Voluntary glenohumeral dislocation.

Voluntary dislocation of the shoulder is a rare condition with radiographic findings similar to traumatic dislocation. Although these dislocations may be anterior, the majority are posterior. Three cases of spontaneous dislocation are described. While two of these cases had previous trauma to the joint, it is possible that there is no causal relationship. Voluntary dislocations are usually elicited in abduction and extension; frontal and axillary views are most helpful in demonstrating glenohumeral subluxations.