The shoulder joint is the most mobile joint in the body. Shoulder problems often limit this movement and can be very disabling. Patients often complain of pain. Most cases of shoulder pain only last for a short time, settling with simple treatments. Usually pain from the shoulder is felt on the front and side of the shoulder and may spread down the arm to the elbow. Not all pains felt in the shoulder are caused by problems in the shoulder joint. Pain felt in the upper shoulder and over the shoulder blade may be due to a neck problem, especially if there is tingling or pins and needles below the elbow.

Patients may complain of weakness or stiffness when moving the shoulder. They may also complain that the shoulder comes out of place ( instability).

The shoulder joint is a complex structure. Movements occur between the head of the humerus and the shoulder blade. Movements also occur between the shoulder blade and the chest wall. Movements are also allowed between the shoulder blade and the end of the collar bone.

Shoulder motion is controlled by a group of 4 small muscles called the rotator cuff. The 4 muscles are called the subscapularis, supraspinatus, infraspinatus and teres minor. The tendons of these muscles can become inflamed and sometimes rupture (rotator cuff tendonitis/rotator cuff tear). The rotator cuff is also important in keeping the shoulder in joint. The joint capsule and ligaments are also important in keeping the joint in place( instability). Instability can sometimes be associated with tears of the labrum, which is a ring of cartilage surrounding the shoulder joint socket.

The shoulder may become stiff and painful for a number of reasons. The capsule may become inflamed and contracted leading to a condition called adhesive capsulitis. The shoulder can also become painfully stiff with arthritis, and this can require joint replacement.