ABSTRACT
Thoracic outlet syndrome (TOS) is a proximal entrapment neuropathy of the upper limb. Somedmes an X-ray will demonstrate a cervical rib, but in less straightforward situations there is no cervical rib and yet neurovascular signs and symptoms are found. Several authors have identified anatomical variations at the cervico-brachial junction (Shore 1926, Adson and Coffey 1927, Gage and Pamell 1947, Leblanc 1937, Delmas 1938, Kirgis and Reed 1947, Fernandez 1957, Naffziger and Grant 1938, Rosati and Lord 1961, Sunderland 1978, Poitevin 1982, 1986, 1988a, 1988b, 1988c, 1988d, 1991, 1993, Narakas et al 1986). Roos (1976, 1979, 1982) has described nine different types of bands (Wood et al 1988); however, interpretation of these bands is not always clear. This chapter describes stxidies that aimed to determine the anatomic and functional variations in the arrangement of the scalene muscles, their importance in causing thoracic outle t syndro me and whe the r the ‘abn ormal’ mus fibrous bands are anatomical variations.
