Radiographic findings of spontaneous subluxation of the sternoclavicular joint.

Eight middle-aged women with spontaneous atraumatic subluxation of the sternoclavicular joint were evaluated with radiography and computed tomography. All patients were employed in occupations involving moderate to heavy physical labour, and no patients could recall a specific traumatic incident associated with onset of symptoms. In seven of the eight patients, the displacement of the medial clavicle was in a cranial direction; in four of the eight patients, there was an associated anterior subluxation, and in one patient, the subluxation was purely anterior. All five patients with an anterior component to the sternoclavicular subluxation had associated condensing osteitis of the clavicle. The sclerosis of the medial clavicle is possibly the result of chronic abrasion on the sternum and first costal cartilage in association with normal respiration and with upper extremity motion.