Dislocations of the shoulder occur when the bones on opposite sides of a joint do not line up properly. Dislocation of the collarbone joint is a “separated shoulder.” Dislocation of the sternoclavicular joint interrupts the connection between the clavicle and the breastbone (sternum). Dislocation of the ball and socket joint of the shoulder can be toward the front (anterior) or the back (posterior) of the shoulder. Symptoms include pain, deformity, inability to move the arm, and sensation of a dead arm.
Arthritis 
