toh-sis) n.

a type of cell division in which a single cell produces two genetically identical daughter cells. It is the way in which new body cells are produced for both growth and repair. Compare MEIOSIS.
—mitotic (my-tot-ik) adj.

Back  -    New Search

mitoxantrone (mi-toks-an-trohn) n.

a drug used in the treatment of certain cancers, including breast cancer, leukaemia, and lymphomas. Trade name: Novantrone .

Back  -    New Search

mitral incompetence (my-trl) n.

failure of the mitral valve to close, allowing a reflux of blood from the left ventricle of the heart to the left atrium. Its manifestations include breathlessness, atrial fibrillation, embolism, enlargement of the left ventricle, and a systolic murmur.

Back  -    New Search

mitral stenosis n.

narrowing of the opening of the mitral valve: a result of chronic scarring that follows rheumatic fever. Mild cases need no treatment, but severe cases are treated surgically by reopening the stenosis (mitral valvotomy ) or by inserting an artificial valve (mitral prosthesis ).

Back  -    New Search

mitral valve (bicuspid valve) n.

a valve in the heart consisting of two cusps attached to the walls at the opening between the left atrium and left ventricle. It allows blood to pass from the atrium to the ventricle, but prevents any backward flow.

Back  -    New Search

mittelschmerz (mit-l-shmairts) n.

pain in the lower abdomen experienced about midway between successive menstrual periods, i.e. at ovulation.

Back  -    New Search

ml

abbrev. for millilitre.

Back  -    New Search

MLD n.

minimal lethal dose: the smallest quantity of a toxic compound that is recorded as having caused death.

Back  -    New Search

MM n.

malignant melanoma: see MELANOMA.

Back  -    New Search

MMR vaccine n.

a combined vaccine against measles, mumps, and German measles (rubella). It is currently recommended that this vaccine is given to all children between 13 and 15 months old, with a subsequent booster dose.

Back  -    New Search

MND n.

see MOTOR NEURONE DISEASE.

Back  -    New Search

moclobemide (mok-loh-bi-myd) n.

an antidepressant drug that reversibly inhibits the enzyme monoamine oxidase. It is less likely to cause the adverse effects associated with traditional MAO inhibitors.

Back  -    New Search

modality (moh-dal-iti) n.

1 a form of sensation, such as smell, hearing, tasting, or detecting temperature.

2 one form of therapy as opposed to another, such as the modality of physiotherapy contrasted with that of radiotherapy.
Top

Back  -    New Search

Modecate (mod-i-kayt) n.

see FLUPHENAZINE.

Back  -    New Search

modelling (mod-l-ing) n.

a technique used in behaviour modification, whereby an individual learns a behaviour by observing someone else doing it.

Back  -    New Search

modiolus (moh-dy-oh-ls) n.

the conical central pillar of the cochlea in the inner ear.

Back  -    New Search

MODS n.

see MULTIPLE ORGAN DYSFUNCTION SYNDROME.

Back  -    New Search

MOF n.

see MULTIPLE-ORGAN FAILURE.

Back  -    New Search

Mogadon (mog--don) n.

see NITRAZEPAM.

Back  -    New Search

molar (moh-ler) n.

the fourth or fifth tooth (in the primary dentition) or the sixth, seventh, or eighth tooth (in the permanent dentition) from the midline on each side of each jaw. See also DENTITION.

Back  -    New Search

molarity (mol-a-ri-ti) n.

the strength of a solution, expressed as the weight of dissolved substance in grams per litre divided by its molecular weight, i.e. the number of moles per litre.

Back  -    New Search

mole^1 (mohl) n.

the SI unit of amount of substance. One mole of a compound has a mass equal to its molecular weight expressed in grams. Symbol: mol.

Back  -    New Search

mole^2 n.

a nonmalignant collection of pigmented cells in the skin. Moles vary widely in appearance, being flat or raised, smooth or hairy. Changes in the shape, colour, etc., of moles in adult life may be an early sign of malignant melanoma. Medical name: pigmented naevus .

Back  -    New Search

molecular biology (m-lek-yoo-ler) n.

the study of the molecules that are associated with living organisms, especially proteins and nucleic acids.

Back  -    New Search

molecule (mol-i-kewl) n.

a particle consisting of two or more atoms held together by chemical bonds. It is the smallest unit of an element or compound capable of existing independently.
—molecular adj.

Back  -    New Search

molluscum contagiosum (mol-usk-m kon-ta-joh-sm) n.

a common disease of the skin, mainly affecting children. Characterized by papules less than 5 mm in diameter, each with a central depression, the disease is caused by a poxvirus and is spread by direct contact. Untreated. the papules disappear in 6–9 months.

Back  -    New Search

mon- (mono-) prefix

denoting one, single, or alone.

Back  -    New Search

Mönckeberg's arteriosclerosis (or degeneration) (mernk-i-bergz) n.

see ARTERIOSCLEROSIS. [J. G. Mönckeberg (1877–1925), German pathologist]

Back  -    New Search

Mongolian blue spots (mong-oh-lin) pl.

n. blue-black pigmented areas seen at the base of the back and on the buttocks of babies. They are more common in Asian babies and usually fade during the first year of life.

Back  -    New Search

mongolism (mong--lizm) n.

see DOWN'S SYNDROME.

Back  -    New Search

Monilia (moh-nil-i) n.

the former name of the genus of yeasts now known as Candida.

Back  -    New Search

moniliasis (mon-i-ly--sis) n.

an obsolete name for candidosis.

Back  -    New Search

Monitor (mon-i-ter) n.

see QUALITY ASSURANCE (TOOL).

Back  -    New Search

monitoring (mon-i-ter-ing) n.

the periodic observation of a patient's condition, which may be by visual, manual, or automatic means.

Back  -    New Search

monoamine oxidase (MAO) (mon-oh-ay-meen) n.

an enzyme that catalyses the oxidation of a large variety of monoamines, including adrenaline, nor-adrenaline, and serotonin. Monoamine oxidase is found in most tissues, particularly the liver and nervous system. See also MAO INHIBITOR.

Back  -    New Search

monoblast (mon-oh-blast) n.

the earliest identifiable cell that gives rise to a monocyte. It is normally found in the blood-forming tissue of the bone marrow but may appear in the blood in certain diseases, most notably in acute monoblastic leukaemia .

Back  -    New Search

monochromat (mon-oh-kroh-mat) n.

a person who is completely colour-blind. The condition is probably inherited.

Back  -    New Search

monochromatic (mon-oh-kr-mat-ik) adj.

denoting radiation, especially light, of the same frequency or wavelength.

Back  -    New Search

monoclonal antibody (mon-oh-kloh-nl) n.

an antibody produced artificially from a cell clone and therefore consisting of a single type of immunoglobulin. Monoclonal antibodies are produced by fusing antibody-forming lymphocytes from mouse spleen with mouse myeloma cells. The resulting hybrid cells multiply rapidly (like cancer cells) and produce the same antibody as their parent lymphocytes.

Back  -    New Search

monocular (mon-ok-yoo-ler) adj.

relating to or used by one eye only. Compare BINOCULAR.

Back  -    New Search

monocyte (mon-oh-syt) n.

a variety of white blood cell with a kidney-shaped nucleus. Its function is the ingestion of foreign particles, such as bacteria and tissue debris.
—monocytic adj.

Back  -    New Search

monocytosis (mon-oh-sy-toh-sis) n.

an increase in the number of monocytes in the blood. Monocytosis occurs in a variety of diseases, including certain leukaemias (monocytic leukaemias ).

Back  -    New Search

monodactylism (mon-oh-dak-til-izm) n.

the congenital absence of all but one digit on each hand and foot.

Back  -    New Search

monomania (mon-oh-may-ni) n.

the state in which a particular delusion or set of delusions is present in an otherwise normally functioning person. See also PARANOIA.

Back  -    New Search

mononeuritis (mon-oh-newr-I-tis) n.

disease affecting a single peripheral nerve. Compare POLYNEUROPATHY.

Back  -    New Search

mononuclear (mon-oh-new-kli-er) adj.

(of a cell) having one nucleus.

Back  -    New Search

mononucleosis (mon-oh-new-kli-oh-sis) n.

the condition in which the blood contains an abnormally high number of mononuclear leucocytes (monocytes). See GLANDULAR FEVER (INFECTIOUS MONONUCLEOSIS).

Back  -    New Search

monoplegia (mon-oh-plee-ji) n.

paralysis of one limb.
—monoplegic adj.

Back  -    New Search

monoploid (mon--ploid) adj.

see HAPLOID.

Back  -    New Search

monorchism (mon-or-kizm) n.

the absence of one testis. This is usually due to failure of one testicle to descend into the scrotum before birth.

Back  -    New Search

monosaccharide (mon-oh-sak--ryd) n.

a simple sugar having the general formula (CH_2O)n. The most abundant monosaccharide is glucose.

Back  -    New Search

monosomy (mon--soh-mi) n.

a condition in which there is one chromosome missing from the normal (diploid) set. Compare TRISOMY.
—monosomic adj.

Back  -    New Search

monozygotic twins (mon-oh-zy-got-ik) pl. n.

see TWINS.

Back  -    New Search

mons (monz) n.

(in anatomy) a rounded eminence. m. pubis the mound of fatty tissue lying over the pubic symphysis.

Back  -    New Search

monster (mon-ster) n.

a fetus or infant grossly malformed because of developmental abnormalities.

Back  -    New Search

Montgomery's glands (mnt-gom-er-iz) pl. n.

sebaceous glands on the areola surrounding the nipple of a woman's breast. They enlarge during pregnancy and their secretions lubricate and protect the breast during breast feeding. [W. F. Montgomery (1797–1859), Irish obstetrician]

Back  -    New Search

Mooren's ulcer (moor-nz) n.

a rare chronic progressive ulceration of the cornea, occurring in the elderly. It is typically very painful and difficult to control. [A. Mooren (1829–99), German ophthalmologist]

Back  -    New Search

morbid (mor-bid) adj.

diseased or abnormal; pathological.

Back  -    New Search

morbidity (mor-bid-iti) n.

the state of being diseased. m. rate the number of cases of a disease found to occur in a stated number of the population, usually given as cases per 100,000 or per million.

Back  -    New Search

morbilli (mor-bil-l) n.

see MEASLES.

Back  -    New Search

morbilliform (mor-bil-i-form) adj.

describing a skin rash resembling that of measles.

Back  -    New Search

morbus (mor-bs) n.

disease. The term is usually used as part of the medical name of a specific disease.

Back  -    New Search

moribund (mo-ri-bund) adj.

dying.

Back  -    New Search

morning sickness (mor-ning) n.

nausea and vomiting during early pregnancy. Compare HYPEREMESIS (GRAVIDARUM).

Back  -    New Search

Moro reflex (startle reflex) (moh-roh) n.

the normal reaction of a newborn baby to a sudden loud noise. The infant flings its arms and legs wide and appears to stiffen; the limbs are then drawn back into flexion. [E. Moro (1874–1951), German paediatrician]

Back  -    New Search

morphine (mor-feen) n.

a potent analgesic and narcotic drug administered by mouth or injection to relieve severe and persistent pain. Morphine causes feelings of euphoria; tolerance develops rapidly and dependence may occur.

Back  -    New Search

morpho- prefix

denoting form or structure.

Back  -    New Search

morphoea (mor-fee-) n.

a localized form of scleroderma characterized by firm ivory-coloured waxy plaques in the skin without any internal sclerosis.

Back  -    New Search

morphogenesis (mor-foh-jen-i-sis) n.

the development of form and structure of the body and its parts.

Back  -    New Search

morphology (mor-fol-ji) n.

the study of differences in form between species.

Back  -    New Search

-morphous suffix

denoting form or structure (of a specified kind).

Back  -    New Search

Morquio-Brailsford disease (mor-kee-oh-braylz-ferd) n.

a defect of mucopolysaccharide metabolism that causes dwarfism with a kyphosis, knock knees, and an angulated sternum. Intelligence is normal. [L. Morquio (1867–1935), Uruguayan physician; J. F. Brailsford (20th century), British radiologist]

Back  -    New Search

mortality (mortality rate) (mor-tal-iti) n.

the incidence of death in the population in a given period. annual m. rate the number of registered deaths in a year, multiplied by 1000 and divided by the population at the middle of the year. See also INFANT (MORTALITY RATE), MATERNAL MORTALITY RATE.

Back  -    New Search

mortification (mor-ti-fi-kay-shn) n.

see NECROSIS.

Back  -    New Search

morula (mo-roo-l) n.

an early stage of embryonic development formed by cleavage of the fertilized ovum. It consists of a solid ball of cells and is an intermediate stage between the zygote and blastocyst.

Back  -    New Search

mosaicism (m-zay-i-sizm) n.

a condition in which the cells of an individual do not all contain identical chromosomes; there may be two or more genetically different populations of cells.
—mosaic adj.

Back  -    New Search

mosquito (mos-kee-toh) n.

a small winged bloodsucking insect belonging to a large group – the Diptera. Female mosquitoes transmit the parasites responsible for several major infectious diseases, such as malaria. See ANOPHELES, AËDES.

Back  -    New Search

motile (moh-tyl) adj.

being able to move spontaneously, without external aid: usually applied to a microorganism or a cell.

Back  -    New Search

motions (moh-shnz) pl.

n. the products of bowel evacuation.

Back  -    New Search

motion sickness (travel sickness) (moh-shn) n.

nausea, vomiting, and headache caused by motion during travel by sea, road, or air. The symptoms are due to overstimulation of the balance organs in the inner ear. Sedative antihistamine drugs are used for prevention and treatment.

Back  -    New Search

motor cortex (moh-ter) n.

the region of the cerebral cortex that is responsible for initiating nerve impulses that bring about voluntary activity in the muscles of the body.

Back  -    New Search

motor nerve n.

see NERVE.

Back  -    New Search

motor neurone n.

one of the units (neurones) that goes to make up the nerve pathway between the brain and an effector organ, such as a skeletal muscle. lower m. n. a motor neurone that has a cell body in the spinal cord or brainstem and an axon that extends outwards to reach an effector. upper m. n. a motor neurone that has a cell body in the brain and an axon that extends into the spinal cord, where it ends in synapses.

Back  -    New Search

motor neurone disease (MND) n.

a progressive degenerative disease of the motor system occurring in middle age and causing muscle weakness and wasting. It primarily affects the cells of the anterior horn of the spinal cord, the motor nuclei in the brainstem, and the corticospinal fibres. Some forms of the disease are familial (inherited).

Back  -    New Search

mould (mohld) n.

any multicellular filamentous fungus that commonly forms a rough furry coating on decaying matter.

Back  -    New Search

moulding (mohld-ing) n.

the changing of the shape of an infant's head during labour, brought about by the pressures to which it is subjected when passing through the birth canal.

Back  -    New Search

mountain sickness (mownt-in) n.

see ALTITUDE SICKNESS.

Back  -    New Search

mouth-to-mouth respiration (mowth) n.

emergency artificial respiration, performed mouth-to-mouth, by blowing air into the victim's lungs to inflate them and then allowing exhalation to occur automatically. It is commonly known as the kiss of life .

Back  -    New Search

mouthwash (mowth-wosh) n.

an aqueous solution with antiseptic, astringent, or deodorizing properties used for rinsing of the mouth and teeth. m. test a test for detecting carriers of single-gene defects (e.g. cystic fibrosis) in which cells from the buccal cavity are obtained from a saline mouthwash and their DNA is isolated and genetically analysed.

Back  -    New Search

MRI n.

see MAGNETIC RESONANCE IMAGING.

Back  -    New Search

MRSA n.

methicillin- (or multiple-)resistant Staphylococcus aureus: an increasingly common dangerous bacterium that is resistant to many antibiotics and is responsible for outbreaks of infection in hospitals.

Back  -    New Search

MS n.

see MULTIPLE SCLEROSIS.

Back  -    New Search

MSH n.

see MELANOCYTE-STIMULATING HORMONE.

Back  -    New Search

MSU n.

see MIDSTREAM SPECIMEN OF URINE.

Back  -    New Search

mucilage (mew-si-lij) n.

(in pharmacy) a thick aqueous solution of a gum used as a lubricant in skin preparations, for the production of pills, and for the suspension of insoluble substances.

Back  -    New Search

mucin (mew-sin) n.

the principal constituent of mucus. Mucin is a glycoprotein.

Back  -    New Search

muco- prefix

denoting 1 mucus.

2 mucous membrane.
Top

Back  -    New Search

mucociliary transport (mew-koh-sil-i-er-i) n.

the process by which cilia move a thin film of mucus from the upper and lower respiratory tracts towards the digestive tract. Particles of dust and microorganisms are trapped on the mucus and thereby removed from the respiratory tract.

Back  -    New Search

mucocoele (mew-koh-seel) n.

a space or organ distended with mucus. It may occur in the gall bladder when the exit duct becomes obstructed.

Back  -    New Search

mucocutaneous (mew-koh-kew-tay-nis) adj.

relating to or affecting mucous membrane and skin.

Back  -    New Search

mucoid (mew-koid) adj.

resembling mucus.

Back  -    New Search

mucolytic (mew-koh-lit-ik) n.

an agent, such as tyloxapol, that dissolves or breaks down mucus. Mucolytics are used to treat chest conditions involving excessive or thickened mucus secretions.

Back  -    New Search

mucopolysaccharide (mew-koh-poli-sak-er-yd) n.

one of a group of complex carbohydrates functioning mainly as structural components in connective tissue.

Back  -    New Search

mucopolysaccharidosis (mew-koh-poli-sak-er-l-doh-sis) n.

any one of a group of eight rare inborn errors of metabolism in which the storage of complex carbohydrates is disordered. See HUNTER'S SYNDROME, HURLER'S SYNDROME.

Back  -    New Search

mucoprotein (mew-koh-proh-teen) n.

one of a group of proteins found in the globulin fraction of blood plasma. Mucoproteins are globulins combined with a carbohydrate group (an amino sugar).

Back  -    New Search

mucopurulent (mew-koh-pewr-oo-lnt) adj.

containing mucus and pus. See MUCOPUS.

Back  -    New Search

mucopus (mew-koh-pus) n.

a mixture of mucus and pus.

Back  -    New Search

mucosa (mew-koh-s) n.

see MUCOUS MEMBRANE.
—mucosal adj.

Back  -    New Search

mucous membrane (mucosa) (mew-ks) n.

the moist membrane lining many tubular structures and cavities, including the nasal sinuses, respiratory tract, gastrointestinal tract, biliary, and pancreatic systems. The surface layer of the membrane contains glands that secrete mucus.

Back  -    New Search

mucoviscidosis (mew-koh-vis-i-doh-sis) n.

see CYSTIC FIBROSIS.

Back  -    New Search

mucus (mew-ks) n.

a viscous fluid secreted by mucous membranes. Mucus acts as a protective barrier over the surfaces of the membranes, as a lubricant, and as a carrier of enzymes.
—mucous adj.

Back  -    New Search

MUGA scan (multiple-gated arteriography) (mug-) n.

a method of studying left-ventricular function and wall motion of the heart by injecting the patient's red cells with radioactive technetium-99 to form an image of the blood pool within the heart at specific points in the cardiac cycle, using an ECG, gamma camera, and computer.

Back  -    New Search

Müllerian duct (mew-leer-in) n.

see PARAMESONEPHRIC DUCT. [J. P. Müller (1801–58), German physiologist]

Back  -    New Search

multi- prefix

denoting many; several.

Back  -    New Search

multifactorial (multi-fak-tor-il) adj.

describing a condition, such as spina bifida, that is believed to have resulted from the interaction of genetic factors, usually polygenes, with an environmental factor or factors.

Back  -    New Search

multifocal lenses (multi-foh-kl) pl.

n. lenses in which the power (see DIOPTRE) of the lower part gradually increases towards the lower edge. The wearer can see clearly at any distance by lowering or raising his eyes to look through an appropriate part of the lens.

Back  -    New Search

multigravida (multi-grav-id-) n.

a woman who has been pregnant at least twice.

Back  -    New Search

multi-organ failure (MOF) (multi-or-gn) n.

the terminal stage of serious illness.

Back  -    New Search

multipara (mul-tip-er-) n.

a woman who has given birth to a live child after each of at least two pregnancies. See also GRAND MULTIPARITY.

Back  -    New Search

multiple myeloma (mul-ti-pl) n.

see MYELOMA.

Back  -    New Search

multiple organ dysfunction syndrome (MODS) n.

a common cause of death following severe injury, overwhelming infection, or immune deficiency states.

Back  -    New Search

multiple personality disorder n.

a psychiatric disorder in which the affected person has two or more distinct, and often contrasting, personalities. As each personality assumes dominance, it determines attitudes and behaviour and usually appears to be unaware of the other personality (or personalities). The condition is thought to be a late result of child abuse.

Back  -    New Search

multiple sclerosis (MS, disseminated sclerosis) n.

a chronic disease of the nervous system affecting young and middle-aged adults. The myelin sheaths surrounding nerves in the brain and spinal cord are damaged, which affects the function of the nerves involved. The course of the illness is usually characterized by recurrent relapses followed by remissions but a small proportion of patients run a chronic progressive course. Symptoms include ataxia, nystagmus, dysarthria, spastic weakness, and retrobulbar neuritis.

Back  -    New Search

multisystem (multi-sis-tm) adj.

describing a disease that affects many systems of the body.

Back  -    New Search

mummification (mum-i-fi-kay-shn) n.

the conversion of dead tissue into a hard shrunken mass, chiefly by dehydration.

Back  -    New Search

mumps (mumps) n.

a common virus infection mainly affecting children. Symptoms appear 2–3 weeks after exposure: fever, headache, and vomiting may precede a typical swelling of the parotid salivary glands. The infection may spread to other salivary glands and to the pancreas, brain, and testicles (see ORCHITIS). See also MMR VACCINE. Medical name: infectious parotitis .

Back  -    New Search

Munchausen's syndrome (muunch-how-znz) n.

a mental disorder in which the patient persistently tries to obtain hospital treatment, especially surgery, for an illness that is nonexistent: an extreme form of malingering. M. s. by proxy a condition in which the patient inflicts harm on others (often children) in order to attract medical attention. [Baron von Munchausen, a fictional character who told exaggerated stories]

Back  -    New Search

murmur (bruit) (mer-mer) n.

a noise, heard with the aid of a stethoscope, that is generated by turbulent blood flow within the heart or blood vessels produced by damaged valves, septal defects, narrowed arteries, or arteriovenous communications. continuous m. murmur heard throughout systole and diastole. diastolic m. murmur heard during diastole. innocent m. heart murmur heard in normal individuals. systolic m. murmur heard during systole.

Back  -    New Search

Murphy's sign (mer-fiz) n.

an indication of an inflamed gall bladder: continuous pressure over the gall bladder will cause the patient to catch his breath just before the peak of inhalation. [J. B. Murphy (1857–1916), US surgeon]

Back  -    New Search

muscae volitantes (mus-kee vol-i-tan-teez) pl. n.

black spots seen floating before the eyes usually due to the presence of opacities in the vitreous humour as it becomes more fluid with age.

Back  -    New Search

muscarine (musk-er-in) n.

a highly poisonous alkaloid occurring in certain mushrooms, such as fly agaric (Amanita muscaria).

Back  -    New Search

muscle (mus-l) n.

a tissue whose cells have the ability to contract, producing movement or force. The major functions of muscles are to produce movements of the body and of structures within it and to alter pressures or tensions of internal organs. There are three types of muscle (see CARDIAC MUSCLE, SMOOTH MUSCLE, STRIATED MUSCLE). See illustration.

—muscular (mus-kew-ler) adj.

Back  -    New Search

muscle relaxant n.

an agent that reduces tension in muscles. Drugs such as diazepam are used to relieve skeletal muscular spasms in conditions such as parkinsonism. Other drugs, e.g. alcuronium, gallamine, and tubocurarine, are used to relax voluntary muscles during the administration of anaesthetics in surgical operations.

Back  -    New Search

muscular dystrophy n.

a group of muscle diseases, marked by weakness and wasting of selected muscles, in which there is a recognizable pattern of inheritance. The affected muscle fibres degenerate and are replaced by fatty tissue. The most common form is Duchenne muscular dystrophy , which is nearly always restricted to boys and usually begins before the age of four. The child has a waddling gait and lordosis of the lumbar spine. The calf muscles – and later the shoulders and upper limbs – often become firm and bulky. See also BECKER MUSCULAR DYSTROPHY, DYSTROPHIA MYOTONICA (MYOTONIC DYSTROPHY).

Back  -    New Search

muscularis (mus-kew-lar-is) n.

a muscular layer of the wall of a hollow organ (such as the stomach) or a tubular structure (such as the ureter or intestine).

Back  -    New Search

musculo- prefix

denoting muscle.

Back  -    New Search

musculocutaneous nerve (mus-kew-loh-kew-tay-nis) n.

a nerve of the brachial plexus that supplies some muscles of the arm and the skin of the lateral part of the forearm.

Back  -    New Search

musculoskeletal (mus-kew-loh-skel-i-t'l) adj.

relating to both the muscles and the bones.

Back  -    New Search

mushroom (mush-room) n.

the spore-producing body of various fungi. Great care must be taken in identifying edible mushrooms, as many species are poisonous (see AMANITA).

Back  -    New Search

mustine (nitrogen mustard) (must-een) n.

a drug administered by injection to treat various types of cancer, including Hodgkin's disease and some types of leukaemia.

Back  -    New Search

mutant (mew-tnt) n.

1 an individual in which a mutation has occurred, especially when the effect of the mutation is visible.

2 a characteristic showing the effects of a mutation.
Top

—mutant adj.

Back  -    New Search

mutation (mew-tay-shn) n.

a change in the amount or structure of the genetic material (DNA) of a cell, or the change this causes in a characteristic of the individual. A mutation affecting developing sex cells can be inherited. Mutations may occur spontaneously or be caused by external agents (e.g. radiation or certain viruses).

Back  -    New Search

mutism (mewt-izm) n.

inability or refusal to speak; dumbness. Innate speechlessness most commonly occurs in those who have been totally deaf since birth (deaf m. ). Mutism may also result from brain damage (see APHASIA) or be caused by depression or psychological trauma.
—mute adj., n.

Back  -    New Search

my- (myo-) prefix

denoting muscle.

Back  -    New Search

myalgia (my-al-ji) n.

pain in the muscles.
—myalgic (my-al-jik) adj.

Back  -    New Search

myalgic encephalomyelitis (ME) n.

see CHRONIC FATIGUE SYNDROME.

Back  -    New Search

myasthenia (my-s-th'ee-ni) n.

weakness of the muscles. m. gravis a chronic disease marked by abnormal fatigability and weakness of selected muscles, initially those around the eyes, mouth, and throat, resulting in drooping of the upper eyelid (ptosis), double vision, and dysarthria. It is an autoimmune disease in which the ability of the neurotransmitter acetylcholine to induce muscular contraction is impaired. Drug treatment and surgical removal of the thymus lessen the severity of the symptoms. Steroid therapy or plasma exchange may be used to treat the more severely affected patients.

Back  -    New Search

myc- (myco-, mycet(o)-) prefix

denoting a fungus.

Back  -    New Search

mycelium (my-see-lim) n. (pl. mycelia)

the tangled mass of fine branching threads that make up the feeding and growing part of a fungus.

Back  -    New Search

mycetoma (my-si-toh-m) n.

a chronic inflammation of tissues caused by a fungus. See MADURA FOOT.

Back  -    New Search

Mycobacterium (my-koh-bak-teer-im) n.

a genus of rodlike aerobic Gram-positive bacteria. Several species are responsible for opportunistic infections of the lung (see MAI COMPLEX). M. leprae (Hansen's bacillus ) the species that causes leprosy. M. tuberculosis (Koch's bacillus ) the species that causes tuberculosis.

Back  -    New Search

mycology (my-kol-ji) n.

the science of fungi. See also MICROBIOLOGY.
—mycologist n.

Back  -    New Search

mycoplasma (my-koh-plaz-m) n.

one of a group of minute non-motile microorganisms that lack a rigid cell wall and hence display a variety of forms. The species Mycoplasma pneumoniae causes atypical pneumonia. The group also includes the pleuropneumonia-like organisms (PPLO).

Back  -    New Search

mycosis (my-koh-sis) n.

any disease caused by a fungus, including actinomycosis, aspergillosis, cryptococcosis, rhinosporidiosis, ringworm, and sporotrichosis.

Back  -    New Search

mycosis fungoides (fung-oid-eez) n.

a variety of reticulosis confined to the skin, with plaques and later nodules infiltrated with T-lymphocytes. It progresses very slowly and can be treated initially with topical corticosteroids.

Back  -    New Search

Mycota (my-koh-ta) n.

see UNDECENOIC ACID.

Back  -    New Search

mydriasis (mid-ry--sis) n.

widening of the pupil, which occurs normally in dim light. The commonest cause of prolonged mydriasis is drug therapy (see MYDRIATIC) or injury to the eye. See also CYCLOPLEGIA. Compare MIOSIS.

Back  -    New Search

mydriatic (mid-ri-at-ik) n.

a drug, such as atropine or phenylephrine, that causes the pupil of the eye to dilate.

Back  -    New Search

myectomy (my-ek-tmi) n.

a surgical operation to remove part of a muscle.

Back  -    New Search

myel- (myelo-) prefix

denoting 1 the spinal cord.

2 bone marrow.
Top

3 myelin.
Top

Back  -    New Search

myelencephalon (my-l-en-sef--lon) n.

see MEDULLA (OBLONGATA).

Back  -    New Search

myelin (my--lin) n.

a complex material formed of protein and phospholipid that is laid down as a sheath around the axons of certain neurones, known as myelinated (or medullated ) nerve fibres .

Back  -    New Search

myelination (my--lin-ay-shn) n.

the process in which myelin is laid down as an insulating layer around the axons of certain nerves.

Back  -    New Search

myelitis (my--ly-tis) n.

1 an inflammatory disease of the spinal cord. The most usual kind (transverse m. ) most often occurs during the development of multiple sclerosis. The inflammation spreads across the tissue of the spinal cord, resulting in paralysis of the legs and lower trunk.

2 inflammation of the bone marrow. See OSTEOMYELITIS.
Top

Back  -    New Search

myeloblast (my--loh-blast) n.

the earliest identifiable cell that gives rise to a granulocyte. It is normally found in the blood-forming tissue of the bone marrow, but may appear in the blood in a variety of diseases, most notably in acute myeloblastic leukaemia . See also GRANULOPOIESIS.
—myeloblastic adj.

Back  -    New Search

myelocele (my--loh-seel) n.

see MENINGOMYELOCELE.

Back  -    New Search

myelocyte (my--loh-syt) n.

an immature form of granulocyte. It is normally found in the blood-forming tissue of the bone marrow, but may appear in the blood in a variety of diseases, including infections, infiltrations of the bone marrow, and certain leukaemias. See also GRANULOPOIESIS.

Back  -    New Search

myelofibrosis (my--loh-fy-broh-sis) n.

a chronic but progressive disease characterized by fibrosis of the bone marrow, which leads to anaemia; enlargement of the spleen; and the presence of myeloid tissue in abnormal sites, such as the spleen and liver. Its cause is unknown.

Back  -    New Search

myelography (my--log-rfi) n.

a specialized method of X-ray examination to demonstrate the spinal canal that involves injection of a radiopaque contrast medium into the subarachnoid space. The X-rays obtained are called myelograms .

Back  -    New Search

myeloid (my--loid) adj.

1 like, derived from, or relating to bone marrow. m. leukaemia a variety of leukaemia in which the type of blood cell that proliferates abnormally originates in the blood-forming tissue of the bone marrow. m. tissue a tissue in the bone marrow in which the various classes of blood cells are produced. See also HAEMOPOIESIS.

2 resembling a myelocyte.
Top

3 relating to the spinal cord.
Top

Back  -    New Search

myeloma (multiple myeloma, myelomatosis) (my--loh-m) n.

a malignant disease of the bone marrow, characterized by the presence of an excess of abnormal malignant plasma cells in the bone marrow. The patient may complain of tiredness due to anaemia and of bone pain and may develop pathological fractures. Treatment is usually with drugs, such as melphalan or cyclophosphamide, and radiotherapy. See also PLASMACYTOMA.

Back  -    New Search

myelomalacia (my--loh-m-lay-shi) n.

softening of the tissues of the spinal cord, most often caused by an impaired blood supply.

Back  -    New Search

myelomatosis (my--loh-m-toh-sis) n.

see MYELOMA.

Back  -    New Search

myelomeningocele (my--loh-min-ing-oh-seel) n.

see MENINGOMYELOCELE.

Back  -    New Search

myelosuppression (my--loh-s-presh-n) n.

a reduction in blood-cell production by the bone marrow. It commonly occurs after chemotherapy and may result in anaemia, infection, and abnormal bleeding (see THROMBOCYTOPENIA, NEUTROPENIA).
—myelosuppressive adj.

Back  -    New Search

myenteron (my-en-ter-on) n.

the muscular layer of the intestine, consisting of a layer of circular muscle inside a layer of longitudinal muscle. These muscles are used in peristalsis.
—myenteric (my-en-te-rik) adj.

Back  -    New Search

myiasis (my--sis) n.

an infestation of a living organ or tissue by maggots. Treatment of external myiases involves the destruction and removal of maggots followed by the application of antibiotics to wounds and lesions.

Back  -    New Search

myo- prefix.

see MY-.

Back  -    New Search

myoblast (my-oh-blast) n.

a cell that develops into a muscle fibre.
—myoblastic adj.

Back  -    New Search

myocardial infarction (my-oh-kar-di-l) n.

death of a segment of heart muscle, which follows interruption of its blood supply (see CORONARY THROMBOSIS). The patient experiences sudden severe chest pain, which may spread to the arms and throat. The main danger is that of ventricular fibrillation, which accounts for most of the fatalities. Other complications include heart failure, rupture of the heart, phlebothrombosis, pulmonary embolism, pericarditis, shock, mitral incompetence, and perforation of the septum between the ventricles.

Back  -    New Search

myocarditis (my-oh-kar-dy-tis) n.

acute or chronic inflammation of the heart muscle. It may be seen alone or as part of endomyocarditis.

Back  -    New Search

myocardium (my-oh-kar-dim) n.

the middle of the three layers forming the wall of the heart (see also ENDOCARDIUM, EPICARDIUM). It is composed of cardiac muscle and forms the greater part of the heart wall.
—myocardial adj.

Back  -    New Search

myocele (my-oh-seel) n.

protrusion of a muscle through a rupture in its sheath.

Back  -    New Search

myoclonus (my-oh-kloh-ns) n.

a sudden spasm of the muscles. Myoclonus is a major feature of some progressive neurological illnesses with extensive degeneration of brain cells. nocturnal m. spasm of the muscles on falling asleep, which occurs in normal individuals.
—myoclonic (my-oh-klon-ik) adj.

Back  -    New Search

myocyte (my-oh-syt) n.

a muscle cell.

Back  -    New Search

myodynia (my-oh-din-i) n.

pain in the muscles.

Back  -    New Search

myofibrosis (my-oh-fy-broh-sis) n.

the replacement of muscle tissue by fibrous tissue, with consequent loss of muscle function.

Back  -    New Search

myogenic (my-oh-jen-ik) adj.

originating in muscle: applied to the inherent rhythmicity of contraction of some muscles (e.g. cardiac muscle), which does not depend on neural influences.

Back  -    New Search

myoglobin (my-oh-gloh-bin) n.

see MYOHAEMOGLOBIN.

Back  -    New Search

myoglobinuria (my-oh-gloh-bin-yoor-i) n.

see MYOHAEMOGLOBINURIA.

Back  -    New Search

myogram (my--gram) n.

a recording of the activity of a muscle. See ELECTROMYOGRAPHY.

Back  -    New Search

myograph (my--graf) n.

an instrument for recording the activity of muscular tissues. See ELECTROMYOGRAPHY.

Back  -    New Search

myohaemoglobin (myoglobin) (my-oh-hee-moh-gloh-bin) n.

an iron-containing protein, resembling haemoglobin, found in muscle cells. Like haemoglobin it contains a haem group, which binds reversibly with oxygen, and so acts as an oxygen reservoir within the muscle fibres.

Back  -    New Search

myohaemoglobinuria (myoglobinuria) (my-oh-hee-moh-gloh-bin-yoor-i) n.

the presence in the urine of the pigment myohaemoglobin.

Back  -    New Search

myokymia (my-oh-ky-mi) n.

prominent quivering of a few muscle fibres. It is a benign condition. See also FASCICULATION.

Back  -    New Search

myology (my-ol-ji) n.

the study of the structure, function, and diseases of the muscles.

Back  -    New Search

myoma (my-oh-m) n.

a benign tumour of muscle. It may originate in smooth muscle (see LEIOMYOMA) or in striated muscle.

Back  -    New Search

myomectomy (my-oh-mek-tmi) n.

an operation in which benign tumours (fibroids) are removed from the muscular wall of the uterus.

Back  -    New Search

myometritis (my-oh-mi-try-tis) n.

inflammation of the myometrium.

Back  -    New Search

myometrium (my-oh-mee-tri-m) n.

the muscular tissue of the uterus, which surrounds the endometrium. It is composed of smooth muscle that undergoes small regular spontaneous contractions.

Back  -    New Search

myoneural junction (my-oh-newr-l) n.

see NEUROMUSCULAR JUNCTION.

Back  -    New Search

myopathy (my-op--thi) n.

any disease of the muscles. The myopathies are usually subdivided into those that are inherited (see MUSCULAR DYSTROPHY) and those that are acquired. All are typified by weakness and wasting of the muscles, which may be associated with pain and tenderness.

Back  -    New Search

myopia (short-sightedness) (my-oh-pi) n.

the condition in which parallel light rays are brought to a focus in front of the retina. The condition is corrected by wearing spectacles with concave lenses and can now be treated surgically. Compare EMMETROPIA, HYPERMETROPIA.

—myopic (my-op-ik) adj.

Back  -    New Search

myoplasm (my-oh-plazm) n.

see SARCOPLASM.

Back  -    New Search

myoplasty (my-oh-plasti) n.

the plastic surgery of muscle, in which part of a muscle is used to repair tissue defects or deformities in the vicinity of the muscle.

Back  -    New Search

myosarcoma (my-oh-sar-koh-m) n.

a malignant tumour of muscle. See also LEIOMYOSARCOMA, RHABDOMYOSARCOMA.

Back  -    New Search

myosin (my-oh-sin) n.

the most abundant protein in muscle fibrils, having the important properties of elasticity and contractility. See STRIATED MUSCLE.

Back  -    New Search

myosis (my-oh-sis) n.

see MIOSIS.

Back  -    New Search

myositis (my-oh-sy-tis) n.

any of a group of muscle diseases in which inflammation and degenerative changes occur. Polymyositis is the most commonly occurring example. m. ossificans the formation of bone in a muscle that occurs after dislocations or fractures, especially around the elbow.

Back  -    New Search

myotactic (my-oh-tak-tik) adj.

relating to the sense of touch in muscles. m. reflex see STRETCH REFLEX.

Back  -    New Search

myotic (my-ot-ik) n.

see MIOTIC.

Back  -    New Search

myotomy (my-ot-mi) n.

the dissection or surgical division of a muscle.

Back  -    New Search

myotonia (my-oh-toh-ni) n.

a disorder of the muscle fibres that results in abnormally prolonged contractions. It is a feature of a hereditary condition starting in infancy or early childhood (m. congenita ) and of a form of muscular dystrophy (dystrophia myotonica).

Back  -    New Search

myotonic (my-oh-ton-ik) adj.

relating to muscle tone.

Back  -    New Search

myotonus (my-oh-toh-ns) n.

1 a tonic muscular spasm.

2 muscle tone.
Top

Back  -    New Search

myringa (mi-ring-) n.

the eardrum (see TYMPANIC MEMBRANE).

Back  -    New Search

myringitis (mi-rin-jy-tis) n.

inflammation of the eardrum. See OTITIS (MEDIA).

Back  -    New Search

myringoplasty (tympanoplasty) (mi-ring-oh-plasti) n.

surgical repair of a perforated eardrum by grafting.

Back  -    New Search

myringotome (mi-ring-oh-tohm) n.

a surgical knife used to pierce the eardrum in myringotomy.

Back  -    New Search

myringotomy (mi-ring-ot-mi) n.

incision of the eardrum to create an artificial opening, either to allow infected fluid to drain from the middle ear in acute otitis media or to remove fluid in glue ear and permit the insertion of a grommet.

Back  -    New Search

myx- (myxo-) prefix

denoting mucus.

Back  -    New Search

myxoedema (miks-i-dee-m) n.

1 a dry firm waxy swelling of the skin and subcutaneous tissues found in patients with underactive thyroid glands (see HYPOTHYROIDISM).

2 the clinical syndrome due to hypothyroidism in adult life, including coarsening of the skin, intolerance to cold, weight gain, and mental dullness.
Top

—myxoedematous adj.

Back  -    New Search

myxofibroma (miks-oh-fy-broh-m) n.

a benign tumour of fibrous tissue that contains myxomatous elements or has undergone mucoid degeneration.

Back  -    New Search

myxoid cyst (miks-oid) n.

a small cyst containing a thick sticky fluid. It develops over the end joint of a finger or toe and should not be cut out, because the cyst is usually in communication with the underlying joint.

Back  -    New Search

myxoma (miks-oh-m) n.

a benign gelatinous tumour of connective tissue. atrial m. a tumour of the heart, usually of the left side, arising from the septum dividing the two upper chambers. Symptoms may include fever, lassitude, joint pains, and sudden loss of consciousness.
—myxomatous adj.

Back  -    New Search

myxosarcoma (miks-oh-sar-koh-m) n.

a sarcoma containing mucoid material.

Back  -    New Search

myxovirus (miks-oh-vy-rs) n.

one of a group of RNA-containing viruses that are associated with various diseases in animals and humans. The orthomyxoviruses cause diseases of the respiratory tract, most notably influenza. The related paramyxoviruses include the respiratory syncytial virus (RSV) and the agents causing measles, mumps, and para-influenza.

Back  -    New Search

N

N

symbol for nitrogen or newton.

Back  -    New Search

Na

symbol for sodium.

Back  -    New Search

nabilone (nab-i-lohn) n.

a drug related to cannabis, administered by mouth to control severe nausea and vomiting, especially when caused by anticancer drugs. Trade name: Cesamet .

Back  -    New Search

nabothian follicle (nabothian cyst, nabothian gland) (n-boh-thi-n) n.

one of a number of cysts on the cervix of the uterus. The sacs, which contain mucus, form when the ducts of the glands in the cervix are blocked by a new growth of epithelium over an area damaged because of infection. [M. Naboth (1675–1721), German anatomist]

Back  -    New Search

nadolol (nad--lol) n.

a beta blocker administered by mouth for the treatment of angina pectoris and high blood pressure (hypertension). Trade name: Corgard .

Back  -    New Search

Naegele rule (nay-gi-li) n.

a method used to estimate the probable date of the onset of labour: nine months and seven days are added to the date of the first day of the last menstrual period. A correction is required if the woman does not have 28-day menstrual cycles. [F. K. Naegele (1777–1851), German obstetrician]

Back  -    New Search

Naegele's obliquity n.

see ASYNCLITISM.

Back  -    New Search

naevus (nee-vs) n. (pl. naevi)

a birthmark: a clearly defined malformation of the skin, present at birth. capillary n. (port-wine stain ) a permanent purplish discoloration, composed of small blood vessels, that may occur anywhere but usually appears on the upper half of the body. Laser treatment can reduce the discoloration. Occasionally it may be associated with a malformation of blood vessels over the brain, for example in the Sturge-Weber syndrome. strawberry n. (strawberry mark ) a raised red lump, composed of small blood vessels, usually appearing on the face and growing rapidly in the first month of life. It slowly resolves and spontaneously disappears between the ages of five and ten. See also MOLE^2.

Back  -    New Search

Naga sore (nah-g) n.

see TROPICAL ULCER.

Back  -    New Search

NAI n.

see NONACCIDENTAL INJURY.

Back  -    New Search

nail (nayl) n.

a horny structure, composed of keratin, formed from the epidermis on the dorsal surface of each finger and toe. Growth of the nail occurs at the end of the nail root, behind the exposed nail, by division of the germinative layer of the underlying epidermis. Anatomical name: unguis .

Back  -    New Search

nalidixic acid (nal-i-diks-ik) n.

a quinolone antibiotic active against various bacteria and administered by mouth to treat infections of the urinary and digestive systems. Trade names: Negram , Uriben .

Back  -    New Search

naloxone (nal-oks-ohn) n.

a drug that is a specific antidote to morphine and similar narcotic drugs. It is administered by intravenous or subcutaneous injection. As it is short-acting, repeated doses may be necessary. Trade name: Narcan .

Back  -    New Search

naltrexone (nal-treks-ohn) n.

a narcotic antagonist drug used in the maintenance treatment of heroin- and other opiate dependent patients. It is administered by mouth. Trade name: Nalorex .

Back  -    New Search

nandrolone (nan-droh-lohn) n.

a synthetic male sex hormone with anabolic effects. It is administered by injection. Trade name: Deca-Durabolin .

Back  -    New Search

nano- prefix

denoting
1 extremely small size.
2 one thousand-millionth part (10-9).

Back  -    New Search

nanometre (nan-oh-mee-ter) n.

one thousand-millionth of a metre (10-9 m). One nanometre is equal to 10 angstrom. Symbol: nm.

Back  -    New Search

nanophthalmos (nan-off-thal-ms) n.

a congenitally small eye in which all the structures are proportionally reduced.

Back  -    New Search

nape (nayp) n.

see NUCHA.

Back  -    New Search

naphazoline (naf-az-oh-leen) n.

a drug that constricts small blood vessels and is administered as nasal drops to relieve congestion in rhinitis and sinusitis. Trade name: Vasocon-A .

Back  -    New Search

napkin rash (nappy rash) (nap-kin) n.

a red skin rash within the napkin area, usually caused by chemical irritation (ammoniacal dermatitis) or fungal infection with Candida. Ammoniacal dermatitis is caused by skin contact with wet soiled nappies; treatment involves exposure to air, application of barrier creams, and frequent nappy changes. Candidal nappy rash is treated with antifungal creams. Other causes of napkin rash include eczema and psoriasis.

Back  -    New Search

naproxen (n-proks-n) n.

an analgesic drug that also reduces inflammation and fever (see NSAID). It is administered by mouth to treat rheumatoid arthritis, ankylosing spondylitis, and gout. Trade names: Naprosyn , Nycopren .

Back  -    New Search

narcissism (nar-sis-izm) n.

an excessive involvement with oneself and one's self-importance. In Freudian terms it is a state in which the ego has taken itself as a love object. An extreme degree of narcissism may be a symptom of schizophrenia or personality disorder.
—narcissistic adj.

Back  -    New Search

narco- prefix

denoting narcosis; stupor.

Back  -    New Search

narcoanalysis (nar-koh--nal-i-sis) n.

a type of psychotherapy during which the patient is in a relaxed or sleeplike state induced by drugs.

Back  -    New Search

narcolepsy (nar-k-lep-si) n.

an extreme tendency to fall asleep in quiet surroundings or when engaged in monotonous activities. The patient can be woken easily and is immediately alert. It is often associated with cataplexy.
—narcoleptic adj., n.

Back  -    New Search

narcosis (nar-koh-sis) n.

a state of diminished consciousness or complete unconsciousness caused by the use of narcotic drugs. The body's normal reactions to stimuli are diminished and the body may become sedated or completely anaesthetized.

Back  -    New Search

narcotic (nar-kot-ik) n.

a drug that relieves pain and also induces stupor and insensibility. The term is used particularly for morphine and other derivatives of opium (see OPIATE) but is also applied to other drugs that depress brain function (e.g. general anaesthetics and hypnotics).

Back  -    New Search

nares (nair-eez) pl. n. (sing. naris)

openings of the nose. external (or anterior ) n. the nostrils, which lead from the nasal cavity to the outside. internal (or posterior ) n. (choanae ) the openings leading from the nasal cavity into the pharynx.

Back  -    New Search

nasal (nay-zl) adj.

relating to the nose. n. bone either of a pair of narrow oblong bones that together form the bridge and root of the nose. n. cavity the space inside the nose that lies between the floor of the cranium and the roof of the mouth. n. concha (turbinate bone ) any of three thin scroll-like bones that form the sides of the nasal cavity.

Back  -    New Search

naso- prefix

denoting the nose.

Back  -    New Search

nasogastric (nay-zoh-gas-trik) adj.

relating to the nose and stomach. n. tube a tube inserted into the stomach through the nose (see INTUBATION).

Back  -    New Search

nasolacrimal (nay-zoh-lak-ri-ml) adj.

relating to the nose and the lacrimal (tear-producing) apparatus. n. duct the duct that drains the tears away from the lacrimal apparatus into the inferior meatus of the nose.

Back  -    New Search

nasopharynx (rhinopharynx) (nay-zoh-fa-rinks) n.

the part of the pharynx that lies above the soft palate.
—nasopharyngeal (nay-zoh-f-rin-ji-l) adj.

Back  -    New Search

nates (nay-teez) pl. n.

the buttocks.
—natal (nay-t'l) adj.

Back  -    New Search

National Council for Vocational Qualifications (nash-n-l) n.

see NCVQ.

Back  -    New Search

National Health Service n.

(in the UK) a comprehensive service offering therapeutic and preventive medical and surgical care, including the prescription and dispensing of medicines, spectacles, and medical and dental appliances. Exchequer funds pay for the services of doctors, nurses, and other professionals, as well as residential costs in NHS hospitals, and meet a substantial part of the cost of the medicines and appliances.

Back  -    New Search

natriuretic (nay-tri-yoor-et-ik) n.

an agent that promotes the excretion of sodium salts in the urine. Most diuretics are natriuretics.

Back  -    New Search

natural childbirth (nach-r-l) n.

labour and delivery that relies largely on the efforts of the mother alone, with the minimum of medical intervention.

Back  -    New Search

natural killer cell n.

a type of lymphocyte that can kill virus-infected cells and certain cancer cells but does not require the antigen-presenting mechanisms needed by killer cells (cytotoxic T-cells).

Back  -    New Search

naturopathy (nay-cher-op--thi) n.

a system of medicine that relies upon the use of only ‘natural’ substances for the treatment of disease, rather than drugs.

Back  -    New Search

nausea (naw-zi) n.

the feeling that one is about to vomit, as experienced in seasickness. Actual vomiting often occurs subsequently.

Back  -    New Search

navel (nay-vl) n.

see umbilicus.

Back  -    New Search

navicular bone (n-vik-yoo-ler) n.

a boatshaped bone of the ankle (see TARSUS) that articulates with the three cuneiform bones in front and with the talus behind.

Back  -    New Search

NCVQ n.

(in the UK) National Council for Vocational Qualifications: a body set up by the government to achieve a coherent national framework for vocational qualifications in England, Wales, and Northern Ireland. Five levels of National Vocational Qualification (NVQ) are currently accredited by the council.

Back  -    New Search

NDU n.

(in the UK) Nursing Development Unit: a centre for creative nursing managed directly by nurses, who are responsible for controlling the budget and appointing staff. The unit can be based in hospital or the community in either the public or the private sector. NDUs are committed to practising research-based patient-centred care.

Back  -    New Search

nearthrosis (nee-arth-roh-sis) n.

see PSEUDARTHROSIS.

Back  -    New Search

nebula (neb-yoo-l) n.

a faint opacity of the cornea that remains after an ulcer has healed.

Back  -    New Search

nebulizer (neb-yoo-ly-zer) n.

an instrument used for applying a liquid in the form of a fine spray.

Back  -    New Search

NEC n.

see NECROTIZING ENTEROCOLITIS.

Back  -    New Search

Necator (ni-kay-ter) n.

a genus of parasitic nematodes that live in the small intestine (see HOOKWORM). N. americanus the species that infests man.

Back  -    New Search

necatoriasis (ni-kay-ter-I--sis) n.

an infestation of the small intestine by the parasitic hookworm Necator americanus. See HOOKWORM (DISEASE).

Back  -    New Search

neck (nek) n.

1 a narrowed region of the body connecting the head to the trunk. It contains the cervical vertebrae.

2 any other constricted region of an organ or part, such as the narrow section of the femur between the head and shaft. See CERVIX.
Top

Back  -    New Search

necro- prefix

denoting death or dissolution.

Back  -    New Search

necrobiosis (nek-roh-by-oh-sis) n.

a gradual process by which cells lose their function and die.

Back  -    New Search

necrology (nek-rol-ji) n.

the study of the phenomena of death, involving determination of the moment of death and the different changes that occur in the tissues of the body after death.

Back  -    New Search

necrophilism (necrophilia) (nek-rof-il-izm) n.

sexual attraction to corpses. See also SEXUAL DEVIATION.
—necrophile (nek-roh-fyl) n.

Back  -    New Search

necropsy (nek-rop-si) n.

see AUTOPSY.

Back  -    New Search

necrosis (mortification) (nek-roh-sis) n.

the death of some or all of the cells in an organ or tissue, caused by disease, physical or chemical injury, or interference with the blood supply (see GANGRENE).
—necrotic adj.

Back  -    New Search

necrospermia (nek-roh-sper-mi) n.

the presence of either dead or motionless spermatozoa in the semen. See INFERTILITY.

Back  -    New Search

necrotizing enterocolitis (NEC) (nek-r-tyz-ing) n.

a serious disease affecting the bowel during the first three weeks of life; it is much more common in preterm babies. The abdomen distends and blood and mucus appear in the stools; the bowel may perforate.

Back  -    New Search

necrotizing fasciitis n.

bacterial infection of the layer of fascia beneath the skin by Streptococcus Type A. There is tissue necrosis and toxin production causing shock and organ failure. The elderly and those who have recently undergone surgery are particularly vulnerable to the infection, which requires prompt treatment with antibiotics and excision of the involved tissue.

Back  -    New Search

nedocromil (ned-oh-kroh-mil) n.

an anti-inflammatory drug used to treat bronchitis and bronchial asthma. It is administered by metered-dose aerosol inhaler. Trade name: Tilade .

Back  -    New Search

needle (nee-d'l) n.

a slender sharp-pointed instrument. Needles used for sewing up tissue during surgery are equipped with an eye for threading suture material or have the suture material fused onto them. Hollow needles are used to inject substances into the body, to obtain specimens of tissue (see PUNCTURE), or to withdraw fluid from a cavity. See also STOP NEEDLE.

Back  -    New Search

needle-stick injury n.

a common accidental injury to the fingers and hands of nurses and doctors by contaminated injection needles. It can result in transmitted infections (e.g. hepatitis, AIDS).

Back  -    New Search

needling (need-ling) n.

a form of capsulotomy in which a sharp needle is used to make a hole in the capsule surrounding the lens of the eye. This technique has now largely been replaced by use of the YAG laser.

Back  -    New Search

needs deprivation n.

an unhealthy state said to exist if an individual is unable to meet basic human needs.

Back  -    New Search

negativism (neg--tiv-izm) n.

uncooperative or obstructive behaviour. active n. negativism in which the individual does the opposite of what he is asked. This is usually associated with other features of catatonia. passive n. negativism in which the person fails to cooperate, occurring in schizophrenia and depression.

Back  -    New Search

Neisseria (ny-seer-i) n.

a genus of spherical Gram-negative aerobic nonmotile bacteria characteristically grouped in pairs. N. gonorrhoeae (the gonococcus ) the species that causes gonorrhoea, found within pus cells of urethral and vaginal discharge. N. meningitidis (the meningococcus ) the species that causes meningococcal meningitis. Meningococci are found within pus cells of infected cerebrospinal fluid and blood or in the nasal passages of carriers.

Back  -    New Search

nematode (roundworm) (nem--tohd) n.

any one of a large group of worms having an unsegmented cylindrical body, tapering at both ends. Some nematodes, including hookworms, filariae, pinworms, and guinea worms, are parasites of man.

Back  -    New Search

neo- prefix

denoting new or newly formed.

Back  -    New Search

neoadjuvant chemotherapy (nee-oh-aj-oo-vnt) n.

chemotherapy given before treatment of a primary tumour with the aim of improving the results of surgery or radiotherapy and preventing the development of metastases. Compare ADJUVANT THERAPY.

Back  -    New Search

neocerebellum (nee-oh-se-ri-bel-m) n.

the middle lobe of the cerebellum, excluding the pyramid and uvula.

Back  -    New Search

neologism (ni-ol--jizm) n.

(in psychiatry) the invention of words to which meanings are attached. It may be a symptom of a psychotic illness, such as schizophrenia.

Back  -    New Search

neomycin (nee-oh-my-sin) n.

an aminoglycoside antibiotic used to treat infections caused by a wide range of bacteria, mainly those affecting the skin and eyes. It is usually applied in creams or drops with other antibiotics, but can also be given by mouth.

Back  -    New Search

neonatal mortality rate (nee-oh-nay-t'l) n.

see INFANT (MORTALITY RATE).

Back  -    New Search

neonatal screening n.

screening tests carried out on newborn babies to detect diseases that appear in the neonatal period, such as phenylketonuria (see GUTHRIE TEST). Early detection enables treatment to be instigated before irreversible damage occurs to the baby.

Back  -    New Search

neonate (nee-oh-nayt) n.

an infant at any time during the first four weeks of life. The word is particularly applied to infants just born or in the first week of life.
—neonatal adj.

Back  -    New Search

neoplasm (nee-oh-plazm) n.

any new and abnormal growth: a benign or malignant tumour.

Back  -    New Search

neosphincter (nee-oh-sfink-ter) n.

a substituted muscle or an implant for an absent or ineffective sphincter (see ARTIFICIAL SPHINCTER).

Back  -    New Search

neostigmine (nee-oh-stig-meen) n.

a parasympathomimetic drug that acts by inhibiting the enzyme cholinesterase. It is used to diagnose and treat myasthenia gravis, as an antidote to some muscle-relaxant drugs, and to treat some intestinal disorders and glaucoma. Neostigmine is administered by mouth, injection, or in eye-drops. Trade name: Prostigmin .

Back  -    New Search

neovascularization (nee-oh-vas-kew-ler-l-zay-shn) n.

the abnormal formation of new and fragile blood vessels, usually in response to ischaemia. choroidal n. the growth of abnormal vessels, derived from the choroid, to form a choroidal neovascular membrane in the space below the retinal pigment epithelium (see RETINA). This occurs, for example, in macular degeneration and diabetic retinopathy.

Back  -    New Search

nephr- (nephro-) prefix

denoting the kidney(s).

Back  -    New Search

nephralgia (ni-fral-ji) n.

pain in the kidney, which is felt in the loin and can be caused by a variety of kidney complaints.

Back  -    New Search

nephrectomy (ni-frek-tmi) n.

surgical removal of a kidney. radical n. removal of the entire organ together with its surrounding fat and the adjacent adrenal gland, performed for cancer of the kidney.

Back  -    New Search

nephritis (Bright's disease) (ni-fry-tis) n.

inflammation of the kidney. Nephritis is a nonspecific term used to describe a condition resulting from a variety of causes. See GLOMERULONEPHRITIS.

Back  -    New Search

nephroblastoma (Wilms' tumour) (nef-roh-blas-toh-m) n.

a malignant tumour arising from the embryonic kidney and found in young children (usually between the ages of three and eight). In some cases it is associated with a chromosome abnormality, when aniridia and other abnormal features are present. Treatment is by nephrectomy followed by chemotherapy.

Back  -    New Search

nephrocalcinosis (nef-roh-kal-sin-oh-sis) n.

the presence of calcium deposits in the kidneys. This can be caused by excess calcium in the blood, due to overactivity of the parathyroid glands, or it may result from an underlying abnormality of the kidney.

Back  -    New Search

nephrocapsulectomy (nef-roh-kaps-yoo-lek-tmi) n.

surgical removal of the fibrous capsule around a kidney.

Back  -    New Search

nephrolithiasis (nef-roh-lith-I--sis) n.

the presence of stones in the kidney (see CALCULUS). Such stones can cause pain and blood in the urine, but they may produce no symptoms.

Back  -    New Search

nephrolithotomy (nef-roh-lith-ot-mi) n.

the surgical removal of a stone from the kidney by an incision into the kidney substance. percutaneous n. nephrolithotomy that is performed via a nephroscope passed into the kidney through a tract from the skin surface.

Back  -    New Search

nephrology (ni-frol-ji) n.

the branch of medicine concerned with the study, investigation, and management of diseases of the kidney. See also UROLOGY.
—nephrologist n.

Back  -    New Search

nephroma (ni-froh-m) n.

a tumour of the kidney.

Back  -    New Search

nephron (nef-ron) n.

the active unit of excretion in the kidney (see illustration). Blood is filtered through the glomerulus into the Bowman's capsule so that water, nitrogenous waste, and many other substances pass into the renal tubule. Here most of the substances are reabsorbed back into the blood, the remaining fluid (urine) passing into the collecting duct, which drains into the ureter.

Back  -    New Search

nephropathy (ni-frop--thi) n.

disease of the kidney.

Back  -    New Search

nephropexy (nef-roh-peks-i) n.

an operation to fix a mobile kidney. The kidney is fixed to the twelfth rib and adjacent posterior abdominal wall.

Back  -    New Search

nephroptosis (nef-rop-toh-sis) n.

abnormal descent of a kidney into the pelvis on standing. If this is accompanied by pain and obstruction to free drainage of urine by the kidney, nephropexy may be advised.

Back  -    New Search

nephrosclerosis (nef-roh-skleer-oh-sis) n.

hardening of the arteries and arterioles of the kidneys.

Back  -    New Search

nephroscope (nef-roh-skohp) n.

an instrument (see ENDOSCOPE) that is used for examining the interior of the kidney (nephroscopy ). It is usually passed into the renal pelvis through a track from the skin surface after needle nephrostomy and dilatation of the tract over a guide wire. The nephroscope allows the passage of instruments under direct vision to remove calculi (see NEPHROLITHOTOMY) or disintegrate them by ultrasound probes or electrohydraulic shock waves (see LITHOTRIPSY).

Back  -    New Search

nephrosis (ni-froh-sis) n.

(in pathology) degenerative changes in the epithelium of the kidney tubules. The term is sometimes used loosely for the nephrotic syndrome.

Back  -    New Search

nephrostomy (ni-frost-mi) n.

drainage of urine from the kidney by a tube (catheter) passing through the kidney via the skin surface. This is commonly used as a temporary procedure after operations on the kidney.

Back  -    New Search

nephrotic syndrome (ni-frot-ik) n.

a condition in which there is great loss of protein in the urine, reduced levels of albumin in the blood, and generalized oedema. It can be caused by a variety of disorders, most usually glomerulonephritis.

Back  -    New Search

nephrotomy (ni-frot-mi) n.

surgical incision into the substance of the kidney. This is usually undertaken to remove a kidney stone (see NEPHROLITHOTOMY).

Back  -    New Search

nephroureterectomy (ureteronephrectomy) (nef-roh-yoor-i-ter-ek-tmi) n.

surgical removal of a kidney together with its ureter. This operation is performed for cancer of the kidney pelvis or ureter.

Back  -    New Search

nerve (nerv) n.

a bundle of nerve fibres enclosed in a connective tissue sheath (see illustration). motor n. a nerve that transmits impulses from the brain or spinal cord to the muscles and glands. sensory n. a nerve that transmits impulses inwards from the sense organs to the brain and spinal cord.

Back  -    New Search

nerve block n.

a method of producing anaesthesia in part of the body by blocking the passage of pain impulses in the sensory nerves supplying it. A local anaesthetic, such as lignocaine, is injected into the tissues in the region to be anaesthetized. See also RING BLOCK.

Back  -    New Search

nerve cell n.

see NEURONE.

Back  -    New Search

nerve ending n.

the final part (terminal) of one of the branches of a nerve fibre, where a neurone makes contact either with another neurone or with a muscle or gland cell.

Back  -    New Search

nerve entrapment syndrome (in-trap-mnt) n.

any syndrome resulting from pressure on a nerve from surrounding structures. Examples include the carpal tunnel syndrome and meralgia paraesthetica.

Back  -    New Search

nerve fibre n.

the long fine process that extends from the cell body of a neurone and carries nerve impulses. Bundles of nerve fibres running together form a nerve.

Back  -    New Search

nerve gas n.

any gas that disrupts the normal functioning of nerves and thus of the muscles they supply.

Back  -    New Search

nerve impulse n.

the electrical activity in the membrane of a neurone that is the means by which information is transmitted within the nervous system along the axons of the neurones.

Back  -    New Search

nerve regeneration n.

the growth of new nerve tissue, which occurs at a very slow rate (1–2 mm per day) after a nerve has been severed and is often partially or totally incomplete. See also AXONOTMESIS, NEUROTMESIS.

Back  -    New Search

nervous breakdown (ner-vs brayk-down) n.

a lay term applied to a range of emotional crises varying from a brief attack of ‘hysterical’ behaviour to a major psychoneurotic illness with severe long-term effects on the life of the sufferer. The term is also sometimes used as a euphemism for a frank psychiatric illness, such as schizophrenia.

Back  -    New Search

nervous system n.

the vast network of cells specialized to carry information (in the form of nerve impulses) to and from all parts of the body in order to bring about bodily activity. See AUTONOMIC NERVOUS SYSTEM, CENTRAL NERVOUS SYSTEM, PERIPHERAL NERVOUS SYSTEM.

Back  -    New Search

Nesbit's operation (nez-bits) n.

an operation originally devised to surgically straighten a congenitally curved penis but now more frequently employed to correct the penile curvature caused by Peyronie's disease. [R. M. Nesbit (20th century), US surgeon]

Back  -    New Search

nettle rash (ne-t'l) n.

see URTICARIA.

Back  -    New Search

Neumann's model (new-mnz) n.

a model for nursing in which the patient's perception of stress-producing factors (stressors) and his or her reaction and adjustment to these are examined in relation to physiological, sociological, cultural, developmental and spiritual factors. See also NURSING MODELS. [B. Neumann (1924– ), US nurse theorist]

Back  -    New Search

neur- (neuro-) prefix

denoting nerves or the nervous system.

Back  -    New Search

neural (newr-l) adj.

relating to a nerve or nerves. n. arch see VERTEBRA.

Back  -    New Search

neuralgia (newr-al-j) n.

a severe burning or stabbing pain often following the course of a nerve. postherpetic n. intense debilitating pain felt at the site of a previous attack of shingles. trigeminal n. (tic douloureux ) neuralgia in which brief paroxysms of searing pain are felt in the distribution of one or more branches of the trigeminal nerve in the face.

Back  -    New Search

neural tube n.

a hollow tube of tissue in the embryo from which the brain and spinal cord develop. It is formed when two edges of a groove in a plate of primitive neural tissue (neural plate ) come together and fuse.

Back  -    New Search

neural tube defects pl. n.

a group of congenital abnormalities involving defects in the spine or skull caused by failure of the neural tube to form normally. They include spina bifida, in which the bony arches of the spine fail to close, and more severe defects of bone fusion involving herniation of neural tissue and consequent mental and physical disorders, such as meningocele, meningomyelocele, and meningoencephalocele.

Back  -    New Search

neurapraxia (newr--praks-i) n.

temporary loss of nerve function resulting in tingling, numbness, and weakness. It is usually caused by compression of the nerve.

Back  -    New Search

neurasthenia (newr-s-th'ee-ni) n.

a set of psychological and physical symptoms, including fatigue, irritability, headache, and dizziness. It can be caused by organic damage, such as a head injury, or it can be due to neurosis.
—neurasthenic adj., n.

Back  -    New Search

neurectasis (newr-ek-t-sis) n.

the surgical procedure for stretching a peripheral nerve.

Back  -    New Search

neurectomy (newr-ek-tmi) n.

the surgical removal of the whole or part of a nerve.

Back  -    New Search

neurilemma (neurolemma) (newr-i-lem-) n.

the sheath of the axon of a nerve fibre. The neurilemma of a medullated fibre contains myelin.
—neurilemmal adj.

Back  -    New Search

neurilemmoma (neurinoma) (newr-i-lem-oh-m) n.

a benign slow-growing tumour that arises from the neurilemma of a nerve fibre.

Back  -    New Search

neurinoma (newr-i-noh-m) n.

see NEURILEMMOMA.

Back  -    New Search

neuritis (newr-I-tis) n.

a disease of the peripheral nerves showing the pathological changes of inflammation. The term is also used in a less precise sense as an alternative to neuropathy. See also RETROBULBAR NEURITIS.

Back  -    New Search

neuroanatomy (newr-oh--nat-mi) n.

the study of the structure of the nervous system.

Back  -    New Search

neuroblast (newr-oh-blast) n.

any of the nerve cells of the embryo that give rise to neurones.

Back  -    New Search

neuroblastoma (newr-oh-blas-toh-m) n.

a malignant tumour composed of embryonic nerve cells. It may originate in any part of the sympathetic nervous system, most commonly in the medulla of the adrenal gland.

Back  -    New Search

neurocranium (newr-oh-kray-nim) n.

the part of the skull that encloses the brain.

Back  -    New Search

neurodermatitis (newr-oh-der-m-ty-tis) n.

see LICHEN (SIMPLEX CHRONICUS).

Back  -    New Search

neuroendocrine system (newr-oh-end--kryn) n.

the system of dual control of certain activities of the body by means of both nerves and circulating hormones. It can give rise to neuroendocrine tumours , which secrete active hormones. See NEUROHORMONE, NEUROSECRETION.

Back  -    New Search

neuroepithelioma (newr-oh-epi-th'ee-li-oh-m) n.

a malignant tumour of the retina of the eye. It is a form of glioma and may spread into the brain if not treated early.

Back  -    New Search

neuroepithelium (newr-oh-epi-th'ee-lim) n.

a type of epithelium associated with organs of special sense. It contains sensory nerve endings and is found in the retina, the membranous labyrinth, and the taste buds.
—neuroepithelial adj.

Back  -    New Search

neurofibroma (Schwannoma) (newr-oh-fy-broh-m) n.

a benign tumour growing from the fibrous coverings of a peripheral nerve.

Back  -    New Search

neurofibromatosis (von Recklinghausen's disease) (newr-oh-fy-broh-m-toh-sis) n.

a congenital disease, typified by numerous neurofibromas. Tumours may occur in the spinal canal, where they may press on the spinal cord. The tumours sometimes (but rarely) become malignant, giving rise to neurofibrosarcomas .

Back  -    New Search

neurogenesis (newr-oh-jen-i-sis) n.

the growth and development of nerve cells.

Back  -    New Search

neurogenic (newr-oh-jen-ik) adj.

1 caused by disease or dysfunction of the nervous system.

2 arising in nervous tissue.
Top

3 caused by nerve stimulation.
Top

Back  -    New Search

neuroglia (newr-og-li) n.

see GLIA.

Back  -    New Search

neurohormone (newr-oh-hor-mohn) n.

a hormone, such as vasopressin or noradrenaline, that is produced within specialized nerve cells and is secreted from the nerve endings into the circulation.

Back  -    New Search

neurohypophysis (newr-oh-hy-pof-i-sis) n.

see PITUITARY GLAND.

Back  -    New Search

neurolemma (newr-oh-lem-) n.

see NEURILEMMA.

Back  -    New Search

neuroleptic (newr-oh-lep-tik) n.

any drug that induces an altered state of consciousness, such as a major tranquillizer.

Back  -    New Search

neurology (newr-ol-ji) n.

the study of the structure, functioning, and diseases of the nervous system (including the brain, spinal cord, and all the peripheral nerves).
—neurological adj. —neurologist n.

Back  -    New Search

neuroma (newr-oh-m) n.

any tumour derived from cells of the nervous system, now usually categorized more specifically (e.g. neurofibroma, neurilemmoma). acoustic n. a slow-growing benign tumour of the sheath of the vestibular nerve. It progresses to cause tinnitus and hearing loss.

Back  -    New Search

neuromuscular junction (myoneural junction) (newr-oh-mus-kew-ler) n.

the meeting point of a motor nerve fibre and the muscle fibre that it supplies. It consists of a minute gap across which a neurotransmitter must diffuse from the nerve to trigger contraction of the muscle.

Back  -    New Search

neuromyelitis optica (Devic's disease) (newr-oh-my--ly-tis op-tik-) n.

a condition that is closely related to multiple sclerosis. Typically there is a transverse myelitis, producing paralysis and numbness of the limbs and trunk below the inflamed spinal cord, and retrobulbar (optic) neuritis affecting both optic nerves.

Back  -    New Search

neurone (nerve cell) (newr-ohn) n.

one of the basic functional units of the nervous system: a cell specialized to transmit electrical nerve impulses and so carry information from one part of the body to another (see illustration). Impulses enter the neurone through branches of the dendrites and are carried away from the cell body through the axon (nerve fibre). They are transmitted to adjacent neurones or to effector organs through minute gaps (see SYNAPSE, NEUROMUSCULAR JUNCTION). See also MOTOR NEURONE.

Back  -    New Search

neuropathy (newr-op--thi) n.

any disease of the peripheral nerves, usually causing weakness and numbness.
—neuropathic (newr-oh-path-ik) adj.

Back  -    New Search

neuropathic bladder n.

a malfunctioning bladder due to partial or complete interruption of its nerve supply. Causes include injury to the spinal cord, spina bifida, multiple sclerosis, and diabetic neuropathy.

Back  -    New Search

neurophysiology (newr-oh-fiz-i-ol-ji) n.

the study of the complex chemical and physical changes that are associated with the activity of the nervous system.

Back  -    New Search

neuroplasty (newr-oh-plasti) n.

reconstructive surgery for damaged or severed peripheral nerves.

Back  -    New Search

neuropsychiatry (newr-oh-si-ky--tri) n.

the branch of medicine concerned with the psychiatric effects of disorders of neurological function or structure. It investigates the relationship between demonstrable brain changes and the resulting effects on the mind.

Back  -    New Search

neurorrhaphy (newr-o-rfi) n.

the operation of suturing a cut nerve.

Back  -    New Search

neurosecretion (newr-oh-si-kree-shn) n.

any substance produced within, and secreted by, a nerve cell. Important examples are the hormone-releasing factors produced by the cells of the hypothalamus.

Back  -    New Search

neurosis (newr-oh-sis) n. (pl. neuroses)

any long-term mental or behavioural disorder in which contact with reality is retained and the condition is recognized by the sufferer as abnormal. A neurosis essentially features anxiety or behaviour exaggeratedly designed to avoid anxiety. Defence mechanisms against anxiety take various forms and may appear as phobias, obsessions, compulsions, or sexual dysfunctions. Behaviour therapy seems effective in some cases. In accordance with a recent classification, the disorders formerly included under the neuroses have been renamed anxiety disorders. See also ANXIETY, CONVERSION DISORDER, DEPRESSION, DISSOCIATIVE DISORDER, OBSESSION.
—neurotic adj.

Back  -    New Search

neurosurgery (newr-oh-ser-jer-i) n.

the surgical or operative treatment of diseases of the brain and spinal cord.

Back  -    New Search

neurosyphilis (newr-oh-sif-i-lis) n.

syphilis affecting the nervous system.

Back  -    New Search

neurotmesis (newr-ot-mee-sis) n.

an injury in which a nerve is severed. Nerve regeneration is slow.

Back  -    New Search

neurotomy (newr-ot-mi) n.

the surgical procedure of severing a nerve.

Back  -    New Search

neurotoxic (newr-oh-toks-ik) adj.

poisonous or harmful to nerve cells.

Back  -    New Search

neurotransmitter (newr-oh-tranz-mit-er) n.

a chemical substance, such as acetylcholine, noradrenaline, dopamine, or serotonin, that is released from nerve endings to transmit impulses across synapses to other nerves and across the minute gaps between the nerves and the muscles or glands that they supply.

Back  -    New Search

neurotripsy (newr-oh-trip-si) n.

crushing or bruising of a nerve.

Back  -    New Search

neurotrophic (newr-oh-trof-ik) adj.

relating to the growth and nutrition of neural tissue in the body.

Back  -    New Search

neurotropic (newr-oh-trop-ik) adj.

growing towards or having an affinity for neural tissue. The term may be applied to viruses, chemicals, or toxins.

Back  -    New Search

neutropenia (new-troh-pee-ni) n.

a decrease in the number of neutrophils in the blood. Neutropenia may occur in a wide variety of diseases, including aplastic anaemias, agranulocytosis, and acute leukaemias. It results in an increased susceptibility to infections.

Back  -    New Search

neutrophil (polymorph) (new-tr-fil) n.

a variety of granulocyte distinguished by the presence in its cytoplasm of fine granules that stain purple with Romanowsky stains. It is capable of ingesting and killing bacteria and provides an important defence against infection.

Back  -    New Search

newton (new-t'n) n.

the SI unit of force, equal to the force required to impart to 1 kilogram an acceleration of 1 metre per second per second. Symbol: N.

Back  -    New Search

nexus (neks-s) n.

(in anatomy) a connection or link.

Back  -    New Search

NHSTA n.

(in the UK) National Health Service Training Authority: a statutory body established in 1983 to identify training needs, formulate, coordinate, and develop national policies and standards, and provide and arrange for the provision of training programmes, courses, and research to cover all health professionals working in the NHS.

Back  -    New Search

niacin (ny--sin) n.

see NICOTINIC ACID.

Back  -    New Search

nicardipine (ni-kar-di-peen) n.

a calcium antagonist used to treat long-term angina. It is administered by mouth. Trade name: Cardene .

Back  -    New Search

niclosamide (ni-kloh-s-myd) n.

an anthelmintic drug used to remove tapeworms. It is administered by mouth and is relatively free of side effects. Trade name: Yomesan .

Back  -    New Search

nicotinamide (nik--tin--myd) n.

a B vitamin: the amide of nicotinic acid.

Back  -    New Search

nicotine (nik--teen) n.

a poisonous alkaloid derived from tobacco, responsible for the dependence of regular smokers on cigarettes. In small doses nicotine has a stimulating effect on the autonomic nervous system. Large doses cause paralysis of the autonomic ganglia.

Back  -    New Search

nicotinic acid (niacin) (nik--tin-ik) n.

a B vitamin. Nicotinic acid is required in the diet but can also be formed in small amounts in the body from the essential amino acid tryptophan. A deficiency of the vitamin leads to pellagra. Good sources of nicotinic acid are meat, yeast extracts, and some cereals.

Back  -    New Search

nictitation (nik-ti-tay-shn) n.

exaggerated and frequent blinking or winking of the eyes.

Back  -    New Search

nidation (ny-day-shn) n.

see IMPLANTATION.

Back  -    New Search

nidus (ny-ds) n.

a place in which bacteria have settled and multiplied because of particularly suitable conditions: a focus of infection.

Back  -    New Search

Niemann-Pick disease (nee-man pik) n.

a rare inherited disease of phospholipid metabolism in which sphingomyelin and lecithin accumulate in the bone marrow, spleen, and lymph nodes. It is characterized by enlargement of the liver and the spleen and by physical and mental retardation. [A. Niemann (1880–1921), German paediatrician; F. Pick (1868–1935), German physician]

Back  -    New Search

nifedipine (ny-fed-i-peen) n.

a calcium antagonist used in the treatment of angina and high blood pressure (hypertension). It is administered by mouth; side-effects include dizziness, headache, and nausea. Trade names: Adalat , Calcilat .

Back  -    New Search

night blindness (nyt) n.

the inability to see in dim light or at night. It is due to a disorder of the rods in the retina and can result from dietary deficiency of vitamin A. Its manifestations may progress to include xerophthalmia and keratomalacia. Night blindness may be caused by other retinal diseases, e.g. retinitis pigmentosa. Medical name: nyctalopia. Compare DAY BLINDNESS.

Back  -    New Search

night sweat n.

copious sweating during sleep. Night sweats may be an early indication of tuberculosis, AIDS, or other disease.

Back  -    New Search

night terror n.

the condition in which a young child, soon after falling asleep, starts screaming and appears terrified. The attack ceases when the child wakes up fully and is never remembered.

Back  -    New Search

nihilistic (ny-i-lis-tik) adj.

(in psychiatry) describing or relating to the state of a patient who believes that he and things about him do not exist.

Back  -    New Search

nikethamide (ni-keth--myd) n.

an analeptic drug used to raise the level of consciousness in comatose patients so that they can be encouraged to cough and bring up bronchial secretions. It is administered by mouth or injection.

Back  -    New Search

nipple (mamilla, papilla) (nip-l) n.

the protuberance at the centre of the breast. In females the milk ducts open at the nipple.

Back  -    New Search

niridazole (ni-rid--zohl) n.

an anthelmintic drug administered by mouth in the treatment of schistosomiasis. Niridazole should not be used in patients with impaired liver function.

Back  -    New Search

Nissl granules (nis-l) pl. n.

collections of dark-staining material, containing RNA, seen in the cell bodies of neurones on microscopic examination. [F. Nissl (1860–1919), German neuropathologist]

Back  -    New Search

nit (nit) n.

the egg of a louse. The eggs of head lice are firmly cemented to the hair; those of body lice are fixed to the clothing.

Back  -    New Search

nitrazepam (ny-traz--pam) n.

a hypnotic drug administered by mouth to treat insomnia and sleep disturbances. Trade name: Mogadon .

Back  -    New Search

nitric acid (ny-trik) n.

a strong corrosive mineral acid, the concentrated form of which is capable of producing severe burns of the skin. Swallowing the acid leads to intense burning pain and ulceration of the mouth and throat. Treatment is by immediate administration of alkaline solutions. Formula:
HNO_3
.

Back  -    New Search

nitric oxide n.

an important gaseous mediator that is involved in the manifestations of sepsis and septic shock. Formula:
NO
.

Back  -    New Search

nitrofurantoin (ny-troh-fewr-ant-oh-in) n.

a drug administered by mouth to treat bacterial infections of the urinary system. Trade names: Furadantin , Macrodantin .

Back  -    New Search

nitrogen (ny-tr-jn) n.

a gaseous element and a major constituent of air (79 per cent). Nitrogen is an essential constituent of proteins and nucleic acids and is obtained by humans in the form of protein-containing foods. Nitrogenous waste is excreted as urea. Liquid nitrogen is used to freeze some specimens before pathological examination. Symbol: N.

Back  -    New Search

nitrogen balance n.

the relationship between the nitrogen taken into the body and that excreted, denoting the balance between the manufacture and breakdown of the body mass. A negative nitrogen balance, when excretion exceeds intake, is usual after injury or operations as the energy requirements of the body are met disproportionately from endogenous sources.

Back  -    New Search

nitrogen mustard n.

see MUSTINE.

Back  -    New Search

nitroglycerin (ny-troh-glis-er-in) n.

see GLYCERYL TRINITRATE.

Back  -    New Search

nitroprusside (ny-troh-prus-syd) n.

a cyanide-containing drug used in the emergency treatment of high blood pressure. Given by controlled infusion into a vein, its effects and level in the blood must be closely monitored.

Back  -    New Search

nitrous oxide (ny-trs) n.

a colourless gas used as an anaesthetic with good analgesic properties. A mixture of nitrous oxide and oxygen is administered by inhalation for some dental procedures and in childbirth. Because it tends to excite the patient when used alone, nitrous oxide was formerly known popularly as laughing gas. Formula:
N_2O
.

Back  -    New Search

nm

abbrev. for nanometre.

Back  -    New Search

NMR n.

see NUCLEAR MAGNETIC RESONANCE.

Back  -    New Search

Nocardia (noh-kar-di) n.

a genus of rodlike or filamentous Gram-positive nonmotile bacteria found in the soil. N. asteroides the species that causes nocardiosis. N. madurae the species associated with the disease Madura foot.

Back  -    New Search

nocardiosis (noh-kar-di-oh-sis) n.

a disease caused by bacteria of the genus Nocardia, primarily affecting the lungs, skin, and brain, resulting in the formation of abscesses.

Back  -    New Search

noci- prefix

denoting pain or injury.

Back  -    New Search

nociceptive (noh-si-sep-tiv) adj.

describing nerve fibres, endings, or pathways that are concerned with the condition of pain.

Back  -    New Search

nociceptor (noh-si-sep-ter) n.

a receptor that responds to the stimuli responsible for the sensation of pain. Nociceptors may be interoceptors, responding to such stimuli as inflammation, or exteroceptors, sensitive to heat, etc.

Back  -    New Search

noct- (nocti-) prefix

denoting night.

Back  -    New Search

noctambulation (nok-tam-bew-lay-shn) n.

see SOMNAMBULISM.

Back  -    New Search

nocturia (nokt-yoor-i) n.

the passage of urine at night. Nocturia usually occurs in elderly men with enlarged prostate glands, and is a common reason for patients to request prostatectomy.

Back  -    New Search

nocturnal enuresis (nok-ter-nl) n.

see ENURESIS.

Back  -    New Search

node (nohd) n.

a small swelling or knot of tissue. See ATRIOVENTRICULAR NODE, LYMPH NODE, SINOATRIAL NODE. n. of Ranvier one of the gaps that occur at regular intervals in the myelin sheath of medullated nerve fibres, between adjacent Schwann cells. [L. A. Ranvier (1835–1922), French pathologist]

Back  -    New Search

nodule (nod-yool) n.

a small swelling or aggregation of cells.

Back  -    New Search

noma (noh-m) n.

a gangrenous infection of the mouth that spreads to involve the face. It is a severe form of ulcerative gingivitis that is usually found in debilitated or undernourished individuals.

Back  -    New Search

nonaccidental injury (NAI) (non-aks-i-den-t'l) n.

injury inflicted on babies and young children; the perpetrator is usually an adult - often a parent or step-parent. Known colloquially as the battered baby syndrome , it is most commonly seen in babies aged six months or less. It usually takes the form of bruising, particularly on the face; bite marks; burns or scalds, particularly cigarette burns; and bone injuries, especially spiral fractures of the long bones in the limbs and skull fractures. Internal injuries may be fatal. Careful examination often reveals several injuries of different ages, indicating long-term abuse. NAI usually has serious consequences for the child, including failure to thrive and behavioural problems.

Back  -    New Search

non compos mentis (non kom-ps men-tis) adj.

Latin: mentally incapable of managing one's own affairs.

Back  -    New Search

noninvasive (non-in-vay-siv) adj.

1 denoting techniques of investigation or treatment that do not involve penetration of the skin by needles or knives.

2 denoting tumours that do not spread into surrounding tissues (see BENIGN).
Top

Back  -    New Search

nonmaleficence (non-mal-ef-i-sns) n.

(in health care) the duty to avoid harming the interests of others.

Back  -    New Search

Nonne's syndrome (cerebellar syndrome) (non-z) n.

a form of cerebellar ataxia. See ATAXIA. [M. Nonne (1861–1959), German neurologist]

Back  -    New Search

nonsteroidal anti-inflammatory drug (non-steer-oi-d'l) n.

see NSAID.

Back  -    New Search

noradrenaline (norepinephrine) (nor--dren--lin) n.

a hormone, closely related to adrenaline, secreted by the medulla of the adrenal gland and also released as a neurotransmitter by sympathetic nerve endings. Among its many actions are constriction of small blood vessels leading to an increase in blood pressure, increase in the rate and depth of breathing, and relaxation of the smooth muscle in intestinal walls.

Back  -    New Search

norepinephrine (nor-epi-nef-rin) n.

see NORADRENALINE.

Back  -    New Search

norethisterone (nor-eth-ist-er-ohn) n.

a synthetic female sex hormone (see PROGESTOGEN) administered by mouth to treat menstrual disorders, including amenorrhoea. Its main use, however, is in oral contraceptives. Trade name: Primolut .

Back  -    New Search

norma (nor-m) n.

a view of the skull from one of several positions, from which it can be described or measured.

Back  -    New Search

normalization (nor-m-ly-zay-shn) n.

(in psychiatry) the process of making the living conditions of people with mental handicap as similar as possible to those of people who are not handicapped. This includes moves to living outside institutions and encouragement to cope with work, pay, social life, sexuality, and civil rights.

Back  -    New Search

normo-prefix

denoting normality.

Back  -    New Search

normoblast (nor-moh-blast) n.

a nucleated cell that forms part of the series giving rise to the red blood cells and is normally found in the blood-forming tissue of the bone marrow. See also ERYTHROBLAST, ERYTHROPOIESIS.

Back  -    New Search

normocyte (nor-moh-syt) n.

a red blood cell of normal size.
—normocytic adj.

Back  -    New Search

normotensive (nor-moh-ten-siv) adj.

describing the state in which the arterial blood pressure is within the normal range. Compare HYPERTENSION, HYPOTENSION.

Back  -    New Search

Norplant (nor-plahnt) n.

see LEVONORGESTREL.

Back  -    New Search

nortriptyline (nor-trip-ti-leen) n.

a tricyclic antidepressant drug that is administered by mouth to relieve all types of depression. Trade names: Allegron , Aventyl .

Back  -    New Search

nose (nohz) n.

the organ of olfaction, which also acts as an air passage that warms, moistens, and filters the air on its way to the lungs. It consists of a triangular cartilaginous projection in the front of the face that contains the nostrils (see NARES). It leads to the nasal cavity, which is lined with mucous membrane containing olfactory cells.

Back  -    New Search

nosebleed (nohz-bleed) n.

bleeding from the nose, which may be caused by physical injury or may be associated with fever, high blood pressure, or blood disorders. Medical name: epistaxis .

Back  -    New Search

noso- prefix

denoting disease.

Back  -    New Search

nosocomial infection (hospital infection) (nos-oh-koh-mi-l) n.

an infection whose development is favoured by a hospital environment, such as one acquired by a patient during a hospital visit or one developing among hospital staff. Such infections include fungal and bacterial infections and are aggravated by the reduced resistance of individual patients.

Back  -    New Search

nosology (nos-ol-ji) n.

the naming and classification of diseases.

Back  -    New Search

nostrils (nos-trilz) pl. n.

see NARES.

Back  -    New Search

notch (noch) n.

(in anatomy) an indentation, especially one in a bone.

Back  -    New Search

notifiable disease (noh-ti-fy-bl) n.

a disease that must be reported to the Health Authorities in order that speedy control and preventive action may be undertaken if necessary. In Great Britain such diseases include diphtheria, dysentery, food poisoning, infective jaundice, malaria, measles, poliomyelitis, tuberculosis, typhoid, and whooping cough.

Back  -    New Search

noxious (nok-shs) adj.

harmful: applied particularly to drugs with harmful effects.

Back  -    New Search

NSAID (nonsteroidal anti-inflammatory drug) n.

any one of a large group of drugs used for pain relief, particularly in rheumatic disease. NSAIDs act by inhibiting the enzymes responsible for the formation of prostaglandins, which are important mediators of inflammation. They include aspirin, azapropazone, diflunisal, ibuprofen, ketoprofen, and naproxen. Adverse effects include gastric bleeding and ulceration.

Back  -    New Search

nucha (new-k) n.

the nape of the neck.

Back  -    New Search

nuchal (new-kl) adj.

relating to the nape of the neck. n. fold the fold of skin at the back of the neck of the fetus. n. thickness scanning an ultrasound screening test performed during pregnancy at 10–14 weeks of gestation that examines the thickness of the nuchal fold as an aid to the prenatal diagnosis of chromosomal defects. The thicker the nuchal fold, the higher the risk of the baby having a chromosomal defect. See also ULTRASOUND MARKER.

Back  -    New Search

nucle- (nucleo-) prefix

denoting a cell nucleus.

Back  -    New Search

nuclear magnetic resonance (NMR) (new-kli-er) n.

the absorption and transmission of high-frequency radio waves by the nuclei of molecules when placed in a strong magnetic field. The effect is highly dependent on the concentration of hydrogen nuclei within each molecule, and is therefore particularly useful for analysing biological material. It has important applications in noninvasive diagnostic techniques (see MAGNETIC RESONANCE IMAGING).

Back  -    New Search

nuclear medicine n.

the use of radionuclides (especially technetium-99) as tracers to study the structure and function of organs of the body, often using a gamma camera. See also CARDIOLOGY.

Back  -    New Search

nuclease (new-kli-ayz) n.

an enzyme that catalyses the breakdown of nucleic acids by cleaving the bonds between adjacent nucleotides.

Back  -    New Search

nucleic acid (new-klee-ik) n.

either of two organic acids, DNA or RNA, present in the nucleus and in some cases the cytoplasm of all living cells.

Back  -    New Search

nucleolus (new-kli-oh-ls) n. (pl. nucleoli)

a dense spherical structure within the cell nucleus that disappears during cell division. The nucleolus contains RNA for the synthesis of ribosomes.

Back  -    New Search

nucleoprotein (new-kli-oh-proh-teen) n.

a compound that occurs in cells and consists of nucleic acid and protein tightly bound together.

Back  -    New Search

nucleoside (new-kli--syd) n.

a compound that consists of a nitrogen-containing base (a purine or pyrimidine) linked to a sugar. See also NUCLEOTIDE.

Back  -    New Search

nucleotide (new-kli--tyd) n.

a compound that consists of a nitrogen-containing base (a purine or pyrimidine) linked to a sugar and a phosphate group. Nucleic acids are long chains of linked nucleotides.

Back  -    New Search

nucleus (new-kli-s) n. (pl. nuclei)

1 the part of a cell that contains the genetic material, DNA. The nucleus also contains RNA, most of which is located in the nucleolus.

2 an anatomically and functionally distinct mass of nerve cells within the brain or spinal cord.
Top

3 the central part of the lens of the eye, which is harder than the outer cortex.
Top

Back  -    New Search

nucleus pulposus (pul-poh-ss) n.

the central part of an intervertebral disc, which consists of a soft pulpy material.

Back  -    New Search

nullipara (nul-ip-er-) n.

a woman who has never given birth to an infant capable of survival.

Back  -    New Search

nurse (ners) n.

a person who has completed a programme of basic nursing education and is qualified and authorized in his or her country to practise nursing. In Britain, the United Kingdom Central Council for Nursing, Midwifery and Health Visiting (see UKCC) is the registering statutory body and is responsible for the regulation of these professions in the interest of the public. Students of nursing undertake a three-year course to qualify as a registered n. (RN; adult health, child health, mental health, or learning disabilities). Before 1989 training culminated in qualification as a first-level n. , leading to registration either as a registered general n. (RGN), mental n. (RMN), sick children's n. (RSCN), or a n. for the mentally handicapped (RNMH), or as a second-level n. See DISTRICT NURSE, ENROLLED NURSE, FIRST-LEVEL NURSE, HEALTH VISITOR, MIDWIFE, NURSE PRACTITIONER, OCCUPATIONAL HEALTH NURSE, PRACTICE NURSE, SCHOOL NURSE, SECOND-LEVEL NURSE.

Back  -    New Search

nurse practitioner n.

a nurse specialist with advanced skills in physical diagnosis, psychosocial assessment, and management of patients' needs in primary health care. A key member of the health-care team, a nurse practitioner can be based in a group practice or a health centre. Patients may present to the nurse or be referred to her for direct consultation about health problems. The nurse practitioner has the authority to prescribe drugs and other treatments within agreed policies.

Back  -    New Search

nursing audit (ners-ing) n.

the process of collecting information from nursing reports and other documented evidence about patient care and assessing the quality of care by the use of quality assurance programmes. See QUALITY ASSURANCE, PERFORMANCE INDICATORS.

Back  -    New Search

nursing intervention n.

an act to implement the nursing care plan as part of the nursing process. See PLANNING.

Back  -    New Search

nursing models pl. n.

abstract frameworks, linking facts and phenomena, that assist nurses to plan nursing care, investigate problems related to clinical practice, and study the outcomes of nursing actions and interventions. Most of the nursing models in current usage are of North American origin but some have gained acceptance in the UK and are used in conjunction with the nursing process. See CASEY'S MODEL, HENDERSON'S MODEL, KING'S MODEL, NEUMANN'S MODEL, OREM'S MODEL, PEPLAU'S MODEL, ROPER, LOGAN, AND TIERNEY MODEL, ROY'S MODEL.

Back  -    New Search

nursing process n.

an individualized problem-solving approach to the nursing care of patients. It involves four stages: assessment (of the patient's problems), planning (how to resolve them), implementation (of the plans), and evaluation (of their success).

Back  -    New Search

nursing standard n.

a measure or measures by which nursing care can be judged or compared; the measures used are agreed upon by common consent. Standards for an agreed level of care for a particular purpose should be derived and set in a democratic way, with the participation of all those involved. See also QUALITY CIRCLE.

Back  -    New Search

nutation (new-tay-shn) n.

the act of nodding the head.

Back  -    New Search

nutrient (new-tri-nt) n.

a substance that must be consumed as part of the diet to provide a source of energy, material for growth, or substances for regulating growth or energy production. Nutrients include carbohydrates, proteins, fats, vitamins, and certain minerals, including the trace elements.

Back  -    New Search

nutrition (new-trish-n) n.

1 the study of food in relation to the physiological processes that depend on its absorption by the body. The science of nutrition includes the study of diets and deficiency diseases.

2 the intake of nutrients and their subsequent absorption and assimilation by the tissues. Patients who cannot be fed in a normal way can be given nutrients by tubes into the intestines (enteral feeding ) or by infusion into a vein (intravenous feeding ).
Top

Back  -    New Search

Nutrition and Energy

TABLE6.1 Normal body composition (of a 70kg man)

kg

water

42

intracellular

28

extracellular

14

solids

fat

12.6

protein

11.2

intracellular (muscle)

8.4

extracellular (collagen)

2.8

minerals

3.8

carbohydrate

0.4

TABLE6.2 Daily requirements for energy

Age

Energy kcal/kg

kj/kg

infant

3 months

120

500

child

4–6 years

90

380

adolescent

male

13–25 years

57

240

female

13–25 years

50

210

adult

male

46

190

female

40

170

TABLE6.3 Energy expenditure of a normal adult

Time

kcal

kj

Total range kcal (kj)

male

bed

8h

500

2100

non-occupational activities

8h

700–1500

3000–6300

work

8h

light

1100

4600

2300–3100 (9660–13000)

very heavy

2400

10100

3600–4400 (15100–18500)

female

bed

8h

420

1760

non-occupational activities

8h

580–980

2430–4120

work

8h

light

800

3360

1800–2200 (7560–9240)

heavy

1400

5880

2400–2700 (10100–11340)

TABLE6.2 Recommended daily amounts of some nutrients for population groups

Age range (years)

Occupational category

Thiamin (mg)

Riboflavin (mg)

Nicotinic acid equivalentsa (mg)

Total folate (µg)

Ascorbic acid (mg)

Vitamin A retinol equivalentsb (µg)

Vitamin D cholecalciferol (µg)

Calcium (mg)

Iron (mg)

boys

under 1

0.3

0.4

5

50

20

450

7.5

600

6

1

0.5

0.6

7

100

20

300

10

600

7

2

0.6

0.7

8

100

20

300

10

600

7

3–4

0.6

0.8

9

100

20

300

10

600

8

5–6

0.7

0.9

10

200

20

300

†

600

10

7–8

0.8

1.0

11

200

20

400

†

600

10

9–11

0.9

1.2

14

200

25

575

†

700

12

12–14

1.1

1.4

16

300

25

725

†

700

12

15–17

1.2

1.7

19

300

30

750

†

600

12

girls

under 1

0.3

0.4

5

50

20

450

7.5

600

6

1

0.4

0.6

7

100

20

300

10

600

7

2

0.5

0.7

8

100

20

300

10

600

7

3–4

0.6

0.8

9

100

20

300

10

600

8

5–6

0.7

0.9

10

200

20

300

†

600

10

7–8

0.8

1.0

11

200

20

400

†

600

10

9–11

0.8

1.2

14

300

25

575

†

700

12‡

12–14

0.9

1.4

16

300

25

725

†

700

12‡

15–17

0.9

1.7

19

300

30

750

†

600

12‡

men

18–34

sedentary

1.0

1.6

18

300

30

750

†

500

10

moderately active

1.2

1.6

18

300

30

750

†

500

10

very active

1.3

1.6

18

300

30

750

†

500

10

35–64

sedentary

1.0

1.6

18

300

30

750

†

500

10

moderately active

1.1

1.6

18

300

30

750

†

500

10

very active

1.3

1.6

18

300

30

750

†

500

10

65+

sedentary

0.9–1.0

1.6

18

300

30

750

†

500

10

women

18–54

most occupations

0.9

1.3

15

300

30

750

†

500

12‡

55+

sedentary

0.7–0.8

1.3

15

300

30

750

†

500

10

pregnancy

1.0

1.6

18

500

60

750

10

1200

13

lactation

1.1

1.8

21

400

60

1200

10

1200

15

Notes
a 1 nicotinic acid equivalent = 1mg available nicotinic acid or 60mg tryptophan.
b 1 retinol equivalent = 1µg retinol of 6µg ß-carotene or 12µg other biologically active carotenoids.
† No dietary sources may be necessary for children and adults who are sufficiently exposed to sunlight but during the winter children and adolescents should receive 10µg (400i.u.) daily by supplementation.
‡ This intake may not be sufficient for 10% of girls and women with large menstrual losses.
For the third trimester only.

