The rudimentary first rib. A cause of thoracic outlet syndrome with arterial compromise.

The symptoms of thoracic outlet syndrome are neurologic, not vascular, in more than 95% of cases. Subclavian artery compression is usually related to cervical ribs; however, congenitally abnormal first ribs may also produce vascular compromise. We review our two cases of thoracic outlet syndrome associated with significant subclavian artery compression caused by rudimentary first ribs and the prior literature emphasizing the mechanism of injury, diagnostic features, and treatment. Transaxillary resection of the first and second ribs was curative in both cases. The operative specimens demonstrated fusion of the rudimentary first rib to the second rib, with compression of the subclavian artery by a large first-rib exostosis. Patients with thoracic outlet syndrome and a rudimentary first rib should be examined for substantial vascular compromise, and, if it is found, the abnormal first and second rib complex should be resected early without prolonged conservative measures.