Shoulder instability is a chronic condition that causes frequent dislocations of the shoulder joint. A dislocation occurs when the end of the humerus (the ball portion) partially or completely dislocates from the glenoid (the socket portion) of the shoulder. A partial dislocation is referred to as a subluxation whereas a complete separation is referred to as a dislocation. The common symptoms of shoulder instability include pain with certain movements of the shoulder; popping or grinding sound may be heard or felt, swelling and bruising of the shoulder may be seen immediately following subluxation or dislocation. Visible deformity and loss of function of the shoulder occurs after subluxation or sensation changes such as numbness or even partial paralysis can occur below the dislocation as a result of pressure on nerves and blood vessels.