Thoracic Outlet Syndrome

If you have numbness and tingling in your arms or pain in your shoulders, especially when you raise your arms, you could have thoracic outlet syndrome (TOS). The thoracic outlet is the narrow space between your collarbone and top rib. Muscles run through it from your neck to your shoulder, along with the nerves and blood vessels that go down your arm. When something presses on them, you can have pain and other symptoms.

What Are the Types?

There are 3 types of thoracic outlet syndrome:

  • Neurogenic: Affects nerves leading from the spinal cord to the neck to the arm. Most thoracic outlet syndrome cases involve nerves.
  • Venous: Affects veins
  • Arterial: Affects arteries

About 95% of thoracic outlet syndrome cases involve nerves. It’s rare but more serious when it affects a vein or an artery.

The condition is more common in women. It’s also often seen in athletes and workers who make repeated arm motions. But it can affect anyone.

What Are the Symptoms?

You’re most likely to feel them in your arms and hands. They include:

  • Pain in the neck, shoulder, or arm
  • Numbness and tingling
  • Swelling
  • Weakness
  • Discoloration -- blue, red, or pale
  • Cold hands

What Causes It?

There are several causes:

  • Injuries: Whiplash, a broken collarbone, or other injury can leave scar tissue and inflammation.
  • Poor posture: When your shoulders slump, your collarbones can move out of place and press on your nerves. Weak shoulder muscles can cause bad posture.
  • Repetitive stress: It can affect people who move their arms in a certain way, like swimmers, volleyball players, and baseball pitchers.
  • Physical defects: Some people are born with an extra rib or a thoracic outlet that’s smaller than normal.
  • Obesity: Extra weight can put stress on the muscles that support your collarbones.

How Is It Diagnosed?

Your doctor will start by asking questions to get a detailed history of your symptoms and then do a physical exam.

Neurogenic: This type isn’t always easy to spot. Things can compress the nerves that serve your arms and hands in different places for a variety of reasons. The symptoms will be the same, but the problem could be arthritis in your neck, a pinched nerve, or carpal tunnel syndrome. Other conditions like a damaged rotator cuff, fibromyalgia, and multiple sclerosis can cause pain and numbness in your shoulders and arms. Another example is thinning or wasting of the muscle at the base of the thumb. This can happen with carpal tunnel syndrome too.


Venous and arterial: These symptoms are more obvious. Blood doesn’t circulate properly. You may even have a blood clot. Your arm or hand may be swollen, and look either pale or bluish. You may have a weak pulse or no pulse in the affected arm.

Several kinds of tests can help with the diagnosis:

  • Positioning tests: The doctor will move your arms and head in different ways to see if the symptoms appear. One shortfall: These tests can also cause symptoms in healthy people.
  • Scalene muscle block: The doctor will give you a shot that relaxes muscles in this area to see if that makes the symptoms go away.
  • Imaging tests: An X-ray, CT scan, or MRI can reveal an extra rib or other abnormal physical feature. An ultrasound can look for blockages or narrowing of blood vessels.
  • Nerve tests: Results are usually normal in people with this condition, but they can rule out other causes.
  • Blood circulation tests: An arteriogram or venogram (tests that use dyes and X-rays to see how blood flows in your system) can show blood clots or other damage to blood vessels.

How Is It Treated?

Management of TOS depends on the type.

Neurogenic: The usual treatments are:

  • Physical therapy: You’ll do exercises to stretch and strengthen muscles in your neck and shoulders and improve your posture. This may be all you need to get relief.
  • Medication: The doctor may recommend that you use a muscle relaxant or that you take ibuprofen or naproxen to ease pain and swelling. You may hear your doctor call these NSAIDS, or non-steroidal anti-inflammatory drugs.
  • Surgery is sometimes an option, but it doesn’t work nearly as well for this type of TOS.

Venous and arterial: First you’ll be treated for any possible blood clots. Then you’ll most likely need a type of surgery called thoracic outlet decompression. Your surgeon will open up the space for the nerves and blood vessels to pass through. They may remove extra bone or other tissue, and cut or remove muscles that are causing the compression. They’ll also fix or bypass damaged blood vessels.

If other treatments don’t fix your symptoms, you may need long-term pain management. You may need medication. Your doctor may advise you to get to a healthy weight. Changes at work or with everyday activities may also help. For example, you can set up your work station to support good posture. You can also avoid things that aggravate the condition, like carrying a heavy bag on your shoulder.

WebMD Medical Reference Reviewed by Louise Chang, MD on January 19, 2019



National Institute of Neurological Disorders and Stroke: “Thoracic Outlet Syndrome Information Page.”

American Academy of Orthopedic Surgeons: “Thoracic Outlet Syndrome.”

Society for Vascular Surgery: “Thoracic Outlet Syndrome.”

National Organization for Rare Disorders: “Thoracic Outlet Syndrome.”

Cleveland Clinic: “Thoracic Outlet Syndrome (TOS.)”

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