volume is reduced, blood vessels are
abnormally widened, the heart’s action is
weak, blood flow is obstructed, or there
is a combination of these factors. Caus-
es include severe bleeding or burns,
persistent vomitingor diarrhoea, myo-
cardial infarction, pulmonary embolism,
peritonitis, and some types of poisoning.
Symptoms of shock include rapid,
shallow breathing; cold, clammy skin;
rapid, weak pulse; dizziness; weakness;
and fainting. Untreated, shock can lead
to collapse, coma, and death.
Emergency treatment is required. This
involves an intravenous infusionof fluid,
a blood transfusion, oxygen therapy,
and, if necessary, morphineor similar
powerful analgesics. Further treatment
depends on the underlying cause. (See
also anaphylactic shock; septic shock;
shock, electric; toxic shock syndrome.)
shock, electricThe sensation caused by
an electric current passing through the
body, and its effects. A current of suffi-
cient size and duration can cause loss of
consciousness, cardiac arrest, respiratory
arrest, burns, and tissue damage. (See
also electrical injury.)
shock therapySee ECT.
shortsightednessSee myopia.
short sight, operations forSee LASIK;
photorefractive keratectomy; keratotomy,
radial.
short statureA height significantly be-
low the normal range for a person’s age.
Short stature in children is often due to
hereditary factors or slow bone growth.
In most cases, growth eventually speeds
up, resulting in normal adult height. Less
commonly, it is due to a specific disorder
such as bone disease (as in untreated
ricketsor achondroplasia) or certain hor-
monal disorders such as growth hormone
deficiency and hypothyroidism. Emotional
deprivation, chronic malnutrition and
malabsorptioncan alsolimit growth. Cer-
tain chromosomal disorders cause short
stature; stunting occurs in Down’s syn-
drome, and the pubertal growth spurt is
absent in Turner’s syndrome. Other
causes of restricted growth in children
include prolonged use of corticosteroids
and anticancerdrugs. Severe untreated
respiratory disease or congenital heart
disease can also cause short stature.An affected child’s growth rate is moni-
tored by regular measurement of height.
X-raysand blood testsmay help identify
an underlying cause, which will then be
treated. Growth hormone is given for hor-
monedeficiency, and also to treat short
stature due to disorders such as Turner’s
syndrome. (See also growth, childhood.)
shoulderThe area of the body where the
arm attaches to the trunk.Three bones
meet here: the scapula, clavicle, and
humerus. The ball-and-socket joint at the
shoulder has a wide range of movement.
Common injuries include dislocation
(see shoulder, dislocation of) and frac-
tures of the clavicle or upper humerus.
The shoulder may be affected by any
jointdisorder, which in severe cases may
lead to frozenshoulder. Inflammation of
a tendon or a bursa around a shoulder
joint can cause painful arc syndrome.
shoulderbladeThe common name for
the scapula.
shoulder, dislocation ofDisplacement
of the head of the humerusout of the
shoulder joint. The main symptom is
pain in the shoulder and upper arm, made
worse bymovement. A forward disloca-
tion often produces obvious deformity;
a backward dislocation usually does not.
Diagnosis is by X-rays. The head of
the humerus is repositioned in the joint
socket. The shoulder is then immobilized
in a sling for about 3 weeks.
Complications of shoulder dislocation
include damage to nerves, causing tem-
porary weakness and numbness in the
shoulder; damage to an artery in the
upper arm, causing pain and discolor-
ation of the arm and hand; and damage
to muscles that support the shoulder.
shoulder–hand syndromePain and
stiffness affecting one shoulder and the
hand on the same side; the hand may
also become hot, sweaty, and swollen.
Arm muscles may waste through lack of
use (see Sudeck’s atrophy). The cause of
shoulder–hand syndrome is unknown,
but it may occur as a complication of
myocardial infarction, stroke, herpes
zoster, or shoulder injury. Recovery usu-
ally occurs in about 2 years. This period
may be shortened by physiotherapyand
corticosteroid drugs. In rare cases, a cer-
vical sympathectomyis performed.SHOCK, ELECTRIC SHOULDER–HAND SYNDROMES