The posterior sternoclavicular ligament reinforces the posterior capsule of the sternoclavicular joint, running from the posterior aspect of the sternal end of the clavicle to the posterior surface of the manubrium. It is the strongest component of the SC joint capsule and provides the primary restraint against posterior displacement of the clavicular head.
Prevents posterior dislocation of the clavicular head into the superior mediastinum. It is the critical ligamentous restraint protecting the trachea, oesophagus, great vessels, and brachial plexus from displaced clavicular bone.
Posterior SC joint dislocation, though accounting for fewer than 5% of all SC dislocations, is a vascular surgical emergency because the clavicular head can compress or lacerate the subclavian vessels, trachea, and oesophagus. CT is mandatory for diagnosis. Closed reduction under general anaesthesia, with a thoracic surgeon on standby, is attempted first. Open reduction and ligament reconstruction with tendon graft is performed for irreducible or recurrent cases.
High-energy force drives the clavicular head posterior to the sternum, compressing mediastinal structures and producing dysphagia, dyspnoea, hoarseness, or vascular compromise requiring urgent CT evaluation and emergent reduction with vascular surgical standby.
