Abstract
1. Six cases of posterior dislocation of the shoulder are described.
2. In four cases the diagnosis was made on clinical grounds.
3. The important clinical signs are the adducted and medially rotated position of the arm, a hard mass posteriorly below the acromion representing the displaced humeral head, and limitation of movement, especially abduction and lateral rotation.
4. In two cases the dislocation was not recognised at the first examination. This confirms the statement of previous authors that posterior dislocation is easily missed.
5. The value of the vertical projection in the radiography of suspected posterior dislocation is emphasised.
6. Reduction was accomplished without difficulty in five cases and the subsequent progress of these was uneventful. In the remaining case reduction was difficult and unstable, and the final recovery incomplete. It is considered that this patient would have been better treated by early open reduction.
