Dictionary of Medical Terms 4th Ed

oesophageal /i sɒfə d i əl/ adjective referring to the oesophagus (NOTE: The US spelling

is esophageal.)

oesophageal hiatus /i sɒfə d i əl ha e təs/ noun the opening in the diaphragm through which the oesophagus passes oesophageal varices /i sɒfə d i əl v r si z/ plural noun varicose veins in the oesophagus

oesophagectomy /i sɒfə d ektəmi/ noun a surgical operation to remove part of the oesophagus (NOTE: The plural is oesophagectomies.)

oesophagi /i sɒfə&i/ plural of oesophagus

oesophagitis /i sɒfə d a t s/ noun inflammation of the oesophagus, caused by acid juices from the stomach or by infection oesophago- /i sɒfə&əυ/ prefix oesophagus

(NOTE: The US spelling is esophago-.) oesophagocele /i sɒfə&əυsi l/ noun a condition in which the mucous membrane lining the oesophagus protrudes through the wall

oesophagogastroduodenoscopy /sɒfə&əυ & strəυ dju əυdə nɒskəpi/ noun

a surgical operation in which a tube is put down into the oesophagus so that the doctor can examine it, the stomach and the duodenum. Abbr OGD (NOTE: The plural is oesoph-

agogastroduodenoscopies.)

oesophagojejunostomy / sɒfə&əυdd u nɒstəmi/ noun a surgical operation to

create a junction between the jejunum and the oesophagus after the stomach has been removed (NOTE: The plural is oesophagojejunos-

tomies.)

oesophagoscope /i sɒfə&əυskəυp/ noun a thin tube with a light at the end, which is passed down the oesophagus to examine it oesophagoscopy /i sɒfə &ɒskəpi/ noun an examination of the oesophagus with an oesophagoscope (NOTE: The plural is

oesophagoscopies.)

oesophagostomy /i sɒfə &ɒstəmi/ noun a surgical operation to make an opening in the oesophagus to allow the person to be fed, usually after an operation on the pharynx (NOTE:

The plural is oesophagostomies.) oesophagotomy /i sɒfə &ɒtəmi/ noun a surgical operation to make an opening in the oesophagus to remove something which is blocking it (NOTE: The plural is oesophagoto-

mies.)

oesophagus /i sɒfə&əs/ noun a tube down which food passes from the pharynx to the stomach (NOTE: The plural is oesophagi. The

US spellings are esophagus and esophagi.) oestradiol / i strə da ɒl/ noun a type of oestrogen secreted by an ovarian follicle, which stimulates the development of secondary sexual characteristics in females at puberty (NOTE: A synthetic form of oestradiol is given as treat-

ment for oestrogen deficiency. The US spelling is estradiol.)

oestriol / i striɒl/ noun a placental hormone with oestrogenic properties, found in the urine of pregnant women (NOTE: The US spelling is estriol.)

oestrogen / i strəd ən/ noun any steroid hormone which stimulates the development of secondary sexual characteristics in females at puberty (NOTE: The US spelling is estrogen.)

COMMENT: Synthetic oestrogens form most oral contraceptives, and are also used in the treatment of menstrual and menopausal disorders.

oestrogenic hormone / i strəd en k hɔ məυn/ noun synthetic oestrogen used to treat conditions which develop during menopause (NOTE: The US spelling is estrogenic hormone.)

oestrone / i strəυn/ noun a type of oestrogen produced in the ovaries (NOTE: The US spelling is estrone.)

official /ə f ʃ(ə)l/ adjective 1. accepted or permitted by an authority We need to undertake a review of the official procedures. 2. constituting an authority

official drug /ə f ʃ(ə)l dr"&/ noun any drug listed in the national pharmacopoiea

officially /ə f ʃ(ə)li/ adverb in a way that is approved by an authority officially listed as a dangerous drug

OGD abbr oesophagogastroduodenoscopy

OH nurse /əυ e tʃ n! s/ abbr occupational health nurse

-oid /ɔ d/ suffix like or related to

oil /ɔ l/ noun a liquid which cannot be mixed with water (NOTE: There are three types of oil: fixed vegetable or animal oils, volatile oils and mineral oils.)

oily / ɔ li/ adjective containing or resembling oil

ointment / ɔ ntmənt/ noun a smooth oily medicinal preparation which can be spread on the skin to soothe or to protect

old age /əυld e d / noun a period in a person’s life, usually taken to be after the age of sixty-five

oleaginous / əυli nəs/ adjective same as oily

olecranon /əυ lekrənɒn/, olecranon process /əυ lekrənɒn prəυsəs/ noun a curved

projecting part at the end of the ulna at the elbow, which gives rise to a painful tingling sensation if hit by accident. Also called funny bone

oleic /əυ li k/ adjective referring to oil oleic acid /əυ li k s d/ noun a fatty acid which is present in most oils

oleo- /əυliəυ/ prefix oil

oleum / əυliəm/ noun oil (used in pharmacy)

olfaction /ɒl f kʃən/ noun 1. the sense of smell 2. the way in which a person’s sensory organs detect smells

olfactory /ɒl f kt(ə)ri/ adjective referring to the sense of smell

olfactory area /ɒl f kt(ə)ri eəriə/ noun the part of the brain that registers smell olfactory bulb /ɒl f kt(ə)ri b"lb/ noun the end of the olfactory tract, where the processes of the sensory cells in the nose are linked to the fibres of the olfactory nerve

olfactory cortex /ɒl f kt(ə)ri kɔ teks/ noun the parts of the cerebral cortex which receive information about smell

olfactory nerve /ɒl f kt(ə)ri n! v/ noun the first cranial nerve which controls the sense of smell

olfactory tract /ɒl f kt(ə)ri tr kt/ noun a nerve tract which takes the olfactory nerve from the nose to the brain

olig- /ɒl &/ prefix same as oligo- (used before vowels)

oligaemia / ɒl &i miə/ noun a condition in which a person has too little blood in his or her circulatory system (NOTE: The US spelling is oligemia.)

