Thoracic Outlet Syndrome is a group of disorders that occur when certain blood vessels or nerves are compressed.

Between the rib cage and the collarbone (clavicle) is a space where the main blood vessels and nerves pass from the neck and the chest into the arm.

This space is called the thoracic outlet. From this outlet, the nerves and blood vessels leave the neck between two muscles (scalene muscles).

If pressure is put on the nerves or blood vessels as they go through the thoracic outlet, a cluster of symptoms can occur. (This is called a syndrome.)


Symptoms of Thoracic Outlet Syndrome

The symptoms of thoracic outlet syndrome vary between individuals depending on where the pressure is. They also can vary in how intense the symptoms are. Thoracic outlet syndrome usually affects the arm or hand with a combination of:

  • Coldness in the upper arm or chest
  • Fatigue
  • Numbness
  • Pain
  • Swelling
  • Tingling
  • Weakness
Risk Factors

Causes and Risk Factors for Thoracic Outlet Syndrome

The most common cause of thoracic outlet syndrome is pressure on the nerves or blood vessels that go to the arms. Sometimes this pressure is caused by an extra first rib or an old fracture of the clavicle, which makes the space of the thoracic outlet narrower.

Weak shoulder muscles can cause the collarbone to slip down and forward, putting pressure on the nerves and blood vessels that lie under it. Poor posture or obesity can also contribute to thoracic outlet syndrome. Pressure may also be caused by repeatedly doing activities that involve raising or holding the arms overhead. Accidents or injuries can cause the syndrome as well. In some cases, it may not be possible to identify what has caused the syndrome.


Diagnosing Thoracic Outlet Syndrome

This condition can have symptoms that are much like those of carpal tunnel syndrome, a herniated disk in the neck or even bursitis of the shoulder. This can make thoracic outlet syndrome difficult to diagnose.

Your doctor generally will examine you and ask about the history of your symptoms. He or she may try to recreate your symptoms through a series of tests used to diagnose thoracic outlet syndrome. Some of the things that your doctor may do include:

  • Look for a depression in your shoulder or any swelling or discoloration in your arm
  • Check the range of motion you have in your shoulder
  • Order X-rays to check for any abnormalities of your rib cage or collarbone
  • Magnetic resonance imaging (MRI)
  • Nerve conduction tests to see how well your nerves are communicating with your muscles
  • Ultrasound, which can help your doctor see how blood is flowing to the affected area
  • Special blood circulation tests

Treating Thoracic Outlet Syndrome

Treatment of this condition vary depending on the cause of thoracic outlet syndrome and the nature and intensity of the symptoms. Treatment options include:

  • Adjusting activities
  • Environmental assessments
  • Exercises
  • Good posture and overall conditioning
  • Non-steroidal anti-inflammatory drugs
  • Proper clothing
  • Surgery
  • Weight loss

Doctors Who Treat Thoracic Outlet Syndrome