The thoracic outlet syndromes: Part 2. The arterial, venous, neurovascular, and disputed thoracic outlet syndromes.

The thoracic outlet syndromes (TOSs) are a group of etiologically and clinically distinct disorders with 1 feature in common: compression of 1 or more neurovascular elements as they traverse the thoracic outlet. The medical literature reflects 5 TOSs: arterial; venous; traumatic neurovascular; true neurogenic; and disputed. Of these, the first 4 demonstrate all of the features expected of a syndrome, whereas disputed TOS does not, causing many experts to doubt its existence altogether. Thus, some categorize disputed TOSs as cervicoscapular pain syndrome rather than as a type of TOS. To better understand these disorders, their distinctions, and the reasoning underlying the categorical change of disputed TOS from a form of TOS to a cervicoscapular pain syndrome, a thorough understanding of the pertinent anatomy, pathology, pathophysiology, and electrodiagnostic manifestations of these pathophysiologies is required. This review of the TOSs is provided in 2 parts. In part 1 we covered general information pertinent to all 5 TOSs and reviewed true neurogenic TOS in detail. In part 2, we review the arterial, venous, traumatic neurovascular, and disputed forms of TOS. Muscle Nerve 56: 663-673, 2017. © 017 American Association of Neuromuscular & Electrodiagnostic Medicine.