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Thoracic Outlet Syndrome

Medically reviewed by Last updated on Oct 31, 2022.

What is thoracic outlet syndrome?

Thoracic outlet syndrome (TOS) occurs when nerves or blood vessels are pinched in the thoracic outlet. The thoracic outlet is the area between your collarbone and your first rib. Nerves and blood vessels run through the thoracic outlet as they go from your chest out to your hands.

Thoracic Outlet Syndrome

What are the types of TOS?

  • Neurogenic thoracic outlet syndrome (NTOS) occurs when your nerves are pinched. This is the most common type of TOS. The exact cause of your NTOS may not be known. If the cause is not known, it is called disputed or nonspecific NTOS.
  • Vascular thoracic outlet syndrome occurs when your blood vessels are pinched. Vascular TOS is broken into venous or arterial TOS. Venous TOS occurs when veins are pinched. Arterial TOS is a rare type of TOS that occurs when arteries are pinched.

What causes TOS?

  • Abnormal structure of muscles or ribs can cause TOS. You may have cervical ribs. A cervical rib is an extra rib at the top of your ribcage, close to your collarbone. You may have bands of muscle fibers near your thoracic outlet. The scalene muscles found on each side of your neck may be larger than normal.
  • Injuries , such as a fracture, can cause extra bone or scar tissue to grow where the bone heals. A growth on your collarbone, top rib, or neck can also cause TOS.
  • Repeated movements can pinch your nerves or blood vessels. Some examples include working on a computer all day or playing a sport such as tennis.
  • Drooping shoulders can cause the space around your thoracic outlet to narrow. Drooping may occur with age or poor posture.

What are the signs and symptoms of TOS?

You may feel symptoms on one side of your body, or on both sides. Signs and symptoms may come and go. They may get worse when your arm is raised above shoulder level. They may also get worse after activity, such as throwing a ball. You may have any of the following:

  • Pain or tingling in your head, neck, shoulder, arm, or hand
  • Numbness in your arm or hand
  • Swelling and aching in your arm or hand
  • A cold, pale, or bluish arm or hand

How is TOS diagnosed?

Your healthcare provider will check your posture. He or she will check your pulse and ask you to move your head, neck, arms, or hands in different positions. Your provider will ask about your symptoms during these movements. He or she will also check the nerves in your arms and hands. You may also need any of the following:

  • Blood tests may be needed to check for other conditions, such as infection.
  • An x-ray of your chest, neck, or shoulders will show cervical ribs or a fracture.
  • An electromyography (EMG) measures the electrical activity of your muscles. Your muscles are tested at rest and during motion. An EMG test also checks the nerves that control your muscles.
  • An MRI is a scan that uses powerful magnets and a computer to take pictures of your muscles, bones, and blood vessels. An MRI may show problems or changes in your thoracic outlet. You may be given dye to help the pictures show up better. Tell the provider if you have ever had an allergic reaction to contrast dye. Do not enter the MRI room with anything metal. Metal can cause serious injury. Tell the provider if you have any metal in or on your body.

How is TOS treated?

  • A physical therapist teaches you exercises to strengthen the muscles in your neck, shoulders, and back. This can help increase the amount of room in the thoracic outlet. These exercises can also help improve your posture and decrease pain.
  • Medicines:
    • Nonsteroidal anti-inflammatory (NSAID) medicine may decrease swelling or pain. This medicine can be bought with or without a doctor's order. NSAIDs can cause stomach bleeding or kidney problems in certain people. If you take blood thinner medicine, always ask your provider if NSAIDs are safe for you. Always read the medicine label and follow the directions on it before using this medicine.
    • Muscle relaxers or other medicines to decrease nerve pain may be needed. Ask your provider for more information about these medicines.
    • Prescription pain medicine may be given to decrease pain. Do not wait until the pain is severe before you take this medicine.
  • Surgery may be needed if other treatments do not work. Providers may cut or remove your scalene muscles or one or more ribs. They may remove the fibrous bands in the thoracic outlet.

How can I help manage my symptoms?

  • Practice correct posture.
  • Do not sleep with your arms above your chest.
  • Avoid activities that involve repeated movements.
  • Do exercises as directed to strengthen and stretch your shoulder and neck muscles.

When should I contact my healthcare provider?

  • You have new pain, numbness, or tingling in your neck, shoulder, arm, or hand.
  • You have a weak grip that is new for you.
  • One hand looks smaller than the other.
  • You have questions or concerns about your condition or care.

When should I seek immediate care?

  • You have severe pain.
  • Your arm or hand feels heavy.
  • Your arm or hand is cold, or looks pale or blue.

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your healthcare providers to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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