A sledgehammer on the brachial plexus: thoracic outlet syndrome, subclavius posticus muscle, and traction in aggregate.

Reported here is a 30-year-old man who was seen because of pain and weakness in the upper extremities after a tractional injury. Physical examination revealed significant atrophy in the left deltoid and right intrinsic hand muscles, generalized hypoesthesia, decreased deep tendon reflexes bilaterally, and decreased strength in various muscle groups. Roos (right) and hyperabduction (bilateral) tests were positive. Electrodiagnostic studies were consistent with bilateral brachial plexopathy. Cervical radiographs showed long transverse process of C7 on the right side and a small rudimentary rib articulating with C7 on the left side. Brachial plexus magnetic resonance imaging demonstrated an aberrant muscle and compressive brachial plexus injury on the left side. Surgery via transaxillary approach was performed on the left side. The occurrence of traumatic brachial plexopathy in the presence of underlying thoracic outlet syndrome and subclavius posticus muscle is discussed for the first time in the literature.