CRUCIATE LIGAMENT
C
cruciate ligament
One of the two
ligaments
in the knee
that pass over each other to form a
cross. The ligaments form connections
between the
femur
and
tibia
inside the
knee joint and prevent
overbending
and overstraightening at the knee.
crush syndrome
Damage to a large amount of
muscle
(usually as a result of a serious acci-
dent), w hich causes
kidney failure
.
The
damaged muscles release proteins into
the bloodstream, temporarily im pair-
ing kidney function. As a result, some
substances normally
excreted in the
urine build up to toxic levels in the
blood.
If left
untreated,
crush
syn-
drome may be fatal, but
dialysis
allows
the kidneys time to recover.
crutch palsy
Weakness or
paralysis
of muscles in the
wrist, fingers, and thumb in people who
walk with a crutch under the armpit.
Crutch palsy is due to pressure on the
nerves
supplying these muscles. It does
not occur if elbow crutches are used.
crying in infants
A normal response in babies to needs
or
discomforts,
such
as
hunger
or
thirst. Most healthy babies stop crying
when their needs are attended to. In a
few cases, persistent crying may be due
to a physical cause such as intolerance
of cow’s m ilk or an illness (such as an
ear or throat infection, or a viral fever).
cryo-
A prefix meaning “ice cold” . It is used
of medical procedures that involve the
use of freezing or low temperatures.
cryopreservation
The preservation of living cells or tissue
samples by freezing. The technique is
used to store human eggs for
in vitro fer-
tilization
,
sperm for
artificial insemination
,
or
plasma
and blood obtained from
people with rare blood groups.
cryosurgery
The use of temperatures below freezing
to destroy tissue, or the use of cold
during surgical procedures to produce
adhesion
between an instrument and an
area of body tissue.
Cryosurgery
causes
only
minimal
scarring. It is used to treat cancerous
tumours in sites where heavy scarring
can block vital openings, such as in the
cervix,
the liver, and the intestines. It
may be used in eye operations, for
example in
cataract surgery
and treat-
ment for
retinal detachment.
It is also
commonly used for removing
warts,
skin tags,
some
birthmarks,
and some
skin cancers, and to treat
haemorrhoids.
cryotherapy
The use of cold or freezing tempera-
tures or substances in treatment. (See
also
cryosurgery.)
cryptococcosis
A rare infectious disorder caused by
inhaling the fungus C
ryptococcus neofor
-
mans
, w hich is found especially in soil
contaminated with pigeon faeces. The
most serious form that the infection
can take is
meningitis.
Another form of
infection causes growths in the lungs,
resulting in chest pain and a cough, or
on the skin, causing a rash of ulcers.
Most cases of cryptococcosis occur in
people with reduced immunity, such as
those with
AIDS.
Cryptococcal meningitis is diagnosed
from a sample of spinal fluid. A com bi-
nation of the antifungal drugs
ampho-
tericin B
and flucytosine is usually pre-
scribed to
treat the infection.
Most
cases
in w hich
only the
lungs are
infected need no treatment.
cryptophthalmus
A
birth defect
in w hich the opening
between the upper and lower eyelids is
absent. (See also
Fraser’s syndrome.)
cryptorchidism
A
developmental
disorder
of
male
infants
in
w hich
the
testes
fail
to
descend normally into the scrotum (see
testis, undescended).
cryptosporidiosis
A type of diarrhoeal infection caused
by
protozoa,
w hich may be spread from
person to person or be transmitted
from domestic animals to people. The
disease causes watery diarrhoea and
sometimes fever and abdominal pain. It
is most common in children but also
occurs in people with AIDS.
In most cases,
rehydration therapy
is
the only treatment needed. In people
whose
immune system
is
suppressed,
however, the infection may be much
more severe. Such people may need to
be admitted to hospital for treatment
with intravenous fluids and
antidiar-
rhoeal drugs.
CSF
The abbreviation for
cerebrospinal fluid
.
CS spray
A noxious powder, also known as CS
gas or tear gas, that is used in aerosol
form as a means of riot control. CS
spray causes severe irritation of the
eyes, airways, and skin, and sometimes
nausea and vomiting. Its
effects are
short-lived, usually lasting for only a
few minutes.
CT scanning
A diagnostic technique in w hich the
combined use of a computer and a
machine emitting
X-rays
produces cross-
sectional images of the body tissues.
A CT (computed tomography) scan-
ner is a machine that is shaped like a
doughnut
that
rotates
around
the
patient’s body The machine contains
one or more X-ray sources and, on the
opposite side, some X-ray detectors.
Unlike
a
conventional
X-ray
image,
w hich shows only a few levels of tissue
density, the X-ray detector can register
hundreds of levels of density. It sends
this information to a computer, w hich
processes the data and shows the results
as an image on a monitor. CT images
usually show the body as “slices” , in
w hich the different tissues can be seen
in detail. In some machines, this infor-
mation
can
be
used
to
produce
a
three-dimensional
reconstruction
of
the area scanned.
CT scanning has revolutionized the
diagnosis and treatment of
tumours
,
ab-
scesses
,
and haemorrhages in the brain,
as well as
head injuries
and
strokes
.
The
procedure is also used to locate and
show tumours, to investigate a wide
range of diseases, and to aid needle
biopsy
in organs of the trunk.
Newer types of CT scanners use a
spiral technique: the scanner rotates
around the
body as
the
patient
is
moved slowly forwards on a bed, caus-
ing the X-ray beams to follow a spiral
course. Images can be made of hollow
organs such as the colon (a procedure
known as “virtual colonoscopy”). For
some
procedures,
injected
or
swal-
lowed contrast media (chemicals that
are opaque to X-rays) may be used to
make certain tissues more easily visible.
The
images
produced
during
CT
scanning can be stored digitally or on
conventional X-ray film. (For details of
the procedure, see
Performing a CT scan
box, opposite.)
206
previous page 205 BMA A Z Family Medical Encyclopedia   2004 read online next page 207 BMA A Z Family Medical Encyclopedia   2004 read online Home Toggle text on/off