oligo- /ɒl &əυ/ prefix few or little oligodactylism / ɒl &əυ d kt l z(ə)m/

noun a congenital condition in which a baby is born without some fingers or toes oligodipsia / ɒl &əυ d psiə/ noun a condition in which a person does not want to drink oligodontia / ɒl &əυ dɒnʃə/ noun a state in

which most of the teeth are lacking oligohydramnios / ɒl &əυha dr mniəs/

noun a condition in which the amnion surrounding the fetus contains too little amniotic fluid

oligomenorrhoea / ɒl &əυmenə ri ə/ noun a condition in which a person menstruates infrequently (NOTE: The US spelling is oligomen-

orrhea.)

oligo-ovulation / ɒl &əυ ɒvjυ le ʃ(ə)n/ noun ovulation which does not occur as often as is usual

oligospermia /ɒl &əυ sp! miə/ noun a condition in which there are too few spermatozoa in the semen

oliguria / ɒl &jυəriə/ noun a condition in which a person does not produce enough urine olive / ɒl v/ noun 1. the fruit of a tree, which gives an edible oil 2. a swelling containing grey matter, on the side of the pyramid of the medulla oblongata

-ology /ɒləd i/ suffix area of study

-olol /əlɒl/ suffix beta blocker atenolol propranolol hydrochloride

o.m. adverb (written on a prescription) every morning. Full form omni mane

-oma /əυmə/ suffix tumour

Ombudsman / ɒmbυdzmən/ Health Serv-

ice Commissioner

oment- /əυment/ prefix omentum omenta /əυ mentə/ plural of omentum

omental /əυ ment(ə)l/ adjective referring to

the omentum

omentectomy / əυmen tektəmi/ noun a surgical operation to remove part of the omen-

tum (NOTE: The plural is omentectomies.) omentopexy /əυ mentəpeksi/ noun a surgi-

cal operation to attach the omentum to the abdominal wall (NOTE: The plural is omentopex-

ies.)

omentum /əυ mentəm/ noun a double fold of peritoneum hanging down over the intestines. Also called epiploon (NOTE: The plural is omenta. For other terms referring to the omentum see words beginning with epiplo-.)

COMMENT: The omentum is in two sections: the greater omentum which covers the intestines, and the lesser omentum which hangs between the liver and the stomach and the liver and the duodenum.

omeprazole /əυ meprəzəυl/ noun a drug which reduces the amount of acid released in the stomach, used in the treatment of ulcers

and heartburn

omphal- /ɒmfəl/ prefix same as omphalo-

(used before vowels)

omphali / ɒmfəli/ plural of omphalus omphalitis / ɒmfə la t s/ noun inflammation of the navel

omphalo- /ɒmfələυ/ prefix navel omphalocele / ɒmfələsi l/ noun a hernia in

which part of the intestine protrudes through the abdominal wall near the navel omphalus / ɒmfələs/ noun a scar with a depression in the middle of the abdomen where the umbilical cord was detached after birth. Also called navel, umbilicus (NOTE: The plural is omphali.)

-omycin /əυma s n/ suffix macrolide drug erythromycin

o.n. adverb (written on a prescription) every

night. Full form omni nocte

onanism / əυnən z(ə)m/ noun same as mas-

turbation

Onchocerca / ɒŋkəυ s! kə/ noun a genus of

tropical parasitic threadworms onchocerciasis / ɒŋkəυs! ka əs s/ noun

infestation with Onchocerca in which the larvae can move into the eye, causing river blind-

ness

onco- /ɒŋkəυ/ prefix tumour

oncogene / ɒŋkəd i n/ noun a part of the genetic system which causes malignant tumours to develop

‘…all cancers may be reduced to fundamental mechanisms based on cancer risk genes or oncogenes within ourselves. An oncogene is a gene that encodes a protein that contributes to the malignant phenotype of the cell’ [British Medical Journal]

oncogenesis / ɒŋkə d enəs s/ noun the origin and development of a tumour oncogenic / ɒŋkə d en k/ adjective causing

tumours to develop an oncogenic virus oncologist /ɒŋ kɒləd st/ noun a doctor

who specialises in oncology, especially cancer oncology /ɒŋ kɒləd i/ noun the scientific

study of new growths, especially cancers oncolysis /ɒŋ kɒləs s/ noun the destruction

of a tumour or of tumour cells

oncometer /ɒŋ kɒm tə/ noun 1. an instrument for measuring swelling in an arm or leg using changes in their blood pressure 2. an instrument for measuring the variations in size of the kidney and other organs of the body oncotic /ɒŋ kɒt k/ adjective referring to a tumour

ondansetron /ɒn d ns trɒn/ noun a drug which helps to prevent the production of serotonin, used to control nausea and vomiting caused by drug treatment and radiotherapy for

cancer

onset / ɒnset/ noun the beginning of something The onset of the illness is marked by sudden high temperature.

ontogeny /ɒn tɒd əni/ noun the origin and development of an individual organism onych- /ɒn k/ prefix same as onycho- (used before vowels)

onychauxis / ɒn kɔ ks s/ noun excessive growth of the nails of the fingers or toes onychia /ɒ n kiə/ noun an irregularity of the nails caused by inflammation of the matrix

onycho- /ɒn kəυ/ prefix nails onychogryphosis / ɒn kəυ&r fəυs s/

noun a condition in which the nails are bent or

curved over the ends of the fingers or toes onycholysis / ɒn kɒləs s/ noun a condition

in which a nail becomes separated from its

bed, without falling out

onychomadesis / ɒn kəυmə di s s/ noun a

condition in which the nails fall out onychomycosis / ɒn kəυma kəυs s/ noun

an infection of a nail with a fungus onychosis / ɒn kəυs s/ noun any disease of

the nails (NOTE: The plural is onychoses.) o’nyong-nyong fever / əυ njɒŋ njɒŋ

fi və/ noun an infectious virus disease prevalent in East Africa, spread by mosquitoes. The symptoms are high fever, inflammation of the lymph nodes and excruciating pains in the joints. Also called joint-breaker fever

oo- /əυə/ prefix ovum or embryo

oocyesis / əυəsa i s s/ noun a pregnancy which develops in the ovary (NOTE: The plural

is oocyeses.)

