Thoracic Outlet Compression Syndromes (TOS) By Michael Rubin, MDCM, New York Presbyterian Hospital-Cornell Medical Center Reviewed / Revised Apr 2022 | Modified Sep 2022 View Patient Education Symptoms and Signs Diagnosis Treatment Key Points Thoracic outlet compression syndromes are a group of poorly defined disorders characterized by pain and paresthesias in a hand, the neck, a shoulder, or an arm.