Thoracic outlet syndrome or TOS is an uncommon group of disorders that cause pain or weakness in the arm and shoulder. The condition can affect anyone but is diagnosed more often in women, those between the ages of 20 and 50, and athletes or people in jobs that require repetitive motions. TOS is not a life-threatening disorder, but it can be difficult to diagnose because the symptoms mimic those of several other conditions.


1. The Definition of Thoracic Outlet Syndrome

The cause of thoracic outlet syndrome is compression, injury, or irritation of the nerves and blood vessels in the upper chest, below the neck, and between the collarbone and the first rib. The thoracic outlet is the rigid, narrow space between the lower neck and upper chest. The subclavian artery, subclavian vein, and brachial plexus nerve bundle pass through this space. If the collarbone slips down and forward, the thoracic outlet narrows and puts pressure on these nerves and blood vessels, leading to the symptoms of TOS.

thoracic outlet syndrome AzmanJaka / Getty Images


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