A shoulder separation involves the acromioclavicular (AC) joint, where the clavicle or “collar bone” articulates with the top of the shoulder (acromion). A shoulder dislocation involves the true ball ...

This condition is caused when the rotator cuff tendons rub the underside of the acromion bone. Chronic rubbing can lead to a weakening and even tearing of the rotator cuff. Symptoms include pain, ...