The thoracic outlet is the narrow space between the collarbone and first rib. When the nerves or blood vessels become compressed, this can cause pain in the arms, shoulders, and neck; as well as numbness and tingling in hands, and weakness in hands.
The exact cause is unknown, but might be triggered by the physical trauma of car accidents or sports-related injuries, repetitive arm motions, or specific structural abnormalities. These abnormalities may take the form of anatomical defects (for example individuals born with an additional rib), pregnancy, tumors (in rare cases), and, of course, posture specifically forward head posture. Thoracic Outlet Syndrome (TOS) is often the underlying cause of refractory upper limb conditions such as frozen shoulder and carpal tunnel syndrome.
There are specific massage techniques used to loosen the muscles in that can cause the compression for TOS. After a person has been diagnosed with TOS their doctor will often prescribe massage, physical therapy and medication to help with pain management. When symptoms do not improve, surgery is then considered.