The thoracic outlet is the area of the shoulder/neck where the nerves (brachial plexus) and blood vessels (subclavian vessels) pass from the cervical area toward the axilla. Thoracic outlet syndrome (TOS) is a set of symptoms due to compression and/or irritation of these vessels and nerves. There is much controversy among physicians and diagnosing this syndrome is very difficult. It is often confused with carpal tunnel syndrome, brachial plexus syndrome, rotator cuff syndrome, and bursitis. Always see your MD or an MD specialist for diagnosing this syndrome and getting the OK for deep tissue massage first.