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How is thoracic outlet syndrome (TOS) diagnosed?

Dr. Joshua I. Greenberg, MD
Vascular Surgeon

Thoracic outlet syndrome (TOS) is diagnosed by careful review of patient history and performing a complete physical examination. No single diagnostic test has sufficient specificity to prove or exclude the diagnosis. TOS can be diagnosed by the following findings:

Patient history:

  • summarize findings from multiple previous physicians
  • antecedent trauma, both overuse and accidental
  • head and neck symptoms
    • muscle spasm
  • sensory changes
    • glove like numbness
    • ulnar numbness
    • pain
  • motor changes
    • intrinsic hand weakness (note that true weakness is uncommon)
    • clumsiness
  • vascular signs and symptoms
    • swelling
    • effort-induced weakness or sensory changes
    • thrombosis or thrombophilia history

Physical exams:

  • circulatory exam
  • positioning tests
    • Allen test
    • Adson’s test (positive in many healthy patients)
    • Military posture test
  • motor and sensory tests
  • carpal tunnel tests
  • cervical spine tests
  • neck exam
    • bruits
    • scalene tenderness
    • plexus tenderness
  • elevated arm exercise test

One of the most important things to know about thoracic outlet syndrome is that it's very difficult to diagnose, since its symptoms are commonly mistaken for other conditions. During the exam, your doctor will look for any signs of nerve or blood vessel compression as well as any physical abnormalities in the shoulders, arms, and hands. If further testing is needed, your doctor may order an X-ray or MRI of the thoracic outlet. Nerve conduction studies and electromyography are also used to help diagnose this disorder and rule out other conditions.

Doctors use a combination of imaging studies including chest x rays, CT scans (in some cases with 3-dimensional reconstruction to show compression of the structures at the thoracic outlet), angiography and venography, MRI, ultrasonography, electromyography (EMG), and nerve conduction studies to diagnose thoracic outlets obstructions and determine the most effective treatment.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.