With thanks to Prathiba.

Your patient is a 18 yo man who presents with left shoulder pain after falling off his skateboard directly onto the shoulder. When you examine him, he seems particularly tender over the medial clavicle. This is his CXR.

Posterior sternoclavicular dislocation

– Infrequent but significant injury – Sternoclavicular dislocations = 1% of all dislocations
– Anterior : posterior – 9:1
– Mechanism: direct force to the shoulder
– MVAs
– Contact sports
– Direct blow to the shoulder or medial clavicle

– 3 grades
Grade I – mild sprain – tenderness over SCJ only, no radiological changes
Grade II – associated subluxation of the joint (ant or post) + rupture of sternoclavicular ligament
Grade III – complete rupture of sternoclavicular and costoclavicular ligaments + dislocation

Posterior sternoclavicular dislocations can be associated with life-threatening injuries in the superior mediastinum (trachea / vascular injuries – jugular / innominate veins or carotid arteries / brachial plexus / recurrent laryngeal nerve) – always look for them clinically ( hoarseness, dysphagia, dyspnoea, neurological deficits in the upper limbs, cyanosis or venous congestion) and have very low threshold to image (CT).