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Thoracic Outlet Syndrome

This article from our Health Library is for educational purposes. Please contact us with questions specific to the services we provide, to find a doctor or to schedule an appointment.

Thoracic outlet syndrome refers to a variety of symptoms that happen from a narrowing of your thoracic outlet—the space between your collarbone and your first rib. It can result from injury, disease, or a problem present 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 passageway. This includes a very large important artery (the subclavian artery), a large and important vein (the subclavian vein), and a bundle of nerves that serve your shoulder, arm, and hand. Your shoulder muscles normally keep your clavicle elevated and in place.

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

Healthcare professionals sometimes categorize thoracic outlet syndrome according to its underlying cause. For example, “cervical rib syndrome” refers to a type of thoracic outlet syndrome that can happen if a person has an extra upper rib. Clinicians also sometimes categorize thoracic outlet syndrome according to the structures compressed. Nerve, vein, and artery compression may all cause different symptoms (though there might be compression on more than one structure).

Thoracic outlet syndrome is relatively uncommon. Women get it more often than men do. It can happen in people of any age.

Thoracic outlet syndrome results from the compression of nerves and blood vessels between your upper rib and your collarbone. Conditions 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)

Poor posture and obesity may increase your risk of thoracic outlet syndrome. People who do repetitive overhead arm movements (like swimmers or pitchers) may also have an increased risk.

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

  • Aching in your neck, shoulder, arm, or hand
  • Pain, numbness, or tingling of your forearm or fingers
  • Hand weakness
  • Limited range of motion of your arm
  • Depression of your shoulder
  • Tenderness of your neck muscles
  • Swelling and redness of your arm (or, less commonly, from reduced blood flow out of your arm)
  • Pale and cool arm and hand (or, even less commonly, from reduced blood flow into your arm)

Your symptoms may come and go, partially based on your activity level. Overhead activities may worsen your symptoms. The nature and severity of your symptoms may vary according to which structures have compression on them. Most people have symptoms on only one side. Occasionally, a problem causes thoracic outlet syndrome on both sides of the body.

Your healthcare provider will begin with a thorough medical history, asking you about your past medical problems and all of your present symptoms. You will also need a thorough physical exam. Your healthcare provider may try to reproduce your symptoms, examining your hand and arm in multiple positions.

Healthcare providers often use a specific test to help diagnose thoracic outlet syndrome. Your healthcare 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 healthcare provider may also order specific tests to help make the diagnosis. These might include:

  • 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 identify abnormalities of bone (like an extra rib)
  • Computed tomography (CT), if the healthcare provider needs to see more detail
  • CT angiography, to get more information about blood flow through your arm

Seeing a specialist is sometimes necessary to diagnose thoracic outlet syndrome. Thoracic outlet syndrome is often more difficult to diagnose than other more common disorders of the shoulder.

Possible treatments of thoracic outlet syndrome include:

  • Physical therapy to help strengthen your shoulder muscles, improve your posture, and enlarge the thoracic outlet space
  • Over-the-counter pain medicines to relieve pain and swelling
  • Weight loss, if you are overweight
  • Modification of everyday activities that bring on symptoms

These treatments relieve symptoms in most people. If you still have significant symptoms after trying these treatments, your healthcare provider might recommend surgery. For example, your healthcare provider might remove an extra first rib (if present). Sometimes, healthcare providers release an abnormal muscle in your neck or perform operations on the blood vessels of the neck. The exact kind of surgery will depend on the anatomy of your thoracic outlet. Surgery relieves symptoms in many people.

Healthcare providers do not recommend treatment for people who have an extra rib unless they show signs of thoracic outlet syndrome.

Occasionally, thoracic outlet syndrome 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 (causing a 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 healthcare provider may need to treat this clot using blood thinners or a catheter inserted through an artery. Sometimes, healthcare providers may use surgery to remove the clot instead.

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

Avoid carrying heavy bags over your shoulder, which increases pressure on the thoracic outlet. You should also practice your physical therapy exercises to help keep your shoulder muscles strong. Doing these regularly may help keep your symptoms from returning.

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

Thoracic outlet syndrome refers to a variety of symptoms that happen from a narrowing of your thoracic outlet—the space between your collarbone and your first rib. This can compress arteries, veins, and nerves in the region. It can result from injury, disease, or a problem present from birth.

  • You may have symptoms from nerve compression, like pain, tingling, or weakness in your arm or hand.
  • You may have symptoms from blood vessel compression, like a swollen arm, or an arm that is pale and cool.
  • Most people with thoracic outlet syndrome do not need surgery. Your healthcare provider may prescribe physical therapy, modification of your regular activities, or pain medicines to reduce your symptoms.
  • Some people with thoracic outlet syndrome need surgery.
  • Some people with thoracic outlet syndrome develop blood clots in the veins or arteries of their arm. You might need a medicine and a surgical procedure if this happens.

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 recommended 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.
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