oocyte / əυəsa t/ noun a cell which forms from an oogonium and becomes an ovum by

meiosis

oocyte donation / əυəsa t dəυ ne ʃ(ə)n/ noun the transfer of oocytes from one woman

to another who cannot produce her own, so that she can have a baby. The oocytes are re-

moved in a laparoscopy and fertilised in vitro. oogenesis / əυə d enəs s/ noun the forma-

tion and development of ova

COMMENT: In oogenesis, an oogonium produces an oocyte, which develops through several stages to produce a mature ovum. Polar bodies are also formed which do not develop into ova.

oogenetic / əυəd ə net k/ adjective refer-

ring to oogenesis

oogonium / əυə &əυniəm/ noun a cell produced at the beginning of the development of

an ovum (NOTE: The plural is oogonia.) oophor- /əυəfəυr/ prefix same as oophoro-

(used before vowels)

oophoralgia / əυəfə r ld ə/ noun pain in

the ovaries

oophore / əυəfɔ / noun same as ovary oophorectomy / əυəfə rektəmi/ noun a

surgical operation to remove an ovary. Also called ovariectomy (NOTE: The plural is

oophorectomies.)

oophoritis / əυəfə ra t s/ noun inflammation in an ovary, which can be caused by

mumps. Also called ovaritis oophoro- /əυɒfərəυ/ prefix ovary

oophorocystectomy /əυ ɒfərəυs stektəmi/ noun a surgical operation to re-

move an ovarian cyst (NOTE: The plural is

oophorocystectomies.)

oophorocystosis /əυ ɒfərəυs stəυs s/ noun the development of one or more ovarian

cysts

oophoroma / əυəfə rəυmə/ noun a rare ovarian tumour, occurring in middle age (NOTE:

The plural is oophoromas or oophoromata.) oophoron /əυ ɒfərɒn/ noun same as ovary

(technical) (NOTE: The plural is oophora.) oophoropexy /əυ ɒfərəpeksi/ noun a surgi-

cal operation to attach an ovary (NOTE: The plu-

ral is oophoropexies.)

oophorosalpingectomy /əυ ɒfərə s lp n d ektəmi/ noun a surgical operation to re-

move an ovary and the Fallopian tube attached to it (NOTE: The plural is oophorosalpingectomies.)

ooze /u z/ verb 1. (of pus, blood or other liquid) to flow slowly 2. to leak a substance such as pus or blood (NOTE: oozing – oozed)

op /ɒp/ noun an operation (informal)

OP abbr outpatient

opacification /əυp s f ke ʃ(ə)n/ noun the fact of becoming opaque, as the lens does in a case of cataract

opacity /əυ p s ti/ noun 1. the fact of not allowing light to pass through 2. an area in the eye which is not clear (NOTE: The plural is opacities.)

opaque /əυ pe k/ adjective not allowing light to pass through. Opposite transparent

open / əυpən/ adjective not closed

open-angle glaucoma / əυpən ŋ&(ə)l &lɔ kəυmə/ noun an unusually high pressure

of fluid inside the eyeball caused by a blockage in the channel through which the aqueous humour drains. Also called chronic glaucoma open fracture / əυpən fr ktʃə/ noun same

as compound fracture

open-heart surgery / əυpən hɑ ts! d əri/ noun surgery to repair part of the heart or one of the coronary arteries performed while the heart has been bypassed and the blood is circulated by a pump

opening / əυp(ə)n ŋ/ noun a place where something opens

open visiting / əυpən v z t ŋ/ noun an arrangement in a hospital by which visitors can enter the wards at any time

operable / ɒp(ə)rəb(ə)l/ adjective referring to a condition which can be treated by a surgical operation The cancer is still operable. operant conditioning / ɒpərənt kənd ʃ(ə)n ŋ/ noun a form of learning which takes place when a piece of spontaneous behaviour is either reinforced by a reward or discouraged by punishment

operate / ɒpəre t/ verb 1. to function or work, or to make something function or work 2. to treat a person for a condition by cutting open the body and removing a part which is diseased or repairing a part which is not functioning correctly The patient was operated on yesterday. The surgeons decided to operate as the only way of saving the baby’s life.

(NOTE: operating – operated)

operating department noun a hospital department specialising in surgical operations

operating department assistant / ɒpəre*

t ŋ d pɑ tmənt ə s stənt/ noun a person who works in an operating department. Abbr ODA

ma krəskəυp/ noun a special microscope with two eyepieces and a light, used in very delicate surgery

operating room US same as operating theatre. Abbr OR

operating table / ɒpəre t ŋ te b(ə)l/ noun a special table on which the patient is placed to undergo a surgical operation

operating theatre / ɒpəre t ŋ θ ətə/ noun a special room in a hospital, where surgical operations are carried out (NOTE: The US term is operating room.)

operation / ɒpə re ʃ(ə)n/ noun 1. the way in which something operates 2. a surgical procedure carried out to repair or remove a damaged body part She’s had an operation on her foot. The operation to remove the cataract was successful. A team of surgeons performed the operation. Heart operations are always difficult. (NOTE: A surgeon performs or

carries out an operation on a patient.) 3. the way in which a drug acts

operative / ɒp(ə)rət v/ adjective taking place during a surgical operation. peropera-

tive, postoperative, preoperative

operator / ɒpəre tə/ noun 1. someone whose job is to operate a machine or piece of equip-

ment 2. a surgeon who operates on people operculum /ə p! kjυləm/ noun 1. a part of

the cerebral hemisphere which overlaps the insula 2. a plug of mucus which can block the cervical canal during pregnancy (NOTE: The

plural is opercula or operculums.) ophth- /ɒfθ, ɒpθ/ prefix eye

ophthalm- /ɒfθ lm, ɒpθ lm/ prefix same as

ophthalmo- (used before vowels) ophthalmectomy / ɒfθ l mektəmi/ noun a

surgical operation to remove an eye (NOTE: The plural is ophthalmectomies.)

