The thoracic outlet lies at the lower part of the neck, beginning just above and behind the collarbone and extending into the upper arm and chest. Thoracic Outlet Syndrome results when the nerves and blood vessels in this area are compressed, resulting in pain, weakness, fatigue and numbness or tingling in the arm or hand, particularly with activities in which the arm is elevated.
During surgery to correct Thoracic Outlet Syndrome, both the first rib -- the uppermost of the ribs, which is attached to the first thoracic vertebrae at the base of the neck, angles down and connects to the sternum just below the collarbone -- and the scalene muscles are removed to clear space for the nerves in the thoracic outlet.
Typical recovery time
Fewer than 20 Major League pitchers had undergone Thoracic Outlet Syndrome surgery as of March 2017, so the recovery timeline is still inexact. But even in a best case scenario, a pitcher is unlikely to be ready to return until at least 12 weeks after the procedure.