What is thoracic outlet syndrome?

Thoracic outlet syndrome is a variety of symptoms that happen from a narrowing of your thoracic outlet. This is the space between your collarbone and your first rib. It can result from injury, disease, or a problem you had from birth.

The thoracic outlet is a narrow space between your collarbone (clavicle) and your first rib. Nerves and blood vessels exit from your chest to your arm through this space. This includes:

• The subclavian artery, a very large main artery

• The subclavian vein, a large main vein

• The brachial plexus, a bundle of nerves that serve your shoulder, arm, and hand

Your shoulder muscles normally keep your clavicle raised and in place.

Many health problems can cause your collarbone to slip down and forward. This narrows the thoracic outlet. It puts pressure on the nerves and blood vessels here. This causes the symptoms of thoracic outlet syndrome.

Healthcare providers sometimes categorize thoracic outlet syndrome by its underlying cause. For instance, cervical rib syndrome is a type of thoracic outlet syndrome that can happen if a person has an extra upper rib. Experts also sometimes categorize thoracic outlet syndrome by the structures compressed. Nerve, vein, and artery compression may all cause different symptoms. But there might be compression on more than 1 structure.

Thoracic outlet syndrome is not common. Women get it more often than men do. It can happen in people of any age. But it's more common in younger adults.

What causes thoracic outlet syndrome?

Thoracic outlet syndrome results from the compression of nerves and blood vessels between your upper rib and your collarbone. Health problems that can cause this include:

• Having an extra rib from birth

• Having an abnormality in your neck muscles from birth

• Neck injury

• Injury to the first rib or collarbone

• Repetitive overhead arm movements (which may cause inflammatory changes)

Who is at risk for thoracic outlet syndrome?

Awkward postures, often work-related, and extreme obesity may raise your risk of thoracic outlet syndrome. People who do repetitive overhead arm movements (like swimmers or pitchers) may also have a higher risk.

What are the symptoms of thoracic outlet syndrome?

Symptoms of thoracic outlet syndrome relate to the compression of blood vessels and nerves. Possible symptoms are:

• Pain. A sharp or dull aching, mainly in the arm or hand. It may occur more often with activity, when raising your arm, or when carrying heavy objects.

• Autonomic and vascular symptoms. Mainly changed sweating, skin temperature, and color, which can occur with swelling. Some people feel that their arm is warm or cold. In extreme cases, poor blood flow to the fingers can lead to gangrene.

• Weakness. Lack of endurance and hand clumsiness, especially when working with the arms over the head or when lifting heavy objects.

Your symptoms may come and go, partly based on your activity level. Overhead activities may worsen your symptoms. The nature and severity of your symptoms may vary by which structures are being compressed. Most people have symptoms on only 1 side. At times, a problem causes thoracic outlet syndrome on both sides of the body.

How is thoracic outlet syndrome diagnosed?

Your healthcare provider will start with a health history. They'll ask you about your past health problems and all your symptoms. You'll also need a physical exam. Your provider may try to reproduce your symptoms, examining your hand and arm in many positions.

Providers often use a specific test to help diagnose thoracic outlet syndrome. Your provider may have you raise your arms and then open and close your fist for a few minutes. This often brings on symptoms if you have thoracic outlet syndrome.

Your provider may also order specific tests to help make the diagnosis. You may need:

• Nerve conduction tests, to see how your nerves are affected

• Doppler ultrasound, to detect blood flow through your arm and hand

• Chest X-ray, to find abnormalities of bone such as an extra rib

• CT scan or MRI, if the healthcare provider needs to see more detail

• CT angiography or MR angiogram (MRA), to get more information about blood flow through your arm

Seeing a specialist is sometimes needed to diagnose thoracic outlet syndrome. Thoracic outlet syndrome is often harder to diagnose than other more common problems of the shoulder.

How is thoracic outlet syndrome treated?

Possible treatments of thoracic outlet syndrome are:

• Physical therapy to help build up your shoulder muscles, improve your posture, and enlarge the thoracic outlet space

• Over-the-counter pain medicines to ease pain and swelling

• Weight loss, if you're overweight

• Changes in everyday activities, including those at work, that bring on symptoms

These treatments ease symptoms in most people. If you still have major symptoms after trying these treatments, your healthcare provider might advise surgery. For instance, your healthcare provider might remove an extra first rib (if present). Sometimes providers release an abnormal muscle in your neck. Or they do surgery on the blood vessels of the neck. The exact kind of surgery will depend on the anatomy of your thoracic outlet. Surgery eases symptoms in many people.

Healthcare providers don't advise treatment for people who have an extra rib unless they show signs of thoracic outlet syndrome.

What are possible complications of thoracic outlet syndrome?

Sometimes this condition causes a blood clot to form somewhere in the veins of your arm, blocking the flow of blood. This may make your arm very swollen. The clot may also move to the lungs (pulmonary embolism) or somewhere else. Your healthcare provider might need to treat this with medicines to prevent clotting (blood thinners). You also might need a procedure to remove the clot using a thin tube (catheter) inserted through a vein.

Thoracic outlet syndrome may also cause a blood clot to form in one of the arteries of your arm. This might cause sudden decreased blood flow to your arm. Your provider may need to treat this clot using blood thinners or a catheter inserted through an artery. Sometimes providers may use surgery to remove the clot instead.

Coping with thoracic outlet syndrome

If you have thoracic outlet syndrome, you can ease your symptoms and help prevent them from coming back.

Don't carry heavy bags over your shoulder. This increases pressure on the thoracic outlet. You should also do your physical therapy exercises to help keep your shoulder muscles strong. Doing these regularly may help keep your symptoms from coming back.

When should I call my healthcare provider?

Call your provider right away if your arm or hand becomes suddenly cool, lighter in color, or swollen. You may have a blood clot. Let your provider know right away about any other sudden changes in your symptoms, like sudden weakness of your hand. If your symptoms are not getting better with therapy, plan to see your provider soon.

Key points about thoracic outlet syndrome

• Thoracic outlet syndrome is a variety of symptoms that happen from a narrowing of your thoracic outlet. This is the space between your collarbone and your first rib. It can compress arteries, veins, and nerves in the region.

• The condition can result from injury, disease, or a problem you had from birth.

• You may have symptoms from nerve compression, like pain, tingling, or weakness in your arm or hand. Or you may have symptoms from blood vessel compression, like a swollen arm, or an arm that is pale and cool.

• Most people with this condition don't need surgery. Your healthcare provider may prescribe physical therapy, changes in your regular activities, or pain medicines to reduce your symptoms.

• Some people with thoracic outlet syndrome develop blood clots in the veins or arteries of their arm. You might need a medicine and surgery if this happens.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

• Know the reason for your visit and what you want to happen.

• Before your visit, write down questions you want answered.

• Bring someone with you to help you ask questions and remember what your provider tells you.

• At the visit, write down the name of a new diagnosis and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.

• Know why a new medicine or treatment is prescribed and how it will help you. Also know what the side effects are.

• Ask if your condition can be treated in other ways.

• Know why a test or procedure is advised and what the results could mean.

• Know what to expect if you do not take the medicine or have the test or procedure.

• If you have a follow-up appointment, write down the date, time, and purpose for that visit.

• Know how you can contact your provider if you have questions.