ophthalmia /ɒf θ lmiə/ noun inflammation

of the eye

ophthalmia neonatorum /ɒf θ lmiə ni əυne tɔ rəm/ noun conjunctivitis of a newborn baby, beginning 21 days after birth, caused by infection in the birth canal ophthalmic /ɒf θ lm k/ adjective referring to the eye

ophthalmic nerve /ɒf θ lm k n! v/ noun a branch of the trigeminal nerve, supplying the eyeball, the upper eyelid, the brow and one

side of the scalp

ophthalmic optician /ɒf θ lm k ɒp t ʃ(ə)n/, ophthalmic practitioner noun same as optician

ophthalmic surgeon /ɒf θ lm k s! d ən/ noun a surgeon who specialises in surgery to treat eye disorders

ophthalmitis / ɒfθ l ma t s/ noun inflam-

mation of the eye

ophthalmo- /ɒfθ lməυ, ɒpθ lməυ/ prefix

eye or eyeball

ophthalmological /ɒf θ lmə lɒd k(ə)l/

adjective referring to ophthalmology ophthalmologist / ɒfθ l mɒləd st/ noun

a doctor who specialises in the study of the eye

and its diseases. Also called eye specialist ophthalmology / ɒfθ l mɒləd i/ noun the

study of the eye and its diseases ophthalmoplegia / ɒfθ lmə pli d ə/ noun

paralysis of the muscles of the eye ophthalmoscope /ɒf θ lməskəυp/ noun

an instrument containing a bright light and small lenses, used by a doctor to examine the

inside of an eye

ophthalmoscopy / ɒfθ l mɒskəpi/ noun an examination of the inside of an eye using an ophthalmoscope (NOTE: The plural is ophthal-

moscopies.)

ophthalmotomy / ɒfθ l mɒtəmi/ noun a surgical operation to make a cut in the eyeball

(NOTE: The plural is ophthalmotomies.)

ophthalmotonometer / ɒfθ lmətə nɒm tə/ noun an instrument which measures

pressure inside the eye

-opia /əυpiə/ suffix eye condition

opiate / əυpiət/ noun a sedative which is prepared from opium, e.g. morphine or codeine opinion /ə p njən/ noun what a person thinks about something What’s the surgeon’s opinion of the case? The doctor asked the consultant for his opinion as to the best method of treatment.

opioid / əυpiɔ d/ adjective based on opium

Codeine is an opioid analgesic.

opistho- /ɒp sθəυ/ prefix backbone opisthotonos / ɒp s θɒtənəs/ noun a spasm

of the body in which the spine is arched back-

wards, occurring, e.g., in people with tetanus opium / əυpiəm/ noun a substance made

from poppies which is used in the preparation

of codeine and heroin

opponens /ə pəυnənz/ noun one of a group of muscles which control the movements of the fingers, especially one which allows the

thumb and little finger to come together

opportunist / ɒpə tju n st/, opportunistic /

ɒpətju n st k/ adjective referring to a parasite or microorganism which takes advantage of the host’s weakened state to cause infection opposition / ɒpə z ʃ(ə)n/ noun 1. hostility towards something 2. a movement of the hand muscles in which the tip of the thumb is made to touch the tip of another finger so as to hold

something

opsonic index /ɒp sɒn k ndeks/ noun a number which gives the strength of a person’s serum reaction to bacteria

opsonin / ɒpsən n/ noun a substance, usually an antibody, in blood which sticks to the surface of bacteria and helps to destroy them optic / ɒpt k/ adjective referring to the eye or to sight

optical / ɒpt k(ə)l/ adjective 1. same as optic

2. relating to the visible light spectrum optical fibre / ɒpt k(ə)l fa bə/ noun an arti-

ficial fibre which can carry light or images optical illusion / ɒpt k(ə)l lu (ə)n/ noun

something which is seen wrongly so that it ap-

pears to be something else

optic chiasma / ɒpt k ka zmə/ noun a structure where some of the optic nerves from each eye partially cross each other in the hypothalamus

optic disc / ɒpt k d sk/ noun the point on the retina where the optic nerve starts. Also called

optic papilla

optic fundus / ɒpt k f"ndəs/ noun the back part of the inside of the eye, opposite the lens optician /ɒp t ʃ(ə)n/ noun a qualified person who specialises in making glasses and in testing eyes and prescribing lenses. Also called ophthalmic optician (NOTE: In US English, an

optician is a technician who makes lenses and fits glasses, but cannot test patient’s eyesight.)

COMMENT: In the UK qualified opticians must be registered by the General Optical Council before they can practise.

optic nerve / ɒpt k n! v/ noun the second cranial nerve which transmits the sensation of sight from the eye to the brain. See illustration

at EYE in Supplement

optic neuritis / ɒpt k njυ ra t s/ noun same

as retrobulbar neuritis

optic papilla / ɒpt k pə p lə/ noun same as

optic disc

optic radiation / ɒpt k re di e ʃ(ə)n/ noun a nerve tract which takes the optic impulses from the optic tract to the visual cortex optics / ɒpt ks/ noun the study of the visible

light spectrum and sight

optic tract / ɒpt k tr kt/ noun a nerve tract which takes the optic nerve from the optic ch-

iasma to the optic radiation opto- /ɒptəυ/ prefix sight

optometer /ɒp tɒm tə/ noun same as refrac-

tometer

optometrist /ɒp tɒmətr st/ noun mainly US a person who specialises in testing eyes and

prescribing lenses

optometry /ɒp tɒmətri/ noun the testing of eyes and prescribing of lenses to correct sight -oquine /əkw n/ suffix antimalarial drug chloroquine

OR abbr US operating room

ora / ɔ rə/ plural noun plural of os noun 2 oral / ɔ rəl/ adjective 1. referring to the mouth 2. referring to medication that is swallowed an oral contraceptive Compare enteral, parenteral

oral cavity / ɔ rəl k v ti/ noun the mouth oral contraceptive / ɔ rəl kɒntrə sept v/

noun a contraceptive pill which is swallowed oral hygiene / ɔ rəl ha d i n/ noun the

practice of keeping the mouth clean by gargling and mouthwashes

orally / ɔ rəli/ adverb by swallowing not to

be taken orally

oral medication / ɔ rəl med ke ʃ(ə)n/ noun medication which is taken by swallowing

oral rehydration solution / ɔ rəl ri ha dre ʃ(ə)n sə lu ʃ(ə)n/ noun a liquid given as

a drink to correct the water, mineral and nutritional deficiencies in a person who is affected by dehydration

oral rehydration therapy / ɔ rəl ri ha dre ʃ(ə)n θerəpi/ noun the administration of

a simple glucose and electrolyte solution to treat acute diarrhoea, particularly in children, which has greatly reduced the number of deaths from dehydration. Abbr ORT

oral thermometer / ɔ rəl θə mɒm tə/ noun a thermometer which is put into the mouth to take someone’s temperature

orbicularis /ɔ b kjυ leər s/ noun a circular

muscle in the face

orbicularis oculi /ɔ b kjυ leər s ɒkjυla /

noun a muscle which opens and closes the eye orbicularis oris /ɔ b kjυ leər s ɔ r s/

noun a muscle which closes the lips tight orbit / ɔ b t/ noun the hollow bony depression in the front of the skull in which each eye and lacrimal gland are situated. Also called eye socket

orbital / ɔ b t(ə)l/ adjective referring to the orbit

orchi- /ɔ k / prefix testis

orchidalgia / ɔ k d ld ə/ noun a neuralgic-

type pain in a testis

orchidectomy / ɔ k dektəmi/ noun a surgical operation to remove a testis (NOTE: The plu-

ral is orchidectomies.)

