The thoracic outlet syndromes.

The term thoracic outlet syndrome (TOS) refers to a heterogeneous group of disorders, all of which have in common compression of one or more neurovascular elements at some point within the thoracic outlet. Of the five disorders comprising this group, four have all of the features expected of a syndrome-a recognized constellation of clinical features; an anatomic derangement accounting for these features; and a method of testing that identifies the anatomic derangement. Consequently, their recognition and management are relatively straightforward. Conversely, one of these five disorders (nonspecific TOS) lacks these correlations, which has generated considerable debate in the literature and caused some experts to doubt its existence altogether. The primary focus in this study is on the neurologic forms of TOS. However, for completeness and a better understanding of these neurologic manifestations, the vascular forms are also reviewed.