Thoracic Outlet Syndrome



The thoracic outlet is the area of the lower neck and upper chest. This area has a variety of nerves, blood vessels, muscles, and bones that run through a fairly small area. When the nerves and blood vessels of this area are compressed, irritated, or injured, they can cause a range of symptoms known as thoracic outlet syndrome (TOS).

Thoracic Outlet Syndrome
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Compression, injury, or irritation of nerves and blood vessels can be caused by:

  • Defects in nearby structures
  • Poor posture
  • Trauma
  • Repetitive arm or shoulder movement
  • Tumors

Risk Factors

Factors that may increase your chance of thoracic outlet syndrome include:

  • Having an abnormal first rib
  • Poor posture
  • Repetitive motion
  • Trauma
  • Obesity



Thoracic outlet syndrome may cause the following:

  • Arm or hand pain
  • Arm or hand weakness
  • Numbness and tingling
  • Cold sensitivity in the hands and fingers
  • Pain or sores of the fingers
  • Poor blood circulation to the arm, hands, and fingers
  • Swelling of the limb
  • Skin of arm turning pale and blue


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

During an elevated arm stress test, your doctor will ask you to hold your arms and head in positions that may cause the thoracic outlet syndrome (TOS) symptoms to reappear. The results of these tests will help determine whether you have TOS and rule out other possible related conditions.

Other tests may include:

  • Blood tests
  • Electromyography, other nerve conduction tests

Images of internal body structures may be taken with:

  • Chest x-ray
  • Ultrasound
  • CT angiography
  • MRI scan
  • Venography



Treatment varies depending on your specific symptoms. In most cases, thoracic outlet syndrome is managed with pain medication and physical therapy.


Your doctor may recommend the following:

  • Nonsteroidal anti-inflammatory drugs (NSAIDs)
  • Muscle relaxers
  • Antidepressants
  • Blood thinners
  • Anti-platelet medications

Physical Therapy

A physical therapist will design some exercises for you. The exercises will help to relieve symptoms by relaxing nearby muscles, improving posture, and reducing pressure on nerves and blood vessels.

Lifestyle Changes

As part of your treatment, you may need to make lifestyle changes:

  • Avoid activity that causes pain
  • Practice good posture
  • Avoid repetitive motion
  • Change your workstation layout
  • If you are overweight, talk to your doctor about how you can lose weight
  • Exercise regularly to improve strength, flexibility, and range of motion


If other treatments fail, your doctor may recommend surgery. The goal of surgery is to move or remove the source of the compression. In some people, this may involve removing part or all of the first rib to make more room for the nerves and blood vessels.


There are no current guidelines to prevent thoracic outlet syndrome.

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

Edits to original content made by Denver Health.

a (TOS)


Occupational Safety and Health Administration 

The Nicholas Institute of Sports Medicine and Athletic Trauma (NISMAT) 


Canadian Centre for Occupational Health and Safety 

Public Health Agency of Canada 


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