[Thoracic outlet syndrome due to first rib anomaly: a case report].

Compared to cervical rib, first rib anomaly is less familiar to us as a cause of thoracic outlet syndrome. We report a case of thoracic outlet syndrome due to first rib anomaly. A 50-year-old man was admitted to our hospital because of right arm pain when his arm was raised up. Chest X-ray showed an abnormal right first rib which made a J-shaped curve and was attached to the second rib. A palpable mass was noted in the supraclavicular region. Angiography revealed complete occlusion of the right subclavian artery in the Allen test position. During conservative therapy for two months, the symptom was gradually getting worse. We performed resection of the right first rib and anterior scalenotomy by the supraclavicular approach. The patient made a good recovery after the surgery. Postoperative angiogram showed no stenotic lesion of the right subclavian artery. If a patient has complaints suggesting compression of the subclavian neurovascular bundle, we should be careful not to overlook the first rib anomaly on chest X-ray.