Introduction
The complexity of the shoulder joint allows it to perform many different motions and activities. Anatomically, the shoulder involves three different bones – the scapula, the clavicle, and the humerus – many fastening ligaments, and approximately 20 different muscles. The principal articulation, the glenohumeral joint, is joined by ligaments and a group of muscles (and their tendon attachments) known as the rotator cuff. Shoulder pain and disability are generally caused by problems with the rotator cuff. Sports injuries, mechanical dysfunctions from muscle imbalances, or wear and tear of the tissues encompassing the joint are often the causes of shoulder problems. Arthritic changes do take place in the shoulder joint, though not as commonly as in the weight-bearing joints of the spine, hips and knees. (more…)