orchidopexy / ɔ k dəυ peksi/ noun a surgical operation to place an undescended testis in the scrotum. Also called orchiopexy (NOTE:

The plural is orchidopexies.)

orchidotomy / ɔ k dɒtəmi/ noun a surgical operation to make a cut into a testis (NOTE: The

plural is orchidotomies.) orchiepididymitis / ɔ ki ep d d ma t s/

noun a condition in which a testicle and its

epididymis become swollen

orchiopexy / ɔ kiəυ peksi/ noun same as orchidopexy (NOTE: The plural is orchiopexies.) orchis / ɔ k s/ noun a testis

orchitis /ɔ ka t s/ noun inflammation of the testes, characterised by hypertrophy, pain and

a sensation of weight

orderly / ɔ dəli/ noun a person who does general work in a hospital (NOTE: The plural is or-

derlies.)

Orem’s model / ɔ rəmz mɒd(ə)l/ noun a modern model for nursing which focuses on a person’s ability to perform self-care, defined as activities which individuals initiate and perform on their own behalf to maintain life, health and well-being

organ / ɔ &ən/ noun a part of the body which is distinct from other parts and has a particular function, e.g. the liver, an eye or ovaries organic /ɔ & n k/ adjective 1. referring to organs in the body 2. coming from an animal, plant or other organism 3. referring to food which has been cultivated naturally, without certain fertilisers or pesticides

organically /ɔ & n kli/ adverb in a natural

or apparently natural way

organic disease /ɔ & n k d zi z/, organic disorder /ɔ & n k d s ɔ də/ noun a disease or disorder associated with physical changes

in one or more organs of the body organisation / ɔ &əna ze ʃ(ə)n/, organiza-

tion noun 1. a group of people set up for a particular purpose 2. the planning or arranging of something the organisation of the rota 3. the

way in which the component parts of something are arranged

organism / ɔ &ən z(ə)m/ noun any single plant, animal, bacterium, fungus or other liv-

ing thing

organo- /ɔ &ənəυ, ɔ & nəυ/ prefix organ organ of Corti / ɔ &ən əv kɔ ti/ noun a

membrane in the cochlea which takes sounds and converts them into impulses sent to the brain along the auditory nerve. Also called spiral organ [Described 1851. After Marquis Alfonso Corti (1822–88), Italian anatomist and histol-

ogist.]

organotherapy / ɔ &ənəυ θerəpi/ noun the treatment of a disease by using an extract from the organ of an animal, e.g. using liver extract

to treat anaemia

organ transplant / ɔ &ən tr nsplɑ nt/ noun a surgical operation to transplant an organ from one person to another

orgasm / ɔ & z(ə)m/ noun the climax of the sexual act, when a person experiences a mo-

ment of great excitement

oriental sore / ɔ rient(ə)l sɔ / noun a skin disease of tropical countries caused by the parasite Leishmania. leishmaniasis

orifice / ɒr f s/ noun an opening in the body, e.g. the mouth or anus

origin / ɒr d n/ noun 1. the source or beginning of something 2. a place where a muscle is attached, or where the branch of a nerve or blood vessel begins

original /ə r d ən(ə)l/ adjective as before a change was made The surgeon was able to move the organ back to its original position. originate /ə r d ne t/ verb to start in a place, or make something start drugs which originated in the tropics The treatment originated in China. (NOTE: originating – originated)

oris / ɔ r s/ cancrum oris, orbicularis oris ornithine / ɔ n θa n/ noun an amino acid produced by the liver

ornithosis / ɔ n θəυs s/ noun a disease of birds which can be passed to humans as a form of pneumonia

oro- /ɔ rəυ/ prefix mouth

orogenital / ɔ rəυ d en t(ə)l/ adjective re-

lating to both the mouth and the genitals oropharynx / ɔ rəυ f r ŋks/ noun a part of

the pharynx below the soft palate at the back of the mouth (NOTE: The plural is oropharynxes or oropharynges.)

ORT abbr oral rehydration therapy ortho- /ɔ θəυ/ prefix correct or straight

orthodiagraph / ɔ θəυ da ə&rɑ f/ noun an X-ray photograph of an organ taken using only a thin stream of X-rays which allows accurate

measurements of the organ to be made orthodontia / ɔ θə dɒnʃə/ noun US same as

orthodontics

orthodontic / ɔ θəυ dɒnt k/ adjective correcting badly formed or placed teeth He had to undergo a course of orthodontic treatment. orthodontics / ɔ θəυ dɒnt ks/ noun a branch of dentistry which deals with correcting badly placed teeth (NOTE: The US term is orthodontia.)

orthodontist / ɔ θəυ dɒnt st/ noun a dental surgeon who specialises in correcting badly placed teeth

orthopaedic / ɔ θə pi d k/ adjective 1. referring to treatment which corrects badly formed bones or joints 2. referring to or used in ortho-

paedics (NOTE: The US spelling is orthopedic.) orthopaedic collar / ɔ θə pi d k kɒlə/

noun a special strong collar to support the head of a person with neck injuries or a condition such as cervical spondylosis

orthopaedic hospital / ɔ θəpi d k hɒs p t(ə)l/ noun a hospital which specialises in operations to correct badly formed joints or bones

orthopaedics / ɔ θə pi d ks/ noun a branch of surgery dealing with irregularities, diseases and injuries of the locomotor system (NOTE: The US spelling is orthopedics.) orthopaedic surgeon / ɔ θəpi d k s! d ən/ noun a surgeon who specialises in orthopaedics

orthopaedist / ɔ θə pi d st/ noun a surgeon who specialises in orthopaedics (NOTE: The US spelling is orthopedist.)