Back  -    New Search

nux vomica (nuks vom-ik-) n.

the seed of the tree Strychnos nux-vomica, which contains the poisonous alkaloid strychnine.

Back  -    New Search

nyct- (nycto-) prefix

denoting night or darkness.

Back  -    New Search

nyctalopia (nik-t-loh-pi) n.

see NIGHT BLINDNESS.

Back  -    New Search

nyctophobia (nik-toh-foh-bi) n.

extreme fear of the dark. It is common in children and not unusual in normal adults.

Back  -    New Search

nymphae (nim-fee) pl. n.

the labia minora. See LABIUM.

Back  -    New Search

nympho- prefix

denoting
1 the labia minora.
2 female sexuality.

Back  -    New Search

nymphomania (nim-f-may-ni) n.

an extreme degree of sexual promiscuity in a woman.
—nymphomaniac adj., n.

Back  -    New Search

nystagmus (nis-tag-ms) n.

rapid involuntary movements of the eyes that may be from side to side, up and down, or rotatory. Nystagmus may be congenital and associated with poor sight; it also occurs in disorders of the part of the brain responsible for eye movements and in disorders of the organ of balance in the ear.

Back  -    New Search

nystatin (nis-t-tin) n.

an antifungal drug used especially to treat yeast infections, such as candidosis. It is formulated, often in conjunction with other drugs (e.g. tetracycline), as a cream for skin infections, as tablets for oral and intestinal infections, as pessaries or suppositories for vaginal or anal infections, or as eye drops for eye infections. Trade name: Nystan .

Back  -    New Search

O

O

symbol for oxygen.

Back  -    New Search

oat-cell carcinoma (small-cell lung cancer) (oht-sel) n.

carcinoma of the bronchus associated with the presence of oat cells (small cells with darkly staining nuclei). Oat-cell carcinoma is usually related to smoking and accounts for about one-quarter of bronchial carcinomas. It is very sensitive to chemotherapy and radiotherapy.

Back  -    New Search

obesity (oh-beess-iti) n.

the condition in which excess fat has accumulated in the body, mostly in the subcutaneous tissues. The accumulation of fat is usually caused by the consumption of more food than is required for producing enough energy for daily activities. A genetic element is also involved. See also LEPTIN.
—obese adj.

Back  -    New Search

objective (b-jek-tiv) n.

1 (in microscopy) the lens or system of lenses in a light microscope that is nearest to the object under examination and furthest from the eyepiece.

2 see BEHAVIOURAL OBJECTIVE.
Top

Back  -    New Search

objective signs pl. n.

the signs of a disease apparent to the examiner, as opposed to the symptoms experienced by the patient.

Back  -    New Search

obligate (ob-lig-ayt) adj.

describing an organism that is restricted to one particular way of life. Compare FACULTATIVE.

Back  -    New Search

oblique muscles (-bleek) pl. n.

1 two of the extrinsic muscles that control movement of the eyeball. See EYE.

2 two muscles in the wall of the abdomen.
Top

Back  -    New Search

obsession (b-sesh-n) n.

a recurrent thought, feeling, or action that is unpleasant and provokes anxiety but cannot be got rid of. Although an obsession dominates the person, he (or she) realizes its senselessness and struggles to expel it. Obsessions are a feature of obsessive-compulsive disorder (formerly known as obsessional neurosis ); they can be treated with behaviour therapy and also with psychotherapy and tranquillizers. See also NEUROSIS.
—obsessional adj.

Back  -    New Search

obsessive-compulsive disorder (b-ses-iv km-pul-siv) n.

see OBSESSION.

Back  -    New Search

obstetrics (b-stet-riks) n.

the branch of medical science concerned with the care of women during pregnancy, childbirth, and the period of about six weeks following the birth. Compare GYNAECOLOGY.
—obstetrical adj.—obstetrician (ob-stit-rish-n) n.

Back  -    New Search

obstruction (b-struk-shn) n.

the condition of being blocked, which may affect any tubular organ or structure. intestinal o. blockage of the intestines, producing symptoms of vomiting, distension, and abdominal pain; failure to pass flatus or faeces (complete constipation) is usual. The causes may be acute (e.g. hernia) or chronic (e.g. tumours, Crohn's disease).
—obstructive (b-struk-tiv) adj.

Back  -    New Search

obstructive sleep apnoea n.

see SLEEP APNOEA.

Back  -    New Search

obturation (ob-tewr-ay-shn) n.

obstruction of a body passage, usually by impaction of a foreign body, thickened secretions, or hard faeces.

Back  -    New Search

obturator (ob-tewr-ay-ter) n.

1 a wire or rod within a cannula or hollow needle for piercing tissues or fitting aspirating needles.

2 a removable form of denture that both closes a defect in the palate and also bears artificial teeth for cosmetic purposes.
Top

3 (o. muscle) either of two muscles that cover the outer surface of the anterior wall of the pelvis and are responsible for lateral rotation of the thigh and movements of the hip. o. foramen a large opening in the hip bone, below and slightly in front of the acetabulum. See also PELVIS.
Top

Back  -    New Search

obtusion (b-tew-zhn) n.

the weakening or blunting of normal sensations. This may be associated with disease.

Back  -    New Search

occipital bone (ok-sip-i-t'l) n.

a saucer-shaped bone of the skull that forms the back and part of the base of the cranium. At the base of the occipital are two condyles that articulate with the first (atlas) vertebra of the backbone. Between the condyles is the foramen magnum.

Back  -    New Search

occipito-anterior (ok-sip-i-toh-an-teer-i-er) adj.

describing the position of a baby at the time of delivery in which the back of the head is towards the front of the mother's pelvis.

Back  -    New Search

occipito-posterior (ok-sip-i-toh-pos-teer-i-er) adj.

describing the position of a baby at the time of delivery in which the back of the head is towards the mother's backbone.

Back  -    New Search

occiput (oks-ip-ut) n.

the back of the head.
—occipital adj.

Back  -    New Search

occlusion (-kloo-zhn) n.

1 the closing or obstruction of a hollow organ or part.

2 (in dentistry) the relation of the upper and lower teeth when they are in contact. See also MALOCCLUSION.
Top

Back  -    New Search

occlusive therapy (-kloo-siv) n.

a method of correcting strabismus (squint) in which the normal eye is covered to encourage use of the affected one.

Back  -    New Search

occult (-kult) adj.

not apparent to the naked eye; not easily detected. o. blood blood present in such small quantities, for example in the faeces, that it can only be detected microscopically or by chemical testing.

Back  -    New Search

occupational disease (ok-yoo-pay-shn-l) n.

any one of various specific diseases to which workers in certain occupations are particularly prone. Examples include the various forms of pneumoconiosis, cataracts in glassblowers, decompression sickness in divers, and infectious diseases contracted from animals by farm workers, such as woolsorter's disease (see ANTHRAX). See also INDUSTRIAL DISEASE, PRESCRIBED DISEASE.

Back  -    New Search

occupational health nurse n.

(in the UK) a nurse who has undergone a specialized course of study (full or part time) in the health care of people at work. An occupational health nurse is responsible for promoting a high degree of physical and mental health in industrial and commercial settings and in the NHS.

Back  -    New Search

occupational therapy n.

the treatment of physical and psychiatric conditions through specific activities in order to help people reach their maximum level of function and independence in all aspects of daily life.

Back  -    New Search

oct- (octa-, octi-, octo-) prefix

denoting eight.

Back  -    New Search

ocular (ok-yoo-ler) adj.

of or concerned with the eye or vision.

Back  -    New Search

oculist (ok-yoo-list) n.

an old term for an ophthalmologist.

Back  -    New Search

oculo- prefix

denoting the eye(s).

Back  -    New Search

oculogyric (ok-yoo-loh-jy-rik) adj.

causing or concerned with movements of the eye.

Back  -    New Search

oculomotor (ok-yoo-loh-moh-ter) adj.

concerned with eye movements. o. nerve the third cranial nerve (III), which supplies muscles in and around the eye, including those responsible for altering the size of the pupil and those that turn the eyeball in different directions.

Back  -    New Search

oculonasal (ok-yoo-loh-nay-zl) adj.

concerned with the eye and nose.

Back  -    New Search

oculoplethysmography (ok-yoo-loh-pleth-iz-mog-rfi) n.

measurement of the pressure inside the eyeball. A rising or above-normal pressure is an important indication of the presence of glaucoma.

Back  -    New Search

odont- (odonto-) prefix

denoting a tooth.

Back  -    New Search

odontalgia (od-on-tal-ji) n.

toothache.

Back  -    New Search

odontoid process (od-ont-oid) n.

a toothlike process from the upper surface of the axis vertebra.

Back  -    New Search

odontology (od-on-tol-ji) n.

the study of the teeth.

Back  -    New Search

odontoma (od-on-toh-m) n.

any tumour of tissues that give rise to teeth. See AMELOBLASTOMA.

Back  -    New Search

odontome (oh-don-tohm) n.

an abnormal mass of calcified dental tissue, usually representing a developmental abnormality.

Back  -    New Search

-odynia suffix

denoting pain in (a specified part).

Back  -    New Search

odynophagia (od-i-noh-fay-ji) n.

a sensation of pain behind the sternum as food or fluid is swallowed; particularly, the burning sensation experienced by patients with oesophagitis when hot, spicy, or alcoholic liquid is swallowed.

Back  -    New Search

oedema (ee-dee-m) n.

excessive accumulation of fluid in the body tissues: popularly known as dropsy . The resultant swelling may be local, as with an injury or inflammation, or more general. In generalized oedema there may be collections of fluid within the chest cavity, abdomen (see ASCITES), or within the air spaces of the lung (pulmonary o. ). It may result from heart or kidney failure, cirrhosis of the liver, acute nephritis, the nephrotic syndrome, starvation, allergy, or certain drugs. Diuretics are administered to get rid of the excess fluid. angio-o. see URTICARIA. subcutaneous o. oedema that commonly occurs in the legs and ankles; the swelling subsides with rest and elevation of the legs.
—oedematous adj.

Back  -    New Search

Oedipus complex (ee-dip-s) n.

repressed sexual feelings of a child for its opposite-sexed parent, combined with rivalry towards the same-sexed parent: in Freudian psychoanalytic theory, this is said to be a normal stage of development. Arrest of development at the Oedipal stage is said to be responsible for sexual deviations and other neurotic behaviour.

Back  -    New Search

oesophag- (oesophago-) prefix

denoting the oesophagus.

Back  -    New Search

oesophageal ulcer (ee-sof--jee-l) n.

a peptic ulcer in the oesophagus, associated with reflux oesophagitis.

Back  -    New Search

oesophageal varices pl. n.

dilated veins in the lower oesophagus due to portal hypertension. These veins may rupture and bleed, resulting in haematemesis. Bleeding may be arrested by a compression balloon, by sclerotherapy, by applying elastic bands via an endoscope, or by intravenous infusions of vasopressin or somatostatin.

Back  -    New Search

oesophagectomy (ee-sof--jek-tmi) n.

surgical removal of part or the whole of the oesophagus.

Back  -    New Search

oesophagitis (ee-sof--jy-tis) n.

inflammation of the oesophagus. corrosive o. oesophagitis caused by the ingestion of caustic acid or alkali. Infective o. oesophagitis caused by infection with Candida or, more rarely, by viruses. It is common in AIDS patients. reflux o. the commonest form of oesophagitis, caused by frequent regurgitation of acid and peptic juices from the stomach. It may be associated with a hiatus hernia. The main symptoms are heartburn, regurgitation of bitter fluid, and sometimes difficulty in swallowing; complications include bleeding, narrowing (stricture) of the oesophageal canal, and ulceration.

Back  -    New Search

oesophagocele (ee-sof--goh-seel) n.

protrusion of the lining (mucosa) of the oesophagus through a tear in its muscular wall.

Back  -    New Search

oesophagogastroduodenoscopy (OGD) (ee-sof--goh-gas-troh-dew--di-nos-kpi) n.

endoscopic examination of the upper alimentary tract using a fibreoptic or video instrument. See also GASTROSCOPE.

Back  -    New Search

oesophagoscope (ee-sof--goh-skohp) n.

an illuminated optical instrument that is used to inspect the interior of the oesophagus, dilate its canal, obtain material for biopsy, or remove a foreign body.
—oesophagoscopy (ee-sof--gos-k-pi) n.

Back  -    New Search

oesophagostomy (ee-sof--gost-mi) n.

a surgical operation in which the oesophagus is opened onto the neck. It is usually performed after operations on the throat as a temporary measure to allow feeding.

Back  -    New Search

oesophagotomy (ee-sof--got-mi) n.

surgical opening of the oesophagus in order to inspect its interior or to remove or insert something.

Back  -    New Search

oesophagus (ee-sof--gs) n.

the gullet: a muscular tube, about 23 cm long, that extends from the pharynx to the stomach. It is lined with mucous membrane, whose secretions lubricate food as it passes from the mouth to the stomach.
—oesophageal (ee-sof--jee-l) adj.

Back  -    New Search

oestradiol (ees-tr-dy-ol) n.

the major female sex hormone produced by the ovary. See OESTROGEN.

Back  -    New Search

oestriol (ees-tri-ol) n.

one of the female sex hormones produced by the ovary. See OESTROGEN.

Back  -    New Search

oestrogen (ees-tr-jn) n.

one of a group of steroid hormones (including oestriol, oestrone, and oestradiol) that control female sexual development. Oestrogens are synthesized mainly by the ovary; small amounts are also produced by the adrenal cortex, testes, and placenta. Naturally occurring and synthetic oestrogens are administered by mouth or injection to treat amenorrhoea, menopausal symptoms (see HORMONE REPLACEMENT THERAPY), and androgen-dependent cancers, and to inhibit lactation. Synthetic oestrogens are a major constituent of oral contraceptives.
—oestrogenic adj.

Back  -    New Search

oestrone (ees-trohn) n.

one of the female sex hormones produced by the ovary. See OESTROGEN.

Back  -    New Search

ofloxacin (oh-floks--sin) n.

a quinolone antibiotic used to treat urinary-tract and sexually transmitted infections. It is administered by mouth or injection. Trade name: Tarivid .

Back  -    New Search

OGD n.

see OESOPHAGOGASTRODUODENOSCOPY.

Back  -    New Search

ohm (ohm) n.

the SI unit of electrical resistance, equal to the resistance between two points on a conductor when a constant potential difference of 1 volt applied between these points produces a current of 1 ampere. Symbol: .

Back  -    New Search

-oid suffix

denoting like; resembling.

Back  -    New Search

ointment (oint-mnt) n.

a greasy material, usually containing a medicament, applied to the skin or mucous membranes.

Back  -    New Search

olecranon process (oh-lek-r-non) n.

the large process of the ulna that projects behind the elbow joint.

Back  -    New Search

oleic acid (oh-lee-ik) n.

see FATTY ACID.

Back  -    New Search

oleo- prefix

denoting oil.

Back  -    New Search

oleum (oh-li-m) n.

(in pharmacy) an oil.

Back  -    New Search

o. morrhuae

cod-liver oil. o. olivae olive oil. o. ricini castor oil.

Back  -    New Search

olfaction (ol-fak-shn) n.

1 the sense of smell.

2 the process of smelling. Sensory cells in the mucous membrane that lines the nasal cavity are stimulated by the presence of chemical particles dissolved in the mucus.
Top

—olfactory (ol-fak-ter-i) adj.

Back  -    New Search

olfactory nerve n.

the first cranial nerve (I): the special sensory nerve of smell. Fibres of the nerve run upwards from smell receptors in the nasal mucosa and join to form the olfactory tract to the brain.

Back  -    New Search

olig- (oligo-) prefix

denoting 1 few.

2 a deficiency.
Top

Back  -    New Search

oligaemia (ol-ig-ee-mi) n.

see HYPOVOLAEMIA.

Back  -    New Search

oligodactylism (ol-i-goh-dak-til-izm) n.

the congenital absence of some of the fingers and toes.

Back  -    New Search

oligodipsia (ol-i-goh-dip-si) n.

a condition in which thirst is diminished or absent.

Back  -    New Search

oligodontia (ol-i-goh-don-shi) n.

the congenital absence of some of the teeth.

Back  -    New Search

oligohydramnios (ol-i-goh-hy-dram-ni-os) n.

a condition in which the amount of amniotic fluid bathing a fetus during pregnancy is abnormally small (0–200 ml in the third trimester).

Back  -    New Search

oligomenorrhoea (ol-i-goh-men--ree-) n.

sparse or infrequent menstruation.

Back  -    New Search

oligo-ovulation (ol-i-goh-ov-yoo-lay-shn) n.

infrequent occurrence of ovulation.

Back  -    New Search

oligospermia (ol-i-goh-sper-mi) n.

the presence of less than the normal amount of spermatozoa in the semen (see SEMINAL ANALYSIS). In oligospermia there are less than 20 million spermatozoa per ml with poor motility and of ten including many bizarre and immature forms. It is a cause of male infertility.

Back  -    New Search

oliguria (ol-ig-yoor-i) n.

the production of an abnormally small volume of urine. This may be a result of copious sweating, kidney disease, oedema, loss of blood, diarrhoea, or poisoning.

Back  -    New Search

olive (ol-iv) n.

a smooth oval swelling in the upper part of the medulla oblongata on each side. It contains a mass of nerve cells, mainly grey matter (olivary nucleus ).
—olivary adj.

Back  -    New Search

olive oil n.

an oil extracted from olives and used as a demulcent, faecal softener, and intestinal lubricant.

Back  -    New Search

Ollier's disease (ol-i-ayz) n.

see DYSCHONDROPLASIA. [L. L. X. E. Ollier (1830–1900), French surgeon]

Back  -    New Search

-ology suffix.

see -LOGY.

Back  -    New Search

olsalazine (ol-sal--zeen) n.

a salicylate preparation used to treat mild ulcerative colitis. It is administered by mouth. Trade name: Dipentum .

Back  -    New Search

om- (omo-) prefix

denoting the shoulder.

Back  -    New Search

-oma suffix

denoting a tumour.

Back  -    New Search

omentectomy (oh-men-tek-tmi) n.

the removal of all or part of the omentum.

Back  -    New Search

omentopexy (oh-men-toh-peks-i) n.

an operation in which the omentum is attached to some other tissue, usually the abdominal wall in order to improve blood flow through the liver.

Back  -    New Search

omentum (epiploon) (oh-men-tm) n.

a double layer of peritoneum attached to the stomach and linking it with other abdominal organs. great o. a highly folded portion of the omentum that covers the intestines in an apron-like fashion. It acts as a heat insulator and prevents friction between abdominal organs. lesser o. a portion of the omentum that links the stomach with the liver.
—omental adj.

Back  -    New Search

omeprazole (oh-mep-r-zohl) n.

a drug used to treat gastric and duodenal ulcers and the Zollinger-Ellison syndrome (see PROTON-PUMP INHIBITOR). Administered by mouth, it is long-acting and need only be taken once a day. Trade name: Losec .

Back  -    New Search

omphal- (omphalo-) prefix

denoting the navel or umbilical cord.

Back  -    New Search

omphalitis (om-f-ly-tis) n.

inflammation of the navel, especially in newborn infants.

Back  -    New Search

omphalocele (om-f-loh-seel) n.

an umbilical hernia.

Back  -    New Search

omphalus (om-f-ls) n.

see UMBILICUS.

Back  -    New Search

Onchocerca (onk-oh-ser-k) n.

a genus of parasitic worms (see FILARIA) occurring in central Africa and central America. O. volvulus the cause of onchocerciasis.

Back  -    New Search

onchocerciasis (onk-oh-ser-ky--sis) n.

a tropical disease of the skin and underlying connective tissue caused by the parasitic worm Onchocerca volvulus. Fibrous nodular tumours grow around the adult worms in the skin; the migration of the larvae into the eye can cause total or partial blindness (river blindness ). The drugs suramin, diethylcarbamazine, and ivermectin are used in treatment.

Back  -    New Search

onco- prefix

denoting 1 a tumour.

2 volume.
Top

Back  -    New Search

oncogene (onk-oh-jeen) n.

a gene in viruses and mammalian cells that can cause cancer; it results from the mutation of a normal gene and is capable of both initiation and continuation of malignant transformation of normal cells. Oncogenes probably produce peptides (growth factors) regulating cell division that, under certain conditions, become uncontrolled and may transform a normal cell to a malignant state.

Back  -    New Search

oncogenesis (onk-oh-jen-i-sis) n.

the development of a new abnormal growth (a benign or malignant tumour).

Back  -    New Search

oncogenic (onk-oh-jen-ik) adj.

describing a substance, organism, or environment that is known to be a causal factor in the production of a tumour. Some viruses are oncogenic. See also CARCINOGEN.

Back  -    New Search

oncology n. (onk-ol-ji) n.

the study and practice of treating tumours. It is often subdivided into medical, surgical, and radiation oncology.
—oncologist n.

Back  -    New Search

oncolysis (onk-ol-i-sis) n.

the destruction of tumours and tumour cells. This may occur spontaneously or, more usually, in response to treatment with drugs or radiotherapy.

Back  -    New Search

oncometer (onk-om-it-er) n.

see PLETHYS-MOGRAPHY.

Back  -    New Search

oncotic (onk-ot-ik) adj.

1 characterized by a tumour or swelling.

2 relating to an increase in volume or pressure.
Top

Back  -    New Search

ondansetron (on-dan-si-tron) n.

a drug used to control severe nausea and vomiting, especially when this is caused by chemotherapy and radiotherapy. Trade name: Zofran .

Back  -    New Search

onomatomania (on-oh-mat-oh-may-ni) n.

the repeated intrusion of a specific word or a name into a person's thoughts: a form of obsession.

Back  -    New Search

ontogeny (on-toj--ni) n.

the history of the development of an individual from the fertilized egg to maturity.

Back  -    New Search

onych- (onycho-) prefix

denoting the nail(s).

Back  -    New Search

onychogryphosis (on-i-koh-grif-oh-sis) n.

thickening and lateral curvature of a nail, usually the big toenail.

Back  -    New Search

onycholysis (on-i-kol-i-sis) n.

separation or loosening of part or all of a nail from its bed. The condition may occur in psoriasis and in fungal infection of the skin and nail bed.

Back  -    New Search

onychomycosis (on-i-koh-my-koh-sis) n.

fungus infection of the nails caused by dermatophytes or Candida. The nails become yellow, opaque, and thickened. See also TINEA.

Back  -    New Search

O'nyong nyong fever (joint-breaker fever) (oh-n'yong-n'yong) n.

an East African disease caused by an arbovirus and transmitted to man by mosquitoes of the genus Anopheles. Symptoms include rigor, severe headache, an irritating rash, fever, and pains in the joints.

Back  -    New Search

oo- prefix

denoting an egg; ovum.

Back  -    New Search

oocyte (oh--syt) n.

a cell in the ovary that undergoes meiosis to form an ovum. See OOGENESIS.

Back  -    New Search

oocyte donation n.

the transfer of oocytes from one woman to another. It allows the recipient, who is unable to ovulate, to achieve a normal pregnancy.

Back  -    New Search

oogenesis (oh--jen-i-sis) n.

the process by which mature ova are produced in the ovary (see illustration). Primordial germ cells multiply to form oogonia, which start their first meiotic division to become oocytes in the fetus and complete it at ovulation. Fertilization stimulates the completion of the second meiotic division, which produces a mature ovum.

Back  -    New Search

oogonium (oh--goh-nim) n. (pl. oogonia)

a cell produced at an early stage in the formation of an ovum. See OOGENESIS.

Back  -    New Search

oophor- (oophoro-) prefix

denoting the ovary.

Back  -    New Search

oophorectomy (ovariectomy) (oh--f-rek-tmi) n.

surgical removal of an ovary.

Back  -    New Search

oophoritis (ovaritis) (oh--f-ry-tis) n.

inflammation of an ovary, either on the surface or within the organ. Oophoritis may be associated with infection of the Fallopian tubes (see SALPINGITIS) or the lower part of the abdominal cavity.

Back  -    New Search

oophoron (oh-off--ron) n.

the ovary.

Back  -    New Search

oophoropexy (oh-off--roh-peks-i) n.

the stitching of a displaced ovary to the wall of the pelvic cavity.

Back  -    New Search

oophorosalpingectomy (oh-off--roh-sal-pin-jek-tmi) n.

surgical removal of an ovary and its associated Fallopian tube.

Back  -    New Search

opacity (-pas-iti) n.

1 lack of transparency.

2 an opaque area, as occurs in the lens of the eye in cataract.
Top

Back  -    New Search

operating microscope (op-er-ayt-ing) n.

a binocular microscope commonly used in microsurgery. The field of operation is illuminated through the objective lens by a light source within the microscope.

Back  -    New Search

operculum (oh-per-kew-lm) n. (pl. opercula)

a plug of mucus that blocks the cervical canal of the uterus in a pregnant woman. When the cervix begins to dilate at the start of labour, the operculum, slightly stained with blood, comes away as a discharge (‘show’).

Back  -    New Search

operon (op-er-on) n.

a group of closely linked genes that regulate the production of enzymes in bacteria.

Back  -    New Search

ophthalm- (ophthalmo-) prefix

denoting the eye or eyeball. Examples: ophthalmectomy (surgical removal of); ophthalmorrhexis (rupture of).

Back  -    New Search

ophthalmia (off-thal-mi) n.

inflammation of the eye, particularly the conjunctiva (see CONJUNCTIVITIS). o. neonatorum a form of conjunctivitis occurring in newborn infants, who contract the disease as they pass through an infected birth canal. The two most common infections are gonorrhoea and Chlamydia. Unless treated (with antibiotics), the infection may cause permanent eye disease. sympathetic o. a granulomatous uveitis affecting all parts of the uveal tract of both eyes that may develop after trauma or (more rarely) eye surgery.

Back  -    New Search

ophthalmic (off-thal-mik) adj.

concerned with the eye.

Back  -    New Search

ophthalmitis (off-thal-my-tis) n.

inflammation of the eye. See CONJUNCTIVITIS, UVEITIS.

Back  -    New Search

ophthalmologist (off-thal-mol--jist) n.

a doctor who specializes in the diagnosis and treatment of eye diseases.

Back  -    New Search

ophthalmology (off-thal-mol-ji) n.

the branch of medicine that is devoted to the study and treatment of eye diseases.
—ophthalmological adj.

Back  -    New Search

ophthalmometer (off-thal-mom-it-er) n.

see KERATOMETER.

Back  -    New Search

ophthalmoplegia (off-thal-moh-plee-ji) n.

paralysis of the muscles of the eye. It may accompany exophthalmos due to thyrotoxicosis. external o. ophthalmoplegia affecting the muscles that move the eye. internal o. ophthalmoplegia affecting the iris and ciliary muscle.

Back  -    New Search

ophthalmoscope (off-thal-m-skohp) n.

an instrument for examining the interior of the eye (see illustration).

—ophthalmoscopy (off-thal-mos-k-pi) n.

Back  -    New Search

ophthalmotomy (off-thal-mot-mi) n.

the operation of making an incision in the eyeball.

Back  -    New Search

ophthalmotonometer (tonometer) (off-thal-moh-toh-nom-it-er) n.

a small instrument for measuring the pressure inside the eye by applying pressure to the cornea. There are several types.

Back  -    New Search

-opia suffix

denoting a defect of the eye or of vision.

Back  -    New Search

opiate (oh-pit) n.

one of a group of drugs derived from opium, including apomorphine, codeine, diamorphine (heroin), morphine, and papaverine. Opiates depress the central nervous system: they relieve pain, suppress coughing, and stimulate vomiting. See also NARCOTIC.

Back  -    New Search

opisth- (opistho-) prefix

denoting 1 dorsal; posterior.

2 backwards.
Top

Back  -    New Search

opisthorchiasis (op-iss-thor-ky--sis) n.

a condition caused by the presence of the parasitic fluke Opisthorchis in the bile ducts. Heavy infections can damage the tissues of the bile duct and liver and may progress to cirrhosis. The disease is treated with chloroquine.

Back  -    New Search

Opisthorchis (op-iss-thor-kis) n.

a genus of parasitic flukes occurring in E Europe and parts of SE Asia. The adult flukes, which live in the bile ducts, can cause opisthorchiasis.

Back  -    New Search

opisthotonos (op-iss-thot-oh-ns) n.

the position of the body in which the head, neck, and spine are arched backwards. It is assumed involuntarily by patients with tetanus and strychnine poisoning.

Back  -    New Search

opium (oh-pim) n.

an extract from the poppy Pa paver somni ferum, which has analgesic and narcotic action due to its content of morphine. It has the same uses and side-effects as morphine and prolonged use may lead to dependence. See also OPIATE.

Back  -    New Search

opponens (oh-poh-nenz) n.

one of a group of muscles in the hand that bring the digits opposite to other digits. o. pollicis the principal muscle causing opposition of the thumb.

Back  -    New Search

opportunistic (op-er-tew-nis-tik) adj.

denoting a disease that occurs when the patient's immune system is impaired by, for example, an infection, another disease, or drugs. The infecting organism rarely causes the disease in healthy persons. Opportunistic infections, such as Pneumocystis carinii pneumonia and those caused by Mycobacterium (see MAI COMPLEX), are common in patients with AIDS.

Back  -    New Search

OPSI n.

opportunistic post-splenectomy infection: infection that occurs after surgical removal of the spleen (see SPLENECTOMY). It results from immune deficiency caused by loss of the spleen.

Back  -    New Search

-opsia suffix

denoting a condition of vision.

Back  -    New Search

opsoclonus (op-soh-kloh-ns) n.

a series of erratic eye movements in any direction, which is seen in people with disease of the cerebellum.

Back  -    New Search

opsonic index (op-son-ik) n.

a numerical measurement of the power of a person's serum to attack invading bacteria and prepare them for destruction by phagocytes.

Back  -    New Search

opsonin (op-sn-in) n.

a serum component that attaches itself to invading bacteria and apparently makes them more susceptible to phagocytosis.

Back  -    New Search

opt- (opto-) prefix

denoting vision or the eye.

Back  -    New Search

optic (op-tik) adj.

concerned with the eye or vision. o. atrophy degeneration of the optic nerve. o. chiasma (o. commissure ) the X-shaped structure formed by the two nerves as nerve fibres from the nasal side of the retina of each eye cross over to join fibres from the lateral side of the retina of the opposite eye (see illustration). o. disc (o. papilla ) the start of the optic nerve, where nerve fibres from the rods and cones leave the eyeball. See BLIND SPOT. o. nerve the second cranial nerve (II), which is responsible for vision. It passes into the skull behind the eyeball to reach the optic chiasma, after which the visual pathway continues to the occipital lobe. o. neuritis see RETROBULBAR NEURITIS.

Back  -    New Search

optician (op-tish-n) n.

a person who either makes and fits glasses (dispensing o. ) or who can both test people for glasses and dispense glasses (ophthalmic o. or optometrist ).

Back  -    New Search

optometer (refractometer) (op-tom-it-er) n.

an instrument for measuring the refraction of the eye.

Back  -    New Search

optometrist (op-tom-i-trist) n.

see OPTICIAN.

Back  -    New Search

optometry (op-tom-itri) n.

the practice of testing the visual acuity of eyes and prescribing lenses to correct defects of vision.

Back  -    New Search

oral (or-l) adj.

1 relating to the mouth.

2 taken by mouth: applied to medicines, etc.
Top

Back  -    New Search

oral contraceptive n.

the Pill: a preparation, consisting of one or more synthetic female sex hormones, taken by women to prevent conception. Most oral contraceptives are combined pills, consisting of an oestrogen, which blocks the normal process of ovulation, and a progestogen, which acts on the pituitary gland to block the normal control of the menstrual cycle.

Back  -    New Search

oral hypoglycaemic drug (hy-poh-gly-see-mik) n.

one of the group of drugs that reduce the level of glucose in the blood and are taken by mouth for the treatment of noninsulin-dependent (Type II) diabetes mellitus. They include the sulphonylurea drugs and metformin (a biguanide).

Back  -    New Search

oral rehydration therapy (ORT) (ree-hy-dray-shn) n.

the administration of an isotonic solution of various sodium salts, potassium chloride, glucose, and water to treat acute diarrhoea, particularly in children. In developing countries it is the mainstay of treatment for cholera. Preparations in clinical use include Dioralyte and Rehidrat .

Back  -    New Search

Orbenin (or-ben-in) n.

see CLOXACILLIN SODIUM.

Back  -    New Search

orbicularis (or-bik-yoo-lar-iss) n.

either of two circular muscles of the face. o. oculi the muscle around each orbit that is responsible for closing the eye. o. oris the muscle around the mouth that closes and compresses the lips.

Back  -    New Search

orbit (or-bit) n.

the cavity in the skull that contains the eye. It is formed from parts of the frontal, sphenoid, zygomatic, lacrimal, ethmoid, palatine, and maxillary bones.
—orbital adj.

Back  -    New Search

orbitotomy (or-bit-ot-mi) n.

surgical removal of part of the orbital bones to gain access to the orbital space.

Back  -    New Search

orchi- (orchido-, orchio-) prefix

denoting the testis or testicle.

Back  -    New Search

orchidalgia (or-kid-al-ji) n.

pain in the testicle. It may be caused by a hernia in the groin, a stone in the lower ureter, or a varicocele.

Back  -    New Search

orchidectomy (or-kid-ek-tmi) n.

surgical removal of a testis, usually to treat such diseases as seminoma (a malignant tumour of the testis).

Back  -    New Search

orchidopexy (or-kid-oh-peks-i) n.

the operation of mobilizing an undescended testis in the groin and fixing it in the scrotum.

Back  -    New Search

orchidotomy (or-kid-ot-mi) n.

an incision into the testis, usually done to obtain biopsy material for histological examination.

Back  -    New Search

orchis (or-kis) n.

the testis or testicle.

Back  -    New Search

orchitis (or-ky-tis) n.

inflammation of the testis. This causes pain, redness, and swelling of the scrotum, and may be associated with inflammation of the epididymis (epididymo-orchitis ). The condition is usually caused by infection spreading down the vas deferens but can develop in mumps (mumps o. ).

Back  -    New Search

orciprenaline (or-si-pren--leen) n.

a drug used to relieve bronchitis and asthma. It has the same actions and side-effects as isoprenaline. Trade name: Alupent .

Back  -    New Search

Orem's model (or-mz) n.

a model for nursing based on the self-care deficit theory of nursing, in which patients are seen as able, when they are well, to initiate and perform activities on their own behalf, in order to maintain life, health, and well-being. Infants, children, the elderly, the disabled, and the ill may require assistance or complete care with these activities. See also NURSING MODELS. [D. Orem (1914– ), US nurse theorist]

Back  -    New Search

orf (orf) n.

an infectious disease of sheep and goats caused by a parapoxvirus. Those bottle-feeding infected lambs may develop a painful nodule on the fingers or hands; it resolves spontaneously.

Back  -    New Search

organ (or-gn) n.

a part of the body, composed of more than one tissue, that forms a structural unit responsible for a particular function (or functions). o. of Corti (spiral o. ) the sense organ of the cochlea, which converts sound signals into nerve impulses that are transmitted to the brain via the cochlear nerve. [A. Corti (1822–88), Italian anatomist]

Back  -    New Search

organelle (or-g-nel) n.

a structure within a cell that is specialized for a particular function.

Back  -    New Search

organic (or-gan-ik) adj.

1 relating to any or all of the organs of the body. o. disorder a disorder associated with changes in the structure of an organ or tissue. Compare FUNCTIONAL DISORDER.

2 describing chemical compounds containing carbon, found in all living systems.
Top

Back  -    New Search

organism (or-gn-izm) n.

any living thing, which may consist of a single cell (see MICROORGANISM) or a group of differentiated but interdependent cells.

Back  -    New Search

organo- prefix

denoting organ or organic.

Back  -    New Search

orgasm (or-gazm) n.

the climax of sexual excitement.

Back  -    New Search

oriental sore (Baghdad boil, Delhi boil, Aleppo boil) (or-i-en-t'l) n.

a skin disease, occurring in tropical and subtropical Africa and Asia, caused by the parasitic protozoan Leishmania tropica. The disease takes the form of a slow-healing open sore or ulcer, which sometimes becomes secondarily infected with bacteria.

Back  -    New Search

orientation (or-i-en-tay-shn) n.

(in psychology) awareness of oneself in time, space, and place. Orientation may be disturbed in such conditions as organic brain disease, toxic drug states, and concussion.

Back  -    New Search

orifice (o-ri-fis) n.

an opening in an anatomical part. See OSTIUM.

Back  -    New Search

origin (o-ri-jin) n.

(in anatomy) 1 the point of attachment of a muscle that remains relatively fixed during contraction of the muscle. Compare INSERTION.

2 the point at which a nerve or blood vessel branches from a main nerve or blood vessel.
Top

Back  -    New Search

ornithine (or-ni-theen) n.

an amino acid produced in the liver as a by-product during the conversion of ammonia to urea.

Back  -    New Search

ornithosis (or-ni-thoh-sis) n.

see PSITTACOSIS.

Back  -    New Search

oro- prefix

denoting the mouth.

Back  -    New Search

oropharynx (o-roh-fa-rinks) n.

the part of the pharynx that lies between the soft palate and the hyoid bone.

Back  -    New Search

orphenadrine (or-fen--dreen) n.

a drug that relieves spasm in muscle, administered by mouth or injection to treat all types of parkinsonism. Trade names: Disipal , Norflex .

Back  -    New Search

ORT n.

see ORAL REHYDRATION THERAPY.

Back  -    New Search

ortho- prefix

denoting 1 straight.

2 normal.
Top

Back  -    New Search

orthodiagraph (orth-dy--grahf) n.

an X-ray photograph designed to give an undistorted picture of part of the body so that accurate measurements may be made from it.

Back  -    New Search

orthodontics (orth-don-tiks) n.

the branch of dentistry concerned with the growth and development of the face and jaws and the treatment of irregularities of the teeth by means of various orthodontic appliances .
—orthodontic adj.

Back  -    New Search

orthopaedics (orth-pee-diks) n.

the science or practice of correcting deformities caused by disease of or damage to the bones and joints of the skeleton.
—orthopaedic adj.

Back  -    New Search

orthopnoea (or-thop-nee-) n.

breathlessness that prevents the patient from lying down, so that he has to sleep propped up in bed or sitting in a chair.
—orthopnoeic adj.

Back  -    New Search

orthoptics (or-thop-tiks) n.

the practice of using nonsurgical methods, particularly eye exercises, to treat abnormalities of vision and of coordination of eye movements (most commonly strabismus and amblyopia).
—orthoptist n.

Back  -    New Search

orthoptoscope (or-thop-toh-skohp) n.

see AMBLYOSCOPE.

Back  -    New Search

orthosis (or-thoh-sis) n.

a surgical appliance that exerts external forces on part of the body to support joints or correct deformity.

Back  -    New Search

orthostatic (orth-stat-ik) adj.

relating to the upright position of the body: used when describing this posture or a condition caused by it.

Back  -    New Search

orthotics (or-thot-iks) n.

the science and practice of fitting surgical appliances to assist weakened joints.

Back  -    New Search

Ortolani manoeuvre (or-toh-lah-ni m-noo-ver) n.

a test for congenital dislocation of the hip in which, with the baby lying supine and the pelvis steadied with one hand, the examiner attempts to relocate a dislocated hip by gently abducting the hip while simultaneously pushing forward on the greater trochanter. If the hip is dislocated, it will relocate with a detectable and sometimes audible clunk. [M. Ortolani (20th century), Italian orthopaedic surgeon]

Back  -    New Search

os_1 (oss) n. (pl. ossa)

a bone.

Back  -    New Search

os_2 n. (pl. ora)

the mouth or a mouthlike part.

Back  -    New Search

osche- (oscheo-) prefix

denoting the scrotum.

Back  -    New Search

oscillation (oss-i-lay-shn) n.

a regular side-to-side movement; vibration.

Back  -    New Search

oscilloscope (oss-il--skohp) n.

a cathoderay tube designed to display electronically a wave form corresponding to the electrical data fed into it. Oscilloscopes are used to provide a continuous record of many different measurements, such as the activity of the heart and brain. See ELECTROCARDIOGRAPHY, ELECTROENCEPHALOGRAPHY.

Back  -    New Search

osculum (osk-yoo-lm) n.

(in anatomy) a small aperture.

Back  -    New Search

Osgood-Schlatter disease (Schlatter's disease) (oz-guud shlat-er) n.

inflammation and swelling at the site of insertion of the main quadriceps tendon at the top of the tibia, just below the knee (see APOPHYSITIS, OSTEOCHONDRITIS). It is common in adolescence and results from excessive physical activity. [R. B. Osgood (1873–1956), US orthopaedist; C. Schlatter (1864–1934), Swiss surgeon]

Back  -    New Search

-osis suffix

denoting 1 a diseased condition.

2 any condition.
Top

3 an increase or excess.
Top

Back  -    New Search

Osler's nodes (ohss-lerz) pl. n.

small tender swellings in or beneath the skin at the ends of the fingers and toes, seen in subacute bacterial endocarditis. [Sir W. Osler (1849–1919), Canadian physician]

Back  -    New Search

osm- (osmo-) prefix

denoting 1 smell or odour.

2 osmosis or osmotic pressure.
Top

Back  -    New Search

osmolality (oz-moh-lal-iti) n.

the osmotic pressure of a substance expressed in terms of osmoles of substance per kg of water. Compare OSMOLARITY.

Back  -    New Search

osmolarity (oz-moh-la-riti) n.

the osmotic pressure of a substance expressed in terms of osmoles of substance per kg of solution.

Back  -    New Search

osmole (oz-mohl) n.

a unit of osmotic pressure equal to the molecular weight of a solute in grams divided by the number of ions or other particles into which it dissociates in solution.

Back  -    New Search

osmoreceptor (oz-moh-ri-sep-ter) n.

a group of cells in the hypothalamus that monitor blood concentration.

Back  -    New Search

osmosis (oz-moh-sis) n.

the passage of a solvent from a less concentrated to a more concentrated solution through a semipermeable membrane. In living organisms, the process of osmosis plays an important role in controlling the distribution of water.
—osmotic (oz-mot-ik) adj.

Back  -    New Search

osmotic pressure n.

the pressure by which water is drawn into a solution through a semipermeable membrane; the more concentrated the solution, the greater its osmotic pressure.

Back  -    New Search

osseointegration (oss-i-oh-in-ti-gray-shn) n.

the process by which certain materials, such as titanium, may be introduced into living bone without producing a foreign-body reaction. This allows a very tight and strong joint between the two structures.
Osseointegration is used, for example, to fix some dental implants and bone-anchored hearing aids.

Back  -    New Search

osseous (oss-is) adj.

bony: applied to the bony parts of the inner ear.

Back  -    New Search

ossicle (oss-i-kl) n.

a small bone. auditory o. any of the three small bones (the incus, malleus, and stapes) in the middle ear.

Back  -    New Search

ossification (osteogenesis) (oss-i-fi-kay-shn) n.

the formation of bone, which takes place in three stages by the action of osteoblasts. A meshwork of collagen fibres is deposited in connective tissue, followed by the production of a cementing polysaccharide. Finally the cement is impregnated with minute crystals of calcium salts. The osteoblasts become enclosed within the matrix as osteocytes.

Back  -    New Search

ost- (oste-, osteo-) prefix

denoting bone.

Back  -    New Search

ostectomy (oss-tek-tmi) n.

the surgical removal of a bone or a piece of bone. See also OSTEOTOMY.

Back  -    New Search

osteitis (osti-I-tis) n.

inflammation of bone, due to infection, damage, or metabolic disorder. o. deformans see PAGET'S DISEASE. o. fibrosa cystica the characteristic cystic changes that occur in bones during long-standing hyperparathyroidism.

Back  -    New Search

osteo-prefix

see OST-.

Back  -    New Search

osteoarthritis (osteoarthrosis) (osti-oh-arth-ry-tis) n.

a degenerative disease of joints resulting from wear of the articular cartilage, which may lead to secondary changes in the underlying bone. The joints are painful and stiff, with restricted movement. The condition may be primary or may result from abnormal load to the joint or damage to the cartilage from inflammation or trauma. Treatment consists of analgesics, reducing the load to the joint (e.g. by weight loss), or surgery (osteotomy, arthrodesis, or arthroplasty).

Back  -    New Search

osteoarthropathy (osti-oh-arth-rop--thi) n.

any disease of the bone and cartilage adjoining a joint.

Back  -    New Search

osteoarthrosis (osti-oh-arth-roh-sis) n.

see OSTEOARTHRITIS.

Back  -    New Search

osteoarthrotomy (osti-oh-arth-rot-mi) n.

surgical excision of the bone adjoining a joint.

Back  -    New Search

osteoblast (oss-ti-oh-blast) n.

a cell, originating in the mesoderm of the embryo, that is responsible for the formation of bone. See also OSSIFICATION.

Back  -    New Search

osteochondritis (osti-oh-kon-dry-tis) n.

1 necrosis of a bone due to interruption of its blood supply, which causes it to fragment and collapse before undergoing revascularization. See KIENBOCK'S DISEASE,KÖHLER'S DISEASE,LEGG-CALVÉ-PERTHES DISEASE.

2 inflammation of an apophysis from the pull of the attached tendon. See OSGOOD-SCHLATTER DISEASE, SEVER'S DISEASE. o. dissecans separation of a small fragment (or fragments) of bone and cartilage from the surface of a joint, most frequently the knee, with resulting pain, swelling, and limitation of movement.
Top

Back  -    New Search

osteochondroma (osti-oh-kon-droh-m) n. (pl. osteochondromata)

a bone tumour composed of cartilage-forming cells. It appears as a painless mass, usually at the end of a long bone. As a small proportion of these tumours become malignant if untreated, they are excised.

Back  -    New Search

osteochondrosis (osti-oh-kon-droh-sis) n.

see OSTEOCHONDRITIS.

Back  -    New Search

osteoclasia (osteoclasis) (osti-oh-klay-zi) n.

1 the deliberate breaking of a malformed or malunited bone, carried out by a surgeon to correct deformity. Also called: osteoclasty .

2 see OSTEOLYSIS.
Top

Back  -    New Search

osteoclasis (osti-ok-l-sis) n.

1 remodelling of bone by osteoclasts, during growth or the healing of a fracture.

2 see OSTEOCLASIA.
Top

Back  -    New Search

osteoclast (oss-ti-oh-klast) n.

1 a large multinucleate cell that resorbs calcified bone.

2 a device for fracturing bone for therapeutic purposes.
Top

Back  -    New Search

osteoclastoma (osti-oh-klas-toh-m) n.

a rare tumour of bone, caused by proliferation of osteoclast cells.

Back  -    New Search

osteocyte (oss-ti-oh-syt) n.

a bone cell. See also OSSIFICATION.

Back  -    New Search

osteodystrophy (osti-oh-dis-tr-fi) n.

any generalized bone disease resulting from a metabolic disorder.

Back  -    New Search

osteogenesis (osti-oh-jen-i-sis) n.

see OSSIFICATION. o. imperfecta (fragilitas ossium ) a congenital disorder in which the bones are unusually brittle and fragile.

Back  -    New Search

osteogenic (osti-oh-jen-ik) adj.

originating in or composed of bone tissue. o. sarcoma see OSTEOSARCOMA.

Back  -    New Search

osteology (osti-ol-ji) n.

the study of the structure and function of bones and related structures.

Back  -    New Search

osteolysis (osteoclasia) (osti-ol-i-sis) n.

dissolution of bone through disease, commonly by infection or loss of the blood supply (ischaemia) to the bone.
—osteolytic adj.

Back  -    New Search

osteoma (osti-oh-m) n.

a benign bone tumour. cancellous o. (exostosis) an outgrowth from the end of a long bone, usually rising to a point. compact o. (ivory tumour ) an osteoma that is usually harmless but may rarely compress surrounding structures, as within the skull. osteoid o. an overgrowth of bone-forming cells, usually causing pain in the middle of a long bone.

Back  -    New Search

osteomalacia (osti-oh-m-lay-shi) n.

softening of the bones caused by a deficiency of vitamin D, which leads to progressive decalcification of bony tissues, often causing bone pain. The condition may become irreversible if treatment with vitamin D is not given.

Back  -    New Search

osteomyelitis (osti-oh-my--ly-tis) n.

inflammation of bone due to infection. It can cause fracture and deformity of the bone. acute o. osteomyelitis occurring when bacteria enter the bone via the bloodstream; it is more common in children. There is severe pain and redness over the involved bone, accompanied by general illness and high fever. chronic o. osteomyelitis that may develop from partially treated acute osteomyelitis or after open fractures or surgery during which the bone is contaminated.

Back  -    New Search

osteopathy (osti-op--thi) n.

a system of diagnosis and treatment based on the theory that many diseases are associated with disorders of the musculoskeletal system. Diagnosis and treatment of these disorders involves palpation, manipulation, and massage. Osteopathy provides relief for many disorders of bones and joints.
—osteopath (ost-i--path) n.—osteopathic (osti--path-ik) adj.

Back  -    New Search

osteopetrosis (Albers-Schönberg disease, marble-bone disease) (osti-oh-pi-troh-sis) n.

a congenital abnormality in which bones become abnormally dense and brittle and tend to fracture. See also OSTEOSCLEROSIS.

Back  -    New Search

osteophony (osti-off-ni) n.

the conduction of sound by bone, such as occurs in the ossicles of the middle ear.

Back  -    New Search

osteophyte (oss-ti--fyt) n.

a projection of bone, usually shaped like a rose thorn, that occurs at sites of cartilage degeneration or destruction near joints and intervertebral discs.

Back  -    New Search

osteoplasty (oss-ti--plasti) n.

plastic surgery of bones.

Back  -    New Search

osteoporosis (osti-oh-por-oh-sis) n.

loss of bony tissue, resulting in bones that are brittle and liable to fracture. Infection, injury, and synovitis can cause localized osteoporosis. Generalized osteoporosis is common in the elderly, and in women often follows the menopause. Hormone replacement therapy is preventative, and biphosphonates can reduce or halt further bone loss.

Back  -    New Search

osteosarcoma (osteogenic sarcoma) (osti-oh-sar-koh-m) n.

a malignant bone tumour. In children the usual site for the tumour is the leg, particularly the femur. Secondary growths (metastases) are common, most frequently in the lungs (though other sites, such as the liver, may also be involved). Treatment of disease localized to the primary site was traditionally by amputation of the limb; limb-sparing surgery is now possible with replacement of the diseased bone by a metal prosthesis.

Back  -    New Search

osteosclerosis (osti-oh-skleer-oh-sis) n.

an abnormal increase in the density of bone, as a result of poor blood supply, chronic infection, or tumour. See also OSTEOPETROSIS.

Back  -    New Search

osteotome (oss-ti--tohm) n.

a surgical chisel designed to cut bone.

Back  -    New Search

osteotomy (osti-ot-mi) n.

a surgical operation to cut a bone into two parts, followed by realignment of the ends to allow healing. The operation may be performed to reduce pain and disability in an arthritic joint.

Back  -    New Search

ostium (oss-tim) n. (pl. ostia)

(in anatomy) an opening. o. abdominale the opening of the Fallopian tube into the abdominal cavity.

Back  -    New Search

-ostomy suffix.

see -STOMY.

Back  -    New Search

ot- (oto-) prefix

denoting the ear.

Back  -    New Search

otalgia (oh-tal-ji) n.

pain in the ear.

Back  -    New Search

OTC drug n.

see OVER-THE-COUNTER DRUG.

Back  -    New Search

otic (oh-tik) adj.

relating to the ear.

Back  -    New Search

otitis (oh-ty-tis) n.

inflammation of the ear. o. externa inflammation of the canal between the eardrum and the external opening of the ear. o. interna (labyrinthitis) inflammation of the inner ear causing vertigo, vomiting, loss of balance, and deafness. o. media acute or chronic inflammation of the middle ear. Acute inflammation, usually due to bacterial or viral infection, causes pain and a high fever; treatment is usually with antibiotics. Chronic inflammation is associated with perforations of the eardrum; treatment involves surgical repair. secretory o. media see GLUE EAR.

Back  -    New Search

otoconium (oh-toh-koh-nim) n.

see OTOLITH.

Back  -    New Search

otolaryngology (oh-toh-la-ring-ol-ji) n.

the study of diseases of the ears and larynx.
—otolaryngologist n.

Back  -    New Search

otolith (otoconium) (oh-toh-lith) n.

one of the small particles of calcium carbonate associated with a macula in the saccule or utricle of the inner ear.

Back  -    New Search

otology (oh-tol-ji) n.

the study of diseases of the ear.
—otologist n.

Back  -    New Search

-otomy suffix.

see -TOMY.

Back  -    New Search

otomycosis (oh-toh-my-koh-sis) n.

a fungus infection of the ear, causing irritation and inflammation of the canal between the eardrum and the external opening of the ear.

Back  -    New Search

otoplasty (pinnaplasty) (oh-toh-plasti) n.

surgical repair or reconstruction of the ears after injury or in the correction of a congenital defect.

Back  -    New Search

otorhinolaryngology (oh-toh-ry-noh-la-ring-ol-ji) n.

the study of ear, nose, and throat diseases (i.e. ENT disorders).
—otorhinolaryngologist n.

Back  -    New Search

otorrhagia (oh-toh-ray-ji) n.

bleeding from the ear.

Back  -    New Search

otorrhoea (oh-toh-ree-) n.

any discharge from the ear, commonly a purulent discharge in chronic middle ear infection (otitis media).

Back  -    New Search

otosclerosis (otospongiosis) (oh-toh-skleer-oh-sis) n.

a disorder causing deafness in adult life. An overgrowth of the bone of the inner ear leads to the stapes becoming fixed to the fenestra ovalis, so that sounds cannot be conducted to the inner ear.

Back  -    New Search

otoscope (oh-toh-skohp) n.

see AURISCOPE.

Back  -    New Search

otospongiosis (oh-toh-spunji-oh-sis) n.

see OTOSCLEROSIS.

Back  -    New Search

ototoxic (oh-toh-toks-ik) adj.

having a toxic effect on the organs of balance or hearing in the inner ear or on the vestibulocochlear nerve. Ototoxic drugs may be used in the treatment of Ménière's disease.

Back  -    New Search

ouabain (wah-bah-in) n.

a drug that stimulates the heart and is used to treat heart failure and other heart conditions. It is administered by mouth or injection and has the same actions and side-effects as digitalis.

Back  -    New Search

outbreeding (owt-breed-ing) n.

the production of offspring by parents who are not closely related. Compare INBREEDING.

Back  -    New Search

outer ear (owt-er) n.

the pinna and the external auditory meatus of the ear.

Back  -    New Search

out-of-the-body experience n.

a form of derealization in which there is a sensation of leaving one's body and visions of travelling through tunnels into light or of journeys on another plane of existence. It typically occurs after anaesthesia or severe illness and is often attributed to anoxia of the brain.

Back  -    New Search

out-patient (owt-pay-shnt) n.

a patient who receives treatment at a hospital but is not admitted to a bed in a hospital ward. Large hospitals have clinics at which out-patients can be given specialist treatment. Compare IN-PATIENT.

Back  -    New Search

oval window (oh-vl) n.

see FENESTRA (OVALIS).

Back  -    New Search

ovari- (ovario-) prefix

denoting the ovary.

Back  -    New Search

ovarian cancer (oh-vair-in) n.

a malignant tumour of the ovary, usually a carcinoma. The incidence of the disease reaches a peak in postmenopausal women; treatment involves surgery and most cases also require combined chemotherapy and/or radiotherapy.

Back  -    New Search

ovarian cyst n.

a fluid-filled sac, one or more of which may develop in the ovary. Although most ovarian cysts are not malignant, they may reach a very large size and rotate on their stalks, thus cutting off their blood supply and causing severe abdominal pain and vomiting; in such cases the cysts require urgent surgical removal.

Back  -    New Search

ovariectomy (oh-vair-i-ek-tmi) n.

see OOPHORECTOMY.

Back  -    New Search

ovariotomy (oh-vair-i-ot-mi) n.

literally, incision of an ovary. However, the term commonly refers to surgical removal of an ovary (oophorectomy).

Back  -    New Search

ovaritis (oh-v-ry-tis) n.

see OOPHORITIS.

Back  -    New Search

ovary (oh-ver-i) n.

the main female reproductive organ, which contains follicles that produce ova and steroid hormones in a regular cycle (see MENSTRUAL CYCLE). There are two ovaries, situated in the lower abdomen, one on each side of the uterus (see REPRODUCTIVE SYSTEM).
—ovarian adj.

Back  -    New Search

overcompensation (oh-ver-kom-pen-say-shn) n.

(in psychology) the situation in which a person tries to overcome a disability by making greater efforts than are required.

Back  -    New Search

overt (oh-vert) adj.

plainly to be seen or detected: applied to diseases with observable signs and symptoms.

Back  -    New Search

over-the-counter (OTC) drug (oh-ver-th-kownt-er) n.

a drug that may be purchased directly from a pharmacist without a doctor's prescription. Current government policy is to extend the range of OTC drugs: a number have already been derestricted (e.g. ibuprofen) and this trend is expected to increase.

Back  -    New Search

ovi (ovo-) prefix

denoting an egg; ovum.

Back  -    New Search

oviduct (oh-vi-dukt) n.

see FALLOPIAN TUBE.

Back  -    New Search

ovulation (ov-yoo-lay-shn) n.

the process by which an ovum is released from a mature Graafian follicle. The fluid-filled follicle distends the surface of the ovary until a thin spot breaks down and the ovum floats out and starts to travel down the Fallopian tube to the uterus.

Back  -    New Search

ovum (egg cell) (oh-vm) n. (pl. ova)

the mature female sex cell (see GAMETE).

Back  -    New Search

oxalate (oks--layt) n.

a salt of oxalic acid. balanced o. a mixture of ammonium and potassium oxalates (an anticoagulant) in which blood specimens are stored before laboratory examination.

Back  -    New Search

oxalic acid (oks-al-ik) n.

an extremely poisonous acid found in many plants, including sorrel and the leaves of rhubarb, and in some bleaching powders. When swallowed it produces burning sensations in the mouth and throat, vomiting of blood, breathing difficulties, and circulatory collapse. Treatment is with calcium lactate or other calcium salts, lime water, or milk. Formula:
C_2H_2O_4
.

Back  -    New Search

oxaluria (oks-l-yoor-i) n.

the presence in the urine of oxalic acid or oxalates, especially calcium oxalate.

Back  -    New Search

oxatomide (oks-at--myd) n.

an antihistamine drug used to treat hay fever. It is administered by mouth. Trade name: Tinset .

Back  -    New Search

oxazepam (oks-az--pam) n.

a benzodiazepine drug administered by mouth to relieve anxiety and tension and for the treatment of alcoholism.

Back  -    New Search

oxidant (oks-i-dnt) n.

(in biological systems) a molecule that serves as an electron acceptor. In human disease oxidants are derived from normal intracellular processes and released by inflammatory cells. They are counteracted by antioxidants, such as beta-carotene.

Back  -    New Search

oxidase (oks-i-dayz) n.

see OXIDOREDUCTASE.

Back  -    New Search

oxidation (oks-i-day-shn) n.

a reaction in which an atom or molecule loses electrons. Many biological oxidations are effected by the removal of hydrogen atoms, which combine with an oxidizing agent . For example, glucose is oxidized during cellular respiration: C_6H_12O_6 + 6O_2 6CO_2 + 6H_2O.

Back  -    New Search

oxidoreductase (oks-i-doh-ri-duk-tayz) n.

one of a group of enzymes that catalyse oxidation-reduction reactions. This class includes the enzymes formerly known either as dehydrogenases or as oxidases .

Back  -    New Search

oximeter (oks-im-it-er) n.

an instrument for measuring the proportion of oxyhaemoglobin in the blood.

Back  -    New Search

oxprenolol (oks-pren--lol) n.

a drug that controls the activity of the heart (see BETA BLOCKER), administered by mouth or injection to treat angina, high blood pressure, and abnormal heart rhythm. Trade name: Trasicor .

Back  -    New Search

oxybutinin (oksi-bew-tin-in) n.

a drug administered orally to reduce frequency and urgency of passing urine associated with an unstable bladder or instability of the detrusor muscle of the bladder wall.

Back  -    New Search

oxycephaly (turricephaly) (oksi-sef-li) n.

a deformity of the bones of the skull giving the head a pointed appearance. See also CRANIOSYNOSTOSIS.
—oxycephalic (oksi-si-fal-ik) adj.

Back  -    New Search

oxygen (oks-i-jn) n.

an odourless colourless gas that makes up one-fifth of the atmosphere. Oxygen is essential to most forms of life; in man, it is absorbed into the blood from air breathed into the lungs. Oxygen is administered therapeutically in various conditions in which the tissues are unable to obtain an adequate supply through the lungs. Symbol: O. o. deficit a physiological condition that exists in cells during periods of temporary oxygen shortage. o. tent see TENT.

Back  -    New Search

oxygenation (oksi-ji-nay-shn) n.

the process of becoming saturated with oxygen, such as occurs in the lungs during inhalation of air.

Back  -    New Search

oxygenator (oks-i-ji-nay-ter) n.

a machine that oxygenates blood outside the body. See also HEART-LUNG MACHINE.

Back  -    New Search

oxyhaemoglobin (oksi-hee-moh-gloh-bin) n.

the bright-red substance formed when the pigment haemoglobin in red blood cells combines reversibly with oxygen. Oxyhaemoglobin is the form in which oxygen is transported from the lungs to the tissues. Compare METHAEMOGLOBIN.

Back  -    New Search

oxymetazoline (oksi-met-az-oh-leen) n.

a sympathomimetic drug administered as a nasal spray to treat nasal congestion. Trade name: Afrazine .

Back  -    New Search

oxyntic cells (parietal cells) (oks-in-tik) pl. n.

cells of the gastric glands that secrete hydrochloric acid in the fundic region of the stomach.

Back  -    New Search

oxytetracycline (oksi-tet-r-sy-kleen) n.

an antibiotic used to treat infections caused by a wide variety of bacteria. It is administered by mouth or injection or applied to the skin in a cream. Trade names: Imperacin , Terramycin .

Back  -    New Search

oxytocic (oksi-toh-sik) n.

any agent that induces or accelerates labour by stimulating the muscles of the uterus to contract. See also OXYTOCIN.

Back  -    New Search

oxytocin (oksi-toh-sin) n.

a hormone, released by the pituitary gland, that causes contraction of the uterus during labour and stimulates milk flow from the breasts by causing contraction of muscle fibres in the milk ducts. Pituitary extract (Syntocinon) is used to induce uterine contractions and to control or prevent postpartum haemorrhage.

Back  -    New Search

oxyuriasis (oksi-yoor-I--sis) n.

see ENTEROBIASIS.

Back  -    New Search

Oxyuris (oksi-yoor-iss) n.

see THREADWORM.

Back  -    New Search

ozaena (oh-zee-n) n.

a disorder of the nose in which the mucous membranes inside the nose become atrophied, with the production of an offensive discharge and crusts.

Back  -    New Search

ozone (oh-zohn) n.

a poisonous gas containing three oxygen atoms per molecule. Ozone is a very powerful oxidizing agent. It is found in the atmosphere at very high altitudes (the ozone layer ) and is responsible for absorbing a large proportion of the sun's ultraviolet radiation.

Back  -    New Search

P

P

symbol for phosphorus.

Back  -    New Search

Pacchionian body (pak-i-oh-ni-n) n.

see ARACHNOID. [A. Pacchioni (1665–1726), Italian anatomist]

Back  -    New Search

pacemaker (payss-mayk-er) n.

1 a device used to produce and maintain a normal heart rate in patients who have heart block. It consists of a battery that stimulates the heart through an insulated electrode wire attached to the surface of the ventricle (epicardial p. ) or lying in contact with the lining of the heart (endocardial p. ). A pacemaker may be temporary, with an external battery, or it may be permanent, when the whole apparatus is surgically implanted under the skin.

2 the part of the heart that regulates the rate at which it beats: the sinoatrial node.
Top

Back  -    New Search

pachy- prefix

denoting 1 thickening of a part or parts.

2 the dura mater.
Top

Back  -    New Search

pachydactyly (pak-i-dak-tili) n.

abnormal enlargement of the fingers and toes, occurring either as a congenital abnormality or as part of an acquired disease (such as acromegaly).

Back  -    New Search

pachymeningitis (pak-i-men-in-jy-tis) n.

inflammation of the dura mater (see MENINGITIS).

Back  -    New Search

pachymeninx (pak-i-mee-ninks) n.

the dura mater, outermost of the three meninges.

Back  -    New Search

pachymeter (pak-im-it-er) n.

an instrument used to measure the thickness of the cornea.
—pachymetry n.

Back  -    New Search

pachysomia (pak-i-soh-mi) n.

thickening of parts of the body, which occurs in certain diseases.

Back  -    New Search

Pacinian corpuscles (p-sin-in) pl. n.

sensory receptors for touch in the skin, consisting of sensory nerve endings surrounded by capsules of membrane. They are especially sensitive to changes in pressure and so detect vibration particularly well. [F. Pacini (1812–83), Italian anatomist]

Back  -    New Search

pack (pak) n.

a pad of folded moistened material, such as cotton-wool, applied to the body or inserted into a cavity.

Back  -    New Search

packed cell volume (haematocrit) n.

the volume of the red cells (erythrocytes) in blood, expressed as a fraction of the total volume of the blood.

Back  -    New Search

paclitaxel (pak-li-taks-l) n.

a cytotoxic anticancer drug that exercises control on the growth of certain cancers.
Administered by intravenous infusion, it is used to treat ovarian and breast cancers that are resistant to standard therapies. Trade name: Taxol .

Back  -    New Search

PACS n.

picture archiving and communication system: an electronic system enabling the storage of X-ray and other images digitally on computer disk, for later retrieval and subsequent display on high-resolution monitors, via computer links (digital networks), at local or distant sites (see DIGITIZATION).

Back  -    New Search

pad (pad) n.

cotton-wool, foam rubber, or other material used to protect a part of the body from friction, bruising, or other unwanted contact.

Back  -    New Search

paed- (paedo-) prefix

denoting children.

Back  -    New Search

paediatrics (peed-i-at-riks) n.

the general medicine of childhood. Handling the sick child requires detailed knowledge of genetics, obstetrics, psychological development, management of handicaps at home and in school, and effects of social conditions on child health. See also CHILD HEALTH CLINIC.
—paediatric adj. —paediatrician (peed-i--trish-n) n.

Back  -    New Search

Paget's disease (paj-its) n.

1 a chronic disease of bones, occurring in the elderly and most frequently affecting the skull, backbone, pelvis, and long bones; affected bones become thickened. There are often no symptoms, but pain, deformity, and fracture can occur. Medical name: osteitis deformans .

2 a malignant condition of the nipple, resembling eczema in appearance, that is associated with underlying infiltrating cancer of the breast. [Sir J. Paget (1814–99), British surgeon]
Top

Back  -    New Search

pain clinic (payn) n.

a clinic that specializes in techniques of long-term pain relief, such as transcutaneous electrical nerve stimulation (TENS). Pain clinics are usually directed by anaesthetists.

Back  -    New Search

paint (paynt) n.

(in pharmacy) a liquid preparation that is applied to the skin or mucous membranes. Paints usually contain antiseptics, astringents, caustics, or analgesics.

Back  -    New Search

palaeo- prefix

denoting 1 ancient.

2 primitive.
Top

Back  -    New Search

palate (pal-t) n.

the roof of the mouth, which separates the mouth from the nasal cavity. hard p. the front part of the palate. It is formed by processes of the maxillae and palatine bones and is covered by mucous membrane. soft p. the posterior part of the palate: a movable fold of mucous membrane that tapers at the back of the mouth to form the uvula. See also CLEFT PALATE.

Back  -    New Search

palatine bone (pal--tyn) n.

either of a pair of approximately L-shaped bones of the face that contribute to the hard palate, the nasal cavity, and the orbits.

Back  -    New Search

palato- prefix

denoting 1 the palate.

2 the palatine bone.
Top

Back  -    New Search

palatoplasty (pal-a-toh-plasti) n.

plastic surgery of the roof of the mouth, usually to correct cleft palate or other congenital defects. laser p. laser surgery to shorten and/or stiffen the palate in the treatment of snoring.

Back  -    New Search

palatoplegia (pal--toh-plee-ji) n.

paralysis of the soft palate.

Back  -    New Search

palatorrhaphy (pal-t-o-rfi) n.

see STAPHYLORRHAPHY.

Back  -    New Search

pali- (palin-) prefix

denoting repetition or recurrence.

Back  -    New Search

palilalia (pal-i-lay-li) n.

a disorder of speech in which a word spoken by the individual is rapidly and involuntarily repeated.

Back  -    New Search

palindromic (pal-in-drom-ik) adj.

relapsing: describing diseases or symptoms that recur or get worse.

Back  -    New Search

palliative (pal-i-tiv) n.

a medicine that gives temporary relief from the symptoms of a disease but does not actually cure the disease.

Back  -    New Search

pallidectomy (pallidotomy) (pal-i-dek-tmi) n.

a neurosurgical operation to destroy or modify the effects of the globus pallidus (see BASAL GANGLIA) for the relief of parkinsonism and other conditions in which involuntary movements are prominent.

Back  -    New Search

pallidotomy (pal-i-dot-mi) n.

see PALLIDECTOMY.

Back  -    New Search

pallor (pal-er) n.

abnormal paleness of the skin, due to reduced blood flow or lack of normal pigments. Pallor may indicate shock, anaemia, cancer, or other diseases.

Back  -    New Search

palmar (pal-mer) adj.

relating to the palm of the hand. p. arches two arterial arches (deep and superficial) in the palm of the hand, formed by anastomosis of the ulnar and radial arteries.

Back  -    New Search

palmitic acid (pal-mit-ik) n.

see FATTY ACID.

Back  -    New Search

palpation (pal-pay-shn) n.

the process of examining part of the body by careful feeling with the hands and fingertips.

Back  -    New Search

palpebral (pal-pi-brl) adj.

relating to the eyelid (palpebra ).

Back  -    New Search

palpitation (pal-pi-tay-shn) n.

an awareness of the heartbeat. This is normal with fear, emotion, or exertion. It may also be a symptom of neurosis, arrhythmias, heart disease, and overactivity of the circulation.

Back  -    New Search

palsy (pawl-zi) n.

paralysis. See BELL'S PALSY, CEREBRAL PALSY.

Back  -    New Search

paludism (pal-yoo-dizm) n.

see MALARIA.

Back  -    New Search

pamidronate (pam-i-droh-nayt) n.

see BIPHOSPHONATES.

Back  -    New Search

pan- (pant(o)-) prefix

denoting all; every: hence (in medicine) affecting all parts of an organ or the body; generalized.

Back  -    New Search

panacea (pan--see-) n.

a medicine said to be a cure for all diseases and disorders. Unfortunately panaceas do not exist, despite the claims of many patent medicine manufacturers.

Back  -    New Search

Panadol (pan--dol) n.

see PARACETAMOL.

Back  -    New Search

panarthritis (pan-arth-ry-tis) n.

inflammation of all the structures involved in a joint. See ARTHRITIS.

Back  -    New Search

pancarditis (pan-kar-dy-tis) n.

an inflammatory disorder affecting the pericardium, endocardium, and heart muscle.

Back  -    New Search

Pancoast syndrome (pan-kohst) n.

pain and paralysis involving the lower branches of the brachial plexus due to infiltration by a malignant tumour of the apical region of the lung. Horner's syndrome may also be present. [H. K. Pancoast (1875–1939), US radiologist]

Back  -    New Search

pancreas (pank-ri-s) n.

a compound gland, about 15 cm long, that lies behind the stomach. One end lies in the curve of the duodenum; the other end touches the spleen. It is composed of clusters (acini) of cells that secrete pancreatic juice into the duodenum via the pancreatic duct , which unites with the common bile duct. Interspersed among the acini are the islets of Langerhans, which secrete the hormones insulin and glucagon into the bloodstream.
—pancreatic (pank-ri-at-ik) adj.

Back  -    New Search

pancreatectomy (pank-ri--tek-tmi) n.

surgical removal of the pancreas, performed for tumours in the gland or because of chronic or relapsing pancreatitis. partial p. removal of a portion of the gland. subtotal p. removal of most of the gland. total p. (Whipple's operation ) removal of the entire gland and part of the duodenum.

Back  -    New Search

pancreatic juice n.

the mixture of digestive enzymes secreted by the pancreas. Its production is stimulated by hormones secreted by the duodenum (see CHOLECYSTOKININ, SECRETIN).

Back  -    New Search

pancreatin (pank-ri--tin) n.

an extract obtained from the pancreas, containing the pancreatic enzymes. Pancreatin is administered to treat conditions in which pancreatic secretion is deficient; for example, in pancreatitis.

Back  -    New Search

pancreatitis (pank-ri--ty-tis) n.

inflammation of the pancreas. acute p. a sudden illness in which the patient experiences severe pain in the upper abdomen and back, with shock. Treatment consists of intravenous feeding and anticholinergic drugs. chronic p. pancreatitis that may produce symptoms similar to relapsing pancreatitis or may be painless; it leads to pancreatic failure causing malabsorption and diabetes mellitus. relapsing p. pancreatitis in which the symptoms of acute pancreatitis are recurrent and less severe. It may be associated with gallstones or with alcoholism.

Back  -    New Search

pancreatotomy (pank-ri--tot-mi) n.

surgical opening of the duct of the pancreas in order to inspect the duct, to join the duct to the intestine, or to inject a contrast medium.

Back  -    New Search

pancreozymin (pank-ri-oh-zy-min) n.

the name originally given to the fraction of the hormone cholecystokinin that acts on the pancreas.

Back  -    New Search

pancytopenia (pan-sy-toh-pee-ni) n.

a simultaneous decrease in the numbers of red cells, white cells, and platelets in the blood. It occurs in a variety of disorders, including aplastic anaemias, hypersplenism, and tumours of the bone marrow.

Back  -    New Search

pandemic (pan-dem-ik) n.

an epidemic so widely spread that vast numbers of people in different countries are affected.
—pandemic adj.

Back  -    New Search

panic disorder (pan-ik) n.

a condition featuring recurrent panic attacks : brief episodes of acute distress in which the heart beats rapidly, breathing is deep and fast, and sweating occurs. The attacks are especially common in people with agoraphobia. The condition appears to be an organic disorder with a strong psychological component.

Back  -    New Search

panniculitis (p-nik-yoo-ly-tis) n.

inflammation of the panniculus adiposus, leading to multiple tender nodules in the legs and trunk.

Back  -    New Search

panniculus (p-nik-yoo-ls) n.

a membranous sheet of tissue. p. adiposus the fatty layer of tissue underlying the skin.

Back  -    New Search

pannus (pan-s) n.

invasion of the outer layers of the cornea of the eye by tissue containing many blood vessels, which grows in from the conjunctiva.

Back  -    New Search

panophthalmitis (pan-off-thal-my-tis) n.

inflammation involving the whole of the interior of the eye.

Back  -    New Search

panosteitis (pan-osti-I-tis) n.

inflammation of all the structures of a bone.

Back  -    New Search

panotitis (pan--ty-tis) n.

inflammation of both the middle and the inner ears.

Back  -    New Search

pant- (panto-) prefix.

see PAN-.

Back  -    New Search

pantothenic acid (pan-t-theen-ik) n.

a B vitamin that is a constituent of coenzyme A. It plays an important role in the transfer of acetyl groups in the body.

Back  -    New Search

pantropic (pan-trop-ik) adj.

describing a virus that can invade and affect many different tissues of the body without showing a special affinity for any one of them.

Back  -    New Search

Papanicolaou test (Pap test) (pap--nik-oh-lay-oo) n.

a test to detect cancer of the cervix or lining of the uterus. See also CERVICAL SMEAR. [G. N. Papanicolaou (1883–1962), Greek physician, anatomist, and cytologist]

Back  -    New Search

papaveretum (p-pav-er-ee-tm) n.

a preparation of opium used for the relief of pain. It also contains several opium alkaloids, including papaverine.

Back  -    New Search

papaverine (p-pav-er-een) n.

an alkaloid, derived from opium, that relaxes smooth muscle. It is administered by injection as a preanaesthetic medication, usually in conjunction with morphine.

Back  -    New Search

papilla (p-pil-) n. (pl. papillae)

any small nipple-shaped protuberance. Several different kinds of papillae occur on the tongue, in association with the taste buds. optic p. see OPTIC (DISC).
—papillary adj.

Back  -    New Search

papillitis (pap-i-ly-tis) n.

inflammation of the optic disc.

Back  -    New Search

papilloedema (pap-il-ee-dee-m) n.

swelling of the optic disc.

Back  -    New Search

papilloma (pap-i-loh-m) n.

a benign nipple-like growth on the surface of skin or mucous membrane. basal-cell p. see (SEBORRHOEIC) KERATOSIS.
—papillomatous adj.

Back  -    New Search

papillomatosis (pap-i-loh-m-toh-sis) n.

a condition in which many papillomas grow on an area of skin or mucous membrane.

Back  -    New Search

papillotomy (pap-i-lot-mi) n.

the operation of cutting the ampulla of Vater to widen its outlet in order to improve bile drainage and allow the passage of stones from the common bile duct. It is usually performed using a diathermy wire through a duodenoscope following ERCP.

Back  -    New Search

papovavirus (pap-oh-v-vy-rs) n.

one of a group of small DNA-containing viruses producing tumours in animals and man.

Back  -    New Search

Pap test (pap) n.

see PAPANICOLAOU TEST.

Back  -    New Search

papule (pap-yool) n.

a small raised spot on the skin.
—papular adj.

Back  -    New Search

papulo- prefix

denoting a papule or pimple.

Back  -    New Search

papulopustular (pap-yoo-loh-pus-tew-ler) adj.

describing a rash that contains both papules and pustules.

Back  -    New Search

papulosquamous (pap-yoo-loh-skway-ms) adj.

describing a rash that is both papular and scaly.

Back  -    New Search

para- prefix

denoting 1 beside or near.

2 resembling.
Top

3 abnormal.
Top

Back  -    New Search

para-aminobenzoic acid (pa-r--mee-no-ben-zoh-ik) n.

a naturally occurring drug used in lotions and creams to prevent sunburn.

Back  -    New Search

para-aminosalicylic acid (PAS) (pa-r--mee-noh-sal-i-sil-ik) n.

a drug administered by mouth, in conjunction with isoniazid or streptomycin, to treat tuberculosis. It is chemically related to aspirin.

Back  -    New Search

paracentesis (pa-r-sen-tee-sis) n.

tapping: the process of drawing off excess fluid from a part of the body through a hollow needle or cannula.

Back  -    New Search

paracetamol (acetaminophen) (pa-r-see-t-mol) n.

an analgesic drug that also reduces fever. It is administered by mouth to treat mild or moderate pain, such as headache, toothache, and rheumatism. Trade names: Calpol , Panadol , Panaleve .

Back  -    New Search

paracusis (pa-r-kew-sis) n.

any abnormality of hearing.

Back  -    New Search

paradoxical breathing (pa-r-doks-ikl) n.

breathing movements in which the chest wall moves in on inspiration and out on expiration, in reverse of the normal movements. It may be seen in children with respiratory distress and patients with chronic airways obstruction. Crush injuries of the chest can lead to a severe degree of paradoxical breathing.

Back  -    New Search

paraesthesiae (pa-ris-theez-i-ee) pl. n.

spontaneously occurring abnormal tingling sensations, sometimes described as pins and needles . Compare DYSAESTHESIAE.

Back  -    New Search

paraffin (pa-r-fin) n.

one of a series of hydrocarbons derived from petroleum. liquid p. a mineral oil, which has been used as a laxative. p. wax (hard p. ) a whitish mixture of solid hydrocarbons, used in medicine mainly as a base for ointments.

Back  -    New Search

parageusia (parageusis) (pa-r-gew-si) n.

abnormality of the sense of taste.

Back  -    New Search

paragonimiasis (endemic haemoptysis) (pa-r-gon-i-my--sis) n.

a tropical disease, occurring principally in the Far East, caused by the presence of the fluke Paragonimus westermani in the lungs. Symptoms include the coughing up of blood and dyspnoea.

Back  -    New Search

parainfluenza viruses (pa-r-in-floo-en-z) pl. n.

a group of large RNA-containing viruses that cause infections of the respiratory tract producing mild influenza-like symptoms. They are included in the paramyxovirus group (see MYXOVIRUS).

Back  -    New Search

paraldehyde (p-ral-di-hyd) n.

a hypnotic and anticonvulsant drug administered by mouth, injection, or in suppositories to induce sleep in mental patients and to control convulsions in tetanus.

Back  -    New Search

paralysis (p-ral-i-sis) n.

muscle weakness that varies in its extent, its severity, and the degree of spasticity or flaccidity according to the nature of the underlying disease and its distribution in the brain, spinal cord, peripheral nerves, or muscles. See also DIPLEGIA, HEMIPLEGIA, PARAPLEGIA, POLIOMYELITIS.
—paralytic (pa-r-lit-ik) adj.

Back  -    New Search

paramedian (pa-r-mee-di-n) adj.

situated close to or beside the median plane.

Back  -    New Search

paramedical (pa-r-med-ikl) adj.

describing or relating to the professions closely linked to the medical profession and working in conjunction with them. Paramedical personnel in a hospital include radiographers, physiotherapists, occupational therapists, and dietitians.

Back  -    New Search

paramesonephric duct (Müllerian duct) (pa-r-mes-oh-nef-rik) n.

either of a pair of ducts in the embryo that develop into the Fallopian tubes, uterus and part of the vagina.

Back  -    New Search

parameter (p-ram-it-er) n.

(in medicine) a measurement of some factor, such as blood pressure, pulse rate, or haemoglobin level, that may have a bearing on the condition being investigated.

Back  -    New Search

parametritis (pelvic cellulitis) (pa-r-mi-try-tis) n.

inflammation of the parametrium. The condition may be associated with puerperal infection.

Back  -    New Search

parametrium (pa-r-mee-trim) n.

the layer of connective tissue surrounding the uterus.

Back  -    New Search

paramnesia (pa-ram-nee-zi) n.

a distorted memory, such as confabulation or déjà vu.

Back  -    New Search

paramyotonia congenita (pa-r-my--toh-nia kn-jen-it-) n.

a rare constitutional disorder in which myotonia develops when the patient is exposed to cold. This may be due to a disorder of potassium metabolism.

Back  -    New Search

paramyxovirus (pa-r-miks-oh-vy-rs) n.

see MYXOVIRUS.

Back  -    New Search

paranasal sinuses (pa-r-nay-zl) pl. n.

the air-filled spaces, lined with mucous membrane, that occur in some bones of the skull and open into the nasal cavity. They comprise the frontal sinuses and the maxillary sinuses (one pair of each), the ethmoid sinuses (consisting of many spaces inside the ethmoid bone), and the two sphenoid sinuses .

Back  -    New Search

paraneoplastic syndrome (pa-r-nee-oh-plast-ik) n.

signs or symptoms that may occur in a patient with cancer but are not due directly to local effects of the cancer cells. Removal of the cancer usually leads to resolution of the problem. An example is myasthenia gravis secondary to a tumour of the thymus.

Back  -    New Search

paranoia (pa-r-noi-) n.

a mental disorder characterized by delusions organized into a system, without hallucinations or other marked symptoms of mental illness. The same term is sometimes used more loosely for a state of mind in which the individual has a strong belief that he is persecuted by others.

Back  -    New Search

paranoid (pa-r-noid) adj.

1 describing a mental state characterized by fixed and logically elaborated delusions. There are many causes, including paranoid schizophrenia, manic-depressive psychosis, and severe emotional stress.

2 describing a personality distinguished by such traits as excessive sensitivity to rejection by others, suspiciousness, hostility, and self-importance.
Top

Back  -    New Search

paraparesis (pa-r-p-ree-sis) n.

weakness of both legs, resulting from disease of the nervous system.

Back  -    New Search

paraphasia (pa-r-fay-zi) n.

a disorder of language in which unintended syllables, words, or phrases are interpolated in the patient's speech.

Back  -    New Search

paraphimosis (pa-r-fi-moh-sis) n.

retraction and constriction of the foreskin behind the glans penis. The tight foreskin cannot be drawn back over the glans and becomes painful and swollen.

Back  -    New Search

paraphrenia (pa-r-free-ni) n.

a mental disorder, typically seen in the elderly and deaf, that is characterized by systematic delusions and prominent hallucinations but without any other marked symptoms of mental illness. Some sufferers eventually show other symptoms of schizophrenia.

Back  -    New Search

paraplegia (pa-r-plee-ji) n.

paralysis of both legs, usually due to disease or injury of the spinal cord. It is often accompanied by loss of sensation below the level of the injury and disturbed bladder function.
—paraplegic adj., n.

Back  -    New Search

parapsoriasis (pa-r-s-ry--sis) n.

a former name for the earliest phase of mycosis fungoides.

Back  -    New Search

parapsychology (pa-r-sy-kol-ji) n.

the study of mental abilities that appear to defy natural law.

Back  -    New Search

Paraquat (pa-r-kwot) n.

Trademark. the chemical compound dimethyl dipyridilium, widely used as a weed-killer. When swallowed it exerts its most serious effects upon the lungs, the tissues of which it destroys after a few days.

Back  -    New Search

parasite (pa-r-syt) n.

any living thing that lives in or on another living organism (see HOST). Some parasites cause irritation and interfere with bodily functions; others destroy host tissues and release toxins into the body. Human parasites include fungi, bacteria, viruses, protozoa, and worms. See also COMMENSAL, SYMBIOSIS.
—parasitic (pa-r-sit-ik) adj.

Back  -    New Search

parasiticide (pa-r-sit-i-syd) n.

an agent that destroys parasites (excluding bacteria and fungi). See also ACARICIDE, ANTHELMINTIC, TRYPANOCIDE.

Back  -    New Search

parasitology (pa-r-sit-ol-ji) n.

the study and science of parasites.

Back  -    New Search

parasuicide (pa-r-soo-i-syd) n.

a self-injuring act (such as an overdose of sleeping pills) that is not motivated by a genuine wish to die. Compare (ATTEMPTED) SUICIDE.

Back  -    New Search

parasympathetic nervous system (pa-r-sim-p-thet-ik) n.

one of the two divisions of the autonomic nervous system, having fibres that leave the central nervous system from the brain and the lower portion of the spinal cord and are distributed to blood vessels, glands, and internal organs. The nerve endings release acetylcholine as a neurotransmitter.

Back  -    New Search

parasympatholytic (pa-r-sim-p-thoh-lit-ik) n.

a drug, such as atropine, that opposes the effects of the parasympathetic nervous system. The actions of parasympatholytic drugs include relaxation of smooth muscle, decreased secretion of saliva, sweat, and digestive juices, and dilation of the pupil of the eye.

Back  -    New Search

parasympathomimetic (pa-r-sim-p-thoh-mi-met-ik) n.

a drug that has the effect of stimulating the parasympathetic nervous system. The actions of the parasympathomimetic drugs include stimulation of skeletal muscle, vasodilatation, depression of heart rate, increasing the tension of smooth muscle, increasing secretions (such as saliva), and constricting the pupil of the eye.

Back  -    New Search

parathion (pa-r-th'y-on) n.

an organic phosphorus compound, used as a pesticide, that causes poisoning when inhaled, ingested, or absorbed through the skin. The symptoms are headache, sweating, salivation, lacrimation, vomiting, diarrhoea, and muscular spasms. Treatment is by administration of atropine.

Back  -    New Search

parathormone (pa-r-thor-mohn) n.

see PARATHYROID HORMONE.

Back  -    New Search

parathyroidectomy (pa-r-th'y-roid-ek-tmi) n.

surgical removal of the parathyroid glands, usually as part of the treatment of hyperparathyroidism.

Back  -    New Search

parathyroid glands (pa-r-th'y-roid) pl. n.

two pairs of yellowish-brown endocrine glands that are situated behind, or sometimes embedded within, the thyroid gland. They are stimulated to produce parathyroid hormone by a decrease in the amount of calcium in the blood.

Back  -    New Search

parathyroid hormone (parathormone) n.

a hormone, synthesized and released by the parathyroid glands, that controls the distribution of calcium and phosphate in the body. A deficiency of the hormone lowers blood calcium levels, causing tetany. Compare CALCITONIN.

Back  -    New Search

paratyphoid fever (pa-r-ty-foid) n.

an infectious disease caused by the bacterium Salmonella paratyphi A, B, or C. Symptoms include diarrhoea, mild fever, and a pink rash on the chest. Treatment with chloramphenicol is effective. Vaccination with TAB provides temporary immunity against paratyphoid A and B.

Back  -    New Search

paravertebral (pa-r-ver-tib-rl) adj.

close to or at the side of the backbone.

Back  -    New Search

parenchyma (p-renk-im-) n.

the functional part of an organ, as opposed to the supporting tissue (see STROMA).

Back  -    New Search

parenteral (pa-rent-er-l) adj.

administered by any way other than through the mouth: applied, for example, to the introduction of drugs into the body by injection.

Back  -    New Search

paresis (p-ree-sis) n.

muscular weakness caused by disease of the nervous system. It implies a lesser degree of weakness than paralysis, although the two words are often used interchangeably.

Back  -    New Search

paries (pair-i-eez) n. (pl. parietes)

1 the enveloping or surrounding part of an organ or other structure.

2 the wall of a cavity.
Top

Back  -    New Search

parietal (p-ry--t'l) adj.

of or relating to the inner walls of a body cavity, as opposed to the contents. p. bone either of a pair of bones forming the top and sides of the cranium. See SKULL. p. cells see OXYNTIC CELLS. p. lobe one of the major divisions of each cerebral hemisphere (see CEREBRUM), lying beneath the crown of the skull. It contains the sensory cortex and association areas. p. pleura see PLEURA.

Back  -    New Search

parity (pa-riti) n.

a term used to indicate the number of pregnancies a woman has had that have each resulted in the birth of an infant capable of survival. See also GRAND MULTIPARITY.

Back  -    New Search

parkinsonism (par-kin-sn-izm) n.

a clinical picture that is characterized by tremor, rigidity, and a poverty of spontaneous movements. The patient has an expressionless face, an unmodulated voice, an increasing tendency to stoop, and a shuffling walk. Parkinsonism is a disease process affecting the basal ganglia of the brain and associated with a deficiency of the neurotransmitter dopamine.
Sometimes a distinction is made between Parkinson's disease , a degenerative disorder associated with ageing, and parkinsonism due to other causes, notably the long-term use of antipsychotic drugs. Relief of the symptoms may be obtained with anticholinergic drugs and levodopa. [J. Parkinson (1755–1824), British physician]

Back  -    New Search

paromomycin (pa-roh-moh-my-sin) n.

an antibiotic, active against intestinal bacteria and amoebae, administered by mouth to treat dysentery.

Back  -    New Search

paronychia (whitlow) (pa-roh-nik-i) n.

an inflamed swelling of the nail folds. acute p. a condition that is usually caused by infection with Staphylococcus aureus. chronic p. paronychia that occurs mainly in those who habitually engage in wet work; it is associated with secondary infection with Candida albicans.

Back  -    New Search

parosmia (pa-roz-mi) n.

any disorder of the sense of smell.

Back  -    New Search

parotid gland (p-rot-id) n.

one of a pair of salivary glands situated in front of each ear.

Back  -    New Search

parotitis (pa-r-ty-tis) n.

inflammation of the parotid salivary glands. See MUMPS (INFECTIOUS PAROTITIS).

Back  -    New Search

parous (pa-rs) adj.

having given birth to one or more children.

Back  -    New Search

paroxetine (p-roks--teen) n.

an antidepressant drug that acts by prolonging the action of the neurotransmitter serotonin (5-hydroxytryptamine) in the brain (see SSRI). It is taken by mouth. Trade name: Seroxat .

Back  -    New Search

paroxysm (pa-rk-sizm) n.

1 a sudden violent attack, especially a spasm or convulsion.

2 the abrupt worsening of symptoms or recurrence of disease.
Top

—paroxysmal (pa-rk-siz-ml) adj.

Back  -    New Search

paroxysmal dyspnoea n.

attacks of breathlessness occurring at night due to left ventricular heart failure.

Back  -    New Search

paroxysmal tachycardia n.

abnormally increased heart rate due to impulses generated anywhere in the heart outside the natural pacemaker (sinoatrial node).

Back  -    New Search

parrot disease (pa-rt) n.

see PSITTACOSIS.

Back  -    New Search

pars (parz) n.

a specific part of an organ or other structure, such as any of parts of the pituitary gland.

Back  -    New Search

parthenogenesis (par-thin-oh-jen-i-sis) n.

reproduction in which an organism develops from an unfertilized ovum. It is common in plants and occurs in some lower animals (e.g. aphids).

Back  -    New Search

partially sighted register (par-sh-li) n.

(in Britain) a list of persons who have poor sight but are not technically blind. In general their sight is adequate to permit the performance of tasks for which some vision is essential. Compare BLIND REGISTER.

Back  -    New Search

partogram (par-toh-gram) n.

a graphic record of the course of labour.

Back  -    New Search

parturition (par-tewr-ish-n) n.

childbirth. See LABOUR.
—parturient (par-tewr-i-nt) adj.

Back  -    New Search

parvi- prefix

denoting small size.

Back  -    New Search

PAS n.

see PARA-AMINOSALICYLIC ACID.

Back  -    New Search

pascal (pas-kl) n.

the SI unit of pressure, equal to 1 newton per square metre. Symbol: Pa.

Back  -    New Search

Paschen bodies (pah-skn) pl. n.

particles that occur in the cells of skin rashes in patients with cowpox or smallpox; they are thought to be the virus particles. [E. Paschen (1860–1936), German pathologist]

Back  -    New Search

passive movement (pas-iv) n.

movement not brought about by a patient's own efforts. Passive movements are induced by manipulation of the joints by a physiotherapist. Compare ACTIVE MOVEMENT.

Back  -    New Search

Pasteurella (pas-cher-el-)

a genus of small rodlike Gram-negative bacteria that are parasites of animals and man. P. multocida a species that usually infects animals but may be transmitted to man through bites or scratches.

Back  -    New Search

pasteurization (pas-cher-l-zay-shn) n.

the treatment of milk by heating it to 65°C for 30 minutes, or to 72°C for 15 minutes, followed by rapid cooling, to kill such bacteria as those of tuberculosis and typhoid.

Back  -    New Search

pastille (pas-t'l) n.

a medicinal preparation containing gelatine and glycerine that is dissolved in the mouth so that the medication is applied to the mouth or throat.

Back  -    New Search

Patau syndrome (pat-ow) n.

a chromosome disorder in which there are three no. 13 chromosomes (instead of the usual two), causing mental retardation and defects in the heart, kidney, and scalp. Affected individuals rarely survive. [K. Patau (20th century), US geneticist]

Back  -    New Search

patch test (pach) n.

a test to discover which allergen is responsible for contact dermatitis in a patient. Very low concentrations of different allergens are applied under a patch on the back: a positive test will show an eczematous reaction.

Back  -    New Search

patella (p-tel-) n.

the lens-shaped bone that forms the kneecap. It is situated in front of the knee in the tendon of the quadriceps muscle of the thigh. See also SESAMOID BONE.
—patellar (p-tel-er) adj.

Back  -    New Search

patellar reflex n.

the knee jerk, in which stretching the muscle at the front of the thigh by tapping its tendon below the kneecap causes a reflex contraction of the muscle, so that the leg kicks.

Back  -    New Search

patellectomy (pat--lek-tmi) n.

surgical excision of the patella.

Back  -    New Search

patent (pay-tnt) adj.

open; unblocked. p. ductus arteriosus see DUCTUS ARTERIOSUS.

Back  -    New Search

path- (patho-) prefix

denoting disease.

Back  -    New Search

pathogen (pa-th-jen) n.

a microorganism, such as a bacterium, that parasitizes an animal (or plant) or man and produces a disease.

Back  -    New Search

pathogenesis (pa-th-jen-i-sis) n.

the origin and development of a disease.
—pathogenetic (pa-thoh-ji-net-ik) adj.

Back  -    New Search

pathogenic (pa-th-jen-ik) adj.

capable of causing disease. The term is applied to a parasitic microorganism (especially a bacterium) in relation to its host.
—pathogenicity n.

Back  -    New Search

pathognomonic (pa-thg-noh-mon-ik) adj.

describing a symptom or sign that is characteristic of or unique to a particular disease.

Back  -    New Search

pathological (pa-th-loj-ikl) adj.

relating to or arising from disease. p. fracture see FRACTURE.

Back  -    New Search

pathology (p-thol-ji) n.

the study of disease processes with the aim of understanding their nature and causes. clinical p. the application of the knowledge of disease processes to the treatment of patients.
—pathologist n.

Back  -    New Search

-pathy suffix

denoting 1 disease.

2 therapy.
Top

Back  -    New Search

patient allocation (pay-shnt al--kay-shn) n.

a method of organizing nursing care in which a nurse is allocated to care holistically for all the needs of a patient on a daily basis. Compare TASK ALLOCATION.

Back  -    New Search

Paul-Bunnell test (pawl-b-nel) n.

a haemagglutination test used in the diagnosis of glandular fever. [J. R. Paul (1893–1971) and W. W. Bunnell (1902–66), US physicians]

Back  -    New Search

Paul's tube (pawlz) n.

a glass tube with a projecting rim, used to drain the bowel after it has been brought to the surface of the abdomen and opened. [F. T. Paul (1851–1941), British surgeon]

Back  -    New Search

PCP n.

Pneumocystis carinii pneumonia. See PNEUMOCYSTIS.

Back  -    New Search

peak expiratory flow rate (PEFR) (peek eks-pir--ter-i floh rayt) n.

the rate at which a person can expel air from the lungs: a reliable measure of lung reserves in tests of vital capacity.

Back  -    New Search

Pearson bed (peer-sn) n.

a special type of hospital bed for nursing patients with fractures.

Back  -    New Search

peau d'orange (poh daw-rahnj) n.

a dimpled appearance of the skin over a breast tumour, resembling the surface of an orange. The skin is thickened and the openings of hair follicles and sweat glands are enlarged.

Back  -    New Search

pecten (pek-tin) n.

1 the middle section of the anal canal.

2 a sharp ridge on the upper branch of the pubis (part of the hip bone).
Top

—pectineal (pek-tin-il) adj.

Back  -    New Search

pectoral (pek-ter-l) adj.

relating to the chest or breast. p. girdle see SHOULDER GIRDLE. p. muscles the chest muscles: the pectoralis major, which draws the arm forward across the chest, and the pectoralis minor, which depresses the shoulder.

