Webster's New World Medical Dictionary

roseola
See 
measles.
rotator cuff
A group of four tendons that stabi-
lize the shoulder joint. Each of these tendons
attaches to a muscle that moves the shoulder in a
specific direction. The four muscles whose tendons
form the rotator cuff are the subscapularis muscle,
which moves the arm by turning it inward (internal
rotation); the supraspinatus muscle, which is
responsible for elevating the arm and moving it
away from the body; the infraspinatus muscle,
which assists the lifting of the arm during outward
turning (external rotation) of the arm; and the teres
minor muscle, which also helps in the outward
turning (external rotation) of the arm. Damage to
the rotator cuff is one of the most common causes
of shoulder pain.
rotator cuff disease
Damage to the rotator cuff
that can be due to trauma, as from falling and injur-
ing the shoulder; overuse in sports, particularly
those that involve repetitive overhead motions;
inflammation, as from tendonitis, bursitis, or arthri-
tis of the shoulder; or degeneration, as from aging.
The main symptom of rotator cuff disease is shoul-
der pain of gradual or sudden onset, typically
located to the front and side of the shoulder and
increasing when the shoulder is moved away from
the body. A person with torn rotator cuff tendons
may not be able to hold the arm up because of pain.
With very severe tears, the arm falls because of
weakness; this is called the positive drop sign.
Diagnosis is made via observation and can be con-
firmed with X-rays showing bony injuries; an arthro-
gram in which contrast dye is injected into the
shoulder joint to detect leakage out of the injured
rotator cuff; or a magnetic resonance imaging
(MRI) scan, which can provide more information
than either an X-ray or an arthrogram. Treatment
depends on severity. Mild rotator cuff disease is
treated with application of ice, rest, and use of anti-
inflammatory medications, such as ibuprofen. A
patient with persistent pain and motion limitation
may benefit from a cortisone injection in the rotator
cuff and from doing exercises that are specifically
designed to strengthen the rotator cuff. More severe
rotator cuff disease may require arthroscopic or
open surgical repair. Without treatment, including
exercise, the outlook is not very good. Scarring
around the shoulder (adhesive capsulitis) can lead
to marked limitation of range of shoulder motion, a
condition called a frozen shoulder. Some patients
never recover full use of the shoulder joint.
rotavirus
A virus that is a leading cause of severe
diarrhea and dehydration in young children.
Abbreviated RV. Almost everyone catches RV before
entering school, but, with rehydration and good
nutrition, nearly all recover fully. Aside from caus-
ing acute infantile gastroenteritis and diarrhea in
young children, RV is typically accompanied by low-
grade fever. Immunization of infants with a vaccine
against RV was halted in 1999 because of reports of
deaths due to bowel obstruction (from intussuscep-
tion of the bowel) following vaccination, but a
newer vaccine was made available in 2006.