orthopnoea / ɔ θəp ni ə/ noun a condition in which a person has great difficulty in breathing while lying down. dyspnoea

(NOTE: The US spelling is orthopnea.) orthopnoeic / ɔ θəp ni k/ adjective referring to orthopnoea (NOTE: The US spelling is or-

thopneic.)

orthopsychiatry / ɔ θəυsa ka ətri/ noun the science and treatment of behavioural and personality disorders

orthoptics /ɔ θɒpt ks/ noun the study of methods used to treat squints

orthoptist /ɔ θɒpt st/ noun an eye specialist, working in an eye hospital, who treats squints and other disorders of eye movement orthoptoscope /ɔ θɒptəskəυp/ noun same as amblyoscope

orthosis /ɔ θəυs s/ noun a device which is fitted to the outside of the body to support a weakness or correct a malformation, e.g. a surgical collar or leg brace (NOTE: The plural is orthoses.)

orthostatic / ɔ θə st t k/ adjective referring to the position of the body when standing up straight

orthostatic hypotension / ɔ θəst t k ha pəυ tenʃən/ noun a common condition

where the blood pressure drops when a person stands up suddenly, causing dizziness

orthotics /ɔ θɒt ks/ plural noun the branch of medical engineering which deals with the design and fitting of devices such as braces in the treatment of orthopaedic disorders orthotist / ɔ θət st/ noun a qualified person who fits orthoses

Ortolani’s sign / ɔ tə lɑ niz sa n/, Ortolani manoeuvre / ɔ tə lɑ ni mə nu və/, Ortolani’s test / ɔ tə lɑ niz test/ noun a test for congen-

ital dislocation of the hip in babies aged 6–12, in which the hip makes sharp sounds if the joint is rotated [Described 1937. After Marius Ortolani, Italian orthopaedic surgeon.]

os /ɒs/ noun (technical) 1. a bone (NOTE: The plural is ossa.) 2. the mouth (NOTE: The plural is ora.)

OSA abbr obstructive sleep apnoea oscillation / ɒs le ʃ(ə)n/ noun 1. the action of moving backwards and forwards between two points at a regular speed 2. a single move-

ment between two points

oscilloscope /ɒ s ləskəυp/ noun a device which produces a visual record of an electrical current on a screen using a cathode ray tube. It is used in the testing of electronic equipment and in measuring electrical impulses of the

heart or the brain.

osculum / ɒskjυləm/ noun a small opening or pore (NOTE: The plural is oscula.)

-osis /əυs s/ suffix disease

Osler’s nodes / ɒsləz nəυdz/ plural noun tender swellings at the ends of fingers and toes in people who have subacute bacterial endocarditis [Described 1885. After Sir William Osler (1849–1919), Professor of Medicine in Montreal, Philadelphia, Baltimore and then Oxford.]

osm- /ɒzm/ prefix 1. smell 2. osmosis osmoreceptor / ɒzməυr septə/ noun a cell in the hypothalamus which checks the level of osmotic pressure in the blood by altering the secretion of ADH and regulates the amount of water in the blood

osmosis /ɒz məυs s/ noun the movement of a solvent from one part of the body through a semipermeable membrane to another part where there is a higher concentration of mole-

cules

osmotic pressure /ɒz mɒt k preʃə/ noun the pressure required to stop the flow of a sol-

vent through a membrane ossa / ɒsə/ plural of os noun 1

osseous / ɒsiəs/ adjective referring to or re-

sembling bone

osseous labyrinth / ɒsiəs l bər nθ/ noun same as bony labyrinth

ossicle / ɒs k(ə)l/ noun a small bone

COMMENT: The auditory ossicles pick up the vibrations from the eardrum and transmit them through the oval window to the cochlea in the inner ear. The three bones are articulated together; the stapes is attached to the membrane of the oval window, the malleus to

the eardrum, and the incus lies between the other two.

ossification / ɒs f ke ʃ(ə)n/ noun the formation of bone. Also called osteogenesis ossium / ɒsiəm/ fragilitas ossium

ost- /ɒst/ prefix same as osteo- (used before

vowels)

ostectomy /ɒ stektəmi/ noun a surgical operation in which a bone, or a piece of bone, is removed (NOTE: The plural is ostectomies.) osteitis / ɒsti a t s/ noun inflammation of a bone due to injury or infection

osteitis deformans / ɒsti a t s di fɔ mənz/ noun a disease which gradually softens bones in the spine, legs and skull, so that they become curved. Also called Paget’s dis-

ease

osteitis fibrosis cystica / ɒstia t s fabrəυs s s st kə/ noun a generalised weak-

ness of bones, caused by excessive activity of the thyroid gland and associated with formation of cysts, in which bone tissue is replaced by fibrous tissue. Also called von Recklinghausen’s disease (NOTE: The localised form is

osteitis fibrosis localista.) osteo- /ɒstiəυ/ prefix bone

osteoarthritis / ɒstiəυɑ θra t s/ noun a degenerative disease of middle-aged and elderly people characterised by inflamed joints which become stiff and painful. Also called osteoar-

noun a disease of the bone and cartilage at a joint, particularly the ankles, knees or wrists, associated with carcinoma of the bronchi osteoarthrosis / ɒstiəυɑ θrəυs s/ noun

same as osteoarthritis

osteoarthrotomy / ɒstiəυɑ θrɒtəmi/ noun a surgical operation to remove the articular end of a bone (NOTE: The plural is osteoarthroto-

mies.)

