STENOSIS
STETHOSCOPE
stenosis Narrowing of a duct, canal,
passage, or tubular organ.
stent A rigid tube that is surgically inser-
ted to open up or keep open any body
canal that may have become narrowed or
closed up due to disease. Stents are used
to open narrowed coronary arteries in
heart disease. They are also used to
relieve blockages caused by a tumour, for
example in the
oesophagus
or
pancreas.
sterculia A bulk-forming
laxative
used to
treat constipation. It is especially useful
when stools are small and hard. Stercu-
lia should only be used if fibre intake
cannot be increased; adequate fluid
intake must be maintained to avoid in-
testinal obstruction. Side effects may
include flatulence, bloating, and gastro-
intestinal obstruction or impaction.
stereotaxic surgery Brain operations
carried out by inserting delicate instru-
ments through a surgically created hole
in the skull and guiding them, with the
aid of
CT scanning
, to a specific area.
Stereotaxic procedures can be used to
treat
pituitary tumours
; for a brain
biopsy
;
or to destroy small areas of the brain to
treat disabling neurological disorders.
sterility The state either of being germ-
free or of permanent
infertility
.
sterilization The complete destruction
or removal of living organisms, usually to
prevent spread of infection; any proce-
dure that renders a person infertile (see
sterilization, female; vasectomy).
sterilization, female A usually perma-
nent method of
contraception
in which
the fallopian tubes are sealed in order
to prevent sperm reaching the ova.
Female
sterilization
is
usually per-
formed by
laparoscopy,
which involves
2
small incisions in the abdomen. Some-
times it is done by minilaparotomy, in
which a single incision is made in the
pubic area. The fallopian tubes are
sealed using clips or by cutting and
tying. The operations have a low failure
rate. Fertility can sometimes be restored
after sterilization using
microsurgery
.
sterilization, male See
vasectomy
.
sternum The long, narrow, flat plate of
bone at the front of the chest. The ster-
num has 3 parts: an upper, triangular
portion (manubrium); a long middle part
(body); and, at the lower end, a small,
leaf-shaped projection (xiphoid process).
The upper manubrium articulates with
the inner ends of the
clavicles
. The
ribs
are attached to the sides of the manubri-
um and body by cartilage. Between the
manubrium and body is a
symphysis
joint, allowing slight movement when
the ribs rise and fall during breathing.
Great force is required to fracture the
sternum. The main danger of such an
injury is the possibility that the broken
bone may be driven inwards, damaging
the heart, which lies behind the sternum.
steroid drugs A group of drugs includ-
ing
corticosteroid drugs
and anabolic
steroids (see
steroids, anabolic
).
steroids, anabolic Drugs that have an
anabolic (protein-building) effect similar
to
testosterone
. Anabolic steroids build
tissue, promote muscle recovery after
an injury, and strengthen bones. They
are used to treat
some
types
of
anaemia
.
Anabolic
steroids are often
abused by athletes.
Possible
adverse
effects of the drugs
include acne,
oede-
ma
, damage to the
liver and adrenal
glands,
infertility,
impotence in men,
and
virilization
in
women.
stethoscope An
instrument that is
used for listening
SITES OF INCISION
LAPAROSCOPIC CLIP STERILIZATION
S
525
previous page 523 BMA Illustrated Medical Dictionary read online next page 525 BMA Illustrated Medical Dictionary read online Home Toggle text on/off