Thoracic outlet syndrome refers to a group of conditions that develop when the blood vessels or nerves in the thoracic outlet become compressed.

The thoracic outlet is the narrow space between your collarbone and first rib. Blood vessels, nerves, and muscles that extend from the back to the arms pass through this area. If the space in the thoracic outlet is too narrow, these structures can become compressed.

The increased pressure on the blood vessels and nerves may cause pain in your shoulders, neck, and arms. It can also cause numbness or tingling in your hands.

The cause of thoracic outlet syndrome isn’t always known. However, it may be triggered by physical trauma from a car accident, repetitive movements, or certain structural abnormalities.

Treatment for thoracic outlet syndrome typically consists of physical therapy and medication. Surgery may be needed if symptoms don’t improve after initial treatment.

The symptoms that you experience as a result of thoracic outlet syndrome will depend on whether the nerves or the blood vessels are affected.

Compressed nerves can cause:

  • pain in parts of the neck, shoulder, arm, or hand
  • numbness in the forearm and fingers
  • weakness of the hand

Compressed blood vessels can cause:

  • swelling of the arm
  • redness of the arm
  • hands or arms that feel cold to the touch
  • hands or arms that become easily fatigued

You may also find it difficult to lift objects above your head. You might also have a limited range of motion in your shoulders and arms.

Thoracic outlet syndrome usually occurs when the thoracic outlet becomes narrowed and compresses the nerves and blood vessels. The cause of this compression isn’t always known. However, it may develop as a result of the following conditions:

An extra rib

Some people are born with an extra rib above their first rib. This reduces the size of their thoracic outlet and compresses nerves and blood vessels.

Poor posture and obesity

People who don’t stand up straight or who have excess abdominal fat may have increased pressure on their joints. This can cause a narrowing of the thoracic outlet.


Car accidents and other traumatic injuries can compress the thoracic outlet as well as the vessels and nerves in this area.

Overuse of the shoulders and arms

Repetitive activities, such as working at a computer or lifting heavy objects above the head, can cause damage to the tissues in the thoracic outlet. Over time, the size of the thoracic outlet may shrink, placing pressure on the vessels and nerves.

Your doctor will first perform a physical exam and review your symptoms and medical history. During the exam, your doctor may use what are called “provocation tests” to evaluate your condition.

These tests are meant to reproduce your symptoms so your doctor can make a diagnosis more easily. Your doctor will ask you to move your neck, shoulders, and arms in different positions.

For example, they may ask you to put your hands over your head or to open and close your hands for 3 minutes. If your symptoms develop during provocation tests, then you likely have thoracic outlet syndrome.

To confirm the diagnosis, your doctor may order additional tests, including the following:

  • An X-ray of the thoracic outlet can reveal whether you have an extra rib. It may also rule out other conditions that could be causing your symptoms.
  • An MRI uses powerful magnets and radio waves to create clear, detailed images of the thoracic outlet. The pictures can help determine the location and cause of the compression. They may also show certain structural abnormalities that could be causing your symptoms.
  • Electromyography allows your doctor to see how well the muscles and nerves in the thoracic outlet are working. During this test, an electrode is inserted through your skin into various muscles. It evaluates the electrical activity of your muscles when at rest and when contracted.
  • A nerve conduction study uses a low amount of electrical current to measure how quickly your nerves send impulses to various muscles throughout the body. It can determine whether you have nerve damage.

The goal of treatment for thoracic outlet syndrome is to ease symptoms and pain. The specific type of treatment used may vary depending on the cause and severity of the condition. You and your doctor can discuss which treatment option is best for you.

First-line treatments

Treatment for thoracic outlet syndrome typically starts with the use of medications to help ease your symptoms. Over-the-counter medications, such as naproxen or ibuprofen, may be used to reduce inflammation and pain.

In some cases, your doctor may give you thrombolytic drugs through your veins or arteries to dissolve blood clots in the thoracic outlet. They might also prescribe anticoagulants to prevent blood clots from forming and blocking blood flow.

Physical therapy is also recommended to help strengthen and stretch the shoulder muscles. Strengthening these muscles will improve your range of motion as well as your posture. It will also provide support for the collarbone and muscles surrounding the thoracic outlet.

Over time, physical therapy exercises may take the pressure off the blood vessels and nerves in the affected area.

If you’re overweight, your doctor may recommend a weight-loss program or specific diet to help relieve symptoms. Maintaining a healthy weight is important for reducing pressure on the joints.


You may need surgery if your symptoms don’t improve with medication and physical therapy. Surgery for thoracic outlet syndrome might involve removing an extra rib, removing a section of the first rib, or rerouting blood vessels around the thoracic outlet.

If the vessels in the thoracic outlet are severely narrowed, angioplasty may be used to open them up. During angioplasty, tiny balloons are used to inflate the narrowed vessels.

The outlook for people with thoracic outlet syndrome is typically very good, especially when treatment is received promptly.

In most cases, the symptoms of thoracic outlet syndrome will improve with medication and physical therapy. Surgery also tends to be effective in treating the condition. However, the symptoms may return after surgery for some people.

It may not be possible to prevent thoracic outlet syndrome. If the condition develops, you can take steps to reduce symptoms and to prevent it from recurring. These include:

  • practicing proper posture when sitting or standing
  • taking breaks at work or school to stretch and move around
  • maintaining a healthy weight
  • performing strengthening exercises
  • avoiding activities that make your symptoms worse
  • avoiding lifting heavy objects
  • avoiding carrying heavy bags on the shoulders
  • avoiding making repetitive movements

It’s important to contact your doctor as soon as you notice a recurrence of symptoms. Getting prompt treatment is critical for preventing complications. When the condition goes untreated, thoracic outlet syndrome can eventually lead to permanent neurological damage.