The anterior sternoclavicular ligament is a broad, flat fibrous band reinforcing the anterior capsule of the sternoclavicular joint. It runs from the anterior surface of the sternal end of the clavicle downward and medially to the anterior surface of the manubrium and adjacent first costal cartilage. Together with the posterior SC ligament, interclavicular ligament, costoclavicular ligament, and intraarticular disc it forms the SC joint stabilising complex.
Primary restraint against anterior displacement of the clavicular head, resisting forces that would displace the medial clavicle anteriorly. In contrast, the posterior sternoclavicular ligament is the stronger restraint against the rarer and more dangerous posterior dislocation.
Anterior sternoclavicular dislocation is more common than the posterior variety and occurs from direct anterior-to-posterior force on the clavicle, typically from a direct blow. The dislocated clavicular head produces a visible and palpable anterior prominence. Most anterior dislocations can be managed conservatively in a figure-of-eight bandage, as the anterior ligament has less capacity than the posterior to endanger mediastinal structures if not fully reduced.
Anterior clavicular head displacement from the sternum following direct anterolateral chest trauma produces a visible step and local tenderness managed conservatively in most cases, though the cosmetic deformity from a persistent unreduced dislocation is accepted in low-demand patients given the surgical complexity of open reduction.
