NINDS Thoracic Outlet Syndrome Information Page

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What is Thoracic Outlet Syndrome?

TOS is an umbrella term that encompasses three related syndromes that cause pain in the arm, shoulder, and neck:  neurogenic TOS (caused by compression of the brachial plexus), vascular TOS (caused by compression of the subclavian artery or vein) and nonspecific or disputed TOS (in which the pain is from unexplained causes).  Occasionally, neurogenic TOS and vascular TOS co-exist in the same person.  Most doctors agree that TOS is caused by compression of the brachial plexus or subclavian vessels as they pass through narrow passageways leading from the base of the neck to the armpit and arm, but there is considerable disagreement about its diagnosis and treatment.
Making the diagnosis of TOS even more difficult is that a number of disorders feature symptoms similar to those of TOS, including rotator cuff injuries, cervical disc disorders, fibromyalgia, multiple sclerosis, complex regional pain syndrome, and tumors of the syrinx or spinal cord.  Symptoms of TOS vary depending on the type.

           Neurogenic TOS has a characteristic sign, called the Gilliatt-Sumner hand, in which there is severe wasting in the fleshy base of the thumb.  There may be numbness along the underside of the hand and forearm, or dull aching pain in the neck, shoulder, and armpit. 

          Vascular TOS features pallor, a weak or absent pulse in the affected arm, which also may be cool to the touch and appear paler than the unaffected arm.  Symptoms may include numbness, tingling, aching, and heaviness. 

           Non-specific TOS  most prominently features a dull, aching pain in the neck, shoulder, and armpit that gets worse with activity.  Non-specific TOS is frequently triggered by a traumatic event such as a car accident or a work related injury.  It also occurs in athletes, including weight lifters, swimmers, tennis players, and baseball pitchers. 

TOS is more common in women.  The onset of symptoms usually occurs between 20 and 50 years of age.  Doctors usually recommend nerve conduction studies, electromyography, or imaging studies to confirm or rule out a diagnosis of TOS.

Is there any treatment?

What is the prognosis?

What research is being done?

NIH Patient Recruitment for Thoracic Outlet Syndrome Clinical Trials

• At NIH Clinical Center
• Throughout the U.S. and Worldwide

Organizations

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Last updated June 20, 2008