Thoracic outlet syndrome is caused by rib anomalies or musculofibrous bands between the clavicle, cervical spine, and first rib. An anomalous anterior scalene muscle is the most common cause. Any condition which narrows the costoclavicular space may cause the symptom complex. These patients experience ischemic symptoms in the arms with abduction, associated with loss of the radial pulse and possibly a subclavian bruit. Complications include poststenotic aneurysm, subclavian artery thrombosis, mural thrombus with distal embolization, or venous thrombosis.
Surgery can be curative.