Thoracic Outlet Syndrome (TOS) is an umbrella term which describes the compression of blood vessels, nerves, arteries, and veins as they exit through the space between the collar bone and the first rib. This space is known as the thoracic outlet (cervico thoraco brachial) region. Neurovascular compression, that is compression of nerves and blood vessels, often causes pain, pins and needles or reduced sensation in the arm, shoulder and neck. If left untreated, TOS can lead to increased pain and decreased function of the structures involved and in severe cases, blood clots can form which is extremely detrimental to health.