The scalenus medius band and the seventh cervical transverse process.

A case is reported of compression of the lowest trunk of the brachial plexus by a fibrous scalenus medius band. The band, when present, connects the transverse process of the seventh cervical vertebra, to the first rib. Its presence may on occasions be inferred from the abnormal shape of the seventh cervical transverse process. Similar case reports are reviewed. A study of the length and shape of the transverse process in symptoms-free patients was contrasted with the appearance in a patient with a scalenus medius band and symptoms of brachial neuritis. It is concluded that the shape rather than the length of the process is the clue to the diagnosis.