Back  -    New Search

pectoriloquy (pek-ter-il--kwi) n.

abnormal transmission of the patient's voice sounds through the chest wall so that they can be clearly heard through a stethoscope.

Back  -    New Search

pectus (pek-ts) n.

the chest or breast. p. carinatum see PIGEON CHEST. p. excavatum see FUNNEL CHEST.

Back  -    New Search

pedicle (ped-ikl) n.

1 the narrow neck of tissue connecting some tumours to the normal tissue from which they have developed.

2 (in plastic surgery) a narrow folded tube of skin by means of which a piece of skin used for grafting remains attached to its original site.
Top

3 (in anatomy) any slender stemlike process.
Top

Back  -    New Search

pediculicide (pi-dik-yoo-li-syd) n.

an agent that kills lice; examples include benzyl benzoate, carbaryl, and permethrin.

Back  -    New Search

pediculosis (pi-dik-yoo-loh-sis) n.

an infestation with lice which causes intense itching. Infestation with head lice (Pediculus humanis var. capitis) is quite common in schoolchildren and does not indicate poor hygiene; it may be treated with malathion, carbaryl, or permethrin lotions. By contrast, body lice (P. humanis corporis) affect vagrants, tramps, etc., and require treatment with lindane. Pubic lice (Phthirus pubis, the crab louse) are commonly sexually transmitted and respond to the same treatment as head lice.

Back  -    New Search

Pediculus (pi-dik-yoo-ls) n.

a widely distributed genus of lice. P. humanus capitis the head louse. P. humanus corporis the body louse, which in some parts of the world transmits relapsing fever and typhus. See also PEDICULOSIS.

Back  -    New Search

peduncle (pi-dunk-l) n.

a narrow process or stalklike structure, serving as a connection or support.

Back  -    New Search

PEFR n.

see PEAK EXPIRATORY FLOW RATE.

Back  -    New Search

Pel-Ebstein fever (pel-eb-styn) n.

a recurrent fever characteristic of patients with lymphoma or Hodgkin's disease. [P. K. Pel (1852–1919), Dutch physician; W. Ebstein (1836–1912), German physician]

Back  -    New Search

pellagra (pil-ag-r) n.

a nutritional disease due to a deficiency of nicotinic acid (a B vitamin). It is common in maize-eating communities. The symptoms of pellagra are scaly dermatitis on exposed surfaces, diarrhoea, and depression.

Back  -    New Search

pellet (pel-it) n.

a small pill, especially one used as an implant.

Back  -    New Search

pellicle (pel-ikl) n.

a thin layer of skin, membrane, or any other substance.

Back  -    New Search

pelvic girdle (hip girdle) (pel-vik) n

the bony structure to which the bones of the lower limbs are attached. It consists of the right and left hip bones.

Back  -    New Search

pelvic inflammatory disease (PID) n.

an acute or chronic condition in which the uterus, Fallopian tubes, and ovaries are inflamed and infected. The infection spreads from an adjacent infected organ (such as the appendix), ascends from the vagina (as in the case of chlamydial infection), or may be blood-borne (such as tuberculosis). The main feature is lower abdominal pain that may be severe; blocking of the Fallopian tubes is a common result; this can lead to ectopic pregnancy or infertility. In the chronic state, when pelvic adhesions have developed, surgical removal of the diseased tissue may be necessary.

Back  -    New Search

pelvimetry (pel-vim-itri) n.

the measurement of the four internal diameters of the pelvis, using an instrument called a pelvimeter . Pelvimetry helps in determining whether it will be possible for a fetus to be delivered in the normal way.

Back  -    New Search

pelvis (pel-vis) n. (pl. pelves)

1 the bony structure formed by the hip bones, sacrum, and coccyx (see illustration). The hip bones are fused at the back to the sacrum to form a rigid structure that protects the organs of the lower abdomen and provides attachment for the bones and muscles of the lower limbs.

2 the cavity within the bony pelvis.
Top

3 any structure shaped like a basin. renal p. the expanded part of the ureter in the kidney.

Top

—pelvic adj.

Back  -    New Search

pemoline (pem--leen) n.

a weak stimulant of the nervous system used to treat attention deficit disorder in children. It is administered by mouth. Trade name: Volital .

Back  -    New Search

pemphigoid (bullous pemphigoid) (pem-fig-oid) n.

a chronic itchy blistering disorder of the elderly. The blisters most commonly occur on the limbs and persist for several days, unlike those of pemphigus. Pemphigoid is an autoimmune disease and responds to treatment with corticosteroids or immunosuppressive drugs.

Back  -    New Search

pemphigus (pemphigus vulgaris) (pem-fig-s) n.

a rare but serious autoimmune skin disease marked by successive outbreaks of blisters. The blisters are superficial and do not remain intact for long; the mouth and other mucous membranes, as well as the skin, are usually affected. A number of milder variants of the disease exist.

Back  -    New Search

Pendred's syndrome (pen-drinds) n.

goitre associated with congenital deafness due to deficiency of peroxidase, an enzyme that is essential for the utilization of iodine. [V. Pendred (1869–1946), British physician]

Back  -    New Search

-penia suffix

denoting lack or deficiency.

Back  -    New Search

penicillamine (pen-i-sil--meen) n.

a drug that binds metals and therefore aids their excretion (see CHELATING AGENT). It is administered by mouth to treat Wilson's disease, metal poisoning, and severe rheumatoid arthritis. Trade names: Distamine , Pendramine .

Back  -    New Search

penicillin (pen-i-sil-in) n.

any one of a number of antibiotics derived from Penicillium moulds and used to treat infections caused by a wide variety of bacteria (see also BENETHAMINE PENICILLIN, BENZATHINE PENICILLIN). Some patients are allergic to penicillin and develop such reactions as skin rashes, swelling of the throat, and fever. p. G (or benzylpenicillin ) a form of penicillin usually administered by injection but taken orally to treat dental abscesses. p. V (or phenoxymethylpenicillin ) an orally administered form of penicillin. semisynthetic p. one of a number of antibiotics derived from the penicillins, such as amoxycillin, ampicillin, and cloxacillin.

Back  -    New Search

penicillinase (pen-i-sil-in-ayz) n.

an enzyme, produced by some bacteria, that is capable of antagonizing the antibacterial action of penicillin. Purified penicillinase may be used to treat reactions to penicillin.

Back  -    New Search

Penicillium (pen-i-sil-im) n.

a genus of mouldlike fungi that commonly grow on decaying fruit, bread, or cheese. Some species are pathogenic to man, causing diseases of the skin and respiratory tract. P. rubrum the major natural source of the antibiotic penicillin.

Back  -    New Search

penile prosthesis (pee-nyl) n.

see PROSTHESIS.

Back  -    New Search

penis (pee-nis) n.

the male organ that carries the urethra, through which urine and semen are discharged (see illustration). Most of the organ is composed of erectile tissue (corpus cavernosum and corpus spongiosum), which becomes filled with blood under conditions of sexual excitement so that the penis is erected. See also GLANS, PREPUCE.

—penile adj.

Back  -    New Search

pent- (penta-) prefix

denoting five.

Back  -    New Search

pentaerythritol (pen-t-i-rith-ri-tol) n.

a drug that dilates blood vessels and is administered by mouth in the treatment of angina and other heart conditions. Trade name: Mycardol .

Back  -    New Search

pentagastrin (pen-t-gas-trin) n.

a synthetic hormone that has the same effects as gastrin. It is injected to test for gastric secretion in the diagnosis of digestive disorders. Trade name: Peptavlon .

Back  -    New Search

pentamidine (pen-tam-i-deen) n.

a drug effective against protozoans and used in the treatment of Pneumocystis carinii pneumonia in AIDS patients, trypanosomiasis, and kala-azar. It is administered by injection or from an inhaler. Trade names: Pentam 300 , Nebupent .

Back  -    New Search

pentazocine (pen-taz-oh-seen) n.

a potent analgesic drug administered by mouth, injection, or in suppositories to relieve moderate or severe pain. Trade name: Fortral .

Back  -    New Search

pentose (pen-tohz) n.

a simple sugar with five carbon atoms: for example, ribose and xylose.

Back  -    New Search

pentosuria (pen-tohs-yoor-i) n.

an inborn defect of sugar metabolism causing abnormal excretion of pentose in the urine.

Back  -    New Search

Pentothal (pen-t-thal) n.

see THIOPENTONE.

Back  -    New Search

Peplau's model (pep-lowz) n.

a model for nursing based on interpersonal relations. It emphasizes that the therapeutic nurse-patient relationship is an integral part of nursing practice and that the nurse's role evolves as a result of it. See also NURSING MODELS. [H. Peplau (1909– ), US nurse theorist]

Back  -    New Search

peppermint (pep-er-mint) n.

an oil extracted from a species of mint (Mentha piperita), used as a carminative and flavouring agent.

Back  -    New Search

pepsin (pep-sin) n.

an enzyme in the stomach that begins the digestion of proteins by splitting them into peptones (see PEPTIDASE). It is produced by the action of hydrochloric acid on pepsinogen , which is secreted by the gastric glands.

Back  -    New Search

pepsinogen (pep-sin--jn) n.

see PEPSIN.

Back  -    New Search

peptic (pep-tik) adj.

1 relating to pepsin.

2 relating to digestion. p. ulcer a breach in the lining (mucosa) of the digestive tract produced by digestion of the mucosa by pepsin and acid. This may occur when pepsin and acid are present in abnormally high concentrations. See DUODENAL ULCER, GASTRIC (ULCER), OESOPHAGEAL ULCER.
Top

Back  -    New Search

peptidase (pep-tid-ayz) n.

one of a group of digestive enzymes that split proteins in the stomach and intestine into their constituent amino acids.

Back  -    New Search

peptide (pep-tyd) n.

a molecule consisting of two or more amino acids linked by bonds between the amino group and the carboxyl group. See also POLYPEPTIDE.

Back  -    New Search

peptone (pep-tohn) n.

a large protein fragment produced by the action of enzymes on proteins in the first stages of protein digestion.

Back  -    New Search

peptonuria (pep-tohn-yoor-i) n.

the presence in the urine of peptones.

Back  -    New Search

perception (per-sep-shn) n.

(in psychology) the process by which information about the world, received by the senses, is analysed and made meaningful.

Back  -    New Search

percussion (per-kush-n) n.

the technique of examining part of the body by tapping it with the fingers or an instrument (plessor) and sensing the resultant vibrations. It is used to detect the presence of fluid or abnormal solidification or enlargement in different organs.

Back  -    New Search

percutaneous (per-kew-tay-nis) adj.

through the skin: often applied to the route of administration of drugs in ointments, etc., which are absorbed through the skin. p. epididymal sperm aspiration see PESA. p. nephrolithotomy see NEPHROLITHOTOMY. p. transhepatic cholangiopancreatography see CHOLANGIOPANCREATOGRAPHY.

Back  -    New Search

perforation (per-fer-ay-shn) n.

the creation of a hole in an organ, tissue, or tube. This may occur in the course of a disease, such as duodenal ulcer, colonic diverticulitis, or stomach cancer. Treatment is usually by surgical repair of the perforation, but conservative treatment with antibiotics may result in spontaneous healing. Perforation may also be caused accidentally by instruments (for example a curette may perforate the uterus) or by injury (for example to the eardrum).

Back  -    New Search

performance indicators (PIs) (per-for-mnss) pl. n.

statistical information, based on quantitative measures of the resources and activities of the NHS, produced by health authorities and sent to the Department of Health. This enables comparisons of performance of one section with that achieved by another to be analysed and published.

Back  -    New Search

perfusion (per-few-zhn) n.

1 the passage of fluid through a tissue, especially the passage of blood through the lung tissue to pick up oxygen in the alveoli and release carbon dioxide.

2 the deliberate introduction of fluid into a tissue, usually by injection into the blood vessels supplying the tissue.
Top

Back  -    New Search

perfusion scan n.

the demonstration of abnormal structures or blood supply of an organ by the perfusion of radioactive or radiopaque substances.

Back  -    New Search

pergolide (per-g-lyd) n.

a drug that is used in the treatment of parkinsonism. It is administered by mouth. Trade name: Celance .

Back  -    New Search

peri- prefix

denoting near, around, or enclosing.

Back  -    New Search

periadenitis (pe-ri-ad-in-I-tis) n.

inflammation of tissues surrounding a gland.

Back  -    New Search

perianal haematoma (external haemorrhoid) (pe-ri-ay-nl) n.

a small painful swelling beside the anus, occurring after a bout of straining to pass faeces or coughing. Perianal haematomas are caused by the rupture of a small vein in the anus.

Back  -    New Search

periarteritis nodosa (pe-ri-ar-ter-l-tis) n.

see POLYARTERITIS NODOSA.

Back  -    New Search

periarthritis (pe-ri-arth-ry-tis) n.

inflammation of tissues around a joint capsule, including tendons and bursae. chronic p. a common cause of pain and stiffness of the shoulder; it usually responds to local steroid injections or physiotherapy.

Back  -    New Search

pericard- (pericardio-) prefix

denoting the pericardium.

Back  -    New Search

pericardiectomy (pericardectomy) (pe-ri-kar-di-ek-tmi) n.

surgical removal of the pericardium. It is used in the treatment of chronic constrictive pericarditis and chronic pericardial effusion (see PERICARDITIS).

Back  -    New Search

pericardiocentesis (pe-ri-kar-di-oh-sen-tee-sis) n.

removal of excess fluid from within the pericardium by means of needle aspiration.

Back  -    New Search

pericardiorrhaphy (pe-ri-kar-di-o-rfi) n.

the repair of wounds in the pericardium, such as those due to injury or surgery.

Back  -    New Search

pericardiostomy (pe-ri-kar-di-ost-mi) n.

an operation in which the pericardium is opened and the fluid within drained via a tube. It is sometimes used in the treatment of septic pericarditis.

Back  -    New Search

pericardiotomy (pericardotomy) (pe-ri-kar-di-ot-mi) n.

surgical opening or puncture of the pericardium. It is required to gain access to the heart in heart surgery and to remove excess fluid from within the pericardium.

Back  -    New Search

pericarditis (pe-ri-kar-dy-tis) n.

acute or chronic inflammation of the pericardium. Pericarditis may be seen alone or as part of pancarditis. It has numerous causes, including virus infections, uraemia, and cancer. acute p. pericarditis characterized by fever, chest pain, and a pericardial friction rub. Fluid may accumulate within the pericardial sac (pericardial effusion ). chronic constrictive p. chronic thickening of the pericardium, which interferes with activity of the heart and has many features in common with heart failure.

Back  -    New Search

pericardium (pe-ri-kar-dim) n.

the membrane surrounding the heart. fibrous p. the outer portion of the pericardium, which completely encloses the heart and is attached to the large blood vessels emerging from the heart. serous p. the internal portion of the pericardium: a closed sac of serous membrane containing a very small amount of fluid, which prevents friction between the two surfaces as the heart beats.
—pericardial adj.

Back  -    New Search

pericardotomy (pe-ri-kar-dot-mi) n.

see PERICARDIOTOMY.

Back  -    New Search

perichondritis (pe-ri-kon-dry-tis) n.

inflammation of cartilage and surrounding soft tissues, usually due to chronic infection. A common site is the external ear.

Back  -    New Search

perichondrium (pe-ri-kon-drim) n.

the dense layer of fibrous connective tissue that covers the surface of cartilage.

Back  -    New Search

pericranium (pe-ri-kray-nim) n.

the periosteum of the skull.

Back  -    New Search

pericystitis (pe-ri-sis-ty-tis) n.

inflammation in the tissues around the bladder, causing pain in the pelvis, fever, and symptoms of cystitis. It usually results from infection in the Fallopian tubes or uterus.

Back  -    New Search

perifolliculitis (pe-ri-f-lik-yoo-ly-tis) n.

inflammation around the hair follicles.

Back  -    New Search

perihepatitis (pe-ri-hep--ty-tis) n.

inflammation of the membrane covering the liver. It is usually associated with abnormalities of the liver or chronic peritonitis.

Back  -    New Search

perilymph (pe-ri-limf) n.

the fluid between the bony and membranous labyrinths of the ear.

Back  -    New Search

perimenopause (pe-ri-men--pawz) n.

the period of time around the menopause in which marked changes in the menstrual cycle occur, usually accompanied by hot flushes, and in which no 12 consecutive months of amenorrhoea have yet occurred.

Back  -    New Search

perimeter (per-im-it-er) n.

an instrument for mapping the absolute extent of the visual field and detecting any gaps or defects.
—perimetry n.

Back  -    New Search

perimetritis (pe-ri-mi-try-tis) n.

inflammation of the membrane on the outer surface of the uterus. The condition may be associated with parametritis.

Back  -    New Search

perimetrium (pe-ri-mee-trim) n.

the peritoneum of the uterus.

Back  -    New Search

perimysium (pe-ri-mis-im) n.

the fibrous sheath that surrounds each bundle of muscle fibres.

Back  -    New Search

perinatal (pe-ri-nay-t'l) adj.

relating to the period starting a few weeks before birth and including the birth and a few weeks after birth. p. mortality rate the number of stillbirths and first-week or neonatal deaths per 1000 live births.

Back  -    New Search

perineal (pe-ri-nee-l) adj.

relating to the perineum. p. descent abnormal bulging down of the perineum due to weakness of the pelvis floor muscles. p. pouch see ILEAL POUCH.

Back  -    New Search

perineoplasty (pe-ri-nee-oh-plasti) n.

an operation designed to enlarge the vaginal opening by incising the hymen and part of the perineum (Fenton's operation ).

Back  -    New Search

perineorrhaphy (pe-ri-ni-o-rfi) n.

the surgical repair of a damaged perineum. The damage is usually the result of a tear in the perineum sustained during childbirth.

Back  -    New Search

perinephric (pe-ri-nef-rik) adj.

around the kidney. p. abscess a collection of pus around the kidney, usually secondary to pyonephrosis.

Back  -    New Search

perinephritis (pe-ri-ni-fry-tis) n.

inflammation of the tissues around the kidney, usually due to spread of infection from the kidney itself. The patient has pain in the loins, fever, and fits of shivering.

Back  -    New Search

perineum (pe-ri-nee-m) n.

the region of the body between the anus and the urethral opening, including both skin and underlying muscle.

Back  -    New Search

perineurium (pe-ri-newr-im) n.

the sheath of connective tissue that surrounds individual bundles of nerve fibres within a large nerve.

Back  -    New Search

periocular (pe-ri-ok-yoo-ler) adj.

adjacent to the eyeball.

Back  -    New Search

periodic fever (peer-i-od-ik) n.

see MALARIA.

Back  -    New Search

periodontal (pe-ri--don-t'l) adj.

denoting or relating to the tissues surrounding the teeth. p. disease disease of the tissues that support and attach the teeth – the gums, periodontal membrane, and alveolar bone: the most common cause of tooth loss in older people. p. membrane (p. ligament ) the ligament around a tooth, by which it is attached to the bone.

Back  -    New Search

periodontium (pe-ri--don-tim) n.

the tissues, collectively, surrounding the teeth: the gums (gingiva), periodontal membrane, and alveolar bone.

Back  -    New Search

periodontology (pe-ri--don-tol-ji) n.

the branch of dentistry concerned with the tissues that support and attach the teeth and the prevention and treatment of periodontal disease.

Back  -    New Search

periorbital (pe-ri-or-bit-l) adj.

1 around the eye socket (orbit).

2 relating to the periosteum within the orbit.
Top

Back  -    New Search

periosteotome (pe-ri-ost-i--tohm) n.

an instrument used for cutting the periosteum and separating it from the underlying bone.

Back  -    New Search

periosteum (pe-ri-ost-im) n.

a layer of dense connective tissue that covers the surface of a bone and provides attachment for muscles, tendons, and ligaments. The outer layer of the periosteum contains a large number of blood vessels; the inner layer contains osteoblasts and fewer blood vessels.
—periosteal adj.

Back  -    New Search

periostitis (pe-ri-ost-l-tis) n.

inflammation of the periosteum. acute p. periostitis that results from direct injury to the bone and is associated with a haematoma, which may later become infected. chronic p. periostitis that is often due to an inflammatory disease, such as tuberculosis or syphilis, or to a chronic ulcer overlying the bone involved.

Back  -    New Search

peripheral nervous system (per-if-er-l) n.

all parts of the nervous system lying outside the central nervous system. It includes the cranial nerves and spinal nerves and their branches and the autonomic nervous system.

Back  -    New Search

periphlebitis (pe-ri-fli-by-tis) n.

inflammation of the tissues around a vein: seen as an extension of phlebitis.

Back  -    New Search

periproctitis (pe-ri-prok-ty-tis) n.

inflammation of the tissues around the rectum and anus.

Back  -    New Search

perisalpingitis (pe-ri-sal-pin-jy-tis) n.

inflammation of the peritoneal membrane on the outer surface of a Fallopian tube.

Back  -    New Search

perisplenitis (pe-ri-spli-ny-tis) n.

inflammation of the external coverings of the spleen.

Back  -    New Search

peristalsis (pe-ri-stal-sis) n.

a wavelike movement that progresses along some of the hollow muscular tubes of the body, such as the intestines. It occurs involuntarily, induced by distension of the walls of the tube. Alternate contraction and relaxation of the circular and longitudinal muscles tends to push the contents of the tube forward.
—peristaltic adj.

Back  -    New Search

peritendinitis (pe-ri-ten-di-ny-tis) n.

see TENOSYNOVITIS.

Back  -    New Search

peritomy (per-it-mi) n.

an eye operation in which an incision of the conjunctiva is made in a complete circle around the cornea.

Back  -    New Search

peritoneoscope (pe-ri-tn-ee--skohp) n.

see LAPAROSCOPE.

Back  -    New Search

peritoneum (pe-ri-tn-ee-m) n.

the serous membrane of the abdominal cavity (see illustration). parietal p. the part of the peritoneum that lines the walls of the abdomen. visceral p. the part of the peritoneum that covers the abdominal organs. See also MESENTERY, OMENTUM.

—peritoneal adj.

Back  -    New Search

peritonitis (pe-ri-tn-l-tis) n.

inflammation of the peritoneum. primary p. peritonitis caused by bacteria spread via the bloodstream. Symptoms are diffuse abdominal pain and swelling, with fever and weight loss. secondary p. peritonitis due to perforation or rupture of an abdominal organ, such as the vermiform appendix, allowing access of bacteria and irritant digestive juices to the peritoneum. This produces sudden severe abdominal pain and shock. Treatment is usually by surgical repair of the perforation.

Back  -    New Search

peritonsillar abscess (pe-ri-ton-sil-er) n.

see QUINSY.

Back  -    New Search

peritrichous (pe-ri-try-ks) adj.

describing bacteria in which the flagella cover the entire cell surface.

Back  -    New Search

perityphlitis (pe-ri-tif-ly-tis) n.

Archaic. inflammation of the tissues around the caecum. See TYPHLITIS.

Back  -    New Search

periureteritis (pe-ri-yoor-i-ter-I-tis) n.

inflammation of the tissues around a ureter. This is usually associated with inflammation of the ureter itself (see URETERITIS) often behind an obstruction caused by a stone or stricture.

Back  -    New Search

PERLA

pupils equal, react to light and accommodation: used in hospital notes.

Back  -    New Search

perle (perl) n.

a soft capsule containing medicine.

Back  -    New Search

perleche (per-lesh) n.

dryness and cracking of the corners of the mouth, sometimes with infection. Perleche may be caused by persistent lip licking or by a vitamin-deficient diet.

Back  -    New Search

permeability (per-mi--bil-iti) n.

the ability of membranes to allow soluble substances to pass through them. See also SEMIPERMEABLE MEMBRANE.
—permeable (per-mi-bl) adj.

Back  -    New Search

permethrin (per-meeth-rin) n.

a synthetic derivative of the naturally occurring insecticide pyrethrin that is applied externally to treat head lice and scabies. Trade name: Lyclear .

Back  -    New Search

pernicious (per-nish-s) adj.

describing diseases that are highly dangerous or likely to result in death if untreated. p. anaemia a form of anaemia resulting from deficiency of vitamin B_12, due either to failure to produce intrinsic factor or to dietary deficiency of the vitamin. It is characterized by defective production of red blood cells and the presence of megaloblasts in the bone marrow.

Back  -    New Search

pernio (per-ni-oh) n.

the medical name for a chilblain (see CHILBLAINS).

Back  -    New Search

perniosis (per-ni-oh-sis) n.

see CHILBLAINS.

Back  -    New Search

pero- prefix

denoting deformity; defect.

Back  -    New Search

peromelia (pe-roh-mee-li) n.

congenital deformity of one or more limbs.

Back  -    New Search

peroneal (pe-r-nee-l) adj.

relating to or supplying the outer (fibular) side of the leg.

Back  -    New Search

peroneus (pe-r-nee-s) n.

one of the muscles of the leg that arises from the fibula and helps to turn the foot outwards.

Back  -    New Search

peroral (per-or-l) adj.

through the mouth.

Back  -    New Search

perphenazine (per-fen--zeen) n.

a phenothiazine antipsychotic drug administered by mouth or injection to relieve anxiety, tension, and agitation and to prevent nausea and vomiting. Trade name: Fentazin .

Back  -    New Search

perseveration (per-sev-er-ay-shn) n.

1 excessive persistence at a task that prevents the individual from turning his attention to new situations. It is a symptom of organic disease of the brain and sometimes of obsessional neurosis.

2 the phenomenon in which an image continues to be perceived briefly in the absence of the object. This is a potentially serious neurological disorder.
Top

Back  -    New Search

persistent vegetative state (PVS) (per-sist-nt) n.

the condition of living like a vegetable, without consciousness or the ability to initiate voluntary action, as a result of brain damage. People in the vegetative state may sometimes give the appearance of being awake and conscious, with open eyes. They may make random movements of the limbs or head and may pick or rub with the fingers, but there is no response to any form of communication and no reason to suppose that there is any awareness of the environment. Compare LOCKED-IN SYNDROME.

Back  -    New Search

personality (per-sn-al-iti) n.

(in psychology) an enduring disposition to act and feel in particular ways that differentiate one individual from another.

Back  -    New Search

personality disorder n.

a deeply ingrained and maladaptive pattern of behaviour, which persists through many years and causes suffering, either to the patient or to other people (or to both). See HYSTERICAL, PARANOID, SCHIZOID PERSONALITY.

Back  -    New Search

perspiration (per-sper-ay-shn) n.

sweat or the process of sweating. insensible p. sweat that evaporates immediately from the skin and is therefore not visible. sensible p. sweat that is visible on the skin in the form of drops.

Back  -    New Search

Perthes' disease (per-tiz) n.

see LEGG-CALVÉ-PERTHES DISEASE.

Back  -    New Search

pertussis (per-tus-iss) n.

see WHOOPING COUGH.

Back  -    New Search

pes (payz) n.

(in anatomy) the foot or a part resembling a foot. p. clavus see CLAW-FOOT. p. planus see FLAT-FOOT.

Back  -    New Search

PESA (percutaneous epididymal sperm aspiration) n.

a method of removing spermatozoa directly from the epididymis, a new technique used in assisted conception. The sperm are then used to fertilize egg cells in vitro.

Back  -    New Search

pessary (pess-er-i) n.

1 a plastic device, often ring-shaped, that fits into the vagina and keeps the uterus in position: used to treat prolapse.

2 a plug or cylinder of soft material containing a drug that is fitted into the vagina for the treatment of such disorders as vaginitis. Also called: vaginal suppository .
Top

Back  -    New Search

pesticide (pest-i-syd) n.

a chemical agent, such as parathion, used to kill insects or other organisms harmful to crops and other cultivated plants.

Back  -    New Search

PET n.

see POSITRON EMISSION TOMOGRAPHY.

Back  -    New Search

petechiae (pi-tee-ki-ee) pl. n.

small round flat dark-red spots caused by bleeding into the skin or beneath the mucous membrane.

Back  -    New Search

pethidine (meperidine) (peth-i-deen) n.

a potent analgesic drug with mild sedative action, administered by mouth or injection to relieve moderate or severe pain.

Back  -    New Search

petit mal (pe-tee mal) n.

see EPILEPSY.

Back  -    New Search

Petri dish (pet-ri) n.

a flat shallow circular glass or plastic dish with a pillbox-like lid, used to hold solid agar or gelatin media for culturing bacteria. [J. R. Petri (1852–1921), German bacteriologist]

Back  -    New Search

petrissage (pay-tri-sahzh) n.

kneading: a form of massage in which the skin is lifted up, pressed down and squeezed, and pinched and rolled.

Back  -    New Search

petrositis (pet-roh-sy-tis) n.

inflammation of the petrous part of the temporal bone, usually due to an extension of mastoiditis.

Back  -    New Search

petrous bone (pet-rs) n.

see TEMPORAL BONE.

Back  -    New Search

Peutz-Jeghers syndrome (puuts-yeg-erz) n.

a hereditary disorder in which the presence of multiple polyps in the lining of the small intestine (intestinal polyposis) is associated with pigmented areas (similar to freckles) around the lips, on the inside of the mouth, and on the palms and soles. [J. L. A. Peutz (1886–1957), Dutch physician; H. J. Jeghers (1904– ), US physician]

Back  -    New Search

-pexy suffix

denoting surgical fixation.

Back  -    New Search

Peyer's patches (py-erz) pl. n.

oval masses of lymphoid tissue on the mucous membrane lining the small intestine. [J. C. Peyer (1653–1712), Swiss anatomist]

Back  -    New Search

Peyronie's disease (pay-roh-neez) n.

a dense fibrous plaque in the penis. The penis curves or angulates at this point on erection and pain often results. [F. de la Peyronie (1678–1747), French surgeon]

Back  -    New Search

pH n.

a measure of the concentration of hydrogen ions in a solution, and therefore of its acidity or alkalinity. A pH of 7 indicates a neutral solution, a pH below 7 indicates acidity, and a pH in excess of 7 indicates alkalinity.

Back  -    New Search

phaco- (phako-) prefix

denoting the lens of the eye.

Back  -    New Search

phacoemulsification (phakoemulsification) (fak-i-mul-si-fi-kay-shn) n.

a widely used method of cataract extraction in which a high-frequency ultrasound probe is used to break up a cataract so that it can be removed through a very small incision.

Back  -    New Search

phaeochromocytoma (fi-oh-kroh-moh-sy-toh-m) n.

a small vascular tumour of the medulla of the adrenal gland. By its uncontrolled and irregular secretion of the hormones adrenaline and noradrenaline, the tumour causes attacks of raised blood pressure, increased heart rate, palpitations, and headache.

Back  -    New Search

phag- (phago-) prefix

denoting 1 eating.

2 phagocytes.
Top

Back  -    New Search

phage (fayj) n.

see BACTERIOPHAGE.

Back  -    New Search

-phagia suffix

denoting a condition involving eating.

Back  -    New Search

phagocyte (fag--syt) n.

a cell that is able to engulf and digest bacteria, protozoa, cells and cell debris, and other small particles. Phagocytes include many white blood cells and macrophages, which play a major role in the body's defence mechanism.
—phagocytic adj.

Back  -    New Search

phagocytosis (fag--sy-toh-sis) n.

the engulfment and digestion of bacteria and other foreign particles by a phagocyte. Compare PINOCYTOSIS.

Back  -    New Search

phako- prefix.

see PHACO-.

Back  -    New Search

phalanges (f-lan-jeez) n. (sing. phalanx)

the bones of the fingers and toes (digits). The first digit (thumb/big toe) has two phalanges. Each of the remaining digits has three phalanges.
—phalangeal adj.

Back  -    New Search

phalangitis (fal-n-jy-tis) n.

inflammation of a finger or toe, caused by infection of the soft tissues, bone, or joints or by rheumatic diseases. See also DACTYLITIS.

Back  -    New Search

phalanx (fal-anks) n.

see PHALANGES.

Back  -    New Search

phalloplasty (fal-oh-plasti) n.

surgical reconstruction or repair of the penis, performed to correct a congenital deformity or following injury to the penis.

Back  -    New Search

phallus (fal-s) n.

the embryonic penis, before the urethral duct has reached its final state of development.

Back  -    New Search

phantom limb (fan-tm) n.

the sensation that an arm or leg, or part of an arm or leg, is still attached to the body after it has been amputated.

Back  -    New Search

phantom pregnancy n.

see PSEUDOCYESIS.

Back  -    New Search

phantom tumour n.

a swelling, in the abdomen or elsewhere, caused by local muscular contraction or the accumulation of gases, that mimics a swelling caused by a tumour. The condition is usually associated with emotional disorder.

Back  -    New Search

pharmaceutical (farm--sewt-ikl) adj.

relating to pharmacy.

Back  -    New Search

pharmacist (farm--sist) n.

a person who is qualified by examination and registered and authorized to dispense medicines.

Back  -    New Search

pharmaco- prefix

denoting drugs.

Back  -    New Search

pharmacodynamics (farm--koh-dy-nam-iks) n.

the interaction of drugs with cells. It includes such factors as the binding of drugs to cells, their uptake, and intracellular metabolism.

Back  -    New Search

pharmacokinetics (farm--koh-ki-net-iks) n.

the handling of a drug within the body, which includes its absorption, distribution in the body, metabolism, and excretion.

Back  -    New Search

pharmacology (farm--kol-ji) n.

the science of the properties of drugs and their effects on the body.
—pharmacological adj. —pharmacologist n.

Back  -    New Search

pharmacopoeia (farm--k-pee-) n.

a book containing a list of the drugs used in medicine, with details of their formulae, methods of preparation, dosages, standards of purity, etc.

Back  -    New Search

pharmacy (farm-si) n.

1 the preparation and dispensing of drugs.

2 premises registered to dispense medicines and sell poisons.
Top

Back  -    New Search

pharyng- (pharyngo-) prefix

denoting the pharynx.

Back  -    New Search

pharyngeal pouch (branchial or visceral pouch) (fa-rin-jee-l) n.

any of the paired segmented pouches in the side of the throat of the early embryo. They give rise to the tympanic cavity, the parathyroid glands, the thymus, and probably the thyroid gland.

Back  -    New Search

pharyngectomy (fa-rin-jek-tmi) n.

surgical removal of part of the pharynx.

Back  -    New Search

pharyngitis (fa-rin-jy-tis) n.

inflammation of the pharynx. It produces sore throat and may be associated with tonsillitis.

Back  -    New Search

pharyngocele (f-ring-oh-seel) n.

a pouch or cyst opening off the pharynx (see BRANCHIAL CYST).

Back  -    New Search

pharyngolaryngeal (f-ring-oh-la-rin-jee-l) adj.

relating to both the pharynx and the larynx.

Back  -    New Search

pharyngoscope (f-ring--skohp) n.

an endoscope for the examination of the pharynx.

Back  -    New Search

pharyngotympanic tube (f-ring-oh-tim-pan-ik) n.

see EUSTACHIAN TUBE.

Back  -    New Search

pharynx (fa-rinks) n.

a muscular tube, lined with mucous membrane, that extends from the beginning of the oesophagus (gullet) up to the base of the skull. It communicates with the posterior nares, Eustachian tube, mouth, larynx, and oesophagus. The pharynx acts as a passageway for food, as an air passage from the nasal cavity and mouth to the larynx, and as a resonating chamber for the sounds produced in the larynx.
—pharyngeal adj.

Back  -    New Search

phenazocine (fin-az-oh-seen) n.

an analgesic drug administered by mouth or injection for rapid relief of moderate or severe pain. Trade name: Narphen .

Back  -    New Search

phenazopyridine (fen--zoh-pi-ri-deen) n.

an analgesic drug administered by mouth to relieve pain in inflammatory conditions of the bladder and urinary tract, such as cystitis and urethritis. Trade name: Pyridium .

Back  -    New Search

phenelzine (fen-l-zeen) n.

a drug administered by mouth to relieve depression and anxiety (see MAO INHIBITOR). Trade name: Nardil .

Back  -    New Search

phenindione (fen-in-di-ohn) n.

an anticoagulant drug administered by mouth or injection to treat thrombosis in the blood vessels of the heart and limbs. Trade name: Dindevan .

Back  -    New Search

pheniodol (fin-l--dol) n.

an iodine-containing compound that is used as a contrast medium during X-ray examination of the gall bladder (see CHOLECYSTOGRAPHY).

Back  -    New Search

pheniramine (fen-eer--meen) n.

an antihistamine used to treat allergic reactions such as hay fever and urticaria. It is administered by mouth or is applied to the skin in an ointment. Trade name: Daneral .

Back  -    New Search

phenobarbitone (fee-noh-bar-bit-ohn) n.

a barbiturate drug administered by mouth or injection to treat insomnia and anxiety and as an anticonvulsant in the treatment of epilepsy.

Back  -    New Search

phenol (carbolic acid) (fee-nol) n.

a strong disinfectant used for cleansing wounds, treating inflammations of the mouth, throat, and ear, and as a preservative in injections. It is administered as solution, ointments, and lotions and is highly toxic if taken by mouth.

Back  -    New Search

phenolphthalein (fee-nol-thal-i-in) n.

an irritant laxative administered by mouth, usually given at night to act the following morning.

Back  -    New Search

phenolsulphonphthalein (fee-nol-sul-fohn-thal-i-in) n.

a red dye administered by injection in a test for kidney function.

Back  -    New Search

phenothiazines (fee-noh-th'y--zeenz) pl. n.

a group of chemically related compounds with various pharmacological actions. Some (e.g. chlorpromazine) are antipsychotic drugs; others (e.g. piperazine) are anthelmintics.

Back  -    New Search

phenotype (fee-noh-typ) n.

the observable characteristics of an individual, which result from interaction between his genotype and the environment.

Back  -    New Search

phenoxybenzamine (fin-oks-i-ben-z-meen) n.

a drug that dilates blood vessels (see ALPHA BLOCKER). It is administered by mouth or injection to reduce blood pressure and to treat conditions involving poor circulation, such as Raynaud's disease and chilblains. Trade name: Dibenyline .

Back  -    New Search

phenoxymethylpenicillin (fin-oks-i-meth-il-pen-i-sil-in) n.

see PENICILLIN.

Back  -    New Search

phensuximide (fen-suks-i-myd) n.

an anticonvulsant drug administered by mouth to prevent or reduce absence seizures in epilepsy.

Back  -    New Search

phentermine (fen-ter-meen) n.

a sympathomimetic drug that suppresses the appetite and is administered by mouth in the treatment of obesity. Trade names: Duromine , lonamin .

Back  -    New Search

phentolamine (fen-tol--meen) n.

a drug that dilates blood vessels (see ALPHA BLOCKER) and is administered by mouth or injection to reduce blood pressure in phaeochromocytoma and to treat conditions of poor circulation, such as Raynaud's disease and chilblains. Trade name: Rogitine .

Back  -    New Search

phenylalanine (fee-nyl-al--neen) n.

an essential amino acid that is readily converted to tyrosine. Blockade of this metabolic pathway gives rise to phenylketonuria.

Back  -    New Search

phenylbutazone (fee-nyl-bew-t-zohn) n.

an analgesic drug that reduces fever and inflammation and is administered by mouth or injection to relieve pain in rheumatic and related diseases. Trade name: Butazolidin .

Back  -    New Search

phenylephrine (fee-nyl-ef-reen) n.

a drug that constricts blood vessels (see SYMPATHOMIMETIC). It is given by injection to increase blood pressure, in a nasal spray to relieve nasal congestion, and in eye drops to dilate the pupils. Trade name: Minims phenylephrine .

Back  -    New Search

phenylketonuria (fee-nyl-kee-tn-yoor-i) n.

an inherited defect of protein metabolism (see INBORN ERROR OF METABOLISM) causing an excess of the amino acid phenylalanine in the blood, which damages the nervous system and leads to severe mental retardation. The gene responsible for phenylketonuria is recessive, so that a child is affected only if both parents are carriers of the defective gene.

Back  -    New Search

phenytoin (fen-i-toh-in) n.

an anticonvulsant drug administered by mouth or injection to control major and focal epileptic seizures. Trade name: Epanutin .

Back  -    New Search

phial (fy-l) n.

a small glass bottle for storing medicines or poisons.

Back  -    New Search

-philia suffix

denoting morbid craving or attraction.

Back  -    New Search

phimosis (fy-moh-sis) n.

narrowing of the opening of the foreskin, which cannot therefore be drawn back over the underlying glans penis.

Back  -    New Search

phleb- (phlebo-) prefix

denoting a vein or veins.

Back  -    New Search

phlebectomy (fli-bek-tmi) n.

the surgical removal of a vein (or part of a vein), sometimes performed for the treatment of varicose veins in the legs (varicectomy ).

Back  -    New Search

phlebitis (fli-by-tis) n.

inflammation of the wall of a vein, which is most commonly seen in the legs as a complication of varicose veins. A segment of vein becomes painful and tender and the surrounding skin feels hot and appears red. Thrombosis commonly develops (see THROMBOPHLEBITIS). Treatment consists of elastic support and administration of drugs, such as phenylbutazone.

Back  -    New Search

phlebography (fli-bog-rfi) n.

see VENOGRAPHY.

Back  -    New Search

phlebolith (flee-boh-lith) n.

a stone-like structure that results from deposition of calcium in a venous blood clot.

Back  -    New Search

phlebothrombosis (flee-boh-throm-boh-sis) n.

obstruction of a vein by a blood clot, without preceding inflammation of its wall. It is most common within the deep veins of the calf of the leg (deep vein thrombosis , DVT). The affected leg may become swollen and tender and the clot may become detached and give rise to pulmonary embolism.
Prolonged bed rest, heart failure, pregnancy, injury, and surgery predispose to thrombosis by encouraging sluggish blood flow. Anticoagulant drugs (such as heparin and warfarin) are used in prevention and treatment.

Back  -    New Search

phlebotomy (venesection) (fli-bot-mi) n.

the surgical opening or puncture of a vein in order to remove blood (in the treatment of polycythaemia) or to infuse fluids, blood, or drugs in the treatment of many conditions.

Back  -    New Search

phlegm (flem) n.

a nonmedical term for sputum.

Back  -    New Search

phlegmasia (fleg-may-zi) n.

inflammation. p. alba dolens see WHITE LEG.

Back  -    New Search

phlycten (flik-tn) n.

a small pinkish-yellow nodule surrounded by a zone of dilated blood vessels that occurs in the conjunctiva or in the cornea. Phlyctens are thought to be due to a type of allergy to certain bacteria.

Back  -    New Search

phobia (foh-bi) n.

a pathologically strong fear of a particular event or thing. Avoiding the feared situation may severely restrict one's life and cause much suffering. Treatment is with behaviour therapy, especially desensitization and flooding. Psychotherapy and drug therapy are also useful.

Back  -    New Search

-phobia suffix

denoting morbid fear or dread.

Back  -    New Search

phocomelia (foh-koh-mee-li) n.

congenital absence of the upper arm and/or upper leg, the hands or feet or both being attached to the trunk by a short stump.

Back  -    New Search

pholcodine (fol-k-deen) n.

a drug that suppresses coughs and reduces irritation in the respiratory system (see ANTITUSSIVE). It is administered by mouth in cough mixtures. Trade names: Galenphol , Pholcomed .

Back  -    New Search

phon- (phono-) prefix

denoting sound or voice.

Back  -    New Search

phonation (foh-nay-shn) n.

the production of vocal sounds, particularly speech.

Back  -    New Search

phoniatrics (foh-ni-at-riks) n.

the study of the voice and its disorders.

Back  -    New Search

phonocardiogram (foh-noh-kar-di--gram) n.

see ELECTROCARDIOPHONOGRAPHY.
—phonocardiography (foh-noh-kar-di-og-rfi) n.

Back  -    New Search

phonosurgery (foh-noh-serj-er-i) n.

surgery performed on the larynx externally or endoscopically to improve or modify the quality of the voice.

Back  -    New Search

-phoria suffix

denoting (in ophthalmology) an abnormal deviation of the eyes or turning of the visual axis.

Back  -    New Search

phosgene (fos-jeen) n.

a poisonous gas developed during World War I. It is a choking agent, acting on the lungs to produce oedema, with consequent respiratory and cardiac failure.

Back  -    New Search

phosphagen (fos-f-jn) n.

creatine phosphate (see CREATINE).

Back  -    New Search

phosphataemia (fos-f-tee-mi) n.

the presence of phosphates in the blood. Sodium, calcium, potassium, and magnesium phosphates are normal constituents.

Back  -    New Search

phosphatase (fos-f-tayz) n.

one of a group of enzymes capable of catalysing the hydrolysis of phosphoric acid esters. Phosphatases are important in the absorption and metabolism of carbohydrates, nucleotides, and phospholipids and are essential in the calcification of bone. acid p. a phosphatase present in kidney, semen, serum, and the prostate gland. alkaline p. a phosphatase that occurs in teeth, developing bone, plasma, kidney, and intestine.

Back  -    New Search

phosphate (fos-fayt) n.

any salt or ester of phosphoric acid.

Back  -    New Search

phosphatidylcholine (fos-fat-i-dil-koh-leen) n.

see LECITHIN.

Back  -    New Search

phosphaturia (phosphuria) (fos-ft-yoor-i) n.

the presence of an abnormally high concentration of phosphates in the urine, making it cloudy. The condition may be associated with the formation of calculi in the kidneys or bladder.

Back  -    New Search

phosphocreatine (fos-foh-kree--teen) n.

creatine phosphate (see CREATINE).

Back  -    New Search

phospholipid (fos-foh-lip-id) n.

a lipid containing a phosphate group as part of the molecule. Phospholipids are constituents of all tissues and organs, especially the brain. They are involved in many of the body's metabolic processes. Examples are cephalins, lecithins, and plasmalogens.

Back  -    New Search

phosphonecrosis (fos-foh-nek-roh-sis) n.

the destruction of tissues caused by excessive amounts of phosphorus in the system. The tissues likely to suffer are the liver, kidneys, muscles, bones, and the cardiovascular system.

Back  -    New Search

phosphorus (fos-fer-us) n.

a nonmetallic element that is toxic in its pure state. Phosphorus compounds are major constituents in the tissues of both plants and animals. In man, phosphorus is mostly concentrated in bone. Symbol: P.

Back  -    New Search

phot- (photo-) prefix

denoting light.

Back  -    New Search

photalgia (foh-tal-ji) n.

pain in the eye caused by very bright light.

Back  -    New Search

photoablation (foh-toh-b-lay-shn) n.

the use of light or lasers to destroy tissue.

Back  -    New Search

photochemotherapy (foh-toh-kee-moh-th'e-r-pi) n.

see PUVA.

Back  -    New Search

photocoagulation (foh-toh-koh-ag-yoo-lay-shn) n.

1 the destruction of tissue by heat released from the absorption of light shone on it. In eye disorders the technique is used to destroy diseased retinal tissue and to produce scarring between the retina and choroid, thus binding them together, in cases of retinal detachment.

2 a method of arresting bleeding by causing coagulation, usually using an infrared light source.
Top

Back  -    New Search

photodermatosis (foh-toh-der-m-toh-sis) n.

any of various diseases caused by exposure to light of varying wavelength (see PHOTOSENSITIVITY). The face and neck are most commonly affected. A common photodermatosis is polymorphic light eruption , which appears with the first sunshine of spring and abates by late summer. The photodermatoses include certain porphyrias and also photosensitivity reactions in those taking such drugs as tetracyclines, phenothiazines, frusemide, and NSAIDs.

Back  -    New Search

photomicrograph (foh-toh-my-kr-grahf) n.

see MICROGRAPH.

Back  -    New Search

photophobia (foh-toh-foh-bi) n.

an abnormal intolerance of light, in which exposure to light produces intense discomfort of the eyes with tight contraction of the eyelids. Photophobia may be associated with migraine, measles, German measles, or meningitis.

Back  -    New Search

photophthalmia (foh-tof-thal-mi) n.

inflammation of the eye due to exposure to light. It is usually caused by the damaging effect of ultraviolet light on the cornea, for example in snow blindness.

Back  -    New Search

photoretinitis (foh-toh-ret-in-I-tis) n.

damage to the retina of the eye caused by looking at the sun without adequate protection for the eyes. The central part of the visual field may be permanently lost (sun blindness ).

Back  -    New Search

photosensitivity (foh-toh-sen-si-tiv-iti) n.

abnormal reaction of the skin to sunlight. See also PHOTODERMATOSIS.
—photosensitive adj.

Back  -    New Search

phototherapy (foh-toh-th'e-r-pi) n.

the treatment of disorders by exposing the patient to light. Phototherapy using fluorescent light is used to treat jaundice in the newborn, as the blue range of the light decomposes bilirubin.

Back  -    New Search

photuria (foht-yoor-i) n.

the excretion of phosphorescent urine, due to the presence of certain compounds containing phosphorus.

Back  -    New Search

phren- (phreno-) prefix

denoting 1 the mind or brain.

2 the diaphragm.
Top

3 the phrenic nerve.
Top

Back  -    New Search

-phrenia suffix

denoting a condition of the mind.

Back  -    New Search

phrenic (fren-ik) adj.

1 relating to the mind.

2 relating to the diaphragm. p. avulsion the surgical removal of a section of the phrenic nerve, which paralyses the diaphragm. The procedure was used as a means of resting a lung infected with tuberculosis. p. crush surgical crushing of a portion of the phrenic nerve. This paralyses the diaphragm on the side operated upon, which is then pushed upwards by the abdominal contents, thus pressing on the lung and partially collapsing it. It was formerly used in the treatment of tuberculosis. p. nerve the nerve that supplies the muscles of the diaphragm. On each side it arises in the neck and passes downwards between the lungs and the heart.
Top

Back  -    New Search

phthalylsulphathiazole (thal-il-sul-f-th'y--zohl) n.

a drug (see SULPHONAMIDE) that is slowly broken down in the gut and is therefore administered by mouth to treat bowel infections.

Back  -    New Search

Phthirus (thi-rs) n.

a widely distributed genus of lice. P. pubis the crab (or pubic) louse, a common parasite of man that lives permanently attached to the body hair, particularly that of the pubic or perianal regions. See also PEDICULOSIS.

Back  -    New Search

phthisis (th'y-sis) n.

1 any disease resulting in wasting of tissues. p. bulbi a shrunken eyeball that has lost its function due to disease or damage.

2 a former name for pulmonary tuberculosis.
Top

Back  -    New Search

phycomycosis (fy-koh-my-koh-sis) n.

a disease caused by parasitic fungi of the genera Rhizopus, Absidia, and Mucor. The fungi grow within the blood vessels of the lungs and nervous tissue, causing blood clots that cut off the blood supply (see INFARCTION). Treatment with the antibiotic amphotericin B has proved effective.

Back  -    New Search

physi- (physio-) prefix

denoting 1 physiology.

2 physical.
Top

Back  -    New Search

physical (fiz-ikl) adj.

(in medicine) relating to the body rather than to the mind. p. sign a sign that a doctor can detect when examining a patient, such as abnormal dilation of the pupils or the absence of a knee-jerk reflex.

Back  -    New Search

physical medicine n.

the medical specialty concerned with the diagnosis and management of rheumatic diseases and the rehabilitation of patients with physical disabilities. See also RHEUMATOLOGY.

Back  -    New Search

physician (fiz-ish-n) n.

a registered medical practitioner who specializes in the diagnosis and treatment of disease by other than surgical means. See also DOCTOR.

Back  -    New Search

physiological saline (fiz-i--loj-ikl) n.

a 0.9% solution of sodium chloride in water, used for maintaining living cells.

Back  -    New Search

physiological solution n.

one of a group of solutions, including Ringer's solution, used to maintain tissues in a viable state. These solutions contain specific concentrations of substances that are vital for normal tissue function.

Back  -    New Search

physiology (fiz-i-ol-ji) n.

the science of the functioning of living organisms and of their component parts.
—physiological adj. —physiologist n.

Back  -    New Search

physiotherapy (fiz-i-oh-th'e-r-pi) n.

the branch of treatment that employs physical methods to promote healing, including the use of light, heat, electric current, massage, manipulation, and remedial exercise.

Back  -    New Search

physo- prefix

denoting air or gas.

Back  -    New Search

physostigmine (eserine) (fy-soh-stig-meen) n.

a parasympathomimetic drug used mainly to constrict the pupil of the eye and to reduce pressure inside the eye in glaucoma. It is administered by injection, in eye drops, or in an ointment.

Back  -    New Search

phyt- (phyto-) prefix

denoting plants; of plant origin.

Back  -    New Search

phytomenadione (fy-toh-men--dy-ohn) n.

a form of vitamin K that is used as an antidote to overdosage with anticoagulant drugs. It promotes the production of prothrombin, essential for the normal coagulation of blood. Trade name: Konakion .

Back  -    New Search

pia (pia mater) (pee-) n.

the innermost of the three meninges surrounding the brain and spinal cord. It contains numerous finely branching blood vessels that supply the nerve tissue within.

Back  -    New Search

pian (pi-ahn) n.

see YAWS.

Back  -    New Search

pica (py-k) n.

the indiscriminate eating of non-nutritious or harmful substances, such as grass, stones, or clothing. It is common in early childhood but may also be found in mentally handicapped and psychotic patients.

Back  -    New Search

Pick's disease (piks) n.

1 a rare cause of dementia in middle-aged people. The damage is mainly in the frontal and temporal lobes of the brain. [A. Pick (1851–1924), Czech psychiatrist]

2 a syndrome in constrictive pericarditis, in which there is hepatic enlargement, ascites, and pleural effusion. [F. Pick (1867–1926), Czech physician]
Top

Back  -    New Search

picornavirus (pi-kor-n-vy-rs) n.

one of a group of small RNA-containing viruses. The group includes Coxsackie viruses, polioviruses, and rhinoviruses.

Back  -    New Search

picric acid (trinitrophenol) (pik-rik) n.

a yellow crystalline solid used as a dye and as a tissue fixative.

Back  -    New Search

PID n.

1 see PELVIC INFLAMMATORY DISEASE.

2 see PROLAPSED INTERVERTEBRAL DISC.
Top

Back  -    New Search

Pierre Robin syndrome (p'yair roh-ban) n.

a congenital disease in which affected infants have a very small lower jawbone (mandible) and a cleft palate. They are susceptible to feeding and respiratory problems. [Pierre Robin (1867–1950), French dentist]

Back  -    New Search

piezoelectric (peets-oh-i-lek-trik) adj.

denoting or relating to an electrically generated pulse or polarity that is caused by pressure.

Back  -    New Search

pigeon chest (pij-n) n.

forward protrusion of the breastbone resulting in deformity of the chest. The condition is painless and harmless. Medical name: pectus carinatum .

Back  -    New Search

pigeon toes n.

an abnormal posture in which the toes are turned inwards. It is often associated with knock-knee.

Back  -    New Search

pigment (pig-mnt) n.

a substance giving colour. Physiologically important pigments include the blood pigments (especially haemoglobin), the bile pigments, and retinal pigment (see RHODOPSIN).

Back  -    New Search

pigmentation (pig-mn-tay-shn) n.

coloration produced in the body by the deposition of one pigment, especially in excessive amounts. Pigmentation may be produced by natural pigments, such as melanin, or by foreign material, such as lead or arsenic in chronic poisoning.

Back  -    New Search

PIH n.

pregnancy-induced hypertension. See PRE-ECLAMPSIA.

Back  -    New Search

piles (pylz) pl. n.

see HAEMORRHOIDS.

Back  -    New Search

pill (pil) n.

1 a small ball of variable size, shape, and colour, sometimes coated with sugar, that contains one or more medicinal substances in solid form. It is taken by mouth.

2 the Pill see ORAL CONTRACEPTIVE.
Top

Back  -    New Search

pillar (pil-er) n.

(in anatomy) an elongated apparently supportive structure.

Back  -    New Search

pilo- prefix

denoting hair.

Back  -    New Search

pilocarpine (py-loh-kar-peen) n.

a drug with actions and uses similar to those of physostigmine. It is administered as eye drops. Trade name: Minims pilocarpine .

Back  -    New Search

pilomotor nerves (py-loh-moh-ter) pl. n.

sympathetic nerves that supply muscle fibres in the skin, around the roots of hairs. Activity of the sympathetic nervous system causes the muscles to contract, resulting in goose flesh.

Back  -    New Search

pilonidal sinus (py-loh-ny-d'l) n.

a short tract leading from an opening in the skin in the cleft at the top of the buttocks and containing hairs. The sinus may be recurrently infected, leading to pain and the discharge of pus.

Back  -    New Search

pilosebaceous (py-loh-si-bay-shs) adj.

relating to the hair follicles and their associated sebaceous glands.

Back  -    New Search

pilosis (py-loh-sis) n.

the abnormal growth of hair.

Back  -    New Search

pilus (py-ls) n.

a hair.

Back  -    New Search

pimel- (pimelo-) prefix

denoting fat; fatty.

Back  -    New Search

pimozide (pim-oh-zyd) n.

an antipsychotic drug administered by mouth to relieve hallucinations and delusions occurring in schizophrenia. Trade name: Orap .

Back  -    New Search

pimple (pim-pl) n.

a small inflamed swelling on the skin that contains pus. It may be the result of bacterial infection of a skin pore that has become obstructed with fatty secretions from the sebaceous glands. See also ACNE.

Back  -    New Search

pineal gland (pineal body) (pin-i-l) n.

a pea-sized mass of nerve tissue attached by a stalk to the posterior wall of the third ventricle of the brain. It functions as a gland, secreting the hormone melatonin. Anatomical name: epiphysis .

Back  -    New Search

pinguecula (ping-wek-yoo-l) n.

a degenerative change in the conjunctiva of the eye, seen most commonly in the elderly. Thickened yellow triangles develop on the conjunctiva at the inner and outer margins of the cornea.

Back  -    New Search

pink disease n.

a severe illness of children of the teething age, marked by pink cold clammy hands and feet, heavy sweating, raised blood pressure, rapid pulse, and photophobia. Affected infants are very prone to secondary infection, which may be fatal. The condition may be an allergic reaction to mercury; it has virtually disappeared since all mercury-containing paediatric preparations have been banned. Medical names: acrodynia , erythroedema , erythromelalgia .

Back  -    New Search

pink eye n.

see CONJUNCTIVITIS.

Back  -    New Search

pinna (auricle) (pin-) n.

the flap of skin and cartilage that projects from the head at the exterior opening of the external auditory meatus of the ear.

Back  -    New Search

pinnaplasty (pin--plasti) n.

see OTOPLASTY.

Back  -    New Search

pinocytosis (pee-noh-sy-toh-sis) n.

the intake of small droplets of fluid by a cell by cytoplasmic engulfment. Compare PHAGOCYTOSIS.

Back  -    New Search

pins and needles (pinz) pl. n.

see PARAESTHESIAE.

Back  -    New Search

pinta (pin-t) n.

a skin disease, prevalent in tropical America, that seems to affect only the dark-skinned races. It is caused by the spirochaete Treponema carateum. Symptoms include thickening and eventual loss of pigment of the skin, particularly on the hands, wrists, feet, and ankles.

Back  -    New Search

pinworm (pin-werm) n.

see THREADWORM.

Back  -    New Search

piperazine (pi-pe-r-zeen) n.

a drug that is administered by mouth to treat infestations by roundworms and threadworms. Trade name: Pripsen .

Back  -    New Search

piriform fossae (pi-ri-form) pl. n.

two pear-shaped depressions that lie on either side of the opening to the larynx.

Back  -    New Search

piroxicam (py-roks-i-kam) n.

a non-steroidal anti-inflammatory drug (see NSAID) administered by mouth to relieve pain and stiffness in osteoarthritis, rheumatoid arthritis, gout, and ankylosing spondylitis. Trade name: Feldene .

Back  -    New Search

Pls pl. n.

see PERFORMANCE INDICATORS.

Back  -    New Search

pisiform bone (py-si-form) n.

the smallest bone of the wrist (see CARPUS): a pea-shaped bone that articulates with the triquetral bone and, indirectly by cartilage, with the ulna.

Back  -    New Search

pit (pit) n.

(in anatomy) a hollow or depression.

Back  -    New Search

pithiatism (pith-I--tizm) n.

the treatment of certain disorders by persuading the patient that all is well.

Back  -    New Search

pitting (pit-ing) n.

the formation of depressed scars, as occurs on the skin following acne. p. oedema oedema in which fingertip pressure leaves temporary indentations in the skin.

Back  -    New Search

pituitary gland (hypophysis) (pit-yoo-it-eri) n.

the master endocrine gland: a pea-sized body attached to the hypothalamus at the base of the skull. The anterior lobe of the gland (adeno-hypophysis ) secretes thyroid-stimulating hormone, ACTH, gonadotrophins (LH and FSH), growth hormone, prolactin, lipotrophin, and melanocyte-stimulating hormone. The posterior lobe (neuro-hypophysis ) secretes vasopressin and oxytocin.

Back  -    New Search

pityriasis (pit-i-ry--sis) n.

(originally) any of a group of skin diseases typified by the development of fine branlike scales. p. alba a common condition in children in which pale scaly patches occur on the face. p. capitis see DANDRUFF. p. rosea a common skin rash, believed to be viral in origin, that starts with a single patch of spots on the trunk and is followed by an eruption of oval pink scaly macules. The rash clears completely in about eight weeks. p. versicolor a common chronic infection of the skin caused by the fungus Pityrosporum orbiculare, a normal inhabitant of the scalp that in susceptible people changes to a pathogenic form on the trunk.

Back  -    New Search

Pityrosporum (pit-i-ros-p-rm) n.

a genus of yeasts producing superficial infections of the skin. P. orbiculare a normal inhabitant of the scalp that can become pathogenic in susceptible individuals (see PITYRIASIS).

Back  -    New Search

pivampicillin (piv-am-pi-sil-in) n.

a broad-spectrum penicillin-type antibiotic administered by mouth to treat bronchitis, pneumonia, skin infections, urinary infections, and gonorrhoea. Trade name: Pondocillin .

Back  -    New Search

pivmecillinam (piv-mes-il-in-am) n.

a penicillin-type antibiotic used to treat urinary-tract and other infections. It is administered by mouth. Trade name: Selexid .

Back  -    New Search

pivot joint (piv-t) n.

see TROCHOID JOINT.

Back  -    New Search

pizotifen (piz-ot-i-fen) n.

an antihistamine drug used to prevent severe migraine attacks. Administered by mouth, it acts by inhibiting the effects of serotonin. Trade name: Sanomigran .

Back  -    New Search

placebo (pl-see-boh) n.

a medicine that is ineffective but may help to relieve a condition because the patient has faith in its powers. New drugs are tested against placebos in clinical trials.

Back  -    New Search

placenta (pl-sent-) n.

an organ within the uterus by means of which the embryo is attached to the wall of the uterus. Its primary function is to provide the embryo with nourishment, eliminate its wastes, and exchange respiratory gases. It also functions as a gland, secreting chorionic gonadotrophin, progesterone, and oestrogens. See also AFTERBIRTH. p. praevia a placenta situated wholly or partially in the lower and noncontractile part of the uterus. When this becomes elongated and stretched during the last few weeks of pregnancy, and the cervix becomes stretched either before or during labour, placental separation and haemorrhage will occur. If the placenta is situated entirely before the presenting part of the fetus, delivery must be by Caesarean section.
—placental adj.

Back  -    New Search

placentography (plas-en-tog-rfi) n.

radiography of the pregnant uterus in order to determine the position of the placenta. This method is now superseded by the use of ultrasound.

Back  -    New Search

plagiocephaly (play-ji-oh-sef-li) n.

any distortion or lack of symmetry in the shape of the head, usually due to irregularity in the closure of the sutures between the bones of the skull.

Back  -    New Search

plague (playg) n.

1 any epidemic disease with a high death rate.

2 an acute epidemic disease of rats and other wild rodents caused by the bacterium Yersinia pestis, which is transmitted to man by rat fleas. bubonic p. the most common form of the disease, characterized by acute painful swellings of the lymph nodes (see BUBO). In favourable cases the buboes burst and then heal; in other cases bleeding under the skin can lead to ulcers, which may prove fatal. pneumonic p. a serious form of plague in which the lungs are affected. septicaemic p. a serious form of plague in which bacteria enter the bloodstream.
Top

Back  -    New Search

plane (playn) n.

a level or smooth surface, especially any of the hypothetical flat surfaces used to divide the body (see CORONAL, SAGITTAL).

Back  -    New Search

planning (plan-ing) n.

the stage of the nursing process in which an individual care plan is produced, stating the patient's problem(s), the objective, the goal or expected outcome, the nursing intervention, and the time or date by which the objective is expected to be achieved or by which the problem should be reviewed.

Back  -    New Search

plantar (plan-ter) adj.

relating to the sole of the foot (planta ). p. arch the arch in the sole of the foot formed by anastomosing branches of the plantar arteries. p. fasciitis (policeman's heel ) inflammation of the point of attachment of the fascia in the sole of the foot to the calcaneus, causing pain and tenderness of the heel. p. reflex a reflex obtained by drawing a bluntly pointed object along the outer border of the sole of the foot. The normal response is a bunching and downward movement of the toes. Compare BABINSKI REFLEX. p. wart see WART.

Back  -    New Search

plaque (plak) n.

1 a layer composed of bacteria in an organic matrix that forms on the surface of a tooth, principally at its neck. It may cause caries or periodontal disease.

2 a raised patch on the skin formed by enlarging or coalescing papules.
Top

3 a deposit, consisting of a fatty core covered with a fibrous cap, that develops on the inner wall of an atheromatous artery.
Top

4 any flattened patch or localized area of abnormality on a body surface.
Top

Back  -    New Search

-plasia suffix

denoting formation; development.

Back  -    New Search

plasm- (plasmo-) prefix

denoting 1 blood plasma.

2 protoplasm or cytoplasm.
Top

Back  -    New Search

plasma (blood plasma) (plaz-m) n.

the straw-coloured fluid in which the blood cells are suspended. It consists of a solution of various inorganic salts of sodium, potassium, calcium, etc., with a high concentration of protein and a variety of trace substances.

Back  -    New Search

plasma cells pl. n.

antibody-producing cells found in bone-forming tissue and also in the epithelium of the lungs and gut. They develop in the bone marrow, lymph nodes, and spleen when antigens stimulate B-lymphocytes to produce the precursor cells that give rise to them.

Back  -    New Search

plasmacytoma (plaz-m-sy-toh-m) n.

a malignant tumour of plasma cells, usually occurring as a single tumour in bone marrow and often known as a ‘solitary myeloma’. However, it may be multiple, in which case it is classified as a multiple myeloma.

Back  -    New Search

plasmapheresis (plaz-m-fer-ee-sis) n.

a method of removing a quantity of plasma from the blood. Blood is withdrawn from the patient and allowed to settle. The plasma is then drawn off and the blood cells transfused back into the patient.

Back  -    New Search

plasmin (fibrinolysin) (plaz-min) n.

an enzyme that digests the protein fibrin. Its function is the dissolution of blood clots (see FIBRINOLYSIS).

Back  -    New Search

plasminogen (plaz-min--jn) n.

a substance normally present in the blood plasma that may be activated to form plasmin. See FIBRINOLYSIS, TISSUE PLASMINOGEN ACTIVATOR.

Back  -    New Search

Plasmodium (plaz-moh-dim) n.

a genus of protozoans (see SPOROZOA) that live as parasites within the red blood cells and liver cells of man. Four species cause malaria in man: P. vivax, P. ovale, P. falciparum, and P. malariae.

Back  -    New Search

plaster (plah-ster) n.

adhesive tape used in shaped pieces or as a bandage to keep a dressing in place.

Back  -    New Search

plaster of Paris n.

a preparation of gypsum (calcium sulphate) that sets hard when water is added. It is used in dentistry and orthopaedics for preparing plaster casts.

Back  -    New Search

plastic lymph (plast-ik) n.

a transparent yellowish liquid produced in a wound or other site of inflammation, in which connective tissue cells and blood vessels develop during healing.

Back  -    New Search

plastic surgery n.

a branch of surgery dealing with the reconstruction of parts of the body deformed or damaged by burns, major accidents, or cancer. It also includes the correction of congenital defects, such as cleft lip, and the replacement of parts of the body that have been lost.

Back  -    New Search

plastron (plas-tron) n.

the breastbone (sternum) together with the costal cartilages attached to it.

Back  -    New Search

-plasty suffix

denoting plastic surgery.

Back  -    New Search

platelet (thrombocyte) (playt-lit) n.

a disc-shaped cell structure, 1–2 µm in diameter, present in the blood. Platelets have several functions, all relating to the arrest of bleeding (see BLOOD COAGULATION). See also THROMBOPOIESIS.

Back  -    New Search

platy- prefix

denoting broad or flat.

Back  -    New Search

platyhelminth (plat-i-hel-minth) n.

see FLATWORM.

Back  -    New Search

platysma (pl-tiz-m) n.

a broad thin sheet of muscle that extends from below the collar bone to the angle of the jaw. It depresses the jaw.

Back  -    New Search

pledget (plej-it) n.

a small wad of dressing material, such as lint, used either to cover a wound or sore or as a plug. Mounted on an instrument, it is used during operations to wipe away blood and other fluids.

Back  -    New Search

-plegia suffix

denoting paralysis.

Back  -    New Search

pleio- (pleo-) prefix

denoting 1 multiple.

2 excessive.
Top

Back  -    New Search

pleocytosis (plee-oh-sy-toh-sis) n.

the presence of an abnormally large number of lymphocytes in the cerebrospinal fluid.

Back  -    New Search

pleomorphism (plee-oh-mor-fizm) n.

the condition in which an individual assumes a number of different forms during its life cycle. The malarial parasite (Plasmodium) displays pleomorphism.

Back  -    New Search

pleoptics (plee-op-tiks) n.

special techniques practised by orthoptists for developing normal function of the macula, in people whose macular function has previously been disturbed because of strabismus (squint).

Back  -    New Search

plessor (plexor) (ples-er) n.

a small hammer used to investigate nervous reflexes and in the technique of percussion.

Back  -    New Search

plethora (pleth-er-) n.

any excess of any bodily fluid, especially blood (see HYPERAEMIA).
—plethoric (pleth-o-rik) adj.

Back  -    New Search

plethysmography (pleth-iz-mog-rfi) n.

the process of recording the changes in the volume of a limb caused by alterations in blood pressure. The limb is inserted into a fluid-filled watertight casing (oncometer ) and the pressure variations in the fluid are recorded.

Back  -    New Search

pleur- (pleuro-) prefix

denoting 1 the pleura.

2 the side of the body.
Top

Back  -    New Search

pleura (ploor-) n.

the covering of the lungs (visceral p. ) and of the inner surface of the chest wall (parietal p. ), consisting of a closed sac of serous membrane. Fluid secreted by the membrane lubricates the opposing surfaces so that they can slide painlessly over each other during breathing.

—pleural adj.

Back  -    New Search

pleural cavity (ploor-l) n.

the space between the visceral and parietal pleura, which is normally very small as the pleural membranes are in close contact.

Back  -    New Search

pleurectomy (ploor-ek-tmi) n.

surgical removal of part of the pleura, which is sometimes done to prevent further recurrences of spontaneous pneumothorax or to remove diseased areas of pleura.

Back  -    New Search

pleurisy (ploor-i-si) n.

inflammation of the pleura, often due to pneumonia in the underlying lung. The pleural surfaces become slightly sticky, so that there is pain on deep breathing. Pleurisy is always associated with some other disease in the lung, chest wall, diaphragm, or abdomen.

Back  -    New Search

pleurocele (ploor-oh-seel) n.

herniation of the pleura.

Back  -    New Search

pleurocentesis (thoracentesis, thoracocentesis) (ploor-oh-sen-tee-sis) n.

the insertion of a hollow needle into the pleural cavity through the chest wall in order to withdraw fluid, blood, pus, or air.

Back  -    New Search

pleurodesis (ploor-oh-dee-sis) n.

a treatment for pneumothorax in which adhesions between the parietal and visceral pleura are induced by injecting a substance (e.g. silver nitrate) into the pleural cavity.

Back  -    New Search

pleurodynia (ploor-oh-din-i) n.

severe paroxysmal pain arising from the muscles between the ribs. It is often thought to be of rheumatic origin.

Back  -    New Search

pleurolysis (pneumolysis) (ploor-ol-i-sis) n.

surgical stripping of the parietal pleura from the chest wall to allow the lung to collapse. The procedure was formerly used to help tuberculosis to heal.

Back  -    New Search

pleuropneumonia (ploor-oh-new-moh-ni) n.

inflammation involving both the lung and pleura. See PLEURISY, PNEUMONIA.

Back  -    New Search

pleuropneumonia-like organisms (PPLO) pl. n.

see MYCOPLASMA.

Back  -    New Search

plexor (pleks-er) n.

see PLESSOR.

Back  -    New Search

plexus (pleks-s) n.

a network of nerves or blood vessels. See BRACHIAL PLEXUS.

Back  -    New Search

PLF n.

(serum) placental fementin: a storage protein, levels of which are used for monitoring placental function from conception until delivery.

Back  -    New Search

plica (plik-) n.

a fold of tissue.
—plicate adj.

Back  -    New Search

plicamycin (plik--my-sin) n.

see MITHRAMYCIN.

Back  -    New Search

plication (pli-kay-shn) n.

a surgical technique in which the size of a hollow organ is reduced by taking tucks or folds in the walls.

Back  -    New Search

ploidy (ployd-i) n.

the condition of having multiple the normal number of chromosomes for the species. An increase in ploidy in the cells of a malignant tumour usually indicates greater aggressiveness and ability to invade.

Back  -    New Search

plombage (plom-bahzh) n.

a surgical technique used to correct retinal detachment. A small piece of silicone plastic is sewn on the outside of the eyeball to produce an indentation over the retinal hole or tear to allow the retina to reattach.

Back  -    New Search

plumbism (plum-bizm) n.

lead poisoning. See LEAD.

Back  -    New Search

Plummer-Vinson syndrome (plum-er vin-sn) n.

a disorder characterized by difficulty in swallowing associated with severe iron-deficiency anaemia. [H. S. Plummer (1874–1936) and P. P. Vinson (1890–1959), US physicians]

Back  -    New Search

pluri- prefix

denoting more than one; several.

Back  -    New Search

pneo- prefix

denoting breathing; respiration.

Back  -    New Search

pneum- (pneumo-) prefix

denoting 1 the presence of air or gas.

2 the lung(s).
Top

3 respiration.
Top

Back  -    New Search

pneumat- (pneumato-) prefix

denoting 1 the presence of air or gas.

2 respiration.
Top

Back  -    New Search

pneumatocele (new-mat-oh-seel) n.

herniation of lung tissue.

Back  -    New Search

pneumatosis (new-m-toh-sis) n.

the occurrence of gas cysts in abnormal sites in the body. p. cystoides intestinalis the occurrence of multiple gas cysts in the walls of the lower intestines.

Back  -    New Search

pneumaturia (new-mt-yoor-i) n.

the presence in the urine of bubbles of air or other gas, due to the formation of gas by bacteria infecting the urinary tract or to a fistula between the urinary tract and bowel.

Back  -    New Search

pneumocephalus (pneumocele) (new-moh-sef--ls) n.

the presence of air within the skull, usually resulting from a fracture passing through one of the air sinuses.

Back  -    New Search

pneumococcus (new-moh-kok-s) n. (pl. pneumococci)

the bacterium Streptococcus pneumoniae, which is associated with pneumonia.
—pneumococcal adj.

Back  -    New Search

pneumoconiosis (new-moh-koh-ni-oh-sis) n.

a group of lung diseases caused by inhaling dust. In practice industrial exposure to coal dust (see COAL-WORKER'S PNEUMOCONIOSIS), silica (see SILICOSIS), and asbestos (see ASBESTOSIS) produces most of the cases of pneumoconiosis.

Back  -    New Search

Pneumocystis (new-moh-sis-tis) n.

a genus of protozoans. P. carinii the cause of pneumonia in immunosuppressed patients, usually following intensive chemotherapy or in patients with AIDS. See also OPPORTUNISTIC.

Back  -    New Search

pneumocyte (new-moh-syt) n.

a type of cell that lines the walls separating the air sacs (see ALVEOLUS) in the lungs.

Back  -    New Search

pneumoencephalography (new-moh-en-sef--log-rfi) n.

a technique used in the X-ray diagnosis of disease within the skull. Air is introduced into the ventricles of the brain to displace the cerebrospinal fluid, thus acting as a contrast medium. X-ray photographs show the size and disposition of the ventricles and the subarachnoid spaces. The technique has largely been superseded by CT and MRI scanning.

Back  -    New Search

pneumogastric (new-moh-gas-trik) adj.

relating to the lungs and stomach. p. nerve the vagus nerve.

Back  -    New Search

pneumograph (new-moh-grahf) n.

an instrument used to record the movements made during respiration.

Back  -    New Search

pneumolysis (new-mol-i-sis) n.

see PLEUROLYSIS.

Back  -    New Search

pneumomycosis (new-moh-my-koh-sis) n.

any infection of the lungs caused by fungi, such as aspergillosis.

Back  -    New Search

pneumon- (pneumono-) prefix

denoting the lung(s).

Back  -    New Search

pneumonectomy (new-m-nek-tmi) n.

surgical removal of a lung, usually for cancer.

Back  -    New Search

pneumonia (new-moh-ni) n.

inflammation of the lung caused by bacteria, in which the alveoli become filled with inflammatory cells and the lung becomes solid (see CONSOLIDATION). The symptoms include fever, malaise, cough, and chest pain, and there are shadows on the chest X-ray. Treatment with antibiotics is usually effective. bronchopneumonia pneumonia that starts in the small bronchi and spreads into the alveoli. hypostatic p. pneumonia that develops in dependant parts of the lung in people who are otherwise ill, chilled, or immobilized. lobar p. pneumonia that affects whole lobes of either or both lungs. See also ATYPICAL (PNEUMONIA), VIRAL PNEUMONIA. Compare PNEUMONITIS.

Back  -    New Search

pneumonitis (new-m-ny-tis) n.

inflammation of the lung that is confined to the walls of the alveoli and often caused by viruses or unknown agents. It may be acute and transient or chronic, leading to increasing respiratory disability. It does not respond to antibiotics but corticosteroids may be helpful. Compare PNEUMONIA.

Back  -    New Search

pneumoperitoneum (new-moh-pe-ri-tn-ee-m) n.

air or gas in the peritoneal or abdominal cavity, usually due to a perforation of the stomach or bowel. It may be induced for diagnostic purposes (see LAPAROSCOPY).

Back  -    New Search

pneumoradiography (new-moh-ray-di-og-rfi) n.

X-ray examination of part of the body using a gas, such as air or carbon dioxide, as a contrast medium. The technique is now little used.

Back  -    New Search

pneumoretinopexy (new-moh-ret-in-oh-pek-si) n.

a surgical technique in which an inert gas bubble is injected into the eye to press and seal breaks in the retina. When the retina is flat, a laser beam or cryoretinopexy is applied to cause scarring and permanently seal the tear.

Back  -    New Search

pneumothorax (new-moh-thor-aks) n.

air in the pleural cavity, which results from breach of the lung surface or chest wall and causes the lung to collapse. artificial p. the deliberate injection of air into the pleural cavity to collapse the lung: a former treatment for pulmonary tuberculosis. spontaneous p. pneumothorax that occurs without any apparent cause, in otherwise healthy people. tension p. pneumothorax in which a breach in the lung surface acts as a valve, admitting air into the pleural cavity when the patient breathes in but preventing its escape when he breathes out. traumatic p. pneumothorax that results from injuries to the chest.

Back  -    New Search

pneumotonometer (new-moh-toh-nom-it-er) n.

an instrument that blows a puff of air at the cornea to cause flattening and hence measure intraocular pressure. It is commonly used by optometrists in tests for glaucoma.

Back  -    New Search

-pnoea suffix

denoting a condition of breathing.

Back  -    New Search

pock (pok) n.

a small pus-filled eruption on the skin characteristic of chickenpox and smallpox rashes. See also PUSTULE.

Back  -    New Search

pod- prefix

denoting the foot.

Back  -    New Search

podagra (p-dag-r) n.

gout of the foot, especially the big toe.

Back  -    New Search

podalic version (p-dal-ik) n.

altering the position of a fetus in the uterus so that its feet will emerge first at birth. See also VERSION.

Back  -    New Search

podopompholyx (poh-doh-pom-foh-liks) n.

see POMPHOLYX.

Back  -    New Search

-poiesis suffix

denoting formation; production.

Back  -    New Search

poikilo- prefix

denoting variation; irregularity.

Back  -    New Search

poikilocyte (poi-kil-oh-syt) n.

an abnormally shaped erythrocyte. See also POIKILOCYTOSIS.

Back  -    New Search

poikilocytosis (poi-kil-oh-sy-toh-sis) n.

the presence of poikilocytes in the blood. Poikilocytosis is particularly marked in myelofibrosis but can occur to some extent in almost any blood disease.

Back  -    New Search

poikilothermic (poi-kil-oh-therm-ik) adj.

cold-blooded: being unable to regulate the body temperature, which fluctuates according to that of the surroundings. Compare HOMOIOTHERMIC.
—poikilothermy n.

Back  -    New Search

poison (poi-zn) n.

any substance that irritates, damages, or impairs the activity of the body's tissues. The term is usually reserved for substances, such as arsenic, cyanide, and strychnine, that are harmful in relatively small amounts.

Back  -    New Search

polar body (poh-ler) n.

one of the small cells produced by division of an oocyte that does not develop into a functional egg cell. See OOGENESIS.

Back  -    New Search

poldine (pol-deen) n.

a drug, similar to atropine, that inhibits gastric secretion and is administered by mouth to treat such disorders as gastric and duodenal ulcers. Trade name: Nacton .

Back  -    New Search

pole (pohl) n.

(in anatomy) the extremity of the axis of the body, an organ, or a cell.

Back  -    New Search

poli- (polio-) prefix

denoting the grey matter of the nervous system.

Back  -    New Search

policeman's heel (p-lees-mnz) n.

see PLANTAR (FASCIITIS).

Back  -    New Search

polioencephalitis (poh-li-oh-en-sef--ly-tis) n.

a virus infection of the brain, causing particular damage to the grey matter of the cerebral hemispheres and the brainstem. The term is now usually restricted to infections of the brain by the poliomyelitis virus.

Back  -    New Search

polioencephalomyelitis (poh-li-oh-en-sef--loh-my--ly-tis) n.

any virus infection of the central nervous system affecting the grey matter of the brain and spinal cord. Rabies is the outstanding example.

Back  -    New Search

poliomyelitis (infantile paralysis, polio) (poh-li-oh-my--ly-tis) n.

an infectious virus disease affecting the central nervous system. Immunization, using the Sabin vaccine or the Salk vaccine, is highly effective. abortive p. poliomyelitis in which only the throat and intestines are infected and the symptoms are those of a stomach upset or influenza. bulbar p. paralytic poliomyelitis in which the muscles of the respiratory system are affected. nonparalytic p. a form of the disease in which the symptoms of abortive poliomyelitis are accompanied by muscle stiffness. paralytic p. a less common form of polio in which the symptoms of the milder forms of the disease are followed by weakness and eventual paralysis of the muscles.

Back  -    New Search

poliovirus (poh-li-oh-vy-rs) n.

one of a small group of RNA-containing viruses causing poliomyelitis. They are included within the picornavirus group.

Back  -    New Search

Politzer's bag (pol-it-zerz) n.

a flexible rubber bag for inflating the middle ear through the Eustachian tube. [A. Politzer (1835–1920), Austrian otologist]

Back  -    New Search

pollex (pol-eks) n. (pl. pollices)

the thumb.

Back  -    New Search

pollinosis (poli-noh-sis) n.

a more precise term than hay fever for an allergy due to the pollen of grasses, trees, or shrubs.

Back  -    New Search

poly- prefix

denoting 1 many; multiple.

2 excessive.
Top

3 generalized; affecting many parts.
Top

Back  -    New Search

polyarteritis nodosa (periarteritis nodosa) (poli-ar-ter-I-tis noh-doh-s) n.

a disease of unknown cause in which there is patchy inflammation of the walls of the arteries. It is one of the connective-tissue diseases. Common manifestations include arthritis, skin rashes, asthma, hypertension, and kidney failure.

Back  -    New Search

polyarthritis (poli-arth-ry-tis) n.

rheumatic disease involving several joints, either together or in sequence, causing pain, stiffness, swelling, tenderness, and loss of function. Rheumatoid arthritis is the most common cause.

Back  -    New Search

polycystic disease of the kidneys (poli-sis-tik) n.

an inherited disorder in which the substance of both kidneys is largely replaced by numerous cysts. Symptoms, including haematuria, urinary tract infection, and hypertension, are associated with chronic kidney failure.

Back  -    New Search

polycystic ovary syndrome (POS) n.

a hormonal disorder characterized by incomplete development of Graafian follicles in the ovary due to inadequate secretion of luteinizing hormone; the follicles fail to ovulate and remain as multiple cysts distending the ovary. See also STEIN-LEVENTHAL SYNDROME.

Back  -    New Search

polycythaemia (poli-sy-theem-i) n.

an increase in the haemoglobin concentration of the blood. This may be due either to a decrease in the total volume of the plasma (relative p. ) or to an increase in the total volume of the red cells (absolute p. ). The latter may occur as a primary disease or as a secondary condition in association with various respiratory or circulatory disorders and with certain tumours. p. vera (p. rubra vera , erythraemia , Vaques-Osler disease ) a disease in which absolute polycythaemia is often accompanied by an increase in the numbers of white blood cells and platelets. Symptoms include headache, thromboses, cyanosis, plethora, and itching.

Back  -    New Search

polydactylism (poli-dak-til-izm) n.

see HYPERDACTYLISM.

Back  -    New Search

polydipsia (poli-dip-si) n.

abnormally intense thirst: a symptom of diabetes mellitus and diabetes insipidus.

Back  -    New Search

polymer (pol-im-er) n.

a substance formed by the linkage of a large number of smaller molecules known as monomers . An example of a monomer is glucose, whose molecules link together to form glycogen, a polymer.

Back  -    New Search

polymorph (polymorphonuclear leucocyte) (pol-i-morf) n.

see NEUTROPHIL.

Back  -    New Search

polymorphic light eruption (poli-mor-fik) n.

see PHOTODERMATOSIS.

Back  -    New Search

polymyalgia rheumatica (poli-my-al-ji roo-mat-ik) n.

a rheumatic disease causing aching and progressive stiffness of the muscles of the shoulders and hips. It is typically associated with loss of appetite, fatigue, night sweats, and a raised ESR. The condition is most common in the elderly and is often associated with temporal arteritis. The symptoms respond rapidly and effectively to corticosteroid treatment.

Back  -    New Search

polymyositis (poli-my-oh-sy-tis) n.

a generalized disease of the muscles that may be acute or chronic. It particularly affects the muscles of the shoulder and hip girdles, which are weak and tender to the touch. Relief of the symptoms is obtained with corticosteroid drugs. See also DERMATOMYOSITIS.

Back  -    New Search

polymyxin B (poli-miks-in) n.

an antibiotic used to treat severe infections caused by Gram-negative bacteria. It is administered as a solution or ointment for ear and eye infections, often formulated with other drugs.

Back  -    New Search

polyneuritis (poli-newr-l-tis) n.

a disorder involving several of the peripheral nerves, usually in a symmetrical distribution. The term is often used interchangeably with polyneuropathy although its specific use implies inflammation of the nerves.

Back  -    New Search

polyneuropathy (poli-newr-op--thi) n.

a disease involving multiple peripheral nerves. The symptoms first affect the tips of the fingers and toes and subsequently spread towards the trunk. See also GUILLAIN-BARRÉ SYNDROME (POSTINFECTIVE POLYNEUROPATHY), NEUROPATHY.

Back  -    New Search

polyopia (poli-oh-pi) n.

the sensation of multiple images of one object. It is sometimes experienced by people with early cataract. See also DIPLOPIA.

Back  -    New Search

polyp (polypus) (pol-ip) n.

a growth, usually benign, protruding from a mucous membrane. Polyps are commonly found in the nose and sinuses, giving rise to obstruction, chronic infection, and discharge. Other sites include the ear, the stomach, and the colon, where they may eventually become malignant. Polyps are usually removed surgically (see POLYPECTOMY). juvenile p. a polyp that occurs in the intestine (usually colon or rectum) of infants or young people; sometimes they are multiple (see POLYPOSIS). Most juvenile polyps are benign. See also PEUTZ-JEGHERS SYNDROME.

Back  -    New Search

polypectomy (poli-pek-tmi) n.

the surgical removal of a polyp. The technique used depends upon the site and size of the polyp, but it is often done by cutting across the base using a wire loop (snare) through which is passed a coagulating diathermy current.

Back  -    New Search

polypeptide (poli-pep-tyd) n.

a molecule consisting of three or more amino acids linked together by peptide bonds. Protein molecules are polypeptides.

Back  -    New Search

polyphagia (poli-fay-ji) n.

gluttonous excessive eating.

Back  -    New Search

polypharmacy (poli-farm--si) n.

treatment of a patient with more than one type of medicine.

Back  -    New Search

polyploid (pol-i-ploid) adj.

describing cells, tissues, or individuals in which there are three or more complete sets of chromosomes. Compare DIPLOID, HAPLOID.
—polyploidy n.

Back  -    New Search

polypoid (pol-i-poid) adj.

having the appearance of a polyp.

Back  -    New Search

polyposis (poli-poh-sis) n.

a condition in which numerous polyps form in an organ or tissue. familial adenomatous p. (p. coli) a hereditary disease in which multiple adenomas develop in the gastrointestinal tract, usually the colon or rectum, at an early age. As these polyps invariably become malignant, patients are usually advised to undergo total removal of the affected bowel. See also PEUTZ-JEGHERS SYNDROME. Compare PSEUDOPOLYPOSIS.

Back  -    New Search

polypus (pol-i-ps) n.

see POLYP.

Back  -    New Search

polyradiculitis (polyradiculopathy) (poli-r-dik-yoo-ly-tis) n.

any disorder of the peripheral nerves (see NEUROPATHY) in which the brunt of the disease falls on the nerve roots where they emerge from the spinal cord.

Back  -    New Search

polysaccharide (poli-sak-eryd) n.

a carbohydrate formed from many monosaccharides joined together in long linear or branched chains. Examples are glycogen and cellulose.

Back  -    New Search

polyserositis (poli-seer-oh-sy-tis) n.

inflammation of the membranes that line the chest, abdomen, and joints, with accumulation of fluid in the cavities.

Back  -    New Search

polysomnograph (poli-som-noh-graf) n.

a record of measurements of various bodily parameters during sleep. It is used in the diagnosis of sleep disorders, such as obstructive sleep apnoea.

Back  -    New Search

polyspermia (poli-sper-mi) n.

1 excessive formation of semen.

2 see POLYSPERMY.
Top

Back  -    New Search

polyspermy (polyspermia) (poli-sper-mi) n.

fertilization of a single ovum by more than one spermatozoon: the development is abnormal and the embryo dies.

Back  -    New Search

polyuria (poli-yoor-i) n.

the production of large volumes of dilute urine. The phenomenon may be due simply to excessive liquid intake or to disease, particularly diabetes mellitus, diabetes insipidus, and kidney disorders.

Back  -    New Search

pompholyx (pom-foh-liks) n.

eczema of the hands (cheiropompholyx ) and feet (podopompholyx ). Because the horny layer of the skin in these parts is so thick the vesicles typical of eczema cannot rupture. There is intense itching until the skin eventually peels. Pompholyx is commonest in early adulthood.

Back  -    New Search

pons (ponz) n.

any portion of tissue that joins two parts of an organ. p. Varolii the part of the brainstem that links the medulla oblongata and the thalamus. It contains numerous nerve tracts between the cerebral cortex and the spinal cord. [C. Varolius (1543–75), Italian anatomist]
—pontine (pon-teen) adj.

Back  -    New Search

popliteus (pop-lit-is) n.

a flat triangular muscle at the back of the knee joint, between the femur and tibia, that helps to flex the knee.
—popliteal adj.

Back  -    New Search

pore (por) n.

a small opening. sweat p. the opening of a sweat gland on the surface of the skin.

Back  -    New Search

porencephaly (por-en-sef-li) n.

an abnormal communication between the lateral ventricle and the surface of the brain. This is usually a consequence of brain injury or cerebrovascular disease.

Back  -    New Search

porphin (por-fin) n.

a complex nitrogen-containing ring structure and parent compound of the porphyrins.

Back  -    New Search

porphyria (por-fi-ri) n.

one of a group of rare inborn errors of metabolism in which there are deficiencies in the enzymes involved in the biosynthesis of haem. The accumulation of the enzyme's substrate gives rise to the features of the disorder, which include the excretion of porphyrins and their derivatives in the urine, which may change colour on standing. acute intermittent p. a hereditary hepatic porphyria marked by recurrent attacks of acute abdominal pain, constipation, and psychotic behaviour. erythropoietic p. any porphyria in which the defect is primarily in the bone marrow. hepatic porphyria any porphyria in which the defect is primarily in the liver. p. cutanea tarda a hereditary or acquired hepatic porphyria in which light-exposed areas of the skin become blistered and fragile (see PHOTODERMATOSIS).

Back  -    New Search

porphyrin (por-fi-rin) n.

one of a number of pigments derived from porphin, which are widely distributed in living things. All porphyrins form chelates with iron, magnesium, zinc, nickel, copper, and cobalt. These chelates are constituents of haemoglobin, myohaemoglobin, the cytochromes, and chlorophyll. See also PROTOPORPHYRIN IX.

Back  -    New Search

porphyrinuria (por-fi-rin-yoor-i) n.

the presence in the urine of porphyrins, sometimes causing discoloration. See PORPHYRIA.

Back  -    New Search

porta (por-t) n.

the aperture in an organ through which its associated vessels pass. Such an opening occurs in the liver (p. hepatis )
—portal adj.

Back  -    New Search

portacaval anastomosis (portacaval shunt) (por-t-kay-vl) n.

1 a surgical technique in which the hepatic portal vein is joined to the inferior vena cava, thus bypassing the liver. It is used in the treatment of portal hypertension.

2 any of the natural communications between the branches of the hepatic portal vein in the liver and the inferior vena cava.
Top

Back  -    New Search

portal hypertension (por-t'l) n.

a state in which the pressure within the hepatic portal vein is increased, causing enlargement of the spleen and ascites. The commonest cause is cirrhosis. Treatment is by diuretic drugs, by surgery (see PORTACAVAL ANASTOMOSIS), or by implanting a stent within the liver to join portal tract veins to a hepatic vein tributary.

Back  -    New Search

portal system n.

a vein or group of veins that terminates at both ends in a capillary bed. hepatic p. s. the best known portal system, consisting of the portal vein and its tributaries.

Back  -    New Search

portal vein n.

a vein that conveys blood from the stomach, intestines, spleen, and pancreas to the liver.

Back  -    New Search

port-wine stain (port-wyn) n.

see NAEVUS.

Back  -    New Search

POS n.

see POLYCYSTIC OVARY SYNDROME.

Back  -    New Search

position (p-zish-n) n.

a posture or attitude assumed by a patient in order to facilitate nursing, diagnostic, or surgical procedures (see illustration).

Back  -    New Search

positive pressure ventilation (poz-it-iv) n.

the forcible passage of air into the lungs to stimulate breathing movements. See also RESPIRATOR.

Back  -    New Search

positron (poz-i-tron) n.

an electrically charged particle, released in some radioactive decays, that has the same mass as an electron but opposite charge. It has a very short lifetime as it quickly reacts with an electron to produce gamma rays.

Back  -    New Search

positron emission tomography (PET) n.

a technique of nuclear medicine used to evaluate the activity of tissues of the brain, chest, and abdomen by measuring their uptake of injected 2-deoxyglucose labelled with radioactive fluorine. As this is metabolized, it emits positrons, which are annihilated with the production of gamma rays, detected by means of a tomographic gamma camera.

Back  -    New Search

posology (p-sol-ji) n.

the science of the dosage of medicines.

Back  -    New Search

posseting (poss-it-ing) n.

the regurgitation of a small amount of milk, usually with some wind, by a baby after feeding.

Back  -    New Search

Possum (poss-m) n.

a device that enables severely paralysed patients to use typewriters, telephones, and other machines. Modern Possums are operated by micro-switches that require only the slightest movement in any limb. The name derives from Patient-Operated Selector Mechanism (POSM).

Back  -    New Search

post- prefix

denoting 1 following; after.

2 (in anatomy) behind.
Top

Back  -    New Search

postcibal (pohst-sy-bl) adj.

occurring after eating.

Back  -    New Search

postcoital (pohst-koh-i-t'l) adj.

occurring after sexual intercourse. p. contraception prevention of pregnancy after intercourse has taken place. This can be achieved by spaced oral doses of oestrogen and progestogen, a single oral dose of the anti-progesterone drug mifepristone, or the insertion of an IUCD. p. test a test used in the investigation of infertility. A specimen of cervical mucus, taken 6–24 hours after coitus in the postovulatory phase of the menstrual cycle, is examined under a microscope for the presence of motile spermatozoa.

Back  -    New Search

postconcussional syndrome (pohst-kn-kush-n-l) n.

persistent headaches, giddiness, and lack of concentration that may follow a head injury.

Back  -    New Search

postepileptic (pohst-epi-lep-tik) adj.

occurring after an epileptic fit.

Back  -    New Search

posterior (poss-teer-i-er) adj.

situated at or near the back of the body or an organ. p. chamber the rear section of the eye, behind the lens, which is filled with vitreous humour.

Back  -    New Search

postero- prefix

denoting posterior.

Back  -    New Search

postganglionic (pohst-gang-li-on-ik) adj.

describing a neurone in a nerve pathway that starts at a ganglion and ends at the muscle or gland that it supplies. Compare PREGANGLIONIC.

Back  -    New Search

postgastrectomy syndrome (pohst-gas-trek-tmi) n.

see DUMPING SYNDROME.

Back  -    New Search

posthitis (poss-th'y-tis) n.

inflammation of the foreskin. This usually occurs in association with balanitis (see BALANOPOSTHITIS).

Back  -    New Search

posthumous birth (poss-tew-ms) n.

1 delivery of a child by Caesarean section after the mother's death.

2 birth of a child after the father's death.
Top

Back  -    New Search

postmature (pohst-m-tewr) adj.

describing a baby born after 42 weeks of gestation (calculated from the first day of the last menstrual period).
—postmaturity n.

Back  -    New Search

postmenopause (pohst-men--pawz) n.

the period of a woman's life after the menopause.

Back  -    New Search

post mortem (pohst mor-tm)

Latin: after death. See AUTOPSY.

Back  -    New Search

postnatal (pohst-nay-t'l) adj.

following childbirth. p. depression sadness affecting a woman after childbirth. It ranges from a fleeting misery (so-called baby blues ) that affects about half of all women after childbirth, especially after the birth of their first baby, to a pathological condition: see PUERPERAL (DEPRESSION).

Back  -    New Search

postoperative (pohst-op-er--tiv) adj.

following operation: referring to the condition of a patient or to the treatment given at this time.

Back  -    New Search

postpartum (pohst-par-tm) adj.

relating to the period of a few days immediately after birth.

Back  -    New Search

postprandial (pohst-pran-di-l) adj.

occurring after eating.

Back  -    New Search

Post-Registration Education and Practice Project (pohst-rej-i-stray-shn) n.

see PREPP.

Back  -    New Search

post-traumatic stress disorder (PTSD) (pohst-traw-mat-ik) n.

an anxiety disorder caused by the major personal stress of a serious or frightening event, such as exposure to warfare or a disaster involving many casualties. The sufferer experiences the persistent recurrence of images or memories of the event, together with nightmares, insomnia, a sense of isolation, guilt, irritability, and loss of concentration.

