Thoracic Outlet Syndrome

In previous posts, we’ve discussed chronic pain, including how chronic conditions can affect dentists.  Dentists in particular are susceptible to these conditions, as they are constantly required to employ sustained grips on instruments while holding awkward, unnatural positions during dental procedures.  As a result, dentists are prone to developing disorders that cause muscle pain, weakness, and numbness, including thoracic outlet syndrome.  In this post we will examine the symptoms, causes, diagnosis, and treatment of thoracic outlet syndrome.


Thoracic outlet syndrome (TOS) is a group of disorders that occur when blood vessels or nerves in the space between the collarbone and the first rib (thoracic outlet) are compressed. This can result in pain in the shoulder, neck, and arm, as well as numbness in the fingers.

There are different types of TOS, including:

  • Neurogenic (neurological) thoracic outlet syndrome: This form of TOS is characterized by compression of the brachial plexus (a network of nerves that come from the spinal cord and control muscle movements and sensation in the shoulder, arm, and hand).
  • Vascular thoracic outlet syndrome: This form of TOS occurs when one or more of the veins (venous thoracic outlet syndrome) or arteries (arterial thoracic outlet syndrome) under the clavicle are compressed.


TOS symptoms vary, depending on where the compression occurs. When nerves are compressed, symptoms of neurogenic TOS include:

  • Muscle wasting in the fleshy base of the thumb (Gilliatt-Sumner hand)
  • Numbness or tingling in the fingers or arm
  • Muscle pain or aches in the neck, shoulder, or hand
  • Weakened grip

Symptoms of vascular TOS include:

  • Bluish discoloration of the hand or lack of color (pallor) in the hands/fingers due to impaired circulation
  • Arm pain and swelling
  • Blood clot in veins or arteries in the upper area of the body
  • Weak or no pulse in the arm
  • Cold fingers, hands, or arms
  • Numbness or tingling in the fingers
  • Weakness of arm or neck
  • Throbbing lump near the collarbone


TOS is caused by the compression of the nerves or blood vessels in the thoracic outlet, just below the clavicle. The cause of compression can include:

  • Anatomical defects, such as an extra rib or an abnormally tight fibrous band connecting the spine to the rib
  • Poor posture, dropping shoulders, or holding the head in a forward position
  • Trauma, such as a car accident
  • Repetitive activity in the upper extremities
  • Pressure on the joints from obesity or carrying a large amount of weight
  • Pregnancy
  • Heredity


Diagnosing TOS can be difficult, as symptoms can vary greatly and are often subjective.  It is not uncommon for TOS to be misdiagnosed as other conditions, such as carpal tunnel syndrome or cubital tunnel syndrome.  To diagnose TOS, a physician will perform a medical history review and physical examination. The examination will include an evaluation of the thoracic outlet, pulses, range of motion, and coloration in the arm, hand, or fingers.

Provocation tests are often used to rule our other causes of symptoms, and include the Roos Stress Test (also known as the elevated arm stress test), Adsons Test, Wright Test, and Eden Test. In these tests, a physician will ask the patient to move the arms, neck, or shoulder in various positions. Certain maneuvers can produce symptoms and blood vessel “pinching,” resulting in a loss of pulse.

A physician may also require additional screening to confirm the diagnosis of TOS, including:

  • X-rays: to reveal an extra rib or to rule out other conditions in the neck or spine that may be causing symptoms
  • CT Scan: to identify the location of the blood vessel compression
  • MRI: to determine the location and cause of the blood vessel compression or to reveal any congenital defects causing symptoms (such as an extra rib or an abnormally tight fibrous band connecting the spine to the rib)
  • EMG: to evaluate electrical activity of the muscles and identify any nerve damage
  • Nerve Conduction Study: to test and measure the nerves’ ability to send impulses to muscles in different areas of the body and to reveal nerve damage
  • Ultrasound: to see if the individual has vascular TOS or other vascular problems
  • Arteriography and venography: to look at blood flow and see if there is a compressed vein/artery or a blood clot


Treatment of TOS can usually be successful with conservative measures. These treatments include:

  • Physical therapy
  • Anti-inflammatory medications, pain medication, or muscle relaxants
  • Clot-dissolving medication

More severe cases of TOS may require surgery, called thoracic outlet decompression.  This may include removing muscles or the first rib in order to spare injury to the affected nerve and blood vessels from ongoing compression. The surgeon may then repair or replace any damaged blood vessels. Vascular TOS is more likely to require surgery to resolve the symptoms.

These posts are for informative purposes only and should not be used as a substitute for consultation with and diagnosis by a medical professional. If you are experiencing any of the symptoms described above and have yet to consult with a doctor, do not use this resource to self-diagnose. Please contact your doctor immediately and schedule an appointment to be evaluated for your symptoms.


Mayo Clinic,
Medicine Net,
Cleveland Clinic,
Science Direct,
National Organization for Rare Disorders,
John Hopkins Medicine,

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