AC

Acromioclavicular

The acromioclavicular (AC) joint is a small joint located at the top of the shoulder, where the clavicle (collarbone) meets the acromion, a bony projection of the scapula (shoulder blade). It provides stability and facilitates the movement of the shoulder, particularly during overhead or arm-raising motions. The AC joint is supported by ligaments and is susceptible to injury, especially in athletes, with AC joint separation (a “separated shoulder”) being a frequent result of trauma or direct impact to the shoulder.