A 22-year-old man presented with a one year history of rightsided shoulder pain, hand weakness and tingling, and purplish discoloration of the upper extremity upon abduction. He had congenital pseudarthrosis of the right clavicle since childhood. Aside from an obvious deformity characterized by asymmetry of the shoulders and a palpable bony depression over the right clavicle, the patient had been previously asymptomatic. Physical examination revealed the musculoskeletal deformities as described, as well as prominent veins over his right shoulder, arm, and chest. With arm elevation, his right arm became dusky and his radial pulse diminished. Neurologically, the patient had no deficits except for mild weakness (Grade 4+/5) of the ulnarinnervated intrinsic muscles of the right hand. The clinical findings were consistent with a combined neurogenic and vascular form of thoracic outlet syndrome.