Althoughmost people think of the shoulder as a single joint, there are really two joints in the area of the shoulder. One is located where the collarbone (clavicle) meets the tip of the shoulder bone (acromion). This is called the acromioclavicular or AC joint. The junction of the upper arm bone (humerus) with the shoulder blade (scapula) is called the glenohumeral joint. There are a variety of conditions that can affect the shoulder, at either joint---more than 4 million people in the U.S. seek medical care each year for shoulder problems. For specific shoulder conditions and ways in which your physician may treat them, see the listings below.
