Shoulder dislocation or subluxation is an unstable condition of the shoulder joint that gives a feeling of 'giving way' or that the shoulder has suddenly lost its stability.
Shoulder joint dislocation or subluxation is more often caused by trauma of the shoulder joint but it may also occur due to gradual weakening of the ligaments and cartilage that supports the shoulder. It results in the forceful removal of the ball (head of humerus bone) of the joint from its socket (glenoid fossa of scapula).
Shoulder joint dislocation or subluxation is characterized by swelling, numbness, weakness and bruising of the joint area. It may also cause pain and weakness that interfere with activities like lifting arm, changing clothes, moving arm etc.