Asymptomatic enlargement of the clavicle: a review of underlying aetiologies.

An asymptomatic enlargement of the medial clavicle is a condition that is often both missed and misdiagnosed. We review the most common causes of an isolated and asymptomatic enlargement of the medial clavicle. Underlying aetiologies include osteoarthritis of the sternoclavicular joint, condensing osteitis, spontaneous dislocation of the sternoclavicular joint, and sternocostoclavicular hyperostosis. Key points in the history and physical examination as well as characteristic radiographic findings are sufficient for correct diagnoses. Treatment is conservative.