Thoracic outlet syndrome consists of symptoms caused when nerves or blood vessels in the brachial plexus are compressed (squeezed). The brachial plexus is the space between the collarbone and first rib, where nerves and blood vessels pass into the arms from the neck. Symptoms depend on whether the nerves, artery, or vein is compressed. The artery takes blood away from the heart. The vein takes blood back to the heart. The nerve is affected most, 95% of the time. The syndrome is more common in women 20 to 50 years old. It’s rare in people younger than 20.
Causes include an abnormal muscle position, an abnormal congenital rib in the neck, blood clots, and abnormalities of the first rib. Shoulder and collarbone problems from injuries, trauma, or carrying heavy backpacks for long periods can cause it. The syndrome isn’t passed from parents to children and isn’t contagious.
Symptoms include pain in the shoulder, arm, or hand, or in all three. Hand pain is often worst in the fourth and fifth fingers. Fingers can get numb and tingle, and the grip can get weak. Pain gets worse with use of the arm, and the arm often gets tired.
The artery or vein is rarely affected alone. Artery compression causes a pale skin color, coolness, and numbness of the arm. Vein compression causes swelling and pain of the arm.
The health care provider makes a diagnosis with the medical history, physical examination, blood tests, X-rays, and special imaging scans. Scans may include chest computed tomography (CT), mainly to rule out other disorders. Arteriography or venography may be done. In arteriography, dye is injected into the artery. In venography, dye is injected into the vein.
Treatment aims to fix abnormalities in posture that may contribute to compression and to develop an exercise program to strengthen shoulder muscles. Treatment of nerve compression is usually conservative. Surgery may be done for vascular or major nerve difficulties, but it’s used for only a few people. In certain cases (e.g., compression of the vein with a blood clot), the health care provider may suggest using a blood thinner called warfarin to prevent more clots.
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