What is Thoracic Outlet Syndrome?
What is Thoracic Outlet Syndrome?

Thoracic outlet syndrome is a pain syndrome of the upper extremities. Doctors use the abbreviation ‘TOS’ instead of the full name of the disease, ‘Thoracic Outlet Syndrome.’ TOS patients suffer pain, tingling, numbness, weakness, or abnormal blood flow in one or both upper extremities. TOS can range from an emergent surgical condition to a progressive, chronic pain syndrome that alters the lives of TOS patients.
Three vital structures pass from the neck and chest to reach each upper extremity. When compression of these vital structures causes symptoms, TOS is present.
What are the three types of TOS?
Anatomy of the Thoracic Outlet
The anatomy of the thoracic outlet appears incredibly complex. Besides the native anatomy, a number of anatomic variants and anomalies create more complexity. These variants can compress the nerves, artery or veins, resulting in TOS. Moreover, motion of the arms causes complex changes in the anatomic tunnels of the thoracic outlet. When you understand the anatomy of the thoracic outlet, you have taken the first step in understanding thoracic outlet syndrome.
What causes TOS?

The nerves, artery and vein must be free to pass through the thoracic outlet. However, anatomic variants, acquired abnormalities, and abnormal arm motion may cause compression of these vital structures. In that case, patients may experience the symptoms of thoracic outlet syndrome. People with neck injuries, occupational injuries or overuse, and overhead athletes are all at risk for developing thoracic outlet syndrome.
History of TOS
Like many other scientific pursuits, the history of TOS takes many twists and turns. In essence, The history revolves around human nature, curiosity and discovery. Here you can enjoy a wild and fascinating ride of dead ends and discoveries, egos and errors, personalities and politics. Learn about the history of TOS, starting from a simple English housemaid to modern robotic surgeons.