Back  -    New Search

postviral fatigue syndrome (pohst-vy-rl) n.

see CHRONIC FATIGUE SYNDROME.

Back  -    New Search

potassium (p-tas-im) n.

a mineral element and an important constituent of the human body. It is the main base ion of intracellular fluid. High concentrations occur particularly in kidney failure and may lead to arrhythmia and finally to cardiac arrest. Low values result from fluid loss, e.g. due to vomiting or diarrhoea, and this may lead to general muscle paralysis. Symbol: K.

Back  -    New Search

potassium chloride n.

a salt of potassium administered by mouth or injection to prevent and treat potassium deficiency, especially during treatment with certain diuretics. Trade names: Nu-K , Slow-K .

Back  -    New Search

potassium hydroxyquinoline (hy-droks-i-kwin--leen) n.

a salt of potassium that has antifungal, antibacterial, and deodorant activities.

Back  -    New Search

potassium permanganate (per-mang--nayt) n.

a salt of potassium used for disinfecting and cleansing wounds and as a general skin antiseptic. It irritates mucous membranes and is poisonous if taken into the body.

Back  -    New Search

Potter syndrome (pot-er) n.

a congenital condition characterized by absence of kidneys, resulting in decreased amniotic fluid (see OLIGOHYDRAMNIOS) and compression of the fetus. Affected babies have poorly developed lungs, a characteristic wrinkled and flattened facial appearance, and leg deformities and do not usually survive. [E. L. Potter (1901– ), US pathologist]

Back  -    New Search

Pott's disease (pots) n.

tuberculosis of the backbone. Untreated, it can lead to a hunchback deformity. [P. Pott (1714–88), British surgeon]

Back  -    New Search

Pott's fracture n.

see FRACTURE.

Back  -    New Search

pouch (powch) n.

1 (in anatomy) a small sac-like structure, especially occurring as an outgrowth of a larger structure. p. of Douglas a pouch of peritoneum occupying the space between the rectum and uterus. [J. Douglas (1675–1742), British anatomist]

2 (in surgery) a sac created from a loop of intestine and used to replace a section of rectum that has been surgically removed, for example for ulcerative colitis. See also ILEAL POUCH.
Top

Back  -    New Search

poultice (fomentation) (pohl-tis) n.

a preparation of hot moist material applied to any part of the body to increase local circulation, alleviate pain, or soften the skin.

Back  -    New Search

Poupart's ligament (poo-parz) n.

see INGUINAL (LIGAMENT). [F. Poupart (1661–1708), French anatomist]

Back  -    New Search

powder (pow-der) n.

(in pharmacy) a medicinal preparation consisting of a mixture of two or more drugs in the form of fine particles.

Back  -    New Search

pox (poks) n.

1 an infectious disease causing a skin rash.

2 a rash of pimples that become pus-filled, as in chickenpox and smallpox.
Top

Back  -    New Search

poxvirus (poks-vy-rs) n.

one of a group of large DNA-containing viruses including those that cause smallpox (variola) and cowpox (vaccinia).

Back  -    New Search

PPLO pl. n.

see MYCOPLASMA.

Back  -    New Search

practice nurse (prak-tis) n.

a trained nurse caring for the patients of one or more general practitioners in the consulting room and on domiciliary consultations. In Britain practice nurses are usually employed by GPs but may also be employed by community trusts as district nurses.

Back  -    New Search

Prader-Willi syndrome (prah-der vil-i) n.

a congenital condition in which obesity is associated with mental retardation and small genitalia; diabetes mellitus frequently develops in affected individuals. [A. Prader and H. Willi (20th century), Swiss paediatricians]

Back  -    New Search

pravastatin (pr-vas-t-tin) n.

a drug used to reduce abnormally high levels of cholesterol in the blood. Trade name: Lipostat .

Back  -    New Search

praziquantel (praz-i-kwon-tel) n.

an anthelmintic drug used to eliminate tapeworms, schistosomes, liver flukes, and lung flukes. It is administered by mouth. Trade name: Biltricide .

Back  -    New Search

prazosin (praz-oh-sin) n.

a drug used in the treatment of high blood pressure (hypertension) by reducing peripheral vascular resistance (see ALPHA BLOCKER). It is administered by mouth. Trade name: Hypovase .

Back  -    New Search

pre- prefix

denoting 1 before; preceding.

2 (in anatomy) in front of; anterior to.
Top

Back  -    New Search

precancerous (pree-kan-ser-s) adj.

describing a nonmalignant condition that is known to become malignant if left untreated.

Back  -    New Search

precipitin (pri-sip-it-in) n.

any antibody that combines with its antigen to form a complex that is seen as a precipitate. The precipitin reaction is a useful means of confirming the identity of an unknown antigen or establishing that a serum contains antibodies to a known disease. See also AGGLUTINATION.

Back  -    New Search

precocious puberty n.

the development in girls of breasts or pubic hair before the age of six or menstruation before the age of eight, and in boys the development of pubic hair or other adult sexual features below the age of nine. In girls 90% of cases have no underlying abnormalities, but in boys approximately half have a serious underlying cause, of which malignant testicular or adrenal tumours are the most common.

Back  -    New Search

precocity (pri-kos-iti) n.

an acceleration of normal development. The intellectually precocious child has a high IQ and may become isolated from his contemporaries or frustrated at school.
—precocious (pri-koh-shs) adj.

Back  -    New Search

precordium (pree-kor-dim) n.

the region of the thorax immediately over the heart.
—precordial adj.

Back  -    New Search

precursor (pri-ker-ser) n.

a substance from which another, usually more biologically active, substance is formed. For example, trypsinogen is the precursor of the enzyme trypsin.

Back  -    New Search

predigestion (pree-dy-jes-chn) n.

the partial digestion of foods by artificial means before they are taken into the body.

Back  -    New Search

predisposition (pree-dis-p-zish-n) n.

a tendency to be affected by a particular disease or kind of disease. See also DIATHESIS.

Back  -    New Search

prednisolone (pred-nis--lohn) n.

a synthetic corticosteroid used to treat rheumatic diseases and inflammatory and allergic conditions. It is administered by mouth, injected into joints, or applied in creams, lotions, and ointments. Trade names: Deltacortril , Deltastab , Precortisyl , Prednesol .

Back  -    New Search

prednisone (pred-ni-sohn) n.

a synthetic corticosteroid administered by mouth to treat rheumatic diseases, severe allergic conditions, inflammatory conditions, and leukaemia. Trade name: Decortisyl .

Back  -    New Search

pre-eclampsia (pregnancy-induced hypertension, PIH) (pree-i-klamp-si) n.

high blood pressure (greater than 140/90 mmHg) developing during pregnancy in a woman whose blood pressure was previously normal. It is often accompanied by excessive fluid retention and less often by the the presence of protein in the urine. See also ECLAMPSIA.

Back  -    New Search

prefrontal leucotomy (pree-frun-t'l) n.

see LEUCOTOMY.

Back  -    New Search

prefrontal lobe n.

the region of the brain at the very front of each cerebral hemisphere. The functions of the lobe are concerned with emotions, memory, learning, and social behaviour.

Back  -    New Search

preganglionic (pree-gang-li-on-ik) adj.

describing fibres in a nerve pathway that end in a ganglion, where they form synapses with postganglionic fibres.

Back  -    New Search

pre-gangrene (pree-gang-reen) n.

the penultimate stage of vascular insufficiency before gangrene sets in; the term is usually applied to ischaemia of the lower limb.

Back  -    New Search

pregnancy (preg-nn-si) n.

the period during which a woman carries a developing fetus, normally in the uterus (compare ECTOPIC PREGNANCY). Pregnancy lasts for approximately 266 days, from conception until the baby is born, or 280 days from the first day of the last menstrual period (see NAEGELE RULE). See also PSEUDOCYESIS (PHANTOM PREGNANCY). p. test any of several methods used to demonstrate whether or not a woman is pregnant. Most pregnancy tests are based on the detection, by immunological methods, of a hormone, human chorionic gonadotrophin, in the urine or in the serum.
—pregnant adj.

Back  -    New Search

pregnancy-induced hypertension (PIH) n.

see PRE-ECLAMPSIA.

Back  -    New Search

pregnanediol (preg-nayn-dy-ol) n.

a steroid that is formed during the metabolism of the female sex hormone progesterone. It occurs in the urine during pregnancy and certain phases of the menstrual cycle.

Back  -    New Search

pregnenolone (preg-neen--lohn) n.

a steroid synthesized in the adrenal glands, ovaries, and testes. Pregnenolone is an important intermediate product in steroid hormone synthesis.

Back  -    New Search

preimplantation diagnosis (pree-im-plahn-tay-shn) n.

prenatal genetic diagnosis extended to the earliest stages of embryonic development, before implantation occurs.

Back  -    New Search

premature beat (prem--tewr) n.

see ECTOPIC BEAT.

Back  -    New Search

premature birth n.

birth of a baby weighing less than 2.5 kg (5½ lb). Usually this is indicative of preterm birth but it can also be caused by intrauterine growth retardation (IUGR).

Back  -    New Search

premedication (pree-med-i-kay-shn) n.

drugs administered to a patient before an operation. Premedication usually comprises injection of a sedative together with a drug, such as atropine, to dry up the secretions of the lungs (which might otherwise be inhaled during anaesthesia).

Back  -    New Search

premenstrual tension (pree-men-stroo-l) n.

a condition of nervousness, irritability, emotional disturbance, headache, and/or depression affecting some women for up to 10 days before menstruation.

Back  -    New Search

premolar (pree-moh-ler) n.

either of the two teeth on each side of each jaw behind the canines and in front of the molars in the adult dentition.

Back  -    New Search

prenatal diagnosis (antenatal diagnosis) (pree-nay-t'l) n.

diagnostic procedures carried out on pregnant women in order to discover genetic or other abnormalities in the developing fetus. Ultrasound scanning (see ULTRASONOGRAPHY) remains the cornerstone of prenatal diagnosis. Other tests include estimation of the level of alpha-fetoprotein in the mother's serum and the amniotic fluid; chromosome and enzyme analysis of fetal cells obtained by amniocentesis or, at an earlier stage of pregnancy, by chorionic villus sampling; and examination of fetal blood obtained by fetoscopy or cordocentesis. See also PREIMPLANTATION DIAGNOSIS.

Back  -    New Search

preoperative (pree-op-er--tiv) adj.

before operation: referring to the condition of a patient or to treatment, such as sedation, given at this time.

Back  -    New Search

prepatellar bursitis (pree-p-tel-er) n.

see HOUSEMAID'S KNEE.

Back  -    New Search

PREPP n.

(in the UK) Post-Registration Education and Practice Project: a project, launched by the UKCC, that aims to establish standards of practice and principles of education beyond registration to provide for competent and cost-effective nursing, midwifery, and health visiting.

Back  -    New Search

prepubertal (pree-pew-ber-t'l) adj.

relating to or occurring in the period before puberty.

Back  -    New Search

prepuce (foreskin) (pree-pewss) n.

the fold of skin that grows over the glans penis. On its inner surface modified sebaceous glands (preputial glands ) secrete a lubricating fluid over the glans.
—preputial (pree-pew-shl) adj.

Back  -    New Search

presby- (presbyo-) prefix

denoting old age.

Back  -    New Search

presbyacusis (prezbi--kew-sis) n.

the progressive sensorineural deafness that occurs with age.

Back  -    New Search

presbyopia (prezbi-oh-pi) n.

difficulty in reading at the usual distance and in performing other close work, due to the decline with age in the ability of the eye to focus on close objects.

Back  -    New Search

prescribed disease (pri-skrybd) n.

one of a number of illnesses (currently 48) arising as a result of employment requiring close contact with a hazardous substance or circumstance. Examples include decompression sickness in divers and infections such as anthrax in those handling wool.

Back  -    New Search

prescription (pri-skrip-shn) n.

a written direction from a registered medical practitioner to a pharmacist for preparing and dispensing a drug.

Back  -    New Search

presenility (pree-sin-il-iti) n.

premature ageing of the mind and body, so that a person shows the reduction in mental and physical abilities normally found only in old age. See also DEMENTIA, PROGERIA.
—presenile (pree-see-nyl) adj.

Back  -    New Search

present (pri-zent) vb.

1 (of a patient) to come forward for examination and treatment because of experiencing specific symptoms (presenting symptoms ).

2 (in obstetrics) see PRESENTATION.
Top

Back  -    New Search

presentation (prez-n-tay-shn) n.

the part of the fetus that is closest to the birth canal and can be felt on inserting the finger into the vagina. Normally the head presents (cephalic p. ). However, the buttocks may present (see BREECH PRESENTATION), or, if the fetus lies transversely across the uterus, the shoulder or arm may present.

Back  -    New Search

pressor (pres-er) n.

an agent that raises blood pressure. See VASOCONSTRICTOR.

Back  -    New Search

pressure area (presh-er) n.

any of the areas of the body where a bone is close to the skin surface, so that pressure on that area (e.g. by lying in bed) deprives the overlying tissues of their blood supply (see BEDSORE).

Back  -    New Search

pressure index (PI) (in-deks) n.

the ratio of the pressure in the posterior tibial artery to that in the brachial artery, which reflects the degree of arterial obstruction in the artery of the lower limb.

Back  -    New Search

pressure point n.

a point at which an artery lies over a bone on which it may be compressed by finger pressure, to arrest haemorrhage beyond.

Back  -    New Search

pressure sore n.

see BEDSORE.

Back  -    New Search

presystole (pree-sis-t-li) n.

the period in the cardiac cycle just preceding systole.

Back  -    New Search

preterm birth (pree-term) n.

birth of a baby before 37 weeks (259 days) of gestation (calculated from the first day of the mother's last menstrual period); a birth at less than 23 weeks is at present incompatible with life. Conditions affecting preterm babies may include respiratory distress syndrome, feeding difficulties, inability to maintain normal body temperature, apnoea, infection, necrotizing enterocolitis, and brain haemorrhages. Supportive treatment is provided in an incubator in a neonatal unit.

Back  -    New Search

preventive medicine (pri-ven-tiv) n.

the branch of medicine whose main aim is the prevention of disease.

Back  -    New Search

Priadel (pry--del) n.

see LITHIUM.

Back  -    New Search

priapism (pry--pizm) n.

persistent painful erection of the penis that requires decompression. The condition may result from the administration of papaverine or a similar drug or it may occur in patients with sickle-cell trait or those on haemodialysis.

Back  -    New Search

prickle cells (prik-l) pl. n.

cells with cytoplasmic processes that form intercellular bridges. The germinative layer of the epidermis is sometimes called the prickle cell layer .

Back  -    New Search

prickly heat (prik-li) n.

an itchy rash of small raised red spots. It occurs usually on the face, neck, back, chest, and thighs in hot moist weather. The only treatment is removal of the patient to a cool (air-conditioned) place. Medical name: miliaria .

Back  -    New Search

prilocaine (pril-oh-kayn) n.

a local anaesthetic used particularly in ear, nose, and throat surgery and in dentistry. It is applied in a solution to mucous membranes or injected. Trade name: Citanest .

Back  -    New Search

primaquine (pry-m-kween) n.

a drug used to treat malaria. It is administered by mouth, usually in combination with other antimalarial drugs, such as chloroquine.

Back  -    New Search

primary health care (pry-mer-i) n.

comprehensive health care for individuals and families in the community provided through an integrated network of services covering the treatment of common illness and injuries, maternal and child health problems, the care and rehabilitation of people with long- and short-term handicaps and disabilities, and health education. In the UK the delivery of primary health care is based on general practitioner services. It works best where there is a multidisciplinary team approach to care. Compare SECONDARY HEALTH CARE, TERTIARY HEALTH CARE.

Back  -    New Search

primary nursing n.

a method of organizing nursing care in which one nurse (the primary nurse ) is responsible for assessing the patient, planning his care, and evaluating his progress throughout his stay in hospital and on discharge.

Back  -    New Search

primary teeth pl. n.

see DENTITION.

Back  -    New Search

prime (prym) vb.

(in chemotherapy) to administer small doses of a cytotoxic drug to a patient prior to high-dose chemotherapy and/or radiotherapy. This causes proliferation of the primitive bone marrow cells and aids subsequent regeneration of the bone marrow.

Back  -    New Search

prime mover n.

see AGONIST.

Back  -    New Search

primidone (pry-mid-ohn) n.

an anticonvulsant drug administered by mouth to treat major epilepsy. Trade name: Mysoline .

Back  -    New Search

primigravida (pry-mi-grav-id-) n.

a woman experiencing her first pregnancy.

Back  -    New Search

primipara (pry-mip-er-) n.

a woman who has given birth to one infant capable of survival.

Back  -    New Search

primordial (pry-mor-di-l) adj.

(in embryology) describing cells or tissues that are formed in the early stages of embryonic development.

Back  -    New Search

P-R interval n.

the interval on an electrocardiogram between the onset of atrial activity and ventricular activity.

Back  -    New Search

prion (pree-on) n.

an abnormal form of a constituent protein of brain cells that accumulates in and destroys brain tissue. It is very stable and resistant and is thought to interact with normal prion protein in such a way as to convert it to abnormal prion. Prions are now widely accepted as being the causal agents of Creutzfeldt-Jakob disease and other spongiform encephalopathies.

Back  -    New Search

pro- prefix

denoting 1 before; preceding.

2 a precursor.
Top

3 in front of.
Top

Back  -    New Search

probang (proh-bang) n.

a long flexible rod with a small sponge, ball, or tuft at the end, used to remove obstructions from the larynx or oesophagus.

Back  -    New Search

probe (prohb) n.

a thin rod of pliable metal with a blunt swollen end. The instrument is used for exploring cavities, wounds, fistulae, or sinus channels. See also HEATER-PROBE.

Back  -    New Search

probenecid (proh-ben--sid) n.

a drug that reduces the level of uric acid in the blood (see URICOSURIC DRUG), administered by mouth in the treatment of gout. Trade name: Benemid .

Back  -    New Search

problem-solving approach n.

a method of planning work involving assessment, problem identification, planning, implementation, and evaluation. See NURSING PROCESS.

Back  -    New Search

probucol (proh-bew-kol) n.

a drug used to lower cholesterol levels in the blood in patients with primary hypercholesterolaemia. It acts by increasing the breakdown of low-density lipoproteins and inhibits cholesterol synthesis. It is administered by mouth. Trade name: Lurselle .

Back  -    New Search

procainamide (proh-kayn--myd) n.

a drug that slows down the activity of the heart and is administered by mouth or injection to control abnormal heart rhythm. Trade name: Pronestyl .

Back  -    New Search

procaine (procaine hydrochloride) (proh-kayn) n.

a local anaesthetic administered by injection for spinal anaesthesia. It was formerly used in dentistry. Trade name: Novutex .

Back  -    New Search

procaine penicillin G n.

an antibiotic, consisting of penicillin and procaine, used to treat infections caused by organisms sensitive to penicillin. It is injected into muscle so that the penicillin is released slowly. Trade names: Bicillin , Triplopen .

Back  -    New Search

procarbazine (proh-kar-b-zeen) n.

a drug that inhibits growth of cancer cells by preventing cell division and is administered by mouth to treat such cancers as Hodgkin's disease. Trade name: Natulan .

Back  -    New Search

process (proh-ses) n.

(in anatomy) a thin prominence or protuberance.

Back  -    New Search

prochlorperazine (proh-klor-per--zeen) n.

a phenothiazine antipsychotic drug used to treat schizophrenia and other mental disorders, migraine, vertigo, nausea, and vomiting. It is administered by mouth, injection, or in suppositories. Trade name: Stemetil .

Back  -    New Search

procidentia (pros-i-den-shi) n.

the complete prolapse of an organ, especially the uterus, which protrudes from the vaginal opening.

Back  -    New Search

proct- (procto-) prefix

denoting the anus and/or rectum.

Back  -    New Search

proctalgia (proctodynia) (prok-tal-ji) n.

pain in the rectum or anus. p. fugax severe pain that suddenly affects the rectum and may last for minutes or hours. There is no structural disease and the pain is probably due to muscle spasm.

Back  -    New Search

proctatresia (prok-t-tree-zi) n.

see IMPERFORATE (ANUS).

Back  -    New Search

proctectasia (prok-tek-tay-zi) n.

enlargement or widening of the rectum, usually due to long-standing constipation.

Back  -    New Search

proctectomy (prok-tek-tmi) n.

surgical removal of the rectum. It is usually performed for cancer of the rectum and may require the construction of a permanent opening in the colon (see COLOSTOMY).

Back  -    New Search

proctitis (prok-ty-tis) n.

inflammation of the rectum. Symptoms are tenesmus, diarrhoea, and often bleeding. Proctitis is invariably present in ulcerative colitis and sometimes in Crohn's disease, but may occur independently (idiopathic p. ).

Back  -    New Search

proctocele (rectocele) (prok-toh-seel) n.

bulging or pouching of the rectum, usually a forward protrusion of the rectum into the posterior wall of the vagina in association with prolapse of the uterus.

Back  -    New Search

proctoclysis (prok-tok-li-sis) n.

an infusion of fluid into the rectum: formerly used to replace fluid but rarely employed now.

Back  -    New Search

proctocolectomy (prok-toh-k-lek-tmi) n.

a surgical operation in which the rectum and colon are removed. Removal of the whole rectum and colon (panproctocolectomy ) requires either a permanent opening of the ileum (see ILEOSTOMY) or the construction of an ileal pouch.

Back  -    New Search

proctocolitis (prok-toh-k-ly-tis) n.

inflammation of the rectum and colon, usually due to ulcerative colitis. See also PROCTITIS.

Back  -    New Search

proctodynia (prok-toh-din-i) n.

see PROCTALGIA.

Back  -    New Search

proctogram (prok-t-gram) n.

an X-ray photograph of the rectum taken after the introduction into it of a contrast medium. defecating p. a proctogram that demonstrates problems of abnormal defecation.

Back  -    New Search

proctology (prok-tol-ji) n.

the study of disorders of the rectum and anus.

Back  -    New Search

proctorrhaphy (prokt-o-rfi) n.

a surgical operation to stitch tears of the rectum or anus.

Back  -    New Search

proctoscope (prok-t-skohp) n.

an illuminated instrument through which the lower part of the rectum and the anus may be inspected.
—proctoscopy n.

Back  -    New Search

proctosigmoiditis (prok-toh-sig-moid-I-tis) n.

inflammation of the rectum and the sigmoid colon. See also PROCTOCOLITIS.

Back  -    New Search

proctotomy (prok-tot-mi) n.

incision into the rectum or anus to relieve stricture of these canals or to open an imperforate anus.

Back  -    New Search

procyclidine (proh-sy-kli-deen) n.

a drug, similar in its effects to atropine, administered by mouth or injection to reduce muscle tremor and rigidity in parkinsonism. Trade names: Arpicolin , Kemadrin .

Back  -    New Search

prodromal (proh-droh-ml) adj.

relating to the period of time between the appearance of the first symptoms of an infectious disease and the development of a rash or fever. p. rash a rash that precedes the full rash of an infectious disease.

Back  -    New Search

prodrome (proh-drohm) n.

a symptom indicating the onset of a disease.

Back  -    New Search

proenzyme (zymogen) (proh-en-zym) n.

the inactive form in which certain enzymes (e.g. digestive enzymes) are originally produced and secreted.

Back  -    New Search

proflavine (proh-flay-vin) n.

a dye used as an antiseptic in the form of skin applications and eye drops.

Back  -    New Search

profunda (proh-fun-d) adj.

describing blood vessels that are deeply embedded in the tissues they supply.

Back  -    New Search

profundaplasty (proh-fun-d-plasti) n.

surgical enlargement of the junction of the femoral artery and its deep branch, a common operation to relieve narrowing by atherosclerosis at this point.

Back  -    New Search

progeria (proh-jeer-i) n.

a very rare condition in which all the signs of old age appear and progress in a child, so that ‘senility’ is reached before puberty.

Back  -    New Search

progesterone (proh-jest-er-ohn) n.

a steroid hormone secreted by the corpus luteum of the ovary, the placenta, and also (in small amounts) by the adrenal cortex and testes. It is responsible for preparing the endometrium of the uterus for pregnancy.

Back  -    New Search

progestogen (proh-jest-oh-jn) n.

one of a group of naturally occurring or synthetic steroid hormones, including progesterone, that maintain the normal course of pregnancy. Progestogens are used to treat premenstrual tension, amenorrhoea, and abnormal bleeding from the uterus. Because they prevent ovulation, progestogens are a major constituent of oral contraceptives and other forms of hormonal contraception.

Back  -    New Search

proglottis (proh-glot-iss) n. (pl. proglottids or proglottides)

one of the segments of a tapeworm. Mature segments, situated at the posterior end of the worm, each consist mainly of a branched uterus packed with eggs.

Back  -    New Search

prognathism (prog-n-thizm) n.

the state of one jaw being markedly larger than the other and therefore in front of it.
—prognathic (prog-nath-ik) adj.

Back  -    New Search

prognosis (prog-noh-sis) n.

an assessment of the future course and outcome of a patient's disease.

Back  -    New Search

progressive (pr-gres-iv) adj.

(of a disease) increasing in severity or extent; expected to get worse.

Back  -    New Search

progressive supranuclear palsy n.

a progressive neurological disorder resulting from degeneration of the motor neurones, basal ganglia, and brainstem. Starting in late middle age, it is characterized by a staring facial expression due to impaired ability to move the eyes up and down, progressing to difficulties in swallowing, speech, balance, and movement and general spasticity.

Back  -    New Search

proguanil (proh-gwan-il) n.

a drug that kills malaria parasites and is administered by mouth in the prevention and treatment of malaria. Trade name: Paludrine .

Back  -    New Search

proinsulin (proh-ins-yoo-lin) n.

a substance produced in the pancreas from which the hormone insulin is derived.

Back  -    New Search

Project 2000 (proj-ekt) n.

a scheme for nurse education introduced by the UKCC in 1989. Student nurses gain a diploma in higher education as well as their registered nurse qualification.

Back  -    New Search

projection (pr-jek-shn) n.

(in psychology) the attribution of one's own qualities to other people. This is one of the defence mechanisms; people who cannot tolerate their own feelings may cope by imagining that other people have those feelings.

Back  -    New Search

prolactin (lactogenic hormone, luteotrophic hormone, luteotrophin) (proh-lak-tin) n.

a hormone, synthesized and stored in the anterior pituitary gland, that stimulates milk production after childbirth and also stimulates production of progesterone by the corpus luteum in the ovary.

Back  -    New Search

prolapse (proh-laps) n.

downward displacement of an organ or tissue from its normal position. p. of the rectum descent of the rectum to lie outside the anus. p. of the uterus descent of the cervix, or the whole of the uterus, into the vagina. The cervix may be visible at the vaginal opening or the uterus may be completely outside the vagina. It is often caused by stretching and tearing of the supporting tissues during childbirth.

Back  -    New Search

prolapsed intervertebral disc (PID) n.

a ‘slipped disc’: protrusion of the pulpy inner material of an intervertebral disc through the fibrous outer coat, causing pressure on adjoining nerve roots, ligaments, etc. Treatment is by rest, traction, and analgesics; if these fail, surgery may be necessary (see LAMINECTOMY, MICRODISCECTOMY).

Back  -    New Search

proliferate (pr-lif-er-ayt) vb.

to grow rapidly by cell division: applied particularly to malignant tumours.
—proliferation n.

Back  -    New Search

proline (proh-leen) n.

an amino acid found in many proteins.

Back  -    New Search

promazine (proh-m-zeen) n.

a phenothiazine antipsychotic drug administered by mouth or injection to relieve agitation, confusion, severe pain, anxiety, nausea, and vomiting and in the treatment of alcoholism and drug withdrawal symptoms. Trade name: Sparine .

Back  -    New Search

promethazine (proh-meth--zeen) n.

a powerful antihistamine drug administered by mouth or injection to treat allergic conditions and insomnia. It is also used as an antitussive in cough mixtures. Trade names: Avomine , Phenergan .

Back  -    New Search

promontory (prom-n-ter-i) n.

(in anatomy) a projecting part of an organ or other structure.

Back  -    New Search

pronation (proh-nay-shn) n.

the act of turning the hand so that the palm faces downwards. In this position the radius and ulna are crossed. Compare SUPINATION.

Back  -    New Search

pronator (proh-nay-ter) n.

any muscle that causes pronation of the forearm and hand.

Back  -    New Search

prone (prohn) adj.

1 lying with the face downwards.

2 (of the forearm) in the position in which the palm of the hand faces downwards. Compare SUPINE.
Top

Back  -    New Search

propantheline (proh-panth--leen) n.

a drug that decreases activity of smooth muscle (see PARASYMPATHOLYTIC) and is administered by mouth or injection to treat disorders of the digestive system, including stomach and duodenal ulcers, and enuresis (bed wetting). Trade name: Pro-Banthine .

Back  -    New Search

properdin (proh-per-din) n.

a group of substances in blood plasma that, in combination with complement and magnesium ions, is capable of destroying certain bacteria and viruses.

Back  -    New Search

prophase (proh-fayz) n.

the first stage of mitosis and of each division of meiosis, in which the chromosomes become visible under the microscope.

Back  -    New Search

prophylactic (pro-fil-ak-tik) n.

an agent that prevents the development of a condition or disease.

Back  -    New Search

prophylaxis (pro-fil-aks-iss) n.

any means taken to prevent disease, such as immunization.
—prophylactic adj.

Back  -    New Search

propranolol (proh-pran--lol) n.

a drug (see BETA BLOCKER) administered by mouth or injection to treat abnormal heart rhythm, angina, and high blood pressure and to relieve anxiety. Trade name: Inderal .

Back  -    New Search

proprietary name (pr-pry-t-er-i) n.

(in pharmacy) the trade name of a drug: the name assigned to it by the firm that manufactured it.

Back  -    New Search

proprioceptor (proh-pri--sep-ter) n.

a specialized sensory nerve ending (see RECEPTOR) that monitors internal changes in the body brought about by movement and muscular activity. Proprioceptors in muscles and tendons assist in coordinating muscular activity.

Back  -    New Search

proptosis (prop-toh-sis) n.

forward displacement of an organ, especially the eye (see EXOPHTHALMOS).

Back  -    New Search

propylthiouracil (proh-pil-th'y-oh-yoor--sil) n.

a drug that reduces thyroid activity and is administered by mouth to treat thyrotoxicosis and to prepare patients for surgical removal of the thyroid gland.

Back  -    New Search

Proscar (pros-kar) n.

see FINASTERIDE.

Back  -    New Search

prosop- (prosopo-) prefix

denoting the face.

Back  -    New Search

prostaglandin (pros-t-gland-in) n.

one of a group of hormone-like substances present in a wide variety of tissues and body fluids. Prostaglandins have many actions; for example, they cause contraction of smooth muscle (including that of the uterus) and dilatation of blood vessels, they are mediators in the process of inflammation, and they are involved in the production of mucus in the stomach. Synthetic prostaglandins are used to induce labour or produce abortion, to treat peptic ulcers, and in the treatment of newborn babies with congenital heart disease.

Back  -    New Search

prostate cancer (pros-tayt) n.

a malignant tumour (carcinoma) of the prostate gland, a common form of cancer in elderly men. It may progress slowly over many years and give symptoms similar to those of benign enlargement of the prostate (see PROSTATE GLAND).

Back  -    New Search

prostatectomy (pros-t-tek-tmi) n.

surgical removal of the prostate gland. The operation is necessary to relieve retention of urine or impaired urinary flow due to enlargement of the prostate. It can be performed through the bladder (transvesical p. ), through the surrounding capsule of the prostate (retropubic p. ), or through the urethra (transurethral p. ). See also RESECTION.

Back  -    New Search

prostate gland n.

a male accessory sex gland that opens into the urethra just below the bladder and vas deferens. During ejaculation it secretes an alkaline fluid that forms part of the semen. The prostate may become enlarged in elderly men (benign prostatic hypertrophy, BPH ). This obstructs the neck of the bladder and is treated by surgery (see PROSTATECTOMY, RESECTION) or by means of drugs.

Back  -    New Search

prostatic specific antigen (PSA) (pros-tak-ik) n.

an enzyme produced by the glandular epithelium of the prostate. Increased quantities are secreted when the gland enlarges and levels of PSA in the blood are significantly elevated in cancer of the prostate.

Back  -    New Search

prostatitis (pros-t-ty-tis) n.

inflammation of the prostate gland. This may be due to bacterial infection and can be either acute or chronic.

Back  -    New Search

prostatocystitis (pros-t-toh-sis-ty-tis) n.

inflammation of the prostate gland associated with inflammation of the urinary bladder.

Back  -    New Search

prostatorrhoea (pros-t-t-ree-) n.

an abnormal discharge of thin watery fluid from the prostate gland. This occurs in some patients with acute prostatitis.

Back  -    New Search

prosthesis (pros-th'ee-sis) n. (pl. prostheses)

any artificial device that is attached to the body as a substitute for a missing or nonfunctional part. Prostheses include artificial limbs, hearing aids and cochlear implants, dentures, and implanted pacemakers. See also IMPLANT. penile p. a malleable, semirigid, or inflatable rod inserted into the corpora cavernosa of the penis to produce rigidity sufficient for vaginal penetration in men with impotence.
—prosthetic (pros-thet-ik) adj.

Back  -    New Search

prosthetic dentistry (prosthodontics) n.

the branch of dentistry concerned with the provision of dentures, bridges, and implant-retained prostheses.

Back  -    New Search

prosthodontics (pros-thoh-don-tiks) n.

see PROSTHETIC DENTISTRY.

Back  -    New Search

prostration (pros-tray-shn) n.

extreme exhaustion.

Back  -    New Search

protamine (proh-t-meen) n.

one of a group of simple proteins that can be conjugated with nucleic acids to form nucleoproteins. p. zinc insulin a combination of protamine, insulin, and zinc that is absorbed much more slowly than ordinary insulin and thus reduces the frequency of injections.

Back  -    New Search

protanopia (proh-t-noh-pi) n.

see DALTONISM.

Back  -    New Search

protease (proh-ti-ayz) n.

any enzyme that catalyses the splitting of a protein. p. inhibitor one of a recently developed class of drugs that inhibit the action of protease produced by HIV: used in the treatment of AIDS.

Back  -    New Search

protein (proh-teen) n.

one of a group of organic compounds made up of one or more chains of amino acids. Proteins are essential constituents of the body; they form the structural material of muscles, tissues, organs, etc., and are equally important as regulators of function, as enzymes and hormones. Proteins are synthesized in the body from their constituent amino acids, which are obtained from the digestion of protein in the diet.

Back  -    New Search

proteinuria (proh-tin-yoor-i) n.

see ALBUMINURIA.

Back  -    New Search

proteolysis (proh-ti-ol-i-sis) n.

the process whereby protein molecules are broken down by proteolytic enzymes into their constituent amino acids, which are then absorbed into the bloodstream.
—proteolytic (proh-ti--lit-ik) adj.

Back  -    New Search

proteolytic enzyme n.

a digestive enzyme that causes the breakdown of protein.

Back  -    New Search

proteose (proh-ti-ohz) n.

a product of the hydrolytic decomposition of protein.

Back  -    New Search

Proteus (proh-ti-s) n.

a genus of rodlike Gram-negative flagellate highly motile bacteria common in the intestines and in decaying organic material. P. vulgaris a species that can cause urinary tract infections.

Back  -    New Search

prothrombin (proh-throm-bin) n.

a substance, present in blood plasma, that is the inactive precursor from which the enzyme thrombin is derived during the process of blood coagulation. See also COAGULATION FACTORS. p. time (PT) the time taken for blood clotting to occur in a sample of blood to which calcium and thromboplastin have been added; a prolonged PT indicates a deficiency of coagulation factors. Measurement of PT is used to control anticoagulant therapy (e.g. with warfarin).

Back  -    New Search

proto- prefix

denoting 1 first.

2 primitive; early.
Top

3 a precursor.
Top

Back  -    New Search

proton-pump inhibitor (proh-ton-pump) n.

a drug that reduces gastric acid secretion by blocking an enzyme (the proton pump ) within the oxyntic (parietal) cells of the gastric glands. Proton-pump inhibitors include omeprazole and lansoprazole; they are used for treating gastric and duodenal ulcers, reflux oesophagitis, and the hypersecretion caused by gastrinomas.

Back  -    New Search

protopathic (proh-t-path-ik) adj.

describing the ability to perceive only strong stimuli of pain, heat, etc. Compare EPICRITIC.

Back  -    New Search

protoplasm (proh-t-plazm) n.

the material of which living cells are made, which includes the cytoplasm and nucleus.
—protoplasmic adj.

Back  -    New Search

protoporphyrin IX (proh-toh-por-fi-rin) n.

the most common type of porphyrin found in nature. It is a constituent of haemoglobin, myohaemoglobin, and the commoner chlorophylls.

Back  -    New Search

protozoa (proh-t-zoh-) pl. n.

a group of microscopic single-celled organisms. Most protozoa are free-living but some, such as Plasmodium and Leishmania, are important disease-causing parasites of man. See also AMOEBA.
—protozoan adj., n.

Back  -    New Search

protriptyline (proh-trip-ti-leen) n.

a tricyclic antidepressant drug administered by mouth to treat moderate or severe depression, especially in apathetic and withdrawn patients. Trade name: Concordin .

Back  -    New Search

protuberance (pr-tew-ber-ns) n.

(in anatomy) a rounded projecting part.

Back  -    New Search

proud flesh (prowd) n.

a large amount of soft granulation tissue that may develop during the healing of a wound of large surface area.

Back  -    New Search

provitamin (proh-vit--min) n.

a substance that is not itself a vitamin but can be converted to a vitamin in the body. An example is ß-carotene, which can be converted into vitamin A.

Back  -    New Search

proximal (proks-i-ml) adj.

(in anatomy) situated close to the origin or point of attachment or close to the median line of the body. Compare DISTAL.

Back  -    New Search

Prozac (proh-zak) n.

see FLUOXETINE.

Back  -    New Search

prune belly syndrome (proon) n.

a hereditary condition, occurring exclusively in males, characterized by a deficiency of abdominal muscles, complex malformation of the urinary tract, and bilateral undescended testes. The lungs may be underdeveloped. The name derives from the typically wrinkled appearance of the skin over the abdomen.

Back  -    New Search

prurigo (proor-I-goh) n.

an intensely itchy eruption. Besnier's p. chronic lichenified atopic eczema. nodular p. a condition of unknown cause, usually found in atopic individuals (see ATOPY), in which severely itching nodules mostly occur on the distal limbs. p. of pregnancy prurigo occurring in the middle trimester of pregnancy, affecting mainly the abdomen and the extensor surfaces of the limbs. It may recur in later pregnancies.

Back  -    New Search

pruritus (proor-l-ts) n.

itching; the predominant symptom of atopic eczema, lichen planus, and many other skin diseases. It also occurs in the elderly and may be a manifestation of psychological illness. Perineal itching is common: itching of the vulva in women (p. vulvae ) may be accompanied by itching of the anal region (p. ani ), although the latter is more common in men. Causes of perineal itching include poor hygiene, candidosis, threadworms, and itchy skin diseases (such as eczema).

Back  -    New Search

prussic acid (prus-ik) n.

see HYDROCYANIC ACID.

Back  -    New Search

PSA n.

see PROSTATIC SPECIFIC ANTIGEN.

Back  -    New Search

psammoma (sam-oh-m) n.

a tumour containing gritty sandlike particles (p. bodies ). It is typical of cancer of the ovary but may also be found in the meninges.

Back  -    New Search

pseud- (pseudo-) prefix

denoting superficial resemblance to; false.

Back  -    New Search

pseudarthrosis (nearthrosis) (s'yood-arth-roh-sis) n.

a ‘false’ joint, formed around a displaced bone end after dislocation or between the bone ends of a fracture that fails to unite.

Back  -    New Search

pseudoangina (s'yoo-doh-an-jy-n) n.

pain in the centre of the chest in the absence of heart disease. It is associated with anxiety and may be part of the effort syndrome.

Back  -    New Search

pseudocholinesterase (s'yoo-doh-koh-lin-est-er-ayz) n.

an enzyme found in the blood and other tissues that breaks down acetylcholine, but much more slowly than cholinesterase.

Back  -    New Search

pseudocoxalgia (s'yoo-doh-koks-al-ji) n.

see LEGG-CALVÉ-PERTHES DISEASE.

Back  -    New Search

pseudocrisis (s'yoo-doh-kry-sis) n.

a false crisis: a sudden but temporary fall of temperature in a patient with fever.

Back  -    New Search

pseudocyesis (phantom pregnancy) (s'yoo-doh-sy-ee-sis) n.

a condition in which a nonpregnant woman exhibits symptoms of pregnancy, e.g. enlarged abdomen, morning sickness, and absence of menstruation. The condition usually has an emotional basis.

Back  -    New Search

pseudocyst (s'yoo-doh-sist) n.

a fluid-filled space without a proper wall or lining, within an organ. pancreatic p. a pseudocyst, filled with pancreatic juice, that may develop in cases of chronic pancreatitis or as a complication of acute pancreatitis. It may cause episodes of abdominal pain accompanied by a rise in the level of enzymes in the blood. Treatment is by surgical drainage, usually by marsupialization.

Back  -    New Search

pseudodementia (s'yoo-doh-di-men-sh) n.

1 a condition in which symptoms of dementia, including memory disorders, are caused by depression rather than organic brain disease. It is most commonly seen in elderly depressed individuals.

2 see GANSER STATE.
Top

Back  -    New Search

pseudohermaphroditism (s'yoo-doh-her-maf-r-dyt-izm) n.

a congenital abnormality in which the external genitalia of a male or a female resemble those of the opposite sex.

Back  -    New Search

pseudohypertrophy (s'yoo-doh-hy-per-tr-fi) n.

increase in the size of an organ or structure caused by excessive growth of cells that have a packing or supporting role. The result is usually a decline in the efficiency of the organ.
—pseudohypertrophic (s'yoo-doh-hy-per-trof-ik) adj.

Back  -    New Search

pseudohypoparathyroidism (s'yoo-doh-hy-poh-pa-r-th'y-roid-izm) n.

a syndrome of mental retardation, restricted growth, and bony abnormalities due to a genetic defect that causes lack of response to parathyroid hormone.

Back  -    New Search

pseudologia fantastica (s'yoo-doh-loh-ji fan-tas-tik-) n.

the telling of elaborate and fictitious stories as if they were true. It is sometimes a feature of chronic mental illness and of personality disorders, particularly psychopathy.

Back  -    New Search

Pseudomonas (s'yoo-doh-moh-ns) n.

a genus of rodlike motile pigmented Gramnegative bacteria. Most live in soil and decomposing organic matter. P aeruginosa a species that occurs in pus from wounds; it is associated with urinary tract infections. P. pseudomallei the causative agent of melioidosis.

Back  -    New Search

pseudomyxoma (s'yoo-doh-miks-oh-m) n.

a mucoid tumour of the peritoneum, often seen in association with myxomas of the ovary.

Back  -    New Search

pseudo-obstruction (s'yoo-doh-b-struk-shn) n.

obstruction of the alimentary canal without mechanical narrowing of the bowel. It is usually associated with abnormality of the nerve supply to the muscles of the bowel. See also ILEUS, HIRSCHSPRUNG'S DISEASE.

Back  -    New Search

pseudoplegia (s'yoo-doh-plee-ji) n.

paralysis of the limbs not associated with organic abnormalities. It may be a symptom of conversion disorder.

Back  -    New Search

pseudopodium (s'yoo-doh-poh-dim) n. (pl. pseudopodia)

a temporary and constantly changing extension of the body of an amoeba or an amoeboid cell. Pseudopodia engulf bacteria and other particles as food and are responsible for the movements of the cell.

Back  -    New Search

pseudopolyposis (s'yoo-doh-pol-i-poh-sis) n.

a condition in which the bowel lining (mucosa). It is covered by elevated or protuberant plaques (pseudopolyps ) that are not true polyps but abnormal growth of inflamed mucosa. It is usually found in chronic ulcerative colitis.

Back  -    New Search

pseudoxanthoma elasticum (s'yoo-doh-zanth-oh-mi-lass-tik-m) n.

a hereditary disease in which elastic fibres (see ELASTIC TISSUE) become calcified. The skin becomes lax and yellowish nodules develop in affected areas; this is accompanied by degenerative changes in the blood vessels.

Back  -    New Search

psilosis (sy-loh-sis) n.

see SPRUE.

Back  -    New Search

psittacosis (parrot disease, ornithosis) (sit--koh-sis) n.

an endemic infection of birds, especially parrots, budgerigars, canaries, finches, pigeons, and poultry, caused by the bacterium Chlamydia psittaci. The infection is transmitted to humans by inhalation from handling the birds or by contact with feathers, faeces, or cage dust, but person-to-person transmission also occurs. The symptoms include fever, dry cough, severe muscle pain, and headache; occasionally a severe generalized systemic illness results. The condition responds to tetracycline or erythromycin.

Back  -    New Search

psoas (psoas major) (soh-s) n.

a muscle in the groin that acts jointly with the iliacus muscle to flex the hip joint. A smaller muscle (p. minor ) has the same action but is often absent.

Back  -    New Search

psoralen (sor-ah-ln) n.

see PUVA.

Back  -    New Search

psoriasis (s-ry--sis) n.

a chronic skin disease in which scaly pink patches form on the elbows, knees, scalp, and other parts of the body. Psoriasis is one of the commonest skin diseases in Britain, but its cause is not known. It sometimes occurs in association with arthritis (psoriatic arthritis ). Occasionally the disease may be very severe, affecting much of the skin and causing considerable disability in the patient.
—psoriatic (sor-i-at-ik) adj.

Back  -    New Search

psych- (psycho-) prefix

denoting 1 the mind; psyche.

2 psychology.
Top

Back  -    New Search

psyche (sy-ki) n.

the mind or the soul; the mental (as opposed to the physical) functioning of the individual.

Back  -    New Search

psychedelic (sy-ki-del-ik) adj.

describing drugs, such as cannabis and LSD, that can induce changes in the level of consciousness of the mind.

Back  -    New Search

psychiatrist (si-ky--trist) n.

a medically qualified physician who specializes in the study and treatment of mental disorders.

Back  -    New Search

psychiatry (si-ky--tri) n.

the study of mental disorders and their diagnosis, management, and prevention. —psychiatric (sy-ki-at-rik) adj.

Back  -    New Search

psychic (sy-kik) adj.

1 of or relating to the psyche.

2 relating to parapsychological phenomena.
Top

Back  -    New Search

psychoanalysis (sy-koh--nal-i-sis) n.

a school of psychology and a method of treating mental disorders based upon the teachings of Sigmund Freud (1856–1939). Psychoanalysis employs the technique of free association in the course of intensive psychotherapy in order to bring repressed fears and conflicts to the conscious mind, where they can be dealt with (see REPRESSION).
—psychoanalyst (sy-koh-an--list) n. —psychoanalytic (sy-koh-an--lit-ik) adj.

Back  -    New Search

psychodrama (sy-koh-drah-m) n.

a form of group psychotherapy in which individuals acquire insight into themselves by acting out situations from their past with other group members. See GROUP THERAPY.

Back  -    New Search

psychodynamics (sy-koh-dy-nam-iks) n.

the study of the mind in action.
—psychodynamic adj.

Back  -    New Search

psychogenic (sy-koh-jen-ik) adj.

having an origin in the mind rather than in the body. The term is applied particularly to symptoms and illnesses.

Back  -    New Search

psychogeriatrics (sy-koh-je-ri-at-riks) n.

the branch of psychiatry that deals with the mental disorders of old people.
—psychogeriatric adj.

Back  -    New Search

psychologist (sy-kol--jist) n.

a person who is engaged in the scientific study of the mind. clinical p. a psychologist trained in aspects of the assessment and treatment of the ill and handicapped. He or she usually works in a hospital. educational p. a psychologist trained in aspects of the cognitive and emotional development of children. He or she usually works in close association with schools.

Back  -    New Search

psychology (sy-kol-ji) n.

the science concerned with the study of behaviour and its related mental processes. The different schools of psychology include behaviourism, cognitive psychology, psychoanalysis, and gestaltism.
—psychological (sy-k-loj-ikl) adj.

Back  -    New Search

psychometrics (sy-koh-met-riks) n.

the measurement of individual differences in psychological functions (such as intelligence and personality) by means of standardized tests.
—psychometric adj.

Back  -    New Search

psychomotor (sy-koh-moh-ter) adj.

relating to muscular and mental activity. The term is applied to disorders in which muscular activities are affected by cerebral disturbance.

Back  -    New Search

psychoneuroimmunology (sy-koh-newr-oh-im-yoo-nol-ji) n.

the study of the effects of the mind on the functioning of the immune system, especially in relation to the influence of the mind on susceptibility to disease and the progression of a disease.

Back  -    New Search

psychoneurosis (sy-koh-newr-oh-sis) n.

a neurosis that is manifest in psychological rather than organic symptoms.

Back  -    New Search

psychopath (sy-koh-path) n.

a person who behaves in an antisocial way and shows little or no guilt for antisocial acts and little capacity for forming emotional relationships with others. See also DYSSOCIAL.
—psychopathic adj. —psychopathy (sy-kop--thi) n.

Back  -    New Search

psychopathology (sy-koh-p-thol-ji) n.

1 the study of mental disorders, with the aim of explaining and describing aberrant behaviour. Compare PSYCHIATRY.

2 the symptoms, collectively, of a mental disorder.
Top

—psychopathological adj.

Back  -    New Search

psychopharmacology (sy-koh-farm--kol-ji) n.

the study of the effects of drugs on mental processes and behaviour, particularly psychotropic drugs.

Back  -    New Search

psychophysiology (sy-koh-fiz-i-ol-ji) n.

the branch of psychology that records physiological measurements, such as heart rate and size of the pupil, and relates them to psychological events.
—psychophysiological adj.

Back  -    New Search

psychosexual development (sy-koh-seks-yoo-l) n.

the process by which an individual becomes more mature in his sexual feelings and behaviour. Gender identity, sex-role behaviour, and choice of sexual partner are the three major areas of development.

Back  -    New Search

psychosis (sy-koh-sis) n.

one of a group of mental disorders that feature loss of contact with reality. The psychoses include schizophrenia, major disorders of affect (see MANIC-DEPRESSIVE PSYCHOSIS), major paranoid states, and organic mental disorders. Psychotic disorders may feature delusions, hallucinations, severe thought disturbances, abnormal alteration of mood, poverty of thought, and grossly abnormal behaviour. Many cases of psychotic illness respond well to antipsychotic drugs.
—psychotic (sy-kot-ik) adj.

Back  -    New Search

psychosomatic (sy-koh-s-mat-ik) adj.

relating to or involving both the mind and body: usually applied to illnesses, such as asthma and peptic ulcer, that are caused by the interaction of mental and physical factors.

Back  -    New Search

psychosurgery (sy-koh-ser-jer-i) n.

surgery on the brain to relieve psychological symptoms, such as severe chronic anxiety, depression, and untreatable pain.
—psychosurgical adj.

Back  -    New Search

psychotherapy (sy-koh-th'e-rpi) n.

psychological (as opposed to physical) methods for the treatment of mental disorders and psychological problems. There are many different approaches to psychotherapy, including psychoanalysis, client-centred therapy, group therapy, and family therapy. See also BEHAVIOUR THERAPY, COUNSELLING.
—psychotherapeutic (sy-koh-th'e-r-pew-tik) adj. —psychotherapist n.

Back  -    New Search

psychoticism (sy-kot-i-sizm) n.

a dimension of personality derived from psychometric tests, which appears to indicate a degree of emotional coldness and some cognitive impairment.

Back  -    New Search

psychotropic (sy-koh-trop-ik) adj.

describing drugs that affect mood. Antidepressants, sedatives, stimulants, and tranquillizers are psychotropic.

Back  -    New Search

PTC n.

percutaneous transhepatic cholangiopancreatography: see CHOLANGIOPANCREATOGRAPHY.

Back  -    New Search

pterion (teer-i-n) n.

the point on the side of the skull at which the sutures between the parietal, temporal, and sphenoid bones meet.

Back  -    New Search

pteroylglutamic acid (te-roh-il-gloo-tam-ik) n.

see FOLIC ACID.

Back  -    New Search

pterygium (t-rij-im) n.

a triangular overgrowth of the cornea, usually the inner side, by thickened and degenerative conjunctiva.

Back  -    New Search

pterygo- prefix

denoting the pterygoid process.

Back  -    New Search

pterygoid process (te-ri-goid) n.

either of two large processes of the sphenoid bone.

Back  -    New Search

ptomaine (toh-mayn) n.

any of various substances, such as putrescine, cadaverine, and neurine, produced in decaying foodstuffs and responsible for the unpleasant taste and smell of such foods. Ptomaines themselves are harmless, but they are often associated with toxic bacteria.

Back  -    New Search

ptosis (blepharoptosis) (toh-sis) n.

drooping of the upper eyelid. This may be due to a disorder of the oculomotor nerve, a disease of the eye muscles, or myasthenia gravis; it may also occur as part of Horner's syndrome or as an isolated congenital feature.

Back  -    New Search

-ptosis suffix

denoting a lowered position of an organ or part; prolapse.

Back  -    New Search

PTSD n.

see POST-TRAUMATIC STRESS DISORDER.

Back  -    New Search

ptyal- (ptyalo-) prefix

denoting saliva.

Back  -    New Search

ptyalin (ty--lin) n.

an enzyme (an amylase) found in saliva.

Back  -    New Search

ptyalism (sialorrhoea) (ty--lizm) n.

the excessive production of saliva: a symptom of certain nervous disorders, poisoning, or infection (rabies). Compare DRY MOUTH.

Back  -    New Search

ptyalith (ty--lith) n.

a stone (calculus) in a salivary gland or duct.

Back  -    New Search

ptyalography (ty--log-rfi) n.

see SIALOGRAPHY.

Back  -    New Search

puberty (pew-ber-ti) n.

the time at which the onset of sexual maturity occurs and the reproductive organs become functional. This usually starts in girls at the age of about 12 and in boys at about 14. It is manifested in both sexes by the appearance of secondary sexual characteristics and in girls by the start of menstruation. See also PRECOCIOUS PUBERTY.
—pubertal adj.

Back  -    New Search

pubes (pew-beez) n.

1 the body surface that overlies the pubis, at the front of the pelvis.

2 see PUBIS.
Top

—pubic adj.

Back  -    New Search

pubiotomy (pew-bi-ot-mi) n.

an operation to divide the pubic bone near the symphysis, performed during childbirth to increase the size of an abnormally small pelvis. It is also done to facilitate access to the base of the bladder and the urethra during complex urological procedures.

Back  -    New Search

pubis (pew-bis) n. (pl. pubes)

a bone forming the lower and anterior part of each side of the hip bone (see also PELVIS). The two pubes meet at the front of the pelvis at the pubic symphysis . See also PUBES.

Back  -    New Search

public health medicine (pub-lik) n.

the branch of medicine concerned with assessing needs and trends in health and disease of populations as distinct from individuals. Formerly known as community medicine or social medicine , it includes epidemiology, health promotion, health service planning and evaluation, communicable disease control, and environmental hazards.

Back  -    New Search

public health nurse n.

see HEALTH VISITOR.

Back  -    New Search

public health physician n.

(in Britain) a doctor of consultant status with special postgraduate training in public health medicine, formerly known as a community physician .

Back  -    New Search

pudendal (pew-den-d'l) adj.

relating to the pudendum. p. block anaesthesia of the pudendum and surrounding areas by injecting a local anaesthetic into the nerves that supply them. It is performed to relieve the pain of the expulsive stage of labour. See also NERVE BLOCK. p. nerve the nerve that supplies the lowest muscles of the pelvic floor and the anal sphincter. It is often damaged in childbirth, causing incontinence.

Back  -    New Search

pudendum (pew-den-dm) n. (pl. pudenda)

the external genital organs, especially those of the female (see VULVA).

Back  -    New Search

puerperal (pew-er-per-l) adj.

relating to childbirth or the period that immediately follows it. p. depression a state of pathological sadness that sometimes affects a woman soon after the birth of her baby. In some cases it becomes serious enough to require admission to hospital, where careful supervision and treatment are essential as there is a risk that the woman may kill herself or her baby. p. infection infection of the female genital tract arising as a complication of childbirth. p. pyrexia a temperature of 38°C occurring on any two days within 14 days of childbirth or miscarriage.

Back  -    New Search

puerperium (pew-er-peer-im) n.

the period of up to about six weeks after childbirth, during which the uterus returns to its normal size.

Back  -    New Search

Pulex (pew-leks) n.

a genus of widely distributed fleas. P. irritans the human flea: a common parasite of man whose bite may give rise to intense irritation and bacterial infection.

Back  -    New Search

pulmo-(pulmon(o)-) prefix

denoting the lung(s).

Back  -    New Search

pulmonary (pul-mn-er-i) adj.

relating to, associated with, or affecting the lungs. p. artery the artery that conveys deoxygenated blood from the heart to the lungs for oxygenation. p. capillary wedge pressure (PCWP) pressure of blood in the left atrium of the heart, which indicates the adequacy of the pulmonary circulation. It is measured using a catheter wedged in the most distal segment of the pulmonary artery. p. circulation see CIRCULATION. p. embolism see EMBOLISM. p. hypertension raised blood pressure within the blood vessels supplying the lungs. Pulmonary hypertension may complicate pulmonary embolism, septal defects, heart failure, diseases of the mitral valve, and chronic lung diseases. p. stenosis congenital narrowing of the outlet of the right ventricle of the heart. Severe pulmonary stenosis may produce angina pectoris, faintness, and heart failure. The defect is corrected by surgery. p. surfactant see SURFACTANT. p. tuberculosis see TUBERCULOSIS. p. valve see SEMILUNAR VALVE. p. vein a vein carrying oxygenated blood from the lung to the left atrium.

Back  -    New Search

pulp (pulp) n.

1 a soft mass of tissue (for example, of the spleen).

2 the mass of connective tissue containing blood vessels and nerve fibres at the centre of a tooth (p. cavity )
Top
.
3 the fleshy cushion on the flexor surface of the fingertip.
Top

Back  -    New Search

pulsation (pul-say-shn) n.

a rhythmical throbbing or beating, as of the heart or arteries.

Back  -    New Search

pulse (puls) n.

a series of pressure waves within an artery caused by contractions of the left ventricle and corresponding with the heart rate. It is easily detected over certain superficial arteries (p. points – see illustration). The average adult pulse rate at rest is 60–80 per minute, but exercise, injury, illness, and emotion may produce much faster rates.

Back  -    New Search

pulseless disease (puls-lis) n.

see TAKAYASU'S DISEASE.

Back  -    New Search

pulsus alternans (pul-sus awl-ter-nanz) n.

a pulse in which there is a regular alternation of strong and weak beats without changes in the length of the cycle.

Back  -    New Search

pulsus paradoxus (pa-r-doks-s) n.

a large fall in systolic blood pressure and pulse volume when the patient breathes in. It is seen in constrictive pericarditis, pericardial effusion, and asthma.

Back  -    New Search

pulvis (pul-vis) n.

(in pharmaceutics) a powder.

Back  -    New Search

punch-drunk syndrome n.

a group of symptoms consisting of progressive dementia, tremor of the hands, and epilepsy. It is a consequence of repeated blows to the head that have been severe enough to cause concussion.

Back  -    New Search

punctate (punk-tayt) adj.

spotted or dotted.

Back  -    New Search

punctum (punk-tm) n. (pl. puncta)

(in anatomy) a point or small area. puncta lacrimalia the two openings of the tear ducts in the inner corners of the upper and lower eyelids. See LACRIMAL (APPARATUS).

Back  -    New Search

puncture (punk-cher)

1 n. a wound made accidentally or deliberately by a sharp object or instrument. needle p. a puncture using a hollow needle to withdraw a sample of tissue (especially from the liver, bone marrow, or breast) for examination for diagnostic purposes. See also LUMBAR, (PUNCTURE).

2 vb. to pierce a tissue with a sharp instrument.
Top

Back  -    New Search

pupil (pew-pil) n.

the circular opening in the centre of the iris, through which light passes into the lens of the eye.
—pupillary (pew-pil-er-i) adj.

Back  -    New Search

pupillary reflex (light reflex) n.

the reflex change in the size of the pupil according to the amount of light entering the eye.

Back  -    New Search

purgation (per-gay-shn) n.

the use of drugs to stimulate intestinal activity and clear the bowels. See LAXATIVE.

Back  -    New Search

purgative (per-g-tiv) n.

see LAXATIVE.

Back  -    New Search

purine (pewr-reen) n.

a nitrogenous compound with a two-ring molecular structure. Examples of purines are adenine and guanine, which occur in nucleic acids, and uric acid.

Back  -    New Search

Purkinje cells (per-kin-ji) pl. n.

nerve cells found in great numbers in the cortex of the cerebellum. [J. E. Purkinje (1787–1869), Bohemian physiologist]

Back  -    New Search

Purkinje fibres pl. n.

see ATRIOVENTRICULAR BUNDLE.

Back  -    New Search

purpura (per-pew-r) n.

a skin rash resulting from bleeding into the skin from blood capillaries; the rash is made up of individual purple spots (see PETECHIAE). Purpura may be due either to defects in the blood capillaries (nonthrombocytopenic p. ) or to a deficiency of blood platelets (thrombocytopenic p. ). idiopathic thrombocytopenic p. an autoimmune disease in which the platelets are destroyed, leading to spontaneous bruising. A mild acute form affects children; a more serious chronic form typically affects adults. See also THROMBOCYTOPENIA, HENOCH-SCHÖNLEIN PURPURA.

Back  -    New Search

purulent (pewr-uu-lnt) adj.

forming, consisting of, or containing pus.

Back  -    New Search

pus (pus) n.

a thick yellowish or greenish liquid formed at the site of an established infection. Pus contains dead white blood cells, both living and dead bacteria, and fragments of dead tissue. See also MUCOPUS, SEROPUS.

Back  -    New Search

push-bang technique (puush-bang) n.

a technique for removing a stone from the ureter. It consists of ‘pushing’ the stone back into the renal pelvis, where it can be destroyed by lithotripsy (‘bang’).

Back  -    New Search

pustule (pus-tewl) n.

a small blister on the skin that contains pus.

Back  -    New Search

putamen (pew-tay-men) n.

a part of the lenticular nucleus (see BASAL GANGLIA).

Back  -    New Search

putrefaction (pew-tri-fak-shn) n.

the process whereby proteins are decomposed by bacteria. This is accompanied by the formation of amines (such as putrescine and cadaverine) having a strong and very unpleasant smell.

Back  -    New Search

PUVA (photochemotherapy) n.

psoralen + ultraviolet A: the combination of psoralen , a light-sensitive drug, and exposure to long-wave (315–400 nm) ultraviolet light (UVA). It is principally used for treating psoriasis.

Back  -    New Search

PVS n.

see PERSISTENT VEGETATIVE STATE.

Back  -    New Search

py- (pyo-) prefix

denoting pus; a purulent condition.

Back  -    New Search

pyaemia (py-ee-mi) n.

blood poisoning by pus-forming bacteria released from an abscess. Widespread formation of abscesses may develop, with fatal results. Compare SAPRAEMIA, SEPTICAEMIA, TOXAEMIA.

Back  -    New Search

pyarthrosis (py-arth-roh-sis) n.

an infected joint filled with pus. Drainage, combined with antibiotic treatment, is necessary.

Back  -    New Search

pyel- (pyelo-) prefix

denoting the pelvis of the kidney.

Back  -    New Search

pyelitis (py--ly-tis) n.

inflammation of the pelvis of the kidney, usually caused by a bacterial infection. The patient experiences pain in the loins, shivering, and a high temperature. Treatment is by the administration of a suitable antibiotic, together with analgesics and a high fluid intake.

Back  -    New Search

pyelocystitis (py--loh-sis-ty-tis) n.

inflammation of the renal pelvis and urinary bladder (see PYELITIS, CYSTITIS).

Back  -    New Search

pyelogram (py--loh-gram) n.

an X-ray picture obtained by pyelography.

Back  -    New Search

pyelography (urography) (py--log-rfi) n.

X-ray examination of the kidneys using radiopaque contrast material. intravenous p. (excretion urography ) pyelography in which the contrast medium is injected into a vein and is concentrated and excreted by the kidneys. retrograde p. pyelography in which fine catheters are passed up the ureter to the kidneys at cystoscopy and contrast material is injected directly into the renal pelvis.

Back  -    New Search

pyelolithotomy (py--loh-lith-ot-mi) n.

surgical removal of a stone from the kidney through an incision made in the pelvis of the kidney.

Back  -    New Search

pyelonephritis (py--loh-ni-fry-tis) n.

bacterial infection of the kidney substance. acute p. pyelonephritis in which the patient has pain in the loins, a high temperature, and shivering fits. Treatment is by the administration of an appropriate antibiotic. chronic p. pyelonephritis in which the kidneys become small and scarred and kidney failure ensues. Vesicoureteric reflux in childhood is one of the causes.

Back  -    New Search

pyeloplasty (py--loh-plasti) n.

an operation to relieve obstruction at the junction of the pelvis of the kidney and the ureter. See HYDRONEPHROSIS, DIETL'S CRISIS.

Back  -    New Search

pyelotomy (py--lot-mi) n.

surgical incision into the pelvis of the kidney. This operation is usually undertaken to remove a stone (see PYELOLITHOTOMY).

Back  -    New Search

pyg- (pygo-) prefix

denoting the buttocks.

Back  -    New Search

pykno- prefix

denoting thickness or density.

Back  -    New Search

pyknolepsy (pik-noh-lep-si) n.

Obsolete. a very high frequency of absence attacks (see EPILEPSY).

Back  -    New Search

pyl- (pyle-) prefix

denoting the portal vein.

Back  -    New Search

pylephlebitis (portal pyaemia) (py-li-fli-by-tis) n.

septic inflammation and thrombosis of the hepatic portal vein, resulting from the spread of infection within the abdomen. The condition causes fever, liver abscesses, and ascites. Treatment is by antibiotic drugs and surgical drainage of abscesses.

Back  -    New Search

pylethrombosis (py-li-throm-boh-sis) n.

obstruction of the portal vein by a blood clot (see THROMBOSIS), resulting from such conditions as pylephlebitis and cirrhosis of the liver. Portal hypertension is a frequent result.

Back  -    New Search

pylor- (pyloro-) prefix

denoting the pylorus.

Back  -    New Search

pylorectomy (py-lor-ek-tmi) n.

a surgical operation in which the muscular outlet of the stomach (pylorus) is removed. See ANTRECTOMY, PYLOROPLASTY.

Back  -    New Search

pyloric stenosis (py-lor-ik) n.

narrowing of the pylorus. This causes delay in passage of the stomach contents to the duodenum, which leads to repeated vomiting. Pyloric stenosis in adults is caused by a peptic ulcer close to the pylorus or by a cancerous growth invading it. congenital hypertrophic p. s. pyloric stenosis that occurs in babies about 3–5 weeks old (particularly boys) in which the thickened pyloric muscle can be felt as a nodule. Treatment is by pyloromyotomy.

Back  -    New Search

pyloromyotomy (Ramstedt's operation) (py-lor-oh-my-ot-mi) n.

a surgical operation in which the muscle around the pylorus is divided down to the lining (mucosa) in order to relieve congenital pyloric stenosis.

Back  -    New Search

pyloroplasty (py-lor-oh-plasti) n.

a surgical operation in which the pylorus is widened by a form of reconstruction. It is done to allow the contents of the stomach to pass more easily into the duodenum.

Back  -    New Search

pylorospasm (py-lor-oh-spazm) n.

closure of the pylorus due to muscle spasm, leading to delay in the passage of stomach contents to the duodenum and vomiting. It is usually associated with duodenal or pyloric ulcers.

Back  -    New Search

pylorus (py-lor-s) n.

the lower end of the stomach, which leads to the duodenum. It terminates at a ring of muscle (pyloric sphincter ), which contracts to close the opening by which the stomach communicates with the duodenum.
—pyloric adj.

Back  -    New Search

pyo- prefix.

see PY-.

Back  -    New Search

pyocele (py-oh-seel) n.

a swelling caused by an accumulation of pus in a part of the body.

Back  -    New Search

pyocolpos (py-oh-kol-pos) n.

the presence of pus in the vagina.

Back  -    New Search

pyocyanin (py-oh-sy--nin) n.

an antibiotic substance produced by the bacterium Pseudomonas aeruginosa. It is used in medicine principally to attack Gram-positive bacteria.

Back  -    New Search

pyoderma gangrenosum (py-oh-der-m gang-ri-noh-sm) n.

an acute destructive ulcerating process of the skin, especially the legs. It may be associated with ulcerative colitis or Crohn's disease or with rheumatoid arthritis or other forms of arthritis affecting many joints.

Back  -    New Search

pyogenic (py-oh-jen-ik) adj.

causing the formation of pus. p. granuloma a common rapidly growing nodule on the surface of the skin. Resembling a redcurrant or (if large) a raspberry, it is composed of small blood vessels and therefore bleeds readily after the slightest injury.

Back  -    New Search

pyometra (py-oh-mee-tr) n.

the presence of pus in the uterus.

Back  -    New Search

pyomyositis (py-oh-my-oh-sy-tis) n.

bacterial or fungal infection of a muscle resulting in painful inflammation.

Back  -    New Search

pyonephrosis (py-oh-ni-froh-sis) n.

obstruction and infection of the kidney resulting in pus formation. A kidney stone is the usual cause of the obstruction, and the kidney becomes distended by pus and destroyed by the inflammation. Treatment is urgent nephrectomy under antibiotic cover.

Back  -    New Search

pyopericarditis (py-oh-pe-ri-kar-dy-tis) n.

inflammation of the pericardium, with the formation of pus.

Back  -    New Search

pyopneumothorax (py-oh-new-moh-thor-aks) n.

pus and gas or air in the pleural cavity. The condition can arise if air is introduced during attempts to drain the pus from an empyema. Alternatively a hydropneumothorax may become infected.

Back  -    New Search

pyorrhoea (py--ree-) n.

a former name for periodontal disease.

Back  -    New Search

pyosalpinx (py-oh-sal-pinks) n.

the accumulation of pus in a Fallopian tube.

Back  -    New Search

pyosis (py-oh-sis) n.

the formation and discharge of pus.

Back  -    New Search

pyothorax (py-oh-thor-aks) n.

see EMPYEMA.

Back  -    New Search

pyr- (pyro-) prefix

denoting 1 fire.

2 a burning sensation.
Top

3 fever.
Top

Back  -    New Search

pyramid (pi-r-mid) n.

1 one of the conical masses that make up the medulla of the kidney.

2 one of the elongated bulging areas on the anterior surface of the medulla oblongata in the brain.
Top

—pyramidal (pi-ram-i-d'l) adj.

Back  -    New Search

pyramidal cell n.

a type of neurone found in the cerebral cortex, with a pyramid-shaped cell body.

Back  -    New Search

pyramidal system n.

a collection of nerve tracts within the pyramid of the medulla oblongata, en route from the cerebral cortex to the spinal cord.

Back  -    New Search

pyrantel (py-ran-tel) n.

an anthelmintic drug used to treat infestations with intestinal worms, especially roundworms and pinworms. It is administered by mouth. Trade names: Antiminth , Combantrin .

Back  -    New Search

pyrazinamide (py-r-zin--myd) n.

a drug administered by mouth, usually in combination with other drugs, to treat tuberculosis. Trade name: Zinamide .

Back  -    New Search

pyret- (pyreto-) prefix

denoting fever.

Back  -    New Search

pyrexia (py-reks-i) n.

see FEVER.

Back  -    New Search

pyridostigmine (pi-ri-doh-stig-meen) n.

a drug that inhibits the enzyme cholinesterase and is used to treat myasthenia gravis. It has a more prolonged action and is less toxic than neostigmine.

Back  -    New Search

pyridoxal phosphate (pi-ri-doks-l) n.

a derivative of vitamin B_6 that is an important coenzyme in certain reactions of amino-acid metabolism. See TRANSAMINATION.

Back  -    New Search

pyridoxine (vitamin B_6) (pi-ri-doks-een) n.

see VITAMIN B.

Back  -    New Search

pyrimethamine (pi-ri-meth--meen) n.

a drug administered by mouth for the prevention and treatment of malaria, either alone or in combination with dapsone; it is also used in the treatment of toxoplasmosis. Trade name: Daraprim .

Back  -    New Search

pyrimidine (pi-rim-i-deen) n.

a nitrogen-containing compound with a ring molecular structure. The commonest pyrimidines are cytosine, thymine, and uracil, which form the nucleotides of nucleic acids.

Back  -    New Search

pyrogen (py-roh-jen) n.

any substance or agent producing fever.
—pyrogenic adj.

Back  -    New Search

pyromania (py-roh-may-ni) n.

an excessively strong impulse to set things on fire.
—pyromaniac adj., n.

Back  -    New Search

pyrosis (py-roh-sis) n.

another term (chiefly US) for heartburn.

Back  -    New Search

pyruvic acid (pyruvate) (py-roo-vik) n.

a compound, derived from carbohydrates, that may be oxidized in the Krebs cycle to yield carbon dioxide and energy in the form of ATP.

Back  -    New Search

pyuria (py-yoor-i) n.

the presence of pus in the urine, making it cloudy. This is a sign of bacterial infection in the urinary tract.

Back  -    New Search

Q

Q fever n.

an acute infectious disease of many animals, including cattle, sheep, goats, deer, and dogs, that is caused by a rickettsia, Coxiella burnetii. It is transmitted to man primarily through inhalation of infected particles or consumption of contaminated unpasteurized milk, but also via ticks acting as vectors. A severe influenza-like illness develops, sometimes with pneumonia, after an incubation period of up to three weeks. Treatment with tetracyclines or chloramphenicol is effective. See also TYPHUS.

Back  -    New Search

QRS complex n.

the element of an electrocardiogram that precedes the S-T segment and indicates ventricular contraction.

Back  -    New Search

Q-T interval n.

the interval on an electrocardiogram that contains the deflections produced by ventricular contraction.

Back  -    New Search

quadratus (kwod-ray-ts) n.

any of various four-sided muscles. q. femoris a flat muscle at the head of the femur, responsible for lateral rotation of the thigh.

Back  -    New Search

quadri- prefix

denoting four.

Back  -    New Search

quadriceps (kwod-ri-seps) n.

one of the great extensor muscles of the legs. It is situated in the thigh and is subdivided into four distinct portions: the rectus femoris , vastus lateralis , vastus medialis , and vastus intermedius .

Back  -    New Search

quadriplegia (tetraplegia) (kwod-ri-plee-ji) n.

paralysis affecting all four limbs.
—quadriplegic adj., n.

Back  -    New Search

quadruple vaccine (kwod-roo-pl) n.

a combined vaccine used to produce immunity against diphtheria, whooping cough, poliomyelitis, and tetanus.

Back  -    New Search

quality assurance (kwol-iti -shor-ns) n.

a programme used in health-care services as a means of measuring the satisfaction of consumers for services given by all professional disciplines. See NURSING AUDIT, PERFORMANCE INDICATORS. q. a. tool a model used by nurses to measure the quality of nursing care. It involves observation of patients, listening to reports, reviewing the care plans, and then scoring to a predetermined schedule (such as qualpacs or Monitor ).

Back  -    New Search

quality circle n.

a strategy utilized to develop and maintain nursing standards. It relies heavily on enthusiastic representatives from all disciplines participating in the process of standard development, in order to foster a personal commitment to a quality service.

Back  -    New Search

qualpacs (kwol-paks) n.

see QUALITY ASSURANCE (TOOL).

Back  -    New Search

quantitative digital radiography (kwon-ti-t-tiv dij-i-t'l) n.

a method of detecting osteoporosis. A narrow X-ray beam is directed at the area of interest (usually the spine and hip), which enables a measurement to be made of its calcium content (density).

Back  -    New Search

quarantine (kwo-rn-teen) n.

the period for which a person (or animal) is kept in isolation to prevent the spread of a contagious disease. Different diseases have different quarantine periods.

Back  -    New Search

quartan fever (kwor-t'n) n.

a type of malaria, caused by Plasmodium malariae, in which there is a three-day interval between fever attacks.

Back  -    New Search

Queckenstedt test (kwek-n-stet) n.

a part of the routine lumbar puncture procedure. It is used to determine whether or not the flow of cerebrospinal fluid is blocked in the spinal cord. [H. H. G. Queckenstedt (1876–1918), German physician]

Back  -    New Search

quickening (kwik-n-ing) n.

the first movement of a fetus in the uterus that is felt by the mother, usually after about 16 weeks of pregnancy.

Back  -    New Search

quiescent (kwi-es-nt) adj.

describing a disease that is in an inactive or undetectable phase.

Back  -    New Search

quinestradol (kwin-ee-str-dol) n.

a synthetic female sex hormone (see OESTROGEN) administered by mouth to treat inflammation of the vagina, particularly after the menopause. Trade name: Pentovis .

Back  -    New Search

quinestrol (kwin-ee-strol) n.

a synthetic female sex hormone (see OESTROGEN) administered by mouth to inhibit lactation in mothers not breast feeding. Trade name: Estrovis .

Back  -    New Search

quinidine (kwin-i-deen) n.

a drug that slows down the activity of the heart and is administered by mouth to control abnormal and increased heart rhythm. Trade names: Kinitard , Kinidin Durules .

Back  -    New Search

quinine (kwin-een) n.

a drug used to prevent and treat malaria, now largely replaced by more effective less toxic drugs except in cases of malaria due to Plasmodium falciparum. Small doses of quinine are used to treat muscular cramps. It is administered by mouth or injection; large doses can cause severe poisoning (see CINCHONISM).

Back  -    New Search

quinism (kwin-izm) n.

the symptoms of overdosage or too prolonged treatment with quinine. See CINCHONISM.

Back  -    New Search

quinolone (kwin--lohn) n.

one of a group of chemically related synthetic antibiotics that includes ciprofloxacin, nalidixic acid, and ofloxacin. These drugs are often useful for treating infections with organisms that have become resistant to other antibiotics. They are administered by mouth.

Back  -    New Search

quinsy (kwin-zi) n.

pus in the space between the tonsil and the wall of the pharynx. The patient has severe pain with difficulty in opening the mouth (trismus) and swallowing. Treatment is with antibiotics; surgical incision of the abscess may be necessary. Medical name: peritonsillar abscess .

Back  -    New Search

quotidian fever (kwoh-tid-in) n.

a severe type of malaria, caused by Plasmodium falciparum, in which the interval between fever attacks varies from a few hours to two days.

Back  -    New Search

quotient (kwoh-shnt) n.

see INTELLIGENCE QUOTIENT, RESPIRATORY QUOTIENT.

Back  -    New Search

Q wave n.

the downward deflection on an electrocardiogram that indicates the beginning of ventricular contraction.

Back  -    New Search

R

rabbit fever (rab-it) n.

see TULARAEMIA.

Back  -    New Search

rabies (hydrophobia) (ray-beez) n.

an acute virus disease of the central nervous system that may be transmitted to man by a bite from an infected dog. Symptoms include malaise, fever, difficulty in breathing, salivation, and painful muscle spasms of the throat induced by swallowing. In the later stages of the disease the mere sight of water induces convulsions and paralysis; death occurs within 4–5 days. Injections of rabies vaccine and antiserum may prevent the disease from developing in a person bitten by an infected animal.
—rabid (rab-id) adj.

Back  -    New Search

racemose (ras-i-mohs) adj.

resembling a bunch of grapes. The term is applied particularly to a compound gland the secretory part of which consists of a number of small sacs.

Back  -    New Search

rachi- (rachio-) prefix

denoting the spine.

Back  -    New Search

rachis (ray-kis) n.

see BACKBONE.

Back  -    New Search

rachischisis (ray-kis-ki-sis) n.

see SPINA BIFIDA.

Back  -    New Search

rachitic (r-kit-ik) adj.

afflicted with rickets.

Back  -    New Search

rad (rad) n.

a former unit of absorbed dose of ionizing radiation. It has been replaced by the gray.

Back  -    New Search

radial (ray-di-l) adj.

relating to or associated with the radius. r. artery a branch of the brachial artery, beginning at the elbow and passing down the forearm, around the wrist, and into the palm of the hand. r. nerve an important mixed sensory and motor nerve of the arm, forming the largest branch of the brachial plexus. r. reflex flexion of the forearm (and sometimes also of the fingers) that occurs when the lower end of the radius is tapped.

Back  -    New Search

radiation (ray-di-ay-shn) n.

energy in the form of waves or particles, such as gamma rays, X-rays, ultraviolet rays, visible light, and infrared rays (radiant heat). r. sickness an acute illness caused by extreme exposure to rays emitted by radioactive substances, e.g. X-rays or gamma rays. Very high doses cause death within hours. Lower doses cause immediate symptoms of nausea, vomiting, and diarrhoea followed by damage to the bone marrow, loss of hair, and bloody diarrhoea.

Back  -    New Search

radical treatment (rad-ikl) n.

vigorous treatment that aims at the complete cure of a disease rather than the mere relief of symptoms. Compare CONSERVATIVE TREATMENT.

Back  -    New Search

radicle (rad-ikl) n.

(in anatomy) 1 a small root.

2 the initial fibre of a nerve or the origin of a vein.
Top

—radicular (r-dik-yoo-ler) adj.

Back  -    New Search

radiculitis (r-dik-yoo-ly-tis) n.

inflammation of the root of a nerve. See POLYRADICULITIS.

Back  -    New Search

radio-prefix

denoting 1 radiation.

2 radioactive substances.
Top

Back  -    New Search

radioactivity (ray-di-oh-ak-tiv-iti) n.

disintegration of the nuclei of certain elements, with the emission of energy in the form of alpha, beta, or gamma rays. Naturally occurring radioactive elements include radium and uranium. See also RADIOISOTOPE.
—radioactive adj.

Back  -    New Search

radioautography (ray-di-oh-aw-tog-rfi) n.

see AUTORADIOGRAPHY.

Back  -    New Search

radiobiology (ray-di-oh-by-ol-ji) n.

the study of the effects of radiation on living tissues.
—radiobiologist n.

Back  -    New Search

radiodermatitis (ray-di-oh-der-m-ty-tis) n.

inflammation of the skin after exposure to ionizing radiation. The skin becomes dry, hairless, and atrophied, losing its colouring.

Back  -    New Search

radiographer (ray-di-og-r-fer) n.

a person who is trained in the technique either of taking X-ray pictures of parts of the body (diagnostic r. ) or of treatment by radiotherapy (therapeutic r. ).

Back  -    New Search

radiography (ray-di-og-rfi) n.

diagnostic radiology: the technique of examining the body by directing X-rays through it to produce images (radiographs ) on photographic plates or fluorescent screens. Radiography is used in the diagnosis of such disorders as broken bones, gastric ulcers, and gallstones, when inspection from outside the body is insufficient for diagnosis. digital r. the application of digitization to conventional radiography, allowing the storage of images on hard disk and their subsequent retrieval and interpretation using TV monitors.

Back  -    New Search

radioimmunoassay (ray-di-oh-im-yoo-noh-ass-ay) n.

the technique of using radioactive tracers to estimate the levels of natural substances, especially hormones, in the blood through their ability to act as antigens or antibodies and bind to the labelled material.

Back  -    New Search

radioimmunolocalization (ray-di-oh-im-yoo-noh-loh-kl-l-zay-shn) n.

a method of identifying the site of a tumour (e.g. colorectal cancer) that relies on its uptake of radioactive isotopes attached to an appropriate anticancer immune cell.

Back  -    New Search

radioisotope (ray-di-oh-l-s-tohp) n.

an isotope of an element that emits alpha, beta, or gamma radiation during its decay into another element. Artificial radioisotopes, such as iodine-131 and cobalt-60, are produced by bombarding elements with beams of neutrons. They are widely used in medicine as tracers and as sources of radiation for the different techniques of radiotherapy.

Back  -    New Search

radiologist (ray-di-ol--jist) n.

a doctor specialized in the interpretation of X-rays and other scanning techniques for the diagnosis of disease.

Back  -    New Search

radiology (ray-di-ol-ji) n.

the branch of medicine concerned with the use of radiation, including X-rays, and radioactive substances in the diagnosis and treatment of disease. diagnostic r. see RADIOGRAPHY. interventional r. an application of radiology whereby therapeutic or diagnostic procedures can be performed under direct radiological vision. It is used in many forms of minimally invasive surgery. therapeutic r. see RADIOTHERAPY.

Back  -    New Search

radionuclide (ray-di-oh-new-klyd) n.

a radioactive atomic nucleus used to label tracers for diagnosis in nuclear medicine.

Back  -    New Search

radiopaque (ray-di-oh-oh-payk) adj.

having the property of absorbing, and therefore being opaque to, X-rays. Radiopaque materials, such as those containing iodine or barium, are used as contrast media in radiography.

Back  -    New Search

radio pill (ray-di-oh) n.

a capsule containing a miniature radio transmitter that can be swallowed by a patient. During its passage through the digestive tract a radio pill transmits information about internal conditions (acidity, etc.).

Back  -    New Search

radiosensitive (ray-di-oh-sen-sit-iv) adj.

describing certain forms of cancer cell that are particularly susceptible to radiation and are likely to be dealt with successfully by radiotherapy.

Back  -    New Search

radiosensitizer (ray-di-oh-sen-sit-l-zer) n.

a substance that increases the sensitivity of cells to radiation. The presence of oxygen and other compounds with a high affinity for electrons will increase radiosensitivity.

Back  -    New Search

radiotherapist (ray-di-oh-th'e-r-pist) n.

a doctor who specializes in treatment with radiotherapy.

Back  -    New Search

radiotherapy (ray-di-oh-th'e-rpi) n.

therapeutic radiology: the treatment of disease with penetrating radiation, such as X-rays, beta rays, or gamma rays. Beams of radiation may be directed at a diseased part from a distance (see TELECURIETHERAPY), or radioactive material, in the form of needles, wires, or pellets, may be implanted in the body.

Back  -    New Search

radium (ray-dim) n.

a radioactive metallic element that emits alpha and gamma rays during its decay into other elements. The gamma radiation is employed in radiotherapy for the treatment of cancer. Symbol: Ra. See also THORIUM-X.

Back  -    New Search

radius (ray-di-s) n.

the outer and shorter bone of the forearm (compare ULNA). It partially revolves about the ulna, permitting pronation and supination of the hand.
—radial adj.

Back  -    New Search

radix (ray-diks) n.

see ROOT.

Back  -    New Search

radon (ray-don) n.

a radioactive gaseous element that is produced during the decay of radium. It emits alpha and gamma radiation. Symbol: Rn. r. seeds sealed capsules containing radon, used in radiotherapy for the treatment of cancer.

Back  -    New Search

rale (rahl) n.

see CREPITATION.

Back  -    New Search

Ramstedt's operation (rahm-stets) n.

see PYLOROMYOTOMY. [W. C. Ramstedt (1867–1963), German surgeon]

Back  -    New Search

ramus (ray-ms) n. (pl. rami)

1 a branch, especially of a nerve fibre or blood vessel.

2 a thin process projecting from a bone.
Top

Back  -    New Search

ranitidine (ra-nit-i-deen) n.

an antihistamine drug that inhibits gastric secretion and is used in the treatment of gastric and duodenal ulcers and reflux oesophagitis. It may be administered by mouth, intravenously, or intramuscularly. Trade name: Zantac .

Back  -    New Search

ranula (ran-yoo-l) n.

a cyst found under the tongue, formed when the duct leading from a salivary or mucous gland is obstructed and distended.

Back  -    New Search

raphe (ray-fi) n.

a line, ridge, seam, or crease in a tissue or organ; for example, the furrow that passes down the centre of the dorsal surface of the tongue.

Back  -    New Search

rarefaction (rair-i-fak-shn) n.

thinning of bony tissue sufficient to cause decreased density of bone to X-rays, as in osteoporosis.

Back  -    New Search

rash (rash) n.

a temporary eruption on the skin, usually typified by reddening, which may be accompanied by itching. A rash may be a local skin reaction or the outward sign of a disorder affecting the body.

Back  -    New Search

raspatory (rah-sp-ter-i) n.

a filelike surgical instrument used for scraping the surface of bone.

Back  -    New Search

raspberry tumour (rahz-be-ri) n.

an adenoma of the umbilicus.

Back  -    New Search

rat-bite fever (sodokosis) (rat-byt) n.

a disease, contracted from the bite of a rat, due to infection by either the bacterium Spirillum minus, which causes ulceration of the skin and recurrent fever, or by the fungus Streptobacillus moniliformis, which causes inflammation of the skin, muscular pains, and vomiting. Both infections respond well to penicillin.

Back  -    New Search

rationalization (rash-n--ly-zay-shn) n.

(in psychiatry) the explanation of events or behaviour in terms that avoid giving the true reasons.

Back  -    New Search

rauwolfia (raw-wuul-fi) n.

the dried root of the shrub Rauwolfia serpentina, which contains several alkaloids, including reserpine. Rauwolfia and its alkaloids lower blood pressure and depress activity of the central nervous system.

Back  -    New Search

Raynaud's disease (ray-nohz) n.

a condition of unknown cause in which the arteries of the fingers are unduly reactive and enter spasm when the hands are cold. This produces attacks of pallor, numbness, and discomfort in the fingers. Gangrene or ulceration of the fingertips may result. Warm gloves and antispasmodic drugs may relieve the condition. [M. Raynaud (1834–81), French physician]

Back  -    New Search

reaction (ri-ak-shn) n.

1 the response to a stimulus.

2 the interaction of two or more substances that results in chemical changes in them.
Top

3 the effect produced by an allergen (see ALLERGY).
Top

Back  -    New Search

reactive (ri-ak-tiv) adj.

describing mental illnesses that are precipitated by events in the psychological environment.

Back  -    New Search

reagent (ree-ay-jnt) n.

a compound that reacts with another, especially one used to detect the presence of the other compound.

Back  -    New Search

reagin (ree--jin) n.

a type of antibody, formed against an allergen, that remains fixed in various tissues. Subsequent contact with the allergen causes damage to the tissue and the release of histamine and serotonin, which are responsible for the allergic reaction (see ANAPHYLAXIS).

Back  -    New Search

real-time imaging (reel-tym) n.

the rapid acquisition and manipulation of ultrasound information from a scanning probe by electronic circuits to enable images to be produced on TV screens almost instantaneously. Using similar techniques, the instantaneous display of other imaging modalities, such as CT scanning and magnetic resonance imaging, can now be achieved.

Back  -    New Search

recall (ri-kawl)

1 n. the process of eliciting a representation (especially an image) of a past experience.

2 vb. to elicit such a representation.
Top

Back  -    New Search

receptaculum (ree-sep-tak-yoo-lm) n.

the dilated portion of a tubular anatomical part. r. (or cisterna ) chyli the dilated end of the thoracic duct, into which lymph vessels from the lower limbs and intestines drain.

Back  -    New Search

receptor (ri-sep-ter) n.

1 a cell or group of cells specialized to detect changes in the environment and trigger impulses in the sensory nervous system. All sensory nerve endings act as receptors. See EXTEROCEPTOR, INTEROCEPTOR, PROPRIOCEPTOR.

2 a specialized area of cell membrane that can bind with a specific hormone (e.g. oestrogen r. ), neurotransmitter (e.g. adrenergic r. ), drug, or other chemical, thereby initiating a change within the cell.
Top

Back  -    New Search

recess (ri-ses) n.

(in anatomy) a hollow chamber or a depression in an organ or other part.

Back  -    New Search

recessive (ri-ses-iv) adj.

describing a gene (or its corresponding characteristic) whose effect is shown in the individual only when its allele is the same, i.e. when two such alleles are present (the double recessive condition). Compare DOMINANT. See also AUTOSOMAL.
—recessive n.

Back  -    New Search

recipient (ri-sip-int) n.

a person who receives something from a donor, such as a blood transfusion or a kidney transplant.

Back  -    New Search

recombinant DNA (ri-kom-bin-nt) n.

DNA that contains genes from different sources that have been combined by the techniques of genetic engineering. Genetic engineering is therefore also known as recombinant DNA technology .

Back  -    New Search

recrudescence (ree-kroo-des-ns) n.

a fresh outbreak of a disorder in a patient after a period during which its signs and symptoms had died down.

Back  -    New Search

rect- (recto-) prefix

denoting the rectum.

Back  -    New Search

rectocele (rek-toh-seel) n.

see PROCTOCELE.

Back  -    New Search

rectopexy (rek-toh-peks-i) n.

the surgical fixation of a prolapsed rectum.

Back  -    New Search

rectosigmoid (rek-toh-sig-moid) n.

the region of the large intestine around the junction of the sigmoid colon and the rectum.

Back  -    New Search

rectovesical (rek-toh-ves-ikl) adj.

relating to the rectum and the urinary bladder.

Back  -    New Search

rectum (rek-tm) n.

the terminal part of the large intestine, which runs from the sigmoid colon to the anal canal. Faeces are stored in the rectum before defecation.
—rectal (rek-t'l) adj.

Back  -    New Search

rectus (rek-ts) n.

any of several straight muscles. r. abdominis a long flat muscle that extends bilaterally along the entire length of the front of the abdomen. r. femoris see QUADRICEPS. r. muscles of the orbit some of the extrinsic eye muscles.

Back  -    New Search

recumbent (ri-kum-bnt) adj.

lying down.
—recumbency n.

Back  -    New Search

recurrent (ri-ku-rnt) adj.

(in anatomy) describing a structure, such as a nerve or blood vessel, that turns back on its course, forming a loop.

Back  -    New Search

red blood cell n.

see ERYTHROCYTE.

Back  -    New Search

red lotion n.

an astringent solution containing zinc sulphate.

Back  -    New Search

reduction (ri-duk-shn) n.

(in surgery) the restoration of a displaced part of the body, such as a hernia or a dislocated joint, to its normal position by manipulation or operation.

Back  -    New Search

reduction division n.

the first division of meiosis, in which the chromosome number is halved.

Back  -    New Search

referred pain (synalgia) (ri-ferd) n.

pain felt in a part of the body other than where it might be expected. An abscess beneath the diaphragm, for example, may cause a referred pain in the shoulder area. The confusion arises because sensory nerves from different parts of the body share common pathways when they reach the spinal cord.

Back  -    New Search

reflex (ree-fleks) n.

an automatic or involuntary response to a stimulus, which is brought about by relatively simple nervous circuits without consciousness being necessarily involved. See CONDITIONED REFLEX, MORO REFLEX, PATELLAR REFLEX, PLANTAR (REFLEX), PUPILLARY REFLEX, ROOTING REFLEX. r. arc the nervous circuit involved in a reflex, being at its simplest a sensory nerve with a receptor, linked at a synapse in the brain or spinal cord with a motor nerve, which supplies a muscle or gland. See illustration.

Back  -    New Search

reflux (ree-fluks) n.

a backflow of liquid, against its normal direction of movement. See GASTRO-OESOPHAGEAL REFLUX, (REFLUX) OESOPHAGITIS, VESICOURETERIC REFLUX.

Back  -    New Search

refraction (ri-frak-shn) n.

1 the change in direction of light rays when they pass obliquely from one transparent medium to another, of a different density. Refraction occurs as light enters the eye and passes through the cornea, lens, etc., to come to a focus on the retina. Errors of refraction include astigmatism and long-and short-sightedness.

2 determination of the power of refraction of the eye. This determines whether or not the patient needs glasses and, if so, how strong they should be.
Top

Back  -    New Search

refractometer (ree-frak-tom-it-er) n.

see OPTOMETER.

Back  -    New Search

refractory (ri-frakt-er-i) adj.

unresponsive: applied to a condition that fails to respond satisfactorily to a given treatment.

Back  -    New Search

refractory period n.

(in neurology) the time of recovery needed for a nerve cell that has just transmitted a nerve impulse or for a muscle fibre that has just contracted. During the refractory period a normal stimulus will not bring about excitation of the cell.

Back  -    New Search

refrigeration (ri-frij-er-ay-shn) n.

lowering the temperature of a part of the body to reduce the metabolic activity of its tissues or to provide a local anaesthetic effect.

Back  -    New Search

regeneration (ri-jen-er-ay-shn) n.

the natural regrowth of a tissue or other part lost through injury.

Back  -    New Search

regimen (rej-i-men) n.

(in therapeutics) a prescribed systematic form of treatment, such as a diet or a course of drugs, for curing disease or improving health.

Back  -    New Search

regional ileitis (ree-jn-l) n.

see CROHN'S DISEASE.

Back  -    New Search

registered nurse (rej-is-terd) n.

see NURSE.

Back  -    New Search

registrar (specialist registrar) (rej-i-strar) n.

(in a hospital) a registered doctor who undergoes a training programme in a chosen specialty in order to obtain a Certificate of Completion of Specialist Training and be eligible to apply for a consultant post. The post of specialist registrar replaced those of registrar and senior registrar .

Back  -    New Search

regression (ri-gresh-n) n.

1 (in psychiatry) reversion to a more immature level of functioning.

2 the stage of a disease during which the signs and symptoms disappear and the patient recovers.
Top

Back  -    New Search

regurgitation (ri-ger-ji-tay-shn) n.

1 the bringing up of undigested material from the stomach to the mouth (see VOMITING).

2 the flowing back of a liquid in a direction opposite to the normal one.
Top

Back  -    New Search

rehabilitation (ree--bil-i-tay-shn) n.

1 (in physical medicine) the treatment of an ill, injured, or disabled patient with the aim of restoring normal health and function.

2 any means for restoring the independence of a patient after disease or injury.
Top

Back  -    New Search

Reiter's syndrome (ry-terz) n.

a condition characterized by urethritis, conjunctivitis, and arthritis. No causative agent has been positively identified, although a virus may be implicated. [H. Reiter (1881–1969), German physician]

Back  -    New Search

rejection (ri-jek-shn) n.

(in transplantation) the destruction by immune mechanisms of a tissue grafted from another individual. Antibodies, complement, clotting factors, and platelets are involved in the failure of the graft to survive. Homograft rejection is a vigorous response that can be modified by drugs, such as cyclosporin A; heterograft rejection is a violent acute response that is at present beyond therapeutic control.

Back  -    New Search

relapse (ri-laps) n.

a return of disease symptoms after recovery had apparently been achieved or the worsening of an apparently recovering patient's condition.

Back  -    New Search

relapsing fever (ri-laps-ing) n.

an infectious disease caused by bacteria of the genus Borrelia, which is transmitted by ticks or lice and results in recurrent fever. The first episode of fever is accompanied by severe headache and aching muscles and joints. Subsequent attacks are milder and occur at intervals of 3–10 days. Treatment with antibiotics is effective.

Back  -    New Search

relative density (rel--tiv) n.

the ratio of the density of a substance at a specified temperature to the density of a reference substance (for liquids, this is water at 4°C). It was formerly known as specific gravity .

Back  -    New Search

relaxant (ri-laks-nt) n.

an agent that reduces tension and strain, particularly in muscles (see MUSCLE RELAXANT).

Back  -    New Search

relaxation (ree-laks-ay-shn) n.

(in physiology) the diminution of tension in a muscle, which occurs when it ceases to contract. r. therapy treatment by teaching a patient to decrease his anxiety by reducing the tone in his muscles.

Back  -    New Search

relaxin (ri-laks-in) n.

a hormone, secreted by the placenta in the terminal stages of pregnancy, that causes the cervix of the uterus to dilate and prepares the uterus for the action of oxytocin during labour.

Back  -    New Search

rem (rem) n.

a former unit dose of ionizing radiation; it was replaced by the sievert.

Back  -    New Search

REM n.

rapid eye movement: the stage of paradoxical sleep , during which the muscles of the eyeballs are in constant motion behind the eyelids. REM usually coincides with dreaming.

Back  -    New Search

remission (ri-mish-n) n.

