Since 1980, we have treated twelve patients who had antero-inferior subluxation of humeral head after acute trauma to the shoulder or to the proximal part of the humerus, of both.

the diagnosis of subluxation was based on clinical and radiographic examination. To evaluate the rdiological features, and also to clarify the mechanism as well as the treatment for this subluxation, we have been analysed and the following results were obtained.

1. The careful radiographic interpretation, especially standing neutral shoulder AP and lateral films, was quite important to find the hidden soft tissue injuries which it could be caused the subluxation of humeral head after acute trauma to the shoulder.

2. The incidences of subluxation was 24.5%, 12 cases out of the total 49 cases.

3. The subluxation was frequently frequently developed in adduction type of fracture, avulsion fracture of the greater tuberosity and in women with over the 40 of their ages.

4. Intial subluxation of humeral head after trauma might be caused by the rupture of capsule of rotator cuff, and late subluxation may be developed by the loss of damaged muscle tone or direct muscle damage due to intial or sugical trauma.

5. Except the results of the nerve damage after trauma or surgery, the subluxation could be recovered by average 22 day after the first recognition of subluxation with hte vigorous isometric biceps setting exercise immediately after trauma.

6. Isometric biceps seetting exercise was the most important basic step for the every injuries aroud the shoulder joint.