osteoblast / ɒstiəυbl st/ noun a cell in an embryo which forms bone osteochondritis / ɒstiəυkən dra t s/ noun degeneration of the epiphyses

osteochondritis dissecans / ɒstiəυkɒndra t s d sək nz/ noun a painful condition

where pieces of articular cartilage become detached from the joint surface osteochondroma / ɒstiəυkən drəυmə/ noun a tumour containing both bony and cartilaginous cells (NOTE: The plural is osteochon-

dromas or osteochondromata.) osteochondrosis / ɒstiəυkɒn drəυs s/

noun a disorder of cartilage and bone formation which affects the joints in children, causing pain and a limp, probably due to circulation disturbances to that part of the bone

osteoclasia / ɒstiəυ kle ziə/, osteoclasis /

ɒsti ɒkləs s/ noun 1. destruction of bone tissue by osteoclasts 2. a surgical operation to

fracture or refracture bone to correct a deform-

ity

osteoclast / ɒstiəυkl st/ noun 1. a cell which destroys bone 2. a surgical instrument

for breaking bones

osteoclastoma / ɒstiəυkl stəυmə/ noun a usually benign tumour occurring at the ends of long bones (NOTE: The plural is osteoclasto-

mas or osteoclastomata.)

osteocyte / ɒstiəυsa t/ noun a bone cell

osteodystrophia / ɒstiəυd strəυfiə/, osteodystrophy / ɒstiəυ d strəfi/ noun a bone

disease, especially one caused by disorder of

the metabolism

osteogenesis / ɒstiəυ d enəs s/ noun same as ossification

osteogenesis imperfecta / ɒstiəυd enəs s mpə fektə/ noun a congenital

condition in which bones are brittle and break easily due to unusual bone formation. Also

called brittle bone disease

osteogenic / ɒstiəυ d en k/ adjective made

of or originating in bone tissue

osteology / ɒsti ɒləd i/ noun the study of bones and their structure

osteolysis / ɒsti ɒləs s/ noun 1. destruction of bone tissue by osteoclasts 2. loss of bone calcium

osteolytic / ɒstiəυ l t k/ adjective referring to osteolysis

osteoma / ɒsti əυmə/ noun a benign tumour in a bone (NOTE: The plural is osteomas or os-

teomata.)

osteomalacia / ɒstiəυmə le ʃə/ noun a condition in adults in which the bones become soft because of lack of calcium and Vitamin D, or

limited exposure to sunlight

osteomyelitis / ɒstiəυma ə la t s/ noun inflammation of the interior of bone, especially

the marrow spaces

osteon / ɒstiɒn/ noun same as Haversian

system

osteopath / ɒstiəυ p θ/ noun a person who

practises osteopathy

osteopathy / ɒsti ɒpəθi/ noun 1. the treatment of disorders by massage and manipulation of joints 2. any disease of bone (NOTE: The

plural is osteopathies.)

osteopetrosis / ɒstiəυpə trəυs s/ noun a disease of a group in which bones increase in

density. Also called marble bone disease osteophony / ɒsti ɒfəni/ noun the conduc-

tion of sound by bone, as occurs in the ear.

Also called bone conduction

osteophyte / ɒstiəυfa t/ noun a bony

growth

osteoplastic necrotomy / ɒstiəυpl st k nek rɒtəmi/ noun a surgical operation to re-

move a piece of dead bone tissue osteoplasty / ɒstiəυpl sti/ noun plastic

surgery on bones

osteoporosis / ɒstiəυpɔ rəυs s/ noun a condition in which the bones become thin, porous and brittle, due to low levels of oestrogen, lack of calcium and lack of physical exercise. Also called brittle bone disease

COMMENT: Osteoporosis mainly affects postmenopausal women, increasing the risk of fractures. Hormone replacement therapy is the most effective method of preventing osteoporosis though there are other risks to health from long-term use.

osteosarcoma / ɔ stiəυsɑ kəυmə/ noun a malignant tumour of bone cells (NOTE: The plural is osteosarcomas or osteosarcomata.) osteosclerosis / ɒstiəυsklə rəυs s/ noun a condition in which the bony spaces become hardened as a result of persistent inflammation osteotome / ɒstiəυtəυm/ noun a type of chisel used by surgeons to cut bone osteotomy / ɒsti ɒtəmi/ noun a surgical operation to cut a bone, especially to relieve pain in a joint (NOTE: The plural is osteotomies.)

ostia / ɒstiə/ plural of ostium

ostium / ɒstiəm/ noun an opening into a passage (NOTE: The plural is ostia.)

ostomy / ɒstəmi/ noun a colostomy or ileos-

tomy (informal) (NOTE: The plural is ostomies.)

-ostomy /ɒstəmi/ suffix operation to make an opening

OT abbr occupational therapist

ot- /əυt/ prefix same as oto- (used before vowels)

otalgia /əυ t ld ə/ noun same as earache

OTC abbreviation referring to medication which can be bought freely at a chemist’s shop, and does not need a prescription. Full

form over the counter

OTC drug / əυ ti si dr"&/ noun same as over-the-counter drug

otic / əυt k/ adjective referring to the ear otic ganglion / əυt k & ŋ&liən/ noun a ganglion associated with the mandibular nerve where it leaves the skull

otitis /əυ ta t s/ noun inflammation of the ear otitis externa /əυ ta t s k st! nə/ noun inflammation of the external auditory meatus to the eardrum

otitis interna /əυ ta t s n t! nə/ noun inflammation of the inner ear. Also called labyrinthitis

otitis media /əυ ta t s mi diə/ noun an infection of the middle ear, usually accompanied by headaches and fever. Also called middle ear infection, tympanitis

oto- /əυtəυ/ prefix ear

otolaryngologist / əυtəυl r ŋ &ɒləd st/ noun a doctor who specialises in treatment of diseases of the ear and throat otolaryngology / əυtəυl r ŋ &ɒləd i/ noun the study of diseases of the ear and throat

otolith / əυtəl θ/ noun a tiny piece of calcium carbonate attached to the hair cells in the saccule and utricle of the inner ear

otolith organ / əυtəl θ ɔ &ən/ noun one of two pairs of sensory organs in the inner ear, the saccule and the utricle, which pass information to the brain about the position of the head otologist /əυ tɒləd st/ noun a doctor who specialises in the study of the ear

otology /əυ tɒləd i/ noun the scientific study of the ear and its diseases

-otomy /ɒtəmi/ suffix an act of cutting into an organ or part of the body in a surgical operation

otomycosis / əυtəma kəυs s/ noun an infection of the external auditory meatus by a fungus

otoplasty / əυtəpl sti/ noun plastic surgery of the external ear to repair damage or deformity

otorhinolaryngologist / əυtəυ ra nəυl r ŋ &ɒləd st/ noun a doctor who special-

ises in the study of the ear, nose and throat

otorhinolaryngology / əυtəυ ra nəυl r ŋ &ɒləd i/ noun the study of the ear, nose

and throat. Also called ENT

otorrhagia / əυtə re d ə/ noun bleeding from the external ear

otorrhoea / əυtə ri ə/ noun the discharge of pus from the ear (NOTE: The US spelling is otor-

rhea.)

