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.)
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
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.
Slightly more women than men develop 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 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
Treatment of this condition will vary depending on the cause of thoracic outlet syndrome and the nature and intensity of the symptoms. Treatment options include:
- Adjusting activities to reduce the amount of time that arms are used in an outstretched or overhead position. This may be done by taking breaks more often, changing positions frequently and stretching. If you have symptoms, you may want to avoid carrying heavy bags over your shoulder because this pulls the collarbone done and puts more pressure on the thoracic outlet.
- Environmental assessments. This involves having a specialist evaluate your work place or home to make sure that you are working with proper body alignment, postures and work-related furniture to reduce the stress on your body.
- Exercises, which may be taught by a physical or occupational therapist. These can help strengthen muscles that support your collarbone and improve posture.
- Good posture and overall conditioning. This can help maintain a balance between muscles. This also helps you stand, sit and move straighter, which puts less pressure on the nerves and blood vessels.
- Non-steroidal anti-inflammatory drugs like aspirin or ibuprofen, which can ease pain and swelling
- Proper clothing. Women with large or heavily hanging breasts may benefit from wearing a strapless long-line bra.
- Surgery. This is usually done as a last resort in situations where there is an obvious cause such as an extra rib or broken collarbone. Surgery involves dividing a muscle in the neck and removing a portion of the first rib.
- Weight loss, if obesity is an issue
