Webster's New World Medical Dictionary

sixth cranial nerve
See 
abducens nerve.
sixth disease
See 
measles.
Sjogren’s syndrome
An autoimmune disease
that classically combines dry eyes, dry mouth, and
another disease of the connective tissues, commonly
rheumatoid arthritis, but sometimes lupus, sclero-
derma, polymyositis, or another autoimmune con-
dition. Sjogren’s syndrome is an inflammatory
disease of glands and other tissues of the body.
Inflammation of the glands that produce tears
(lacrimal glands) leads to decreased tears and dry
eyes. Inflammation of the glands that produce saliva
in the mouth (salivary glands, including the parotid
glands) leads to dry mouth. Sjogren’s syndrome can
consequently be complicated by infections of the
eyes, breathing passages, and mouth. About 90 per-
cent of Sjogren’s syndrome patients are female, usu-
ally middle aged or older. Diagnostic clues include
the presence of antibodies that are directed against
a variety of body tissues (autoantibodies). Diagnosis
can be made via biopsy of an affected gland.
Treatment is directed toward the particular areas of
the body involved and to complications, such as
infection. Also known as keratoconjunctivitis sicca
and sicca syndrome.
skeletal
Pertaining to the skeleton, the bones of
the body that collectively provide the frame for the
body.
skeletal dysplasia
One of a large contingent
of genetic diseases in which the bony skeleton
forms abnormally during fetal development.
Achondroplasia is one form of skeletal dysplasia.
skeletal muscle
Along with smooth and cardiac
muscle, one of the types of muscle tissue in the
body. Skeletal muscle represents the majority of
muscle tissue. It is the type of muscle that powers
movement of the skeleton, as in walking and lifting.
skeleton
The framework of the body, which is
composed of 206 bones. See also 
bones of the arm,
wrist, and hand; bones of the head; bones of the
leg, ankle, and foot; bones of the trunk.
skin
The body’s outer covering, which protects
against heat and light, injury, and infection. Skin
regulates body temperature and stores water, fat,
and vitamin D. The skin, which weighs about 6
pounds, is the body’s largest organ. It is made up of
two main layers: the epidermis and the dermis. The
outer layer of the skin (epidermis) is mostly made
up of flat, scale-like cells called squamous cells.
Under the squamous cells are round cells called
basal cells. The deepest part of the epidermis also
contains melanocytes, cells that produce melanin,
which gives the skin its color. The inner layer of skin
(dermis) contains blood and lymph vessels, hair
follicles, and glands that produce sweat, which
helps regulate body temperature, and sebum, an
oily substance that helps keep the skin from drying
out. Sweat and sebum reach the skin’s surface
through tiny openings called pores.