otosclerosis / əυtəυsklə rəυs s/ noun a condition in which the ossicles in the middle ear become thicker and the stapes becomes fixed to the oval window leading to deafness otoscope / əυtəskəυp/ noun same as auri-

scope

otospongiosis / əυtə sp"nd i əυs s/ noun the formation of spongy bone in the labyrinth of the ear which occurs in otosclerosis Otosporin / əυtəspɒr n/ a trade name for ear drops containing hydrocortisone, neomycin and polymyxin

ototoxic / əυtə tɒks k/ adjective referring to a drug or an effect which is damaging to organs or nerves involved in hearing or balance outbreak / aυtbre k/ noun a series of cases of a disease which starts suddenly There was an outbreak of typhoid fever or a typhoid outbreak.

outcome / aυtk"m/ noun 1. what happens as the result of something 2. a measure of the result of an intervention or treatment, e.g. the mortality rate following different methods of surgery medical outcomes

outer / aυtə/ adjective outside or external outer ear / aυtər ə/ noun the part of the ear which is on the outside of the head, together with the passage leading to the eardrum. Also called external ear

outer pleura / aυtə plυərə/ noun same as

parietal pleura

outlet / aυtlet/ noun an opening or channel

through which something can go out

out-of-body experience / aυt əv bɒdi ksp əriəns/ noun an occasion when a person

feels as though they have left their body and, often, travelled along a tunnel towards a bright light (NOTE: It may happen after anaesthesia, perhaps caused by the brain not having enough

oxygen.)

outpatient / aυtpe ʃ(ə)nt/ noun someone who comes to a hospital for treatment but does not stay overnight She goes for treatment as

an outpatient. Abbr OP. Compare inpatient

outpatient department / aυtpe ʃ(ə)nt dpɑ tmənt/, outpatients’ department / aυt pe ʃ(ə)nts d pɑ tmənt/, outpatients’ clinic / aυtpe ʃ(ə)nts kl n k/ noun a department of

a hospital which deals with outpatients outreach / aυtri tʃ/ noun services provided

for patients or the public in general, outside a

hospital or clinic

ova / əυvə/ plural of ovum

oval window / əυv(ə)l w ndəυ/ noun an oval opening between the middle ear and the inner ear. Also called fenestra ovalis. See il-

lustration at EAR in Supplement

ovar- /əυvər/ prefix same as ovari- (used be-

fore vowels)

ovaralgia / əυvə r ld ə/ noun pain in the

ovaries. Also called ovarialgia ovari- /əυvəri/ prefix ovaries

ovarialgia / əυveəri ld ə/ noun same as ovaralgia

ovarian /əυ veəriən/ adjective referring to

the ovaries

ovarian cancer /əυ veəriən k nsə/ noun a malignant tumour of the ovary, which occurs

especially after the menopause

ovarian cycle /əυ veəriən sa k(ə)l/ noun the regular changes in the ovary during a wom-

an’s reproductive life

ovarian cyst /əυ veəriən s st/ noun a cyst

which develops in the ovaries

ovarian follicle /əυ veəriən fɒl k(ə)l/ noun a cell which contains an ovum. Also called

Graafian follicle

ovariectomy / əυvəri ektəmi/ noun same as oophorectomy (NOTE: The plural is ovariecto-

mies.)

ovariocele /əυ veəriəυsi l/ noun a hernia of

an ovary

ovariotomy / əυvəri ɒtəmi/ noun a surgical operation to remove an ovary or a tumour in an ovary (NOTE: The plural is ovariotomies.) ovaritis / əυvə ra t s/ noun same as oophori-

tis

ovary / əυv(ə)ri/ noun one of two organs in a woman which produce ova or egg cells and secrete the female hormone oestrogen. Also

called oophoron. See illustration at UROGENI-

TAL SYSTEM (FEMALE) in Supplement (NOTE: The plural is ovaries. For other terms referring to ovaries, see words beginning with oophor-, oophoro-.)

over- /əυvə/ prefix too much

overbite / əυvəba t/ noun the usual formation of the teeth, in which the top incisors come down over and in front of the bottom incisors when the jaws are closed

overcome / əυvə k"m/ verb 1. to fight something and win 2. to make a person lose consciousness Two people were overcome by smoke in the fire. (NOTE: overcoming – overcame – overcome)

overcompensate / əυvə kɒmpənse t/ verb to try too hard to cover the effects of a condition or quality (NOTE: overompensating – overcompensated)

overcompensation / əυvəkɒmpən se ʃ(ə)n/ noun an attempt by a person to remove the bad effects of a mistake or a fault in their character in which they make too much effort, and so cause some other problem overdo / əυvə du / verb to overdo it or to overdo things to work too hard or to do too much exercise (informal) She overdid it, working until 9 o’clock every evening. He has been overdoing things and has to rest. overdose / əυvədəυs/ noun a dose of a drug which is larger than the recommended or usual dose

overeating / əυvər i t ŋ/ noun eating too much food

overexertion / əυvər & z! ʃ(ə)n/ noun doing too much physical work or taking too much exercise

overflow incontinence / əυvəfləυ n kɒn t nəns/ noun a leakage of urine because the bladder is too full

overgrow / əυvə &rəυ/ verb (of a tissue) to grow over another tissue (NOTE: overgrew – overgrown)

overgrowth / əυvə&rəυθ/ noun a growth of tissue over another tissue

overjet / əυvəd et/ noun a space which separates the top incisors from the bottom incisors when the jaws are closed

overlap / əυvə l p/ verb (of bandages, etc.) to lie partly on top of another (NOTE: overlapping – overlapped)

overprescribe /əυvəpr skra b/ verb to issue too many prescriptions for something

Some doctors seriously overprescribe tranquillisers. (NOTE: overprescribing – overprescribed)

overproduction / əυvəprə d"kʃən/ noun the act of producing too much of something

The condition is caused by overproduction of thyroxine by the thyroid gland.