Thoracic Outlet Syndrome

Thoracic outlet syndrome (TOS) consists of a group of distinct disorders that affect the nerves in the brachial plexus (nerves that pass into the arms from the neck) and various nerves and blood vessels between the base of the neck and axilla (armpit). For the most part, these disorders have very little in common except the site of occurrence. The disorders are complex, somewhat confusing, and poorly defined, each with various signs and symptoms of the upper limb.

True neurologic TOS is the only type with a clear definition that most scientists agree upon. The disorder is rare, typically painless, and caused by congenital anomalies (unusual anatomic features present at birth). It generally occurs in middle-aged women and almost always on one side of the body. Symptoms include weakness and wasting of hand muscles, and numbness in the hand.

Disputed TOS, also called common or non-specific TOS, is a highly controversial disorder. Some doctors do not believe it exists while others say it is very common. Because of this controversy, the disorder is referred to as “disputed TOS.” Many scientists believe disputed TOS is caused by injury to the nerves in the brachial plexus. The most prominent symptom of the disorder is pain. Other symptoms include weakness and fatigue.

Arterial TOS occurs on one side of the body. It affects patients of both genders and at any age but often occurs in young people. Like true neurologic TOS, arterial TOS is rare and is caused by a congenital anomaly. Symptoms can include sensitivity to cold in the hands and fingers, numbness or pain in the fingers, and finger ulcers (sores) or severe limb ischemia (inadequate blood circulation).

Venous TOS is also a rare disorder that affects men and women equally. The exact cause of this type of TOS is unknown. It often develops suddenly, frequently following unusual, prolonged limb exertion.

Traumatic TOS may be caused by traumatic or repetitive activities such as a motor vehicle accident or hyperextension injury (for example, after a person overextends an arm during exercise or while reaching for an object). Pain is the most common symptom of this TOS, and often occurs with tenderness. Paresthesias (an abnormal burning or prickling sensation generally felt in the hands, arms, legs, or feet), sensory loss, and weakness also occur. Certain body postures may exacerbate symptoms of the disorder.

Article text based on the Wikipedia, licensed under the GFDL. See “Thoracic outlet syndrome” at

Thoracic Outlet Syndrome Links

American TOS AssociationProviding Thoracic Outlet Syndrome information, advocacy, communication and future research, bringing hope to thousands of forgotten patients, and giving support to physicians who take on this difficult condition.eMedicine: Thoracic Outlet SyndromeA detailed article discussing Thoracic Outlet Syndrome diagnosis and treatment, from a physician’s point of view.NINDS Thoracic Outlet Syndrome Information PageAn informational page from the National Institute of Neurological Disorders and Stroke.Physical Therapy Corner: Thoracic Outlet SyndromeInformation about the diagnosis and treatment of Thoracic Outlet Syndrome, with illustrations and photos.Welcome to Thoracic Outlet SyndromeA web site explaining the diagnosis of Thoracic Outlet Syndrome including, but not limited to pain, chest pain, entrapment neuropathies, shoulder pain, neck pain, vascular diagnosis, peripheral vascular disease, reflex sympathetic dystrophy, upper extremity pain, headaches, angina, impotence and carpal tunnel syndrome.