ABSTRACT
Thoracic outlet syndrome comprises several situations entailing compression of vascular structures and nerves. The structures that pass through the thoracic outlet are the subclavian vein, the subclavian artery, and, coming from the brachial plexus, the bundle of nerves that supply the upper extremity. Although the brachial plexus originates in the cervical spine, the nerves travel through muscle bundles that insert on top of the first rib and course down into the arm. When compression of the vein occurs suddenly as the result of an unusual physical movement of the arms, the person develops acute damage of the subclavian vein at the thoracic outlet. The endothelium is injured, leading to immediate thrombosis of the vein at that level and extending rapidly toward the arm distally. When subclavian vein stenosis, compression, or thrombosis is suspected, the test of choice is the duplex ultrasound exam.
