Skip to main content
Explore URMC
URMC / Encyclopedia / Content

Thoracic Outlet Syndrome

What is Thoracic Outlet Syndrome?

Thoracic Outlet Syndrome (TOS) refers to an ill-defined assortment of disorders originating in the passageway between the neck and chest – called the thoracic outlet. These disorders arise from the crowded nature of the thoracic outlet, which is an expressway for the throat, trachea, major blood vessels and many nerves. TOS commonly shows itself as pain, swelling or a “pins and needles” sensation in the hands, shoulders and arms. Similar discomforts can occur in other parts of the upper body including the chest, neck, head and ears.

At the root of all TOS problems is pressure or compression on nerves or blood vessels passing through the thoracic outlet. The particular nerves and blood vessels compressed are usually the nerves of the branchial plexus and the subclavian artery or vein. Sometimes the pressure is severe enough to cause Raynaud’s Syndrome, in which the fingers turn white when in the cold. Severe TOS also has been known to result in gangrene in the fingers.

The Mechanics of Thoracic Outlet Syndrome

TOS problems occur when blood vessels or nerves passing through the thoracic outlet become squeezed in some way—say, between a rib and an overlying muscle. If an artery comes under pressure, oxygen supplied to the affected part of the body is diminished. A pinched or compressed nerve can trigger numbness, tingling or other sensations at the end of the nerve, which might be in the fingers or in the ear. Except in the more severe cases of abnormality or injury, it’s very likely that removal of the pressure will also remove the troublesome symptom.

Symptoms of Thoracic Outlet Syndrome

Symptoms indicating TOS can include:

  • Numbness, tingling, cold, or weakness in the arms and hands
  • Wwelling or discoloration (blue, white) of the hands and fingers
  • Pain, tiredness, or heaviness in the upper arm
  • cCest pain
  • Headaches
  • “Funny feelings” in the face or ear
  • Dizziness, lightheadedness, or vertigo

Causes of Thoracic Outlet Syndrome

The exact cause of TOS disorders is often unclear. On rare occasions, the cause is found to be an anatomical abnormality or variation, such as a deformed rib or a fibrous band in a muscle, pushing against a nerve or blood vessel. Sometimes an injury that damages or disrupts the thoracic outlet is to blame. Sometimes TOS is traced back to repetitive work tasks. More often than not, however, it is very difficult to pin down the exact cause on the evidence of symptoms alone.

Diagnosing Thoracic Outlet Syndrome

A diagnosis is based on information from the patient’s history, a physical exam, and several tests developed to detect TOS. For example:

  • Subjecting certain nerves to electric stimulus and evaluating reaction
  • Listening for blood flow abnormalities (bruits) with a stethoscope
  • Taking x-rays of the brachial arteries after a radiopaque dye is injected
  • Raising the hands—fingers up, palms out—above the shoulder and checking color
  • Measuring blood flow and volume using a pneumatic cuff on the finger

Doctors are quick to point out, however, that none of these diagnostic procedures can confirm or rule out TOS.

Treating Thoracic Outlet Syndrome

For most people experiencing symptoms of TOS, the recommended treatments are:

  • Physical therapy designed to stretch and open the thoracic outlet
  • Regular exercise
  • Pain medication (analgesics, not opiates)
  • Good posture

Surgery might be recommended for patients who are diagnosed with an anatomical abnormality or variation, or who have experienced a physical injury or trauma that is found to have triggered their TOS.

A Sympathetic Ear
TOS seems to be one of those ailments that is hard to describe, hard to diagnose, and hard to get a doctor to take seriously. You might be called a malingerer, and you might call your own sanity into question. But if you know there’s something wrong, stick to your guns and look for a doctor familiar with TOS.