SCORPION STINGS
SEBACEOUS GLANDS
Scoliosis usually starts in childhood or
adolescence and becomes progressively
more marked until growth stops. In many
cases, another part of the spine curves
to compensate, resulting in an S-shaped
spine. The cause of juvenile scoliosis is
unknown. Rarely, scoliosis is due to a
congenital abnormality of the vertebrae.
In some cases,
physiotherapy
may be
sufficient to control scoliosis. Progressive
or severe scoliosis may require immobi-
lization of the spine in a brace, followed
by surgery (
spinal fusion)
to straighten it.
scorpion stings Injection of venom by a
scorpion into a victim using a sting in its
tail. Many species are not dangerous,
but some in North Africa, southern US,
South America, the Caribbean, and India
are highly venomous. Some stings may
cause only mild pain and tingling; but in
more venomous species severe pain,
restlessness, sweating, diarrhoea, and
vomiting can occur. Stings are rarely fatal
in adults but require prompt attention. If
pain is the only symptom,
analgesics
and a cold compress may be enough. In
severe cases,
antivenom
may be needed.
scotoma An area of abnormal vision
within the
visual field
.
screening The testing of apparently
healthy people with the aim of detect-
ing disease at an early, treatable stage.
(See also
cancer screening.)
scrofula
Tuberculosis
of the lymph nodes
in the neck, often those just beneath the
angle of the jaw. Scrofula is rare in deve-
loped countries. Antituberculous drugs
clear up the condition in most cases.
scrotum The pouch that hangs behind
the penis and contains the
testes
. It con-
sists of an outer layer of thin, wrinkled
skin over a layer of muscular tissue. Swel-
ling of the scrotum may be due to an
inguinal hernia
, swollen testis,
hydrocele
,
or fluid accumulation due to
heart failure
.
scuba-diving medicine A medical spe-
ciality concerned with the physiological
hazards of diving with self-contained
underwater breathing apparatus. Most
hazards stem from the pressure increase
with depth. Conditions treated include
burst lung and
decompression sickness
.
scurvy A disease, now rare in developed
countries, caused by inadequate
vitamin
C
intake. Scurvy disturbs the production
of
collagen
, a protein in
connective tissue
,
causing weakness of small blood vessels
and poor wound healing. Haemorrhages
may occur anywhere in the body, includ-
ing the brain. In the skin, haemorrhages
result in bruising. Bleeding into the
gums and loosening of teeth are com-
mon. Bleeding into muscles and joints
causes pain. Scurvy is treated with large
doses of vitamin C. Bleeding stops in 24
hours, healing resumes, and muscle
and bone pain quickly disappear.
sealants, dental Plastic coatings that
are applied to the chewing surfaces of
the back
teeth
to help prevent decay.
seasickness A type of
motion sickness
.
seasonal affective disorder syndrome
A form of
depression
in which mood
changes occur with the seasons. Sufferers
tend to become depressed in winter and
feel better in spring. Exposure to bright
light for 2-4 hours each morning seems
to prevent occurrence in some people.
sebaceous cyst A harmless smooth nod-
ule under the skin, most commonly on
the scalp, face, ear, and genitals. The
cyst contains a yellow, cheesy material
and may become very large and infected
by bacteria, making it painful. Large or
infected cysts can be surgically removed.
sebaceous glands Glands in the
skin
that secrete a lubricating substance called
sebum
. Sebaceous glands either open
SEBACEO US GLANDS
Hair
Skin
surface
Arrector pili
muscle
Sebum
Sebaceous
gland
Hair
follicle
Fat
S
501
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