producing the pigment
sunlight, adverse effects of;
superego The part of the personality,
as described in
that is responsible for maintaining a
person's standards of behaviour. Popu-
superego arises as a result of a child
incorporating the moral views of those
in authority (usually parents).
superficial Situated near the surface.
superinfection A second
occurs during the course of an existing
infection. The term usually refers to an
infection by a microorganism that is
resistant to drugs being used against
the original infection.
superiority complex An individual's
exaggerated and unrealistic belief that
he or she is better than other people. In
, a superi-
ority complex is considered to be a
compensation for unconscious feelings
of inadequacy or low self-esteem.
supernumerary A term meaning more
than the normal number.
supernumerary teeth One or more
in excess of the usual number.
These teeth are usually extracted.
supination The act of turning the body
to a supine position (lying on the back
with the face upward) or of turning the
hand to a palm forward position. The
opposite of supination is
suppository A solid medical prepara-
tion, of cone or bullet shape, designed
to be placed in the rectum to dissolve.
Suppositories are used to treat rectal
. They may also be used to soft-
en faeces and stimulate defaecation. In
addition, suppositories may be used to
administer drugs into the general circu-
lation, via blood vessels in the rectum, if
vomiting is likely to prevent absorption
after oral administration or if the drug
would cause irritation of the stomach.
suppuration The formation or discharge
suprarenal glands Another name for
supraspinatus syndrome See
supraventricular tachycardia An ab-
normally fast but regular heart-rate that
occurs in episodes lasting for several
hours or days. Supraventricular tachy-
cardia occurs when abnormal electrical
impulses that arise in the atria of the
take control of the heartbeat from
. Symptoms include
palpitations, breathlessness, chest pain,
or fainting (see
Diagnosis is by an
An attack can
sometimes be terminated by
or by drinking cold water.
Recurrent attacks are treated with
Rarely, the condition
may require application of an electric
shock to the heart (see
surfactant A substance, such as a soap
or emulsifier, that reduces surface ten-
sion. Pulmonary surfactant is secreted by
the alveoli in the lungs, preventing them
from collapsing during exhalation, and
is absent in babies born significantly
breathing difficulties, and the infant
and the admin-
istration of an artificial surfactant.
surfer's nodules Multiple bony out-
growths on the foot bones and on the
bony prominence just below the knee.
surgery The treatment of disease, injury,
or other disorders by direct physical inter-
vention, or those aspects of medicine that
deal with the study, diagnosis, and man-
agement of disorders treated in this way.
surgical spirit A liquid preparation,
consisting mainly of ethyl alcohol, that
has a soothing and hardening effect
when applied to the skin. It may be
used before injections as an
surrogacy The agreement by a woman
to become pregnant and give birth to a
child with the understanding that she
will surrender the child after birth to the
contractual parents. Surrogacy may be
in vitro fertilization.
susceptibility A total or partial vulner-
ability to an infection or disorder.
suture A type of
found only be-
tween the bones of the skull, in which the
adjacent bones are mobile during birth
but then become so closely and firmly
joined by a layer of connective tissue that
movement between them is impossible.
The term suture is also used to refer
to a surgical stitch (see