Overview

Thoracic outlet syndrome (TOS) is a group of disorders that occur when blood vessels or nerves in the space between your collarbone and your first rib (thoracic outlet) are compressed. This can cause shoulder and neck pain and numbness in your fingers.

Common causes of thoracic outlet syndrome include physical trauma from a car accident, repetitive injuries from job- or sports-related activities, certain anatomical defects (such as having an extra rib), and pregnancy. Sometimes doctors don't know the cause of thoracic outlet syndrome.

Treatment for thoracic outlet syndrome usually involves physical therapy and pain relief measures. Most people improve with these treatments. In some cases, however, your doctor may recommend surgery.

Symptoms

There are three general types of thoracic outlet syndrome:

  • Neurogenic (neurologic) thoracic outlet syndrome. This most common type of thoracic outlet syndrome is characterized by compression of the brachial plexus. The brachial plexus is a network of nerves that come from your spinal cord and control muscle movements and sensation in your shoulder, arm and hand.
  • Venous thoracic outlet syndrome. This type of thoracic outlet syndrome occurs when one or more of the veins under the collarbone (clavicle) are compressed, resulting in blood clots.
  • Arterial thoracic outlet syndrome. This is the least common type of TOS. It occurs when one of the arteries under the collarbone is compressed, resulting in bulging of the artery, also known as an aneurysm.

It's possible to have a mix of the three different types of thoracic outlet syndrome, with multiple parts of the thoracic outlet being compressed.

Thoracic outlet syndrome symptoms can vary depending on the type. When nerves are compressed, signs and symptoms of neurogenic thoracic outlet syndrome include:

  • Numbness or tingling in your arm or fingers
  • Pain or aches in your neck, shoulder, arm or hand
  • Weakening grip

Signs and symptoms of venous thoracic outlet syndrome can include:

  • Discoloration of your hand (bluish color)
  • Arm pain and swelling
  • Blood clot in veins in the upper area of your body
  • Arm fatigue with activity
  • Paleness or abnormal color in one or more fingers or your hand
  • Throbbing lump near your collarbone

Signs and symptoms of arterial thoracic outlet syndrome can include:

  • Cold fingers, hands or arms
  • Hand and arm pain
  • Lack of color (pallor) or bluish discoloration (cyanosis) in one or more of your fingers or your entire hand
  • Weak or no pulse in the affected arm

When to see a doctor

See your doctor if you consistently experience any of the signs and symptoms of thoracic outlet syndrome.

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Causes

Thoracic outlet syndrome is usually caused by compression of the nerves or blood vessels in the thoracic outlet, just under your collarbone (clavicle). The cause of the compression varies and can include:

  • Anatomical defects. Inherited defects that are present at birth (congenital) may include an extra rib located above the first rib (cervical rib) or an abnormally tight fibrous band connecting your spine to your rib.
  • Poor posture. Drooping your shoulders or holding your head in a forward position can cause compression in the thoracic outlet area.
  • Trauma. A traumatic event, such as a car accident, can cause internal changes that then compress the nerves in the thoracic outlet. The onset of symptoms related to a traumatic accident often is delayed.

Risk factors

There are several factors that seem to increase the risk of thoracic outlet syndrome, including:

  • Sex. Females are greater than three times more likely to be diagnosed with thoracic outlet syndrome than are males.
  • Age. Thoracic outlet syndrome may occur at any age but is most commonly diagnosed in adults between the ages of 20 and 50.

Complications

Complications from this condition stem from the type of presentation (neurogenic, venous or arterial). For patients with venous or arterial TOS, it is important to seek urgent medical attention to make the correct diagnosis and implement appropriate treatment. For neurogenic TOS, it is important to seek medical attention with appropriate evaluation and testing.

Prevention

If you're at risk for thoracic outlet compression, avoid repetitive movements and lifting heavy objects. If you're overweight, losing weight may help you prevent or relieve symptoms of thoracic outlet syndrome.

Even if you don't have symptoms of thoracic outlet syndrome, avoid carrying heavy bags over your shoulder, because this can increase pressure on the thoracic outlet. Stretch daily, and perform exercises that keep your shoulder muscles strong.

Daily stretches focusing on the chest, neck and shoulders can help improve shoulder muscle strength and prevent thoracic outlet syndrome.

Thoracic outlet syndrome care at Mayo Clinic

Jan. 04, 2022
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