The scapulohumeral line revisited.

Routine observation of the scapulohumeral line in the true anteroposterior radiographic view of the shoulder will allow a higher level of confidence in ruling out posterior dislocation of the glenohumeral joint. It will also facilitate evaluation of the relationship between the proximal humerus and the scapula (especially the acromion and the glenoid fossa) in (1) abnormal conditions of the subacromial space; (2) fractures and dislocations of the proximal humerus; and (3) proximal humerus prosthesis insertion and assessment.