Woman With Shoulder Pain: Posterior Shoulder Dislocation Diagnosed With Point-of-Care Ultrasound

Posterior shoulder dislocations are relatively rare. When used by emergency medicine physicians, point-of-care ultrasound (POCUS) demonstrates higher sensitivity and specificity for diagnosing shoulder dislocation as compared to two-view plain films. A 49-year-old woman presented to the emergency department (ED) with left shoulder pain following a mechanical fall. Physical examination was remarkable for a gross shoulder deformity and tenderness over the left proximal humerus. POCUS of the left shoulder using a curvilinear probe and a posterior approach was performed and demonstrated posterior displacement of the humeral head relative to the glenoid. Anteroposterior and oblique shoulder X-rays were read as unremarkable by the radiologist; a computed tomography of the shoulder confirmed a posterior shoulder dislocation. Given its efficacy and efficiency as compared to X-ray radiography, POCUS should be strongly considered in the diagnosis and management of posterior shoulder dislocations in the ED setting.