TOS involves the compression of the neurovascular bundle as it exits the thoracic girdle. Approximately 95% of all patients suffering from this syndrome are neurogenic (nTOS). nTOS patients often complain of pain and numbness in their fingers, hands, or arms on the affected side. Often as a result of some type of trauma. Often a  description of a history of vigorous repetitive activity is encountered. Venous TOS (vTOS) makes up an additional 3–5% of patients, also described as “effort thrombosis” or Paget-Schroetter syndrome. Arterial TOS (aTOS) is the rarest form accounting for only 1-2%.