Diagnosis: First rib pseudarthrosis
The computed tomogram showed that the hypoplastic first ribs were fused to the second ribs by means of an osseous projection from the second rib that formed a pseudojoint with the first rib. Rib anomalies are common, occurring in 1.4% of young men in a large series in which chest radiographs were studied in military recruits. Cervical ribs are the most commonly encountered abnormality, although estimates of their incidence vary widely, from 0.2% to 8%.1 They may produce thoracic outlet syndrome owing to pressure on the brachial plexus, subclavian artery, or subclavian vein,2 as well as a palpable mass in the supraclavicular fossa.