by EBSCO Medical Review Board


The thoracic outlet is the site of the lower neck and upper chest. It has a many nerves, blood vessels, muscles, and bones that run through a small site. Thoracic outlet syndrome (TOS) is when the nerves and blood vessels are squeezed, irritated, or harmed.

Thoracic Outlet Syndrome
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TOS may be due to:

  • Defects in nearby structures
  • Trauma
  • Poor posture

Risk Factors

Your risk of TOS is raised if you have:

  • An extra rib or a first rib that is not typical
  • Trauma
  • Motions that you repeat often
  • Job problems, such as poor posture or using the computer too much


TOS may cause:

  • Arm or hand pain
  • Lack of arm or hand strength
  • Numbness and a feeling of pins and needles
  • Cold sensitivity in the hands and fingers
  • Pain or sores of the fingers
  • Poor blood flow to the arm, hands, and fingers
  • Swelling
  • Skin of arm turning pale and blue


Your doctor will ask about your symptoms and health history. A physical exam will be done.

Your doctor will ask you to hold your arms and head in positions that may cause TOS. The results of these tests will help show whether you have TOS.

You may also have:

Pictures may be taken with:


Treatment depends on the symptoms that you have. In most cases, TOS is treated with pain medicine and physical therapy.


You may need to take:

  • Nonsteroidal anti-inflammatory drugs (NSAIDs)
  • Muscle relaxants
  • Antidepressants
  • Blood thinners
  • Anti-platelet medicines

Physical Therapy

A therapist will make an exercise plan. It will help to ease symptoms by relaxing nearby muscles, making your posture better, and easing pressure on nerves and blood vessels.

Lifestyle Changes

You may need to:

  • Avoid activity that causes pain.
  • Practice good posture.
  • Avoid repetitive motion.
  • Change your workstation layout.
  • Exercise regularly.


If other treatments fail, your doctor may advise surgery. The goal is to move or remove the source of the pressure. In some people, this may mean taking out part or all of the first rib. This can make more room for the nerves and blood vessels.


TOS can’t be prevented.


Occupational Safety and Health Administration 

The Nicholas Institute of Sports Medicine and Athletic Trauma 


Canadian Centre for Occupational Health and Safety 

Public Health Agency of Canada 


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Povelson S, Povlsen B. Diagnosing thoracic outlet syndrome: current approaches and future directions. Diagnostics (Basel). 2018;8(1):pii E21.

Thoracic outlet syndrome. Ortho Info—American Academy of Orthopaedic Surgeons website. Available at: Updated March 2018. Accessed March 17, 2020.

Thoracic outlet syndrome. EBSCO DynaMed Plus website. Available at:  . Updated December 22, 2014. Accessed March 17, 2020.

Thoracic outlet syndrome. National Institute of Neurological Disorders and Stroke website. Available at: Accessed March 17, 2020.

Vanti C, Natalini L, Romeo A, Tosarelli D, Pillastrini P. Conservative treatment of thoracic outlet syndrome. A review of the literature. Eura Medicophys. 2007 Mar;43(1):55.

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