Anatomy and Physiology of the Shoulder Joint

As medical director of The Center for Regenerative Medicine, Dr. Alimorad Farshchian treats many injuries and diseases of the shoulder. Dr. Alimorad Farshchian focuses on using cell therapy to treat the cartilage and other connective tissues.

A complex ball-and socket joint, the shoulder actually incorporates the movements of two interrelated joint structures. The first, the glenohumeral joint, functions where the humerus, or upper arm bone, meets the glenoid fossa of the scapula. This shallow joint depends on the rotator cuff muscles to support function and guard against dislocation. A ring of cartilage increases the joint’s flexibility, while area muscles, cartilage, and ligaments strengthen the joint itself.

The shoulder also receives much of its flexibility from the acromioclavicular (AC) joint, which is located where the clavicle’s lateral end meets a bony projection of the scapula. This projection, known as the acromion, connects with the clavicle to make a gliding joint that improves overall shoulder flexibility. The complexity of the shoulder as a whole makes it the most flexible joint in the human body, although the many delicate structures involved also make it vulnerable to dislocation. This frequently results from violent motions of the arm and can lead to surgery or permanent damage.