Bma Illustrated Medical Dictionary

cobalaminA cobalt-containing com-

plex molecule, part of vitamin B 12.

cobaltA metallic element and a con-

stituent of vitamin B 12. A radioactive

form of cobalt is used in radiotherapy.

cocaineA drug obtained from the leaves

of the coca plant ERYTHROXYLON COCA,

once used as a local anaesthetic (see

anaesthesia, local) for minor surgical

procedures. Cocaine affects the brain,

producing euphoria and increased ener-

gy. Because of its effects, cocaine is

subject to drug abuse. Continued use

can lead to psychological dependence

(see drug dependence), andpsychosisif

high doses are taken. Regular inhaling

of the drug can damage the lining of the

nose. Overdose can cause seizures and

cardiac arrest. “Crack’’, a purified form of

cocaine, produces a moreintense reac-

tion and has caused deaths due to

adverse effects on the heart.

cocciSpherical bacteria, some of which

are responsible for certain infections in

humans (see staphylococcal infections;

streptococcal infections).

coccydyniaA pain in the region of the

coccyx. Coccydynia may result from a

blow to the base of the spine in a fall,

from prolonged pressure due to poor

posture when sitting, or the use of the

lithotomy position during childbirth.

The pain usually eases in time. Treat-

ment may include heat, injections of a

local anaesthetic, and manipulation.

coccyxA small triangular bone made up

of 4 tiny bones fused together at the base

of the spine. Together with a larger bone

called the sacrum, it forms the back sec-

tion of the pelvis. There is very little

relative movement between the coccyx

and sacrum. Later in life, they common-

ly become fused together.

cochleaThe spiral-shaped organ situat-

ed in the labyrinth of the inner ear that

transforms sound vibrationsinto nerve

impulses for transmission to the brain,

enabling hearing.

cochlear implantA device used to

treat profoundly deaf people who are

not helped by hearing aids. A cochlear

implant consists of tiny electrodes sur-

gically implanted in the cochlea deep in

the inner ear and a receiver that is

embedded in the skull just behind and

above the ear. A microphone, sound

processor, and transmitter are worn

externally. A cochlear implant does not

restore normal hearing, but it enables

patterns of sound to be detected. Com-

bined with lip-reading, it may enable

speech to be understood.

co-codamolA compound analgesic drug

containing paracetamoland codeine.

codeineAn opioid analgesic drugderived

from the opiumpoppy plant. Codeine is

a useful treatment for mild to moderate

pain and may be used in combination

with other opioid analgesics. It is also

used as a cough remedyand as an anti-

diarrhoeal drug. It may cause dizziness

and drowsiness, especially if taken with

alcohol. Taken long-term, codeine may

cause constipation and be habit-forming.

cod-liver oilAn oil obtained from the

liver of fresh cod, which is a valuable

source of vitamin Aand vitamin D.

COBALAMIN COD-LIVER OIL

C

Pubis

Ischium

Coccyx

PELVIS

Pelvic

inlet

Ilium

COCCYX

Pubic

symphysis

Outer

ear

Middle

ear

Inner

ear

Semicircular canal

COCHLEA

LOCATION

INNER EAR

Cochlea

Cochlea