to heal, or that would leave tethering or
unsightly scars. A skin graft is often
used in the treatment of burns or some-
times for nonhealing ulcers. A piece of
healthy skin is detached from one part
of the body and transferred to the
affected area. New skin cells grow from
the graft and cover the damaged area.
removed and made into a mesh by cut-
ting. The mesh is stretched to fit the
recipient site; new skin cells grow to fill
the spaces in the mesh. In a pinch graft,
multiple small areas of skin are pinched
up and removed from the donor site.
Placed on the recipient site, they gradu-
ally expand to form a new sheet of
healthy skin. (See also
MESHED SKIN GRAFT
PINCH SKIN GRAFT
skin patch See
chemical A cosmetic
operation in which the outer layers of
the skin are peeled away by the applica-
tion of a caustic paste in order to remove
freckles, acne scars, delicate wrinkles, or
other skin blemishes.
skin tag A harmless, small, brown or
flesh-coloured flap of skin that may
appear spontaneously or as a result of
poor healing of a wound.
skin tests Procedures for determining the
body's reaction to various substances by
injecting a small quantity of the sub-
stance under the skin or by applying it
to the skin (usually on patches). Patch
tests are used in the diagnosis of contact
. They can also be used
to test immunity to certain infectious
diseases (such as in the
skin tumours A growth on or in the
that may be cancerous (see
are common types of
noncancerous tumour; other types inc-
skull The bony skeleton of the head,
which rests on the 1st cervical vertebra.
The skull protects the brain, houses the
special sense organs, provides points of
attachment for muscles, and forms part
of the respiratory and digestive tracts .
The 8 bones of the cranium encase the
brain. The skull's facial skeleton includes
the nasal and cheek bones, maxilla, and
mandible. All except the mandible are
fixed together by immovable joints.
skull, fracture of A break in 1 or more of
bones caused by a
In most skull fractures, the broken bones
are not displaced and there are no com-
plications. Severe injury may result in
bone fragments rupturing blood vessels
, or, more rarely, tearing
the meninges, leading to brain damage.
A fracture without complications usually
heals by itself; damage to brain struc-
tures often requires neurosurgery.
skull X-ray A technique for providing
images of the
. X-rays of the skull
are usually taken after a
look for a fracture or foreign body, or to
evaluate disorders that affect the skull.
slapped cheek syndrome An alterna-
tive name for
, an infection
in children caused by parvovirus in
which the cheeks become reddened.
SLE The abbreviation for the disorder
sleep The natural state of lowered con-
sciousness and reduced
There are 2 types of sleep: REM (rapid
eye movement) and NREM (nonrapid eye
movement) sleep, which alternate in
cycles. NREM sleep consists of 4 stages