Rotator Cuff Disorders
Rotator cuff disease is a common disorder and results in significant pain and dysfunction in the shoulder. Four muscles envelop and attach to the wing bone or scapula and each blends into a tendon, which travels out over the ball or humeral head to anchor to the upper arm bone or humerus. The four tendons blend together around the ball and form a “cuff” or covering over the humeral head. The muscles and rotator cuff or sheet of tendon tissue serve to stabilize the ball in the socket and rotate the arm. The rotator cuff travels out beneath the roof of the shoulder (acromion). With frequent or heavy use of the shoulder, the rotator cuff may become worn or “threadbare” and develop a partial-thickness or eventually a full-thickness tear or hole. Tears typically grow larger and the rotator cuff muscles become weaker over time. With age and use of the shoulder, bone spurs may develop on the roof of the shoulder, impinge on the tendon tissue below and contribute to rotator cuff damage. Pain, popping, snapping, and weakness may accompany reaching, pulling, or lifting activities when rotator cuff inflammation or a tear is present. Pain may be vague in location, but is often present over the side of the upper arm. Night pain is a common complaint. Tenderness, restricted motion, and rotator cuff weakness are often present. X-rays may reveal bone spurs on the roof of the shoulder that decrease the space between the ball and the roof of the shoulder. An MRI is the most accurate imaging study to evaluate the integrity of the rotator cuff. The extent, location, and size of the tear can be estimated along with the extent of muscle atrophy or shrinkage due to disuse.