Thoracic outlet syndrome gets its name from the space (the thoracic outlet) between your collarbone (clavicle) and your first rib. This narrow passageway is crowded with blood vessels, muscles, and nerves. If the shoulder muscles in your chest are not strong enough to hold the collarbone in place, it can slip down and forward, putting pressure on the nerves and blood vessels that lie under it.

Thoracic outlet syndrome can result from injury, disease, or a congenital abnormality. Poor posture and obesity can aggravate the condition, which is more common in women than in men. Psychological changes are often seen in patients with thoracic outlet syndrome. It is not clear whether these changes precede the onset of the syndrome or are the result of it.

Symptoms vary, depending on which structures (nerves or blood vessels) are being compressed:

• Pressure on the blood vessels can reduce the flow of blood to the arms and hands, making them feel cool and tire easily.
• Pressure on the nerves can leave, causing a vague, aching pain in the neck, shoulder, arm, or hand.
• Overhead activities are particularly difficult.

Your doctor will ask you about the history of your symptoms, give you a physical examination, and try to reproduce your symptoms through a series of tests. There may be a depression in the shoulder or a swelling or discoloration in the arm. Range of motion may also be limited.

X-rays may be recommended; MRI (magnetic resonance imaging), nerve conduction velocity tests, or ultrasound may be used to rule out other possible causes for the symptoms.

Your doctor may order special blood circulation tests and electrodiagnostic tests to aid in making the diagnosis of thoracic outlet syndrome.

The treatment for thoracic outlet syndrome is conservative, and usually does not involve surgery.

• Physical therapy can help strengthen the muscles surrounding the shoulder so that they are better able to support the collarbone.
• Postural exercises can help you stand and sit straighter, which lessens the pressure on the nerves and blood vessels.
• Nonsteroidal anti-inflammatory drugs, such as aspirin or ibuprofen, can ease the pain.
• If you are overweight, your physician may recommend that a weight loss program.
• You may need to change your workstation and avoid strenuous activities.
• In rare instances, surgery may be recommended if conservative treatment fails. The surgery involves dividing a muscle in the neck and removing a portion of the first rib.

If you have symptoms of thoracic outlet syndrome, avoid carrying heavy bags over your shoulder because this depresses the collarbone and increases pressure on the thoracic outlet. You could also do some simple exercises to keep your shoulder muscles strong. Here are four that you can try; 10 repetitions of each exercise should be done twice daily:

• Corner Stretch - Stand in a corner (about 1 foot from the corner) with your hands at shoulder height, one on each wall. Lean into the corner until you feel a gentle stretch across your chest. Hold for 5 seconds.
• Neck Stretch - Put your left hand on your head, and your right hand behind your back. Pull your head toward your left shoulder until you feel a gentle stretch on the right side of your neck. Hold for 5 seconds. Switch hand positions and repeat the exercise in the opposite direction.
• Shoulder Rolls - Shrug your shoulders up, back, and then down in a circular motion.
• Neck Retraction - Pull your head straight back, keeping your jaw level. Hold for 5 seconds.

As with any exercise program, if any of these exercise cause pain, stop immediately!