1 a lessening in the severity of symptoms or their temporary disappearance during the course of an illness.

2 a reduction in the size of a cancer and the symptoms it is causing.
Top

Back  -    New Search

remittent fever (ri-mit-nt) n.

see FEVER.

Back  -    New Search

renal (ree-nl) adj.

relating to or affecting the kidneys. r. artery either of two large arteries arising from the abdominal aorta and supplying the kidneys. r. cell carcinoma see HYPERNEPHROMA. r. function tests tests for assessing the function of the kidneys, which include measurements of the specific gravity of urine, creatinine clearance time, and blood urea levels, as well as intravenous pyelography and renal angiography. r. tubule (uriniferous tubule ) the fine tubular part of a nephron, through which water and certain dissolved substances are reabsorbed back into the blood.

Back  -    New Search

reni- (reno-) prefix

denoting the kidney.

Back  -    New Search

renin (ree-nin) n.

an enzyme released into the blood by the kidney in response to stress. It produces angiotensin, which causes constriction of blood vessels and thus an increase in blood pressure. Excessive production of renin results in renal hypertension.

Back  -    New Search

rennin (ren-in) n.

an enzyme produced in the stomach that coagulates milk. It converts caseinogen (milk protein) into insoluble casein in the presence of calcium ions. This ensures that the milk remains in the stomach, exposed to protein-digesting enzymes, for as long as possible.

Back  -    New Search

renography (ri-nog-rfi) n.

the radiological study of the kidneys by a gamma camera following the intravenous injection of a radioactive substance, which is concentrated and excreted by the kidneys. The resultant graph of each kidney gives information regarding function and rate of drainage.

Back  -    New Search

reovirus (ree-oh-vy-rs) n.

one of a group of small RNA-containing viruses that infect both respiratory and intestinal tracts without producing specific or serious diseases (and were therefore termed respiratory enteric orphan viruses). Compare ECHOVIRUS.

Back  -    New Search

repetitive strain injury (RSI) (ri-pet-it-iv) n.

pain with associated loss of function in a limb resulting from its repeated movement or sustained static loading. Tenosynovitis and tendovaginitis of the wrist associated with typing or operating a word processor is the injury most frequently encountered.

Back  -    New Search

replantation (ree-plahn-tay-shn) n.

1 a developing specialty for the reattachment of severed limbs (or parts of limbs) and other body parts (e.g. the nose). It employs techniques of microsurgery to rejoin nerves and vessels.

2 (or reimplantation) (in dentistry) the reinsertion of a tooth into its socket after its accidental or deliberate removal.
Top

—replant vb.

Back  -    New Search

replication (rep-li-kay-shn) n.

the process by which DNA makes copies of itself when the cell divides. The two strands of the DNA molecule unwind and each strand directs the synthesis of a new strand complementary to itself.

Back  -    New Search

repolarization (ri-poh-ler-l-zay-shn) n.

the process in which the membrane of a nerve cell returns to its normal electrically charged state after a nerve impulse has passed.

Back  -    New Search

repositor (ri-poz-it-er) n.

an instrument used to return a displaced part of the body to its normal position.

Back  -    New Search

repression (ri-presh-n) n.

(in psychoanalysis) the process of excluding an unacceptable wish or an idea from conscious mental life. The repressed material may give rise to symptoms.

Back  -    New Search

reproductive system (ree-pr-duk-tiv) n.

the combination of organs and tissues associated with the process of reproduction. In males it includes the testes, vasa deferentia, prostate gland, seminal vesicles, urethra, and penis; in females it includes the ovaries, Fallopian tubes, uterus, vagina, and vulva.

Back  -    New Search

resection (ri-sek-shn) n.

surgical removal of a portion of any part of the body. submucous r. removal of part of the cartilage septum of the nose that has become deviated, usually by injury. transurethral r. of the prostate (TUR or TURP) an operation performed when the prostate gland becomes enlarged. It involves removal of portions of the gland through the urethra using an instrument called a resectoscope .

Back  -    New Search

resectoscope (ri-sek-t-skohp) n.

see (TRANSURETHRAL) RESECTION.

Back  -    New Search

reserpine (res-er-peen) n.

a drug extracted from rauwolfia. Administered by mouth or injection, it has been used to lower high blood pressure.

Back  -    New Search

residual urine (ri-zid-yoo-l) n.

urine remaining in the bladder after micturition.

Back  -    New Search

residual volume n.

the volume of air that remains in the lungs after the individual has breathed out as much as he can. This volume is increased in emphysema.

Back  -    New Search

resistance (ri-zist-ns) n.

1 the degree of immunity that the body possesses.

2 the degree to which a disease or disease causing organism remains unaffected by antibiotics or other drugs.
Top

Back  -    New Search

resolution (rez--loo-shn) n.

1 the stage during which inflammation gradually disappears.

2 the degree to which individual details can be distinguished by the eye, as through a microscope.
Top

Back  -    New Search

resonance (rez-n-ns) n.

the sound produced by percussion of a part of the body during a physical examination. See also VOCAL RESONANCE.

Back  -    New Search

resorcinol (ri-zor-sin-ol) n.

a drug that causes the skin to peel. It has been used in skin ointments to treat such conditions as acne.

Back  -    New Search

resorption (ri-sorp-shn) n.

loss of substance through physiological or pathological means.

Back  -    New Search

respiration (res-per-ay-shn) n.

the process of gaseous exchange between an organism and its environment. external r. breathing: the stage of respiration in which oxygen is taken up by the capillaries of the lung alveoli and carbon dioxide is released from the blood. internal r. the stage of respiration in which oxygen is released to the tissues and carbon dioxide absorbed by the blood. See also LUNG.
—respiratory (rs-pir--ter-i) adj.

Back  -    New Search

respirator (res-per-ayt-er) n.

1 a device used to maintain the breathing movements of paralysed patients. cuirass r. a type of respirator in which the patient is enclosed, except for the head and limbs, in an airtight container in which the air pressure is decreased and increased mechanically. This draws air into and out of the lungs, through the normal air passages. Drinker r. (iron lung ) a respirator that works on a similar principle to the cuirass respirator but also encloses the limbs. positive-pressure r. a respirator that blows air into the patient's lungs via a tube passed either through the mouth into the trachea or through a tracheostomy.

2 a face mask for administering oxygen or other gas or for filtering harmful fumes, dust, etc. See also ARTIFICIAL RESPIRATION.
Top

Back  -    New Search

respiratory distress syndrome (hyaline membrane disease) n.

the condition of a newborn infant in which the lungs are imperfectly expanded. Breathing is rapid, laboured, and shallow. The condition is most common and serious among preterm infants. It is treated by careful nursing, intravenous fluids, and oxygen, with or without positive pressure by a respirator. Recently, surfactant administered at birth has produced encouraging results.

Back  -    New Search

respiratory quotient (RQ) n.

the ratio of the volume of carbon dioxide transferred from the blood into the alveoli to the volume of oxygen absorbed into the alveoli. The RQ is usually about 0.8.

Back  -    New Search

respiratory syncytial virus (RSV) n.

a paramyxovirus (see MYXOVIRUS) that causes infections of the nose and throat. It is a major cause of bronchiolitis and pneumonia in young children.

Back  -    New Search

respiratory system n.

the combination of organs and tissues associated with breathing. It includes the nasal cavity, pharynx, larynx, trachea, bronchi, and lungs.

Back  -    New Search

response (ri-spons) n.

the way in which the body or part of the body reacts to a stimulus.

Back  -    New Search

responsibility (ri-spons-i-bil-iti) n.

(in nursing) the state of being answerable for one's performance according to the terms of reference of the Code of Professional Conduct (see Code of Professional Conduct for Nurses, Midwives, and Health Care Workers). It involves demonstrating commitment and trustworthiness during the performance of care through devolved authority. Nurses (whether registered or not) are responsible for their actions at all times.

Back  -    New Search

restenosis (ree-sti-noh-sis) n.

recurrent stenosis, especially in a heart valve or an artery after corrective surgery.

Back  -    New Search

rest pain (rest) n.

pain, usually experienced in the feet, that indicates an extreme degree of ischaemia.

Back  -    New Search

resuscitation (ri-sus-i-tay-shn) n.

the process of reviving someone who appears to be dead; for example by cardiac massage or artificial respiration.

Back  -    New Search

retardation (ree-tar-day-shn) n.

the slowing up of a process. psychomotor r. a marked slowing down of activity and speech. It is a symptom of severe depression. See also MENTAL RETARDATION.

Back  -    New Search

retching (rech-ing) n.

repeated unavailing attempts to vomit.

Back  -    New Search

rete (ree-ti) n.

a network of blood vessels, nerve fibres, or other strands of interlacing tissue in the structure of an organ.

Back  -    New Search

retention (ri-ten-shn) n.

inability to pass urine, which is retained in the bladder. The condition may be acute and painful or chronic and painless. The commonest cause is enlargement of the prostate gland in men.

Back  -    New Search

retention cyst n.

a cyst that arises when the outlet of the duct of a gland is blocked.

Back  -    New Search

retention defect n.

(in psychology) a memory defect in which items that have been registered in the memory are lost from storage. It is a feature of dementia.

Back  -    New Search

reticular (ri-tik-yoo-ler) adj.

(of tissues) resembling a network; branching. r. fibres branching fibres of connective tissue that form a delicate supportive meshwork around blood vessels, muscle fibres, glands, nerves, etc. r. formation a network of nerve pathways and nuclei throughout the brainstem, connecting motor and sensory nerves to and from the spinal cord, the cerebellum and the cerebrum, and the cranial nerves.

Back  -    New Search

reticulin (ri-tik-yoo-lin) n.

the collagen-like protein of reticular fibres.

Back  -    New Search

reticulocyte (ri-tik-yoo-loh-syt) n.

an immature red blood cell (erythrocyte). Reticulocytes normally comprise about 1% of the total red cells.

Back  -    New Search

reticulocytosis (ri-tik-yoo-loh-sy-toh-sis) n.

an increase in the proportion of reticulocytes in the bloodstream: a sign of increased output of new red cells from the bone marrow.

Back  -    New Search

reticuloendothelial system (RES) (ri-tik-yoo-loh-en-doh-theel-il) n.

a community of phagocytes that is spread throughout the body. The RES is concerned with defence against microbial infection and with the removal of wornout blood cells from the bloodstream. See also SPLEEN.

Back  -    New Search

reticuloendotheliosis (histiocytosis X) (ri-tik-yoo-loh-en-doh-theel-i-oh-sis) n.

overgrowth of cells of the reticuloendothelial system, causing either isolated swelling of the bone marrow (eosinophilic granuloma ) or destruction of the bones of the skull (Hand-Schüller-Christian disease ). The most acute form is associated with tumours containing histiocytes in the internal organs (Letterer-Siwe disease ).

Back  -    New Search

reticulosis (ri-tik-yoo-loh-sis) n.

abnormal overgrowth, usually malignant, of any of the cells of the lymphatic glands or the immune system. See BURKITT'S LYMPHOMA, HODGKIN'S DISEASE, LYMPHOMA, MYCOSIS FUNGOIDES.

Back  -    New Search

reticulum (ri-tik-yoo-lm) n.

a network of tubules or blood vessels. See ENDOPLASMIC RETICULUM.

Back  -    New Search

retin- (retino-) prefix

denoting the retina.

Back  -    New Search

retina (ret-in-) n.

the light-sensitive layer that lines the interior of the eye. The inner part of the retina, next to the cavity of the eyeball, contains rods and cones (light-sensitive cells) and their associated nerve fibres. The outer part (retinal pigment epithelium; RPE ) is pigmented to prevent the passage of light.
—retinal adj.

Back  -    New Search

retinaculum (ret-in-ak-yoo-lm) n. (pl. retinacula)

a thickened band of tissue that serves to hold various tissues in place.

Back  -    New Search

retinal (retinene) (ret-in-al) n.

the aldehyde of retinol (vitamin A). See also RHODOPSIN.

Back  -    New Search

retinal artery occlusion (ret-in-l) n.

blockage of an artery supplying blood to the retina, usually as a result of thrombosis or embolism. branch r. a. o. blockage of one of the branches of the central retinal artery, usually by emboli, which results in ischaemia of the retina supplied by the occluded vessel and related visual field loss. central r. a. o. blockage of the central retinal artery, which enters the eye at the optic disc and then divides into branches to supply different parts of the retina, usually resulting in sudden painless loss of vision.

Back  -    New Search

retinal detachment (detached retina) n.

separation of the inner nervous layer of the retina from the outer pigmented layer (retinal pigment epithelium), causing loss of vision in the affected part of the retina. The condition can be treated surgically by creating patches of scar tissue between the retina and the choroid (see CRYOSURGERY, PHOTOCO-AGULATION); this, combined with plombage, allows reattachment of the retina.

Back  -    New Search

retinal vein occlusion n.

blockage of a vein carrying blood from the retina. branch r. v. o. blockage of one of the small branch veins, which carry blood from different parts of the retina and drain into the central retinal vein, resulting in painless reduction of vision in the affected area. central r. v. o. blockage of the central retinal vein, which leaves the eye at the optic disc, usually resulting in sudden painless reduction of vision.

Back  -    New Search

retinene (ret-in-een) n.

see RETINAL.

Back  -    New Search

retinitis (ret-i-ny-tis) n.

inflammation of the retina. r. pigmentosa a noninflammatory hereditary condition that is characterized by progressive degeneration of the retina due to malfunctioning of the retinal pigment epithelium. Night blindness and limited peripheral vision starting in childhood may progress to complete loss of vision.

Back  -    New Search

retinoblastoma (ret-in-oh-blas-toh-m) n.

a rare malignant tumour of the retina, occurring in infants.

Back  -    New Search

retinoid (ret-in-oid) n.

one of a group of drugs derived from vitamin A that act on the skin to cause drying and peeling and a reduction in oil (sebum) production. Retinoids include isotretinoin and tretinoin; they are used in the treatment of severe acne, psoriasis, ichthyosis, and other skin disorders. Possible side-effects, which may be serious, include severe fetal abnormalities (if taken by pregnant women), toxic effects on babies (if taken by breast-feeding mothers), and liver and kidney damage.

Back  -    New Search

retinol (ret-in-ol) n.

see VITAMIN A.

Back  -    New Search

retinopathy (ret-in-op--thi) n.

any of various disorders of the retina resulting in impairment or loss of vision. AIDS r. retinopathy that occurs as a complication of AIDS. diabetic r. retinopathy resulting from diabetes, in which haemorrhaging or exudation may occur, either from damaged vessels into the retina or from new abnormal vessels into the vitreous humour (see NEOVASCULARIZATION).

Back  -    New Search

retinoscope (ret-in-oh-skohp) n.

an instrument used to determine the power of spectacle lenses required to correct errors of refraction of the eye.
—retinoscopy (ret-in-os-k-pi) n.

Back  -    New Search

retraction (ri-trak-shn) n.

1 (in obstetrics) the quality of uterine muscle fibres of remaining shortened after contracting during labour. This results in a gradual progression of the fetus downward through the pelvis. r. ring a depression in the uterine wall marking the junction between the actively contracting muscle fibres of the upper segment and the muscle fibres of the lower segment of the uterus. This depression is not always visible and is normal. Compare BANDL'S RING.

2 (in dentistry) the drawing back of one or more teeth into a better position by an orthodontic appliance.
Top

Back  -    New Search

retractor (ri-trak-ter) n.

a surgical instrument used to expose the operation site by drawing aside the cut edges of skin, muscle, or other tissues. See illustration.

Back  -    New Search

retro- prefix

denoting at the back or behind.

Back  -    New Search

retrobulbar neuritis (optic neuritis) (ret-roh-bulb-er) n.

inflammation of the optic nerve behind the eye, causing increasingly blurred vision. Retrobulbar neuritis is one of the symptoms of multiple sclerosis but it can also occur as an isolated lesion.

Back  -    New Search

retroflexion (ret-roh-flek-shn) n.

the bending backward of an organ or part of an organ, especially the abnormal bending backwards of the upper part of the uterus.

Back  -    New Search

retrograde (ret-roh-grayd) adj.

going backwards, or moving in the opposite direction to the normal. See also (RETROGRADE) AMNESIA, (RETROGRADE) PYELOGRAPHY.

Back  -    New Search

retrogression (ret-roh-gresh-n) n.

return to a less complex state or condition; regression.

Back  -    New Search

retrolental fibroplasia (ret-roh-len-t'l) n.

the abnormal proliferation of fibrous tissue immediately behind the lens of the eye, leading to blindness. It is most commonly seen in newborn preterm infants, in whom it is associated with high concentrations of inhaled oxygen.

Back  -    New Search

retro-ocular (ret-roh-ok-yoo-ler) adj.

behind the eye.

Back  -    New Search

retroperitoneal fibrosis (RPF) (ret-roh-pe-ri-tn-ee-l) n.

a condition in which a dense plaque of fibrous tissue develops behind the peritoneum adjacent to the abdominal aorta. The ureters become encased and hence obstructed, causing acute anuria and renal failure. The obstruction can be relieved by nephrostomy or the insertion of double J stents. In the acute phase steroid administration may help, but in established RPF ureterolysis is required.

Back  -    New Search

retroperitoneal space n.

the region between the posterior parietal peritoneum and the front of the lumbar vertebrae. This space contains important structures, including the kidneys, adrenal glands, pancreas, lumbar spinal nerve roots, sympathetic ganglia and nerves, and the abdominal aorta and its major branches.

Back  -    New Search

retropharyngeal (ret-roh-f-rin-ji-l) adj.

behind the pharynx. r. abscess a collection of pus in the tissues behind the pharynx, resulting in difficulty in swallowing, pain, and fever.

Back  -    New Search

retropubic (ret-roh-pew-bik) adj.

behind the pubis. r. prostatectomy see PROSTATECTOMY.

Back  -    New Search

retropulsion (ret-roh-pul-shn) n.

a compulsive tendency to walk backwards. It is a symptom of parkinsonism.

Back  -    New Search

retrospection (ret-roh-spek-shn) n.

(in psychology) the systematic reviewing of past experiences.

Back  -    New Search

retroversion (ret-roh-ver-shn) n.

an abnormal position of the uterus in which it is tilted backwards, with the base lying in the pouch of Douglas, against the rectum, instead of on the bladder.

Back  -    New Search

retrovirus (ret-roh-vy-rs) n.

an RNA-containing virus that can convert its genetic material into DNA, which enables it to become integrated into the DNA of its host's cells. Retroviruses include HIV and viruses implicated in the development of some cancers.

Back  -    New Search

Rett's syndrome (rets) n.

a disorder affecting young girls, in which stereotyped movements and social withdrawal appear during early childhood. Intellectual development is often impaired and special educational help is needed. [A. Rett (20th century), Austrian paediatrician]

Back  -    New Search

revascularization (ri-vas-kew-ler-l-zay-shn) n.

1 the regrowth of blood vessels following disease or injury so that normal blood supply to an organ, tissue, or part is restored.

2 the surgical operation of re-establishing the blood supply to a tissue or organ by means of a blood-vessel graft. coronary r. re-establishing blood flow through the coronary arteries, usually by means of a coronary bypass graft.
Top

Back  -    New Search

Reye's syndrome (rayz) n.

a rare disorder occurring in childhood. It is characterized by the symptoms of encephalitis combined with evidence of liver failure. Treatment is aimed at controlling cerebral oedema and correcting metabolic abnormalities, but there is a significant mortality and there may be residual brain damage. The cause is not known, but aspirin has been implicated and this drug should not be used in children below the age of 12 unless specifically indicated. [R. D. K. Reye (1912–77), Australian histopathologist]

Back  -    New Search

RGN n.

registered general nurse: see NURSE.

Back  -    New Search

rhabdomyosarcoma (rab-doh-my-oh-sar-koh-m) n.

a rare malignant tumour originating in, or showing the characteristics of, striated muscle. embryonal r. a type of rhabdomyosarcoma that affects infants, children, and young adults. pleomorphic r. a type of rhabdomyosarcoma that occurs in late middle age, in the muscles of the limbs.

Back  -    New Search

rhagades (rag--deez) pl. n.

cracks or long thin scars in the skin, particularly around the mouth. The fissures around the mouth and nose of babies with congenital syphilis eventually heal to form rhagades.

Back  -    New Search

rheo- prefix

denoting 1 a flow of liquid.

2 an electric current.
Top

Back  -    New Search

rhesus factor (Rh factor) (ree-ss) n.

a group of antigens that may or may not be present on the surface of the red blood cells; it forms the basis of the rhesus blood group system. Most people have the rhesus factor, i.e. they are Rh-positive . People who lack the factor are termed Rh-negative . Incompatibility between Rh-positive and Rh-negative blood is an important cause of blood transfusion reactions and of haemolytic disease of the newborn. See also BLOOD GROUP.

Back  -    New Search

rheumatic fever (acute rheumatism) (roo-mat-ik) n.

a disease affecting mainly children and young adults that arises as a delayed complication of infection of the upper respiratory tract with haemolytic streptococci. The main features are fever, arthritis, Sydenham's chorea, and inflammation of the heart muscle, its valves, and the membrane surrounding the heart. The infection is treated with antibiotics (e.g. penicillin) and bed rest. chronic rheumatic heart disease a complication of rheumatic fever, in which there is scarring and chronic inflammation of the heart and its valves leading to heart failure, murmurs, and damage to the valves.

Back  -    New Search

rheumatism (room--tizm) n.

any disorder in which aches and pains affect the muscles and joints. See RHEUMATOID ARTHRITIS, RHEUMATIC FEVER, OSTEOARTHRITIS, GOUT.

Back  -    New Search

rheumatoid arthritis (room--toid) n.

a form of arthritis that is a disease of the synovial lining of joints. It involves the joints of the fingers, wrists, feet, and ankles, with later involvement of the hips, knees, shoulders, and neck. Diagnosis is supported by a blood test and by X-rays revealing typical changes around the affected joints. Treatment is with a variety of drugs, including anti-inflammatory analgesics, steroids, methotrexate, and gold injections, and some diseased joints can be replaced by prosthetic surgery (see ARTHROPLASTY).

Back  -    New Search

rheumatology (room--tol-ji) n.

the medical specialty concerned with the diagnosis and management of disease involving joints, tendons, muscles, ligaments, and associated structures. See also PHYSICAL MEDICINE.
—rheumatologist n.

Back  -    New Search

Rh factor n.

see RHESUS FACTOR.

Back  -    New Search

rhin- (rhino-) prefix

denoting the nose.

Back  -    New Search

rhinitis (ry-ny-tis) n.

inflammation of the mucous membrane of the nose. acute r. see (COMMON) COLD. allergic r. see HAY FEVER. atrophic r. rhinitis in which the mucous membrane becomes thinned and fragile. perennial r. (vasomotor r.) rhinitis in which there is overgrowth of, and increased secretion by, the membrane.

Back  -    New Search

rhinology (ry-nol-ji) n.

the branch of medicine concerned with disorders of the nose and nasal passages.

Back  -    New Search

rhinomycosis (ry-noh-my-koh-sis) n.

fungal infection of the lining of the nose.

Back  -    New Search

rhinophyma (ry-noh-fy-m) n.

a bulbous craggy swelling of the nose, usually in men. It is a complication of rosacea and in no way related to alcohol intake.

Back  -    New Search

rhinoplasty (ry-noh-plasti) n.

surgery to alter the shape of the nose.

Back  -    New Search

rhinorrhoea (ry-n-ree-) n.

a persistent watery mucous discharge from the nose, as in the common cold.

Back  -    New Search

rhinoscopy (ry-nosk--pi) n.

examination of the interior of the nose.

Back  -    New Search

rhinosinusitis (ry-noh-sy-ns-l-tis) n.

inflammation of the lining of the nose and paranasal sinuses, caused by allergies, infection, immune deficiencies, mucociliary transport abnormalities, trauma, drugs, or tumours. See RHINITIS, SINUSITIS.

Back  -    New Search

rhinosporidiosis (ry-noh-sper-id-i-oh-sis) n.

a fungal infection of the mucous membranes of the nose, larynx, eyes, and genitals that is characterized by the formation of polyps.

Back  -    New Search

rhinovirus (ry-noh-vy-rs) n.

any one of a group of RNA-containing viruses that cause respiratory infections in man resembling the common cold. They are included in the picornavirus group.

Back  -    New Search

rhiz- (rhizo-) prefix

denoting a root.

Back  -    New Search

rhizotomy (ry-zot-mi) n.

a surgical procedure in which selected nerve roots are cut at the point where they emerge from the spinal cord. The posterior (sensory) nerve roots are cut for the relief of intractable pain; the anterior (motor) nerve roots are sometimes cut for the relief of severe muscle spasm.

Back  -    New Search

rhodopsin (visual purple) (roh-dop-sin) n.

a pigment in the retina of the eye consisting of retinal and a protein. The presence of rhodopsin is essential for vision in dim light. See ROD.

Back  -    New Search

rhombencephalon (rom-ben-sef--lon) n.

see HINDBRAIN.

Back  -    New Search

rhomboid (rom-boid) n.

either of two muscles situated in the upper part of the back, between the backbone and shoulder blade. They help to move the shoulder blade backwards and upwards.

Back  -    New Search

rhonchus (ronk-s) n. (pl. rhonchi)

an abnormal musical noise produced by air passing through narrowed bronchi. It is heard through a stethoscope, usually when the patient breathes out.

Back  -    New Search

rhythm method (rith-m) n.

a contraceptive method in which sexual intercourse is restricted to the days at the beginning and end of the menstrual cycle when conception is least likely to occur (safe period ). The method depends for its reliability on the woman having uniform regular periods and its failure rate is higher than with mechanical methods.

Back  -    New Search

rib (rib) n.

a curved strip of bone forming part of the skeleton of the thorax. There are 12 pairs of ribs. The head of each rib articulates with one of the 12 thoracic vertebrae of the backbone; the other end is attached to a costal cartilage. false r. any of the three pairs of ribs below the true ribs. Each is connected by its cartilage to the rib above it. floating r. any of the last two pairs of ribs, which end freely in the muscles of the body wall. true r. any of the first seven pairs of ribs, which are connected directly to the sternum by their costal cartilages. Anatomical name: costa .

Back  -    New Search

ribavirin (ry-b-vy-rin) n.

an antiviral drug effective against a range of DNA and RNA viruses, including the herpes group, respiratory syncytial virus, and those causing hepatitis, several strains of influenza, and Lassa fever. It is administered by a small-particle aerosol inhaler and sometimes by intravenous injection. Trade name: Virazole .

Back  -    New Search

riboflavin (vitamin B_2) (ry-boh-flay-vin) n.

see VITAMIN B.

Back  -    New Search

ribonuclease (ry-boh-new-kli-ayz) n.

an enzyme, located in the lysosomes of cells, that splits RNA at specific places in the molecule.

Back  -    New Search

ribonucleic acid (ry-boh-new-klee-ik) n.

see RNA.

Back  -    New Search

ribose (ry-bohz) n.

a pentose sugar that is a component of RNA and several coenzymes. Ribose is also involved in intracellular metabolism.

Back  -    New Search

ribosome (ry-b-sohm) n.

a particle, consisting of RNA and protein, that occurs in cells and is the site of protein synthesis in the cell (see TRANSLATION).
—ribosomal adj.

Back  -    New Search

ricewater stools (rys-waw-ter) pl. n.

see CHOLERA.

Back  -    New Search

ricin (ry-sin) n.

a highly toxic albumin obtained from castor-oil seeds (Ricinus communis) that inhibits protein synthesis and becomes attached to the surface of cells, resulting in gastroenteritis, hepatic congestion and jaundice, and cardiovascular collapse. See also IMMUNOTOXIN.

Back  -    New Search

rickets (rik-its) n.

a disease of childhood in which the bones do not harden due to a deficiency of vitamin D. See also OSTEOMALACIA. renal r. a type of rickets that is due to impaired kidney function causing boneforming minerals to be excreted in the urine, which results in softening of the bones.

Back  -    New Search

rickettsiae (ri-ket-si-ee) pl. n. (sing. rickettsia)

a group of very small nonmotile spherical or rodlike parasitic organisms. They cause such illnesses as rickettsial pox, Rocky Mountain spotted fever, and typhus. Rickettsiae infect arthropods (ticks, mites, etc.), through whom they can be transmitted to mammals (including man).
—rickettsial (ri-ket-si-l) adj.

Back  -    New Search

rickettsial pox n.

a disease of mice caused by the microorganism Rickettsia akari and transmitted to man by mites: it produces chills, fever, muscular pain, and a rash similar to that of chickenpox. See also TYPHUS.

Back  -    New Search

ridge (rij) n.

1 (in anatomy) a crest or a long narrow protuberance, e.g. on a bone.

2 (in dental anatomy) see ALVEOLUS.
Top

Back  -    New Search

rifampicin (rif-am-pi-sin) n.

an antibiotic administered by mouth to treat various infections, particularly tuberculosis. Trade names: Rifadin , Rimactane .

Back  -    New Search

rigidity (ri-jid-iti) n.

(in neurology) resistance to the passive movement of a limb that persists throughout its range. It is a symptom of parkinsonism. Compare SPASTICITY.

Back  -    New Search

rigor (ry-ger) n.

an abrupt attack of shivering and a sensation of coldness, accompanied by a rapid rise in body temperature. This often marks the onset of a fever and may be followed by a feeling of heat, with copious sweating. r. mortis the stiffening of a body that occurs within some eight hours of death, due to chemical changes in muscle tissue. It starts to disappear after about 24 hours.

Back  -    New Search

rima (ry-m) n.

(in anatomy) a cleft. r. glottidis the space between the vocal folds.

Back  -    New Search

rimiterol (rim-i-te-rol) n.

a drug, similar to isoprenaline, administered by inhalation as a bronchodilator to relieve asthma and chronic bronchitis. Trade name: Pulmadil .

Back  -    New Search

ring (ring) n.

(in anatomy) see ANNULUS.

Back  -    New Search

ring block n.

a circumferential ring of local anaesthetic solution used to block the nerves of a digit for purposes of minor surgery (see NERVE BLOCK). Precautions are necessary to avoid vascular damage leading to gangrene.

Back  -    New Search

Ringer's solution (Ringer's mixture) (ring-erz) n.

a clear colourless physiological solution of sodium chloride, potassium chloride, and calcium chloride prepared with recently boiled pure water. [S. Ringer (1835–1910), British physiologist]

Back  -    New Search

ringworm (ring-werm) n.

see TINEA.

Back  -    New Search

Rinne's test (rin-iz) n.

a test to determine whether deafness is conductive or sensorineural. A vibrating tuning fork is held first in the air, close to the ear, and then with its base placed on the mastoid process. If the sound conducted by air is heard louder than the sound conducted by bone the test is positive and the deafness sensorineural; a negative result indicates conductive deafness. [H. A. Rinne (1819–68), German otologist]

Back  -    New Search

risk factor (risk) n.

an attribute, such as a habit (e.g. cigarette smoking) or exposure to some environmental hazard, that leads the individual concerned to have a greater likelihood of developing an illness. The relationship is one of probability and as such can be distinguished from a causal agent.

Back  -    New Search

risperidone (ris-pe-ri-dohn) n.

an atypical antipsychotic drug used in the treatment of schizophrenia and other psychoses in patients unresponsive to conventional antipsychotics. Side-effects are fewer and less severe than those of conventional antipsychotics. Trade name: Risperdal .

Back  -    New Search

risus sardonicus (ry-ss sar-don-ik-s) n.

an abnormal grinning expression resulting from involuntary prolonged contraction of facial muscles, as seen in tetanus.

Back  -    New Search

Ritter's disease (rit-erz) n.

see STAPHYLOCOCCAL SCALDED SKIN SYNDROME. [G. Ritter von Rittershain (1820–83), German physician]

Back  -    New Search

river blindness n.

see ONCHOCERCIASIS.

Back  -    New Search

RMI n.

(in the UK) Resource Management Initiative: a scheme set up by the DHSS in 1986, following the publication of the Griffiths report into NHS management (1983), to design and implement management budgeting in the NHS. The RMI has established resource management experiments in six acute hospital sites in England that are sponsored and monitored by the NHS Management Board, the Joint Consultants Committee, and local management.

Back  -    New Search

RMN n.

registered mental nurse: see NURSE.

Back  -    New Search

RN n.

registered nurse: see NURSE.

Back  -    New Search

RNA (ribonucleic acid) n.

a nucleic acid, occurring in the nucleus and cytoplasm of cells, that is concerned with synthesis of proteins (see MESSENGER RNA, RIBOSOME, TRANSFER RNA, TRANSLATION). In some viruses RNA is the genetic material.

Back  -    New Search

RNMH n.

registered nurse for the mentally handicapped: see NURSE.

Back  -    New Search

Rocky Mountain spotted fever (spotted fever, tick fever) n.

a disease of rodents and other small mammals in the USA caused by the microorganism Rickettsia rickettsii and transmitted to man by ticks. Symptoms include fever, muscle pains, and a profuse reddish rash like that of measles. Treatment with tetracycline or chloramphenicol is effective. See also TYPHUS.

Back  -    New Search

rod (rod) n.

one of the two types of light-sensitive cells in the retina of the eye (compare CONE). Rods are necessary for seeing in dim light. They contain the pigment rhodopsin, which is bleached in the light and regenerated in the dark. When all the pigment is bleached (i.e. in bright light) the rods no longer function. See also DARK ADAPTATION, LIGHT ADAPTATION.

Back  -    New Search

rodent ulcer (roh-dnt) n.

see BASAL CELL CARCINOMA.

Back  -    New Search

roentgen (ront-gn) n.

a unit of exposure dose of X- or gamma-radiation.

Back  -    New Search

role playing (rohl-play-ing) n.

acting out another person's expected behaviour, usually in a contrived situation, in order to understand that person better. It is used in family psychotherapy, in teaching social skills to patients, and also in the training of psychiatric (and other) staff.

Back  -    New Search

Romanowsky stains (roh-m-nof-ski) pl. n.

a group of stains used for microscopical examination of blood cells, consisting of variable mixtures of thiazine dyes with eosin. [D. L. Romanowsky (1861–1921), Russian physician]

Back  -    New Search

Romberg's sign (rom-bergz) n.

a finding on examination suggesting either a sensory disorder affecting those nerves that transmit information to the brain about the position of the limbs and joints and the tension in the muscles or a failure of the cerebellum to process this information. The patient is unable to maintain an upright posture when his eyes are closed. [M. Romberg (1795–1873), German neurologist]

Back  -    New Search

rongeur (rawn-zher) n.

powerful biting forceps for cutting tissue, particularly bone.

Back  -    New Search

root (root) n.

1 (in neurology) a bundle of nerve fibres at its emergence from the spinal cord.

2 (in dentistry) the part of a tooth that is not covered by enamel and is normally attached to the alveolar bone by periodontal fibres. r. canal treatment the procedure of removing the remnants of the pulp of a tooth, cleaning and shaping the canal inside the tooth, and filling the root canal.
Top

3 the origin of any structure, i.e. the point at which it diverges from another structure. Anatomical name: radix .
Top

Back  -    New Search

rooting reflex (root-ing) n.

a primitive reflex present in newborn babies: if the cheek is stroked near the mouth, the infant will turn its head to the same side to suckle.

Back  -    New Search

Roper, Logan, and Tierney model (roh-per loh-gn teer-ni) n.

a model for nursing that emphasizes the importance of the patient's ability to perform activities of living (see ACTIVITIES OF DAILY LIVING). Individuals are seen as being engaged in various activities of living throughout their lifespan; during their lives they will fluctuate between total independence and total dependence, according to age, circumstance, and health status. Nursing should provide assistance with these activities when needed. See also NURSING MODELS. [N. Roper , W. Logan , and A. Tierney (20th century), British nurse theorists]

Back  -    New Search

Rorschach test (ror-shahk) n.

a test to measure aspects of personality, consisting of ten inkblots in colour and black and white. The responses to the different inkblots are used to derive hypotheses about the subject. [H. Rorschach (1884–1922), Swiss psychiatrist]

Back  -    New Search

rosacea (roh-zay-shi) n.

a chronic inflammatory disease of the face in which the skin becomes abnormally flushed. The disease occurs in both sexes and at all ages but is most common in women in their thirties.

Back  -    New Search

roseola (roseola infantum) (roh-zee--l) n.

a condition of young children in which a fever lasting for three or four days is followed by a rose-coloured rash that fades after two days. It is caused by human herpesvirus 6.

Back  -    New Search

rostrum (ros-trm) n. (pl. rostra)

(in anatomy) a beaklike projection, such as that on the sphenoid bone.
—rostral adj.

Back  -    New Search

rotator (roh-tay-ter) n.

muscle that brings about rotation of a part.

Back  -    New Search

Rothera's test (roth-er-z) n.

a method of testing urine for the presence of acetone or acetoacetic acid - a sign of diabetes mellitus. [A. C. H. Rothera (1880–1915), Australian biochemist]

Back  -    New Search

Roth spot (roht) n.

pale area surrounded by haemorrhage sometimes seen in the retina of those who have bacterial endocarditis, septicaemia, or leukaemia. [M. Roth (1839–1915), Swiss physician]

Back  -    New Search

roughage (ruf-ij) n.

see DIETARY FIBRE.

Back  -    New Search

rouleau (roo-loh) n. (pl. rouleaux)

a cylindrical structure in the blood formed from several red blood cells piled one upon the other and adhering by their rims.

Back  -    New Search

round ligaments (rownd) pl. n.

the fibro-muscular bands that pass from the uterus along the broad ligaments to terminate in the labia majora.

Back  -    New Search

round window n.

see FENESTRA (ROTUNDA).

Back  -    New Search

roundworm (rownd-werm) n.

see NEMATODE.

Back  -    New Search

Rovsing's sign (rov-singz) n.

pain in the right iliac fossa induced by pressure on the left iliac fossa: a sign of acute appendicitis. [N. T. Rovsing 1868–1927), Danish surgeon]

Back  -    New Search

Roy's model (roiz) n.

model for nursing based on the assumption that individuals are constantly adapting to changes in their environment. Adaptive responses to environmental stimuli are by means of innate or acquired mechanisms and work within the modes of physiological function, the concept of ‘self’, role function, and interdependence. Nursing should aim to promote and support these adaptive responses. See also NURSING MODELS. [C. Roy (1939– ), US nurse theorist]

Back  -    New Search

RPE n.

retinal pigment epithelium. See RETINA.

Back  -    New Search

-rrhagia (-rrhage) suffix

denoting excessive or abnormal flow or discharge from an organ or part.

Back  -    New Search

-rrhaphy suffix

denoting surgical sewing; suturing.

Back  -    New Search

-rrhexis suffix

denoting splitting or rupture of a part.

Back  -    New Search

-rrhoea suffix

denoting a flow or discharge from an organ or part.

Back  -    New Search

RSCN n.

registered sick children's nurse: see NURSE.

Back  -    New Search

RSI n.

see REPETITIVE STRAIN INJURY.

Back  -    New Search

RSV n.

see RESPIRATORY SYNCYTIAL VIRUS.

Back  -    New Search

rubefacient (roo-bi-fay-shnt) n.

an agent that causes reddening and warming of the skin. Rubefacients are often used as counterirritants for the relief of muscular pain.

Back  -    New Search

rubella (roo-bel-) n.

see GERMAN MEASLES.

Back  -    New Search

rubeola (roo-bee--l) n.

see MEASLES.

Back  -    New Search

rubor (roo-ber) n.

redness: one of the four classical signs of inflammation in a tissue. See also CALOR, DOLOR, TUMOR.

Back  -    New Search

ruga (roo-g) n. (pl. rugae)

a fold or crease, especially one of the folds of mucous membrane that line the stomach.

Back  -    New Search

rumination (roo-mi-nay-shn) n.

(in psychiatry) an obsessional type of thinking in which the same thoughts or themes are experienced repetitively. The thoughts are irrational and resisted by the patient.

Back  -    New Search

rupia (roo-pi) n.

dark raised crusts on the skin, as occurs in secondary syphilis.

Back  -    New Search

rupture (rup-cher)

1 n. see HERNIA.

2 n. the bursting apart or open of an organ or tissue; for example, the splitting of the membranes enclosing an infant during childbirth.
Top

3 vb. (of tissues, etc.) to burst apart or open.
Top

Back  -    New Search

Russell-Silver syndrome (rus-l sil-ver) n.

a congenital condition characterized by short stature, a triangular face with a small mandible (lower jaw), and asymmetry of the body. [W. Russell (1852–1940), British pathologist; H. K. Silver (1918– ), US paediatrician]

Back  -    New Search

Russell traction n.

a form of traction used to align a fractured femur. The lower leg is supported in a sling just below the knee and pulling forces are exerted upwards and longitudinally by means of pulleys and weights. [R. H. Russell (1860–1933), Australian surgeon]

Back  -    New Search

Ryle's tube (rylz) n.

a thin flexible tube of rubber or plastic, which is inserted into the stomach through the mouth or nose of a patient and is used for withdrawing fluid from the stomach or for giving a test meal. [J. A. Ryle (1889–1950), British physician]

Back  -    New Search

S

Sabin vaccine (say-bin) n.

an oral vaccine against poliomyelitis. [A. B. Sabin 1906–93), US bacteriologist]

Back  -    New Search

sac (sak) n.

a pouch or baglike structure. Sacs can enclose natural cavities in the body, e.g. in the lungs (see ALVEOLUS), or they can be pathological, as in a hernia.

Back  -    New Search

saccades (sa-kah-deez) pl. n.

voluntary rapid movements of the eyes, usually when changing the point of fixation on an object (e.g. when reading).

Back  -    New Search

sacchar- (saccharo-) prefix

denoting sugar.

Back  -    New Search

saccharide (sak-eryd) n.

a carbohydrate. See also DISACCHARIDE, MONOSACCHARIDE, POLYSACCHARIDE.

Back  -    New Search

saccharine (sak-er-een) n.

a sweetening agent. Saccharine is 400 times as sweet as sugar and has no energy content. It is very useful as a sweetener in diabetic and low-calorie foods.

Back  -    New Search

Saccharomyces (sak-er-oh-my-seez) n.

see YEAST.

Back  -    New Search

sacculated (sak-yoo-layt-id) adj.

pursed out with small pouches or sacs.

Back  -    New Search

saccule (sacculus) (sak-yool) n.

the smaller of the two membranous sacs within the vestibule of the ear. It contains a macula, which responds to gravity and relays information to the brain about the position of the head.

Back  -    New Search

sacralization (say-kr-ly-zay-shn) n.

abnormal fusion of the fifth lumbar vertebra with the sacrum.

Back  -    New Search

sacral nerves (say-krl) pl. n.

the five pairs of spinal nerves that emerge from the spinal column in the sacrum. The nerves carry sensory and motor fibres from the upper and lower leg and from the anal and genital regions.

Back  -    New Search

sacral vertebrae pl. n.

see SACRUM.

Back  -    New Search

sacro- prefix

denoting the sacrum.

Back  -    New Search

sacrococcygeal (say-kroh-kok-sij-il) adj.

relating to or between the sacrum and the coccyx.

Back  -    New Search

sacroiliac (say-kroh-il-i-ak) adj.

relating to the sacrum and the ilium.

Back  -    New Search

sacroiliitis (say-kroh-il-i-l-tis) n.

inflammation of the sacroiliac joint. Involvement of both joints is a common feature of ankylosing spondylitis and associated rheumatic diseases. The resultant low back pain and stiffness may be alleviated by rest and by the use of anti-inflammatory analgesics.

Back  -    New Search

sacrum (say-krm) n. (pl. sacra)

a curved triangular element of the backbone consisting of five fused vertebrae (sacral vertebrae ). It articulates with the last lumbar vertebra above, the coccyx below, and the hip bones laterally. See also VERTEBRA.
—sacral adj.

Back  -    New Search

saddle-nose (sa-d'l-nohz) n.

flattening of the bridge of the nose, such as may occur in congenital syphilis.

Back  -    New Search

sadism (say-dizm) n.

sexual excitement in response to inflicting pain upon other people. See also MASOCHISM, SEXUAL DEVIATION.
—sadist n. —sadistic (s-dis-tik) adj.

Back  -    New Search

SADS (seasonal affective disorder syndrome) (sadz) n.

a disorder in which the mood of the affected person is said to change according to the season of the year. Typically, with the onset of winter, there is depression, general slowing of mind and body, excessive sleeping, and overeating. These symptoms resolve with the coming of spring. SADS is not yet generally accepted as a clinical entity, although there is evidence that mood is related to light, which suppresses the release of the hormone melatonin from the pineal gland.

Back  -    New Search

safe period (sayf) n.

see RHYTHM METHOD.

Back  -    New Search

sagittal (saj-it'l) adj.

describing the dorsoventral plane that extends down the long axis of the body, dividing it into right and left halves. s. suture the immovable joint between the two parietal bones of the skull.

Back  -    New Search

salaam attacks (s-lahm) pl. n.

see INFANTILE (SPASMS).

Back  -    New Search

salbutamol (sal-bew-t-mol) n.

a drug that stimulates beta-adrenergic receptors (see SYMPATHOMIMETIC). It is administered by mouth, injection, or inhalation as a bronchodilator to relieve asthma, chronic bronchitis, and emphysema. Trade name: Ventolin .

Back  -    New Search

salicylate (s-lis-i-layt) n.

a salt of salicylic acid. See METHYL SALICYLATE, SODIUM SALICYLATE.

Back  -    New Search

salicylic acid (sal-i-sil-ik) n.

a drug that causes the skin to peel and destroys bacteria and fungi. It is applied to the skin to treat ulcers, dandruff, eczema, psoriasis, warts, and corns.

Back  -    New Search

salicylism (sal-i-sil-izm) n.

poisoning due to an overdose of aspirin or other salicylate-containing compounds. The main symptoms are headache, dizziness, tinnitus, disturbances of vision, and vomiting.

Back  -    New Search

saline (normal saline) (say-lyn) n.

a solution containing 0.9% sodium chloride. Saline may be used clinically as a diluent for drugs administered by injection and as a plasma substitute.

Back  -    New Search

saliva (s-ly-v) n.

the alkaline liquid secreted by the salivary glands and the mucous membrane of the mouth. Its principal constituents are water and mucus, which keep the mouth moist and lubricate food, and enzymes (e.g. amylase) that begin the digestion of starch. See also DRY MOUTH.
—salivary (s-ly-ver-i) adj.

Back  -    New Search

salivary gland n.

a gland that produces saliva. There are three pairs of salivary glands: the parotid glands, sublingual glands, and submandibular glands (see illustration).

Back  -    New Search

salivary stone n.

see SIALOLITH.

Back  -    New Search

salivation (sal-i-vay-shn) n.

the secretion of saliva by the salivary glands of the mouth, increased in response to the chewing action of the jaws or to the thought, taste, smell, or sight of food. See also PTYALISM.

Back  -    New Search

Salk vaccine (sawlk) n.

a vaccine against poliomyelitis. It is administered by injection. [J. E. Salk (1914–95), US bacteriologist]

Back  -    New Search

salmeterol (sal-mee-ter-ol) n.

a sympathomimetic bronchodilator drug used to treat severe asthma. It is administered by metered-dose aerosol inhaler. Trade name: Serevent .

Back  -    New Search

Salmonella (sal-m-nel-) n.

a genus of Gram-negative motile rodlike bacteria that inhabit the intestines of animals and man. Certain species cause such diseases as food poisoning, gastroenteritis, and septicaemia. S. paratyphi a species that causes paratyphoid fever. S. typhi a species that causes typhoid fever.

Back  -    New Search

salmonellosis (sal-m-nel-oh-sis) n.

an infestation of the digestive system by bacteria of the genus Salmonella. See also FOOD POISONING.

Back  -    New Search

salping- (salpingo-) prefix

denoting 1 the Fallopian tube.

2 the auditory canal (meatus).
Top

Back  -    New Search

salpingectomy (sal-pin-jek-tmi) n.

the surgical removal of a Fallopian tube. The operation involving both tubes is a permanent and completely effective method of sterilization.

Back  -    New Search

salpingitis (sal-pin-jy-tis) n.

inflammation of a tube, most commonly of one or both of the Fallopian tubes caused by bacterial infection spreading from the vagina or uterus or carried in the blood. acute s. salpingitis in which there is sharp pain in the lower abdomen. The infection may spread to the peritoneum (see PERITONITIS); in severe cases the tubes may become blocked with scar tissue.

Back  -    New Search

salpingography (sal-ping-og-rfi) n.

radiography of one or both Fallopian tubes after a radiopaque substance has been introduced into them via an injection into the uterus. standardized selective s. salpingography combined with tubal catheterization, which enables occluded tubes to be restored to patency.

Back  -    New Search

salpingolysis (sal-ping-ol-i-sis) n.

a surgical operation carried out to restore patency to blocked Fallopian tubes; it involves the division and removal of adhesions around the ovarian ends of the tubes.

Back  -    New Search

salpingo-oophorectomy (sal-ping-oh-oh--f-rek-tmi) n.

surgical removal of a Fallopian tube and the ovary associated with it.

Back  -    New Search

salpingo-oophoritis (sal-ping-oh-oh--f-ry-tis) n.

inflammation of a Fallopian tube and an ovary.

Back  -    New Search

salpingostomy (sal-ping-ost-mi) n.

the surgical creation of an artificial opening in a blocked Fallopian tube in order to restore its patency.

Back  -    New Search

salpinx (sal-pinks) n.

(in anatomy) a tube, especially a Fallopian tube or the external auditory meatus.

Back  -    New Search

salt (sawlt) n.

(in chemistry) a compound formed when the hydrogen in an acid is replaced by a metal. An acid and a base react together to form a salt and water. common s. see SODIUM CHLORIDE. s. depletion excessive loss of sodium chloride from the body. This may result from sweating, persistent vomiting or diarrhoea, or loss of fluid in wounds. The main symptoms are muscular weakness and cramps.

Back  -    New Search

salvage procedure (sal-vij) n.

measures to palliate the worst effects of a tumour but with no aim to effect a cure.

Back  -    New Search

sanatorium (san--tor-im) n.

1 a hospital or institution for the rehabilitation and convalescence of patients of any kind.

2 an institution for patients who have suffered from pulmonary tuberculosis.
Top

Back  -    New Search

sandfly fever (sand-fly) n.

a viral influenza-like disease transmitted to man by the bite of the sandfly Phlebotomus pa patasii. Sandfly fever occurs principally in countries surrounding the Persian Gulf and the tropical Mediterranean.

Back  -    New Search

sandwich therapy (sand-wich) n.

a combination of treatments in which one type of therapy (e.g. a surgical operation) is ‘sandwiched’ between exposures to another treatment (e.g. pre- and postoperative radiotherapy). See also COMBINED THERAPY.

Back  -    New Search

sangui- (sanguino-) prefix

denoting blood.

Back  -    New Search

sanguineous (sang-win-is) adj.

1 containing, stained, or covered with blood.

2 (of tissues) containing more than the normal quantity of blood.
Top

Back  -    New Search

sanies (say-ni-eez) n.

a foul-smelling watery discharge from a wound or ulcer, containing serum, blood, and pus.

Back  -    New Search

saphena (s-fee-n) n.

see SAPHENOUS VEIN.

Back  -    New Search

saphena varix n.

an abnormal dilatation of the terminal section of the long saphenous vein in the groin.

Back  -    New Search

saphenous nerve (s-fee-ns) n.

a large branch of the femoral nerve that supplies the skin from the knee to below the ankle with sensory nerves.

Back  -    New Search

saphenous vein (saphena) n.

either of two superficial veins of the leg, draining blood from the foot. long s. v. the longest vein in the body, running from the foot to the groin. short s. v. the vein that runs up the back of the calf.

Back  -    New Search

saponify (s-pon-i-fy) vb.

(in chemistry) to hydrolyse an ester with a hydroxide, especially a fat with a hydroxide to form a soap.
—saponification n.

Back  -    New Search

sapr- (sapro-) prefix

denoting 1 putrefaction.

2 decaying matter.
Top

Back  -    New Search

sapraemia (sap-ree-mi) n.

blood poisoning by toxins of saprophytic bacteria. Compare PYAEMIA, SEPTICAEMIA, TOXAEMIA.

Back  -    New Search

saprophyte (sap-roh-fyt) n.

any free-living organism that lives and feeds on the dead and putrefying tissues of animals or plants. Compare PARASITE.
—saprophytic (sap-roh-fit-ik) adj.

Back  -    New Search

sarc- (sarco-) prefix

denoting 1 flesh or fleshy tissue.

2 muscle.
Top

Back  -    New Search

sarcoid (sar-koid)

1 adj. fleshy.

2 n. a fleshy tumour.
Top

Back  -    New Search

sarcoidosis (Boeck's disease) (sar-koid-oh-sis) n.

a chronic disorder of unknown cause in which the lymph nodes in many parts of the body are enlarged and granulomas develop in the lungs, liver, and spleen. The skin, nervous system, eyes, and salivary glands are also commonly affected, and the condition has features similar to tuberculosis.

Back  -    New Search

sarcolemma (sar-koh-lem-) n.

the cell membrane that encloses a muscle cell (muscle fibre).

Back  -    New Search

sarcoma (sar-koh-m) n.

any cancer of connective tissue. These tumours may occur in any part of the body; they arise in fibrous tissue, muscle, fat, bone, cartilage, synovium, blood and lymphatic vessels, and various other tissues. s. botryoides see CARCINOSARCOMA. See also CHONDROSARCOMA, FIBROSARCOMA, LEIOMYOSARCOMA, LIPOSARCOMA, LYMPHANGIOSARCOMA, OSTEOSARCOMA, RHABDOMYOSARCOMA.
—sarcomatous adj.

Back  -    New Search

sarcomatosis (sar-koh-m-toh-sis) n.

sarcoma that has spread widely throughout the body, most commonly through the bloodstream.

Back  -    New Search

sarcoplasm (myoplasm) (sar-koh-plazm) n.

the cytoplasm of muscle cells.

Back  -    New Search

Sarcoptes (sar-kop-teez) n.

a genus of small oval mites. S. scabiei the scabies mite. The female tunnels into the skin, where it lays its eggs. The presence of the mites causes severe irritation, which eventually leads to scabies.

Back  -    New Search

sartorius (sar-tor-is) n.

a narrow ribbonlike muscle at the front of the thigh. The longest muscle in the body, the sartorius flexes the leg on the thigh and the thigh on the abdomen.

Back  -    New Search

saucerization (saw-ser-l-zay-shn) n.

1 an operation in which tissue is cut away from a wound to form a saucer-like depression. It is carried out to facilitate healing of injuries or disorders in which bone is infected.

2 the concave appearance of the upper surface of a vertebra that has been fractured by compression.
Top

Back  -    New Search

Sayre's jacket (say-erz) n.

a plaster of Paris cast used to support the backbone when the vertebrae have been severely damaged by disease, such as tuberculosis. [L. A. Sayre (1820–1900), US surgeon]

Back  -    New Search

scab (skab) n.

a hard crust of dried blood, serum, or pus that develops over a sore, cut, or scratch.

Back  -    New Search

scabicide (skay-bi-syd) n.

a drug that kills the mites causing scabies.

Back  -    New Search

scabies (skay-beez) n.

a skin infection caused by the mite Sarcoptes scabiei. Scabies is typified by severe itching, red papules, and often secondary infection. The mites pass from person to person by close contact. Commonly infected areas are the penis, nipples, and the finger webs. Treatment is by application of a scabicide, usually permethrin, lindane, or malathion, to all areas of the body from the neck down; benzyl benzoate may be used but is more irritant.

Back  -    New Search

scala (skay-l) n.

one of the spiral canals of the cochlea.

Back  -    New Search

scald (skawld) n.

a burn produced by a hot liquid or vapour, such as boiling water or steam.

Back  -    New Search

scale (skayl)

1 n. any of the flakes of dead epidermal cells shed from the skin.

2 vb. to scrape deposits of calculus from the teeth (see SCALER).
Top

Back  -    New Search

scalenus (skay-leen-s) n.

one of four paired muscles of the neck (s. anterior , medius , minimus , and posterior ). They are responsible for raising the first and second ribs in inspiration and for bending the neck forward and to either side.

Back  -    New Search

scalenus syndrome (thoracic outlet syndrome) n.

the group of symptoms caused by compression of the subclavian artery and the lower roots of the brachial plexus against the outlet of the upper thoracic vertebrae. Loss of sensation and wasting may be found in the affected arm, which may also be painful.

Back  -    New Search

scaler (skayl-er) n.

an instrument for removing calculus from the teeth. It may be a hand instrument or one energized by rapid ultrasonic vibrations.

Back  -    New Search

scalp (skalp) n.

the skin that covers the cranium and is itself covered with hair.

Back  -    New Search

scalpel (skal-pl) n.

a small pointed surgical knife with a straight handle and usually detachable disposable blades of various shapes.

Back  -    New Search

scan (skan)

1 n. examination of the body or a part of the body using ultrasonography, computerized tomography (CT), magnetic resonance imaging (MRI), or scintigraphy.

2 n. the image obtained from such an examination.
Top

3 vb. to examine the body using any of these techniques.
Top

Back  -    New Search

scanning speech (skan-ing) n.

a disorder of articulation in which the syllables are inappropriately separated and equally stressed. It is caused by cerebellar disease.

Back  -    New Search

scaphocephaly (skaf-oh-sef-li) n.

an abnormally long and narrow skull due to premature closure of the sagittal suture.
—scaphocephalic (skaf-oh-si-fal-ik) adj.

Back  -    New Search

scaphoid bone (skay-foid) n.

a boat-shaped bone of the wrist (see CARPUS). It articulates with the trapezium and trapezoid bones in front, with the radius behind, and with the capitate and lunate medially. It is commonly injured by falls; for example, a scaphoid fracture is usually caused by a fall onto the outstretched hand.

Back  -    New Search

scapul- (scapulo-) prefix

denoting the scapula.

Back  -    New Search

scapula (skap-yoo-l) n. (pl. scapulas or scapulae)

the shoulder blade: a triangular bone, a pair of which form the back part of the shoulder girdle.
—scapular adj.

Back  -    New Search

scar (skar) n.

see CICATRIX.

Back  -    New Search

scarification (ska-rifi-kay-shn) n.

the process of making a series of shallow cuts or scratches in the skin to allow a substance, such as a droplet of smallpox vaccine, to penetrate the body.

Back  -    New Search

scarlatina (skar-l-tee-n) n.

see SCARLET FEVER.

Back  -    New Search

scarlet fever (skar-lit) n.

a highly contagious disease caused by toxin-producing bacteria of the genus Streptococcus. The symptoms include fever, tonsillitis, and a widespread scarlet rash; the tongue is also affected, becoming bright red. Treatment with antibiotics reduces the risk of secondary complications, such as ear and kidney inflammation. Medical name: scarlatina . Compare GERMAN MEASLES.

Back  -    New Search

Scarpa's triangle (skar-pz) n.

see FEMORAL (TRIANGLE). [A. Scarpa (1747–1832), Italian anatomist and surgeon]

Back  -    New Search

scat- (scato-) prefix

denoting faeces.

Back  -    New Search

SCC n.

see SQUAMOUS CELL CARCINOMA.

Back  -    New Search

Scheuermann's disease (shoi-er-manz) n.

a form of osteochondritis affecting the vertebrae. It develops in adolescents and causes spinal pain and outward curvature of the spine (kyphosis). [H. W. Scheuermann (1877–1960), Danish surgeon]

Back  -    New Search

Schick test (shik) n.

a test to determine whether a person is susceptible to diphtheria. A small quantity of diphtheria toxin is injected under the skin; a patch of reddening and swelling shows that the person has no immunity. [B. Schick (1877–1967), US paediatrician]

Back  -    New Search

Schilling test (shil-ing) n.

a test used to assess a patient's capacity to absorb vitamin B_12 from the bowel. Radioactive vitamin B_12 is given by mouth and urine collected. A patient with pernicious anaemia will excrete less than 5% of the original dose over a period of 24 hours. [R. F. Schilling (1919– ), US physician]

Back  -    New Search

schindylesis (skin-di-lee-sis) n.

a form of synarthrosis (immovable joint) in which a crest of one bone fits into a groove of another.

Back  -    New Search

-schisis suffix

denoting a cleft or split.

Back  -    New Search

schisto- prefix

denoting a fissure; split.

Back  -    New Search

Schistosoma (Bilharzia) (shist--soh-m) n.

a genus of blood flukes, three species of which are important parasites of man causing the tropical disease schistosomiasis.

Back  -    New Search

schistosomiasis (bilharziasis) (shist--soh-my--sis) n.

a tropical disease caused by blood flukes of the genus Schistosoma. The disease is contracted when larvae penetrate the skin of anyone bathing in infected water. Adult flukes eventually settle in the blood vessels of the intestine (S. mansoni and S. japonicum) or bladder (S. haematobium); the release of their spiked eggs causes anaemia, inflammation, and the formation of scar tissue. Additional symptoms include diarrhoea, dysentery, cirrhosis of the liver, haematuria, and cystitis. The disease is treated with various drugs, including stibophen and niridazole.

Back  -    New Search

schiz- (schizo-) prefix

denoting a split or division.

Back  -    New Search

schizoid personality (skits-oid) n.

a personality characterized by solitariness, emotional coldness to others, inability to experience pleasure, lack of response to praise and criticism, withdrawal into a fantasy world, excessive introspection, and eccentricity of behaviour. See PERSONALITY DISORDER.

Back  -    New Search

schizophrenia (skits--freen-i) n.

a severe mental disorder (or group of disorders) characterized by a disintegration of the process of thinking, of contact with reality, and of emotional responsiveness. The patient suffers from hallucinations and delusions and feels that his thoughts, sensations, and actions are controlled by, or shared with, others. Treatment is with phenothiazines and other antipsychotic drugs and with vigorous psychological and social management and rehabilitation. catatonic s. schizophrenia in which there are marked motor disturbances; this form is now rare. hebephrenic s. see HEBEPHRENIA. paranoid s. schizophrenia characterized by prominent delusions. simple s. schizophrenia in which increasing social withdrawal and personal ineffectiveness are the major changes.
—schizophrenic (skits--fren-ik) adj.

Back  -    New Search

Schlatter's disease (shlat-erz) n.

see OSGOOD-SCHLATTER DISEASE.

Back  -    New Search

Schlemm's canal (shlemz) n.

a channel in the eye, at the junction of the cornea and the sclera, through which the aqueous humour drains. [F. Schlemm (1795–1858), German anatomist]

Back  -    New Search

Schönlein-Henoch purpura n.

see HENOCH-SCHÖNLEIN PURPURA.

Back  -    New Search

school health service (skool) n.

(in Britain) a service concerned with the early detection of physical and emotional abnormalities in schoolchildren and their subsequent treatment and surveillance.

Back  -    New Search

school nurse n.

a registered nurse who has undertaken a course in the health care of school-age children. A member of the school health service, she is responsible for monitoring growth and development, conducting routine examinations, and treating minor ailments.

Back  -    New Search

Schwann cells (shwon) pl. n.

the cells that lay down the myelin sheath around the axon of a medullated nerve fibre. [T. Schwann (1810–82), German anatomist and physiologist]

Back  -    New Search

Schwannoma (shwon-oh-m) n.

see NEUROFIBROMA.

Back  -    New Search

Schwartze's operation (shvarts-z) n.

an operation to open and drain the air cells in the mastoid in severe cases of mastoiditis. [H. H. R. Schwartze (1837–1910), German otologist]

Back  -    New Search

sciatica (sy-at-ik-) n.

pain felt down the back and outer side of the thigh, leg, and foot. It is usually caused by degeneration of an intervertebral disc, which protrudes laterally to compress a spinal nerve root. The onset may be sudden, brought on by an awkward lifting or twisting movement.

Back  -    New Search

sciatic nerve (sy-at-ik) n.

the major nerve of the leg and the nerve with the largest diameter. It runs down behind the thigh from the lower end of the spine.

Back  -    New Search

SCID n.

see SEVERE COMBINED IMMUNODEFICIENCY DISEASE.

Back  -    New Search

scintigram (sin-ti-gram) n.

a diagram showing the distribution of radioactive tracer in a part of the body, produced by recording the flashes of light given off by a scintillator as it is struck by radiation of different intensities. This technique is called scintigraphy . By scanning the body, section by section, a ‘map’ of the radioactivity in various regions is built up, aiding the diagnosis of cancer or other disorders. Such a record is known as a scintiscan .

Back  -    New Search

scintillator (sin-ti-lay-ter) n.

a substance that produces a fluorescent flash when struck by high-energy radiation, such as beta or gamma rays. A scintillator forms the basis of a gamma camera. See also SCINTIGRAM.

Back  -    New Search

scintiscan (sin-ti-skan) n.

see SCINTIGRAM.

Back  -    New Search

scirrhous (si-rs) adj.

describing carcinomas that are stony hard to the touch. Such a carcinoma is known as a scirrhus .

Back  -    New Search

scissor leg (siz-er) n.

a disability in which one leg becomes permanently crossed over the other as a result of spasticity of its adductor muscles or deformity of the hip. The condition occurs in children with brain damage and in adults after strokes.

Back  -    New Search

scissura (scissure) (si-zhor-) n.

a cleft or splitting, such as the splitting open of tissues when a hernia forms.

Back  -    New Search

scler- (sclero-) prefix

denoting 1 hardening or thickening.

2 the sclera.
Top

3 sclerosis.
Top

Back  -    New Search

sclera (sclerotic coat) (skleer-) n.

the white fibrous outer layer of the eyeball. At the front of the eye it becomes the cornea. See EYE.
—scleral adj.

Back  -    New Search

scleritis (skleer-l-tis) n.

inflammation of the sclera.

Back  -    New Search

scleroderma (skleer-oh-der-m) n.

thickening of the skin, either localized (see MORPHOEA) or generalized, resulting in waxy ivory-coloured areas. Scleroderma may be an autoimmune disease. Systemic sclerosis is a related multisystem disorder.

Back  -    New Search

scleromalacia (skleer-oh-m-lay-shi) n.

thinning of the sclera (white of the eye) as a result of inflammation.

Back  -    New Search

sclerosis (skleer-oh-sis) n.

hardening of tissue, usually due to scarring (fibrosis) after inflammation or to ageing. It can affect the lateral columns of the spinal cord and the medulla of the brain (amyo-trophic lateral s. or Lou Gehrig's disease ), causing progressive muscular paralysis (see MOTOR NEURONE DISEASE). See also ARTERIOSCLEROSIS, ATHEROSCLEROSIS, MULTIPLE SCLEROSIS, SYSTEMIC (SCLEROSIS), TUBEROUS (SCLEROSIS).

Back  -    New Search

sclerotherapy (skleer-oh-th'e-r-pi) n.

treatment of varicose veins by the injection of an irritant solution. This causes thrombophlebitis, which encourages obliteration of the varicose vein by thrombosis and subsequent scarring. Sclerotherapy is also used for treating haemorrhoids and oesophageal varices.

Back  -    New Search

sclerotic (skleer-ot-ik)

1 (or sclerotic coat) n. see SCLERA.

2 adj. affected with sclerosis.
Top

Back  -    New Search

sclerotome (skleer--tohm) n.

a surgical knife used in the operation of sclerotomy.

Back  -    New Search

sclerotomy (skleer-ot-mi) n.

an operation in which an incision is made in the sclera.

Back  -    New Search

scolex (skoh-leks) n. (pl. scolices)

the head of a tapeworm. Suckers and/or hooks on the scolex enable the worm to attach itself to the wall of its host's gut.

Back  -    New Search

scoliosis (skoh-li-oh-sis) n.

lateral (sideways) deviation of the backbone, caused by congenital or acquired abnormalities of the vertebrae, muscles, and nerves. See also KYPHOSIS, KYPHOSCOLIOSIS.

Back  -    New Search

-scope suffix

denoting an instrument for observing or examining.

Back  -    New Search

scopolamine (sk-pol--meen) n.

see HYOSCINE.

Back  -    New Search

scorbutic (skor-bew-tik) adj.

affected with scurvy.

Back  -    New Search

scoring system (skor-ing) n.

any of various methods in which the application of an agreed numerical scale is used as a means of estimating the degree of a clinical situation, e.g. the severity of an injury, the degree of patient recovery, or the extent of malignancy. Examples include the Glasgow scoring system and the injury scoring system.

Back  -    New Search

scoto- prefix

denoting darkness.

Back  -    New Search

scotoma (skoh-toh-m) n. (pl. scotomata)

a small area of abnormally less sensitive or absent vision in the visual field, surrounded by normal sight.

Back  -    New Search

scotometer (skoh-tom-it-er) n.

an instrument used for mapping defects in the visual field. See also PERIMETER.

Back  -    New Search

scotopic (skoh-top-ik) adj.

relating to or describing conditions of poor illumination. s. vision vision in dim light in which the rods of the retina are involved (see DARK ADAPTATION).

Back  -    New Search

screening test (skreen-ing) n.

a test carried out on a large number of apparently healthy people to separate those who probably have a specified disease from those who do not. Examples are the Guthrie test, cervical smears, and Forrest screening. See also GENETIC SCREENING.

Back  -    New Search

scrofula (skrof-yoo-l) n.

tuberculosis of lymph nodes, usually those in the neck, causing the formation of abscesses. Treatment with antituberculous drugs is effective. The disease, which is now rare, most commonly affects young children.
—scrofulous adj.

Back  -    New Search

scrofuloderma (skrof-yoo-loh-der-m) n.

tuberculosis of the skin in which the skin breaks down over suppurating tuberculous glands, with the formation of irregular-shaped ulcers with blue-tinged edges. Treatment is with antituberculous drugs.

Back  -    New Search

scrototomy (skroh-tot-mi) n.

an operation in which the scrotum is surgically explored, usually undertaken to investigate patients with probable obstructive azoospermia.

Back  -    New Search

scrotum (skroh-tm) n.

the paired sac that holds the testes and epididymides outside the abdominal cavity. Its function is to allow the production and storage of spermatozoa to occur at a lower temperature than that of the abdomen.
—scrotal adj.

Back  -    New Search

scrub typhus (tsutsugamushi disease) (skrub) n.

a disease, widely distributed in SE Asia, caused by the parasitic microorganism Rickettsia tsutsugamushi and transmitted to man through the bite of mites. Symptoms include headache, chills, high temperature, a red rash, a cough, and delirium. A small ulcer forms at the site of the bite. Scrub typhus is treated with tetracycline antibiotics. See also RICKETTSIAE, TYPHUS.

Back  -    New Search

scrum-pox (skrum-poks) n.

a form of herpes simplex found in rugby players and wrestlers. It is caused by abrasive contact.

Back  -    New Search

scurvy (sker-vi) n.

a disease that is caused by a deficiency of vitamin C, which in humans cannot be synthesized and must be obtained from fresh fruit and vegetables. The first sign of scurvy is swollen bleeding gums, and a rash of tiny bleeding spots around the hair follicles is characteristic; this may be followed by subcutaneous bleeding. Treatment with vitamin C soon reverses the effects.

Back  -    New Search

scybalum (sib--lm) n.

a lump or mass of hard faeces.

Back  -    New Search

seasickness (see-sik-nis) n.

see MOTION SICKNESS.

Back  -    New Search

seasonal affective disorder syndrome (see-z-nl) n.

see SADS.

Back  -    New Search

seat-belt syndrome (seet-belt) n.

thoracic injuries that arise from violent contact with a restraining seat belt in motor vehicle accidents occurring at high speeds.

Back  -    New Search

sebaceous cyst (si-bay-shs) n.

1 (epidermoid cyst, wen) a pale or flesh-coloured dome-shaped cyst that commonly occurs in adults, especially on the face, neck, or trunk. It is firm, with a central dot, and contains keratin. It is usually removed surgically.

2 a cyst of the sebaceous glands occurring in multiple form in a rare inherited condition, steatocystoma multiplex .
Top

Back  -    New Search

sebaceous gland

n. any of the simple or branched glands in the skin that secrete an oily substance, sebum. They open into hair follicles and their secretion is produced by the disintegration of their cells.

Back  -    New Search

seborrhoea (seb--ree-) n.

excessive secretion of sebum by the sebaceous glands. The glands are enlarged, especially on the nose and central face. The condition predisposes to acne and is common at puberty. Seborrhoea is sometimes associated with a kind of eczema (seborrhoeic eczema).
—seborrhoeic adj.

Back  -    New Search

sebum (see-bm) n.

the oily substance secreted by the sebaceous glands. Sebum provides a thin film of fat over the skin, which slows the evaporation of water; it also has an antibacterial effect.

Back  -    New Search

secondary health care (sek-nd-er-i) n.

health care provided by medical specialists or hospital staff members for a patient whose primary care was provided by the general practitioner who first diagnosed or treated the patient. For example, a general practitioner who accepts a patient with an unusual skin condition provides primary care but if he refers the patient to a dermatologist, the skin specialist becomes the source of secondary care. Compare TERTIARY HEALTH CARE.

Back  -    New Search

secondary prevention

n. the avoidance or alleviation of the serious consequences of disease by early detection.

Back  -    New Search

secondary sexual characteristics pl. n.

the physical characteristics that develop after puberty. In boys they include the growth of facial and pubic hair and the breaking of the voice. In girls they include the growth of public hair and the development of the breasts.

Back  -    New Search

second-level nurse (sek-nd lev-l) n.

a person who, having completed a nursing course, provides nursing care under the direction of a first-level nurse. A secondlevel nurse participates in the assessment and implementation of nursing care and works in a team with other nurses, medical and paramedical staff, and social workers. See ENROLLED NURSE.

Back  -    New Search

second messenger

n. an organic molecule that acts within a cell to initiate the response to a signal carried by a chemical messenger (e.g. a hormone) that does not itself enter the cell. Examples of second messengers are inositol triphosphate and cyclic AMP.

Back  -    New Search

secretin (si-kree-tin) n.

a hormone secreted from the duodenum when acidified food leaves the stomach. Secretin stimulates the secretion of relatively enzyme-free alkaline juice by the pancreas and of bile by the liver.

Back  -    New Search

secretion (si-kree-shn) n.

1 the process by which a gland isolates constituents of the blood or tissue fluid and chemically alters them to produce a substance that it discharges for use by the body or excretes.

2 the substance that is produced by a gland.
Top

Back  -    New Search

section (sek-shn)

1 n. (in surgery) the act of cutting (the cut or division made is also called a section).

2 n. (in microscopy) a thin slice of the specimen to be examined under a microscope.
Top

3 vb. to issue an order for compulsory admission to a psychiatric hospital under the appropriate section of the Mental Health Act.
Top

Back  -    New Search

Section 47

n. a section of the National Assistance Act 1948 that enables a local authority to arrange for the compulsory removal to a place of care of a person who is unwilling to go voluntarily from his or her own home. It can be applied to individuals who are suffering from a grave chronic disease, or are physically incapacitated, or are living in insanitary conditions because of old age or infirmity.

Back  -    New Search

security object (si-kewr-iti ob-jikt) n.

a particular item that brings comfort and a sense of security to a young child, often for a number of years. Security objects are usually associated in some way with bed and sleep. There is no reason to suppose that they are in any way undesirable, at any age.

Back  -    New Search

sedation (si-day-shn) n.

the production of a restful state of mind, particularly by the use of drugs (see SEDATIVE).

Back  -    New Search

sedative (sed--tiv) n.

a drug that has a calming effect, relieving anxiety and tension. See also TRANQUILLIZER.

Back  -    New Search

sedimentation rate (sed-i-men-tay-shn) n.

the rate at which solid particles sink in a liquid under the influence of gravity. See also ESR (ERYTHROCYTE SEDIMENTATION RATE).

Back  -    New Search

segment (seg-mnt) n.

(in anatomy) a portion of a tissue or an organ (e.g. the uterus or the eye), usually distinguishable from other portions by lines of demarcation.

Back  -    New Search

Seidlitz powder (sed-lits) n.

a mixture of sodium bicarbonate, sodium potassium tartrate, and tartaric acid, taken as a laxative when dissolved in water.

Back  -    New Search

selective serotonin reuptake inhibitor (si-lek-tiv) n.

see SSRI.

Back  -    New Search

selegiline (sel-ej-i-leen) n.

a selective MAO inhibitor used in the treatment of parkinsonism. It is administered by mouth. Trade name: Eldepryl .

Back  -    New Search

selenium (si-lee-nim) n.

a trace element that has important antioxidant properties. It is also known to be an essential component of the enzyme that catalyses the production of triiodothyronine (T_3) from thyroxine (T_4) in the thyroid gland. Symbol: Se.

Back  -    New Search

selenium sulphide (sul-fyd) n.

a selenium compound with antifungal properties, used to treat dandruff and scalp infections. It is administered in a shampoo. Trade names: Lenium , Selsun .

Back  -    New Search

self-actualization (self-ak-tew--ly-zay-shn) n.

the tendency to realize and fulfil one's maximum potential. See MASLOW'S HIERARCHY OF HUMAN NEEDS.

Back  -    New Search

self-care (self-kair) n.

the practice of activities that are necessary to sustain life and health, normally initiated and carried out by the individual for himself.

Back  -    New Search

self-catheterization (self-kath-it-er-l-zay-shn) n.

see INTERMITTENT SELF-CATHETERIZATION.

Back  -    New Search

sella turcica (sel- ter-sik-) n.

a depression in the body of the sphenoid bone that encloses the pituitary gland.

Back  -    New Search

semeiology (see-mi-ol-ji) n.

see SYMPTOMATOLOGY.

Back  -    New Search

semen (seminal fluid) (see-men) n.

the fluid ejaculated from the penis at sexual climax. Each ejaculate may contain 300–500 million sperms suspended in a fluid secreted by the prostate gland and seminal vesicles with a small contribution from Cowper's glands.
—seminal (sem-in-l) adj.

Back  -    New Search

semi- prefix

denoting half.

Back  -    New Search

semicircular canals (sem-i-ser-kew-ler) pl. n.

three tubes that form part of the membranous labyrinth of the ear. They are concerned with balance and each canal registers movement in a different plane.

Back  -    New Search

semilunar cartilage (sem-i-loo-ner) n.

one of a pair of crescent-shaped cartilages in the knee joint situated between the femur and tibia.

Back  -    New Search

semilunar valve n.

either of the two valves in the heart situated at the origin of the aorta (aortic valve ) and the pulmonary artery (pulmonary valve ). Each consists of three flaps (cusps), which maintain the flow of blood in one direction.

Back  -    New Search

seminal analysis n.

analysis of a specimen of semen, which should be obtained after five days of abstinence from coitus, in order to assess male fertility. It includes determinations of the concentration and motility of the sperm and detection of the presence of abnormal forms of sperm. See also SPERM COUNT.

Back  -    New Search

seminal vesicle n.

either of a pair of male accessory sex glands that open into the vas deferens. The seminal vesicles secrete most of the liquid component of semen.

Back  -    New Search

seminiferous tubule (sem-in-if-er-s) n.

any of the long convoluted tubules that make up the bulk of the testis.

Back  -    New Search

seminoma (sem-in-oh-m) n.

a malignant tumour of the testis, appearing as a swelling, often painless, in the scrotum. The best treatment for localized disease is orchidectomy. A similar tumour occurs in the ovary (see DYSGERMINOMA).

Back  -    New Search

semipermeable membrane (sem-i-per-mi-bl) n.

a membrane that allows the passage of some molecules but not others. Semipermeable membranes are used clinically in haemodialysis.

Back  -    New Search

semiprone (sem-i-prohn) adj.

describing the position of a patient lying face downwards, but with one or both knees flexed to one side. Compare PRONE, SUPINE.

Back  -    New Search

senescence (si-nes-ns) n.

the condition of ageing, which is often marked by a decrease in physical and mental abilities.
—senescent adj.

Back  -    New Search

Sengstaken tube (sengz-tay-kn) n.

a tube containing a triple lumen and inflatable balloons that is passed down the oesophagus to the stomach to compress bleeding oesophageal varicose veins. [R. W. Sengstaken (1923– ), US neurosurgeon]

Back  -    New Search

senile dementia (see-nyl) n.

loss of the intellectual faculties, often associated with behavioural deterioration, beginning for the first time in old age. See alsoDEMENTIA.

Back  -    New Search

senility (sin-il-iti) n.

the state of physical and mental deterioration that is associated with the ageing process.
—senile adj.

Back  -    New Search

senna (sen-) n.

the dried fruits of certain shrubs of the genus Cassia, administered by mouth as an irritant laxative to relieve constipation and to empty the bowels before X-ray examination. Trade name: Senokot .

Back  -    New Search

sensation (sen-say-shn) n.

a feeling: the result of messages from the body's sensory receptors registering in the brain as information about the environment.

Back  -    New Search

sense (sens) n.

one of the faculties by which the qualities of the external environment are appreciated - sight, hearing, smell, taste, or touch. s. organ a collection of specialized cells (receptors), connected to the nervous system, that is capable of responding to a particular stimulus from either outside or inside the body.

Back  -    New Search

sensibility (sen-si-bil-iti) n.

the ability to be affected by, and respond to, changes in the surroundings. Sensibility is a characteristic of cells of the nervous system.

Back  -    New Search

sensible (sen-sibl) adj.

1 perceptible to the senses.

2 capable of sensibility.
Top

Back  -    New Search

sensitive (sen-sit-iv) adj.

possessing the ability to respond to a stimulus.

Back  -    New Search

sensitivity (sen-sit-iv-iti) n.

the degree to which a disease-causing organism responds to treatment by antibiotics or other drugs.

Back  -    New Search

sensitization (sen-si-ty-zay-shn) n.

1 alteration of the responsiveness of the body to the presence of foreign substances. In the development of an allergy, an individual becomes sensitized to a particular allergen. The phenomena of sensitization are due to the production of antibodies.

2 (in behaviour therapy) a form of aversion therapy in which anxiety-producing stimuli are associated with the unwanted behaviour.
Top

Back  -    New Search

sensory (sen-ser-i) adj.

relating to the input division of the nervous system, which carries information from receptors throughout the body towards the brain and spinal cord. s. cortex the region of the cerebral cortex responsible for receiving incoming information relayed by sensory nerve pathways from all parts of the body. s. deprivation a condition resulting from partial or complete absence of sensory stimuli, leading to confusion and disorientation. s. nerve see NERVE.

Back  -    New Search

sepsis (sep-sis) n.

the putrefactive destruction of tissues by disease-causing bacteria or their toxins.

Back  -    New Search

sept- (septi-) prefix

denoting 1 seven.

2 (or septo-) a septum, especially the nasal septum.
Top

3 sepsis.
Top

Back  -    New Search

septal defect (sep-t'l) n.

a hole in the partition (septum) between the left and right halves of the heart. This congenital condition is due to an abnormality of heart development in the fetus. It may be found between the two atria (atrial s. d. , ASD) or between the ventricles (ventricular s. d. , VSD). A septal defect permits abnormal circulation of blood from the left side of the heart to the right, which results in excessive blood flow through the lungs. Pulmonary hypertension develops and heart failure may occur. Large defects are closed surgically but small defects do not require treatment.

Back  -    New Search

septic (sep-tik) adj.

relating to or affected with sepsis. s. arthritis infection in a joint, which becomes swollen, hot, and tender; movement is painful and very restricted. The infecting organism enters the joint via the bloodstream or through a penetrating injury.

Back  -    New Search

septicaemia (septi-seem-i) n.

widespread destruction of tissues due to absorption of disease-causing bacteria or their toxins from the bloodstream. Compare PYAEMIA, SAPRAEMIA, TOXAEMIA.

Back  -    New Search

Septrin (sep-trin) n.

see CO-TRIMOXAZOLE.

Back  -    New Search

septum (sep-tm) n. (pl. septa)

a partition or dividing wall within an anatomical structure.
—septal adj. —septate (sep-tayt) adj.

Back  -    New Search

sequela (si-kwee-l) n. (pl. sequelae)

any disorder or pathological condition that results from a preceding disease or accident.

Back  -    New Search

sequestration (see-kwes-tray-shn) n.

1 the formation of a sequestrum and its separation from the surrounding tissue.

2 a separated part of an organ occurring as a developmental anomaly.
Top

Back  -    New Search

sequestrectomy (see-kwes-trek-tmi) n.

surgical removal of a sequestrum.

Back  -    New Search

sequestrum (si-kwes-trm) n. (pl. sequestra)

a portion of dead bone formed in an infected bone in chronic osteomyelitis. It can cause irritation and the formation of pus, which may discharge through a sinus, and is usually surgically removed.

Back  -    New Search

ser- (sero-) prefix

denoting 1 serum.

2 serous membrane.
Top

Back  -    New Search

serine (se-reen) n.

see AMINO ACID.

Back  -    New Search

seroconvert (seer-oh-kn-vert) vb.

to produce specific antibodies in response to the presence of an antigen (e.g. a vaccine or a virus). In AIDS patients seroconversion is accompanied by a sore throat, swollen lymph nodes, fever, and aches and pains.
—seroconversion n.

Back  -    New Search

serology (si-rol-ji) n.

the study of blood serum and its constituents, particularly their contribution to the protection of the body against disease.
—serological adj.

Back  -    New Search

seropus (seer-oh-pus) n.

a mixture of serum and pus, which forms, for example, in infected blisters.

Back  -    New Search

serosa (si-roh-s) n.

see SEROUS MEMBRANE.

Back  -    New Search

serositis (seer-oh-sy-tis) n.

inflammation of a serous membrane. See POLYSEROSITIS.

Back  -    New Search

serotherapy (seer-oh-th'e-r-pi) n.

the use of serum containing known antibodies (see ANTISERUM) to treat a patient with an infection or to confer temporary passive immunity upon a person at special risk.

Back  -    New Search

serotonin (5-hydroxytryptamine, 5-HT) (se-r-toh-nin) n.

a compound widely distributed in the tissues, particularly in the blood platelets, intestinal wall, and central nervous system. It is thought to play a role in inflammation similar to that of histamine and it is involved in the genesis of a migrainous headache. Serotonin also acts as a neurotransmitter, and its levels in the brain are believed to have an important effect on mood. See alsoSSRI.

Back  -    New Search

serotype (seer-oh-typ) n.

a category into which material is placed based on its serological activity, particularly in terms of the antigens it contains or the antibodies that may be produced against it.

Back  -    New Search

serous (seer-s) adj.

1 relating to or containing serum.

2 resembling serum or producing a fluid resembling serum.
Top

Back  -    New Search

serous membrane (serosa) n.

a smooth transparent membrane lining certain large cavities of the body, such as the abdomen (see PERITONEUM) and chest (see PLEURA). The parietal portion of the membrane lines the walls of the cavity, and the visceral portion covers the organs concerned. The two form a closed sac, the inner surface of which is moistened by a thin fluid derived from blood serum, allowing frictionless movement of organs within their cavities. Compare MUCOUS MEMBRANE.

Back  -    New Search

serpiginous (ser-pij-in-s) adj.

describing a creeping or extending skin lesion, especially one with a wavy edge.

Back  -    New Search

serrated (ser-ayt-id) adj.

having a sawtoothed edge.
—serration n.

Back  -    New Search

sertraline (ser-tr-leen) n.

an antidepressant drug that acts by prolonging the action of the neurotransmitter serotonin (5-hydroxytryptamine) in the brain (see SSRI). It is taken by mouth. Trade name: Lustral .

Back  -    New Search

serum (blood serum) (seer-m) n.

the fluid that separates from clotted blood or blood plasma that is allowed to stand. Serum is essentially similar in composition to plasma but lacks fibrinogen and other substances that are used in the coagulation process. s. sickness a reaction that sometimes occurs 7–12 days after injection of a quantity of foreign serum. The usual symptoms are rashes, fever, joint pains, and enlargement of the lymph nodes.

Back  -    New Search

sesamoid bone (ses--moid) n.

an oval nodule of bone that lies within a tendon and slides over another bony surface. The patella (kneecap) is a sesamoid bone.

Back  -    New Search

sessile (se-syl) adj.

(of a tumour) attached directly by its base without a stalk.

Back  -    New Search

severe combined immunodeficiency disease (SCID) (s-veer km-bynd) n.

a rare disorder that usually manifests itself within the first three months of life by severe bacterial, fungal, and viral infection. It is due to reduced numbers of T- and B-lymphocytes.

Back  -    New Search

Sever's disease (see-verz) n.

apophysitis caused by pulling at the point of insertion of the Achilles tendon into the calcaneus (heel bone), causing heel pain. [J. W. Sever (20th century), US orthopaedic surgeon]

Back  -    New Search

sexarche (seks-ar-ki) n.

the age when a person first engages in sexual intercourse.

Back  -    New Search

sex chromatin (seks) n.

chromatin found only in female cells and believed to represent a single X chromosome in a nondividing cell. It can be used to discover the sex of a baby before birth by examination of cells obtained by amniocentesis or chorionic villus sampling.

Back  -    New Search

sex chromosome n.

a chromosome that is involved in the determination of the sex of the individual. Women have two X chromosomes; men have one X chromosome and one Y chromosome. Compare AUTOSOME.

Back  -    New Search

sex hormone n.

any steroid hormone, produced mainly by the ovaries or testes, that is responsible for controlling sexual development and reproductive function. Oestrogens and progesterone are the female sex hormones; androgens are the male sex hormones.

Back  -    New Search

sex-linked (seks-linkt) adj.

describing genes (or the characteristics controlled by them) that are carried on the sex chromosomes. The genes for certain disorders, e.g. haemophilia, are carried on the X chromosome; these genes are disorders and described as X-linked .

Back  -    New Search

sexology (seks-ol-ji) n.

the study of sexual matters, including anatomy, physiology, behaviour, and techniques.

Back  -    New Search

sexual deviation (seks-yoo-l) n.

any sexual behaviour regarded as abnormal by society. The deviation may relate to the sexual object (as in fetishism) or the activity engaged in (for example, sadism and exhibitionism).

Back  -    New Search

sexual intercourse (in-ter-kors) n.

see COITUS.

Back  -    New Search

sexually transmitted disease (STD) n.

any disease transmitted by sexual intercourse, formerly known as venereal disease . STDs include AIDS, syphilis, gonorrhoea, genital herpes, Chlamydia infection, and soft sore. The medical specialty concerned with STDs is genito-urinary medicine .

Back  -    New Search

SFD adj.

small for dates: see INTRAUTERINE (GROWTH RETARDATION).

Back  -    New Search

SGOT n.

serum glutamic oxaloacetic transaminase. See ASPARTATE AMINOTRANSFERASE.

Back  -    New Search

SGPT n.

serum glutamic pyruvic transaminase. See ALANINE AMINOTRANSFERASE.

Back  -    New Search

sheath (sheeth) n.

(in anatomy) the layer of connective tissue that envelops structures such as nerves, arteries, tendons, and muscles.

Back  -    New Search

Sheehan's syndrome (shee-nz) n.

subnormal activity of the pituitary gland, causing amenorrhoea and infertility, resulting from a reduction in its blood supply, due to a major haemorrhage in pregnancy. [H. L. Sheehan (20th century), British pathologist]

Back  -    New Search

Shigella (shig-el-) n.

a genus of nonmotile rodlike Gram-negative bacteria normally present in the intestinal tract of man. Some species are pathogenic. S. dysenteriae a species associated with bacillary dysentery.

Back  -    New Search

shigellosis (shig-el-oh-sis) n.

an infestation of the digestive system by bacteria of the genus Shigella, causing bacillary dysentery.

Back  -    New Search

shin bone (shin) n.

see TIBIA.

Back  -    New Search

shingles (shing-lz) n.

see HERPES (ZOSTER).

Back  -    New Search

Shirodkar's operation (shi-rod-karz) n.

an operation in which the neck (cervix) of the uterus is closed by means of a pursestring suture in order to prevent miscarriage. [N. V. Shirodkar (1900–71), Indian obstetrician]

Back  -    New Search

shock (shok) n.

the condition associated with circulatory collapse, when the arterial blood pressure is too low to maintain an adequate supply of blood to the tissues. The patient has a cold sweaty pallid skin, a weak rapid pulse, irregular breathing, dry mouth, dilated pupils, and a reduced flow of urine. Shock may be due to a decrease in the volume of blood, as occurs after haemorrhage, dehydration, burns, etc., or it may be caused by reduced activity of the heart, as in coronary thrombosis. It may also be due to widespread dilation of the veins so that there is insufficient blood to fill them. This may be caused by the presence of bacteria in the bloodstream (bacteraemic or toxic s. ); a severe allergic reaction (anaphylactic s. : see ANAPHYLAXIS), drug overdosage, e.g. overdosage of insulin produces hypoglycaemia (insulin s. ); or emotional shock (neurogenics .). See also SPINAL SHOCK.

Back  -    New Search

short circuit (short-ser-kit) n.

see ANASTOMOSIS.

Back  -    New Search

short-sightedness (short-syt-id-nis) n.

see MYOPIA.

Back  -    New Search

shoulder (shohl-der) n.

the ball-and-socket joint (see ENARTHROSIS) between the glenoid cavity of the scapula and the upper end (head) of the humerus. The joint is surrounded by a capsule closely associated with many tendons.

Back  -    New Search

shoulder girdle (pectoral girdle) n.

the bony structure to which the bones of the upper limbs are attached. It consists of the right and left scapulas and clavicles.

Back  -    New Search

show (shoh) n.

Informal . a discharge of blood-stained mucus from the vagina that occurs at the start of labour.

Back  -    New Search

shunt (shunt) n.

a passage connecting two anatomical channels and diverting blood or other fluid (e.g. cerebrospinal fluid) from one to the other. It may occur as a congenital abnormality (as in septal defects of the heart) or be surgically created. See also ANASTOMOSIS.

Back  -    New Search

sial- (sialo-) prefix

denoting 1 saliva.

2 a salivary gland.
Top

Back  -    New Search

sialadenitis (sy-l-ad-i-ny-tis) n.

inflammation of a salivary gland.

Back  -    New Search

sialagogue (sy-al--gog) n.

a drug that promotes the secretion of saliva. Parasympathomimetic drugs have this action.

Back  -    New Search

sialography (ptyalography) (sy--log-rfi) n.

X-ray examination of the salivary glands, after introducing a quantity of radiopaque material into the ducts of the salivary glands in the mouth.

Back  -    New Search

sialolith (sy-al-oh-lith) n.

a stone (calculus) in a salivary gland or duct. The flow of saliva is obstructed, causing swelling and intense pain.

Back  -    New Search

sialorrhoea (sy--l-ree-) n.

see PTYALISM.

Back  -    New Search

Siamese twins (conjoined twins) (sy--meez) pl. n.

identical twins that are physically joined together at birth. The condition ranges from twins joined only by the umbilical blood vessels to those in whom conjoined heads or trunk are inseparable.

Back  -    New Search

sib (sib) n.

see SIBLING.

Back  -    New Search

sibilant (sib-i-lnt) adj.

whistling or hissing. The term is applied to certain high-pitched abnormal sounds heard through a stethoscope.

Back  -    New Search

sibling (sib) (sib-ling) n.

one of a number of children of the same parents, i.e. a brother or sister.

Back  -    New Search

sickle-cell disease (drepanocytosis) (sik-l-sel) n.

a hereditary blood disease that mainly affects people of African ancestry. It occurs when the sickle-cell gene has been inherited from both parents and is characterized by the production of an abnormal type of haemoglobin, which precipitates in the red blood cells when the blood is deprived of oxygen. The affected cells are distorted into the characteristic sickle shape and are rapidly removed from the circulation, leading to anaemia.

Back  -    New Search

sickle-cell trait n.

the carrier condition of sickle-cell disease, in which the defective gene is inherited from only one parent. It generally causes no symptoms.

Back  -    New Search

side-effect (syd-i-fekt) n.

an unwanted effect produced by a drug in addition to its desired therapeutic effects. Side-effects may be harmful.

Back  -    New Search

sidero- prefix

denoting iron.

Back  -    New Search

sideropenia (sid-er-oh-pee-ni) n.

iron deficiency. This may result from dietary inadequacy; increased requirement of iron by the body, as in pregnancy or childhood; or increased loss of iron from the body, usually due to chronic bleeding.

Back  -    New Search

siderosis (sid-er-oh-sis) n.

the deposition of iron oxide dust in the lungs, occurring in silver finishers, arc welders, and haematite miners. Pulmonary fibrosis may develop if fibrogenic dusts such as silica are also inhaled.

Back  -    New Search

SIDS n.

sudden infant death syndrome: see COT DEATH.

Back  -    New Search

sievert (see-vt) n.

the SI unit of dose equivalent, being the dose equivalent when the absorbed dose of ionizing radiation multiplied by the stipulated dimensionless factors is 1 J kg-1. The sievert has replaced the rem. Symbol: Sv.

Back  -    New Search

sigmoid- prefix

denoting the sigmoid colon.

Back  -    New Search

sigmoid colon (sigmoid flexure) (sig-moid) n.

the S-shaped terminal part of the descending colon, which leads to the rectum.

Back  -    New Search

sigmoidectomy (sig-moid-ek-tmi) n.

removal of the sigmoid colon by surgery. It is performed for tumours, severe diverticular disease, or sigmoid volvulus.

Back  -    New Search

sigmoidoscope (sig-moid--skohp) n.

an instrument inserted through the anus in order to inspect the interior of the rectum and sigmoid colon.

Back  -    New Search

sigmoidoscopy (sig-moid-osk-pi) n.

examination of the rectum and sigmoid colon with a sigmoidoscope. It is used in the investigation of diarrhoea or rectal bleeding, particularly to detect colitis or cancer of the rectum.

Back  -    New Search

sigmoidostomy (sig-moid-ost-mi) n.

an operation in which the sigmoid colon is brought through the abdominal wall and opened. See COLOSTOMY.

Back  -    New Search

sign (syn) n.

an indication of a particular disorder that is observed by a physician but is not apparent to the patient. Compare SYMPTOM.

Back  -    New Search

silicone (sil-i-kohn) n.

any of a group of synthetic organic compounds of silicon that are water-repellant and are used in medicine in prostheses and as lubricants and adhesives.

Back  -    New Search

silicosis (sil-i-koh-sis) n.

a lung disease – a form of pneumoconiosis – produced by inhaling silica dust particles. It affects workers in hard-rock mining and tunnelling, quarrying, stone dressing, and boiler scaling. Silica stimulates fibrosis of lung tissue, which produces progressive breathlessness and considerably increased susceptibility to tuberculosis.

Back  -    New Search

silver nitrate (sil-ver ny-trayt) n.

a salt of silver with caustic, astringent, and disinfectant properties. It is applied in solutions or creams to destroy warts and to treat skin injuries, including burns. Formula:
AgNO_3
.

Back  -    New Search

simethicone (si-meth-i-kohn) n.

a silicone-based material with antifoaming properties, used in the treatment of flatulence and often incorporated into antacid remedies. Simethicone is also used in barrier creams for the management of napkin rash and other skin disorders.

Back  -    New Search

Simmond's disease (sim-nz) n.

loss of sexual function, loss of weight, and other features of hypopituitarism caused by trauma or tumours or occurring in women after childbirth complicated by bleeding (postpartum haemorrhage). [M. Simmonds (1855–1925), German physician]

Back  -    New Search

Sims's position (simz-iz) n.

the left-sided knees-up position commonly assumed by patients undergoing examinations of the anus and rectum or vagina. [J. M. Sims (1813–83), US gynaecologist]

Back  -    New Search

simvastatin (sim-vas-t-tin) n.

a drug used to reduce abnormally high levels of cholesterol in the blood. Trade name: Zocor .

Back  -    New Search

sinew (sin-yoo) n.

a tendon.

Back  -    New Search

singer's nodule (sing-erz) n.

a pearly white nodule that may develop on the vocal folds of people who use their voice excessively or in those with poor vocal technique.

Back  -    New Search

singultus (sing-gul-ts) n.

see HICCUP.

Back  -    New Search

sinistr- (sinistro-) prefix

denoting left or the left side.

