Webster's New World Medical Dictionary

muscle, subscapularis
A muscle that moves the
arm by turning it inward (internal rotation). The
tendon of the subscapularis muscle is one of four
tendons that stabilize the shoulder joint and consti-
tute the rotator cuff.
muscle, supraspinatus
A muscle that is respon-
sible for elevating the arm and moving it away from
the body. The tendon of the supraspinatus muscle is
one of four tendons that stabilize the shoulder joint
and constitute the rotator cuff.
muscle, teres minor
A muscle that assists in the
lifting of the arm during outward turning (external
rotation) of the arm. The tendon of the teres minor
muscle is one of four tendons that stabilize the
shoulder joint and constitute the rotator cuff.
muscular
Having to do with muscles or endowed
with above-average muscle development. For exam-
ple, the muscular system is all the muscles of the
body, collectively.
muscular atrophy, post-polio
Muscle wasting
that occurs after the initial acute polio illness.
muscular dystrophy
One of a group of genetic
diseases characterized by progressive weakness and
degeneration of the skeletal or voluntary muscles
that control movement. Abbreviated MD. The mus-
cles of the heart and some other involuntary mus-
cles are also affected in some forms of MD, and a
few forms involve other organs as well. The major
forms of MD include Duchenne MD, Becker MD,
limb-girdle MD, facioscapulohumeral MD, congen-
ital MD, oculopharyngeal MD, distal MD, Emery-
Dreifuss MD, and myotonic dystrophy. MD can
affect people of all ages. Although some forms first
become apparent in infancy or childhood, others
may not appear until middle age or later. Duchenne
MD is the most common kind of MD that affects
children. Myotonic dystrophy is the most common
kind of MD in adults. There is no specific treatment
for any of the forms of MD. Physical therapy to pre-
vent contractures (a condition in which shortened
muscles around joints cause abnormal and some-
times painful positioning of the joints), use of
orthoses (orthopedic appliances used for support),
and corrective orthopedic surgery may be needed to
improve the quality of life in some cases. The prog-
nosis with MD depends on the type of MD. Some
cases may be mild and very slowly progressive, giv-
ing the patient a normal life-span, and other cases
may have more marked progression of muscle
weakness, functional disability, and loss of ambula-
tion. Life expectancy depends on the degree of pro-
gression and late respiratory deficit. In Duchenne
MD, death usually occurs in the late teens to early
20s. See also 
myotonic dystrophy.