Posterior shoulder dislocation is an uncommon injury, accounting for only 2% of all shoulder dislocations.
These dislocations are frequently misdiagnosed initially because the affected arm is typically held in a position of adduction and internal rotation, mimicking a normal arm position.
Observation:
Key clinical signs include a fixed internal rotation of the arm.
Characteristic scapular movement during attempted upper extremity abduction is also a notable finding.
Findings:
Standard anteroposterior (AP) shoulder radiographs, sufficient for anterior dislocations, often fail to reveal subacromial posterior dislocations.
Diagnostic imaging requires specific views beyond the routine AP film.
Implications:
Accurate diagnosis of posterior shoulder dislocation relies on recognizing subtle clinical signs and utilizing appropriate radiographic techniques.
Recommended imaging includes an anteroposterior view combined with either an axillary lateral or a tangential scapula view for definitive diagnosis.