Back  -    New Search

sino- (sinu-) prefix

denoting 1 a sinus.

2 the sinus venosus.
Top

Back  -    New Search

sinoatrial node (SA node) (sy-noh-ay-tri-l) n.

the pacemaker of the heart: a microscopic area of specialized cardiac muscle located in the upper wall of the right atrium near the entry of the vena cava. Fibres of the SA node contract at around 70 times per minute. Following each contraction, the impulse spreads along connecting fibres to the atrioventricular node. Impulses arriving at the SA node accelerate or decrease the heart rate.

Back  -    New Search

sinogram (sy-noh-gram) n.

an X-ray photograph of a sinus that has been injected with a radiopaque substance.
—sinography (sy-nog-rfi) n.

Back  -    New Search

sinus (sy-ns) n.

1 an air cavity within a bone, especially any of the cavities within the bones of the face or skull (see PARANASAL SINUSES).

2 any wide channel containing blood, usually venous blood. s. arrhythmia see ARRHYTHMIA. s. venosus a chamber in the embryonic heart that becomes part of the right atrium after birth.
Top

3 a pocket or bulge in a tubular organ, especially a blood vessel.
Top

4 (sinus tract) an infected tract leading from a focus of infection to the surface of the skin or a hollow organ. See PILONIDAL SINUS.
Top

Back  -    New Search

sinusitis (sy-ns-I-tis) n.

inflammation of one or more of the paranasal sinuses. It is often associated with rhinitis and may be acute or chronic. Symptoms may include pain, purulent discharge from the nose, nasal obstruction, and disturbances of the sense of smell. Persistent cases require treatment with antibiotics, decongestants, or steroid nose drops; surgery, such as sinus washouts or antrostomy, is occasionally required.

Back  -    New Search

sinusoid (sy-new-soid) n.

a small blood vessel found in certain organs, such as the adrenal gland and liver.

Back  -    New Search

siphonage (sy-fn-ij) n.

the transfer of liquid from one container to another by means of a bent tube. The procedure is used in gastric lavage.

Back  -    New Search

sitz bath (sits) n.

a fairly shallow hip bath. Sitz baths of cold and hot water, rapidly alternated, were formerly used for the treatment of a variety of sexual disorders.

Back  -    New Search

SI units (Système International d'Unités) pl. n.

the internationally agreed system of units, based on the metre-kilogram-second system, now in use for all scientific purposes.

TABLE 11.1 Base and supplementary SI units

Physical quantity

Name of unit

Symbol for unit

length

metre

m

mass

kilogram

kg

time

second

s

electric current

ampere

A

thermodynamic temperature

kelvin

K

luminous intensity

candela

cd

amount of substance

mole

mol

plane angle

radian

rad

solid angle

steradian

sr

supplementary units

TABLE 11.2 Derived SI units with special names

Physical quantity

Name of unit

Symbol for unit

frequency

hertz

Hz

energy

joule

J

force

newton

N

power

watt

W

pressure

pascal

Pa

electric charge

coulomb

C

electric potential difference

volt

V

electric resistance

ohm

electric conductance

siemens

S

electric capacitance

farad

F

magnetic flux

weber

Wb

inductance

henry

H

magnetic flux density (magnetic induction)

tesla

T

luminous flux

lumen

lm

illuminance (illumination

lux

lx

absorbed dose

gray

Gy

activity

becquerel

Bq

dose equivalent

sievert

Sv

TABLE 11.3 Decimal multiples and submultiples to be used with SI units

Submultiple

Prefix

Symbol

Multiple

Prefix

Symbol

10-1

deci-

d

10^1

deca-

da

10-2

centi-

c

10^2

hecto-

h

10-3

milli-

m

10^3

kilo-

k

10-6

micro-

µ

10^6

mega-

M

10-9

nano-

n

10^9

giga-

G

10-12

pico-

p

10^12

tera-

T

10-15

femto-

f

10^15

peta-

P

10-18

atto-

a

10^18

exa-

E

10-21

zepto-

z

10^21

zetta-

Z

10-24

yocto-

y

10^24

yotta-

Y

TABLE 11.4 Conversion of units to and from SI units

From

To

Multiply by

in

m

0.025

ft

m

0.3048

sq in

m^2

0.00064516

sq ft

m^2

0.092903

cu in

m^3

0.0000164

cu ft

m^3

0.0283168

l(itre)

m^3

0.001

gal(lon)

m^3

0.0045609

gal(lon)

litres

4.5609

lb

kg

0.453592

g cm-3

kg m-3

1000

lb/in^3

kg m-3

27679.9

mmHg

Pa

133.322

cal

J

4.1868

m

in

39.3701

cm

in

0.393701

cm^2

sq in

0.155

m^2

sq in

1550

m^2

sq ft

10.7639

m^3

cu in

61023.6

m^3

cu ft

35.3146

m^3

l(itre)

1000

m^3

gal(lon)

219.969

kg

lb

2.20462

kg m-3

g cm-3

0.001

kg m-3

lb/in^3

0.0000363

Pa

mmHg

0.0075006

J

cal

0.238846

Temperature conversion

°C (Celsius) = 5/9 (°F - 32)

°F (Fahrenheit) = (9/5 × °C) + 32

Back  -    New Search

Sjögren's syndrome (sher-grenz) n.

an autoimmune condition affecting the salivary and lacrimal glands, resulting in a dry mouth and dryness of the eyes. In the systemic form of the disease other glands may be affected, causing dryness of the airways, vagina, or skin. The syndrome may occur secondarily to other conditions, such as rheumatoid arthritis. [H. S. C. Sjögren (20th century), Swedish ophthalmologist]

Back  -    New Search

skatole (methyl indole) (skat-ohl) n.

a derivative of the amino acid tryptophan, excreted in the urine and faeces.

Back  -    New Search

skeletal muscle (skel-i-t'l) n.

see STRIATED MUSCLE.

Back  -    New Search

skeleton (skel-i-tn) n.

the rigid framework of connected bones that gives form to the body, protects and supports its soft organs and tissues, and provides attachments for muscles and a system of levers essential for locomotion. (See illustration.)

—skeletal adj.

Back  -    New Search

skia- prefix

denoting shadow.

Back  -    New Search

skiagram (sky--gram) n.

an obsolete term for an X-ray photograph.
—skiagraphy (sky-ag-rfi) n.

Back  -    New Search

skier's thumb (gamekeeper's thumb) (skee-erz) n.

rupture and consequent instability of the ligament on the inside of the thumb between the metacarpal and proximal (first) phalanx, caused by forced abduction of the thumb.

Back  -    New Search

skill mix (skil miks) n.

the various skill levels of health-service staff required either within a particular discipline or for the total staff within a health authority.

Back  -    New Search

skin (skin) n.

the outer covering of the body, consisting of an outer layer, the epidermis, and an inner layer, the dermis (see illustration). The epidermis protects the body from injury and from invasion by parasites. It also helps to prevent the body from becoming dehydrated. The combination of erectile hairs, sweat glands, and blood capillaries in the skin form part of the temperature-regulating mechanism of the body. The skin also acts as an organ of excretion (by the secretion of sweat) and as a sense organ (it contains receptors that are sensitive to heat, cold, touch, and pain). Anatomical name: cutis. s. graft a portion of healthy skin cut from one area of the body and used to cover a part that has lost its skin, usually as a result of injury, burns, or operation.

Back  -    New Search

ski-stick injury (skee-stik) n.

a penetrating injury by a ski stick.

Back  -    New Search

skull (skul) n.

the skeleton of the head and face, which is made up of 22 bones. It can be divided into the cranium, which encloses the brain, and the face, including the lower jaw (mandible). (See illustration.) All the bones of the skull except the mandible are connected to each other by immovable joints (see SUTURE). The skull contains cavities for the eyes and nose and a large opening at its base (foramen magnum) through which the spinal cord passes.

Back  -    New Search

SLE n.

systemic lupus erythematosus: see LUPUS (ERYTHEMATOSUS).

Back  -    New Search

sleep (sleep) n.

a state of natural unconsciousness, during which the brain's activity is not apparent (apart from the continued maintenance of basic bodily functions, such as breathing) but can be detected by means of an electroencephalogram (EEG). See also REM.

Back  -    New Search

sleep apnoea n.

cessation of breathing during sleep. central s. a. sleep apnoea in which there is no evidence of any voluntary efforts to breathe. obstructive s. a. sleep apnoea due to frustrated efforts to breathe against blocked upper airways. It is associated with loud snoring and a fall in the oxygen concentration of the blood; patients are typically obese and their tonsils are often enlarged.

Back  -    New Search

sleeping sickness (African trypanosomiasis) (sleep-ing) n.

a disease of tropical Africa caused by the presence in the blood of the parasitic protozoans Trypanosoma gambiense or T. rhodesiense, which are transmitted to man through the bite of tsetse flies. Initial symptoms include fever, headache, and chills, followed later by enlargement of the lymph nodes, anaemia, and pains in the limbs and joints. The parasites eventually invade the minute blood vessels supplying the central nervous system, causing drowsiness and lethargy.

Back  -    New Search

sleep-walking (sleep-wawk-ing) n.

see SOMNAMBULISM.

Back  -    New Search

sling (sling) n.

a bandage arranged to support and rest an injured limb so that healing is not hindered by activity. The most common sling is a triangular bandage tied behind the neck to support the weight of a broken arm.

Back  -    New Search

slipped disc (slipt) n.

see PROLAPSED INTERVERTEBRAL DISC.

Back  -    New Search

slit lamp (slit) n.

a device for providing a narrow beam of light, used in conjunction with a special microscope. It can be used to examine minutely the structures within the eye, one layer at a time.

Back  -    New Search

slough (sluf) n.

dead tissue, such as skin, that separates from healthy tissue after inflammation or infection.

Back  -    New Search

slow virus (sloh) n.

one of a group of infective disease agents that resemble viruses in some of their biological properties but whose physical properties (e.g. sensitivity to radiation) suggest that they may not contain nucleic acid. They are now more commonly known as prions.

Back  -    New Search

SMA n.

see SPINAL MUSCULAR ATROPHY.

Back  -    New Search

small for dates (SFD) (smawl fer dayts) adj.

see INTRAUTERINE (GROWTH RETARDATION).

Back  -    New Search

smallpox (smawl-poks) n.

an acute infectious virus disease causing high fever and a rash that scars the skin. The rash consists of red spots (macules) that appear on the face, spread to the trunk and extremities, and gradually develop into pustules. Most patients recover but serious complications, such as nephritis or pneumonia, may develop. Treatment with thiosemicarbazone is effective. Immunization against smallpox has now totally eradicated the disease. Medical name: variola . See also ALASTRIM, COWPOX.

Back  -    New Search

smear (smeer) n.

a specimen of tissue or other material taken from part of the body and smeared on a microscope slide for examination. See CERVICAL (SMEAR).

Back  -    New Search

smegma (smeg-m) n.

the secretion of the glands of the foreskin (prepuce), which accumulates under the foreskin and has a white cheesy appearance.

Back  -    New Search

Smith-Petersen nail (smith-pee-ter-sn) n.

a stainless steel nail used to fix fragments of bone when the neck of the femur is fractured. [M. N. Smith-Petersen (1886–1953), US orthopaedic surgeon]

Back  -    New Search

Smith's fracture n.

see FRACTURE. [R. W. Smith (1807–73), Irish surgeon]

Back  -    New Search

smooth muscle (involuntary muscle) (smooth) n.

muscle that produces slow long-term contractions of which the individual is unaware. Smooth muscle occurs in hollow organs, such as the stomach, intestine, blood vessels, and bladder. Compare STRIATED MUSCLE.

Back  -    New Search

snare (snair) n.

an instrument consisting of a wire loop designed to remove polyps, tumours, and other projections of tissue. See also DIATHERMY.

Back  -    New Search

sneeze (sneez) n.

1 an involuntary violent reflex expulsion of air through the nose and mouth provoked by irritation of the mucous membrane lining the nasal cavity.

2 vb. to produce a sneeze.
Top

Back  -    New Search

Snellen chart (snel-n) n.

the commonest chart used for testing sharpness of distant vision (see VISUAL ACUITY). It consists of rows of capital letters, called test types , the letters of each row becoming smaller down the chart. [H. Snellen (1834–1908), Dutch ophthalmologist]

Back  -    New Search

snoring (snor-ing) n.

noisy breathing while asleep due to vibration of the soft palate, uvula, pharyngeal walls, or epiglottis.

Back  -    New Search

snow blindness (snoh) n.

a painful disorder of the cornea of the eye due to excessive exposure to ultraviolet light reflected from the snow.

Back  -    New Search

snuffles (snuf-lz) n.

1 partial obstruction of breathing in infants, caused by the common cold.

2 (formerly) discharge through the nostrils associated with necrosis of the nasal bones: seen in infants with congenital syphilis.
Top

Back  -    New Search

socket (sok-it) n.

(in anatomy) a hollow or depression into which another part fits.

Back  -    New Search

sodium (soh-dim) n.

a mineral element and an important constituent of the human body. The amount of sodium in the body is controlled by the kidneys. An excess of sodium leads to the condition of hypernatraemia, which often results in oedema. Sodium is also implicated in hypertension: a high-sodium diet is thought to increase the risk of hypertension in later life. Symbol: Na.

Back  -    New Search

sodium bicarbonate (by-kar-bn-ayt) n.

a salt of sodium that neutralizes acid and is administered by mouth or injection to treat stomach and digestive disorders, acidosis, and sodium deficiency. See also ANTACID.

Back  -    New Search

sodium chloride (klor-ryd) n.

common salt: a salt of sodium that is an important constituent of the body and is used to replace lost fluids and electrolytes and to irrigate body cavities. Formula:
NaCl
.

Back  -    New Search

sodium citrate (sit-rayt) n.

a salt of sodium used to prevent the clotting of stored blood and as a mild diuretic and laxative.

Back  -    New Search

sodium fusidate (few-si-dayt) n.

an antibiotic used mainly to treat infections caused by Staphylococcus. It is administered by mouth or injection or applied in an ointment for skin infections. Trade name: Fucidin .

Back  -    New Search

sodium nitrite (ny-tryt) n.

a sodium salt administered by injection, with sodium thiosulphate, to treat cyanide poisoning. It also has effects similar to glyceryl trinitrate and has been used to treat angina.

Back  -    New Search

sodium salicylate n.

a drug with actions and side-effects similar to those of aspirin. It is used mainly to treat rheumatic fever.

Back  -    New Search

sodium thiosulphate (th'y-oh-sul-fayt) n.

a salt of sodium administered by intravenous injection, with sodium nitrite, to treat cyanide poisoning.

Back  -    New Search

sodium valproate (val-proh-ayt) n.

an anticonvulsant drug administered by mouth to treat all types of epilepsy. Trade name: Epilim .

Back  -    New Search

sodokosis (soh-doh-koh-sis) n.

see RAT-BITE FEVER.

Back  -    New Search

soft sore (chancroid) (soft) n.

a sexually transmitted disease that is caused by the bacterium Haemophilus ducreyi, resulting in enlargement and ulceration of lymph nodes in the groin. Treatment with sulphonamides is effective.

Back  -    New Search

solarium (s-lair-im) n.

a room in which patients are exposed to either sunlight or artificial sunlight (a blend of visible light and infrared and ultraviolet radiation).

Back  -    New Search

solar plexus (coeliac plexus) (soh-ler pleks-s) n.

a network of sympathetic nerves and ganglia high in the back of the abdomen.

Back  -    New Search

soleus (soh-li-s) n.

a broad flat muscle in the calf of the leg. The soleus flexes the foot, so that the toes point downwards.

Back  -    New Search

solution (s-loo-shn) n.

a homogeneous mixture of two or more dissimilar substances, usually of a liquid (the solvent ) in which a solid (the solute ) is dissolved.

Back  -    New Search

solvent (sol-vnt) n.

see SOLUTION.

Back  -    New Search

soma (soh-m) n.

1 the entire body excluding the germ cells.

2 the body as distinct from the mind.
Top

Back  -    New Search

somat- prefix

denoting 1 the body.

2 somatic.
Top

Back  -    New Search

somatic (s-mat-ik) adj.

1 relating to the nonreproductive parts of the body.

2 relating to the body wall (i.e. excluding the viscera). Compare SPLANCHNIC.
Top

3 relating to the body rather than the mind.
Top

Back  -    New Search

somatization disorder (Briquet's syndrome) (soh-m-ty-zay-shn) n.

a psychiatric disorder that is characterized by multiple recurrent changing physical symptoms in the absence of physical disorders that could explain them.

Back  -    New Search

somatoform disorders (s-mat-oh-form) pl. n.

a group of disorders in which there is a history of repeated physical complaints with no physical basis. They include somatization disorder and hypochondriasis.

Back  -    New Search

somatostatin (growth-hormone-release inhibiting factor) (soh-m-toh-stay-tin) n.

a hormone, produced by the hypothalamus and some extraneural tissues, including the gastro-intestinal tract and the pancreas (see ISLETS OF LANGERHANS), that inhibits growth hormone (somatotrophin) release by the pituitary gland.

Back  -    New Search

somatotrophin (soh-m-toh-troh-fin) n.

see GROWTH HORMONE.

Back  -    New Search

somnambulism (noctambulation) (som-nam-bew-lizm) n.

sleep-walking: walking about and performing other actions in a semiautomatic way during sleep without later memory of doing so. It is common during childhood and can also arise as the result of stress or hypnosis.
—somnambulistic adj.

Back  -    New Search

somnolism (som-noh-lizm) n.

a hypnotic trance. See HYPNOSIS.

Back  -    New Search

Sonne dysentery (sonn-i) n.

bacillary dysentery caused by the species Shigella sonnei. [C. Sonne (1882–1948), Danish bacteriologist]

Back  -    New Search

sonography (sonn-og-rfi) n.

see ULTRASONOGRAPHY.

Back  -    New Search

sonoplacentography (soh-noh-plas-en-tog-rfi) n.

the technique of using ultrasound waves to determine the position of the placenta during pregnancy.

Back  -    New Search

soporific (sop-er-if-ik) n.

see HYPNOTIC.

Back  -    New Search

sorbitol (sor-bit-ol) n.

a carbohydrate with a sweet taste, used by diabetics as a substitute for cane sugar. It is also administered by mouth or injection in disorders of carbohydrate metabolism and in drip feeding.

Back  -    New Search

sordes (sor-deez) pl. n.

the brownish encrustations that form around the mouth and teeth of patients suffering from fevers.

Back  -    New Search

sore (sor) n.

a lay term for any ulcer or other open wound of the skin or mucous membranes. See also BEDSORE, SOFT SORE.

Back  -    New Search

sore throat n.

pain at the back of the mouth, commonly due to tonsillitis or pharyngitis. If infection persists the lymph nodes in the neck may become tender and enlarged (cervical adenitis).

Back  -    New Search

sotalol (soh-t-lol) n.

a drug (see BETA BLOCKER) administered by mouth or injection to treat abnormal heart rhythm, angina, and high blood pressure and to relieve symptoms in thyrotoxicosis. Trade names: Beta-Cardone , Sotacor .

Back  -    New Search

souffle (soo-fl) n.

a soft blowing sound heard through the stethoscope, usually produced by blood flowing in vessels.

Back  -    New Search

sound (sownd) (in surgery)

1 n. a long rodlike instrument, often with a curved end, used to explore body cavities or to dilate strictures in the urethra or other canals.

2 vb. to explore a cavity using a sound.
Top

Back  -    New Search

Southey's tubes (suth-iz) pl. n.

fine-calibre tubes for insertion into subcutaneous tissue to drain excess fluid. They are rarely used in practice today. [R. Southey (1835–99), British physician]

Back  -    New Search

Spanish fly (span-ish) n.

the blister beetle, Lytta vesicatoria: source of the irritant and toxic chemical compound cantharidin.

Back  -    New Search

spansule (span-sewl) n.

a drug in the form of a capsule prepared in such a way that, when taken orally, its contents are released slowly.

Back  -    New Search

spasm (spazm) n.

a sustained involuntary muscular contraction, which may occur either as part of a generalized disorder or as a local response to an otherwise unconnected painful condition. carpopedal s. a spasm that affects the muscles of the hands and feet and is caused by a reduction in the blood calcium level (often transitory), as in hyperventilation.

Back  -    New Search

spasmo- prefix

denoting spasm.

Back  -    New Search

spasmodic (spaz-mod-ik) adj.

occurring in spasms or resembling a spasm.

Back  -    New Search

spasmolytic (spaz-moh-lit-ik) n.

a drug that relieves spasm of smooth muscle, e.g. aminophylline or papaverine. Spasmolytics may be used as bronchodilators to stimulate the heart in the treatment of angina, or to relieve colic.

Back  -    New Search

spasmus nutans (spaz-ms new-tanz) n.

a combination of symptoms including a slow nodding movement of the head, nystagmus, and spasm of the neck muscles. It affects infants and it normally disappears within a year or two.

Back  -    New Search

spastic (spast-ik)

1 adj. characterized by spasms. s. colon see IRRITABLE BOWEL SYNDROME. s. paralysis weakness of a limb or limbs associated with increased reflex activity. This results in spasticity and is caused by disease affecting the nerve fibres of the corticospinal tract. See CEREBRAL PALSY.

2 n. an individual suffering from spastic paralysis.
Top

Back  -    New Search

spasticity (spas-tis-iti) n.

resistance to the passive movement of a limb that is maximal at the beginning of the movement and gives way as more pressure is applied. It is a symptom of damage to the corticospinal tracts in the brain or spinal cord. Compare RIGIDITY.

Back  -    New Search

spatula (spat-yoo-l) n.

an instrument with a blunt blade used to spread ointments or plasters and, particularly in dentistry, to mix materials. A flat spatula is used to depress the tongue during examination of the oropharynx.

Back  -    New Search

special hospital (spesh-l) n.

a hospital for the care of mentally ill patients who are also dangerous and must therefore be kept securely.

Back  -    New Search

special school n.

(in Britain) an education establishment for disabled children.

Back  -    New Search

species (spee-shiz) n.

the smallest unit used in the classification of living organisms. Members of the same species are able to interbreed and to produce fertile offspring. Similar species are grouped together within one genus.

Back  -    New Search

specific (spi-sif-ik)

1 n. a medicine that has properties especially useful for the treatment of a particular disease.

2 adj. (of a disease) caused by a particular microorganism that causes no other disease.
Top

3 adj. of or relating to a species.
Top

Back  -    New Search

specific gravity (grav-iti) n.

see RELATIVE DENSITY.

Back  -    New Search

spectinomycin (spek-tin-oh-my-sin) n.

an antibiotic administered by injection to treat various infections, particularly gonorrhoea. Trade name: Trobicin .

Back  -    New Search

spectroscope (spek-tr-skohp) n.

an instrument that is used to split up light or other radiation into components of different wavelengths. The simplest spectroscope uses a prism, which splits white light into the rainbow colours of the visible spectrum.

Back  -    New Search

spectrum (spek-trm) n.

(in pharmacology) the range of effectiveness of an antibiotic. broad s. effectiveness against a wide range of microoganisms.

Back  -    New Search

speculum (spek-yoo-lm) n. (pl. specula)

a metal instrument for inserting into and holding open a cavity of the body, such as the vagina, rectum, or nasal orifice, in order that the interior may be examined.

Back  -    New Search

speech therapy (speech) n.

the rehabilitation of patients who are unable to speak coherently because of congenital causes, accidents, or illness. Speech therapists have special training in this field but are not medically registered.

Back  -    New Search

sperm (sperm) n.

see SPERMATOZOON.

Back  -    New Search

sperm- (spermi(o)- spermo-) prefix

denoting sperm or semen.

Back  -    New Search

spermat- (spermato-) prefix

denoting 1 sperm.

2 organs or ducts associated with sperm.
Top

Back  -    New Search

spermatic artery (sper-mat-ik) n.

either of two arteries that originate from the abdominal aorta and travel downwards to supply the testes.

Back  -    New Search

spermatic cord n.

the cord, consisting of the vas deferens, nerves, and blood vessels, that runs from the abdominal cavity to the testicle in the scrotum.

Back  -    New Search

spermatocele (sperm--toh-seel) n.

a cystic swelling in the scrotum containing sperm. The cyst arises from the epididymis and can be felt as a lump above the testis. Treatment is by surgical removal.

Back  -    New Search

spermatogenesis (sperm--toh-jen-i-sis) n.

the process by which mature spermatozoa are produced in the testis.
Spermatogonia, in the outermost layer of the seminiferous tubules, multiply throughout reproductive life. Some of them divide by meiosis into spermatocytes, which produce haploid spermatids.
These are transformed into mature spermatozoa by the process of spermiogenesis . The whole process takes 70–80 days.

Back  -    New Search

spermatorrhoea (sperm--t-ree-) n.

the involuntary discharge of semen without orgasm.

Back  -    New Search

spermatozoon (sperm) (sperm--toh-zoh-n) n. (pl. spermatozoa)

a mature male sex cell (see GAMETE). The tail of a sperm enables it to swim, which is important as a means for reaching and fertilizing the ovum. (See illustration.) See also ACROSOME, FERTILIZATION.

Back  -    New Search

spermaturia (sperm-t-yoor-i) n.

the presence of spermatozoa in the urine. Abnormal ejaculation into the bladder on orgasm (retrograde ejaculation) may occur after prostatectomy or other surgical procedures or in certain neurological conditions.

Back  -    New Search

sperm count n.

an estimate of the total number of spermatozoa in a specimen of ejaculated semen, which is used as a measure of male fertility. Normal values for sperm concentration are 20–200 million spermatozoa per ml ejaculate. See also SEMINAL ANALYSIS.

Back  -    New Search

spermicide (sperm-i-syd) n.

an agent that kills spermatozoa. Contraceptive creams and jellies contain chemical spermicides.
—spermicidal adj.

Back  -    New Search

spermiogenesis (sperm-i-oh-jen-i-sis) n.

see SPERMATOGENESIS.

Back  -    New Search

spheno- prefix

denoting the sphenoid bone.

Back  -    New Search

sphenoid bone (sfee-noid) n.

a bone forming the base of the cranium behind the eyes. See SKULL.

Back  -    New Search

spherocyte (sfeer-oh-syt) n.

an abnormal form of red blood cell (erythrocyte) that is spherical rather than disc-shaped. They are characteristic of some forms of haemolytic anaemia. Spherocytes tend to be removed from the blood as they pass through the spleen. See also SPHEROCYTOSIS.

Back  -    New Search

spherocytosis (sfeer-oh-sy-toh-sis) n.

the presence in the blood of spherocytes. Spherocytosis may occur as a hereditary disorder (hereditary s. ) or in certain haemolytic anaemias.

Back  -    New Search

sphincter (sfink-ter) n.

a specialized ring of muscle that surrounds an orifice. Contractions of the sphincter partly or completely close the orifice. Sphincters are found, for example, around the anus (anal s. ) and at the opening between the stomach and duodenum (pyloric s. ).

Back  -    New Search

sphincter- prefix

denoting a sphincter.

Back  -    New Search

sphincterectomy (sfink-ter-ek-tmi) n.

the surgical division, usually partial, of any sphincter muscle.

Back  -    New Search

sphincterotomy (sfink-ter-ot-mi) n.

1 surgical division of any sphincter muscle.

2 surgical removal of part of the iris in the eye at the border of the pupil.
Top

Back  -    New Search

sphygmo- prefix

denoting the pulse.

Back  -    New Search

sphygmocardiograph (sfig-moh-kar-di--grahf) n.

an apparatus for producing a continuous record of both the heartbeat and the subsequent pulse in one of the blood vessels. The recording can be shown on a moving tape or on an electronic screen.

Back  -    New Search

sphygmograph (sfig-moh-grahf) n.

an apparatus for producing a continuous record of the pulse in one of the blood vessels, showing the strength and rate of the beats.

Back  -    New Search

sphygmomanometer (sfig-moh-m-nom-it-er) n.

an instrument for measuring blood pressure in the arteries. It consists of an inflatable cuff connected via a rubber tube to a column of mercury with a graduated scale.

Back  -    New Search

spica (spy-k) n.

a bandage wound repeatedly in a figure-of-eight around an injured limb, forming a series of V-shapes. See illustration.

Back  -    New Search

spicule (spik-yool) n.

a small splinter of bone.

Back  -    New Search

spigot (spig-t) n.

a glass or plastic peg used to close the opening of a tube, used in nasogastric tubes and catheters.

Back  -    New Search

spina bifida (rachischisis) (spy-n bif-id-) n.

a developmental defect in which the newborn baby has part of the spinal cord and its coverings exposed through a gap in the backbone (see NEURAL TUBE DEFECTS). The symptoms may include paralysis of the legs, incontinence, and mental retardation from the commonly associated brain defect, hydrocephalus. Spina bifida can be diagnosed at about the 16th week of pregnancy by a maternal blood test and confirmed by amniocentesis and ultrasound. s. b. occulta a defect in the bony arch of the spine that (unlike spina bifida) has a normal skin covering; there may be an overlying hairy patch. It is not associated with neurological involvement.

Back  -    New Search

spinal accessory nerve (spy-nl) n.

see ACCESSORY NERVE.

Back  -    New Search

spinal anaesthesia n.

1 suppression of sensation, usually in the lower part of the body, by the injection of a local anaesthetic into the spaces surrounding the spinal cord. Spinal anaesthesia is useful in patients whose condition makes them unsuitable for a general anaesthetic, for certain obstetric procedures, to reduce the requirements for general anaesthetic drugs, or in circumstances where a skilled anaesthetist is not available. epidural s. a. spinal anaesthesia in which the anaesthetic is injected between the dura and the surrounding bony vertebral foramen, using a special blunt needle with a side-hole to reduce the chance of penetrating the dura.

2 loss of sensation in part of the body as a result of injury or disease to the spinal cord.
Top

Back  -    New Search

spinal column

n. see BACKBONE.

Back  -    New Search

spinal cord

n. the portion of the central nervous system enclosed in the vertebral column, consisting of nerve cells and bundles of nerves connecting all parts of the body with the brain. It extends from the medulla oblongata in the skull to the level of the second lumbar vertebra.

Back  -    New Search

spinal muscular atrophy (SMA) n.

a hereditary condition in which cells of the spinal cord die and the muscles in the arms and legs become progressively weaker. It usually develops between the ages of 2 and 12; eventually the respiratory muscles are affected and death usually results from respiratory infection. infantile s. m. a. an acute aggressive form of the condition (see. WERDNIG-HOFFMANN DISEASE).

Back  -    New Search

spinal nerves

pl. n. the 31 pairs of nerves that leave the spinal cord and are distributed to the body, passing out from the vertebral canal through the spaces between the arches of the vertebrae.

Back  -    New Search

spinal shock

n. a state of shock accompanied by temporary paralysis of the lower extremities that results from injury to the spine and is often associated with ileus. If the spinal cord is transected, permanent motor paralysis persists below the level of spinal-cord division.

Back  -    New Search

spindle (spin-d'l) n.

a collection of fibres seen in a cell when it is dividing. It plays an important part in chromosome movement in mitosis and meiosis and is also involved in division of the cytoplasm.

Back  -    New Search

spine (spyn) n.

1 a sharp process on a bone.

2 the vertebral column (see BACKBONE).
Top

—spinal adj.

Back  -    New Search

spino- prefix

denoting 1 the spine.

2 the spinal cord.
Top

Back  -    New Search

spiral bandage (spyr-l) n.

a bandage wound round a part of the body, overlapping the previous section at each turn.

Back  -    New Search

spiral organ

n. see ORGAN (OF CORTI).

Back  -    New Search

Spirillum (spy-ril-m) n.

a genus of highly motile rigid spiral-shaped bacteria usually found in fresh and salt water containing organic matter. S. minus a species that causes rat-bite fever.

Back  -    New Search

spiro- prefix

denoting 1 spiral.

2 respiration.
Top

Back  -    New Search

spirochaetaemia (spy-roh-ki-tee-mi) n.

the presence of spirochaetes in the bloodstream, occurring in the later stages of syphilis.

Back  -    New Search

spirochaete (spy-roh-keet) n.

any one of a group of spiral-shaped bacteria that lack a rigid cell wall and move by means of muscular flexions of the cell. The group includes Borrelia, Leptospira, and Treponema.

Back  -    New Search

spirograph (spy-roh-grahf) n.

an instrument for recording breathing movements. The record obtained is called a spirogram .
—spirography n.

Back  -    New Search

spirometer (spy-rom-it-er) n.

an instrument for measuring the volume of air inhaled and exhaled. It is used in tests of ventilation.
—spirometry n.

Back  -    New Search

spironolactone (spy-r-noh-lak-tohn) n.

a synthetic corticosteroid that inhibits the activity of the hormone aldosterone and is administered by mouth as a potassium-sparing diuretic to treat heart failure, high blood pressure, and fluid retention (oedema). Trade name: Aldactone .

Back  -    New Search

Spitz-Holter valve (spits-hohl-ter) n.

a valve used in the treatment of hydrocephalus to drain cerebrospinal fluid from the ventricles of the brain into either the right atrium or the peritoneum.

Back  -    New Search

splanch- (splanchno-) prefix

denoting the viscera.

Back  -    New Search

splanchnic (splank-nik) adj.

relating to the viscera. Compare SOMATIC. s. nerves the series of nerves in the sympathetic system that are distributed to the blood vessels and viscera.

Back  -    New Search

splanchnology (splank-nol-ji) n.

the study of the viscera.

Back  -    New Search

spleen (spleen) n.

a large dark-red ovoid organ situated on the left side of the body below and behind the stomach. The spongy interior (pulp ) of the spleen consists of lymphoid tissue within a meshwork of reticular fibres. The spleen is a major component of the reticuloendothelial system, producing lymphocytes in the newborn and containing phagocytes, which remove worn-out red blood cells and other foreign bodies from the bloodstream. Anatomical name: lien .
—splenic (splen-ik) adj.

Back  -    New Search

splen- (spleno-) prefix

denoting the spleen.

Back  -    New Search

splenectomy (spli-nek-tmi) n.

surgical removal of the spleen. This is sometimes necessary in the emergency treatment of bleeding from a ruptured spleen.

Back  -    New Search

splenic anaemia

n. anaemia associated with portal hypertension and increased destruction of red blood cells by an overactive spleen.

Back  -    New Search

splenitis (spli-ny-tis) n.

inflammation of the spleen. See also PERISPLENITIS.

Back  -    New Search

splenomegaly (splee-noh-meg-li) n.

enlargement of the spleen. It commonly occurs in malaria, blood disorders, leukaemia, and Hodgkin's disease. See also HYPERSPLENISM.

Back  -    New Search

splenorenal anastomosis (splee-noh-ree-nl) n.

a method of treating portal hypertension by joining the splenic vein to the left renal vein. Compare PORTACAVAL ANASTOMOSIS.

Back  -    New Search

splenovenography (splee-noh-vi-nog-rfi) n.

X-ray examination of the spleen and veins associated with it following injection of a radiopaque dye.

Back  -    New Search

splint (splint) n.

a rigid support to hold broken bones in position until healing has occurred.

Back  -    New Search

splinter haemorrhage (splint-er) n.

a linear haemorrhage below the nails, usually the result of trauma but also occurring in such conditions as subacute bacterial endocarditis or severe rheumatoid arthritis.

Back  -    New Search

spondyl- (spondylo-) prefix

denoting a vertebra or the spine.

Back  -    New Search

spondylitis (spon-di-ly-tis) n.

inflammation of the synovial joints of the backbone. ankylosing s. a type of arthritis that predominantly affects young males. The inflammation affects the joint capsules and their attached ligaments and tendons, principally the intervertebral joints and sacroiliac joints (see SACROILIITIS). The resultant pain and stiffness are treated by analgesics and regular daily exercises. The disorder can lead to severe deformities of the spine (see KYPHOSIS, ANKYLOSIS).

Back  -    New Search

spondylolisthesis (spon-di-loh-lis-thi-sis) n.

a forward shift of one vertebra upon another, due to a defect in the bone or in the joints that normally bind them together. This may be congenital or develop after injury.

Back  -    New Search

spondylosis (spon-di-loh-sis) n.

a spinal condition resulting from degeneration of the intervertebral discs in the cervical, thoracic, or lumbar regions. Symptoms include pain and restriction of movement. Pain is relieved by wearing a collar (when the neck region is affected) or a surgical belt (for the lower spine), which prevents movement. Very severe cases sometimes require surgical fusion.

Back  -    New Search

spondylosyndesis (spon-di-loh-sin-di-sis) n.

surgical fusion of the intervertebral joints of the backbone.

Back  -    New Search

spongiform encephalopathy (spunji-form) n.

any one of a group of rapidly progressive degenerative neurological diseases that include scrapie in sheep, bovine spongiform encephalopathy (BSE) in cattle, and Creutzfeldt-Jakob disease in humans. Human spongiform encephalopathies are characterized by rapidly progressive dementia associated with myoclonic jerks (see MYOCLONUS). The diseases are thought to be caused by abnormal transmissible proteins (see PRION).

Back  -    New Search

spongioblastoma (spunji-oh-blas-toh-m) n.

see GLIOBLASTOMA.

Back  -    New Search

spontaneous (spon-tay-nis) adj.

arising without apparent cause or outside aid. The term is applied in medicine to certain conditions, such as pathological fractures, that arise in the absence of outside injury.

Back  -    New Search

sporadic (sper-ad-ik) adj.

describing a disease that occurs only occasionally or in a few isolated places. Compare ENDEMIC, EPIDEMIC.

Back  -    New Search

spore (spor) n.

a small reproductive body produced by plants and microorganisms. Some kinds of spores function as dormant stages of the life cycle, enabling the organism to survive adverse conditions. Other spores are the means by which the organism can spread vegetatively. See also ENDOSPORE.

Back  -    New Search

sporicide (spor-i-syd) n.

an agent that kills spores (e.g. bacterial spores). Most germicides are ineffective since spores are very resistant to chemical action.
—sporicidal adj.

Back  -    New Search

sporotrichosis (spor-oh-trik-oh-sis) n.

a chronic infection of the skin and superficial lymph nodes that is caused by the fungus Sporothrix schenckii and results in the formation of abscesses and ulcers. It occurs mainly in the tropics.

Back  -    New Search

Sporozoa (spor--zoh-) n.

a group of parasitic protozoa that includes Plasmodium, the malaria parasite.

Back  -    New Search

sports injury (sports in-jeri) n.

any injury related to the practice of a sport, often resulting from the overuse and stretching of muscles, tendons, and ligaments.

Back  -    New Search

sports medicine

n. a specialty concerned with the treatment of sports injuries and measures designed to prevent or minimize them.

Back  -    New Search

spotted fever (spot-id) n.

see MENINGITIS, ROCKY MOUNTAIN SPOTTED FEVER, TYPHUS.

Back  -    New Search

sprain (sprayn) n.

injury to a ligament, caused by sudden overstretching. Sprains should be treated by cold compresses (icepacks) at the time of injury, and later by restriction of activity.

Back  -    New Search

Sprengel's deformity (spreng-lz) n.

a congenital abnormality of the scapula, which is small and positioned high in the shoulder. [O. G. K. Sprengel (1852–1915), German surgeon]

Back  -    New Search

sprue (psilosis) (sproo) n.

deficient absorption of food due to disease of the small intestine. tropical s. sprue that is characterized by diarrhoea (usually steatorrhoea), glossitis, anaemia, and weight loss; the lining of the small intestine is inflamed and atrophied. Treatment with antibiotics and folic acid is usually effective. See also COELIAC DISEASE (NONTROPICAL SPRUE), MALABSORPTION.

Back  -    New Search

spud (spud) n.

a blunt needle used for removing foreign bodies embedded in the cornea of the eye.

Back  -    New Search

spur (sper) n.

a sharp projection, especially one of bone.

Back  -    New Search

sputum (spew-tm) n.

material coughed up from the respiratory tract. Its colour, consistency, and other characteristics often provide important information affecting the diagnosis and the management of respiratory disease. Pathological examination of sputum for microorganisms and abnormal cells may add further information.

Back  -    New Search

squama (skway-m) n. (pl. squamae)

1 a thin plate of bone.

2 a scale, such as any of the scales from the cornified layer of the epidermis.
Top

—squamous adj.

Back  -    New Search

squamo- prefix

denoting 1 the squamous portion of the temporal bone.

2 squamous epithelium.
Top

Back  -    New Search

squamous bone (skway-ms) n.

see TEMPORAL (BONE).

Back  -    New Search

squamous cell carcinoma (SCC) n.

the second commonest form of skin cancer (after basal cell carcinoma), occurring usually in late-middle and old age. Sunlight is the commonest cause: SCC is mainly found on areas exposed to light and is more common in men than in women. It spreads locally at first but later may spread to sites distant from its origin (see METASTASIS). Treatment is usually by surgical excision or radiotherapy.

Back  -    New Search

squamous epithelium n.

see EPITHELIUM.

Back  -    New Search

squint (skwint) n.

see STRABISMUS.

Back  -    New Search

SSPE n.

see SUBACUTE SCLEROSING PANENCEPHALITIS.

Back  -    New Search

SSRI (selective serotonin reuptake inhibitor) n.

any one of a group of antidepressant drugs that exert their action by blocking the reabsorption of the neurotransmitter serotonin by the nerve endings in the brain. Their effect is to increase levels of serotonin in the brain. The group includes citolapram, fluoxetine, fluvoxamine, paroxetine, and sertraline. Side-effects include agitation and nausea.

Back  -    New Search

staccato speech (st-kah-toh) n.

abnormal speech in which there are pauses between words, sometimes associated with multiple sclerosis.

Back  -    New Search

Stacke's operation (stak-z) n.

an operation in which the bone between the mastoid cells and the middle ear is removed to create a single cavity. It is performed when there is chronic infection of this area. [L. Stacke (1859–1918), German otologist]

Back  -    New Search

stadium (stay-dim) n. (pl. stadia)

a stage in the course of a disease. s. invasionis the period between exposure to infection and the onset of symptoms.

Back  -    New Search

stage (stayj) vb.

(in oncology) to classify a primary tumour, by its size and the presence and site of metastases, in order to plan treatment. In addition to clinical examination, a variety of imaging and surgical techniques provide a more accurate assessment.

Back  -    New Search

staghorn calculus (stag-horn) n.

a branched stone forming a cast of the collecting system of the kidney and therefore filling and obstructing the calyces and pelvis. It is usually associated with infection and can cause pyonephrosis and, if neglected, a perinephric abscess.

Back  -    New Search

stagnant loop syndrome (stag-nnt) n.

see BLIND LOOP SYNDROME.

Back  -    New Search

stain (stayn)

1 n. a dye used to colour tissues and other specimens for microscopical examination.

2 vb. to treat a specimen for microscopical study with a stain.
Top

Back  -    New Search

Stamey procedure (stay-mee) n.

an operation devised to cure stress incontinence of urine in women in which the neck of the bladder is stitched to the anterior abdominal wall with unabsorbable suture material. See also COLPOSUSPENSION. [T. A. Stamey , US surgeon]

Back  -    New Search

stammering (stuttering) (stam-er-ing) n.

halting articulation with interruptions to the normal flow of speech and repetition of the initial consonants of words or syllables (compare CLUTTERING). The symptoms are most severe when the stammerer is under any psychological stress. Medical name: dysphemia .
—stammerer n.

Back  -    New Search

stanozolol (stan-oz--lol) n.

an anabolic steroid used to treat the effects of deep vein thrombosis and systemic sclerosis. Trade name: Stromba .

Back  -    New Search

St Anthony's fire (snt ant--niz fyr) n.

an old colloquial name for the inflammation of the skin associated with ergot poisoning. See ERGOTISM.

Back  -    New Search

stapedectomy (stay-pi-dek-tmi) n.

surgical removal of the stapes, enabling it to be replaced with a prosthetic bone in the treatment of otosclerosis.

Back  -    New Search

stapediolysis (st-pee-di-ol-i-sis) n.

an operation to restore hearing in cases of otosclerosis, in which the stapes is freed from the fenestra ovalis.

Back  -    New Search

stapes (stay-peez) n.

a stirrup-shaped bone in the middle ear that articulates with the incus and is attached to the membrane of the fenestra ovalis. See OSSICLE.

Back  -    New Search

staphylectomy (staf-i-lek-tmi) n.

surgical removal of the uvula.

Back  -    New Search

staphylococcal scalded skin syndrome (Lyell's disease, Ritter's disease) (staf-i-loh-kok-k'l skawl-did) n.

a potentially serious condition of young infants in which the skin becomes reddened and then peels off. The underlying cause is a staphylococcal infection. Medical name: toxic epidermal necrolysis .

Back  -    New Search

Staphylococcus (staf-i-loh-kok-s) n.

a genus of Gram-positive nonmotile spherical bacteria occurring in grapelike clusters. Some species are saprophytes; others parasites. Many species produce exotoxins. More serious infections that are caused by staphylococci include pneumonia, bacteraemia, osteomyelitis, and enterocolitis. S. aureus a species that causes boils and internal abscesses.
—staphylococcal adj.

Back  -    New Search

staphyloma (staf-i-loh-m) n.

abnormal bulging of the cornea or sclera (white) of the eye.

Back  -    New Search

staphylorrhaphy (palatorrhaphy) (staf-il-o-rfi) n.

surgical suture of a cleft palate.

Back  -    New Search

staple (stay-pl) n.

(in surgery) a piece of metal used to join up pieces of tissue. Staples can be used as an alternative to sutures for an anastomosis; stapling machines have been produced for this purpose. See also ENDOSTAPLER.

Back  -    New Search

starch (starch) n.

the form in which carbohydrates are stored in many plants and a major constituent of the diet. Starch consists of linked glucose units and occurs in two forms, -amylose and amylopectin . Starch is digested by means of the enzyme amylase. See also DEXTRIN.

Back  -    New Search

startle reflex (star-t'l) n.

see MORO REFLEX.

Back  -    New Search

starvation (star-vay-shn) n.

see MALNUTRITION.

Back  -    New Search

stasis (stay-sis) n.

stagnation or cessation of flow; for example, of blood or lymph whose flow is obstructed or of the intestinal contents when peristalsis is hindered.

Back  -    New Search

-stasis suffix

denoting stoppage of a flow of liquid; stagnation.

Back  -    New Search

status asthmaticus (stay-ts ass-mat-ik-s) n.

a severe attack of asthma. Patients are very breathless and may die from respiratory failure if not treated with inhaled oxygen, bronchodilators, and corticosteroid therapy; sedatives are absolutely contraindicated.

Back  -    New Search

status epilepticus (epi-lep-tik-s) n.

the occurrence of repeated epileptic seizures without any recovery of consciousness between them. Prolonged status epilepticus may lead to the patient's death or long-term disability.

Back  -    New Search

status lymphaticus (lim-fat-ik-s) n.

enlargement of the thymus gland and other parts of the lymphatic system, formerly believed to be a predisposing cause to sudden death in infancy and childhood.

Back  -    New Search

STD n.

see SEXUALLY TRANSMITTED DISEASE.

Back  -    New Search

steapsin (sti-ap-sin) n.

see LIPASE.

Back  -    New Search

stearic acid (sti-a-rik) n.

see FATTY ACID.

Back  -    New Search

steat- (steato-) prefix

denoting fat; fatty tissue.

Back  -    New Search

steatoma (sti--toh-m) n.

any cyst or tumour of a sebaceous gland.

Back  -    New Search

steatopygia (sti--toh-pij-i) n.

the accumulation of large quantities of fat in the buttocks.

Back  -    New Search

steatorrhoea (sti--t-ree-) n.

the passage of abnormally increased amounts of fat in the faeces due to reduced absorption of fat by the intestine (see MALABSORPTION). The faeces are pale and may look greasy.

Back  -    New Search

steatosis (sti--toh-sis) n.

infiltration of hepatocytes with fat. This may occur in pregnancy, alcoholism, malnutrition, obesity, hepatitis C infection, or with some drugs.

Back  -    New Search

Stein-Leventhal syndrome (styn-lev-n-thal) n.

secondary amenorrhoea and sterility associated with multiple cysts in both ovaries. [I. F. Stein (20th century) and M. L. Leventhal (1901–71), US gynaecologists]

Back  -    New Search

Steinmann's pin (styn-manz) n.

a fine metal nail inserted through a fractured bone through which extension is applied to the distal bone fragment. [F. Steinmann (1872–1932), Swiss surgeon]

Back  -    New Search

stellate (stel-ayt) adj.

star-shaped. s. fracture a star-shaped fracture of the kneecap caused by a direct blow. s. ganglion a star-shaped collection of sympathetic nerve cell bodies in the root of the neck.

Back  -    New Search

Stellwag's sign (stel-vagz) n.

apparent widening of the distance between the upper and lower eyelids due to retraction of the upper lid and protrusion of the eyeball. It is a sign of exophthalmic goitre. [C. Stellwag von Carion (1823–1904), Austrian ophthalmologist]

Back  -    New Search

stem cell (stem) n.

an immortal cell that is able to produce all the cells within an organ. haemopoietic s. c. a cell of the bone marrow from which all blood cells are derived.

Back  -    New Search

steno- prefix

denoting 1 narrow.

2 constricted.
Top

Back  -    New Search

stenosis (sti-noh-sis) n.

the abnormal narrowing of a passage or opening, such as a blood vessel or heart valve. See AORTIC STENOSIS, CAROTID-ARTERY STENOSIS, MITRAL STENOSIS, PULMONARY STENOSIS, PYLORIC STENOSIS.

Back  -    New Search

stenostomia (stenostomy) (sten--stoh-mi) n.

the abnormal narrowing of an opening, such as the opening of the bile duct.

Back  -    New Search

Stensen's duct (sten-snz) n.

the long secretory duct of the parotid salivary gland. [N. Stensen (1638–86), Danish physician]

Back  -    New Search

stent (stent) n.

a splint placed inside a duct or canal, such as the ureter, urethra, oesophagus, or bile duct, or an artery. It may be used to aid healing of an anastomosis or placed across an obstruction to maintain an open lumen or in an artery after angioplasty to prevent restenosis.

Back  -    New Search

sterco- prefix

denoting faeces.

Back  -    New Search

stercobilin (ster-koh-by-lin) n.

a brownish-red pigment formed during the metabolism of the bile pigments biliverdin and bilirubin and subsequently excreted in the urine or faeces.

Back  -    New Search

stercolith (ster-koh-lith) n.

a stone formed of dried compressed faeces.

Back  -    New Search

stercoraceous (ster-ker-ay-shs) adj.

composed of or containing faeces.

Back  -    New Search

stereognosis (ste-ri-og-noh-sis) n.

the ability to recognize the three-dimensional shape of an object by touch alone. This is a function of the association areas of the parietal lobe of the brain. See also AGNOSIA.

Back  -    New Search

stereopsis (ste-ri-op-sis) n.

see STEREOSCOPIC VISION.

Back  -    New Search

stereoscopic vision (stereopsis) (ste-ri--skop-ik) n.

perception of the shape, depth, and distance of an object as a result of having binocular vision.

Back  -    New Search

stereotactic (ste-ri--tak-tik) adj.

of or relating to the accurate localization of structures within the body by using three-dimensional measurements. Stereotactic localization enables the accurate positioning within the body of radiotherapy beams or sources for the treatment of tumours and of localizing wires for the biopsy of small tumours. s. surgery see STEREOTAXY.

Back  -    New Search

stereotaxy (stereotactic surgery) (ste-ri--taks-i) n.

a surgical procedure in which a deep-seated area in the brain is operated upon after its position has been accurately established by three-dimensional measurements. The operation may be performed using an electrical current or by heat, cold, or mechanical techniques. See also LEUCOTOMY.

Back  -    New Search

stereotypy (ste-ri--ty-pi) n.

the constant repetition of a complex action, which is carried out in the same way each time. It is seen in catatonia and infantile autism; sometimes it is an isolated symptom in mental retardation.

Back  -    New Search

sterile (ste-ryl) adj.

1 (of a living organism) barren; unable to reproduce its kind (see STERILITY).

2 (of inanimate objects) completely free from microorganisms that could cause infection.
Top

Back  -    New Search

sterility (ster-il-iti) n.

inability to have children, either due to infertility or (in someone who has been fertile) deliberately induced by surgical procedures as a means of contraception (see STERILIZATION).

Back  -    New Search

sterilization (ste-ri-ly-zay-shn) n.

1 a surgical operation or any other process that induces sterility in men or women. In women this is now usually achieved by tubal occlusion : the permanent closure of the inner (lower) half of the Fallopian tubes through a laparoscope by means of a clip (Hulka-Clemens or Filshie clips) or a small plastic ring (Falope ring) or by introducing a rapid-setting plastic into the tubes through a hysteroscope. Men are usually sterilized by vasectomy.

2 the process by which all types of microorganisms (including spores) are destroyed. This is achieved by the use of heat, radiation, chemicals, or filtration. See also AUTOCLAVE.
Top

Back  -    New Search

stern- (sterno-) prefix

denoting the sternum.

Back  -    New Search

sternocleidomastoid muscle (ster-noh-kly-doh-mas-toid) n.

see STERNOMASTOID MUSCLE.

Back  -    New Search

sternohyoid (ster-noh-hy-oid) n.

a muscle in the neck, arising from the sternum and inserted into the hyoid bone. It depresses the hyoid bone.

Back  -    New Search

sternomastoid muscle (sternocleidomastoid muscle) (ster-noh-mas-toid) n.

a long muscle in the neck, extending from the mastoid process to the sternum and clavicle. It serves to rotate the neck and flex the head.

Back  -    New Search

sternomastoid tumour n.

a small painless nonmalignant swelling in the lower half of the sternomastoid muscle, appearing a few days after birth. It is most common after breech births. The tumour may cause a slight tilt of the head, which can be corrected by physiotherapy.

Back  -    New Search

sternotomy (ster-not-mi) n.

surgical division of the sternum, performed to allow access to the heart and its major vessels.

Back  -    New Search

sternum (ster-nm) n. (pl. sterna)

the breastbone: a flat bone extending from the base of the neck to just below the diaphragm and forming the front part of the skeleton of the thorax. The sternum articulates with the collar bones (see CLAVICLE) and the costal cartilages of the first seven pairs of ribs.
—sternal adj.

Back  -    New Search

steroid (steer-oid) n.

one of a group of organic compounds that include the male and female sex hormones (androgens and oestrogens), the hormones of the adrenal cortex (see CORTICOSTEROID), progesterone, bile salts, and sterols. Synthetic steroids have been produced for therapeutic purposes.

Back  -    New Search

sterol (steer-ol) n.

one of a group of steroid alcohols. The most important sterols are cholesterol and ergosterol.

Back  -    New Search

stertor (ster-ter) n.

a snoring type of noisy breathing heard in deeply unconscious patients.

Back  -    New Search

steth- (stetho-) prefix

denoting the chest.

Back  -    New Search

stethoscope (steth--skohp) n.

an instrument used for listening to sounds within the body (see AUSCULTATION). A simple stethoscope usually consists of a diaphragm or an open bell-shaped structure (which is applied to the body) connected by rubber or plastic tubes to shaped ear-pieces for the examiner.

Back  -    New Search

Stevens-Johnson syndrome (stee-vnz jon-sn) n.

an inflammatory condition characterized by fever, large blisters on the skin, and ulceration of the mucous membranes. It may be a severe allergic reaction to certain drugs or it may follow certain infections. [A. M. Stevens (1884–1945) and F. C. Johnson (1894–1934), US paediatricians]

Back  -    New Search

sthenia (sthee-ni) n.

a state of normal or greater than normal strength. Compare ASTHENIA.
—sthenic (sthen-ik) adj.

Back  -    New Search

stibophen (stib-oh-fen) n.

a sodium-containing salt of antimony administered by injection to treat schistosomiasis.

Back  -    New Search

stigma (stig-m) n.(pl. stigmata)

1 a mark that characterizes a particular disease, such as the café au lait spots characteristic of neurofibromatosis.

2 any spot or lesion on the skin.
Top

Back  -    New Search

stilboestrol (stil-bee-strl) n.

a synthetic female sex hormone (see OESTROGEN) administered by mouth or as pessaries to relieve menstrual disorders and symptoms of the menopause, to treat prostate and breast cancer, and to suppress lactation. Trade names: Apstil , Tampovagan .

Back  -    New Search

stilet (stylet, stylus) (sty-lit) n.

1 a slender probe.

2 a wire placed in the lumen of a catheter to give it rigidity while the instrument is passed along a body canal.
Top

Back  -    New Search

stillbirth (stil-berth) n.

birth of a fetus that shows no evidence of life (heartbeat, respiration, or independent movement) at any time later than 24 weeks after conception. A fetus born dead before this time is known as an abortion or miscarriage.

Back  -    New Search

Still's disease (stilz) n.

chronic arthritis developing in children before the age of 16. Some authorities confine the diagnosis of Still's disease to the following: a disease of childhood marked by arthritis (often involving several joints) with a swinging fever and a transitory red rash. The condition may be complicated by enlargement of the spleen and lymph nodes and inflammation of the pericardium and iris. [Sir G. F. Still (1868–1941), British physician]

Back  -    New Search

stimulant (stim-yoo-lnt) n.

an agent that promotes the activity of a body system or function. Amphetamine and caffeine are stimulants of the central nervous system.

Back  -    New Search

stimulator (stim-yoo-lay-ter) n.

any apparatus designed to stimulate nerves and muscles for a variety of purposes. It can be used to stimulate particular areas of the brain or to block pain (as in transcutaneous electrical nerve stimulation; TENS ).

Back  -    New Search

stimulus (stim-yoo-ls) n. (pl. stimuli)

any agent that provokes a response, or particular form of activity, in a cell, tissue, or other structure.

Back  -    New Search

stirrup (sti-rp) n.

(in anatomy) see STAPES.

Back  -    New Search

stitch (stich) n.

1 a sharp localized pain, commonly in the abdomen, associated with strenuous physical activity. It is a form of cramp.

2 see SUTURE.
Top

Back  -    New Search

stock culture (stok) n.

see CULTURE.

Back  -    New Search

Stockholm technique (stok-hohm) n.

a treatment for cervical cancer involving three successive applications of radium.

Back  -    New Search

Stokes-Adams syndrome (stohks-ad-mz) n.

attacks of temporary loss of consciousness that occur when blood flow ceases due to ventricular fibrillation or asystole. This syndrome may complicate heart block. It is treated by means of a battery-operated pacemaker. [W. Stokes (1804–78) and R. Adams (1791–1875), Irish physicians]

Back  -    New Search

stoma (stoh-m) n. (pl. stomata)

1 (in anatomy) the mouth or any mouthlike part.

2 (in surgery) the artificial opening of a tube that has been brought to the abdominal surface (see COLOSTOMY, ILEOSTOMY). s. therapist a nurse specially trained in the care of these openings and the appliances used with them.
Top

—stomal adj.

Back  -    New Search

stomach (stum-k) n.

a distensible saclike organ that forms part of the alimentary canal between the oesophagus and the duodenum. The stomach lies just below the diaphragm, to the right of the spleen. Its function is to continue the process of digestion that begins in the mouth. Gastric juice, secreted by gastric glands in the mucosa, together with the churning action of the muscular layers of the stomach, reduces the food to a semiliquid partly digested mass that passes on to the duodenum.

Back  -    New Search

stomat- (stomato-) prefix

denoting the mouth.

Back  -    New Search

stomatitis (stoh-m-ty-tis) n.

inflammation of the mucous lining of the mouth.

Back  -    New Search

stomatology (stoh-m-tol-ji) n.

the branch of medicine concerned with diseases of the mouth.

Back  -    New Search

-stomy (-ostomy) suffix

denoting a surgical opening into an organ or part.

Back  -    New Search

stone (stohn) n.

see CALCULUS.

Back  -    New Search

stool (stool) n.

faeces discharged from the anus.

Back  -    New Search

stop needle (stop) n.

a surgical needle with a shank that has a protruding collar to stop it when the needle has been pushed a prescribed distance into the tissue.

Back  -    New Search

strabismus (heterotropia) (str-biz-ms) n.

squint: any abnormal alignment of the two eyes. The strabismus is most commonly horizontal (see ESOTROPIA, EXOTROPIA) but it may also be vertical (see HYPERTROPIA, HYPOTROPIA). Double vision is possible, but the image from the deviating eye usually becomes ignored. See also HETEROPHORIA.

Back  -    New Search

strain (strayn)

1 n. excessive stretching or working of a muscle, resulting in pain and swelling. Compare SPRAIN.

2 n. a group of organisms obtained from a particular source or having special properties distinguishing them from other members of the same species.
Top

3 vb. to damage a muscle by overstretching.
Top

Back  -    New Search

strangulated (strang-yoo-layt-id) adj.

describing a part of the body whose blood supply has been interrupted by compression of a blood vessel. s. hernia see HERNIA.

Back  -    New Search

strangulation (strang-yoo-lay-shn) n.

the closure of a passage, such as the main airway to the lungs (resulting in the cessation of breathing), a blood vessel, or the gastrointestinal tract.

Back  -    New Search

strangury (strang-yoor-i) n.

severe pain in the urethra associated with an intense desire to pass urine, resulting from irritation of the base of the bladder. It may also occur in such conditions as cancer of the base of the bladder, cystitis, or prostatitis, when it is accompanied by the painful passage of a few drops of urine.

Back  -    New Search

stratified (strat-i-fyd) adj.

describing tissue consisting of several layers of cells. See EPITHELIUM.

Back  -    New Search

stratum (strah-tm) n.

a layer of tissue or cells, such as any of the layers of the epidermis. s. corneum the outermost layer of the epidermis.

Back  -    New Search

strawberry mark (strawberry naevus) (straw-b-ri) n.

see NAEVUS.

Back  -    New Search

streak (streek) n.

(in anatomy) a line, furrow, or narrow band.

Back  -    New Search

Streptobacillus (strep-toh-b-sil-s) n.

a genus of Gram-negative aerobic nonmotile rodlike bacteria that tend to form filaments. S. moniliformis the cause of rat-bite fever in man.

Back  -    New Search

streptococcal toxic shock syndrome (strep-t-kok-k'l) n.

see TOXIC SHOCK SYNDROME.

Back  -    New Search

Streptococcus (strep-toh-kok-s) n.

a genus of Gram-positive nonmotile spherical bacteria occurring in chains. Most species are saprophytes, but some are pathogenic. haemolytic streptococci species that destroy red blood cells in blood agar and are the cause of many infections, including bacterial endocarditis (-haemolytic strains), and scarlet fever (ß-haemolytic strains). See also LANCEFIELD CLASSIFICATION, STREPTOKINASE.
—streptococcal adj.

Back  -    New Search

streptodornase (strep-toh-dor-nayz) n.

an enzyme produced by some haemolytic bacteria of the genus Streptococcus that is capable of liquefying pus. See also STREPTOKINASE.

Back  -    New Search

streptokinase (strep-toh-ky-nayz) n.

an enzyme produced by some haemolytic bacteria of the genus Streptococcus that is capable of liquefying blood clots (see FIBRINOLYTIC). It is injected to treat blockage of blood vessels and is also used in combination with streptodornase, applied topically or taken by mouth or injection, to liquefy pus and relieve inflammation. Trade names: Kabikinase , Streptase .

Back  -    New Search

streptolysin (strep-tol-i-sin) n.

an exotoxin that is produced by strains of Streptococcus bacteria and destroys red blood cells.

Back  -    New Search

Streptomyces (strep-toh-my-seez) n.

a genus of aerobic mouldlike bacteria. They are important medically as a source of such antibiotics as streptomycin, actinomycin, chloramphenicol, and neomycin.

Back  -    New Search

streptomycin (strep-toh-my-sin) n.

an antibiotic, derived from the bacterium Streptomyces griseus, that is effective against a wide range of bacterial infections; it is administered by mouth or intramuscular injection. In tuberculosis therapy streptomycin is given in conjunction with other drugs because bacteria soon become resistant to it.

Back  -    New Search

stress (stres) n.

any factor that threatens the health of the body or has an adverse effect on its functioning, such as injury, disease, or worry. Constant stress brings about changes in the balance of hormones in the body.

Back  -    New Search

stretch reflex (myotatic reflex) (strech) n.

the reflex contraction of a muscle in response to its being stretched.

Back  -    New Search

stria (stry-) n. (pl. striae)

(in anatomy) a streak, line, or thin band. striae gravidarum stretch marks: the lines that appear on the skin of the abdomen of pregnant women, due to excessive stretching of the elastic fibres. Red or purple during pregnancy, they become white after delivery.

Back  -    New Search

striated muscle (stry-ayt-id) n.

a tissue that comprises the bulk of the body's musculature. It is also known as skeletal muscle , because it is attached to the skeleton and is responsible for the movement of bones, and voluntary muscle , because it is under voluntary control.

Back  -    New Search

stricture (strik-cher) n.

a narrowing of any tubular structure in the body. A stricture may result from inflammation, muscular spasm, growth of a tumour within the affected part, or from pressure on it by neighbouring organs. urethral s. a fibrous narrowing of the urethra, usually resulting from injury or inflammation. The patient has increasing difficulty in passing urine and may develop retention.

Back  -    New Search

stricturoplasty (strik-cher-oh-plasti) n.

an operation in which a stricture (usually in the small intestine) is widened by cutting it.

Back  -    New Search

stridor (stry-dor) n.

the noise heard on breathing in when the trachea or larynx is obstructed. It tends to be louder and harsher than wheeze.

Back  -    New Search

stroke (apoplexy) (strohk) n.

a sudden attack of weakness affecting one side of the body, resulting from an interruption to the flow of blood to the brain. The primary disease is in the heart or blood vessels and the effect on the brain is secondary. The flow of blood may be prevented by thrombosis or embolism (ischaemic s.) or by haemorrhage (haemorrhagic s.). Prolonged reduction of blood pressure may result in similar brain damage. A stroke can vary in severity from a passing weakness or tingling in a limb (see TRANSIENT ISCHAEMIC ATTACK) to a profound paralysis, coma, and death. See also CEREBRAL HAEMORRHAGE.

Back  -    New Search

stroma (stroh-m) n.

the connective-tissue basis of an organ, as opposed to the functional tissue (parenchyma). For example, the stroma of the erythrocytes is the spongy framework of protein strands within a red blood cell in which the blood pigment haemoglobin is packed; the stroma of the cornea is the transparent fibrous tissue making up the main body of the cornea.

Back  -    New Search

strongyloidiasis (strongyloidosis) (stron-ji-loi-dy--sis) n.

an infestation of the small intestine with the parasitic nematode worm Strongyloides stercoralis. Larvae enter the body through the skin and migrate to the lungs, where they cause tissue destruction and bleeding. Adult worms burrow into the intestinal wall and may cause ulceration, diarrhoea, abdominal pain, nausea, anaemia, and weakness. Treatment involves use of the drug thiabendazole.

Back  -    New Search

strontium (stron-tim) n.

a yellow metallic element, absorption of which causes bone damage when its atoms displace calcium in bone. Symbol: Sr. strontium-90 a radioactive isotope used in radiotherapy for the contact therapy of skin and eye tumours.

Back  -    New Search

struma (stroo-m) n. (pl. strumae)

a swelling of the thyroid gland (see GOITRE).

Back  -    New Search

strychnine (strik-neen) n.

a poisonous alkaloid produced in the seeds of the East Indian tree Strychnos nux-vomica. Poisoning causes painful muscular spasms similar to those of tetanus; death is likely to occur from spasm in the respiratory muscles.

Back  -    New Search

S-T segment n.

the segment on an electrocardiogram that represents the interval preceding the last phase of the cardiac cycle, when the heart recovers from contraction.

Back  -    New Search

stupe (stewp) n.

any piece of material, such as a wad of cottonwool, soaked in hot water (with or without medication) and used to apply a poultice.

Back  -    New Search

stupor (stew-per) n.

a condition of near unconsciousness, with apparent mental inactivity and reduced ability to respond to stimulation.

Back  -    New Search

Sturge-Weber syndrome (sterj-web-er) n.

angioma of the blood vessels overlying the brain associated with a port-wine stain on the face (see NAEVUS). [W. A. Sturge (1850–1919) and F. P. Weber (1863–1962), British physicians]

Back  -    New Search

stuttering (stut-er-ing) n.

see STAMMERING.

Back  -    New Search

St Vitus' dance (snt vy-ts dahns) n.

an archaic name for Sydenham's chorea.

Back  -    New Search

stye (sty) n.

acute inflammation of a gland at the base of an eyelash, caused by bacterial infection. The gland becomes hard and tender and a pus-filled cyst develops at its centre. Medical name: hordeolum .

Back  -    New Search

stylet (sty-lit) n.

see STILET.

Back  -    New Search

stylo- prefix

denoting the styloid process of the temporal bone.

Back  -    New Search

styloid process (sty-loid) n.

1 a long slender downward-pointing spine projecting from the lower surface of the temporal bone of the skull. It provides attachment for muscles and ligaments of the tongue and hyoid bone.

2 any of various other spiny projections.
Top

Back  -    New Search

stylus (sty-ls) n.

1 a pencil-shaped instrument, commonly used for applying external medication.

2 see STILET.
Top

Back  -    New Search

styptic (stip-tik) n.

see HAEMOSTATIC.

Back  -    New Search

sub- prefix

denoting 1 below; underlying.

2 partial or slight.
Top

Back  -    New Search

subacute (sub--kewt) adj.

describing a disease that progresses more rapidly than a chronic condition but does not become acute.

Back  -    New Search

subacute bacterial endocarditis n.

a form of endocarditis characterized by a slow onset and protracted course. It is usually caused by species of Streptococcus or Staphylococcus.

Back  -    New Search

subacute combined degeneration of the cord n.

the neurological disorder complicating a deficiency of vitamin B_12 and pernicious anaemia. There is selective damage to the motor and sensory nerve fibres in the spinal cord, resulting in spasticity of the limbs and a sensory ataxia.

Back  -    New Search

subacute sclerosing panencephalitis (SSPE) (skleer-ohz-ing pan-en-sef--ly-tis) n.

a rare and late complication of measles characterized by a slow progressive neurological deterioration that is usually fatal. It can occur four to ten years after the initial infection.

Back  -    New Search

subarachnoid haemorrhage (sub--rak-noid) n.

bleeding into the subarachnoid space, which causes severe headache with stiffness of the neck. The usual source of such a haemorrhage is a cerebral aneurysm that has burst.

Back  -    New Search

subarachnoid space n.

the space between the arachnoid and pia meninges of the brain and spinal cord, containing circulating cerebrospinal fluid and large blood vessels.

Back  -    New Search

subclavian artery (sub-klay-vi-n) n.

either of two arteries supplying blood to the neck and arms. The right subclavian artery branches from the innominate artery; the left subclavian arises directly from the aortic arch.

Back  -    New Search

subclavian steal syndrome (steel) n.

diversion of blood from the vertebral artery to the subclavian artery when the latter is blocked proximally. It causes attacks of diminished consciousness (syncope).

Back  -    New Search

subclinical (sub-klin-ikl) adj.

describing a disease that is suspected but is not sufficiently developed to produce definite signs and symptoms in the patient.

Back  -    New Search

subconscious (sub-kon-shs) adj.

(in psychoanalysis) denoting the part of the mind that includes memories, motives, and intentions that are momentarily not present in consciousness but can more or less readily be recalled to awareness. Compare UNCONSCIOUS.

Back  -    New Search

subcutaneous (sub-kew-tay-nis) adj.

beneath the skin. See also INJECTION. s. tissue loose connective tissue, often fatty, situated under the dermis.

Back  -    New Search

subdural (sub-dewr-l) adj.

below the dura mater; relating to the space between the dura mater and arachnoid. s. haematoma see HAEMATOMA.

Back  -    New Search

subglottis (sub-glot-iss) n.

that part of the larynx that lies below the vocal folds.

Back  -    New Search

subinvolution (sub-in-v-loo-shn) n.

failure of the uterus to revert to its normal size during the six weeks following childbirth.

Back  -    New Search

subjective (sub-jek-tiv) adj.

apparent to the affected individual but not to others: applied particularly to symptoms.

Back  -    New Search

sublimation (sub-li-may-shn) n.

the replacement of socially undesirable means of gratifying motives or desires by means that are socially acceptable. See also DEFENCE MECHANISM, REPRESSION.

Back  -    New Search

subliminal (sub-lim-inl) adj.

subconscious: beneath the threshold of conscious perception.

Back  -    New Search

sublingual gland (sub-ling-wl) n.

one of a pair of salivary glands situated in the lower part of the mouth, one on either side of the tongue.

Back  -    New Search

subluxation (sub-luks-ay-shn) n.

partial dislocation of a joint, so that the bone ends are misaligned but still in contact.

Back  -    New Search

submandibular gland (submaxillary gland) (sub-man-dib-yoo-ler) n.

one of a pair of salivary glands situated below the parotid glands.

Back  -    New Search

submaxillary gland (sub-maks-il-er-i) n.

see SUBMANDIBULAR GLAND.

Back  -    New Search

submucosa (sub-mew-koh-sa) n.

the layer of loose connective (areolar) tissue underlying a mucous membrane.
—submucosal adj.

Back  -    New Search

submucous (sub-mew-ks) adj.

beneath a mucous membrane. s. resection see RESECTION.

Back  -    New Search

subphrenic abscess (sub-fren-ik) n.

a collection of pus in the space below the diaphragm, usually on the right side, between the liver and diaphragm. Causes include postoperative infection and perforation of an organ.

Back  -    New Search

substitution (sub-sti-tew-shn) n.

(in psychoanalysis) the replacement of one idea by another: a form of defence mechanism.

Back  -    New Search

substitution therapy n.

treatment by providing a less harmful alternative to a drug or remedy that a patient has been receiving.

Back  -    New Search

substrate (sub-strayt) n.

the specific substance or substances on which a given enzyme acts.

Back  -    New Search

subsultus (sub-sul-tus) n.

abnormal twitching or tremor of muscles, such as may occur in feverish conditions.

Back  -    New Search

subtertian fever (sub-ter-shn) n.

a form of malaria resulting from repeated infection by Plasmodium falciparum and characterized by continuous fever.

Back  -    New Search

succus (suk-s) n.

any juice or secretion of animal or plant origin. s. entericus (intestinal juice) the clear alkaline fluid secreted by the glands of the small intestine. It contains mucus and digestive enzymes.

Back  -    New Search

succussion (suk-ush-n) n.

a splashing noise heard when a patient who has a large quantity of fluid in a body cavity, such as the pleural cavity, moves suddenly or is deliberately shaken.

Back  -    New Search

sucralfate (sewk-rl-fayt) n.

an aluminium-containing drug that forms a protective coating over the stomach or duodenal lining. Administered by mouth, sucralfate is used in the treatment of peptic ulcer. Trade name: Antepsin .

Back  -    New Search

sucrose (sewk-rohz) n.

a carbohydrate consisting of glucose and fructose. It is the principal constituent of cane sugar and sugar beet. The increasing consumption of sucrose in the last 50 years has coincided with an increase in the incidence of dental caries, diabetes, coronary heart disease, and obesity.

Back  -    New Search

suction (suk-shn) n.

the use of reduced pressure to remove unwanted fluids or other material through a tube for disposal. During surgery, suction tubes are used to remove blood from the area of operation and to decompress the stomach (nasogastric s.) and the pleural space of air and blood (chest s.).

Back  -    New Search

sudden infant death syndrome (SIDS) n.

see COT DEATH.

Back  -    New Search

Sudek's atrophy (soo-deks) n.

pain, swelling, stiffness, and skin changes, usually in a hand or foot, caused by overactivity of the sympathetic nervous system following trauma (often a Colles' fracture) or surgery or occasionally arising spontaneously. [P. H. M. Sudek (1866–1938), German surgeon]

Back  -    New Search

sudor (s'yoo-dor) n.

see SWEAT.

Back  -    New Search

sudorific (s'yoo-der-if-ik) n.

see DIAPHORETIC.

Back  -    New Search

suffocation (suf--kay-shn) n.

cessation of breathing as a result of drowning, smothering, etc., leading to unconsciousness or death (see ASPHYXIA).

Back  -    New Search

suffusion (s-few-zhn) n.

the spreading of a flush across the skin surface, caused by changes in the local blood supply.

Back  -    New Search

sugar (shuug-er) n.

any carbohydrate that dissolves in water, is usually crystalline, and has a sweet taste. Sugars are classified chemically as monosaccharides or disaccharides. Table sugar is virtually 100% pure sucrose. See also FRUCTOSE, GLUCOSE, LACTOSE.

Back  -    New Search

suggestibility (s-jes-ti-bil-iti) n.

the state of readily accepting suggestions from others.
—suggestible adj.

Back  -    New Search

suggestion (s-jes-chn) n.

(in psychology) the process of changing people's beliefs, attitudes, or emotions by telling them that they will change. It is sometimes used as a synonym for hypnosis. See also AUTOSUGGESTION.

Back  -    New Search

suicide (soo-i-syd) n.

self-destruction as a deliberate act. attempted s. an attempt at self-destruction in which death is averted although the person concerned intended to kill himself (or herself). Compare PARASUICIDE.

Back  -    New Search

sulcus (sul-ks) n. (pl. sulci)

1 one of the many clefts or infoldings of the surface of the brain.

2 any of the infoldings of soft tissue in the mouth.
Top

Back  -    New Search

sulfametopyrazine (sul-f-met-oh-py-r-zeen) n.

see SULPHONAMIDE.

Back  -    New Search

sulphacetamide (sul-f-set--myd) n.

a drug of the sulphonamide group that is used in eye drops to treat such infections as conjunctivitis. Trade names: Albucid , Ocusol .

Back  -    New Search

sulphadiazine (sul-f-dy--zeen) n.

see SULPHONAMIDE.

Back  -    New Search

sulphadimidine (sul-f-dy-mi-deen) n.

see SULPHONAMIDE.

Back  -    New Search

sulpha drug (sul-f) n.

see SULPHONAMIDE.

Back  -    New Search

sulphamethoxazole (sul-f-meth-oks--zohl) n.

a drug of the sulphonamide group. It is taken by mouth and is effective in the treatment of infections of the respiratory, urinary, and gastrointestinal tracts and the skin. The drug is combined with trimethoprim in co-trimoxazole.

Back  -    New Search

sulphasalazine (sul-f-sal--zeen) n.

a drug of the sulphonamide group, used in the treatment of ulcerative colitis. It is given by mouth or in the form of suppositories. Trade name: Salazopyrin .

Back  -    New Search

sulphinpyrazone (sul-fin-py-r-zohn) n.

a uricosuric drug given by mouth for the treatment of chronic gout. It should not be taken by patients with impaired kidney function. Trade name: Anturan .

Back  -    New Search

sulphonamide (sulpha drug) (sul-fon--myd) n.

one of a group of drugs, derived from sulphanilamide (a red dye), that prevent the growth of bacteria. Sulphonamides are usually given by mouth and are effective against a variety of infections. Many sulphonamides are rapidly excreted and very soluble in the urine and are therefore used to treat infections of the urinary tract, especially in combination with other drugs. Because of their toxic side-effects, the clinical use of sulphonamides has declined; those still used include sulphadimidine , sulphadiazine , and sulfametopyrazine . See also SULPHACETAMIDE, SULPHAMETHOXAZOLE, SULPHASALAZINE.

Back  -    New Search

sulphone (sul-fohn) n.

one of a group of drugs closely related to the sulphonamides. Sulphones possess powerful activity against the bacteria that cause leprosy and tuberculosis. The best known sulphone is dapsone.

Back  -    New Search

sulphonylurea (sul-f-nil-yoor-i) n.

one of a group of oral hypoglycaemic drugs, derived from a sulphonamide, that are used in the treatment of noninsulin-dependent (Type II) diabetes mellitus. They include chlorpropamide, glibenclamide, tolazamide, and tolbutamide.

Back  -    New Search

sulphur (sul-fer) n.

a nonmetallic element that is active against fungi and parasites. It is a constituent of ointments and other preparations used in the treatment of skin disorders and infections. Symbol: S.

Back  -    New Search

sulphuric acid (sul-fewr-ik) n.

a powerful corrosive acid, widely used in industry. Swallowing the acid causes severe burning of the mouth and throat. The patient should drink large quantities of milk or water or white of egg; gastric lavage should not be delayed. Formula:
H^2SO^4
.

Back  -    New Search

sumatriptan (soo-m-trip-tan) n.

a drug that is effective in the treatment of acute migraine by rapidly reversing the dilatation of blood vessels in the head that causes the migraine headache. It is administered by mouth or by subcutaneous injection. Trade name: Imigran .

Back  -    New Search

sunburn (sun-bern) n.

damage to the skin by excessive exposure to the sun's rays. Sunburn may vary from reddening of the skin to the development of large painful fluid-filled blisters (see BURN).

Back  -    New Search

sunstroke (sun-strohk) n.

see HEATSTROKE.

Back  -    New Search

super- prefix

denoting 1 above; overlying.

2 extreme or excessive.
Top

Back  -    New Search

superciliary (soo-per-sil-i-er-i) adj.

of or relating to the eyebrows (supercilia ).

Back  -    New Search

superego (soo-per-ee-goh) n.

(in psychoanalysis) the part of the mind that functions as a moral conscience or judge. The superego is the result of the incorporation of parental injunctions into the child's mind.

Back  -    New Search

superfecundation (soo-per-fee-kn-day-shn) n.

the fertilization of two or more ova of the same age by spermatozoa from different males. See SUPERFETATION.

Back  -    New Search

superfetation (soo-per-fee-tay-shn) n.

the fertilization of a second ovum some time after the start of pregnancy, resulting in two fetuses of different maturity in the same uterus.

Back  -    New Search

superficial (soo-per-fish-l) adj.

(in anatomy) situated at or close to a surface. Superficial blood vessels are those close to the surface of the skin.

Back  -    New Search

superinfection (soo-per-in-fek-shn) n.

an infection arising during the course of another infection and caused by a different microorganism, which is usually resistant to the drugs used to treat the primary infection. See also MRSA.

Back  -    New Search

superior (soo-peer-i-er) adj.

(in anatomy) situated uppermost in the body in relation to another structure or surface.

Back  -    New Search

superovulation (soo-per-ov-yoo-lay-shn) n.

1 controlled hyperstimulation of the ovary to produce more follicles with oocytes. Usually induced by drugs, it is performed in in vitro fertilization and other procedures of assisted conception in order to improve the pregnancy rates.

2 uncontrolled hyperstimulation of the ovary (ovarian hyperstimulation syndrome ). It may be associated with abdominal pain, ascites, oliguria, or renal failure.
Top

Back  -    New Search

supervisor (soo-per-vy-zer) n.

an appropriately registered nurse who is accountable for a student's standard of care in a clinical area. The supervisor oversees the student's practice and learning experience during a clinical episode.

Back  -    New Search

supination (soo-pi-nay-shn) n.

the act of turning the hand so that the palm is uppermost. Compare PRONATION.

Back  -    New Search

supinator (soo-pi-nay-ter) n.

a muscle of the forearm that extends from the elbow to the shaft of the radius. It supinates the forearm and hand.

Back  -    New Search

supine (soo-pyn) adj.

1 lying on the back or with the face upwards.

2 (of the forearm) in the position in which the palm of the hand faces upwards. Compare PRONE.
Top

Back  -    New Search

supportive (s-port-iv) adj.

(of treatment) aimed at reinforcing the patient's own defence mechanisms in overcoming a disease or disorder.

Back  -    New Search

support worker (s-port) n.

(in the health service) a nursing auxiliary or assistant, physiotherapy helper, occupational therapy helper, speech therapy assistant, foot-care assistant, or ward clerk. Support workers in nursing care work under the supervision of registered practitioners (see HEALTH-CARE ASSISTANT).

Back  -    New Search

suppository (s-poz-it-er-i) n.

a medicinal preparation in solid form suitable for insertion into a body cavity. rectal s. a suppository that is inserted into the rectum. It may contain drugs that act locally in the rectum or anus, drugs that are absorbed and act at other sites, or a simple lubricant. vaginal s. see PESSARY.

Back  -    New Search

suppression (s-presh-n) n.

1 the cessation or complete inhibition of any physiological activity.

2 treatment that removes the outward signs of an illness or prevents its progress.
Top

3 (in psychology) a defence mechanism by which a person consciously and deliberately ignores an idea that is unpleasant to him.
Top

Back  -    New Search

suppuration (sup-yoor-ay-shn) n.

the formation of pus.

Back  -    New Search

supra- prefix

denoting above; over.

Back  -    New Search

supraglottis (soo-pr-glot-iss) n.

that part of the larynx that lies above the vocal folds and includes the epiglottis.

Back  -    New Search

supraorbital (soo-pr-or-bit'l) adj.

of or relating to the area above the eye orbit. s. reflex the closing of the eyelids when the supraorbital nerve is struck, due to contraction of the muscle surrounding the orbit.

Back  -    New Search

suprapubic (soo-pr-pew-bik) adj.

above the pubic bone. s. cystotomy see CYSTOTOMY.

Back  -    New Search

suprarenal glands (soo-pr-ree-nl) pl. n.

see ADRENAL GLANDS.

Back  -    New Search

suramin (s'yoor--min) n.

a nonmetallic drug used in the treatment of trypanosomiasis. It is usually given by slow intravenous injection.

Back  -    New Search

surfactant (ser-fak-tnt) n.

a wetting agent. pulmonary s. a complex mixture of compounds, secreted by pneumocytes, that prevents the alveoli of the lungs from collapsing by reducing surface tension.

Back  -    New Search

surgeon (serj-n) n.

a qualified medical practitioner who specializes in surgery.

Back  -    New Search

surgery (serj-er-i) n.

the branch of medicine that treats injuries, deformities, or disease by operation or manipulation. See also CRYOSURGERY, MICROSURGERY.
—surgical adj.

Back  -    New Search

surgical neck (serj-ikl) n.

the constriction of the shaft of the humerus, below the head. It is frequently the point at which fracture of the humerus occurs.

Back  -    New Search

surgical spirit n.

methylated spirit, usually with small amounts of castor oil and oil of wintergreen: used to sterilize the skin before surgery, injections, etc.

Back  -    New Search

surrogate (su-r-gt) n.

(in psychology) a person or object in someone's life that functions as a substitute for another person. s. mother a woman who becomes pregnant (by artificial insemination or embryo insertion) following an arrangement made with another party (usually a couple unable themselves to have children) in which she agrees to hand over the child she carries to that party when it is born.

Back  -    New Search

susceptibility (s-sep-ti-bil-iti) n.

lack of resistance to disease. It is partly influenced by vaccination or other methods of increasing resistance to specific diseases.

Back  -    New Search

suspensory bandage (su-spen-ser-i) n.

a bandage arranged to support a hanging part of the body, such as the scrotum.

Back  -    New Search

suspensory ligament n.

a ligament that serves to support or suspend an organ, such as the lens of the eye, in position.

Back  -    New Search

sustentaculum (sus-ten-tak-yoo-lm) n.

any anatomical structure that supports another structure.
—sustentacular adj.

Back  -    New Search

suture (soo-cher)

1 n. (in anatomy) a type of immovable joint, found particularly in the skull, characterized by a minimal amount of connective tissue between the two bones.

2 n. (in surgery) the closure of a wound or incision with material such as silk or catgut, to facilitate the healing process. See also DELAYED SUTURE.
Top

3 n. the material – silk, catgut, nylon, a polymer, or wire – used to sew up a wound.
Top

4 vb. to close a wound by suture.

Top

Back  -    New Search

suxamethonium (suks--mth-oh-nim) n.

a drug that relaxes voluntary muscle (see MUSCLE RELAXANT). It is administered by intravenous injection and is used mainly to produce muscle relaxation during surgery. Trade names: Anectine , Scoline .

Back  -    New Search

swab (swob) n.

a pad of absorbent material (such as cotton), sometimes attached to a stick or wire, that is used for cleaning out or applying medication to wounds, operation sites, or body cavities.

Back  -    New Search

swallowing (deglutition) (swol-oh-ing) n.

the process by which food is transferred from the mouth to the oesophagus. Voluntary raising of the tongue forces food backwards towards the pharynx. This stimulates reflex actions in which the larynx and the nasal passages are closed so that food does not enter the trachea.

Back  -    New Search

Swan-Ganz catheter (swon-ganz) n.

a catheter with an inflatable balloon at its tip, which can be inserted into the pulmonary artery via the right chambers of the heart. Inflation of the balloon enables measurement of pressure in the left atrium and hence pulmonary artery pressure. [H. J. C. Swan (1922– ), US cardiologist; W. Ganz (20th century), US engineer]

Back  -    New Search

sweat (swet) n.

the watery fluid secreted by the sweat glands. Its principal constituents in solution are sodium chloride and urea. The secretion of sweat is a means of excreting nitrogenous waste; it also has a cooling effect as the sweat evaporates from the surface of the skin. Anatomical name: sudor. s. gland a simple coiled tubular exocrine gland that lies in the dermis of the skin. Sweat glands occur over most of the surface of the body; they are particularly abundant in the armpits, on the soles of the feet and palms of the hands, and on the forehead.

Back  -    New Search

sycosis (sy-koh-sis) n.

inflammation of the hair follicles caused by infection with Staphylococcus aureus. It commonly affects the beard area (s. barbae ) of men in their thirties or forties.

Back  -    New Search

Sydenham's chorea (sid-n-mz) n.

see CHOREA. [T. Sydenham (1624–89), English physician]

Back  -    New Search

symbiosis (sim-by-oh-sis) n.

an intimate and obligatory association between two different species of organism (symbionts ) in which there is mutual aid and benefit. Compare COMMENSAL, PARASITE.

Back  -    New Search

symblepharon (sim-blef-er-on) n.

a condition in which the eyelid adheres to the eyeball. It is usually the result of chemical (especially alkali) burns to the conjunctiva.

Back  -    New Search

symbolism (sim-bl-izm) n.

(in psychology) the process of representing an object or an idea by something else. Psychoanalytic theorists hold that conscious ideas frequently act as symbols for unconscious thoughts and that this is particularly evident in dreaming, in free association, and in the formation of psychological symptoms.
—symbolic (sim-bol-ik) adj.

Back  -    New Search

Syme's amputation (symz) n.

amputation of the foot just above the ankle joint. [J. Syme (1799–1870), British surgeon]

Back  -    New Search

symmetry (sim-it-ri) n.

(in anatomy) the state of opposite parts of an organ or parts at opposite sides of the body corresponding to each other.

Back  -    New Search

sympathectomy (sim-p-thek-tmi) n.

the surgical division of sympathetic nerve fibres. It is done to minimize the effects of normal or excessive sympathetic activity.

Back  -    New Search

sympathetic nervous system (sim-p-thet-ik) n.

one of the two divisions of the autonomic nervous system, having fibres that leave the central nervous system in the thoracic and lumbar regions and are distributed to the blood vessels, sweat glands, salivary glands, heart, lungs, intestines, and other abdominal organs. The nerve endings release noradrenaline as a neurotransmitter.

Back  -    New Search

sympathin (sim-p-thin) n.

the name given by early physiologists to the substances released from sympathetic nerve endings, now known to be a mixture of adrenaline and noradrenaline.

Back  -    New Search

sympatholytic (sim-p-thoh-lit-ik) n.

a drug that opposes the effects of the sympathetic nervous system. Sympatholytic drugs include guanethidine, phentolamine, and propranolol.

Back  -    New Search

sympathomimetic (sim-p-thoh-mi-met-ik) n.

a drug that has the effect of stimulating the sympathetic nervous system. The actions of sympathomimetic drugs are adrenergic (resembling those of noradrenaline). Sympathomimetic drugs include phenylephrine, salbutamol, ephedrine, and isoprenaline.

Back  -    New Search

sympathy (sim-p-thi) n.

(in physiology) a reciprocal influence exercised by different parts of the body on one another.

Back  -    New Search

symphysiotomy (sim-fizi-ot-mi) n.

the operation of cutting through the front of the pelvis at the pubic symphysis in order to enlarge the diameter of the pelvis and aid delivery of a fetus whose head is too large to pass through the pelvic opening. This procedure is now rarely employed.

Back  -    New Search

symphysis (sim-fi-sis) n.

1 a joint in which the bones are separated by fibrocartilage, which minimizes movement and makes the bony structure rigid. Examples are the public symphysis (see PUBIS) and the joints of the backbone, which are separated by intervertebral discs.

2 the line that marks the fusion of two bones that were separate at an early stage of development.
Top

Back  -    New Search

symptom (simp-tm) n.

an indication of a disease or disorder noticed by the patient himself. Compare SIGN.

Back  -    New Search

symptomatology (semeiology) (simp-tm--tol-ji) n.

1 the branch of medicine concerned with the study of symptoms of disease.

2 the symptoms of a disease, collectively.
Top

Back  -    New Search

syn- (sym-) prefix

denoting union or fusion.

Back  -    New Search

synaesthesia (sin-is-theez-i) n.

a condition in which a secondary subjective sensation (often colour) is experienced at the same time as the sensory response normally evoked by the stimulus. For example, the sound of the word ‘cat’ might evoke the colour purple.

Back  -    New Search

synalgia (sin-al-ji) n.

see REFERRED PAIN.

Back  -    New Search

synapse (sy-naps) n.

the minute gap across which nerve impulses pass from one neurone to the next, at the end of a nerve fibre. Reaching a synapse, an impulse causes the release of a neurotransmitter, which diffuses across the gap and triggers an electrical impulse in the next neurone. See also NEUROMUSCULAR JUNCTION.

Back  -    New Search

synarthrosis (sin-arth-roh-sis) n.

an immovable joint in which the bones are united by fibrous tissue. Examples are the cranial sutures. See also GOMPHOSIS, SCHINDYLESIS.

Back  -    New Search

synchondrosis (sin-kon-droh-sis) n.

a slightly movable joint (see AMPHIARTHROSIS) in which the surfaces of the bones are separated by hyaline cartilage, as occurs between the ribs and sternum.

Back  -    New Search

synchysis (sink-i-sis) n.

softening of the vitreous humour of the eye. s. scintillans tiny refractile crystals of cholesterol suspended in the vitreous humour. They usually cause no symptoms.

Back  -    New Search

syncope (fainting) (sink--pi) n.

loss of consciousness induced by a temporarily insufficient flow of blood to the brain. It commonly occurs in otherwise healthy people and may be caused by an emotional shock, by standing for prolonged periods, or by injury and profuse bleeding.

Back  -    New Search

syncytium (sin-sit-im) n. (pl. syncytia)

a mass of protoplasm containing several nuclei. Muscle fibres are syncytia.
—syncytial adj.

Back  -    New Search

syndactyly (dactylion) (sin-dak-tili) n.

congenital webbing of the fingers, which are joined along part or all of their length. Adjacent fingers may be joined only by skin, or the bones of the fingers may be joined.

Back  -    New Search

syndesm- (syndesmo-) prefix

denoting connective tissue, particularly ligaments.

Back  -    New Search

syndesmology (sin-des-mol-ji) n.

the branch of anatomy dealing with joints and their components.

Back  -    New Search

syndesmosis (sin-des-moh-sis) n.

an immovable joint in which the bones are separated by connective tissue. An example is the articulation between the bases of the tibia and fibula.

Back  -    New Search

syndrome (sin-drohm) n.

a combination of signs and/or symptoms that forms a distinct clinical picture indicative of a particular disorder.

Back  -    New Search

synechia (sin-ek-i) n.

an adhesion between the iris and another part of the eye. anterior s. synechia between the iris and the cornea. posterior s. synechia between the iris and the lens.

Back  -    New Search

syneresis (sin-eer-i-sis) n.

contraction of a blood clot to produce a firm mass that seals the damaged blood vessels.

Back  -    New Search

synergist (sin-er-jist) n.

1 a drug that interacts with another to produce increased activity, which is greater than the sum of the effects of the two drugs given separately.

2 a muscle that acts with a prime mover (agonist) in making a particular movement.
Top

—synergism, synergy n. —synergistic (sin-er-jist-ik) adj.

Back  -    New Search

synergistic gangrene n.

gangrene of tissues produced by different bacteria acting together, usually a mixture of aerobic and anaerobic organisms. Synergistic gangrene has a pronounced tendency to spread along fascial planes, causing necrotizing fasciitis.

Back  -    New Search

syngeneic (sin-jn-ay-ik) adj.

describing grafted tissue that is genetically identical to the recipient's tissue, as when the donor and recipient are identical twins.

Back  -    New Search

synoptophore (sin-op-toh-for) n.

see AMBLYOSCOPE.

Back  -    New Search

synostosis (sin-os-toh-sis) n.

the joining by ossification of two adjacent bones. It occurs, for example, at the cranial sutures.

Back  -    New Search

synovectomy (sy-noh-vek-tmi) n.

surgical removal of the synovium of a joint. This is performed in cases of chronic synovitis, when other measures have been ineffective.

Back  -    New Search

synovia (synovial fluid) (sy-noh-vi-) n.

the thick colourless lubricating fluid that surrounds a joint or a bursa and fills a tendon sheath. It is secreted by the synovial membrane.

Back  -    New Search

synovial joint (sy-noh-vi-l) n.

see DIARTHROSIS.

Back  -    New Search

synovial membrane (synovium) n.

the membrane that forms the sac enclosing a freely movable joint (see DIARTHROSIS). It secretes the lubricating synovial fluid.

Back  -    New Search

synovioma (sy-noh-vi-oh-m) n.

a benign or malignant tumour of the synovial membrane.

Back  -    New Search

synovitis (sy-noh-vy-tis) n.

inflammation of the synovial membrane, resulting in pain and swelling (arthritis). It is caused by injury, infection, or rheumatic disease.

Back  -    New Search

synovium (sy-noh-vi-m) n.

see SYNOVIAL MEMBRANE.

Back  -    New Search

synthesis (sin-thi-sis) n.

the formation of complex substances from simple constituents.
—synthesize vb. —synthetic (sin-thet-ik) adj.

Back  -    New Search

syphilide (syphilid) (sif-i-lyd) n.

the skin rash that appears in the second stage of syphilis. Syphilides occur in crops that may last from a few days to several months. They denote a highly infectious stage of the disease.

Back  -    New Search

syphilis (sif-i-lis) n.

a chronic sexually transmitted disease caused by the bacterium Treponema pallidum. Bacteria usually enter the body during sexual intercourse; they may also pass from an infected pregnant woman across the placenta to the developing fetus, resulting in the disease being present at birth (congenital s. ). The primary symptom is a hard ulcer (chancre) at the site of infection. Secondary stage symptoms include fever, malaise, general enlargement of lymph nodes, and a faint red rash on the chest. After months, or even years, the disease enters its tertiary stage with widespread formation of tumour-like masses (gummas). Tertiary syphilis may cause serious damage to the heart and blood vessels (cardiovascular s. ) or to the brain and spinal cord (neurosyphilis ), resulting in tabes dorsalis, blindness, and general paralysis of the insane. See also BEJEL.
—syphilitic (sif-i-lit-ik) adj.

Back  -    New Search

syring- (syringo-) prefix

denoting a tube or long cavity, especially the central canal of the spinal cord.

Back  -    New Search

syringe (si-rinj) n.

an instrument consisting of a piston in a tight-fitting tube that is attached to a hollow needle or thin tube. A syringe is used to give injections, remove material from a part of the body, or to wash out a cavity.

Back  -    New Search

syringobulbia (si-ring-oh-bulb-i) n.

see SYRINGOMYELIA.

Back  -    New Search

syringoma (si-ring-oh-m) n.

multiple benign tumours of the sweat glands, which show as small hard swellings usually on the face, neck, or chest.

Back  -    New Search

syringomyelia (si-ring-oh-my-ee-li) n.

a disease of the spinal cord in which longitudinal cavities form within the cord in the cervical (neck) region. Characteristically there is weakness and wasting of the muscles in the hands with a loss of awareness of pain and temperature. An extension of the cavitation into the lower brainstem is called syringobulbia . Cerebellar ataxia, a partial loss of pain sensation in the face, and weakness of the tongue and palate may occur.

