A generalized term that describes a group of disorders in which there is compression of subclavian artery and vein, the brachial plexus or both. The brachial plexus is a bundle of nerves that runs from the neck through the space between your your first rib and your clavicle, the thoracic outlet, to the arm. Thoracic outlet syndrome (TOS) may be classified neurogenic, arterial, or venous in nature. Symptoms include: numbness, tingling, swelling, coldness, feeling of heaviness, and cyanosis of the upper extremity. Symptoms may also include pain in the neck and shoulder.

Image provided by Wikipedia