What Causes Thoracic Outlet Syndrome (TOS)?
Symptoms are predominately neurologic in origin due to compression of the brachial plexus. This nerve is made up of many nerve fibers that originate from several levels of the spinal cord in the area of the neck. These nerves combine to form one large nerve trunk just before it passes over the upper most rib in the chest cage. Ninety per cent of all symptoms of TOS arise from nerve compression. The other symptoms can arise from compression of the subclavian artery or vein as they pass in the same area. There are several muscles attached to the first rib. There are also a number of ligaments in the area. Compression symptoms can arise from any these structures as they impinge upon the free passage of the blood vessels or nerves. What are the Symptoms of TOS? As stated, most of the symptoms of TOS are related to nerve compression. This causes numbness, weakness, odd sensations in the shoulder or arm especially when the arm is held above the head or rotated outward. Common activities such