Back  -    New Search

syringomyelocele (si-ring-oh-my-l-oh-seel) n.

protrusion of the spinal cord through a defect in the spine together with a fluid-filled sac continuous with the central canal of the cord.

Back  -    New Search

system (sis-tm) n.

(in anatomy) a group of organs and tissues associated with a particular physiological function, such as the nervous system or respiratory system.

Back  -    New Search

systemic (sis-tem-ik) adj.

relating to or affecting the body as a whole, rather than individual parts and organs. s. circulation see CIRCULATION. s. sclerosis a rare multisystem connective-tissue disease in which scleroderma may be associated with pulmonary fibrosis, renal failure, and gastrointestinal and myocardial disease. Genetic and autoimmune factors may be implicated.

Back  -    New Search

systole (sis-t-li) n.

the period of the cardiac cycle during which the heart contracts.
—systolic (sis-tol-ik) adj.

Back  -    New Search

systolic pressure n.

see BLOOD PRESSURE.

Back  -    New Search

T

tabes dorsalis (locomotor ataxia) (tay-beez dor-sah-lis) n.

a form of neurosyphilis occurring 5–20 years after the original sexually transmitted infection. The infecting organisms progressively destroy the sensory nerves. Severe stabbing pains in the legs and trunk, an unsteady gait, and loss of bladder control are common. See also SYPHILIS, GENERAL PARALYSIS OF THE INSANE.

Back  -    New Search

tablet (tab-lit) n.

(in pharmacy) a small disc containing one or more drugs, made by compressing a powdered form of the drug(s). It is usually taken by mouth.

Back  -    New Search

tabo-paresis (tay-boh-p-ree-sis) n.

a late effect of syphilitic infection of the nervous system in which the patient shows features of tabes dorsalis and general paralysis of the insane.

Back  -    New Search

TAB vaccine n.

a combined vaccine used to produce immunity against the diseases typhoid, paratyphoid A, and paratyphoid B.

Back  -    New Search

tachy- prefix

denoting fast; rapid.

Back  -    New Search

tachycardia (tak-i-kar-di) n.

an increase in the heart rate above normal. sinus t. tachycardia that may occur normally with exercise or excitement. It may also be due to illness, such as fever.

Back  -    New Search

tachypnoea (tak-ip-nee-) n.

rapid breathing.

Back  -    New Search

tacrolimus (FK506) (tak-r-ly-ms) n.

a powerful immunosuppressive drug used mainly to prevent rejection of transplanted organs. It has also been used to treat allergic skin conditions and psoriasis. Side-effects include damage to the kidneys, and there is an increased risk of developing certain cancers. Trade name: Prograf .

Back  -    New Search

tactile (tak-tyl) adj.

relating to or affecting the sense of touch.

Back  -    New Search

taenia (tee-ni) n. (pl. taeniae)

a flat ribbon-like anatomical structure. taeniae coli the longitudinal ribbon-like muscles of the colon.

Back  -    New Search

Taenia n.

a genus of large tapeworms, some of which are parasites of the human intestine. T. saginata the beef tapeworm: the most common tapeworm parasite of man. See TAENIASIS. T. solium the pork tapeworm. Its larval stage may develop in man, in whom it may cause cysticercosis.

Back  -    New Search

taeniacide (taenicide) (tee-ni-syd) n.

an agent that kills tapeworms.

Back  -    New Search

taeniafuge (tee-ni-fewj) n.

an agent, such as niclosamide, that eliminates tapeworms from the body of their host.

Back  -    New Search

taeniasis (tee-ny--sis) n.

an infestation with tapeworms of the genus Taenia, resulting from ingestion of raw or undercooked meat containing the larval stage of the parasite. Symptoms include increased appetite, hunger pains, weakness, and weight loss. See also CYSTICERCOSIS.

Back  -    New Search

Tagamet (tag-a-met) n.

see CIMETIDINE.

Back  -    New Search

Takayasu's disease (pulseless disease) (tak--yas-ooz) n.

progressive occlusion of the arteries arising from the arch of the aorta (including those to the arms and neck), resulting in the absence of pulses in the arms and neck. Symptoms include attacks of unconsciousness (syncope), paralysis of facial muscles, and transient blindness, due to an inadequate supply of blood to the head. [M. Takayasu (1860–1938), Japanese ophthalmologist]

Back  -    New Search

tal- (talo-) prefix

denoting the ankle bone (talus).

Back  -    New Search

talampicillin (tal-am-pi-sil-in) n.

a penicillin-type antibiotic, chemically related to ampicillin, that is effective against Gram-positive and many Gram-negative organisms (see GRAM'S STAIN). It is administered by mouth. Trade name: Talpen .

Back  -    New Search

talc (tal'k) n.

a soft white powder consisting of magnesium silicate, used as a dusting powder.

Back  -    New Search

talipes (tal-i-peez) n.

club-foot: a congenital deformity of one or both feet in which the patient cannot stand with the sole of the foot flat on the ground. t. equino-varus the most common variety of talipes, in which the foot points downwards, the heel is inverted, and the forefoot twisted. t. valgus talipes in which the hind foot is twisted outwards. t. varus talipes in which the hind foot is turned inwards.

Back  -    New Search

talus (astragalus) (tay-ls) n.

the ankle bone. It forms part of the tarsus, articulating with the tibia above, the fibula to the side, and the calcaneus below.

Back  -    New Search

tamoxifen (tam-oks-i-fen) n.

a drug used in the treatment of breast cancer: it combines with hormone receptors in the tumour to inhibit the effect of oestrogens (see ANTI-OESTROGEN). Trade name: Nolvadex .

Back  -    New Search

tampon (tam-pon) n.

a pack of gauze, cotton wool, or other absorbent material used to plug a cavity or canal in order to absorb blood or secretions.

Back  -    New Search

tamponade (tam-pon-ayd) n.

1 the insertion of a tampon.

2 abnormal pressure on a part of the body; for example, as caused by the presence of excessive fluid between the pericardium and the heart.
Top

Back  -    New Search

tantalum (tant--lm) n.

a rare heavy metal used in surgery. Tantalum sutures and plates are used for repair of defects in the bones of the skull. Symbol: Ta.

Back  -    New Search

tapeworm (tayp-werm) n.

any of a group of flatworms that have a long thin ribbonlike body and live as parasites in the intestines of man and other vertebrates. The body of a tapeworm consists of a head (see SCOLEX), a short neck, and a chain of separate segments (see PROGLOTTIS). Man is the primary host for some tapeworms (see TAENIA). However, other genera are also medically important (see ECHINOCOCCUS).

Back  -    New Search

tapotement (ta-poht-mahn) n.

a technique used in massage in which a part of the body is struck rapidly and repeatedly with the hands.

Back  -    New Search

tapping (tap-ing) n.

see PARACENTESIS.

Back  -    New Search

tar (tar) n.

a blackish viscous liquid produced by the destructive distillation of pine wood (pine t. ) or coal (coal t. ), used in skin preparations to treat eczema and psoriasis. As a constituent of cigarettes, tar is known to have carcinogenic properties.

Back  -    New Search

tars- (tarso-) prefix

denoting 1 the ankle; tarsal bones.

2 the edge of the eyelid.
Top

Back  -    New Search

tarsal (tar-sl)

1 adj. relating to the bones of the ankle and foot (tarsus).

2 adj. relating to the eyelid, especially to its supporting tissue (tarsus). t. glands see MEIBOMIAN GLANDS.
Top

3 n. any of the bones forming the tarsus.
Top

Back  -    New Search

tarsalgia (tar-sal-ji) n.

aching pain arising from the tarsus in the foot.

Back  -    New Search

tarsectomy (tar-sek-tmi) n.

1 surgical excision of the tarsal bones of the foot.

2 surgical removal of a section of the tarsus of the eyelid.
Top

Back  -    New Search

tarsitis (tar-sy-tis) n.

inflammation of the eyelid.

Back  -    New Search

tarsorrhaphy (tars-o-rfi) n.

an operation in which the upper and lower eyelids are joined together. It is performed to protect the cornea or to allow a corneal injury to heal.

Back  -    New Search

tarsus (tar-ss) n. (pl. tarsi)

1 the seven bones of the ankle and proximal part of the foot (see illustration). The tarsus articulates with the metatarsals distally and with the tibia and fibula proximally.

2 the firm fibrous connective tissue that forms the basis of each eyelid.

Top

Back  -    New Search

tartar (tar-ter) n.

an obsolete term for calculus, the hard deposit that forms on the teeth.

Back  -    New Search

task allocation (tahsk al--kay-shn) n.

a method of organizing nursing care in which patient care is divided into a number of tasks and a series of nurses is allocated to perform these tasks, on the basis of seniority. The patient thus receives fragmented care in which the emphasis is on the tasks (rather than the patient), which prevents holistic care and the development of a therapeutic relationship between patient and nurse. Compare PATIENT ALLOCATION.

Back  -    New Search

taste (tayst) n.

the sense for the appreciation of the flavour of substances in the mouth. There are four basic taste sensations – sweet, bitter, sour, and salt. t. buds the sensory receptors concerned with the sense of taste. They are located in the epithelium that covers the surface of the tongue and in the soft palate, the epiglottis, and parts of the pharynx. When a taste cell is stimulated by the presence of a dissolved substance impulses are sent via nerve fibres to the brain.

Back  -    New Search

taurine (tor-een) n.

an amino acid that is a constituent of the bile salt sodium tau-rocholate and also functions as a neurotransmitter in the central nervous system.

Back  -    New Search

taurocholic acid (tor-oh-koh-lik) n.

see BILE ACIDS.

Back  -    New Search

taxis (tak-sis) n.

(in surgery) the returning to a normal position of displaced bones, organs, or other parts by manipulation only.

Back  -    New Search

Taxol (taks-ol) n.

see PACLITAXEL.

Back  -    New Search

Tay-Sachs disease (amaurotic familial idiocy) (tay-saks) n.

an inherited disorder of lipid metabolism (see LIPIDOSIS) in which abnormal accumulation of lipid in the brain leads to blindness, mental retardation, and death in infancy. [W. Tay (1843–1927), British physician; B. Sachs (1858–1944), US neurologist]

Back  -    New Search

T bandage n.

a T-shaped bandage used for the perineum and sometimes the head.

Back  -    New Search

T-cell n.

a type of lymphocyte that matures in the thymus and is primarily responsible for cell-mediated immunity. cytotoxic T-c. (killer cell ) a T-cell that recognizes foreign antigen on the surface of target cells and destroys these cells by releasing cytolytic proteins. helper T-c . a T-cell that is involved in the recognition of foreign antigen on the surface of target cells and stimulates the production of cytotoxic T-cells. suppressor T-c . a T-cell that prevents an immune response by other T-cells or B-cells to an antigen.

Back  -    New Search

TCP n.

Trade name. a solution of trichlorphenol: an effective antiseptic for minor skin injuries and irritations. It may also be used as a gargle for colds and sore throats.

Back  -    New Search

team nursing (teem) n.

a method of organizing nursing care in which a team of nurses is responsible for the assessment, planning, implementation, and evaluation of a patient's hospital stay and subsequent discharge from the hospital.

Back  -    New Search

tears (teerz) pl. n.

the fluid secreted by the lacrimal glands to keep the front of the eyeballs moist and clean. Tears contain lysozyme, an enzyme that destroys bacteria.

Back  -    New Search

technetium-99 (tek-nee-shi-m) n.

an isotope of the artificial radioactive element technetium. It emits gamma radiation and is used as a tracer in the technique of scintigraphy (see SCINTIGRAM).

Back  -    New Search

tectospinal tract (tek-toh-spy-nl) n.

a tract that conveys nerve impulses from the midbrain to the spinal cord in the cervical (neck) region.

Back  -    New Search

tectum (tek-tm) n.

the roof of the mid-brain, behind and above the cerebral aqueduct.

Back  -    New Search

teeth (teeth) pl. n.

see TOOTH.

Back  -    New Search

tegmen (teg-mn) n. (pl. tegmina)

a structure that covers an organ or part of an organ.

Back  -    New Search

tegmentum (teg-men-tm) n.

the region of the midbrain below and in front of the cerebral aqueduct.

Back  -    New Search

tel- (tele-, telo-)prefix

denoting 1 end or ending.

2 distance.
Top

Back  -    New Search

tela (tee-l) n.

any thin weblike tissue. t. choroidea a folded double layer of pia mater containing numerous small blood vessels that extends into several of the ventricles of the brain.

Back  -    New Search

telangiectasis (til-an-ji-ek-t-sis) n. (pl. telangiectases)

a localized collection of distended blood capillary vessels. It is recognized as a red spot, sometimes spidery in appearance, that blanches on pressure. Telangiectases may be found in the skin or the lining of the mouth, gastrointestinal, respiratory, and urinary passages.

Back  -    New Search

teleceptor (tel-i-sep-ter) n.

a sensory receptor that is capable of responding to distant stimuli.

Back  -    New Search

telecurietherapy (tel-i-kewr-i-th'e-r-pi) n.

a form of radiotherapy in which penetrating radiation is directed at a patient from a distance.

Back  -    New Search

telencephalon (tel-en-sef--lon) n.

see CEREBRUM.

Back  -    New Search

teleradiology (tel-i-ray-di-ol-ji) n.

the process of transmitting and receiving medical images, to and from distant sites, using the telephone network. This requires a specialized link, such as an ISDN line, that has greater capacity for data transfer than standard telephone lines.

Back  -    New Search

telogen (tel-oh-jn) n.

see ANAGEN.

Back  -    New Search

temazepam (te-maz--pam) n.

a benzodiazepine given by mouth in the treatment of insomnia associated with difficulty falling asleep, frequent nocturnal awakenings, or early morning awakening. Trade name: Normison .

Back  -    New Search

temple (tem-pl) n.

the region of the head in front of and above each ear.

Back  -    New Search

temporal (temp-er-l) adj.

of or relating to the temple. t. arteritis see ARTERITIS. t. artery a branch of the external carotid artery that supplies blood mainly to the temple and scalp. t. bone either of a pair of bones of the cranium. The squamous portion forms part of the side of the cranium. The petrous part contributes to the base of the skull and contains the middle and inner ears. See also SKULL. t. lobe one of the main divisions of the cerebral cortex in each hemisphere of the brain, lying at the side within the temple. Areas of the cortex in this lobe are concerned with the appreciation of sound and spoken language. t. lobe epilepsy see EPILEPSY.

Back  -    New Search

temporalis (tem-per-ay-lis) n.

a fan-shaped muscle at the side of the head, extending from the temporal fossa to the mandible. This muscle lifts the lower jaw.

Back  -    New Search

temporo- prefix

denoting 1 the temple.

2 the temporal lobe of the brain.
Top

Back  -    New Search

temporomandibular joint (tem-per-oh-man-dib-yoo-ler) n.

the articulation between the mandible and the temporal bone. t. j. syndrome a condition in which the patient has painful temporomandibular joints, tenderness in the muscles that move the jaw, clicking of the joints, and limitation of jaw movement.

Back  -    New Search

tenaculum (tin-ak-yoo-lm) n.

1 a sharp wire hook with a handle, used in surgical operations to pick up pieces of tissue or the cut end of an artery.

2 a band of fibrous tissue that holds a part of the body in place.
Top

Back  -    New Search

tendinitis (ten-di-ny-tis) n.

inflammation of a tendon. It occurs most commonly after excessive overuse but is sometimes due to bacterial infection (e.g. gonorrhoea) or a generalized rheumatic disease (e.g. rheumatoid arthritis, ankylosing spondylitis). See also JUMPER'S KNEE, TENNIS ELBOW. Compare TENOSYNOVITIS.

Back  -    New Search

tendon (ten-dn) n.

a tough whitish cord, consisting of numerous parallel bundles of collagen fibres, that serves to attach a muscle to a bone. Tendons assist in concentrating the pull of the muscle on a small area of bone. t. sheath a tubular sac, lined with synovial membrane and containing synovial fluid, that surrounds some tendons. See also APONEUROSIS. t. transfer plastic surgery in which the tendon from an unimportant muscle is used to replace the damaged tendon of an important muscle.
—tendinous (ten-din-s) adj.

Back  -    New Search

tendovaginitis (tenovaginitis) (ten-doh-vaj-i-ny-tis) n.

inflammatory thickening of the fibrous sheath containing one or more tendons, usually caused by repeated minor injury. It usually occurs at the back of the thumb (de Quervain's t. ) and results in pain on using the wrists.

Back  -    New Search

tenesmus (tin-ez-ms) n.

a sensation of the desire to defecate, which is continuous or recurs frequently, without the production of significant amounts of faeces. It may be due to proctitis, prolapse of the rectum, rectal tumour, or irritable bowel syndrome.

Back  -    New Search

tennis elbow (ten-iss) n.

a painful inflammation of the tendon at the outer border of the elbow, caused by overuse of the forearm muscles. See also TENDINITIS. Compare GOLFER'S ELBOW.

Back  -    New Search

teno- prefix

denoting a tendon.

Back  -    New Search

Tenon's capsule (t-nonz) n.

the fibrous tissue that lines the orbit and surrounds the eyeball. [J. R. Tenon (1724–1816), French surgeon]

Back  -    New Search

tenoplasty (ten-oh-plasti) n.

surgical repair of a ruptured or severed tendon.

Back  -    New Search

tenoposide (te-nop-oh-syd) n.

a drug used in the treatment of certain cancers, particularly in childhood. It is very similar to etoposide.

Back  -    New Search

tenorrhaphy (tn-o-rfi) n.

the surgical operation of uniting the ends of divided tendons by suture.

Back  -    New Search

tenosynovitis (peritendinitis) (ten-oh-sy-noh-vy-tis) n.

inflammation of a tendon sheath, producing pain, swelling, and an audible creaking on movement. It may result from a bacterial infection or occur as part of a rheumatic disease.

Back  -    New Search

tenotomy (t-not-mi) n.

surgical division of a tendon. This may be necessary to correct a joint deformity caused by tendon shortening.

Back  -    New Search

tenovaginitis (ten-oh-vaj-i-ny-tis) n.

see TENDOVAGINITIS.

Back  -    New Search

TENS n.

transcutaneous electrical nerve stimulation: see STIMULATOR.

Back  -    New Search

tensor (ten-ser) n.

any muscle that causes stretching or tensing of a part of the body.

Back  -    New Search

tent (tent) n.

1 an enclosure of material (usually transparent plastic) around a patient in bed, into which a gas or vapour can be passed as part of treatment. oxygen t. a tent into which oxygen is passed.

2 a piece of dried vegetable material, usually a seaweed stem, shaped to fit into an orifice, such as the cervical canal. As it absorbs moisture it expands, dilating the orifice.
Top

Back  -    New Search

tentorium (ten-tor-im) n.

a curved infolded sheet of dura mater that separates the cerebellum below from the occipital lobes of the cerebral hemispheres above.

Back  -    New Search

terat- (terato-) prefix

denoting a monster or congenital abnormality.

Back  -    New Search

teratogen (te-r-toh-jen) n.

any substance, agent, or process that induces the formation of developmental abnormalities in a fetus. Known teratogens include the drug thalidomide, German measles, and irradiation with X-rays. Compare MUTAGEN. —teratogenic adj.

Back  -    New Search

teratogenesis (te-r-toh-jen-i-sis) n.

the process leading to developmental abnormalities in the fetus.

Back  -    New Search

teratology (te-r-tol-ji) n.

the study of developmental abnormalities and their causes.

Back  -    New Search

teratoma (te-r-toh-m) n.

a tumour composed of a number of tissues not usually found at that site. Teratomas most frequently occur in the testis and ovary, possibly derived from remnants of embryological cells.

Back  -    New Search

teratospermia (te-r-toh-sper-mi) n.

the presence in the semen of many bizarre or immature forms of spermatozoa, revealed by seminal analysis.

Back  -    New Search

terbinafine (ter-bin--feen) n.

an antifungal drug used to treat severe ringworm (see TINEA). It is administered by mouth. Trade name: Lamisil .

Back  -    New Search

terbutaline (ter-bew-t-leen) n.

a bron-chodilator drug (see SYMPATHOMIMETIC) administered by mouth, injection, or inhalation in the treatment of asthma, bronchitis, and other respiratory disorders. Trade name: Bricanyl .

Back  -    New Search

teres (te-reez) n.

either of two muscles of the shoulder, extending from the scapula to the humerus. t. major the muscle that rotates the arm inwards. t. minor the muscle that rotates the arm outwards.

Back  -    New Search

terfenadine (ter-fen--deen) n.

an antihistamine used for the treatment of the symptoms of hay fever, such as sneezing, itching, and watering of the eyes. It is administered by mouth. Trade name: Triludan .

Back  -    New Search

terlipressin (ter-li-pres-in) n.

a drug that releases vasopressin over a period of hours. It is used to help control bleeding from oesophageal varices.

Back  -    New Search

Terramycin (te-r-my-sin) n.

see OXYTETRACYCLINE.

Back  -    New Search

tertian fever (ter-shn) n.

a type of malaria, caused by Plasmodium ovale or P. vivax, in which there is a two-day interval between fever attacks.

Back  -    New Search

tertiary health care (ter-sher-i) n.

the services provided by specialized hospitals equipped with diagnostic and treatment facilities not available at general hospitals or by doctors who are uniquely qualified to treat unusual disorders that do not respond to therapy that is available at secondary care centres. Compare PRIMARY HEALTH CARE, SECONDARY HEALTH CARE.

Back  -    New Search

test (test) n.

a laboratory examination or chemical analysis to determine the presence of a specific substance, microorganism, disease, etc. (See individual entries for named tests.)

Back  -    New Search

testicle (test-ikl) n.

either of the pair of male sex organs within the scrotum. It consists of the testis and its system of ducts (the vasa efferentia and epididymis).

Back  -    New Search

testis (tes-tis) n. (pl. testes)

either of the pair of male sex organs that produce spermatozoa and secrete the male sex hormone androgen under the control of gonadotrophins from the pituitary gland. The testes are contained within the scrotum (see REPRODUCTIVE SYSTEM). See also SPERMATOGENESIS.

Back  -    New Search

test meal n.

a standard meal given to stimulate secretion of digestive juices, which can then be withdrawn by tube and measured as a test of digestive function. fractional t. m. a gruel preparation to stimulate gastric secretion. This test has been replaced by tests using histamine or pentagastrin as secretory stimulants.

Back  -    New Search

testosterone (test-ost-er-ohn) n.

the principal male sex hormone (see ANDROGEN).

Back  -    New Search

test-tube baby (test-tewb) n.

see IN VITRO FERTILIZATION.

Back  -    New Search

tetan- (tetano-) prefix

denoting 1 tetanus.

2 tetany.
Top

Back  -    New Search

tetanus (lockjaw) (tet-n-s) n.

an acute infectious disease, affecting the nervous system, caused by the bacterium Clostridium tetani. Infection occurs by contamination of wounds by bacterial spores. Symptoms consist of muscle stiffness, spasm, and subsequent rigidity, first in the jaw and neck then in the back, chest, abdomen, and limbs; in severe cases the spasm may affect the whole body, which is arched backwards (see OPISTHOTONOS). Prompt treatment with penicillin and antitoxin is effective; immunization against tetanus is effective but temporary.
—tetanic (t-tan-ik) adj.

Back  -    New Search

tetany (tet-n-i) n.

spasm and twitching of the muscles, particularly those of the face, hands, and feet. Tetany is caused by a reduction in the blood calcium level, which may be due to underactive parathyroid glands, rickets, or alkalosis.

Back  -    New Search

tetra- prefix

denoting four.

Back  -    New Search

tetracycline (tet-r-sy-kleen) n.

1 one of a group of antibiotic compounds derived from cultures of Streptomyces bacteria. These drugs, including chlortetracycline, oxytetracycline, and tetracycline, are effective against a wide range of bacterial infections, including respiratory tract infections, syphilis, and acne. They are usually given by mouth.

2 a particular antibiotic of the tetracycline group. Trade names: Achromycin , Tetrabid .
Top

Back  -    New Search

tetradactyly (tet-r-dak-tili) n.

a congenital abnormality in which there are only four digits on a hand or foot.
—tetradactylous adj.

Back  -    New Search

tetrahydrocannabinol (tet-r-hy-droh-kan-ab-in-ol) n.

a derivative of marijuana that has antiemetic activity and also produces euphoria. These two properties are utilized in the prevention of chemotherapy-induced sickness.

Back  -    New Search

tetralogy of Fallot (te-tral-ji v fa-loh) n.

a form of congenital heart disease in which there is pulmonary stenosis, enlargement of the right ventricle, and a ventricular septal defect over which the origin of the aorta lies. The affected child is blue (cyanosed). [E. L. A. Fallot (1850–1911), French physician]

Back  -    New Search

tetraplegia (tet-r-plee-ji) n.

see QUADRIPLEGIA.

Back  -    New Search

thalam- (thalamo-) prefix

denoting the thalamus.

Back  -    New Search

thalamencephalon (thal-m-en-sef--lon) n.

the structures, collectively, at the anterior end of the brainstem, comprising the epithalamus, thalamus, hypothalamus, and subthalamus.

Back  -    New Search

thalamic syndrome (th-lam-ik) n.

a condition resulting from damage to the thalamus, often by a stroke, that is characterized by severe intractable pain and hypersensitivity in the area of the body served by the damaged brain region.

Back  -    New Search

thalamotomy (thal--mot-mi) n.

an operation on the brain in which a lesion is made in a precise part of the thalamus. It has been used to control psychiatric symptoms of severe anxiety and distress. See also PSYCHOSURGERY.

Back  -    New Search

thalamus (thal--ms) n. (pl. thalami)

one of two egg-shaped masses of grey matter that lie deep in the cerebral hemispheres in each side of the forebrain. The thalami are relay stations for all the sensory messages that enter the brain, before they are transmitted to the cortex.

Back  -    New Search

thalassaemia (Cooley's anaemia) (thal--see-mi) n.

a hereditary blood disease, widespread in the Mediterranean countries, Asia, and Africa, in which there is an abnormality in the protein part of the haemoglobin molecule. Symptoms include anaemia, enlargement of the spleen, and abnormalities of the bone marrow. Individuals inheriting the disease from both parents are severely affected (t. major ), but those inheriting it from only one parent are usually symptom-free.

Back  -    New Search

thalidomide (th-lid--myd) n.

a drug that was formerly used as a sedative. If taken during the first three months of pregnancy, it was found to cause fetal abnormalities involving limb malformation.

Back  -    New Search

thallium scan (thal-im) n.

a method of studying blood flow through the heart muscle (myocardium) and diagnosing myocardial ischaemia using an injection of the radioisotope thallium-201. Defects of perfusion, such as a recent infarct, emit little or no radioactivity and are seen as ‘cold spots’ when an image is formed using a gamma camera and computer. Exercise may be used to provoke ‘cold spots’ in the diagnosis of ischaemic heart disease.

Back  -    New Search

theca (th'ee-k) n.

a sheathlike surrounding tissue.

Back  -    New Search

theine (th'ee-een) n.

the active volatile principle found in tea (seeCAFFEINE).

Back  -    New Search

thelarche (th'ee-lar-ki) n.

the process of breast development, which occurs as a normal part of puberty. Isolated premature breast development in girls is not uncommon and is almost always benign.

Back  -    New Search

thenar (th'ee-nar) n.

1 the palm of the hand.

2 the fleshy prominent part of the hand at the base of the thumb. Compare HYPOTHENAR.
Top

—thenar adj.

Back  -    New Search

theobromine (thi--broh-meen) n.

an alkaloid, occurring in cocoa, coffee, and tea, that has a weak diuretic action and dilates coronary and other arteries.

Back  -    New Search

theophylline (thi-off-i-leen) n.

an alkaloid, occurring in the leaves of the tea plant, that has a diuretic effect and relaxes smooth muscles. Theophylline preparations, particularly aminophylline, are used mainly to control bronchial asthma. Trade names: Lasma , Pro-Vent .

Back  -    New Search

therapeutic index (th'e-r-pew-tik) n.

the ratio of a dose of a therapeutic agent that produces damage to normal cells to the dose necessary to have a defined level of anticancer activity. It indicates the relative efficacy of a treatment against tumours.

Back  -    New Search

therapeutics (th'e-r-pew-tiks) n.

the branch of medicine that deals with different methods of treatment and healing (therapy ), particularly the use of drugs in the cure of disease.

Back  -    New Search

therm (therm) n.

a unit of heat equal to 100,000 British thermal units. 1 therm = 1.055 × 10^8 joules.

Back  -    New Search

therm- (thermo-) prefix

denoting 1 heat.

2 temperature.
Top

Back  -    New Search

thermoanaesthesia (therm-oh-anis-theez-i) n.

absence of the ability to recognize the sensations of heat and coldness. It may indicate damage to the spinothalamic tract in the spinal cord.

Back  -    New Search

thermocautery (therm-oh-kaw-ter-i) n.

the destruction of unwanted tissues by heat (see CAUTERIZE).

Back  -    New Search

thermocoagulation (therm-oh-koh-ag-yoo-lay-shn) n.

the coagulation and destruction of tissues by cautery.

Back  -    New Search

thermography (ther-mog-rfi) n.

a technique for measuring and recording the heat produced by different parts of the body, by using photographic film sensitive to infrared radiation. The picture produced is called a thermogram . A tumour with an abnormally increased blood supply may be revealed on the thermogram as a ‘hot spot’.

Back  -    New Search

thermolysis (ther-mol-i-sis) n.

(in physiology) the dissipation of body heat by such processes as the evaporation of sweat from the skin surface.

Back  -    New Search

thermometer (ther-mom-i-ter) n.

a device for registering temperature. clinical t. a sealed narrow-bore glass tube containing mercury, which expands when heated and rises up the tube. The tube is designed to register body temperatures between 35°C (95°F) and 43.5°C (110°F).

Back  -    New Search

thermophilic (therm-oh-fil-ik) adj.

describing organisms, especially bacteria, that grow best at temperatures of 48–85°C.

Back  -    New Search

thermoreceptor (therm-oh-ri-sep-ter) n.

a sensory nerve ending that responds to heat or to cold.

Back  -    New Search

thermotaxis (therm-moh-tak-sis) n.

the physiological process of regulating or adjusting body temperature.

Back  -    New Search

thermotherapy (therm-oh-th'e-r-pi) n.

the use of heat to alleviate pain and stiffness in joints and muscles and to promote an increase in circulation.

Back  -    New Search

thiabendazole (th'y--ben-d-zohl) n.

an anthelmintic administered orally to treat infestations of threadworms and other intestinal worms. Trade name: Mintezol .

Back  -    New Search

thiacetazone (thioparamizone) (th'y--set--zohn) n.

a drug, administered by mouth, that can be used in the treatment of tuberculosis (in combination with isoniazid).

Back  -    New Search

thiamin (vitamin B_1) (th'y--min) n.

see VITAMIN B.

Back  -    New Search

thiazide diuretic (th'y--zyd) n.

see DIURETIC.

Back  -    New Search

Thiersch's graft (split-skin graft) (teer-shz) n.

a type of skin graft in which thin partial thicknesses of skin are cut in narrow strips or sheets and placed onto the wound area to be healed. [K. Thiersch (1822–95), German surgeon]

Back  -    New Search

thigh (th'y) n.

the upper part of the lower limb, between the hip and the knee. t. bone see FEMUR.

Back  -    New Search

thioguanine (th'y-oh-gwah-neen) n.

a drug that prevents the growth of cancer cells and is administered by mouth in the treatment of leukaemia. Trade name: Lanvis .

Back  -    New Search

thioparamizone (th'y-oh-p-ram-i-zohn) n.

see THIACETAZONE.

Back  -    New Search

thiopentone (th'y-oh-pen-tohn) n.

a short-acting barbiturate. It is given by intravenous injection to produce general anaesthesia or as a premedication prior to surgery. Trade names: Intraval , Pentothal .

Back  -    New Search

thioridazine (th'y-oh-rid--zeen) n.

a phenothiazine antipsychotic drug administered by mouth in the treatment of a wide range of mental and emotional disturbances, including schizophrenia and senile dementia. Trade name: Melleril .

Back  -    New Search

Thomas's splint (tom--siz) n.

a metal splint used for immobilizing a fractured lower limb, especially the femur. There is a ring at the hip, a cross-piece at the foot, and side-pieces for the attachment of material to support the leg. [H. O. Thomas (1834–1931), British orthopaedic surgeon]

Back  -    New Search

thorac- (thoraco-) prefix

denoting the thorax or chest.

Back  -    New Search

thoracentesis (thor--sen-tee-sis) n.

see PLEUROCENTESIS.

Back  -    New Search

thoracic cavity (thor-ass-ik) n.

the chest cavity. See THORAX.

Back  -    New Search

thoracic duct n.

one of the two main trunks of the lymphatic system. It receives lymph from both legs, the lower abdomen, left thorax, left side of the head, and left arm and drains into the left innominate vein.

Back  -    New Search

thoracic vertebrae pl. n.

the 12 bones of the backbone to which the ribs are attached. See also VERTEBRA.

Back  -    New Search

thoracocentesis (thor--koh-sen-tee-sis) n.

see PLEUROCENTESIS.

Back  -    New Search

thoracoplasty (thor--koh-plasti) n.

a former treatment for pulmonary tuberculosis involving surgical removal of parts of the ribs, thus allowing the chest wall to fall in and collapse the affected lung.

Back  -    New Search

thoracoscope (thor--koh-skohp) n.

an instrument used to inspect the pleural cavity.
—thoracoscopy (thor--kosk-pi) n.

Back  -    New Search

thoracotomy (thor--kot-mi) n.

surgical opening of the chest cavity to inspect or operate on the heart, lungs, or other structures within.

Back  -    New Search

thorax (thor-aks) n.

the chest: the part of the body cavity between the neck and the diaphragm. The skeleton of the thorax is formed by the sternum, costal cartilages, ribs, and thoracic vertebrae. It encloses the lungs, heart, oesophagus, and associated structures. Compare ABDOMEN.
—thoracic adj.

Back  -    New Search

thorium-X (thor-im) n.

the radioactive isotope radium-224, which emits alpha radiation and was formerly used in radiotherapy. See also RADIUM.

Back  -    New Search

threadworm (pinworm) (thred-werm) n.

a parasitic nematode worm of the genus Enterobius (Oxyuris), which lives in the upper part of the large intestine of humans. Threadworms cause enterobiasis, a disease common in children throughout the world.

Back  -    New Search

threonine (three--neen) n.

an essential amino acid. See also AMINO ACID.

Back  -    New Search

threshold (thresh-ohld) n.

(in neurology) the point at which a stimulus begins to evoke a response, and therefore a measure of the sensitivity of a system under particular conditions.

Back  -    New Search

thrill (thril) n.

a vibration felt on placing the hand on the body.

Back  -    New Search

-thrix suffix

denoting a hair or hairlike structure.

Back  -    New Search

thromb- (thrombo-) prefix

denoting 1 a blood clot (thrombus).

2 thrombosis.
Top

3 blood platelets.
Top

Back  -    New Search

thrombectomy (throm-bek-tmi) n.

a surgical procedure in which a blood clot (thrombus) is removed from an artery or a vein (see ENDARTERECTOMY, PHLEBOTHROMBOSIS).

Back  -    New Search

thrombin (throm-bin) n.

a substance (coagulation factor) that acts as an enzyme, converting the soluble protein fibrinogen to the insoluble protein fibrin in the final stage of blood coagulation. Thrombin is derived from the inactive substance prothrombin.

Back  -    New Search

thromboangiitis obliterans (throm-boh-an-ji-l-tis -blit-er-anz) n.

see BUERGER'S DISEASE.

Back  -    New Search

thromboarteritis (throm-boh-ar-ter-l-tis) n.

inflammation of an artery (see ARTERITIS) associated with thrombosis.

Back  -    New Search

thrombocyte (throm-boh-syt) n.

see PLATELET.

Back  -    New Search

thrombocythaemia (throm-boh-si-th'ee-mi) n.

a disease in which there is an abnormal proliferation of megakaryocytes, leading to an increased number of platelets in the blood.

Back  -    New Search

thrombocytopenia (throm-boh-sy-toh-pee-ni) n.

a reduction in the number of platelets in the blood. This results in bleeding into the skin (see PURPURA), spontaneous bruising, and prolonged bleeding after injury.
—thrombocytopenic adj.

Back  -    New Search

thrombocytosis (throm-boh-sy-toh-sis) n.

an increase in the number of platelets in the blood. It may occur in a variety of diseases, including cancers and certain blood diseases, and is likely to cause an increased tendency to thrombosis.

Back  -    New Search

thromboembolism (throm-boh-em-b-lizm) n.

the condition in which a blood clot (thrombus), formed at one point in the circulation, becomes detached and lodges at another point.

Back  -    New Search

thromboendarterectomy (throm-boh-end-ar-ter-ek-tmi) n.

see ENDARTERECTOMY.

Back  -    New Search

thromboendarteritis (throm-boh-end-ar-ter-l-tis) n.

thrombosis complicating endarteritis, seen in temporal arteritis, polyarteritis nodosa, and syphilis.

Back  -    New Search

thrombokinase (throm-boh-ky-nayz) n.

see THROMBOPLASTIN.

Back  -    New Search

thrombolysis (throm-bol-i-sis) n.

the dissolution of a blood clot (thrombus) by the infusion of an enzyme, such as streptokinase or urokinase, into the blood.

Back  -    New Search

thrombolytic (throm-boh-lit-ik) adj.

describing an agent that breaks up blood clots (thrombi). See FIBRINOLYTIC, TISSUE PLASMINOGEN ACTIVATOR.

Back  -    New Search

thrombophlebitis (throm-boh-fli-by-tis) n.

inflammation of the wall of a vein (see PHLEBITIS) with secondary thrombosis occurring within the affected segment of vein. Pregnant women are more prone to thrombophlebitis because of physiological changes in the blood and the effects of pressure within the abdomen. It may involve superficial or deep veins of the legs (the latter being less common in pregnancy than the former).

Back  -    New Search

thromboplastin (thrombokinase) (throm-boh-plast-in) n.

a substance formed during the earlier stages of blood coagulation. It acts as an enzyme, converting the inactive substance prothrombin to the enzyme thrombin.

Back  -    New Search

thrombopoiesis (throm-boh-poi-ee-sis) n.

the process of blood platelet production. Platelets are formed as fragments of cytoplasm shed from giant cells (megakaryocytes) in the bone marrow by a budding process.

Back  -    New Search

thrombosis (throm-boh-sis) n.

a condition in which the blood changes from a liquid to a solid state and produces a blood clot (thrombus ). Thrombosis in an artery obstructs the blood flow to the tissue it supplies (see CORONARY THROMBOSIS, STROKE). Thrombosis can also occur in a vein (deep vein t. ; see PHLEBOTHROMBOSIS), and it may be associated with inflammation (see THROMBOPHLEBITIS).

Back  -    New Search

thrombus (throm-bs) n.

a blood clot (see THROMBOSIS).

Back  -    New Search

thrush (thrush) n.

see CANDIDOSIS.

Back  -    New Search

thumb (thum) n.

the first digit on the radial side of the hand. It can oppose the other four fingers of the hand.

Back  -    New Search

thym- (thymo-) prefix

denoting the thymus.

Back  -    New Search

thymectomy (th'y-mek-tmi) n.

surgical removal of the thymus gland.

Back  -    New Search

-thymia suffix

denoting a condition of the mind.

Back  -    New Search

thymine (th'y-meen) n.

one of the nitrogen-containing bases (see PYRIMIDINE) occurring in the nucleic acids DNA and RNA.

Back  -    New Search

thymitis (th'y-my-tis) n.

inflammation of the thymus gland.

Back  -    New Search

thymocyte (th'y-moh-syt) n.

a lymphocyte within the thymus.

Back  -    New Search

thymol (th'y-mol) n.

an antiseptic active against bacteria and fungi, used in mouth-washes, gargles, and skin preparations.

Back  -    New Search

thymoma (th'y-moh-m) n.

a benign or malignant tumour of the thymus gland. It is sometimes associated with myasthenia gravis.

Back  -    New Search

thymoxamine (th'y-moks--meen) n.

an alpha-blocker drug that causes peripheral blood vessels to dilate (see VASODILATOR). It is administered by mouth in the treatment of Raynaud's disease and similar conditions. Trade name: Opilon .

Back  -    New Search

thymus (th'y-ms) n.

a bilobed organ in the root of the neck, above and in front of the heart. In relation to body size the thymus is largest at birth. It doubles in size by puberty, after which it gradually shrinks, its functional tissue being replaced by fatty tissue. In infancy the thymus controls the development of lymphoid tissue and immune response to microbes and foreign proteins. Its function in the adult is unclear.
—thymic adj.

Back  -    New Search

thyro- prefix

denoting the thyroid gland.

Back  -    New Search

thyrocalcitonin (th'y-roh-kal-si-toh-nin) n.

see CALCITONIN.

Back  -    New Search

thyrocele (th'y-roh-seel) n.

a swelling of the thyroid gland. See GOITRE.

Back  -    New Search

thyroglobulin (th'y-roh-glob-yoo-lin) n.

a protein in the thyroid gland from which the thyroid hormones are synthesized.

Back  -    New Search

thyroglossal (th'y-roh-glos-l) adj.

relating to the thyroid gland and the tongue. t. duct a duct in the embryo between the thyroid and the back of the tongue.

Back  -    New Search

thyroid cartilage (th'y-roid) n.

the main cartilage of the larynx, consisting of two broad plates that join at the front. See also ADAM'S APPLE.

Back  -    New Search

thyroidectomy (th'y-roid-ek-tmi) n.

surgical removal of the thyroid gland. partial t. thyroidectomy in which only the diseased part of the gland is removed. subtotal t. a method of treating thyrotoxicosis, in which the surgeon removes 90% of the gland.

Back  -    New Search

thyroid gland n.

a large endocrine gland situated in the base of the neck. It consists of two lobes, one on either side of the trachea, that are joined by an isthmus. The thyroid gland is concerned with regulation of the metabolic rate by the secretion of thyroid hormone. Thyroid extract is used in the treatment of thyroid deficiency diseases. The C cells of the thyroid gland secrete calcitonin.

Back  -    New Search

thyroid hormone n.

an iodine-containing substance, synthesized and secreted by the thyroid gland, that is essential for normal metabolic processes and mental and physical development. There are two thyroid hormones, triiodothyronine and thyroxine . Lack of these hormones gives rise to cretinism in infants and myxoedema in adults. Excessive production of thyroid hormones gives rise to thyrotoxicosis.

Back  -    New Search

thyroiditis (th'y-roid-l-tis) n.

inflammation of the thyroid gland. acute t. thyroiditis due to bacterial infection. chronic t. thyroiditis that is commonly caused by an abnormal immune response (see AUTOIMMUNITY) in which lymphocytes invade the tissues of the gland. See HASHIMOTO'S DISEASE.

Back  -    New Search

thyroid-stimulating hormone (TSH, thyrotrophin) n.

a hormone, synthesized and secreted by the anterior pituitary gland under the control of thyrotrophin-releasing hormone, that stimulates activity of the thyroid gland.

Back  -    New Search

thyroplasty (th'y-roh-plasti) n.

a surgical procedure performed on the thyroid cartilage of the larynx to alter the characteristics of the voice.

Back  -    New Search

thyrotomy (th'y-rot-mi) n.

surgical incision of either the thyroid cartilage or the thyroid gland itself.

Back  -    New Search

thyrotoxicosis (th'y-roh-toks-i-koh-sis) n.

the syndrome due to excessive amounts of thyroid hormones in the bloodstream, causing a rapid heartbeat, sweating, tremor, anxiety, increased appetite, loss of weight, and intolerance of heat. Causes include simple overactivity of the gland, a hormone-secreting tumour, and Graves' disease (exophthalmic goitre ), in which there are additional symptoms including swelling of the neck (goitre) and protrusion of the eyes (exophthalmos).
—thyrotoxic adj.

Back  -    New Search

thyrotrophin (th'y-roh-troh-fin) n.

see THYROID-STIMULATING HORMONE.

Back  -    New Search

thyrotrophin-releasing hormone (TRH) n.

a hormone that is secreted from the hypothalamus (in the brain) and acts on the anterior pituitary gland to stimulate the release of thyroid-stimulating hormone.

Back  -    New Search

thyroxine (th'y-roks-een) n.

see THYROID HORMONE.

Back  -    New Search

TIA n.

see TRANSIENT ISCHAEMIC ATTACK.

Back  -    New Search

tibia (tib-i) n.

the shin bone: the inner and larger bone of the lower leg. It articulates with the femur above, with the talus below, and with the fibula to the side.
—tibial adj.

Back  -    New Search

tibialis (tib-i-ay-lis) n.

either of two muscles in the leg, extending from the tibia to the metatarsal bones of the foot. t. anterior the muscle that turns the foot inwards and flexes the toes backwards. t. posterior the muscle that extends the toes and inverts the foot.

Back  -    New Search

tibial torsion (tib-il) n.

a normal variation in posture in which there is an in-toe gait due to mild internal rotation of the tibia. The condition is often apparent in infancy when the child starts walking and resolves spontaneously with time.

Back  -    New Search

tibio- prefix

denoting the tibia.

Back  -    New Search

tic (tik) n.

a repeated and largely involuntary movement varying in complexity from the twitch of a muscle to elaborate well-coordinated actions. Simple tics occur in about a quarter of children and usually disappear within a year. See also GILLES DE LA TOURETTE SYNDROME. t. douloureux see NEURALGIA.

Back  -    New Search

ticaricillin (ti-ka-ri-sil-in) n.

a penicillin-type antibiotic useful for its action against the bacterium Pseudomonas aeruginosa.

Back  -    New Search

tick (tik) n.

a bloodsucking parasite belonging to the order of arthropods (Acarina) that also includes the mites. Tick bites can cause serious skin lesions and occasionally paralysis, and certain tick species transmit typhus, Lyme disease, and relapsing fever. Dimethyl phthalate is used as a tick repellent. t. fever any infectious disease transmitted by ticks, especially Rocky Mountain spotted fever.

Back  -    New Search

timolol (tim--lol) n.

a beta blocker used in the treatment of high blood pressure (hypertension), long-term prophylaxis after an acute myocardial infarction, and glaucoma. It is administered by mouth or in solution as eye drops. Trade names: Betim , Blocadren , Timoptol .

Back  -    New Search

tincture (tink-cher) n.

an alcoholic extract of a drug derived from a plant.

Back  -    New Search

tinea (ringworm) (tin-i) n.

a fungus infection of the skin, scalp, or nails. It is caused by the dermatophyte fungi – Microsporum, Trichophyton, and Epidermophyton – and can be spread by direct contact or via infected materials. The lesions of ringworm may be ringlike and may cause intense itching. The disease is treated with antifungal agents taken by mouth (such as itraconazole or terbinafine) or applied locally. t. barbae ringworm of the skin under a beard. t. capitis ringworm of the scalp, of which favus is a severe form. t. cruris see DHOBIE ITCH. t. pedis see ATHLETE'S FOOT.

Back  -    New Search

Tinel's sign (ti-nelz) n.

a method for checking the regeneration of a nerve: direct tapping over the sheath of the nerve elicits a distal tingling sensation (see PARAESTHESIAE), which indicates the beginning of regeneration. [J. Tinel (1879–1952), French neurologist]

Back  -    New Search

tinnitus (ti-ny-ts) n.

the sensation of sounds in the ears or head in the absence of an external sound source. The most common cause is age-related hair-cell loss in the cochlea. Other causes include wax in the ear canal, diseases of the inner ear, and drugs such as aspirin or quinine. t. masker see WHITE NOISE INSTRUMENT.

Back  -    New Search

tintometer (tin-tom-it-er) n.

an instrument for measuring the depth of colour in a liquid. The colour can then be compared with those on standard charts so that the concentration of a particular compound in solution can be estimated.

Back  -    New Search

tissue (tis-yoo) n.

a collection of cells specialized to perform a particular function. Aggregations of tissues constitute organs. t. culture the culture of living tissues, removed from the body, in a suitable medium supplied with nutrients and oxygen. t. typing determination of the HLA profiles of tissues (see HLA SYSTEM) to assess their compatibility. It is the most important predictor of success or failure of a transplant operation.

Back  -    New Search

tissue plasminogen activator (tPA, TPA) n.

a natural protein, found in the body and now able to be manufactured by genetic engineering, that can break up a thrombus (see THROMBOLYSIS). It requires the presence of fibrin as a cofactor and capable of activating plasminogen on the fibrin surface, which distinguishes it from the other plasminogen activators streptokinase and urokinase.

Back  -    New Search

titration (ty-tray-shn) n.

a method of determining the concentration of a substance in solution. A measured volume of a reagent of known concentration is added to a known volume of the test solution until the end point of the reaction has occurred.

Back  -    New Search

titre (ty-ter) n.

(in immunology) the extent to which a sample of blood serum containing antibody can be diluted before losing its ability to cause agglutination of the relevant antigen. It is used as a measure of the amount of antibody in the serum.

Back  -    New Search

T-lymphocyte n.

see LYMPHOCYTE; T-CELL.

Back  -    New Search

TNM classification n.

a classification defined by the American Joint Committee on Cancer for the extent of spread of a cancer. T refers to the size of the tumour, N the presence and extent of lymph node involvement, and M the presence of distant spread (metastasis).

Back  -    New Search

tobacco (t-bak-oh) n.

the dried leaves of the plant Nicotiana tabacum or related species, used in smoking and as snuff. Tobacco contains the stimulant but poisonous alkaloid nicotine, which enters the bloodstream during smoking. The volatile tarry material released during smoking contains carcinogenic chemicals.

Back  -    New Search

tobramycin (toh-br-my-sin) n.

an antibiotic used to treat septicaemia, external eye infections, and lower respiratory, urinary, skin, abdominal, and central nervous system infections. It is administered by intravenous or intramuscular injections or applied by ointment or solution to the eye. Trade names: Nebcin , Tobralex .

Back  -    New Search

tocainide (tok-ay-nyd) n.

an antiarrhythmic drug that is used to treat life-threatening cardiac arrest due to ventricular fibrillation. It is administered by mouth. Trade name: Tonocard .

Back  -    New Search

toco-prefix

denoting childbirth or labour.

Back  -    New Search

tocography (tok-og-rfi) n.

the measuring and recording of the force and frequency of uterine contractions during labour using an instrument called a tocodynamometer .

Back  -    New Search

tocopherol (tok-off-er-ol) n.

see VITAMIN E.

Back  -    New Search

toddler's diarrhoea (tod-lerz) n.

a disorder of young children characterized by the passage of frequent loose, offensive, and bulky stools in which partially digested or undigested food may be visible (the ‘peas and carrot’ stool). It resolves by school age.

Back  -    New Search

Todd's paralysis (Todd's palsy) (todz) n.

transient paralysis of a part of the body that has previously been involved in a focal epileptic seizure (see EPILEPSY). [R. B. Todd (1809–60), British physician]

Back  -    New Search

tolazamide (tol-az--myd) n.

a drug administered by mouth in the treatment of noninsulin-dependent diabetes mellitus. Trade name: Tolanase . See also SULPHONYLUREA.

Back  -    New Search

tolbutamide (tol-bew-t-myd) n.

a drug taken by mouth in the treatment of non-insulin-dependent diabetes mellitus. It acts directly on the pancreas to stimulate insulin production and is particularly effective in elderly patients with mild diabetes. Trade names: Pramidex , Rastinon . See also SULPHONYLUREA.

Back  -    New Search

tolerance (tol-er-ns) n.

the reduction or loss of the normal response to a substance that usually provokes a reaction in the body. drug t. tolerance that may develop after taking a particular drug over a long period of time. In such cases increased doses are necessary to produce the desired effect. See also GLUCOSE TOLERANCE TEST, IMMUNOLOGICAL TOLERANCE.

Back  -    New Search

tolnaftate (tol-naf-tayt) n.

an antiseptic applied topically as a cream, powder, or solution in the treatment of various fungal infections of the skin, including ringworm. Trade names: Tinactin , Tinaderm .

Back  -    New Search

-tome suffix

denoting a cutting instrument.

Back  -    New Search

tomo- prefix

denoting 1 section or sections.

2 surgical operation.
Top

Back  -    New Search

tomography (t-mog-rfi) n.

the technique of using a rotating source of X-rays to produce an image of structures at a particular depth within the body. The visual record of this technique is called a tomogram See also COMPUTERIZED TOMOGRAPHY, POSITRON EMISSION TOMOGRAPHY.

Back  -    New Search

-tomy (-otomy) suffix

denoting a surgical incision into an organ or part.

Back  -    New Search

tone (tohn) n.

see TONUS.

Back  -    New Search

tongue (tung) n.

a muscular organ attached to the floor of the mouth. It is covered by mucous membrane and its surface is raised in minute projections (papillae), which give it a furred appearance. Taste buds are arranged in grooves around the papillae. The tongue helps in manipulating food during mastication and swallowing; it is the main organ of taste; and it plays an important role in the production of articulate speech. Anatomical name: glossa .

Back  -    New Search

tongue-tie (tung-ty) n.

a disorder of young children in which the tongue is anchored in the floor of the mouth more firmly than usual. No treatment is required unless the condition is extreme and associated with forking of the tongue.

Back  -    New Search

tonic (ton-ik)

1 adj.
a relating to normal muscle tone.
b marked by continuous tension (contraction), e.g. a tonic muscle spasm. t. pupil (Adie's pupil ) a pupil that is dilated as a result of damage to the nerves supplying the ciliary muscle and iris.

2 n. a medicinal substance purporting to increase vigour and liveliness and produce a feeling of wellbeing: beneficial effects of tonics are probably due to their placebo action.
Top

Back  -    New Search

tonicity (toh-nis-iti) n.

1 the normal state of slight contraction, or readiness to contract, of healthy muscle fibres.

2 the effective osmotic pressure of a solution. See HYPERTONIC, HYPOTONIC, OSMOSIS.
Top

Back  -    New Search

tono-prefix

denoting 1 tone or tension.

2 pressure.
Top

Back  -    New Search

tonography (toh-nog-rfi) n.

measurement of the pressure within the eyeball in such a way as to record variations in pressure over a period of several minutes.

Back  -    New Search

tonometer (toh-nom-it-er) n.

an instrument for measuring pressure in a part of the body, e.g. the eye (see OPHTHALMOTONOMETER).

Back  -    New Search

tonsil (ton-sil) n.

a mass of lymphoid tissue on either side of the back of the mouth, between the anterior and posterior pillars of the fauces. The tonsils are concerned with protection against infection. See also ADENOIDS (NASOPHARYNGEAL TONSIL).

Back  -    New Search

tonsillectomy (ton-sil-ek-tmi) n.

surgical removal of the tonsils.

Back  -    New Search

tonsillitis (ton-sil-I-tis) n.

inflammation of the tonsils due to bacterial or viral infection, causing a sore throat, fever, and difficulty in swallowing.

Back  -    New Search

tonsillotome (ton-sil--tohm) n.

a surgical knife used for cutting into or removing a tonsil.

Back  -    New Search

tonus (tone) (toh-ns) n.

the normal state of partial contraction of a resting muscle.

Back  -    New Search

tooth (tooth) n. (pl. teeth)

one of the hard structures in the mouth used for cutting and chewing food. Each tooth is embedded in a socket in the jawbone, to which it is attached by the periodontal membrane. The exposed part of the tooth (crown ) is covered with enamel and the part within the bone (root ) is coated with cementum; the bulk of the tooth consists of dentine enclosing the pulp. There are four different types of teeth (see CANINE, INCISOR, PREMOLAR, MOLAR). See illustration. See also DENTITION.

Back  -    New Search

topagnosis (top-ag-noh-sis) n.

inability to identify a part of the body that has been touched. It is a symptom of disease in the parietal lobes of the brain.

Back  -    New Search

tophus (top-fs) n. (pl. tophi)

a hard deposit of crystalline uric acid and its salts in the skin, cartilage (especially of the ears), or joints: a feature of gout.

Back  -    New Search

topical (top-ikfi) adj.

local: used for the route of administration of a drug that is applied directly to the part being treated.

Back  -    New Search

topo-prefix

denoting place; position; location.

Back  -    New Search

topography (t-pog-rfi) n.

the study of the different regions of the body, including the description of its parts in relation to the surrounding structures.
—topographical (top--graf-ikl) adj.

Back  -    New Search

tormina (tor-min-) n.

see COLIC.

Back  -    New Search

torpor (tor-per) n.

a state of sluggishness and diminished responsiveness: a characteristic of certain mental disorders and a symptom of certain forms of poisoning or metabolic disorder.

Back  -    New Search

torsion (tor-shn) n.

twisting. See also TIBIAL TORSION.

Back  -    New Search

torticollis (wryneck) (tor-ti-kol-iss) n.

an irresistible turning movement of the head that becomes more persistent, so that eventually the head is held continually to one side. It may be caused by a birth injury to the sternomastoid muscle (see STERNOMASTOID TUMOUR).

Back  -    New Search

Tourette syndrome (toor-et) n.

see GILLES DE LA TOURETTE SYNDROME.

Back  -    New Search

tourniquet (toor-ni-kay) n.

a device to press upon an artery and prevent flow of blood through it, usually a cord, rubber tube, or tight bandage. Tourniquets are no longer recommended as a first-aid measure to stop bleeding from a wound; direct pressure on the wound itself is considered less harmful.

Back  -    New Search

tow (toh) n.

the teased-out short fibres of flax, hemp, or jute, used in swabs, stupes, and for a variety of other purposes.

Back  -    New Search

tox- (toxi-, toxo-, toxic(o)-) prefix

denoting 1 poisonous; toxic.

2 toxins or poisoning.
Top

Back  -    New Search

toxaemia (toks-eem-i) n.

blood poisoning that is caused by toxins formed by bacteria growing in a local site of infection. Compare PYAEMIA, SAPRAEMIA, SEPTICAEMIA.

Back  -    New Search

toxic (toks-ik) adj.

having a poisonous effect; potentially lethal.

Back  -    New Search

toxicity (toks-iss-iti) n.

the degree to which a substance is poisonous.

Back  -    New Search

toxicology (toks-i-kol-ji) n.

the study of poisonous materials and their effects upon living organisms.
—toxicologist n.

Back  -    New Search

toxicosis (toks-i-koh-sis) n.

the deleterious effects of a toxin; poisoning.

Back  -    New Search

toxic shock syndrome n.

a state of acute shock due to septicaemia. The commonest cause is a retained foreign body (e.g. a tampon or IUCD) combined with the presence of staphylococci. The condition can be life-threatening if not treated aggressively with appropriate antibiotics and supportive care (including fluid and electrolyte replacement). streptococcal t. s. s. a similar condition caused by Type A streptococci. See also NECROTIZING FASCIITIS.

Back  -    New Search

toxin (toks-in) n.

a poison produced by a living organism, especially by a bacterium (see ENDOTOXIN, EXOTOXIN). In the body toxins act as antigens (see ANTITOXIN).

Back  -    New Search

toxocariasis (visceral larva migrans) (toks-oh-kair-I--sis) n.

an infestation with the larvae of the dog and cat roundworms. Toxocara canis and T. cati. It is characterized by enlargement of the liver, pneumonitis, fever, joint and muscle pains, vomiting, an irritating rash, and convulsions.

Back  -    New Search

toxoid (toks-oid) n.

a preparation of a toxin that has been rendered harmless by chemical treatment while retaining its antigenic activity. Toxoids are used in vaccines.

Back  -    New Search

toxoid-antitoxin n.

a mixture of a toxoid and its antitoxin used as a vaccine to produce active immunity.

Back  -    New Search

toxoplasmosis (toks-oh-plaz-moh-sis) n.

a disease of mammals and birds due to the protozoan Toxoplasma gondii, which may be transmitted to humans (usually by eating undercooked infected meat or by contact with cat faeces). Generally symptoms are mild (swollen lymph nodes and an influenza-like illness), but the disease can be serious in immunocompromised patients. congenital t. toxoplasmosis transmitted by a woman infected during pregnancy to her fetus. It may produce severe malformations of the skull and eyes or active liver infection in the newborn.

Back  -    New Search

tPA (TPA) n.

see TISSUE PLASMINOGEN ACTIVATOR.

Back  -    New Search

trabecula (tr-bek-yoo-l) n.

(pl. trabeculae) 1 any of the bands of tissue that pass from the outer part of an organ to its interior, dividing it into separate chambers.

2 any of the thin bars of bony tissue in spongy bone.
Top

—trabecular adj.

Back  -    New Search

trabeculectomy (tr-bek-yoo-lek-tmi) n.

an operation for glaucoma, one part of which is the removal of a small segment of tissue from part of the wall of Schlemm's canal. This area is known as the trabecular meshwork . Trabeculectomy allows aqueous fluid to filter out of the eye under the conjunctiva, thus reducing the pressure inside the eye.

Back  -    New Search

trabeculoplasty (tr-bek-yoo-loh-plasti) n.

a method used to selectively destroy parts of the trabecular meshwork (see TRABECULECTOMY) and hence reduce intraocular pressure in the treatment of glaucoma. This may be achieved by means of a laser (argon laser t. ).

Back  -    New Search

trace element (trayss) n.

an element required in minute amounts for the normal functioning of the body. Examples are copper, cobalt, and manganese.

Back  -    New Search

tracer (tray-ser) n.

a substance that is introduced into the body and whose progress can subsequently be followed so that information is gained about metabolic processes. Radioactive tracers, which are substances labelled with radionuclides, are used for a variety of purposes, such as the investigation of thyroid disease or possible brain tumours.

Back  -    New Search

trache- (tracheo-) prefix

denoting the trachea.

Back  -    New Search

trachea (tray-ki) n.

the windpipe: the part of the air passage between the larynx and the main bronchi.
—tracheal (tray-ki-l) adj.

Back  -    New Search

tracheal tugging n.

a sign indicative of an aneurysm of the aortic arch: a downward tug is felt on the windpipe when the finger is placed in the midline at the root of the neck.

Back  -    New Search

tracheitis (tray-ki-I-tis) n.

inflammation of the trachea, usually secondary to bacterial or viral infection in the nose or throat. Tracheitis causes soreness in the chest and a painful cough and is often associated with bronchitis.

Back  -    New Search

trachelorrhaphy (tray-kl-o-rfi) n.

an operation for suturing tears in the cervix of the uterus.

Back  -    New Search

tracheobronchitis (tray-ki-oh-brong-ky-tis) n.

inflammation of the trachea and bronchi.

Back  -    New Search

tracheostomy (tracheotomy) (tray-ki-ost-mi) n.

a surgical operation in which a hole is made into the trachea through the neck to relieve obstruction to breathing, as in diphtheria. A curved metal, plastic, or rubber tube is usually inserted through the hole and held in position by tapes tied round the neck. See also MINITRACHEOSTOMY.

Back  -    New Search

tracheotomy (tray-ki-ot-mi) n.

see TRACHEOSTOMY.

Back  -    New Search

trachoma (tr-koh-m) n.

a chronic contagious eye disease -a severe form of conjunctivitis caused by the bacterium Chlamydia trachomatis — that is common in some hot countries. If untreated, the conjunctiva becomes scarred and shrinks, causing trichiasis; blindness can be a late complication. Treatment with tetracyclines is effective in the early stages of the disease.

Back  -    New Search

tract (trakt) n.

1 a group of nerve fibres passing from one part of the brain or spinal cord to another, forming a distinct pathway.

2 an organ or collection of organs providing for the passage of something, e.g. the digestive tract.
Top

Back  -    New Search

traction (trak-shn) n.

the application of a pulling force, especially as a means of counteracting the natural tension in the tissues surrounding a broken bone, to produce correct alignment of the fragments. Considerable force, exerted with weights, ropes, and pulleys, may be necessary to ensure that a broken femur is kept correctly positioned during the early stages of healing.

Back  -    New Search

tractotomy (trak-tot-mi) n.

a neurosurgical operation for the relief of intractable pain, in which the nerve fibres that carry painful sensation to consciousness are severed within the medulla oblongata. See also CORDOTOMY.

Back  -    New Search

tragus (tray-gs) n.

the projection of cartilage in the pinna of the outer ear that extends back over the opening of the external auditory meatus.

Back  -    New Search

trance (trahns) n.

a state in which reaction to the environment is diminished although awareness is not impaired. It may be caused by hypnosis, meditation, catatonia, conversion disorder, or drugs.

Back  -    New Search

tranexamic acid (tran-eks-am-ik) n.

an antifibrinolytic drug administered by mouth as an antidote to overdosage by fibrinolytic drugs and to control severe bleeding, for example in haemophiliacs. Trade name: Cyklokapron .

Back  -    New Search

tranquillizer (trank-wi-ly-zer) n.

a drug that produces a calming effect, relieving anxiety and tension. major t. see ANTIPSYCHOTIC. minor t. a drug, such as a benzodiazepine or meprobamate, used to treat neuroses and to relieve anxiety and tension. Dependence may occur with prolonged use.

Back  -    New Search

trans- prefix

denoting through or across.

Back  -    New Search

transaminase (trans-am-in-ayz) n.

an enzyme that is involved in the process of transamination. Examples are aspartate aminotransaminase (AST) and alanine aminotransaminase (ALT).

Back  -    New Search

transamination (trans-am-i-nay-shn) n.

a process involved in the metabolism of amino acids in which amino groups (-NH_2) are transferred from amino acids to certain -keto acids, with the production of a second keto acid and amino acid. The reaction is catalysed by transaminases.

Back  -    New Search

transcription (tran-skrip-shn) n.

the process in which the information contained in the genetic code is transferred from DNA to RNA: the first step in the manufacture of proteins in cells. See MESSENGER RNA, TRANSLATION.

Back  -    New Search

transcutaneous electrical nerve stimulation (TENS) (trans-kew-tay-nis) n.

see STIMULATOR.

Back  -    New Search

transdermal (trans-der-ml) adj.

through the skin: applied to the route of administration of drugs that are absorbed through the skin.

Back  -    New Search

transducer (trans-dew-ser) n.

a device used to convert one form of signal into another, allowing its measurement or display to be made appropriately. For example, an ultrasound probe converts reflected ultrasound waves into electronic impulses, which can be displayed on a TV monitor.

Back  -    New Search

transection (tran-sek-shn) n.

1 a cross section of a piece of tissue.

2 cutting across the tissue of an organ (see also SECTION).
Top

Back  -    New Search

transferase (trans-fer-ayz) n.

an enzyme that catalyses the transfer of a group (other than hydrogen) between a pair of substrates.

Back  -    New Search

transference (trans-fer-ns) n.

(in psychoanalysis) the process by which a patient comes to feel and act towards the therapist as though he or she were somebody from the patient's past life, especially a powerful parent. The patient's transference feelings may be of love or of hatred.

Back  -    New Search

transferrin (siderophilin) (trans-fer-in) n.

a glycoprotein, found in the blood plasma, that acts as a carrier for iron in the bloodstream.

Back  -    New Search

transfer RNA (trans-fer) n.

a type of RNA whose function is to attach the correct amino acid to the protein chain being synthesized at a ribosome. See also TRANSLATION.

Back  -    New Search

transfusion (trans-few-zhn) n.

1 the injection of a volume of blood obtained from a healthy person into the circulation of a patient whose blood is deficient in quantity or quality, through accident or disease. The blood is allowed to drip, under gravity, through a needle inserted into one of the patient's veins. Blood transfusion is routine during major surgical operations in which much blood is likely to be lost.

2 the administration of any fluid, such as plasma or saline solution, into a patient's vein by means of a drip.
Top

Back  -    New Search

transient ischaemic attack (TIA) (tranz-i-nt isk-ee-mik) n.

the result of temporary disruption of the circulation to part of the brain due to embolism, thrombosis to brain arteries, or spasm of the vessel walls. The symptoms may be similar to those of a stroke but patients recover within 24 hours.

Back  -    New Search

transillumination (tranz-i-loo-mi-nay-shn) n.

the technique of shining a bright light through part of the body to examine its structure.
Transillumination of the paranasal sinuses is a means of detecting abnormalities.

Back  -    New Search

translation (tranz-lay-shn) n.

(in cell biology) the manufacture of proteins in a cell, which takes place at the ribosomes. See MESSENGER RNA, TRANSFER RNA.

Back  -    New Search

translocation (tranz-loh-kay-shn) n.

(in genetics) a type of chromosome mutation in which part of a chromosome is transferred to another part of the same chromosome or to a different chromosome. This can lead to serious genetic disorders, e.g. chronic myeloid leukaemia.

Back  -    New Search

translumbar (tranz-lum-ber) adj.

through the lumbar region: describing the route for injecting the aorta for aortography.

Back  -    New Search

transmigration (tranz-my-gray-shn) n.

the act of passing through or across, e.g. the passage of blood cells through the intact walls of capillaries and venules (see DIAPEDESIS).

Back  -    New Search

transplacental (trans-pl-sen-t'l) adj.

across the placenta: describing the transport of substances, etc., between mother and fetus.

Back  -    New Search

transplantation (trans-plahn-tay-shn) n.

the implantation of an organ or tissue from one part of the body to another, as in skin or bone grafting, or from one person to another, as in kidney or heart transplants. Transplanting organs or tissues between individuals is a difficult procedure because of the natural rejection processes in the recipient of the graft. Special treatment (e.g. with immunosuppressive drugs) is needed to prevent graft rejection.

Back  -    New Search

transposition (trans-p-zish-n) n.

the abnormal positioning of a part of the body such that it is on the opposite side to its normal site in the body. t. of the great vessels a congenital abnormality of the heart in which the aorta arises from the right ventricle and the pulmonary artery from the left ventricle.

Back  -    New Search

transsexualism (tranz-seks-yoo-l-izm) n.

the condition of one who firmly believes that he (or she) belongs to the sex opposite to his (or her) biological gender. In adults surgical sex reassignment is sometimes justifiable, to make the externals of the body conform to the individual's view of himself (or herself).
—transsexual adj., n.

Back  -    New Search

transudation (trans-yoo-day-shn) n.

the passage of a liquid through a membrane, especially of blood through the wall of a capillary vessel. The liquid is called the transudate .

Back  -    New Search

transuretero-ureterostomy (trans-yoor-ee-ter-oh-yoor-i-ter-ost-mi) n.

the operation of connecting one ureter to the other in the abdomen. The damaged or obstructed ureter is cut above the diseased or damaged segment and joined end-to-side to the other ureter.

Back  -    New Search

transurethral (trans-yoor-ee-thrl) adj.

through the urethra. t. resection of the prostate see RESECTION.

Back  -    New Search

transvaginal (tranz-v-jy-nl) adj.

through or across the vagina. t. ultrasonography see ULTRASONOGRAPHY.

Back  -    New Search

transverse (tranz-vers) adj.

(in anatomy) situated at right angles to the long axis of the body or an organ. t. process the long projection from the base of the neural arch of a vertebra.

Back  -    New Search

transvestism (cross-dressing) (tranz-vest-izm) n.

dressing in clothes normally associated with the opposite sex, which may occur in both heterosexual and homosexual people. Cross-dressing may be practised by transsexuals (see TRANSSEXUALISM), in whom it is not sexually arousing. In fetishistic transvestites (see FETISHISM) cross-dressing is sexually arousing. See also SEXUAL DEVIATION.
—transvestite n.

Back  -    New Search

tranylcypromine (tran-il-sy-proh-meen) n.

an antidepressant drug – one of the MAO inhibitors - given by mouth for the treatment of severe mental depressive states. Trade name: Parnate .

Back  -    New Search

trapezium (tr-pee-zim) n.

a bone of the wrist (see CARPUS). It articulates with the scaphoid bone behind, with the first metacarpal in front, and with the trapezoid and second metatarsal on either side.

Back  -    New Search

trapezius (tr-pee-zi-s) n.

a flat triangular muscle covering the back of the neck and shoulder. It moves the scapula and draws the head backwards to either side.

Back  -    New Search

trapezoid bone (tr-pee-zoid) n.

a bone of the wrist (see CARPUS). It articulates with the second metatarsal bone in front, with the scaphoid bone behind, and with the trapezium and capitate bones on either side.

Back  -    New Search

trauma (traw-m) n.

1 a physical wound or injury. t. scores numerical systems for assessing the severity and prognosis of serious injuries.

2 (in psychology) an emotionally painful and harmful event, which may lead to neurosis. See POSTTRAUMATIC STRESS DISORDER.
Top

—traumatic (traw-mat-ik) adj.

Back  -    New Search

traumatic fever n.

a fever resulting from a serious injury.

Back  -    New Search

traumatology (traw-m-tol-ji) n.

accident surgery: the branch of surgery that deals with wounds and disabilities arising from injuries.

Back  -    New Search

travel sickness (trav-l) n.

see MOTION SICKNESS.

Back  -    New Search

trazodone (traz-oh-dohn) n.

a drug administered by mouth in the treatment of depression with and without anxiety. Trade name: Molipaxin .

Back  -    New Search

Treacher Collins syndrome (Treacher Collins deformity) (tree-cher kol-inz) n.

a hereditary disorder of facial development. The lower jaw and zygomatic (cheek) bones are underdeveloped and the precursors of the ear fail to develop, which results in a variety of ear and facial malformations. [E. Treacher Collins (1862–1919), British ophthalmologist]

Back  -    New Search

trematode (trem--tohd) n.

see FLUKE.

Back  -    New Search

tremor (trem-er) n.

a rhythmical alternating movement that may affect any part of the body. essential t. a slow tremor that particularly affects the hands. intention t. tremor that occurs when a patient with disease of the cerebellum tries to touch an object. physiological t. a feature of the normal mechanism for maintaining posture. It may be more apparent in states of fatigue or anxiety. resting t. tremor that occurs only when the patient is at rest and disappears when movement is attempted. It is a prominent symptom of parkinsonism.

Back  -    New Search

trench foot (immersion foot) (trench) n.

blackening of the toes and the skin of the foot due to death of the superficial tissues and caused by prolonged immersion in cold water or exposure to damp and cold.

Back  -    New Search

Trendelenburg position (tren-del-n-berg) n.

a special operating-table posture for patients undergoing surgery of the pelvis or for patients suffering from shock. The patient is laid on his back with the pelvis higher than the head, inclined at an angle of about 45°. See POSITION. [F. Trendelenburg (1844–1924), German surgeon]

Back  -    New Search

Trendelenburg's operation n.

ligation of the long saphenous vein at the groin: performed to remove weakened portions of varicose veins.

Back  -    New Search

Trendelenburg's sign n.

a sign indicating congenital dislocation of the hip: when the patient stands on the affected leg with the other leg flexed, the pelvis is lower on the side of the flexed leg.

Back  -    New Search

trephine (trif-een) n.

a surgical instrument used to remove a circular area of tissue, usually from the cornea of the eye or from bone.

Back  -    New Search

Treponema (trep--nee-m) n.

a genus of anaerobic spirochaete bacteria. All species are parasitic; some cause disease, such as T. carateum (pinta), T. pallidum (syphilis), and T. pertenue (yaws).

Back  -    New Search

treponematosis (trep--nee-m-toh-sis) n.

any infection caused by spirochaete bacteria of the genus Treponema.

Back  -    New Search

tretinoin (tre-tin-oh-in) n.

a drug (see RETINOID) used in the treatment of acne. It is administered topically as a cream, gel, or liquid. Trade name: Retin-A .

Back  -    New Search

triad (try-ad) n.

(in medicine) a group of three united or closely associated structures or three symptoms or effects that occur together.

Back  -    New Search

triage (tree-ahzh) n.

a system whereby a group of casualties or other patients is sorted according to the seriousness of their injuries or illnesses so that treatment priorities can be allocated between them. In emergency situations it is designed to maximize the number of survivors.

Back  -    New Search

triamcinolone (try-am-sin--lohn) n.

a synthetic corticosteroid hormone with uses similar to cortisone; it reduces inflammation but does not cause salt and water retention. It is administered by mouth. Trade names: Adcortyl , Ledercort .

Back  -    New Search

triamterene (try-am-ter-een) n.

a potassium-sparing diuretic that causes the loss of sodium and chloride from the kidneys and is administered by mouth in the treatment of various forms of fluid retention (oedema). Trade name: Dytac .

Back  -    New Search

triangle (try-ang-l) n.

(in anatomy) a three-sided structure or area; for example, the femoral triangle.

Back  -    New Search

triangular bandage (try-ang-yoo-ler) n.

a piece of material cut or folded into a triangular shape and used for making an arm sling or holding dressings in position.

Back  -    New Search

triceps (try-seps) n.

a muscle with three heads of origin. t. brachii the muscle that is situated on the back of the upper arm and contracts to extend the forearm. It is the antagonist of the brachialis.

Back  -    New Search

trich- (tricho-) prefix

denoting hair or hairlike structures.

Back  -    New Search

trichiasis (trik-I--sis) n.

a condition in which the eyelashes rub against the eyeball, producing discomfort and sometimes ulceration of the cornea. It accompanies all forms of entropion.

Back  -    New Search

trichinosis (trichiniasis) (trik-i-noh-sis) n.

a disease caused by larvae of the nematode worm Trichinella spiralis, contracted by eating imperfectly cooked infected meat. Symptoms include diarrhoea, nausea, fever, vertigo, delirium, and pains in the limbs. The larvae eventually settle within cysts in the muscles, which may result in pain and stiffness.

Back  -    New Search

trichloracetic acid (try-klor--see-tik) n.

an astringent used in solution for a variety of skin conditions. It is also applied topically to produce sloughing, especially for the removal of warts.

Back  -    New Search

trichobezoar (trik-oh-bee-zor) n.

hairball: a mass of swallowed hair in the stomach. See BEZOAR.

Back  -    New Search

Trichocephalus (trik-oh-sef--ls) n.

see WHIPWORM.

Back  -    New Search

trichology (trik-ol-ji) n.

the study of hair.

Back  -    New Search

Trichomonas (trik-oh-moh-ns) n.

a genus of parasitic flagellate protozoans. T. hominis a species that lives in the large intestine. T. vaginalis see TRICHOMONIASIS.

Back  -    New Search

trichomoniasis (trik-oh-m-ny--sis) n.

1 an infection of the digestive system by the protozoan Trichomonas hominis, causing dysentery.

2 an infection of the vagina due to the protozoan Trichomonas vaginalis, causing inflammation of genital tissues with vaginal discharge. It can be transmitted to males in whom it causes urethral discharge. Treatment with metronidazole is effective.
Top

Back  -    New Search

trichomycosis (trik-oh-my-koh-sis) n.

any hair disease caused by infection with a fungus.

Back  -    New Search

Trichophyton (trik-oh-fy-tn) n.

a genus of fungi, parasitic to man, that frequently infect the skin, nails, and hair and cause tinea (ringworm). See also DERMATOPHYTE.

Back  -    New Search

trichophytosis (trik-oh-fy-toh-sis) n.

a fungal infection caused by species of Trichophyton.

Back  -    New Search

trichromatic (try-kroh-mat-ik) adj.

describing or relating to the normal state of colour vision, in which a person is sensitive to all three of the primary colours. Compare DICHROMATIC.

Back  -    New Search

trichuriasis (trik-yoor-I--sis) n.

an infestation of the large intestine by the whipworm, Trichuris trichiura. Symptoms, including bloody diarrhoea, anaemia, weakness, and abdominal pain, are evident only in heavy infestations. Trichuriasis can be treated with various anthelmintics, including thiabendazole and piperazine salts.

Back  -    New Search

Trichuris (trik-yoor-iss) n.

see WHIPWORM.

Back  -    New Search

tricuspid valve (try-kusp-id) n.

the valve in the heart between the right atrium and right ventricle. It consists of three cusps that channel the flow of blood from the atrium to the ventricle and prevent any backflow.

Back  -    New Search

tricyclic antidepressant (try-sy-klik) n.

see ANTIDEPRESSANT.

Back  -    New Search

tridactyly (try-dak-tili) n.

a congenital abnormality in which there are only three digits on a hand or foot.

Back  -    New Search

trifluoperazine (try-floo-oh-pair--zeen) n.

a phenothiazine antipsychotic drug with uses and effects similar to those of chlorpromazine. Trade name: Stelazine .

Back  -    New Search

trigeminal nerve (try-jem-in-l) n.

the fifth and largest cranial nerve (V), which is split into the ophthalmic, maxillary, and mandibular nerves. The motor fibres are responsible for controlling the muscles involved in chewing, while the sensory fibres relay information from the front of the head and from the meninges.

Back  -    New Search

trigeminal neuralgia (tic douloureux) n.

see NEURALGIA.

Back  -    New Search

trigeminy (try-jem-in-i) n.

a condition in which the heartbeats can be subdivided into groups of three. The first beat is normal, but the second and third are premature beats (see ECTOPIC BEAT).

Back  -    New Search

trigger finger (trig-er) n.

an impairment in the ability to extend a finger, resulting either from a nodular thickening in the flexor tendon or a narrowing of the flexor tendon sheath. On unclenching the fist, the affected finger at first remains bent then suddenly straightens.

Back  -    New Search

triglyceride (try-glis-eryd) n.

a lipid or neutral fat consisting of glycerol combined with three fatty-acid molecules. Triglycerides are the form in which fat is stored in the body.

Back  -    New Search

trigone (try-gohn) n.

a triangular region of tissue, such as the triangular region of the wall of the bladder that lies between the openings of the two ureters and the urethra.

Back  -    New Search

trigonitis (try-goh-ny-tis) n.

inflammation of the trigone (base) of the urinary bladder. This can occur as part of a generalized cystitis or it can be associated with inflammation in the urethra, prostate, or neck (cervix) of the uterus.

Back  -    New Search

trigonocephaly (try-g-noh-sef-li) n.

a deformity of the skull in which the vault of the skull is sharply angled just in front of the ears, giving the skull a triangular shape.
—trigonocephalic (try-g-noh-si-fal-ik) adj.

Back  -    New Search

triiodothyronine (try-I-oh-doh-th'y-r-neen) n.

see THYROID HORMONE.

Back  -    New Search

trimeprazine (try-mep-r-zeen) n.

an antihistamine drug (a phenothiazine derivative) that also possesses sedative properties. Given by mouth, it is mainly used in the treatment of pruritus and urticaria (nettle rash). Trade name: Vallergan .

Back  -    New Search

trimester (try-mest-er) n.

(in obstetrics) any one of the three successive three-month periods into which a pregnancy may be divided.

Back  -    New Search

trimethoprim (try-meth-oh-prim) n.

an antibacterial drug that is active against a range of microorganisms. Administered by mouth or injection, it is used mainly in the treatment of chronic urinary-tract infections and respiratory-tract infections. Trade names: Ipral , Trimopan . See also COTRIMOXAZOLE.

Back  -    New Search

trimipramine (try-mip-r-meen) n.

a tricyclic antidepressant drug that also possesses sedative properties. It is given by mouth or by injection for the treatment of acute or chronic mental depression. Trade name: Surmontil .

Back  -    New Search

trinitrophenol (try-ny-troh-fee-nol) n.

see PICRIC ACID.

Back  -    New Search

triple marker test (trip-l mark-er) n.

a blood test used in the prenatal diagnosis of Down's syndrome, which can be performed at about the 16th week of pregnancy. It measures levels of alpha-fetoprotein (afp), unconjugated oestriol (uE_3), and human chorionic gonadotrophin in maternal serum.

Back  -    New Search

triploid (trip-loid) adj.

describing cells, tissues, or individuals in which there are three complete chromosome sets. Compare HAPLOID, DIPLOID.
—triploid n.

Back  -    New Search

triprolidine (try-proh-li-deen) n.

an anti-histamine drug used to treat allergy and, in combination with other drugs (e.g. dextromethorphan), to relieve the symptoms of colds. Trade name: Actidil .

Back  -    New Search

triquetrum (triquetral bone) (try-kwee-trm) n.

a bone of the wrist (see CARPUS). It articulates with the ulna behind and with the pisiform, hamate, and lunate bones in the carpus.

Back  -    New Search

trismus (triz-ms) n.

spasm of the jaw muscles, keeping the jaws tightly closed. This is the characteristic symptom of tetanus but it also occurs as a sensitivity reaction to certain drugs and in disorders of the basal ganglia.

Back  -    New Search

trisomy (try-soh-mi) n.

a condition in which there is one extra chromosome present in each cell in addition to the normal (diploid) chromosome set; the cause of such disorders as Down's syndrome.
—trisomic (try-soh-mik) adj.

Back  -    New Search

tritanopia (try-t-noh-pi) n.

a rare defect of colour vision in which affected persons are insensitive to blue light and confuse blues and greens. Compare DEUTERANOPIA, DALTONISM.

Back  -    New Search

tritium (trit-im) n.

an isotope of hydrogen that emits beta particles (electrons) during its decay. It has been used as a tracer in the investigation of diseases of the heart and the lungs. Symbol: T or 3H.

Back  -    New Search

trocar (troh-kar) n.

an instrument used in combination with a cannula to draw off fluids from a body cavity. It comprises a metal tube containing a removable shaft with a sharp three-cornered point.

Back  -    New Search

trochanter (troh-kant-er) n.

either of the two protuberances that occur below the neck of the femur.

Back  -    New Search

troche (trohsh) n.

a medicinal lozenge, taken by mouth, used to treat conditions of the mouth, throat, or alimentary canal.

Back  -    New Search

trochlea (trok-li-) n.

an anatomical part having the structure or function of a pulley; for example the fibrocartilaginous ring in the frontal bone through which the tendon of the superior oblique eye muscle passes.
—trochlear (trok-li-er) adj.

Back  -    New Search

trochlear nerve n.

the fourth cranial nerve (IV), which supplies the superior oblique eye muscle.

Back  -    New Search

trochoid joint (pivot joint) (troh-koid) n.

a form of diarthrosis (freely movable joint) in which a bone moves round a central axis, allowing rotational movement.

Back  -    New Search

troph- (tropho-) prefix

denoting nourishment or nutrition.

Back  -    New Search

trophic (trof-ik) adj.

relating to nutrition or to the supply of nutrients, etc., to a part of the body. t. ulcer an ulcer due to insufficient supply of blood or nutrients to the affected part.

Back  -    New Search

trophoblast (trof--blast) n.

the tissue that forms the wall of the blastocyst.

Back  -    New Search

-trophy suffix

denoting nourishment, development, or growth.

Back  -    New Search

-tropicsuffix

denoting 1 turning towards.

2 having an affinity for; influencing.
Top

Back  -    New Search

tropical medicine (trop-ikl) n.

the study of diseases more commonly found in tropical regions than elsewhere, such as malaria, leprosy, trypanosomiasis, schisto-somiasis, and leishmaniasis.

Back  -    New Search

tropical ulcer (Naga sore) n.

a skin disease prevalent in wet tropical regions. A large open sloughing sore usually develops at the site of a wound or abrasion. The ulcer is often infected with spirochaetes and bacteria and may extend deeply and cause destruction of muscles and bones.

Back  -    New Search

tropicamide (tr-pik--myd) n.

a drug used in the form of eye drops to dilate the pupil so that the inside of the eye can more easily be examined or operated upon. Trade name: Mydriacyl .

Back  -    New Search

Trousseau's sign (troo-sohz) n.

spasmodic contractions of muscles, especially the muscles of mastication, in response to nerve stimulation (e.g. by tapping). It is a characteristic sign of hypocalcaemia (see TETANY). [A. Trousseau (1801–67), French physician]

Back  -    New Search

truncus (trunk-s) n.

a trunk: a main vessel or other tubular organ from which subsidiary branches arise. t. arteriosus the main arterial trunk arising from the fetal heart. It develops into the aorta and pulmonary artery.

Back  -    New Search

trunk (trunk) n.

1 see TRUNCUS.

2 the body excluding the head and limbs.
Top

Back  -    New Search

truss (trus) n.

a device for applying pressure to a hernia to prevent it from protruding. It usually consists of a pad attached to a belt worn under the clothing.

Back  -    New Search

trust (trust) n.

(in the NHS) a self-governing body that provides any of a range of health-care services, including hospital services, community health services, and services for the mentally ill and other groups.

Back  -    New Search

trypanocide (trip-an--syd) n.

an agent that kills trypanosomes. The main trypanocides are arsenic-containing compounds.

Back  -    New Search

Trypanosoma (trip--n-soh-m) n.

see TRYPANOSOMIASIS.

Back  -    New Search

trypanosomiasis (trip--n-s-my--sis) n.

any disease caused by the presence of parasitic protozoans of the genus Trypanosoma. The two most important diseases are Chagas' disease (South American t. ), caused by T. cruzi, and sleeping sickness (African t. ), caused by T. rhodesiense or T. gambiense.

Back  -    New Search

tryparsamide (trip-ar-s-myd) n.

a drug used in the treatment of trypanosomiasis (sleeping sickness). Usually given by injection, it penetrates the cerebrospinal fluid and is highly active against the infective organism. Trade name: Tryparsam .

Back  -    New Search

trypsin (trip-sin) n.

an enzyme that continues the digestion of proteins by breaking down peptones into smaller peptide chains (see PEPTIDASE). It is secreted by the pancreas in an inactive form, trypsinogen , which is converted in the duodenum to trypsin by the action of the enzyme enteropeptidase.

Back  -    New Search

trypsinogen (trip-sin--jin) n.

see TRYPSIN.

Back  -    New Search

tryptophan (trip-t-fan) n.

an essential amino acid. See also AMINO ACID.

Back  -    New Search

tsetse (tet-si) n.

a large bloodsucking fly of tropical Africa belonging to the genus Glossina. Tsetse flies transmit the blood parasites that cause sleeping sickness, Trypanosoma gambiense and T. rhodesiense.

Back  -    New Search

TSH n.

see THYROID-STIMULATING HORMONE.

Back  -    New Search

tsutsugamushi disease (tsoo-tsoo-g-moo-shi) n.

see SCRUB TYPHUS.

Back  -    New Search

tubal occlusion (tew-bal) n.

blocking of the Fallopian tubes. This is achieved by surgery as a means of sterilization; it is also a result of pelvic inflammatory disease.

Back  -    New Search

tubal pregnancy (oviducal pregnancy) n.

see ECTOPIC PREGNANCY.

Back  -    New Search

tube (tewb) n.

(in anatomy) a long hollow cylindrical structure, e.g. a Fallopian tube.

Back  -    New Search

tuber (tew-ber) n.

(in anatomy) a thickened or swollen part.

Back  -    New Search

tubercle (tew-ber-kl) n.

1 (in anatomy) a small rounded protuberance on a bone.

2 the specific nodular lesion of tuberculosis.
Top

Back  -    New Search

tubercular (tew-ber-kew-ler) adj.

having small rounded swellings or nodules, not necessarily caused by tuberculosis.

Back  -    New Search

tuberculide (tew-ber-kew-lyd) n.

an eruption of the skin that arises in response to an internal focus of tuberculosis.

Back  -    New Search

tuberculin (tew-ber-kew-lin) n.

a protein extract from cultures of tubercle bacilli, used to test whether a person has suffered from or been in contact with tuberculosis (see MANTOUX TEST).

Back  -    New Search

tuberculoma (tew-ber-kew-loh-m) n.

a mass of cheeselike material resembling a tumour, seen in some cases of tuberculosis. Tuberculomas are found in a variety of sites, including the lung or brain.

Back  -    New Search

tuberculosis (tew-ber-kew-loh-sis) n.

an infectious disease caused by the bacillus Mycobacterium tuberculosis and characterized by the formation of nodular lesions (tubercles) in the tissues. In the most common form of the disease (pulmonary t. ) the bacillus is inhaled into the lungs where it sets up a primary tubercle and spreads to the nearest lymph nodes (the primary complex ). Many people become infected but show no symptoms. Others develop a chronic infection and can transmit the bacillus by coughing and sneezing. Symptoms of the active disease include fever, night sweats, weight loss, and the spitting of blood. In some cases the bacilli spread from the lungs to the bloodstream, setting up millions of tiny tubercles throughout the body (miliary t. ). Bacilli entering by the mouth, usually in infected cows' milk, set up a primary complex in abdominal lymph nodes, leading to peritonitis, and sometimes spread to other organs, joints, and bones (see POTT'S DISEASE).
Tuberculosis is curable by various combinations of the antibiotics streptomycin, ethambutol, isoniazid (INH), rifampicin, and pyrazinamide. Preventive measures in the UK include the detection of cases by X-ray screening of vulnerable populations and inoculation with BCG vaccine.

Back  -    New Search

tuberculous (tew-ber-kew-ls) adj.

relating to or affected with tuberculosis.

Back  -    New Search

tuberose (tew-ber-ohz) adj.

see TUBEROUS.

Back  -    New Search

tuberosity (tew-ber-os-iti) n.

a large rounded protuberance on a bone.

Back  -    New Search

tuberous (tuberose) (tew-ber-s) adj.

knobbed; having nodules or rounded swellings. t. sclerosis (epiloia , Bourneville's disease ) a hereditary disorder in which the brain, eyes, skin, and other organs are studded with small plaques or tumours. Symptoms include epilepsy, mental retardation, and behavioural disorders.

Back  -    New Search

tubo- prefix

denoting a tube, especially a Fallopian tube or the Eustachian tube.

Back  -    New Search

tuboabdominal (tew-boh-ab-dom-inl) adj.

relating to or occurring in a Fallopian tube and the abdomen.

Back  -    New Search

tubocurarine (tew-boh-kewr-ar-een) n.

a drug given by intravenous injection to produce relaxation of voluntary muscles before surgery and in such conditions as tetanus, encephalitis, and poliomyelitis (see MUSCLE RELAXANT). Trade names: Jexin , Tubarine .

Back  -    New Search

tubo-ovarian (tew-boh-oh-vair-in) adj.

relating to or occurring in a Fallopian tube and an ovary.

Back  -    New Search

tubotympanal (tew-boh-timp-n-l) adj.

relating to the tympanic cavity and the Eustachian tube.

Back  -    New Search

tubule (tew-bewl) n.

(in anatomy) a small cylindrical hollow structure. See also RENAL (TUBULE), SEMINIFEROUS TUBULE.

Back  -    New Search

tularaemia (rabbit fever)(tew-l-ree-mi) n.

a disease of rodents and rabbits, caused by the bacterium Francisella tularensis, that may be transmitted to man. Symptoms include an ulcer at the site of infection, inflamed and ulcerating lymph nodes, headache, aching pains, loss of weight, and a fever lasting several weeks. Treatment with chloramphenicol, streptomycin, or tetracycline is effective.

Back  -    New Search

tulle gras (tewl grah) n.

a soft dressing consisting of open-woven silk (or other material) impregnated with a waterproof soft paraffin wax.

Back  -    New Search

tumefaction (tew-mi-fak-shn) n.

the process in which a tissue becomes swollen and tense by accumulation within it of fluid under pressure.

Back  -    New Search

tumescence (tew-mes-ns) n.

a swelling, or the process of becoming swollen, usually because of an accumulation of blood or other fluid within the tissues.

Back  -    New Search

tumid (tew-mid) adj.

swollen.

Back  -    New Search

tumor (tew-mer) n.

swelling: one of the four classical signs of inflammation in a tissue. See also CALOR, DOLOR, RUBOR.

Back  -    New Search

tumour (tew-mer) n.

any abnormal swelling in or on a part of the body. The term is usually applied to an abnormal growth of tissue, which may be benign or malignant. Compare CYST.

Back  -    New Search

tunica (tew-nik-) n.

a covering or layer of an organ or part; for example, a layer of the wall of a blood vessel (see ADVENTITIA, INTIMA, MEDIA).

Back  -    New Search

tunnel (tun-l) n.

(in anatomy) a canal or hollow groove.

Back  -    New Search

TUR (TURP) n.

transurethral resection of the prostate: see RESECTION.

Back  -    New Search

turbinate bone (ter-bin-ayt) n.

see NASAL (CONCHA).

Back  -    New Search

turbinectomy (ter-bin-ek-tmi) n.

the surgical removal of one of the turbinate bones.

Back  -    New Search

turgescence (ter-jes-ns) n.

a swelling, or the process by which a swelling arises in tissues, usually by the accumulation of blood or other fluid under pressure.

Back  -    New Search

turgid (ter-jid) adj.

swollen and congested, especially with blood.

Back  -    New Search

turgor (ter-ger) n.

a state of being swollen or distended.

Back  -    New Search

Turner's syndrome (ter-nerz) n.

a genetic defect in women in which there is only one X chromosome instead of the usual two. Affected women are infertile: they have female external genitalia but no ovaries. Characteristically they are short and have variable developmental defects. [H. H. Turner (1892–1970), US endocrinologist]

Back  -    New Search

turricephaly (tu-ri-sef-li) n.

see OXYCEPHALY.

Back  -    New Search

tussis (tus-iss)

see COUGHING.

Back  -    New Search

twilight state (twy-lyt) n.

a condition of disturbed consciousness in which the individual can still carry out some normal activities but is impaired in his awareness and has no memory of what he has done. It is encountered after epileptic attacks, in alcoholism, and in organic states of confusion.

Back  -    New Search

twins (twinz) pl. n.

two individuals who are born at the same time and of the same parents. fraternal (or dizygotic ) t. twins resulting from the simultaneous fertilization of two egg cells; they may be of different sexes and are no more alike than ordinary siblings. identical (or monozygotic ) t. twins resulting from the fertilization of a single egg cell that subsequently divides to give two separate fetuses. They are of the same sex and otherwise genetically identical. See also SIAMESE TWINS.

Back  -    New Search

tylosis (ty-loh-sis) n.

diffuse keratosis occurring especially on the palms and soles. It occurs early in life and is inherited as an autosomal dominant.

Back  -    New Search

tympan- (tympano-) prefix

denoting 1 the eardrum.

2 the middle ear.
Top

Back  -    New Search

tympanic cavity (tim-pan-ik) n.

see MIDDLE EAR.

Back  -    New Search

tympanic membrane (eardrum) n.

the membrane at the inner end of the external auditory meatus, separating the outer and middle ears. When sound waves reach the ear the tympanum vibrates, transmitting these vibrations to the malleus.

Back  -    New Search

tympanites (meteorism) (timp--ny-teez) n.

distension of the abdomen with air or gas: the abdomen is resonant on percussion. Causes include intestinal obstruction, irritable bowel syndrome, and aerophagy.

Back  -    New Search

tympanoplasty (timp--noh-plasti) n.

surgical repair of defects of the eardrum and middle ear ossicles. See MYRINGOPLASTY.

Back  -    New Search

tympanotomy (timp--not-mi) n.

a surgical operation to expose the middle ear and allow access to the ossicles.

Back  -    New Search

tympanum (timp--nm) n.

the middle ear (tympanic cavity) and/or the eardrum (tympanic membrane).

Back  -    New Search

typhlitis (tif-ly-tis) n.

Obsolete. inflammation of the caecum.

Back  -    New Search

typho- prefix

denoting 1 typhoid fever.

2 typhus.
Top

Back  -    New Search

typhoid fever (ty-foid) n.

an infection of the digestive system by the bacterium Salmonella typhi, causing general weakness, high fever, a rash of red spots on the chest and abdomen, chills, sweating, and in serious cases inflammation of the spleen and bones, delirium, and erosion of the intestinal wall leading to haemorrhage. It is transmitted through contaminated food or drinking water. Treatment with such antibiotics as ampicillin, amoxicillin, ciprofloxacin, or chloramphenicol reduces the severity of symptoms. Vaccination with TAB provides temporary immunity. Compare PARATYPHOID FEVER.

Back  -    New Search

typhus (spotted fever) (ty-fs) n.

any one of a group of infections caused by rickettsiae and characterized by severe headache, a widespread rash, prolonged high fever, and delirium. They all respond to treatment with chloramphenicol or tetracyclines. The rickettsiae may be transmitted by lice (epidemic , classical , or louse-borne t. ); rat fleas (endemic , murine , or flea-borne t. ); ticks (see ROCKY MOUNTAIN SPOTTED FEVER); or mites (see RICKETTSIAL POX, SCRUB TYPHUS).

