CRACK
CRANIAL NERVES
crack
A popular term for a form of
cocaine.
cradle
cap
A condition common in
babies in which thick, yellow scales oc-
cur in patches over the scalp. It is a form
of
seborrhoeic dermatitis,
which may
also occur on the face, neck, behind the
ears, and in the nappy area.
Cradle cap is harmless as long as the
skin does not become infected. The
condition can be treated by daily use of
a simple shampoo. Alternatively, warm
olive oil or arachis oil may be rubbed
into the baby's scalp and left on
overnight in order to loosen and soften
the scales, which can be washed off the
following day. A mild ointment that
contains an
antibiotic drug
and a
corti-
costeroid drug
may be prescribed if the
skin becomes inflamed.
cramp
A painful spasm in a
muscle
caused by excessive and prolonged con-
traction of the muscle fibres. Cramps
often occur as a result of increased
muscular activity, which causes a build-
up of
lactic acid
and other chemicals in
the muscles, and small areas of muscle-
fibre damage. Repetitive movements,
such as writing (see
cramp, writer's
)
or
sitting or lying in an awkward position
may also cause cramp. Cramp may fol-
low profuse sweating because loss of
sodium salts disrupts muscle cell activi-
ty. Massaging or stretching the muscles
involved may bring relief. A drug con-
taining
calcium
or
quinine
may be given
for recurrent night cramps.
Recurrent, sudden pain in a muscle
that is not associated with hardness of
the muscle may be caused by
peripheral
vascular disease
. In this case, the condi-
tion should be investigated and treated
by a doctor.
cramp, writer's
Painful spasm in the
muscles of the hand caused by repeti-
tive movements, which makes writing or
typing impossible.
cranial nerves
Twelve pairs of
nerves
that emerge directly from the underside
of the
brain.
Each of the nerves has a
number as well as a name. The numbers
indicate the sequence in which the
nerves emerge from the brain.
The main function of some cranial
nerves is to deliver sensory information
from the ears, nose, and eyes to the brain.
These are the
vestibulocochlear nerve
(hearing and balance),
olfactory nerve
(smell), and
optic nerve
(vision). Other
cranial nerves carry impulses that move
muscles of the head and neck area. These
are the
oculomotor
,
trochlear
, and
abdu-
cent nerves
(movements of the eye),
spinal accessory nerve
(head and shoul-
der movements), and
hypoglossal nerve
(tongue movements).
Some cranial nerves have both senso-
ry and motor functions. These are the
facial nerve
(facial expressions, taste,
and the secretion of saliva and tears)
trigeminal nerve
(facial sensation and
jaw movements) and
glossopharyngeal
nerve
(taste and swallowing
move-
ments). The
vagus nerve
has branches to
all the main digestive organs, the heart,
and the lungs, and is a major compo-
nent of the
parasympathetic nervous
system
, which is concerned with main-
taining the body's automatic functions.
All but 2 of the cranial nerve pairs con-
nect with nuclei in the
brainstem
(the
olfactory and optic nerves link directly
with parts of the cerebrum). The nerves
emerge through openings in the
cranium;
many then soon divide into branches.
CRANIAL NERVES
Olfactory
Optic
Oculomotor (3),
150
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