The rotator cuff is a group of tough, flexible fibers (tendons) and muscles in the
shoulder . Rotator cuff disorders occur when tissues in
the shoulder get irritated or damaged. Rotator cuff disorders include:
- Inflammation of
the tendons (tendinitis) or of a bursa (bursitis). In
the shoulder, a bursa is a small, fluid-filled sac that serves as a cushion
between the tendons and the bones.
- Impingement, in which a tendon
is squeezed and rubs against bone.
- Calcium buildup in the tendons,
which causes a painful condition called calcific tendinitis.
Partial or complete tears of the rotator cuff tendons .
The shoulder is a joint with three
main bones: the upper arm bone (humerus), the collarbone (clavicle), and the
shoulder blade (scapula). The bones are held together by muscles, tendons, and
ligaments. The rotator cuff keeps the upper arm bone
in the shoulder socket and lets you raise and twist your arm.
shoulder is a ball-and-socket
joint. The ball at the top of the upper arm bone fits
into the socket of the shoulder blade. This socket is shallow, which lets you
move your arm in a wide range of motion. But it also means that the muscles and
tendons of the rotator cuff have to work hard to hold the bones in place. As a
result, they are easy to injure and are prone to wear and tear.
Most rotator cuff disorders are caused by a combination of:
- Normal wear and tear. Using your shoulder for
many years slowly damages the rotator cuff. As you age, everyday activities can
lead to changes in the rotator cuff, such as thinning and fraying of the
tendons and reduced blood supply.
- Overuse. Activities in which you
use your arms above your head a lot—such as tennis, swimming, or house
painting—can lead to rotator cuff problems. Even normal motions made often over
a long period can stress or injure the rotator cuff.
It takes great force to tear a healthy rotator cuff
tendon. This can happen during sports, an accident, or a severe fall. But even
a simple movement like lifting a suitcase can cause a rotator cuff tear in an
older adult or someone whose shoulder is already damaged.