Back  -    New Search

tyramine (ty-r-meen) n.

an amine naturally occurring in cheese. It has a similar effect in the body to that of adrenaline. This effect can be dangerous in patients taking MAO inhibitors (antidepressants), in whom blood pressure may become very high.

Back  -    New Search

tyrosine (ty-roh-seen) n.

see AMINO ACID.

Back  -    New Search

tyrosinosis (ty-roh-si-noh-sis) n.

an inborn defect of metabolism of the amino acid tyrosine causing excess excretion of parahydroxyphenylpyruvic acid in the urine.

Back  -    New Search

tyrothricin (ty-roh-thry-sin) n.

an antibiotic derived from the bacterium Bacillus brevis. It is used in the form of skin applications and lozenges in the treatment of infections of the mouth, throat, and skin and of wounds and burns.

Back  -    New Search

U

UKCC n.

United Kingdom Central Council for Nursing, Midwifery, and Health Visiting: a statutory body, established by the Nurses, Midwives and Health Visitors Act (1979), that regulates the nursing, midwifery, and health visiting professions in the public interest. The UKCC took over the roles of the General Nursing Councils in England and Wales, Scotland, and Northern Ireland.

Back  -    New Search

ulcer (ul-ser) n.

a break in the skin or in the mucous membrane lining the alimentary tract that fails to heal and is often accompanied by inflammation. decubitus u. see BEDSORE. rodent u. see BASAL CELL CARCINOMA. venous (or hypostatic or varicose ) u. the most common type of skin ulcer, occurring on the legs and caused by increased venous pressure. It most commonly affects older women. See also APHTHA, DENDRITIC ULCER, DUODENAL ULCER, GASTRIC (ULCER), PEPTIC (ULCER).

Back  -    New Search

ulcerative colitis (ul-ser-ay-tiv) n.

see COLITIS.

Back  -    New Search

ulcerative gingivitis (Vincent's angina) n.

acute painful inflammation and ulceration of the gums associated with infection by the microorganisms Fusobacterium and Bacteroides.

Back  -    New Search

ule- (ulo-) prefix

denoting 1 scars; scar tissue.

2 the gums.
Top

Back  -    New Search

ulna (ul-n) n.

the inner and longer bone of the forearm. It articulates with the humerus and radius above and with the radius and indirectly with the wrist bones below.
—ulnar (ul-ner) adj.

Back  -    New Search

ulnar artery n.

a branch of the brachial artery arising at the elbow and running deep within the muscles of the medial side of the forearm to the palm of the hand.

Back  -    New Search

ulnar nerve n.

one of the major nerves of the arm. It originates in the neck and runs down the inner side of the upper arm to behind the elbow. It supplies the muscles of the forearm and the skin of the palm and fourth and fifth fingers.

Back  -    New Search

ultra- prefix

denoting 1 beyond.

2 an extreme degree (e.g. of large or small size).
Top

Back  -    New Search

ultrafiltration (ultr-fil-tray-shn) n.

filtration under pressure. In the kidney, blood is subjected to ultrafiltration to remove the waste material that goes to make up urine.

Back  -    New Search

ultramicroscopic (ultr-my-kr-skop-ik) adj.

too small to be seen by means of an ordinary light microscope.

Back  -    New Search

ultrasonics (ultr-sonn-iks) n.

the study of the uses and properties of ultrasound.
—ultrasonic adj.

Back  -    New Search

ultrasonography (sonography) (ultr-sonn-og-rfi) n.

the use of ultrasound, usually in excess of 1 MHz, to produce images of structures of the human body that may be observed on a TV screen and subsequently transferred to photographic film. It is based on the principle of detecting the reflected waves (echoes) occurring at interfaces within human organs, following a short pulse of ultrasound. This is repeated many times to build up a complete picture. Both the transmitter and detector are contained within the scanning probe (see TRANSDUCER). As far as is known, there are no adverse effects from the use of ultrasound and it has particular value in obstetrics and in examination of the biliary and urinary tract and the vascular tree. intraoperative u. a specialized technique of ultrasonography performed endoscopically during an operation. transvaginal u. ultrasonography using a vaginal probe. It provides superior resolution and therefore a detailed anatomy of the female pelvis and early and accurate identification of fetal structures. See also ECHOCARDIOGRAPHY.

Back  -    New Search

ultrasound (ultrasonic waves) (ul-tr-sownd) n.

sound waves of extremely high frequency (above 20,000 Hz), inaudible to the human ear. Ultrasound, usually in excess of 1 MHz, can be used to examine the structure of the inside of the body (see ULTRASONOGRAPHY); the vibratory effect of ultrasound can also be used to break up stones (see LITHOTRIPSY) and cataracts (see PHACOEMULSIFICATION) and in the treatment of rheumatic conditions.

Back  -    New Search

ultrasound marker (mark-er) n.

the appearance, on ultrasound examination, of a particular physical abnormality in the fetus at a specific stage in fetal development. Such markers suggest the presence of specific chromosomal or developmental abnormalities. See also NUCHAL (THICKNESS SCANNING).

Back  -    New Search

ultraviolet rays (ultr-vy--lit) pl. n.

invisible short-wavelength radiation beyond the violet end of the visible spectrum. Sunlight contains ultraviolet rays, which are responsible for the production of both suntan and – on overexposure – sunburn.

Back  -    New Search

umbilical cord (um-bil-ikl) n.

the strand of tissue connecting the fetus to the placenta. It contains two arteries that carry blood to the placenta and one vein that returns it to the fetus.

Back  -    New Search

umbilicated (um-bil-i-kayt-id) adj.

having a navel-like depression.

Back  -    New Search

umbilicus (omphalus) (um-bil-iks) n.

the navel: a circular depression in the centre of the abdomen marking the site of attachment of the umbilical cord in the fetus.
—umbilical adj.

Back  -    New Search

umbo (um-boh) n.

a projecting centre of a round surface, especially the projection of the inner surface of the eardrum to which the malleus is attached.

Back  -    New Search

unciform bone (un-si-form) n.

see HAMATE BONE.

Back  -    New Search

uncinate fits (un-sin-ayt) pl. n.

a form of temporal lobe epilepsy in which hallucinations of taste and smell and inappropriate chewing movements are prominent features.

Back  -    New Search

unconscious (un-kon-shs) adj.

1 in a state of unconsciousness
.
2 (in psychoanalysis) denoting the part of the mind that includes memories, motives, and intentions that are not accessible to awareness and cannot be made conscious without overcoming resistances. Compare SUBCONSCIOUS.
Top

Back  -    New Search

unconsciousness (un-kon-shs-nis) n.

a condition of being unaware of one's surroundings, as in sleep, or of being unresponsive to stimulation. An unnatural state of unconsciousness may be caused by factors that produce reduced brain activity, such as lack of oxygen or head injuries, or it may be brought about deliberately during general anaesthesia. See also COMA.

Back  -    New Search

uncus (unk-s) n.

any hook-shaped structure, especially a projection of the lower surface of the cerebral hemisphere.

Back  -    New Search

undecenoic acid (un-des-i-noh-ik) n.

an antifungal agent, applied to the skin in the form of powder, ointment, lotion, or aerosol spray for the treatment of such infections as athlete's foot. Trade name: Mycota .

Back  -    New Search

undine (un-deen) n.

a small rounded container, usually made of glass, for solutions used to wash out the eye. It has a small neck for filling and a long tapering spout with a narrow outlet.

Back  -    New Search

undulant fever (un-dew-lnt) n.

see BRUCELLOSIS.

Back  -    New Search

ungual (ung-wl) adj.

relating to the fingernails or toenails (ungues).

Back  -    New Search

unguentum (ung-wen-tm) n.

(in pharmacy) an ointment.

Back  -    New Search

unguis (ung-wis) n.

a fingernail or toenail. See NAIL.

Back  -    New Search

uni- prefix

denoting one.

Back  -    New Search

unicellular (yoo-ni-sel-yoo-ler) adj.

describing organisms or tissues that consist of a single cell.

Back  -    New Search

unilateral (yoo-ni-lat-erl) adj.

(in anatomy) relating to or affecting one side of the body or one side of an organ or other part.

Back  -    New Search

union (yoon-yn) n.

(in a fractured bone) the successful result of healing of a fracture, in which the bone ends have become firmly united by newly formed bone. Compare MALUNION.

Back  -    New Search

uniovular (yoo-ni-ov-yoo-ler) adj.

derived from a single ovum, as are identical twins. Compare BINOVULAR.

Back  -    New Search

unipolar (yoo-ni-poh-ler) adj.

(in neurology) describing a neurone that has one main process extending from the cell body. Compare BIPOLAR.

Back  -    New Search

United Kingdom Central Council for Nursing, Midwifery, and Health Visiting (yoo-ny-tid) n.

see UKCC.

Back  -    New Search

Unna's paste (oo-nz) n.

a dressing for varicose ulcers consisting of a mixture of zinc oxide, gelatin, and glycerine, applied between layers of a spiral bandage. [P. G. Unna (1850–1929), German dermatologist]

Back  -    New Search

UPPP n.

see UVULOPALATOPHARYNGOPLASTY.

Back  -    New Search

urachus (yoor--ks) n.

the remains of the cavity of the allantois. It usually disappears during embryonic development, leaving a solid fibrous cord connecting the bladder with the umbilicus.
—urachal adj.

Back  -    New Search

uracil (yoor--sil) n.

one of the nitrogen-containing bases (see PYRIMIDINE) occurring in the nucleic acid RNA.

Back  -    New Search

uraemia (yoor-ee-mi) n.

the presence of excessive amounts of urea and other nitrogenous waste compounds in the blood. This occurs in kidney failure and results in nausea, vomiting, lethargy, drowsiness, and eventually (if untreated) death. Treatment may require haemodialysis on a kidney machine.
—uraemic adj.

Back  -    New Search

uramustine (yoor--must-een) n.

a cytotoxic drug administered by intravenous injection in the treatment of various forms of cancer, particularly chronic lymphatic leukaemia.

Back  -    New Search

uran- (urano-) prefix

denoting the palate.

Back  -    New Search

urataemia (yoor--tee-mi) n.

the presence in the blood of sodium urate and other urates, formed by the reaction of uric acid with bases. See also GOUT.

Back  -    New Search

urate (yoor-ayt) n.

a salt of uric acid, normally present in the urine. Excess amounts occur in the blood and joints in gout.

Back  -    New Search

uraturia (yoor-t-yoor-i) n.

the presence in the urine of urates. Abnormally high concentrations of urates in urine occur in gout.

Back  -    New Search

urea (yoor-ee-) n.

the main breakdown product of protein metabolism. It is the chemical form in which unrequired nitrogen is excreted by the body in the urine. Urea is formed in the liver from ammonia and carbon dioxide.

Back  -    New Search

urease (yoor-i-ayz) n.

an enzyme that catalyses the hydrolysis of urea to ammonia and carbon dioxide.

Back  -    New Search

urecchysis (yoor-ek-i-sis) n.

the escape of uric acid from the blood into spaces in the connective tissue.

Back  -    New Search

uresis (yoor-ee-sis) n.

see URINATION.

Back  -    New Search

ureter (yoor-ee-ter) n.

either of a pair of tubes, 25–30 cm long, that conduct urine from the pelvis of kidneys to the bladder.
—ureteral, ureteric (yoor-i-te-rik) adj.

Back  -    New Search

ureter- (uretero-) prefix

denoting the ureter(s).

Back  -    New Search

ureterectomy (yoor-i-ter-ek-tmi) n.

surgical removal of a ureter. This usually includes removal of the associated kidney as well (see NEPHROURETERECTOMY).

Back  -    New Search

ureteritis (yoor-i-ter-l-tis) n.

inflammation of the ureter. This usually occurs in association with cystitis, particularly if caused by vesicoureteric reflux.

Back  -    New Search

ureterocele (yoor-ee-ter-oh-seel) n.

a cystic swelling of the wall of the ureter at the point where it passes into the bladder. It is associated with stenosis of the opening of the ureter and it may cause impaired drainage of the kidney with dilatation of the ureter and hydronephrosis.

Back  -    New Search

ureteroenterostomy (yoor-ee-ter-oh-en-ter-ost-mi) n.

an artificial communication that is surgically created between the ureter and the bowel. See also URETEROSIGMOIDOSTOMY.

Back  -    New Search

ureterolith (yoor-ee-ter-oh-lith) n.

a stone in the ureter. See CALCULUS, URETERO-LITHOTOMY.

Back  -    New Search

ureterolithotomy (yoor-ee-ter-oh-lith-ot-mi) n.

the surgical removal of a stone (calculus) from the ureter. If the stone occupies the lower portion of the ureter, it may be extracted by cystoscopy, thus avoiding open surgery.

Back  -    New Search

ureterolysis (yoor-i-ter-ol-i-sis) n.

an operation to free one or both ureters from surrounding fibrous tissue causing an obstruction.

Back  -    New Search

ureteroneocystostomy (yoor-ee-ter-oh-nee-oh-sist-ost-mi) n.

the surgical reimplantation of a ureter into the bladder. This is most commonly performed to cure vesicoureteric reflux.

Back  -    New Search

ureteronephrectomy (yoor-ee-ter-oh-ni-frek-tmi) n.

see NEPHROURETERECTOMY.

Back  -    New Search

ureteroplasty (yoor-ee-ter-oh-plasti) n.

surgical reconstruction of the ureter using a segment of bowel or a tube of bladder.

Back  -    New Search

ureteropyelonephritis (yoor-ee-ter-oh-py--loh-ni-fry-tis) n.

inflammation involving both the ureter and the renal pelvis (see URETERITIS, PYELITIS).

Back  -    New Search

ureteroscope (yoor-ee-ter--skohp) n.

a rigid or flexible instrument that can be passed into the ureter and up into the pelvis of the kidney. Usually, the ureter needs to be dilated before the instrument is passed. It is most commonly used to visualize a stone in the ureter and remove it safely under direct vision with a stone basket or forceps. Larger stones can be fragmented with an ultrasound or electro-hydraulic lithotripsy probe, passed through the instrument.

Back  -    New Search

ureteroscopy (yoor-i-ter-s-k-pi) n.

inspection of the lumen of the ureter with a ureteroscope.

Back  -    New Search

ureterosigmoidostomy (yoor-ee-ter-oh-sig-moid-ost-mi) n.

the operation of implanting the ureters into the sigmoid colon. This method of permanent urinary diversion may be used after cystectomy or to bypass a diseased or damaged bladder. The urine is passed together with the faeces, avoiding the need for an external opening and appliance to collect the urine.

Back  -    New Search

ureterostomy (yoor-i-ter-ost-mi) n.

the surgical creation of an external opening into the ureter. This usually involves bringing the ureter to the skin surface so that the urine can drain into a suitable appliance (cutaneous u. ).

Back  -    New Search

ureterotomy (yoor-i-ter-ot-mi) n.

surgical incision into the ureter, most commonly performed in ureterolithotomy.

Back  -    New Search

ureterovaginal (yoor-ee-ter-oh-v-jy-nl) adj.

relating to or between the ureter and vagina.

Back  -    New Search

urethane (yoor-i-thayn) n.

a drug administered by mouth to treat some forms of cancer.

Back  -    New Search

urethr- (urethro-) prefix

denoting the urethra.

Back  -    New Search

urethra (yoor-ee-thr) n.

the tube that conducts urine from the bladder to the exterior. The female urethra is quite short (about 3.5 cm) and opens just within the vulva, between the clitoris and vagina. The male urethra is longer (about 20 cm) and runs through the penis. It also serves as the ejaculatory duct.
—urethral adj.

Back  -    New Search

urethritis (yoor-i-thry-tis) n.

inflammation of the urethra, due either to infection or to the presence of a catheter in the urethra. The symptoms are those of urethral discharge with painful or difficult urination (dysuria). nongonococcal (or nonspecific ) u. (NGU, NSU) urethritis due to a sexually transmitted infection other than gonorrhoea, often infection with Chlamydia trachomatis. specific u. urethritis due to gonorrhoea.

Back  -    New Search

urethrocele (yoor-ee-throh-seel) n.

prolapse of the urethra into the vaginal wall causing a bulbous swelling to appear in the vagina, particularly on straining. The condition is associated with previous childbirth. Treatment usually involves surgical repair of the lax tissues.

Back  -    New Search

urethrography (yoor-i-throg-rfi) n.

X-ray examination of the urethra, after introduction of a radiopaque fluid, so that its outline and any narrowing or other abnormalities may be observed in X-ray photographs (urethrograms ).

Back  -    New Search

urethroplasty (yoor-ee-throh-plasti) n.

surgical repair of the urethra, especially a urethral stricture. The operation entails the insertion of a flap or patch of skin from the scrotum or perineum into the urethra at the site of the stricture, which is laid widely open. transpubic u. surgical repair of a ruptured posterior urethra following a fractured pelvis. Access to the damaged urethra is achieved by partial removal of the public bone.

Back  -    New Search

urethrorrhaphy (yoor-i-thro-rfi) n.

surgical restoration of the continuity of the urethra. This may be required following laceration of the urethra.

Back  -    New Search

urethrorrhoea (yoor-ee-thr-ree-) n.

a discharge from the urethra. This is a symptom of urethritis.

Back  -    New Search

urethroscope (yoor-ee-thr-skohp) n.

an endoscope, consisting of a fine tube fitted with a light and lenses, for examination of the interior of the male urethra.
—urethroscopy (yoor-i-throsk-pi) n.

Back  -    New Search

urethrostenosis (yoor-ee-throh-sti-noh-sis) n.

a stricture of the urethra.

Back  -    New Search

urethrostomy (yoor-i-throst-mi) n.

the operation of creating an opening of the urethra in the perineum in men. This can be permanent, to bypass a severe stricture of the urethra in the penis, or it can form the first stage of a urethroplasty.

Back  -    New Search

urethrotomy (yoor-i-throt-mi) n.

the operation of cutting a stricture in the urethra. It is usually performed with a urethrotome : a type of endoscope that consists of a sheath down which is passed a fine knife.

Back  -    New Search

-uria suffix

denoting 1 a condition of urine or urination.

2 the presence of a specified substance in the urine.
Top

Back  -    New Search

uric acid (yoor-ik) n.

a nitrogenous organic acid that is the end-product of nucleic acid metabolism and is a component of the urine. Crystals of uric acid are deposited in the joints of people suffering from gout.

Back  -    New Search

uricosuric drug (yoor-i-koh-sewr-ik) n.

a drug, such as probenecid or sulphinpyrazone, that increases the amount of uric acid excreted in the urine. Uricosuric drugs are used to treat gout and other conditions in which the levels of uric acid in the blood are increased.

Back  -    New Search

uridrosis (yoor-i-droh-sis) n.

the presence of excessive amounts of urea in the sweat; when the sweat dries, a white flaky deposit of urea may remain on the skin. The phenomenon occurs in uraemia.

Back  -    New Search

urin- (urino-, uro-) prefix

denoting urine or the urinary system.

Back  -    New Search

urinalysis (yoor-in-al-i-sis) n.

the analysis of urine, using physical, chemical and microscopical tests, to determine the proportions of its normal constituents and to detect alcohol, drugs, sugar, or other abnormal constituents.

Back  -    New Search

urinary bladder (yoor-in-er-i) n.

see BLADDER.

Back  -    New Search

urinary diversion (dy-ver-shn) n.

any of various techniques for the collection and diversion of urine away from its usual excretory channels, after the bladder has been removed (see CYSTECTOMY) or bypassed. These techniques include ureterosigmoid-ostomy and the construction of an ileal conduit. See also CONTINENT DIVERSION.

Back  -    New Search

urinary tract n.

the entire system of ducts and channels that conduct urine from the kidneys to the exterior. It includes the ureters, the bladder, and the urethra.

Back  -    New Search

urination (micturition) (yoor-in-ay-shn) n.

the periodic discharge of urine from the bladder through the urethra.

Back  -    New Search

urine (yoor-in) n.

the fluid excreted by the kidneys, which contains many of the body's waste products. It is the major route by which the end-products of nitrogen metabolism – urea, uric acid, and creatinine – are excreted. The other major constituent is sodium chloride. Biochemical analysis of urine is commonly used in the diagnosis of diseases; immunological analysis of urine is the basis of most pregnancy tests.

Back  -    New Search

Urine, Normal Biochemical Values for

Determination

Normal range

calcium

2.5–7.5mmol/24h

copper

0.2–1.0µmol/24h

iron

< 1.0mg/24h

lead

< 0.39µmol/24h

magnesium

3.3–4.9mmol/24h

phosphate (inorganic)

15–50mmol/24h

potassium

40–120mmol/24h

sodium

100–250mmol/24h

creatinine

9–17mmol/24h

amylase

8000–30 000 Wohlegmuth U/24h

35–260somogyi units/dl

ascorbic acid

34–68µmol/l

glucose

0.06–0.84mmol/l

hydroxyindole acetic acid (5 HIAA)

16–73µmol/24h

oxalate

< 450µmol/24h

urate

2–6mmol/24h

urea

250–500mmol/24h

urobilinogen

up to 6.7µmol/24h

zinc

2.1–11.0µmol/24h

-amino laevulinic acid

up to 15.3µmol/24h

coproporphyrin

0.09–0.43µmol/24h

porphobilinogen

0.9–8.8µmol/24h

uroporphyrin

5–30µg/24h

ß_2-microglobulin

4–370µg/l

30–370µg/24h

osmolality

350–1000mosm/kg

cortisol

< 280nmol/24h

hydroxymethylmandelic acid

16–48µmol/24h

24-hour urinary excretion

protein

up to 150mg

pregnancy

up to 300mg

albumin

up to 25mg

creatinine

male

9.0–17.0mmol

female

7.5–12.5mmol

pregnancy

8.0–13.5mmol

uric acid

up to 5.0mmol

pregnancy (except late)

up to 7.0mmol

cystine

0.04–0.42mmol

Back  -    New Search

uriniferous tubule (yoor-in-if-er-s) n.

see RENAL (TUBULE).

Back  -    New Search

urinogenital (urogenital) (yoor-in-oh-jen-it'l) adj.

of or relating to the organs and tissues concerned with excretion and reproduction.

Back  -    New Search

urinometer (yoor-in-om-it-er) n.

a hydrometer for measuring the specific gravity of urine.

Back  -    New Search

urobilin (yoor-oh-by-lin) n.

see UROBILINOGEN.

Back  -    New Search

urobilinogen (yoor-oh-by-lin--jin) n.

a colourless product of the reduction of the bile pigment bilirubin. Urobilinogen is formed from bilirubin in the intestine by bacterial action. Part of it is reabsorbed and returned to the liver; part of it is excreted. When exposed to air, urobilinogen is oxidized to a brown pigment, urobilin .

Back  -    New Search

urocele (yoor-oh-seel) n.

a cystic swelling in the scrotum, containing urine that has escaped from the urethra. This may arise following urethral injury.

Back  -    New Search

urochesia (yoor-oh-kee-zi) n.

the passage of urine through the rectum. This may follow a penetrating injury involving both the lower urinary tract and the bowel.

Back  -    New Search

urochrome (yoor-oh-krohm) n.

the pigment responsible for the colour of urine.

Back  -    New Search

urodynamics (yoor-oh-dy-nam-iks) n.

the recording of pressures within the bladder by the use of special equipment that can also record urethral sphincter pressures. It is an essential investigation in the study of urinary incontinence.

Back  -    New Search

urogenital (yoor-oh-jen-it'l) adj.

see URINOGENITAL.

Back  -    New Search

urogram (yoor-oh-gram) n.

an X-ray of the urinary tract or any part of it. It is usually obtained after the intravenous injection of a radiopaque substance, as in an intravenous pyelogram (or urogram), but the contrast medium can also be introduced percutaneously or, in the case of the bladder, transurethrally (for a cystogram ; see CYSTOGRAPHY).

Back  -    New Search

urography (yoor-og-rfi) n.

X-ray examination of any part of the urinary tract after the introduction of a contrast medium. See CYSTOGRAPHY, PYELOGRAPHY, URETHROGRAPHY.

Back  -    New Search

urokinase (yoor-oh-ky-nayz) n.

an enzyme, produced by the kidney, that activates the system involved in dissolving blood clots. It has been used for treating pulmonary embolism. Trade name: Ukidan .

Back  -    New Search

urolith (yoor-oh-lith) n.

a stone in the urinary tract. See CALCULUS.

Back  -    New Search

urology (yoor-ol-ji) n.

the branch of medicine concerned with the study and treatment of diseases of the urinary tract.
—urological (yoor--loj-ikl) adj. —urologist n.

Back  -    New Search

ursodeoxycholic acid (er-soh-dee-oks-i-koh-lik) n.

a drug used to dissolve cholesterol gallstones; it is administered by mouth. Trade names: Destolit , Ursofalk .

Back  -    New Search

urticaria (nettle rash, hives) (er-ti-kair-i) n.

an itchy rash resulting from the release of histamine by mast cells. Individual swellings (weals) appear rapidly and resolve spontaneously within hours. Angio-oedema occurs when the weals involve the lips, eyes, or tongue, which may swell alarmingly and constitute a medical emergency. acute u. a common and immediate response to such allergens as seafood or strawberries. chronic u. a condition that is not allergic and may persist for years.

Back  -    New Search

uter- (utero-) prefix

denoting the uterus.

Back  -    New Search

uterine (yoo-teryn) adj.

of or relating to the uterus.

Back  -    New Search

uterography (yoo-ter-og-rfi) n.

radiography of the uterus.

Back  -    New Search

uterosalpingography (hysterosalpingography) (yoo-ter-oh-sal-ping-og-rfi) n.

radiography of the interior of the uterus and the Fallopian tubes following injection of a radiopaque fluid.

Back  -    New Search

uterovesical (yoo-ter-oh-ves-ikl) adj.

relating to the uterus and bladder.

Back  -    New Search

uterus (womb) (yoo-ter-s) n.

the part of the female reproductive tract that is specialized to allow the embryo to become implanted in its inner wall and to nourish the growing fetus from the maternal blood. The nonpregnant uterus is a pear-shaped organ, about 7.5 cm long, suspended in the pelvic cavity. The upper part is connected to the two Fallopian tubes and the lower part joins the vagina at the cervix. u. didelphys double uterus: a congenital condition resulting from incomplete midline fusion of the two paramesonephric (Müllerian) ducts during early embryonic development. The usual result is a double uterus with one or two cervices and a single vagina. Complete failure of fusion results in a double uterus with double cervices and two separate vaginae.

Back  -    New Search

utilitarianism (yoo-til-i-tair-in-izm) n.

an ethical theory that bases moral judgements or policies on their usefulness or practical value in adding to the sum total of human happiness.

Back  -    New Search

utricle (utriculus) (yoo-trik-l) n.

1 the larger of the two membranous sacs within the vestibule of the ear. It contains a macula, which responds to gravity and relays information to the brain about the position of the head
.
2 a small sac (the prostatic u. ) extending out of the urethra of the male into the substance of the prostate gland.
Top

Back  -    New Search

uvea (uveal tract) (yoo-vi-) n.

the vascular pigmented layer of the eye, which lies beneath the outer layer (sclera). It consists of the choroid, ciliary body, and iris.
—uveal adj.

Back  -    New Search

uveitis (yoo-vi-l-tis) n.

inflammation of any part of the uveal tract of the eye, either the iris (iritis ), ciliary body (cyclitis ), or choroid (choroiditis ). All types may lead to visual impairment, and uveitis is an important cause of blindness.

Back  -    New Search

uveoparotitis (uveoparotid fever) (yoo-vi-oh-pa-r-ty-tis) n.

inflammation of the uvea and swelling of the parotid salivary gland: one of the manifestations of the chronic disease sarcoidosis.

Back  -    New Search

uvula (yoov-yoo-l) n.

a small soft extension of the soft palate that hangs from the roof of the mouth above the root of the tongue. It is composed of muscle, connective tissue, and mucous membrane.

Back  -    New Search

uvulectomy (yoov-yoo-lek-tmi) n.

surgical removal of the uvula.

Back  -    New Search

uvulitis (yoov-yoo-ly-tis) n.

inflammation of the uvula.

Back  -    New Search

uvulopalatopharyngoplasty (UPPP) (yoov-yoo-loh-pal--toh-f-ring-oh-plasti) n.

a surgical operation to remove the uvula, part of the soft palate, and the tonsils in the treatment of snoring.

Back  -    New Search

V

vaccination (vak-si-nay-shn) n.

a means of producing immunity to a disease by using a vaccine. The name was applied originally only to treatment with vaccinia (cowpox) virus, which gives protection against cowpox and smallpox. However, it is now used synonymously with inoculation as a method of immunization against any disease. A vaccine is usually given by injection but may be introduced into the skin through light scratches; for some diseases, oral vaccines are available.

Back  -    New Search

vaccine (vak-seen) n.

a special preparation of antigenic material that can be used to stimulate the development of antibodies and thus confer active immunity against a specific disease or number of diseases. Many vaccines are produced by culturing bacteria or viruses under conditions that lead to a loss of their virulence but not of their antigenic nature. Other vaccines consist of specially treated toxins (toxoids) or of dead bacteria that are still antigenic. See IMMUNIZATION.

Back  -    New Search

vaccinia (vak-sin-i) n.

see COWPOX.

Back  -    New Search

vaccinotherapy (vak-sin-oh-th'e-r-pi) n.

the treatment of disease by the use of vaccines.

Back  -    New Search

vacuole (vak-yoo-ohl) n.

a space within the cytoplasm of a cell, formed by infolding of the cell membrane, that contains material taken in by the cell.

Back  -    New Search

vacuum extractor (ventouse) (vak-yoo-um) n.

a device to assist delivery consisting of a suction cup that is attached to the head of the fetus: traction is then applied slowly. It has been widely used, but is not accepted as a substitute for obstetric forceps.

Back  -    New Search

vagal (vay-gl) adj.

relating to the vagus nerve.

Back  -    New Search

vagin- (vagino-) prefix

denoting the vagina.

Back  -    New Search

vagina (v-jy-n) n.

the lower part of the female reproductive tract: a muscular tube, lined with mucous membrane, connecting the cervix of the uterus to the exterior. It receives the erect penis during coitus.
—vaginal adj.

Back  -    New Search

vaginismus (vaj-i-niz-ms) n.

sudden and painful contraction of the muscles surrounding the vagina, usually in response to the vulva or vagina being touched. The condition may be associated with fear of or aversion to coitus; other causative factors include vaginal injury and dryness of the lining membrane of the vagina. See also DYSPAREUNIA.

Back  -    New Search

vaginitis (vaj-i-ny-tis) n.

inflammation of the vagina, which may be caused by infection (commonly with Trichomonas vaginalis), dietary deficiency, or poor hygiene. There is often itching (see PRURITIS), increased vaginal discharge, and pain on passing urine. postmenopausal (or atrophic ) v. vaginitis caused by a deficiency of female sex hormones.

Back  -    New Search

vaginoplasty (colpoplasty) (v-jy-noh-plasti) n.

a tissue-grafting operation on the vagina.

Back  -    New Search

vaginoscope (vaj-in-oh-skohp) n.

see COLPOSCOPE.

Back  -    New Search

vago- prefix

denoting the vagus nerve.

Back  -    New Search

vagotomy (vag-ot-mi) n.

the surgical cutting of any of the branches of the vagus nerve. This is usually performed to reduce secretion of acid and pepsin by the stomach in order to cure a peptic ulcer.

Back  -    New Search

vagus nerve (vay-gs) n.

the tenth cranial nerve (X), which supplies motor nerve fibres to the muscles of swallowing and parasympathetic fibres to the heart and organs of the chest cavity and abdomen. Sensory branches carry impulses from the viscera and the sensation of taste from the mouth.

Back  -    New Search

valgus (val-gs) adj.

describing any deformity that displaces the hand or foot away from the midline. See HALLUX (VALGUS), KNOCK-KNEE (GENU VALGUM), TALIPES (VALGUS).

Back  -    New Search

valine (vay-leen) n.

an essential amino acid. See also AMINO ACID.

Back  -    New Search

Valium (val-im) n.

see DIAZEPAM.

Back  -    New Search

valve (valv) n.

a structure found in some tubular organs or parts that restricts the flow of fluid within them to one direction only (see CUSP). Valves are important structures in the heart, veins, and lymphatic vessels (see illustration). See also MITRAL VALVE, TRICUSPID VALVE, SEMILUNAR VALVE.

Back  -    New Search

valvotomy (valvulotomy) (val-vot-mi) n.

surgical cutting through a valve. The term is usually used to describe the operation to relieve obstruction caused by stenosed valves in the heart (e.g. mitral v. ). percutaneous balloon v. balloon dilatation of narrowed valves after introduction of a balloon via a catheter passed up a great vessel.

Back  -    New Search

valvula (val-vew-l) n. (pl.valvulae)

a small valve. valvulae conniventes circular folds of mucous membrane in the small intestine.

Back  -    New Search

valvulitis (val-vew-ly-tis) n.

inflammation of one or more valves, particularly the heart valves. This is most often due to rheumatic fever (see ENDOCARDITIS).

Back  -    New Search

vancomycin (vank-oh-my-sin) n.

an antibiotic, derived from the bacterium Streptomyces orientalis, that is effective against most Gram-positive organisms. It is given by intravenous infusion for infections due to strains that are resistant to other antibiotics. Trade name: Vancocin .

Back  -    New Search

van den Bergh's test (van-den-bergz) n.

a test to determine whether jaundice in a patient is due to haemolysis or to disease of the liver or bile duct. [A. A. H. van den Bergh (1869–1943), Dutch physician]

Back  -    New Search

vaporizer (vay-per-l-zer) n.

a piece of equipment for producing an extremely fine mist of liquid droplets by forcing a jet of liquid through a narrow nozzle with a jet of air. See also AEROSOL.

Back  -    New Search

Vaquez-Osler disease (vak-ay ohs-ler) n.

see POLYCYTHAEMIA (VERA). [L. H. Vaquez (1860–1936), French physician; Sir W. Osler (1849–1919), Canadian physician]

Back  -    New Search

varicectomy (va-ri-sek-tmi) n.

see PHLEBECTOMY.

Back  -    New Search

varicella (va-ri-sel-) n.

see CHICKENPOX.

Back  -    New Search

varices (va-ri-seez) pl.

see VARICOSE VEINS.

Back  -    New Search

varicocele (va-ri-koh-seel) n.

a collection of dilated veins in the spermatic cord. It usually produces no symptoms apart from occasional aching discomfort. In some cases varicocele is associated with oligospermia, which can be improved by surgical correction of the varicocele (varicocelectomy ).

Back  -    New Search

varicose veins (va-ri-kohs) pl. n.

veins that are distended, lengthened, and tortuous. The superficial veins of the legs are most commonly affected; other sites include the oesophagus (see OESOPHAGEAL VARICES) and testes (see VARICOCELE). There is an inherited tendency to varicose veins but obstruction to blood flow is responsible in some cases. Treatment includes elastic support and sclerotherapy, but stripping or excision is required in some cases. Medical name: varices .

Back  -    New Search

varicotomy (va-ri-kot-mi) n.

incision into a varicose vein (see PHLEBECTOMY).

Back  -    New Search

variola (v-ry--l) n.

see SMALLPOX.

Back  -    New Search

varioloid (vair-i--loid)

1 n. a mild form of smallpox in people who have previously had smallpox or have been vaccinated against it.

2 adj. resembling smallpox.
Top

Back  -    New Search

varix (vair-iks) n. (pl. varices)

a single varicose vein.

Back  -    New Search

varus (vair-s) adj.

describing any deformity that displaces the hand or foot towards the midline. See BOW-LEGS (GENU VARUM), HALLUX (VARUS), TALIPES (VARUS).

Back  -    New Search

vas- (vaso-) prefix

denoting 1 vessels, especially blood vessels.

2 the vas deferens.
Top

Back  -    New Search

vasa efferentia (vay-s ef-er-en-shi) pl. n. (sing. vas efferens)

the many small tubes that conduct spermatozoa from the testis to the epididymis.

Back  -    New Search

vasa vasorum (vas-or-m) pl. n.

the tiny arteries and veins that supply the walls of blood vessels.

Back  -    New Search

vascular (vas-kew-ler) adj.

relating to or supplied with blood vessels. v. system see CARDIOVASCULAR SYSTEM.

Back  -    New Search

vascularization (vas-kew-ler-l-zay-shn) n.

the development of blood vessels (usually capillaries) within a tissue.

Back  -    New Search

vasculitis (vas-kew-ly-tis) n.

see ANGIITIS.

Back  -    New Search

vas deferens (vas def-er-nz) n. (pl. vasa deferentia)

either of a pair of ducts that conduct spermatozoa from the epididymis to the urethra on ejaculation.

Back  -    New Search

vasectomy (v-sek-tmi) n.

the surgical operation of severing the vas deferens. Bilateral vasectomy causes sterility and is an increasingly popular means of birth control.

Back  -    New Search

vaso-prefix.

see VAS-.

Back  -    New Search

vasoactive (vay-zoh-ak-tiv) adj.

affecting the diameter of blood vessels, especially arteries. Examples of vasoactive agents are emotion, pressure, carbon dioxide, and temperature.

Back  -    New Search

vasoconstriction (vay-zoh-kn-strik-shn) n.

a decrease in the diameter of blood vessels, especially arteries.

Back  -    New Search

vasoconstrictor (vay-zoh-kn-strik-ter) n.

an agent that causes narrowing of the blood vessels and therefore a decrease in blood flow. Examples are metaraminol and phenylephrine. Vasoconstrictors are used to raise the blood pressure in disorders of the circulation, shock, or severe bleeding and to maintain blood pressure during surgery.

Back  -    New Search

vasodilatation (vay-zoh-dy-l-tay-shn) n.

an increase in the diameter of blood vessels, especially arteries.

Back  -    New Search

vasodilator (vay-zoh-dy-lay-ter) n.

a drug that causes widening of the blood vessels and therefore an increase in blood flow. Vasodilators are used to lower blood pressure in cases of hypertension. coronary v. a drug, such as glyceryl trinitrate or pentaerythritol, that increases the blood flow through the heart and is used to relieve and prevent angina. peripheral v. a drug, such as an alpha blocker or nicotinyl, that affects the blood vessels of the limbs and is used to treat conditions of poor circulation.

Back  -    New Search

vaso-epididymostomy (vay-zoh-epi-did-i-mos-tmi) n.

the operation of joining the vas deferens to the epididymis in a side-to-side manner in order to bypass an obstruction in the epididymis to the passage of sperm from the testis.

Back  -    New Search

vasoligation (vay-zoh-ly-gay-shn) n.

the surgical tying of the vas deferens. This is performed to prevent infection spreading from the urinary tract causing recurrent epididymitis.

Back  -    New Search

vasomotion (vay-zoh-moh-shn) n.

an increase or decrease in the diameter of blood vessels, particularly the arteries. See VASOCONSTRICTION, VASODILATATION.

Back  -    New Search

vasomotor (vay-zoh-moh-ter) adj.

controlling the muscular walls of blood vessels, especially arteries, and therefore their diameter. v. centre a collection of nerve cells in the medulla oblongata that brings about reflex changes in the rate of the heartbeat and in the diameter of blood vessels, so that the blood pressure can be adjusted. v. nerve any nerve, usually belonging to the autonomic nervous system, that controls the circulation of blood through blood vessels by its action on the muscle fibres within their walls or its action on the heartbeat. v. symptoms subjective sensations experienced by women around the time of the menopause, often described as explosions of heat, mostly followed by profuse sweating. Physiological changes include peripheral vasodilatation, tachycardia with normal blood pressure, and raised skin temperature with normal body temperature.

Back  -    New Search

vasopressin (antidiuretic hormone, ADH) (vay-zoh-press-in) n.

a hormone, released by the pituitary gland, that increases the reabsorption of water by the kidney and causes constriction of blood vessels. It is administered either nasally or by injection to treat diabetes insipidus. Intravenous injections of vasopressin are used to control bleeding from oesophageal varices.

Back  -    New Search

vasopressor (vay-zoh-press-er) adj.

stimulating the contraction of blood vessels and therefore bringing about an increase in blood pressure.

Back  -    New Search

vasospasm (vay-zoh-spazm) n.

see RAYNAUD'S DISEASE.

Back  -    New Search

vasovagal (vay-zoh-vay-gl) adj.

relating to the action of impulses in the vagus nerve on the circulation. The vagus reduces the rate at which the heart beats, and so lowers its output. v. attack excessive activity of the vagus nerve, causing slowing of the heart and a fall in blood pressure, which leads to fainting. See SYNCOPE.

Back  -    New Search

vasovasostomy (vay-zoh-v-sos-tmi) n.

the surgical operation of reanastomosing the vas deferens after previous vasectomy: the reversal of vasectomy, undertaken to restore fertility.

Back  -    New Search

vasovesiculitis (vay-zoh-ve-sik-yoo-ly-tis) n.

inflammation of the seminal vesicles and vas deferens. This usually occurs in association with prostatitis and causes pain in the perineum, groin, and scrotum and a high temperature.

Back  -    New Search

vector (vek-ter) n.

an animal, usually an insect or a tick, that transmits parasitic microorganisms – and therefore the diseases they cause – from person to person or from infected animals to human beings.

Back  -    New Search

vectorcardiography (vek-ter-kar-di-og-rfi) n.

see ELECTROCARDIOGRAPHY.

Back  -    New Search

vegetation (vej-i-tay-shn) n.

(in pathology) an abnormal outgrowth from a membrane. In ulcerative endocarditis, such outgrowths, consisting of fibrin with enmeshed blood cells, are found on the membrane lining the heart valves.

Back  -    New Search

vegetative (vej-i-t-tiv) adj.

1 relating to growth and nutrition rather than to reproduction.

2 functioning unconsciously; autonomic.
Top

Back  -    New Search

vehicle (vee-ikl) n.

(in pharmacy) any substance, such as sterile water or dextrose solution, that acts as the medium in which a drug is administered.

Back  -    New Search

vein (vayn) n.

a blood vessel conveying blood towards the heart. All veins except the pulmonary vein carry deoxygenated blood from the tissues to the vena cava. Veins contain valves that assist the flow of blood back to the heart. (See illustration.) Anatomical name: vena.

—venous (vee-ns) adj.

Back  -    New Search

vena cava (vee-n kay-v) n. (pl. venae cavae)

either of the two main veins, conveying blood from the other veins to the right atrium of the heart. inferior v. c. the vein that receives blood from parts of the body below the diaphragm. superior v. c. the vein that drains blood from the head, neck, thorax, and arms.

Back  -    New Search

vene- (veno-) prefix

denoting veins.

Back  -    New Search

venene (ven-een) n.

a mixture of two or more venoms: used to produce antiserum against venoms (antivenene).

Back  -    New Search

venepuncture (venipuncture) (ven-i-punk-cher) n.

the puncture of a vein for any therapeutic purpose; for example, to extract blood for laboratory tests. See also PHILEBOTOMY.

Back  -    New Search

venereal disease (VD) (vin-eer-il) n.

see SEXUALLY TRANSMITTED DISEASE.

Back  -    New Search

venesection (ven-i-sek-shn) n.

see PHLEBOTOMY.

Back  -    New Search

veno- prefix

see VENE-.

Back  -    New Search

venoclysis (vi-nok-li-sis) n.

the continuous infusion into a vein of saline or other solution.

Back  -    New Search

venography (phlebography) (vi-nog-rfi) n.

X-ray examination to demonstrate the anatomy of veins in a particular region of the body. A radiopaque contrast medium is injected into a vein and X-ray photographs (venograms ) are taken as the medium flows towards the heart. See also ANGIOGRAPHY.

Back  -    New Search

venom (ven-m) n.

the poisonous material produced by snakes, scorpions, etc. Some venoms produce no more than local pain and swelling; others can prove lethal.

Back  -    New Search

ventilation (ven-ti-lay-shn) n.

the passage of air into and out of the respiratory tract. In the alveoli of the lungs gas exchange is most efficient when matched by an adequate blood flow (perfusion). Ventilation/perfusion imbalance is an important cause of anoxia and cyanosis.

Back  -    New Search

ventilator (ven-ti-lay-ter) n.

1 a device used to ensure a supply of fresh air.

2 equipment that is manually or mechanically operated to maintain a flow of air into and out of the lungs of a patient who is unable to breathe normally. See also RESPIRATOR.
Top

Back  -    New Search

ventouse (von-toos) n.

see VACUUM EXTRACTOR.

Back  -    New Search

ventricle (ven-trl) adj.

relating to or situated at or close to the front of the body or to the anterior part of an organ.

Back  -    New Search

ventricle (ven-trik-l) n.

1 either of the two lower chambers of the heart. The left ventricle receives blood from the pulmonary vein and pumps it into the aorta. The right ventricle pumps blood from the venae cavae into the pulmonary artery.

2 one of the four fluid-filled cavities within the brain. The paired first and second ventricles (lateral ventricles) communicate with the third ventricle. This leads to the fourth ventricle in the hindbrain, which is continuous with the spinal canal. Cerebrospinal fluid circulates through all the cavities.
Top

—ventricular (ven-trik-yoo-ler) adj.

Back  -    New Search

ventricul- (ventriculo-) prefix

denoting a ventricle (of the brain or heart).

Back  -    New Search

ventricular folds pl. n.

see VOCAL FOLDS.

Back  -    New Search

ventricular septal defect n.

see SEPTAL DEFECT.

Back  -    New Search

ventriculitis (ven-trik-yoo-ly-tis) n.

inflammation in the ventricles of the brain, usually caused by infection.

Back  -    New Search

ventriculoatriostomy (ven-trik-yoo-loh-ay-tri-ost-mi) n.

an operation for the relief of raised pressure due to the build-up of cerebrospinal fluid that occurs in hydrocephalus.

Back  -    New Search

ventriculography (ven-trik-yoo-log-rfi) n.

X-ray examination of the ventricles of the brain after the introduction of a contrast medium. This procedure has been largely made redundant by CT and MRI scanning.

Back  -    New Search

ventriculoscopy (ven-trik-yoo-losk-pi) n.

observation of the ventricles of the brain through a fibre-optic instrument. See ENDOSCOPE, FIBRE OPTICS.

Back  -    New Search

ventriculostomy (ven-trik-yoo-lost-mi) n.

an operation to introduce a hollow needle (cannula) into one of the lateral ventricles of the brain. This may be done to relieve raised intracranial pressure, to obtain cerebrospinal fluid for examination, or to introduce antibiotics or contrast material for X-ray examination.

Back  -    New Search

ventro– prefix

denoting 1 ventral.

2 the abdomen.
Top

Back  -    New Search

ventrofixation (ven-troh-fiks-ay-shn) n.

see VENTROSUSPENSION.

Back  -    New Search

ventrosuspension (ventrofixation) (ven-troh-sus-pen-shn) n.

surgical fixation of a displaced uterus to the anterior abdominal wall. This may be achieved by shortening the round ligaments at their attachment either to the uterus or to the abdominal wall.

Back  -    New Search

venule (ven-yool) n.

a minute vessel that drains blood from the capillaries.

Back  -    New Search

verapamil (v-rap--mil) n.

a calcium antagonist administered by mouth in the treatment of essential hypertension, angina, and arrhythmia. Trade names: Cordilox , Securon , Univer .

Back  -    New Search

verbigeration (ver-bij-er-ay-shn) n.

repetitive utterances of the same words over and over again. It is most common in institutionalized schizophrenics.

Back  -    New Search

vermicide (verm-i-syd) n.

a chemical agent used to destroy parasitic worms living in the intestine. Compare VERMIFUGE.

Back  -    New Search

vermiform appendix (verm-i-form) n.

see APPENDIX.

Back  -    New Search

vermifuge (verm-i-fewj) n.

any drug or chemical agent used to expel worms from the intestine. See also ANTHELMINTIC.

Back  -    New Search

vermix (ver-miks) n.

the vermiform appendix.

Back  -    New Search

vernal conjunctivitis (ver-nl) n.

see CONJUNCTIVITIS.

Back  -    New Search

vernix caseosa (ver-niks kay-si-oh-s) n.

the layer of greasy material that covers the skin of a fetus or newborn baby. It is produced by the sebaceous glands and contains skin scales and fine hairs.

Back  -    New Search

verruca (plantar wart) (ver-oo-k) n.

(pl. verrucae) see WART.

Back  -    New Search

verrucous carcinoma (ver-oo-ks) n.

an indolent preinvasive wartlike carcinoma of the oral cavity, which is associated with chewing tobacco.

Back  -    New Search

version (ver-shn) n.

a manoeuvre to alter the position of a fetus in the uterus to facilitate delivery. For example, the fetus may be turned from a transverse to a longitudinal position or from a buttocks-first to a head-first presentation. See also CEPHALIC VERSION.

Back  -    New Search

vertebra (ver-tib-r) n. (pl. vertebrae)

one of the 33 bones of which the backbone is

composed. Each vertebra typically consists of a body , from the back of which arises an arch of bone (the neural arch ) enclosing a cavity through which the spinal cord passes. Individual vertebrae are bound together by ligaments and intervertebral discs.
—vertebral adj.

Back  -    New Search

vertebral column (ver-tib-rl) n.

see BACKBONE.

Back  -    New Search

vertex (ver-teks) n.

the crown of the head.

Back  -    New Search

vertigo (vert-i-goh) n.

a disabling sensation in which the affected individual feels that either he himself or his surroundings are in a state of constant movement. It is a symptom of disease either in the labyrinth of the inner ear or in the vestibular nerve or its nuclei in the brain-stem.

Back  -    New Search

vesical (ves-ikl) adj.

relating to or affecting a bladder, especially the urinary bladder.

Back  -    New Search

vesicant (ves-i-knt) n.

an agent that causes blistering of the skin.

Back  -    New Search

vesicle (ves-ikl) n.

1 a very small blister in the skin that contains serum. Vesicles occur in a variety of skin disorders, including eczema and herpes.

2 (in anatomy) any small bladder, especially one filled with fluid.
Top

—vesicular (ves-ik-yoo-ler) adj.

Back  -    New Search

vesico- prefix

denoting the urinary bladder.

Back  -    New Search

vesicofixation (ves-i-koh-fiks-ay-shn) n.

see CYSTOPEXY.

Back  -    New Search

vesicostomy (ves-i-kos-tmi) n.

the surgical creation of an artificial channel between the bladder and the skin surface for the passage of urine. It is sometimes combined with closure of the urethra.

Back  -    New Search

vesicoureteric reflux (ves-i-koh-yoor-i-te-rik) n.

the backflow of urine from the bladder into the ureters, due to defective valves. Infection is conveyed to the kidneys, causing recurrent attacks of acute pyelonephritis and scarring of the kidneys in childhood.

Back  -    New Search

vesicovaginal (ves-i-koh-v-jy-nl) adj.

relating to the bladder and vagina.

Back  -    New Search

vesicular breath sounds pl. n.

normal breath sounds, which may be increased or decreased in disease states.

Back  -    New Search

vesicular mole n.

see HYDATIDIFORM MOLE.

Back  -    New Search

vesiculitis (ve-sik-yoo-ly-tis) n.

inflammation of the seminal vesicles. See VASOVESICULITIS.

Back  -    New Search

vesiculography (ve-sik-yoo-log-rfi) n.

X-ray examination of the seminal vesicles. This is usually performed by injecting radiopaque contrast material into the exposed vasa deferentia.

Back  -    New Search

vessel (ves-l) n.

a tube conveying a body fluid, especially a blood vessel or a lymphatic vessel.

Back  -    New Search

vestibular glands (ves-tib-yoo-ler) pl. n.

the two pairs of glands that open at the junction of the vagina and vulva. Their function is to lubricate the entrance to the vagina during coitus.

Back  -    New Search

vestibular nerve n.

the division of the vestibulocochlear nerve that carries impulses from the semicircular canals, utricle, and saccule of the inner ear, conveying information about posture, movement, and balance.

Back  -    New Search

vestibule (vest-i-bewl) n.

(in anatomy) a cavity situated at the entrance to a hollow part. The vestibule of the ear is the cavity of the bony labyrinth that contains the saccule and utricle.

Back  -    New Search

vestibulocochlear nerve (acoustic nerve, auditory nerve) (ves-tib-yoo-loh-kok-li-er) n.

the eighth cranial nerve (VIII), responsible for carrying sensory impulses from the inner ear to the brain. It has two branches (see COCHLEAR NERVE, VESTIBULAR NERVE).

Back  -    New Search

vestigial (ves-tij-il) adj.

existing only in a rudimentary form. The term is applied to organs whose structure and function have diminished during the course of evolution.

Back  -    New Search

viable (vy-bl) adj.

capable of living a separate existence. The legal age of viability of a fetus is 24 weeks, but some fetuses now survive birth at an even earlier age.

Back  -    New Search

Vibramycin (vy-br-my-sin) n.

see DOXY-CYCLINE.

Back  -    New Search

Vibrio (vib-ri-oh) n.

a genus of Gram-negative motile comma-shaped bacteria widely distributed in soil and water. V. cholerae the species that causes cholera.

Back  -    New Search

vicarious (vik-air-is) adj.

describing an action or function performed by an organ not normally involved in the function. v. menstruation a rare disorder in which monthly bleeding occurs from places other than the vagina, such as the sweat glands, breasts, nose, or eyes.

Back  -    New Search

vidarabine (vid-a-r-been) n.

an antiviral drug that is used to treat herpes simplex, herpes zoster (shingles), and cytomegalo-virus infections. Vidarabine is administered by intravenous infusion. Trade name: Vira-A .

Back  -    New Search

villus (vil-s) n. (pl. villi)

one of many short finger-like processes that project from the surfaces of some membranes. arachnoid v. see ARACHNOID. chorionic v. any of the folds of the chorion from which the fetal part of the placenta is formed. They provide an extensive area for the exchange of oxygen, nutrients, etc., between maternal and fetal blood. intestinal v. any of numerous projections that line the small intestine. Each contains a network of blood capillaries and a lacteal. Their function is to absorb the products of digestion and they greatly increase the surface area over which this can take place.

Back  -    New Search

vinblastine (vin-blas-teen) n.

a cytotoxic drug that is given by intravascular injection mainly in the treatment of cancers of the lymphatic system, such as Hodgkin's disease. It is highly toxic. Trade name: Velbe .

Back  -    New Search

vinca alkaloid (ving-k) n.

one of a group of antimitotic drugs (see CYTOTOXIC DRUG) derived from the periwinkle (Vinca rosea). Vinca alkaloids are used especially to treat leukaemias and lymphomas; they include vinblastine, vincristine, and vin-desine.

Back  -    New Search

Vincent's angina (vin-snts) n.

see ULCER-ATIVE GINGIVITIS. [H. Vincent (1862–1950), French physician]

Back  -    New Search

vincristine (vin-kris-teen) n.

a cytotoxic drug with uses and side-effects similar to those of vinblastine. Trade name: Oncovin .

Back  -    New Search

vindesine (vin-d-seen) n.

a cytotoxic drug with similarities to vinblastine and vincristine. Trade name: Eldisine .

Back  -    New Search

VIP (vasoactive intestinal peptide) n.

a protein produced by cells of the pancreas. Large amounts of this protein cause severe diarrhoea.

Back  -    New Search

vipoma (vy-poh-m) n.

a tumour of islet cells of the pancreas that secrete VIP.

Back  -    New Search

viraemia (vyr-ee-mi) n.

the presence in the blood of virus particles.

Back  -    New Search

viral pneumonia (vy-rl) n.

an acute infection of the lung caused by a virus, such as respiratory syncytial virus, adenovirus, influenza and parainfluenza viruses, or an enterovirus. It is characterized by headache, fever, muscle pain, and a cough that produces a thick sputum. The pneumonia often occurs with or subsequent to a systemic viral infection.

Back  -    New Search

virilism (vi-ril-izm) n.

the development in a female of increased body hair, muscle bulk, deepening of the voice, and male psychological characteristics.

Back  -    New Search

virilization (vi-ri-ly-zay-shn) n.

the most extreme result of excessive androgen production (hyperandrogenism) in women. It is characterized by temporal balding, a male body form, muscle bulk, deepening of the voice, enlargement of the clitoris, and hirsutism. Virilization in prepubertal boys may be caused by some tumours (see LEYDIG TUMOUR) or the adrenogenital syndrome.

Back  -    New Search

virology (vyr-ol-ji) n.

the science of viruses. See also MICROBIOLOGY.

Back  -    New Search

virulence (vi-rew-lns) n.

the disease-producing (pathogenic) ability of a microorganism. See also ATTENUATION.

Back  -    New Search

virus (vy-rs) n.

a minute particle that is capable of replication but only within living cells. Viruses are too small to be visible with a light microscope or to be trapped by filters. They infect animals, plants, and microorganisms. Viruses cause many diseases, including herpes, influenza, mumps, polio, AIDS, and rabies. Antiviral drugs are effective against some of them, and many viral diseases are controlled by means of vaccines.
—viral adj.

Back  -    New Search

viscera (vis-er-) pl. n. (sing. viscus)

the organs within the body cavities, especially the organs of the abdominal cavities.
—visceral (vis-er-l) adj.

Back  -    New Search

visceral pouch

see PHARYNGEAL POUCH.

Back  -    New Search

viscero- prefix

denoting the viscera.

Back  -    New Search

visceroptosis (vis-er-op-toh-sis) n.

downward displacement of the abdominal organs.

Back  -    New Search

viscid (vis-id) adj.

glutinous and sticky.

Back  -    New Search

viscus (vis-ks) n.

see VISCERA.

Back  -    New Search

visual acuity (vizh-yoo-l) n.

sharpness of vision. The commonest way of assessing visual acuity is the Snellen chart.

Back  -    New Search

visual field n.

the area in front of the eye in any part of which an object can be seen without moving the eye.

Back  -    New Search

visual purple n.

see RHODOPSIN.

Back  -    New Search

vital capacity (vy-t'l) n.

the maximum volume of air that a person can exhale after maximum inhalation.

Back  -    New Search

vital centre n.

any of the collections of nerve cells in the brain that act as governing centres for different vital body functions, such as breathing, blood pressure, etc.

Back  -    New Search

Vitallium (vy-tal-im) n.

Trademark. an alloy of chromium and cobalt that is used in instruments, prostheses, surgical appliances, and dentures.

Back  -    New Search

vital statistics pl. n.

statistics relating to the births, marriages, deaths, and incidence of disease within a population.

Back  -    New Search

vitamin (vit--min) n.

any of a group of substances that are required, in very small amounts, for healthy growth and development: they cannot be synthesized by the body and are therefore essential constituents of the diet. Vitamins are divided into two groups, according to whether they are soluble in water or fat.

Back  -    New Search

vitamin A (retinol) n.

a fat-soluble vitamin that occurs preformed in foods of animal origin (especially milk products, egg yolk, and liver) and is formed in the body from the pigment ß-carotene, present in some vegetable foods (for example cabbage, lettuce, and carrots). Retinol is essential for growth, vision in dim light, and the maintenance of soft mucous tissue. A deficiency causes stunted growth, night blindness, xerophthalmia, keratomalacia, and eventual blindness. Recommended daily intake: 750 µg retinol equivalents.

Back  -    New Search

vitamin B n.

any one of a group of water-soluble vitamins that are often found together in the same kinds of food, such as liver, yeast, and eggs, and all function as coenzymes. B_1 (thiamin , aneurine ) a vitamin deficiency of which leads to beriberi. Recommended daily intake: 1 mg. B_2 (riboflavin ) a vitamin important in tissue respiration. A deficiency causes ariboflavinosis. Recommended daily intake: 1.7 mg. B_6 (pyridoxine) a vitamin from which the coenzyme pyridoxal phosphate is formed. Deficiency is very rare. B_12 (cyanocobalamin) a vitamin that can be absorbed only in the presence of intrinsic factor, secreted in the stomach. A deficiency can lead to pernicious anaemia and degeneration of the nervous system. Recommended daily intake: 3–4 µg. See also BIOTIN, FOLIC ACID, NICOTINIC ACID, PANTOTHENIC ACID.

Back  -    New Search

vitamin C (ascorbic acid) n.

a water-soluble vitamin with antioxidant properties that is essential in maintaining healthy connective tissues. A deficiency of vitamin C leads to scurvy. Recommended daily intake: 30 mg; rich sources are citrus fruits and vegetables.

Back  -    New Search

vitamin D n.

a fat-soluble vitamin that enhances the absorption of calcium and phosphorus from the intestine and promotes their deposition in the bone. D_2 (ergocalciferol , calciferol ) a form obtained from the diet; good sources are fatty fish, eggs, and margarine. D_3 (cholecalciferol) a form manufactured in the skin in the presence of sunlight. A deficiency of vitamin D leads to rickets and osteomalacia. Recommended daily intake: 10 µg (for a child up to five years); 2.5 µg (thereafter).

Back  -    New Search

vitamin E n.

any of a group of chemically related fat-soluble compounds (tocopherols and tocotrienols ) that have antioxidant properties and are thought to stabilize cell membranes. Good sources of the vitamin are vegetable oils, eggs, butter, and wholemeal cereals. It is fairly widely distributed in the diet and a deficiency is therefore unlikely.

Back  -    New Search

vitamin K n.

a fat-soluble vitamin occurring in two main forms – phytomenadione and menaquinone – essential for the normal clotting of blood. A dietary deficiency does not often occur as the vitamin is synthesized by bacteria in the large intestine and is widely distributed in green leafy vegetables and meat.

Back  -    New Search

vitelliform degeneration (Best's disease) (vy-tel-i-form) n.

degeneration of the macula of the eye that is inherited as a dominant characteristic and usually starts in childhood. There is widespread abnormality of retinal pigment epithelium (see RETINA) with the accumulation of a yellowish material, especially in the macular area.

Back  -    New Search

vitellus (vi-tel-s) n.

the yolk of an ovum.

Back  -    New Search

vitiligo (vit-i-ly-goh) n.

a common disorder in which symmetrical white or pale macules appear on the skin. It affects all races, but is more conspicuous in dark-skinned races. Vitiligo is an autoimmune disease and is usually progressive, although spontaneous repigmentation may occur.

Back  -    New Search

vitrectomy (vi-trek-tmi) n.

the removal of all or part of the vitreous humour of the eye, including vitreous haemorrhage. It is often necessary in surgery to repair a detached retina.

Back  -    New Search

vitreous detachment (vit-ri-s) n.

the separation of the vitreous humour from the underlying retina. This is a normal ageing process, but it is also more common in such conditions as diabetes and severe myopia. It can sometimes cause a tear in the retina and lead to retinal detachment.

Back  -    New Search

vitreous humour (vitreous body) n.

the transparent jelly-like material that fills the chamber behind the lens of the eye.

Back  -    New Search

vitritis (vi-try-tis) n.

inflammation within the vitreous humour of the eye.

Back  -    New Search

vivisection (viv-i-sek-shn) n.

a surgical operation on a living animal for experimental purposes.

Back  -    New Search

vocal folds (vocal cords) (voh-kl) pl. n.

the two folds of tissue protruding from the sides of the larynx to form a narrow slit (glottis) across the air passage (see illustration). Their controlled interference with the expiratory air flow produces audible vibrations that make up speech, song, and all other vocal noises.

Back  -    New Search

vocal fremitus n.

see FREMITUS.

Back  -    New Search

vocal resonance n.

the sounds heard through the stethoscope when the patient speaks. These are normally just audible but they become much louder (bron-chophony ) if the lung under the stethoscope is consolidated. Vocal resonance is lost over pleural fluid except at its upper surface, when it has a bleating quality (aegophony ). See also PECTORILOQUY.

Back  -    New Search

volar (voh-ler) adj.

relating to the palm of the hand or the sole of the foot (the vola ).

Back  -    New Search

volatile (vol--tyl) adj.

describing a liquid that evaporates at room temperature.

Back  -    New Search

volition (vl-ish-n) n.

the act of or capacity for exercizing the will.

Back  -    New Search

Volkmann's contracture (fohlk-mahnz) n.

shrinkage and shortening of muscles due to inadequate blood supply. This arises if the blood supply is interrupted by pressure on the blood vessels from a fracture fragment, or from raised pressure due to compartment syndrome, or by pressure from constricting bandages or plaster casts. [R. von Volkmann (1830–89), German surgeon]

Back  -    New Search

volsellum (vulsellum) (vol-sel-m) n.

surgical forceps with clawlike hooks at the ends of both blades.

Back  -    New Search

volt (vohlt) n.

the SI unit of electric potential. Symbol: V.

Back  -    New Search

voluntary admission (vol-n-ter-i) n.

entry of a patient into a psychiatric hospital with his (or her) agreement. Compare COMPULSORY ADMISSION.

Back  -    New Search

voluntary muscle n.

see STRIATED MUSCLE.

Back  -    New Search

volvulus (vol-vew-ls) n.

twisting of part of the digestive tract, usually leading to partial or complete obstruction and sometimes reducing the blood supply, causing gangrene.

Back  -    New Search

vomer (voh-mer) n.

a thin plate of bone that forms part of the nasal septum.

Back  -    New Search

vomica (vom-ik-) n.

1 an abnormal cavity in an organ, usually a lung, sometimes containing pus.

2 the abrupt expulsion from the mouth of a large quantity of pus or decaying matter originating in the throat or lungs.
Top

Back  -    New Search

vomit (vom-it)

1 vb. to eject the contents of the stomach through the mouth (see VOMITING).

2 n. the contents of the stomach ejected during vomiting. Medical name: vomitus .
Top

Back  -    New Search

vomiting (vom-it-ing) n.

the reflex action of ejecting the contents of the stomach through the mouth. Vomiting is controlled by a special centre in the brain that may be stimulated by drugs acting directly on it or by impulses transmitted from the stomach (e.g. after ingesting irritating substances), the intestine (e.g. in intestinal obstruction), or from the inner ear (in motion sickness). Medical name: emesis .

Back  -    New Search

von Recklinghausen's disease (von rek-ling-how-znz) n.

1 a syndrome due to hyperparathyroidism, characterized by loss of mineral from bones, which become weakened and fracture easily, and formation of kidney stones. Medical name: osteitis fibrosa.

2 see NEUROFIBROMATOSIS. [F. D. von Recklinghausen (1833–1910), German pathologist]
Top

Back  -    New Search

von Willebrand's disease (von wil-i-brandz) n.

an inherited disorder of the blood characterized by episodes of spontaneous bleeding similar to haemophilia. It may or may not be associated with deficiency of coagulation factor VIII. [A. von Willebrand (1870–1949), Swedish physician]

Back  -    New Search

VSD n.

see (VENTRICULAR) SEPTAL DEFECT.

Back  -    New Search

vulsellum (vul-sel-m) n.

see VOLSELLUM.

Back  -    New Search

vulv- (vulvo-) prefix

denoting the vulva.

Back  -    New Search

vulva (vul-v) n.

the female external genitalia. Two pairs of fleshy folds (see LABIUM) surround the openings of the vagina and urethra and extend forward to the clitoris. See also VESTIBULAR GLANDS.

Back  -    New Search

vulvectomy (vul-vek-tmi) n.

surgical removal of the vulva. simple v. excision of the labia majora, labia minora, and clitoris to eradicate a nonmalignant growth. radical v. excision of the labia majora and minora, the clitoris, and all regional lymph nodes on both sides, together with the skin covering these areas. It is carried out for a malignant growth.

Back  -    New Search

vulvitis (vul-vy-tis) n.

inflammation of the vulva, which is often accompanied by intense itching (see PRURITUS).

Back  -    New Search

vulvovaginitis (vul-voh-vaj-i-ny-tis) n.

inflammation of the vulva and vagina (see PRURITUS, VAGINITIS).

Back  -    New Search

W

Waardenburg's syndrome (vah-den-bergz) n.

an inherited form of deafness accompanied by a characteristic white forelock of hair and multiple colours within the irises of the eyes. It is inherited as an autosomal dominant disease, although severity is variable. [P. J. Waardenburg (1886–1979), Dutch ophthalmologist]

Back  -    New Search

wafer (way-fer) n.

a thin sheet made from moistened flour, formerly used to enclose a powdered medicine that is taken by mouth.

Back  -    New Search

waiting list (wayt-ing) n.

a list of the names of patients who are awaiting admission to hospital after having been assessed either as an out-patient or on a domiciliary consultation involving a specialist. In general the patients are offered places in the order in which their names were placed on the list.

Back  -    New Search

Waldeyer's ring (vahl-dy-erz) n.

the ring of lymphoid tissue formed by the tonsils. [H. W. G. von Waldeyer (1836–1921), German anatomist]

Back  -    New Search

walking distance (wawk-ing) n.

the measured distance that a patient can walk before he or she is stopped by pain in the muscles, usually the calf muscles. It is a useful estimate of the degree of impairment of the blood supply. See CLAUDICATION.

Back  -    New Search

Wallerian degeneration (wol-eer-an) n.

fatty degeneration of a ruptured nerve fibre that occurs within the nerve sheath distal to the point of severance. [A. V. Waller (1816–70), British physician]

Back  -    New Search

Wangensteen tube (wang-n-steen) n.

a tube with a suction apparatus that is passed into the stomach through the nose and is used to drain the contents of the stomach and duodenum to relieve abdominal distention. [O. H. Wangensteen (1898–1980), US surgeon]

Back  -    New Search

ward manager (wawd man--jer) n.

a person responsible for the management of a hospital ward. The ward manager may be a non-nurse administrator with management training or the position can be (or be combined with) a nursing post.

Back  -    New Search

warfarin (wor-fer-in) n.

an anticoagulant used mainly in the treatment of coronary or venous thrombosis to reduce the risk of embolism. It is given by mouth or injection. Trade name: Marevan .

Back  -    New Search

wart (wort) n.

a benign growth on the skin caused by infection with human papillomavirus. Treatment of warts is with over-the-counter remedies, such as lactic and salicylic acids, but cryotherapy with liquid nitrogen is probably more effective. common w. a firm horny papule found mainly on the backs of the hands. Most will clear spontaneously within two years. genital w. a wart that is frequently associated with other genital infections; affected woman have an increased risk of developing cervical cancer. plane w. a flat skin-coloured wart usually found on the face; it may be present in very large numbers. plantar w. (verruca) a wart occurring on the sole of the foot. Plantar warts are often tender.

Back  -    New Search

Warthin's tumour (adenolymphoma) (wor-thinz) n.

a tumour of the parotid salivary glands, containing epithelial and lymphoid tissues with cystic spaces. [A. S. Warthin (1866–1931), US pathologist]

Back  -    New Search

Wassermann reaction (wass-er-mn) n.

formerly, the most commonly used test for the diagnosis of syphilis. A sample of the patient's blood is examined for the presence of antibodies to the organism Treponema pallidum. [A. P. von Wassermann (1866–1925), German bacteriologist]

Back  -    New Search

water bed (waw-ter) n.

a bed with a flexible water-containing mattress. The surface of the bed adapts itself to the patient's posture, which leads to greater comfort and fewer bedsores.

Back  -    New Search

waterbrash (waw-ter-brash) n.

a sudden filling of the mouth with dilute saliva. This often accompanies dyspepsia, particularly if there is nausea.

Back  -    New Search

water-hammer pulse n.

see CORRIGAN'S PULSE.

Back  -    New Search

Waterhouse-Friderichsen syndrome (waw-ter-howss frid-er-ik-sn) n.

fever, cyanosis, and bleeding into the skin resulting from haemorrhage of both adrenal glands, caused by septicaemia resulting from bacterial meningitis. [R. Waterhouse (1873–1958), British physician; C. Friderichsen (20th century), Danish physician]

Back  -    New Search

Waterston's operation (waw-ter-stnz) n.

the operation of joining the right pulmonary artery to the ascending aorta, performed to relieve tetralogy of Fallot. [D. Waterston (1910– ), British surgeon]

Back  -    New Search

watt (wot) n.

the SI unit of power, equal to 1 joule per second. Symbol: W.

Back  -    New Search

weal (weel) n.

a transient swelling, confined to a small area of the skin, that is characteristic of urticaria and occurs following dermographism.

Back  -    New Search

Weber-Christian disease (web-er kris-chn) n.

a form of panniculitis in which there is fever and enlargement of the liver and spleen. [F. P. Weber (1863–1962), British physician; H. A. Christian (1876–1951), US physician]

Back  -    New Search

Weber's test (vay-berz) n.

a hearing test in which a vibrating tuning fork is placed at the midpoint of the forehead. If one ear is affected by conductive deafness the sound appears louder in the affected ear. [F. E. Weber (1832–91), German otologist]

Back  -    New Search

web space (web spays) n.

the soft tissue between the bases of the fingers and toes.

Back  -    New Search

Wechsler scales (weks-ler) pl. n.

standardized scales for the measurement of intelligence quotient (IQ) in adults and children. They are administered by a chartered psychologist. See INTELLIGENCE TEST. [D. Wechsler (1896–1981), US psychologist]

Back  -    New Search

Wegener's granulomatosis (vay-g-nerz) n.

an autoimmune disease predominantly affecting the nasal passages, lungs, and kidneys, characterized by granuloma formation in addition to arteritis. It is usually fatal but can be controlled (sometimes for years) with steroids, cyclophosphamide, and azathioprine. [F. Wegener (1907–90), German pathologist]

Back  -    New Search

Weil-Felix reaction (vyl fay-liks) n.

a diagnostic test for typhus. A sample of the patient's serum is tested for the presence of antibodies against the organism Proteus vulgaris. [E. Weil (1880–1922), German physician; A. Felix (1887–1956), Czech bacteriologist]

Back  -    New Search

Weil's disease (vylz) n.

see LEPTOSPIROSIS. [A. Weil (1848–1916), German physician]

Back  -    New Search

Welch's bacillus (welch-z) n.

see CLOSTRIDIUM. [W. H. Welch (1850–1934), US pathologist]

Back  -    New Search

wen (wen) n.

see SEBACEOUS CYST.

Back  -    New Search

Werdnig-Hoffmann disease (verd-nig hof-man) n.

a hereditary disorder that is a severe form of spinal muscular atrophy affecting infants. It causes a symmetrical muscle weakness that starts proximally and eventually affects respiratory and facial muscles. Children usually die by the age of 20 months. [G. Werdnig (1844–1919), Austrian neurologist; J. Hoffmann (1857–1919), German neurologist]

Back  -    New Search

Werner's syndrome (vair-nerz) n.

a rare genetic disorder resulting in premature ageing that starts at adolescence. Growth may be retarded and affected individuals may suffer from a thin skin, arterial disease, leg ulcers, and diabetes. [C. W. O. Werner (1879–1936), German physician]

Back  -    New Search

Wernicke's encephalopathy (ver-nik-z) n.

mental confusion or delirium occurring in combination with paralysis of the eye muscles, nystagmus, and an unsteady gait. It is caused by a deficiency of vitamin B_1 and is most commonly seen in alcoholics and in patients with persistent vomiting. [K. Wernicke (1848–1905), German neurologist]

Back  -    New Search

Wertheim's hysterectomy (ver-tymz) n.

a radical operation performed for cervical cancer, involving removal of the entire uterus, the connective tissue and lymph nodes close to it, Fallopian tubes, ovaries, and the upper part of the vagina. [E. Wertheim (1864–1920), Austrian gynaecologist]

Back  -    New Search

Wharton's duct (wor-t'nz) n.

the secretory duct of the submandibular salivary gland. [T. Wharton (1614–73), English physician]

Back  -    New Search

Wharton's jelly n.

the mesoderm tissue of the umbilical cord, which becomes converted to a loose jelly-like mesenchyme surrounding the umbilical blood vessels.

Back  -    New Search

Wheelhouse's operation (weel-howss-z) n.

an operation to relieve urethral stricture in which the incision is made through the perineum. [G. Wheelhouse (1826–1909), British surgeon].

Back  -    New Search

wheeze (weez) n.

an abnormal high-pitched (sibilant) or low-pitched sound that is heard mainly during expiration. Wheezes occur as a result of narrowing of the airways, such as results from bronchospasm or increased secretion and retention of sputum; they are commonly heard in patients with asthma or chronic bronchitis. Compare STRIDOR.

Back  -    New Search

whiplash injury (wip-lash) n.

damage to the ligaments, vertebrae, or spinal cord caused by sudden jerking back of the head and neck, often in occupants of a car hit from behind. It causes pain and stiffness in the neck.

Back  -    New Search

Whipple's disease (wip-lz) n.

a rare disease, occurring only in males, in which there is malabsorption, usually accompanied by skin pigmentation and arthritis. [G. H. Whipple (1878–1976), US pathologist]

Back  -    New Search

Whipple's operation n.

see PANCREATECTOMY. [A. O. Whipple (1881–1963), US surgeon]

Back  -    New Search

Whipple's triad n.

a combination of three clinical features that indicate the presence of an insulinoma:
(1) attacks of fainting, dizziness, and sweating on fasting;
(2) severe hypoglycaemia present during the attacks;
(3) relief from the attacks achieved by administering glucose.

[A. O. Whipple ]

Back  -    New Search

whipworm (wip-werm) n.

a small parasitic whiplike nematode worm, Trichuris trichiura (Trichocephalus dispar), that lives in the large intestine. Human infection (see TRICHURIASIS) results from the consumption of water or food contaminated with faecal material.

Back  -    New Search

white blood cell (wyt) n.

see LEUCOCYTE.

Back  -    New Search

white finger n.

the appearance of a finger resulting from spasm of the vessels of the finger. It occurs in Raynaud's disease but can also be attributed to the long-term use of percussion implements.

Back  -    New Search

white leg n.

inflammation of the femoral vein of the leg, with secondary thrombosis: the leg becomes pale, swollen, tense, and painful. It commonly accompanied puerperal fever (now rare) in women after childbirth. Medical name: phlegmasia alba dolens .

Back  -    New Search

white matter n.

nerve tissue of the central nervous system that is paler in colour than the associated grey matter because it contains more nerve fibres and thus larger amounts of myelin.

Back  -    New Search

white noise instrument n.

a device, resembling a small hearing aid, that produces sounds of many frequencies at equal intensities and is used in the treatment of tinnitus. It was formerly known as a tinnitus masker .

Back  -    New Search

Whitfield's ointment (wit-feeldz) n.

an ointment containing benzoic and salicylic acids, used to treat fungal infections of the skin. [A. Whitfield (1868–1947), British dermatologist]

Back  -    New Search

whitlow (wit-loh) n.

see PARONYCHIA.

Back  -    New Search

WHO n.

see WORLD HEALTH ORGANIZATION.

Back  -    New Search

whoop (hoop) n.

see WHOOPING COUGH.

Back  -    New Search

whooping cough (hoop-ing) n.

an acute infectious disease, primarily affecting infants, due to infection of the respiratory tract by the bacterium Bordetella pertussis. It is characterized by an increasingly severe cough that is accompanied by a noisy involuntary drawing in of the breath (whoop ). The child can become exhausted and may stop breathing. The most common complication is pneumonia. Immunization, usually given in the form of the DPT vaccine, offers protection; an attack usually confers life-long immunity. Medical name: pertussis .

Back  -    New Search

Widal reaction (vi-dahl) n.

an agglutination test for the presence of antibodies against the Salmonella organisms that cause typhoid fever. [G. F. I. Widal (1862–1929), French physician]

Back  -    New Search

Wilms' tumour (vilmz) n.

see NEPHROBLASTOMA. [M. Wilms (1867–1918), German surgeon]

Back  -    New Search

Wilson's disease (wil-snz) n.

an inborn defect of copper metabolism in which there is a deficiency of caeruloplasmin (which normally forms a nontoxic complex with copper). The free copper may be deposited in the liver, causing jaundice and cirrhosis, or in the brain, causing mental retardation and symptoms resembling parkinsonism. Medical name: hepatolenticular degeneration . [S. A. K. Wilson (1878–1936), British neurologist]

Back  -    New Search

windpipe (wind-pyp) n.

see TRACHEA.

Back  -    New Search

wisdom tooth (wiz-dm) n.

the third molar tooth on each side of either jaw, which erupts normally around the age of 20.

Back  -    New Search

witch hazel (hamamelis) (wich hay-zl) n.

a preparation made from the leaves and bark of the tree Hamamelis virginiana. It is used as an astringent, especially for the treatment of sprains and bruises.

Back  -    New Search

withdrawal (with-draw-l) n.

1 (in psychology) the removal of one's interest from one's surroundings.

2 see COITUS (INTERRUPTUS).
Top

Back  -    New Search

withdrawal symptoms pl. n.

see DEPENDENCE.

Back  -    New Search

Wolffian body (vol-fi-n) n.

see MESONEPHROS. [K. F. Wolff (1733–94), German anatomist]

Back  -    New Search

Wolffian duct n.

the mesonephric duct (see MESONEPHROS).

Back  -    New Search

Wolff-Parkinson-White syndrome (wuulf par-kin-sn wyt) n.

a congenital abnormality of heart rhythm caused by the presence of an accessory conduction pathway between the atria and ventricles (see ATRIOVENTRICULAR BUNDLE). It results in premature excitation of one ventricle and is characterized by an abnormal wave (delta wave) at the start of the QRS complex on the electrocardiogram. [L. Wolff (1898–1972, US cardiologist; Sir J. Parkinson (1885–1976), British physician; P. D. White (1886–1973), US cardiologist]

Back  -    New Search

womb (woom) n.

see UTERUS.

Back  -    New Search

Wood's glass (wuudz) n.

a nickel-oxide filter that holds back all but a few rays projected from an ultraviolet light source. These rays (W. light ) cause fluorescence in hair and skin affected by some fungal and bacterial infections and are therefore useful in diagnosis. [R. W. Wood (1868–1955), US physician]

Back  -    New Search

woolsorter's disease (wuul-sor-terz) n.

see ANTHRAX.

Back  -    New Search

word blindness (werd) n.

see ALEXIA.

Back  -    New Search

World Health Organization (WHO) (werld) n.

an international organization in which health issues are discussed and policies evolved mainly through working groups, including acknowledged authorities, and published reports. WHO handles information on internationally notifiable diseases and publishes the International Classification of Diseases.

Back  -    New Search

worm (werm) n.

any of various soft-bodied legless animals, including flatworms, nematode worms, earthworms, and leeches.

Back  -    New Search

wound (woond) n.

a break in the structure of an organ or tissue caused by an external agent; for example, a bruise, cut, or burn.

Back  -    New Search

wrist (rist) n.

1 the joint between the forearm and hand. It consists of the proximal bones of the carpus, which articulate with the radius and ulna.

2 the whole region of the wrist joint, including the carpus and lower parts of the radius and ulna.
Top

Back  -    New Search

wrist drop n.

paralysis of the muscles that raise the wrist, which is caused by damage to the radial nerve.

Back  -    New Search

wryneck (ry-nek) n.

see TORTICOLLIS.

Back  -    New Search

Wuchereria (voo-ker-eer-i) n.

a genus of white threadlike parasitic worms (see FILARIA) that live in the lymphatic vessels. W. bancrofti the species that causes elephantiasis.

Back  -    New Search

X

xamoterol (za-mot-er-ol) n.

a drug that stimulates beta receptors in the heart (see SYMPATHOMIMETIC) and used in the treatment of long-term mild heart failure. It is administered by mouth. Trade name: Corwin .

Back  -    New Search

xanthaemia (carotenaemia) (zanth-ee-mia) n.

the presence in the blood of the yellow pigment carotene, from excessive intake of carrots, tomatoes, or other vegetables containing the pigment.

Back  -    New Search

xanthelasma (zanth--laz-m) n.

yellow plaques occurring symmetrically around the eyelids.

Back  -    New Search

xanthine (zanth-een) n.

a nitrogenous breakdown product of the purines adenosine and guanine. Xanthine is an intermediate product of the breakdown of nucleic acids to uric acid.

Back  -    New Search

xantho- prefix

denoting yellow colour.

Back  -    New Search

xanthochromia (zanth-oh-kroh-mi) n.

yellow discoloration, such as may affect the skin in jaundice or the cerebrospinal fluid when it contains the breakdown products of haemoglobin from red blood cells that have entered it.

Back  -    New Search

xanthoma (zanth-oh-m) n. (pl. xanthomata)

a yellowish skin lesion associated with any of various disorders of lipid metabolism. Tuberous xanthomata are found on the knees and elbows; tendon xanthomata involve the extensor tendons of the hands and feet and the Achilles tendon. Crops of small yellow. papules at any site are known as eruptive xanthomata , while larger flat lesions are called plane xanthomata .

Back  -    New Search

xanthomatosis (zanth-oh-m-toh-sis) n.

the presence of multiple xanthomata in the skin. See XANTHOMA.

Back  -    New Search

xanthopsia (zanth-op-si) n.

yellow vision: the condition in which all objects appear to have a yellowish tinge. It is sometimes experienced in digitalis poisoning.

Back  -    New Search

X chromosome n.

the sex chromosome present in both sexes. Women have two X chromosomes and men one. Genes for some important genetic disorders, including haemophilia, are carried on the X chromosomes. See SEX-LINKED. Compare Y CHROMOSOME.

Back  -    New Search

xeno- prefix

denoting different; foreign; alien.

Back  -    New Search

xenogeneic (zen-oh-ji-nay-ik) adj.

describing grafted tissue derived from a donor of a different species.

Back  -    New Search

xenograft (zen-oh-grahft) n.

see HETEROGRAFT.

Back  -    New Search

Xenopsylla (zen-op-sil-) n.

a genus of tropical and subtropical fleas. X. cheopis the rat flea, which occasionally attacks man and can transmit plague; it also transmits murine typhus and two tapeworms.

Back  -    New Search

xenotransplantation (zen-oh-trans-plahn-tay-shn) n.

the transplantation of organs from one species into another.

Back  -    New Search

xero- prefix

denoting a dry condition.

Back  -    New Search

xeroderma (zeer-oh-der-m) n.

a mild form of the hereditary disorder ichthyosis, in which the skin develops slight dryness and forms branlike scales. It is common in the elderly. x. pigmentosum a rare genetically determined skin disorder in which there is an inherited defect in DNA repair following damage from ultraviolet radiation. This leads to multiple skin cancers.

Back  -    New Search

xerophthalmia (zeer-off-thal-mi) n.

a progressive nutritional disease of the eye due to deficiency of vitamin A. The cornea and conjunctiva become dry, thickened, and wrinkled. This may progress to keratomalacia and eventual blindness.

Back  -    New Search

xeroradiography (zeer-oh-ray-di-og-rfi) n.

X-ray imaging produced on photoconductive paper.

Back  -    New Search

xerosis (zeer-oh-sis) n.

abnormal dryness of the conjunctiva, the skin, or the mucous membranes. In xerosis of the conjunctiva, the membrane becomes thickened and grey in the area exposed when the eyelids are open.

Back  -    New Search

xerostomia (zeer-oh-stoh-mi) n.

see DRY MOUTH. Compare PTYALISM.

Back  -    New Search

xiphi- (xipho-) prefix

denoting the xiphoid process of the sternum.

Back  -    New Search

xiphisternum (zif-i-ster-nm) n.

see XIPHOID PROCESS.

Back  -    New Search

xiphoid process (xiphoid cartilage) (zif-oid) n.

the lowermost section of the breastbone (see STERNUM): a flat pointed cartilage that gradually ossifies until it is completely replaced by bone, a process not completed until after middle age. It does not articulate with any ribs. Also called: ensiform process or ensiform cartilage , xiphisternum .

Back  -    New Search

X-linked disease (eks-linkt) n.

see SEX-LINKED.

Back  -    New Search

X-linked lymphoproliferative syndrome (XLP syndrome) (lim-foh-pr-lif-er--tiv) n.

a hereditary disorder of the immune system caused by a defective sex-linked gene carried on an X-chromosome. There is uncontrolled proliferation of B-lymphocytes in response to infection by the Epstein-Barr virus, which can lead to fulminating hepatitis or lymphoma.

Back  -    New Search

XLP syndrome n.

see X-LINKED LYMPHOPROLIFERATIVE SYNDROME.

Back  -    New Search

X-rays pl. n.

electromagnetic radiation of extremely short wavelength (beyond the ultraviolet), with great penetrating powers in matter opaque to light. X-rays are used in diagnosis in the techniques of radiography and also in radiotherapy. Great care is needed to avoid unnecessary exposure, because the radiation is harmful. See RADIATION (SICKNESS).

Back  -    New Search

X-ray screening n.

the use of a TV monitor to perform X-ray investigations under direct control by a radiologist or radiographer. It has replaced fluoroscopy using a fluorescent screen (see FLUOROSCOPE).

Back  -    New Search

xylene (dimethylbenzene) (zy-leen) n.

a liquid used for increasing the transparency of tissues prepared for microscopic examination after they have been dehydrated.

Back  -    New Search

xylometazoline (zy-loh-mi-taz-oh-leen) n.

a drug that constricts blood vessels (see VASOCONSTRICTOR). It is applied topically as a nasal decongestant in the relief of the common cold and sinusitis. Trade name: Otrivine .

Back  -    New Search

xylose (zy-lohz) n.

a pentose sugar that is involved in carbohydrate interconversions within cells. It is used as a diagnostic aid for intestinal function.

Back  -    New Search

Y

YAG laser (yag) n.

yttrium-aluminium-garnet laser: see LASER.

Back  -    New Search

yawning (yawn-ing) n.

a reflex action in which the mouth is opened wide and air is drawn into the lungs then slowly released. It is a result of drowsiness, fatigue, or boredom.

Back  -    New Search

yaws (pian, framboesia) (yawz) n.

a tropical infectious disease caused by the presence of the spirochaete Treponema pertenue in the skin and its underlying tissues. Yaws occurs chiefly in conditions of poor hygiene. It is characterized by small tumours, each covered by a yellow crust of dried serum, on the hands, face, legs, and feet. These tumours may deteriorate into deep ulcers. The disease responds well to treatment with penicillin and other antibiotics.

Back  -    New Search

Y chromosome n.

a sex chromosome present in men but not in women; it is believed to carry the genes for maleness. Compare X CHROMOSOME.

Back  -    New Search

yeast (yeest) n.

any of a group of fungi in which the body consists of individual cells, which may occur singly, in groups of two or three, or in chains. Baker's yeast (Saccharomyces) ferments carbohydrates to produce alcohol and carbon dioxide and is important in brewing and breadmaking. Some yeasts are a commercial source of proteins and of vitamins of the B complex; others (e.g. Candida, Cryptococcus, Pityrosporum) cause disease.

Back  -    New Search

yellow fever (yel-oh) n.

an infectious disease, caused by an arbovirus, occurring in tropical Africa and South America. It is transmitted by mosquitoes, principally Aëdes aegypti. The virus causes degeneration of the tissues of the liver and kidneys. Symptoms include chill, headache, pains in the back and limbs, fever, vomiting, constipation, a reduced flow of urine (which contains high levels of albumin), and jaundice. Yellow fever often proves fatal.

Back  -    New Search

yellow spot n.

see MACULA (LUTEA).

Back  -    New Search

Yersinia (yer-sin-i) n.

a genus of aerobic or facultatively anaerobic Gram-negative bacteria that are parasites of animals and man. Y. pestis the cause of bubonic plague. Y. enterocolitica a cause of intestinal infections.

Back  -    New Search

yohimbine (yoh-him-been) n.

an alkaloid with sympatholytic effects: it lowers blood pressure and controls arousal and anxiety and has been used to treat both physical and psychogenic impotence.

Back  -    New Search

yolk sac (vitelline sac) (yohk) n.

the membranous sac that lies ventral to the embryo. One of the extra-embryonic membranes, it probably assists in transporting nutrients to the early embryo and is one of the first sites where blood cells are formed.

Back  -    New Search

yttrium-90 (it-rim) n.

an artificial radioactive isotope of the element yttrium, used in radiotherapy.

Back  -    New Search

Z

zalcitabine (ddC) (zal-sy-t-been) n.

a drug, similar to didanosine, that is used in attempts to prolong the lives of AIDS patients. It is administered by mouth.

Back  -    New Search

Zantac (zan-tak) n.

see RANITIDINE.

Back  -    New Search

zein (zee-in) n.

a protein found in maize.

Back  -    New Search

zidovudine (AZT) (zy-dov-yoo-deen) n.

an antiviral drug used in the treatment of AIDS and AIDS-related complex. The drug slows the growth of HIV infection in the body, but is not curative. It is administered by mouth and intravenously; the most common side-effects are nausea, headache, and insomnia, and it may damage the blood-forming tissues of the bone marrow. Trade name: Retrovir .

Back  -    New Search

zinc (zink) n.

a trace element that is a cofactor of many enzymes. Deficiency is rare with a balanced diet but may occur in alcoholics and those with kidney disease; symptoms include lesions of the skin, oesophagus, and cornea and (in children) retarded growth. Symbol: Zn.

Back  -    New Search

zinc oxide n.

a mild astringent used in various skin conditions, usually mixed with other substances. It is applied as a cream, ointment, dusting powder, or as a paste.

Back  -    New Search

zinc sulphate n.

a preparation that is used in the treatment of proven zinc deficiency. It is administered by mouth. Trade names: Solvazinc , Z Span Spansule .

Back  -    New Search

zinc undecenoate (zinc undecylenate) n.

an antifungal agent with uses similar to those of undecenoic acid.

Back  -    New Search

Zollinger-Ellison syndrome (zol-inj-er el-i-sn) n.

a rare disorder in which there is excessive secretion of gastric juice due to high levels of circulating gastrin, which is produced by a pancreatic tumour (see GASTRINOMA) or an enlarged pancreas. The high levels of stomach acid cause diarrhoea and peptic ulcers. [R. M. Zollinger (1903– ) and E. H. Ellison (1918–70), US physicians]

Back  -    New Search

zona pellucida (zoh-n pel-oo-sid-a) n.

the thick membrane that develops around the mammalian oocyte within the ovarian follicle. See OVUM.

Back  -    New Search

zonula (zon-yoo-l) n.

see ZONULE.

Back  -    New Search

zonule (zonula) (zon-yool) n.

(in anatomy) a small band or zone. z. of Zinn (zonula ciliaris) the suspensory ligament of the lens of the eye.
—zonular adj.

Back  -    New Search

zonulolysis (zon-yoo-lol-i-sis) n.

dissolution of the zonule of Zinn, which facilitates removal of the lens in cases of cataract. This technique is not used for modern cataract surgery.

Back  -    New Search

zoo- prefix

denoting animals.

Back  -    New Search

zoonosis (zoh--noh-sis) n.

any infectious disease of animals that can be transmitted to man, such as anthrax or rabies.

Back  -    New Search

zygoma (zy-goh-m) n.

see ZYGOMATIC ARCH, ZYGOMATIC BONE.

Back  -    New Search

zygomatic arch (zygoma) (zy-goh-mat-ik) n.

the horizontal arch of bone on either side of the face, just below the eyes, formed by connected processes of the zygomatic and temporal bones. See SKULL.

Back  -    New Search

zygomatic bone (zygoma, malar bone) n.

either of a pair of bones that form the prominent part of the cheeks and contribute to the orbits. See SKULL.

Back  -    New Search

zygote (zy-goht) n.

the fertilized ovum before cleavage begins.

Back  -    New Search

zym- (zymo-) prefix

denoting 1 an enzyme.

2 fermentation.
Top

Back  -    New Search

zymogen (zy-moh-jen) n.

see PROENZYME.

Back  -    New Search

zymosis (zy-moh-sis) n.

1 the process of fermentation, brought about by yeast organisms.

2 the changes in the body that occur in certain infectious diseases, once thought to be the result of a process similar to fermentation.
Top

—zymotic (zy-mot-ik) adj.

Back  -    New Search

zymotic disease n.

an old name for a contagious disease.

Back  -    New Search

OXFORD

UNIVERSITY PRESS
A Dictionary of Nursing

Reproduced by kind permission of Market House Books Ltd. General Editors

Rosalind Fergusson BA

Elizabeth A. Martin MA

Anne Stibbs BA

Contributors and Advisers

Rajesh Aggarwal BM, MRCP, FRCS, FRCOphth

W. Leslie Alexander FRCS, FRCOphth

J. A. D. Anderson MA, MD, FRCP, FFPHM, FFOM, FROGP

J. H. Angel MD, FRCP

Dr Andrea Atherton MA, MSc, MRCP(UK)

John R. Bennett MD, FRCP

Stuart Anthony Bentley MB, BS

Dr J. N. Bowles BSc, MRCP, FRCR

Dr Peter Bradbury FRCP

Bruce M. Bryant MB, ChB, MRCP

Robert E. Coleman

Patrick Collins MD, MRCP

J. A. Cullen BSc, MSc

W. J. Dinning FRCS, MRCP

Ivan T. Draper MB, ChB, FRCPEd

J. C. Gingell MB, BCh, FRCSEd, FRCS

John M. Goldman DM, FRCP, FRCPath

Dr Helen K. Gordon MRCOG, MMFP

W. J. Gordon MD, FRCS(G), FRCOG

Michael Klaber MA, MB, FRCP

Alexander J. Lewis BSc, MB, BS, MRCPsych

D. J. McFerran MA, FRCS

Gordon Macpherson MB, BS

Charles V. Mann MA, MCh, FRCS

J. E. Nicholl MA, FRCS(Orth)

Heather E. Pitt Ford FDS

T. R. Pitt Ford PhD, BDS, FDS

D. L. Phillips FRCR, FRCOG

Helen Phillips MBBS, MRCGP, DCH, DRCOG

Dr John R. Sewell MA, MB, MRCP

Dr Mary Sibellas MD, FFPHM, DTM&H

Dr Tony Smith MA, BM, BCh

Eric Taylor MA, MB, MRCP, MRCPsych

William F. Whimster MRCP, MRCPath

Robert M. Youngson MB, ChB, DRM&H, DO, FRCOpthal

Sources

Tables 1.1 to 1.6: from A. M. Giles and B. D. Ross (1983), Normal or reference values for biochemical data, Oxford Textbook of Medicine (edited by D. J. Weatherall, J. G. G. Ledingham, and D. A. Warrell).

From A. M. Giles and B. D. Ross (1983), Normal or reference values for biochemical data, Oxford Textbook of Medicine.

From A. M. Giles and B. D. Ross (1983), Normal or reference values for biochemical data, Oxford Textbook of Medicine.

Adapted from D. J. Weatherall (1983), Introduction [to disease of the blood], Oxford Textbook of Medicine.

Table 5.1: from W. P. T. James (1983), Obesity, Oxford Textbook of Medicine. Table 5.2: from World Health Organization (1979) Monograph (WHO/FAP/79.1), reproduced in W. P. T. James (1983), Obesity, Oxford Textbook of Medicine.

Tables 6.1, 6.4: from R. Smith and D. H. Williamson (1983), Biochemical background [to nutrition], Oxford Textbook of Medicine. Tables 6.2, 6.3: from R. Smith and W. P. T. James (1983), Introduction [to nutrition], Oxford Textbook of Medicine.

From D. M. Salisbury and N. T. Begg (1996), Immunisation Against Infectious Disease, HMSO.

United Kingdom Central Council for Nursing. Midwifery and Health Visiting (June 1992).

Consultant Editor: Tanya A. McFerran
Over 10,000 entries
Written by nursing and medical specialists, the dictionary provides comprehensive and authoritative coverage of the ever-expanding vocabulary of the nursing professions. In addition to specifically nursing terms, there are many entries in the fields of medicine, surgery, anatomy, physiology, psychiatry, nutrition, and pharmacology (including new drugs recently introduced into clinical practice). Accident and emergency, trauma, public health medicine, and theory and practice of nursing are all covered.
Tanya A. McFerran is Senior Lecturer in Paediatric Nursing at Homerton College School of Health Studies in Cambridge.

ISBN 0198608454

© Market House Books Ltd 1990, 1994, 1998, 2002

Third Edition, 1998

E-book copyright © 2003.