Thoracic outlet syndrome (TOS) is a set of symptoms in the shoulder, arm, or hand. It occurs from a narrowing of the thoracic outlet. This is the space between your collarbone and your first rib. It can result from injury, disease, or a problem present from birth. Thoracic outlet syndrome is not common. It can occur in people of any age. Treatment for thoracic outlet syndrome depends on whether the nerves, arteries, or veins are compressed.

Treatments for thoracic outlet syndrome may be nonsurgical or surgical, and may include:

• Physical therapy to help strengthen shoulder muscles, improve posture, and enlarge the thoracic outlet space.
• Over-the-counter pain medicine to relieve pain and swelling.
• Loss of excess weight.
• Changes to daily activities that bring on symptoms.
• Botulinum toxin shots (injections).
• Surgical decompression, which may be removing a part of a muscle (anterior scalene), the first rib, or a fibrous band.
• Removing blood clots if veins become blocked.

If the brachial plexus is pinched because of TOS (neurogenic TOS), you can have weakness in the hand and wrist. You may also have numbness in the small finger. In cases of TOS that pinch the veins, a blood clot can form in a vein in your arm. This blocks blood flow and may make your arm very swollen. The clot may also move to the lungs and cause a pulmonary embolism. This is a blood clot in an artery in your lung. Or a clot can move somewhere else in your body. You may need to take blood-thinner medicine to prevent clotting. You may need a procedure to remove the clot using a thin tube (catheter) inserted through a vein.

A blood clot may also form in one of the arteries of your arm. This may cause a sudden decrease in blood flow to your arm. The clot may be treated with blood thinners or a catheter inserted through an artery. In some cases, surgery may be done to remove the clot.

There are things you can do to help prevent symptoms. Don't put heavy bags over your shoulder. This increases pressure on the thoracic outlet. Also, practice your physical therapy exercises. This will help keep your shoulder muscles strong.

You may have a poor response to nonsurgical treatment and a good response to Botulinum toxin shots. In that case, you may be a good candidate for surgical decompression.

Contact your doctor right away if you have:

• An arm or hand that is suddenly cool, lighter in color, or swollen.
• Sudden weakness of your hand.
• Symptoms that don't get better with therapy.