Cervical Ribs and the Scalenus Muscle Syndrome.
—Patterson1 delves into comparative anatomy to show why cervical ribs occur and to predict anatomic arrangements and into embryology to tell why certain ribs produce symptoms. He lists the anatomic types under four broad heads:1. Enlarged transverse process, usually the seventh cervical.2. Bilateral ribs of the floating type or articulating with the first ribs.3. Unilateral ribs of the floating type or articulating with the first rib.4. Rudimentary tip ribs, either single or bilateral.He calls attention to the facts that during operation traction on the brachial plexus may produce symptoms lasting for months and that the scalenus muscle should be divided at least 1 or 2 inches (2.5 to 5 cm.) above the first rib because the pleura frequently comes up behind this muscle. In many cases simple division is all that is needed for relief