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from the American Academy of Orthopaedic Surgeons

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Thoracic Outlet Syndrome

Thoracic outlet syndrome is a term used for several rare and different conditions that can occur when nerves and/or blood vessels in the thoracic outlet are compressed (squeezed) or irritated.

The thoracic outlet is the space between your collarbone (clavicle) and your first rib. This narrow passageway is crowded with blood vessels, muscles, and nerves. If the shoulder muscles in your chest are not strong enough to hold the collarbone in place, it can slip down and forward, putting pressure on the nerves and blood vessels that lie under it. This causes a variety of symptoms which together are known as thoracic outlet syndrome.

Anatomy illustration, including the location of the thoracic outlet
The thoracic outlet is the space between your collarbone and first rib.
Reproduced and modified from JF Sarwark, ed: Essentials of Musculoskeletal Care, ed 4. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2010. 


Thoracic outlet syndrome can result from:

  • An injury
  • A disease
  • A congenital problem (something you are born with), such as an abnormal first rib

The condition is more common in women than in men, and poor posture and obesity can aggravate the condition.

Psychological changes are often seen in patients with thoracic outlet syndrome. It is not clear whether these changes are a cause or result of the syndrome.


Patients with thoracic outlet syndrome often experience a variety of symptoms. Which symptoms you have often depends on which nerves or blood vessels are compressed. Symptoms from nerve compression are much more common than symptoms from blood vessel compression; they are also easier to diagnose.

The following are common signs of thoracic outlet syndrome:

  • Pressure on the nerves (brachial plexus) may cause:
    • A vague, aching pain in the neck, shoulder, arm, or hand
    • Pain, numbness, or tingling on the inside of the forearm and the fourth and fifth fingers of the hand
    • Weakness that may make your hand clumsy
  • Pressure on the blood vessels can reduce the flow of blood out of your arm, resulting in swelling, redness, or other discoloration of your arm. Less commonly, pressure can reduce the blood flow into your arm and hand, making them feel cool and easily fatigued (tired).
  • Overhead activities are particularly difficult because they worsen both types of compression as the rib, collarbone, and/or shoulder blade compress the nerves and blood vessels.
  • Your range of motion may be limited.

Doctor Examination

Diagnosis of this condition can be more complicated than diagnosis of other more common shoulder conditions because there may be many symptoms to explain. Your doctor's evaluation will include an extensive medical history, physical examination, and diagnostic testing.

Medical History and Physical Examination

Your doctor will:

  • Ask you about the history of your symptoms
  • Perform a thorough physical examination
  • Try to reproduce your symptoms by examining your arm and hand in several positions


Elevated arm stress test. Doctors often use the elevated arm stress test to help them identify thoracic outlet syndrome. Your doctor will have you raise your arms over your head, then open and close your fists for approximately 3 minutes. If this reproduces your symptoms, it is possible that you have thoracic outlet syndrome. However, people who do not have thoracic outlet syndrome may sometimes have a positive test. 

Illustration of elevated arm stress test
Elevated arm stress test.
Reproduced from JF Sarwark, ed: Essentials of Musculoskeletal Care, ed 4. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2010. 

Imaging tests. To better see and evaluate the bones, muscles, tendons, and blood vessels, your doctor may order imaging tests. These may include:

  • X-rays
  • Computed tomography (CT) scans
  • Magnetic resonance imaging (MRI) scans
  • Ultrasound

Additional tests. Your doctor may order special blood circulation tests and nerve conduction tests to help make the diagnosis.

Often, there is not a clear and obvious way to diagnose thoracic outlet syndrome. In some cases, your doctor will perform many tests to rule out other conditions with similar symptoms, such as pinched nerves in your neck or blood clots. 

In some health care institutions, thoracic outlet syndrome is diagnosed and treated by a multidisciplinary team that includes an orthopaedic surgeon, a physical medicine and rehabilitation specialist (PM&R specialist, or physiatrist), physical therapists, a peripheral nerve surgeon, and/or a vascular surgeon.


Treatment for thoracic outlet syndrome usually does not include surgery.

Nonsurgical Treatment

Physical therapy.

  • Exercises can help strengthen the muscles surrounding the shoulder so that they are better able to support the collarbone.
  • Postural exercises can help you stand and sit straighter, which lessens the pressure on the nerves and blood vessels.

Nonsteroidal anti-inflammatory drugs (NSAIDs). Drugs like naproxen and ibuprofen can ease the pain and reduce swelling.

Weight loss. If you are overweight, your doctor may recommend that you begin a weight loss program. Being overweight can stress the shoulder muscles that support your collarbone.

Lifestyle changes. You may need to:

  • Change your workstation layout
  • Avoid strenuous activities
  • Modify everyday activities that aggravate your symptoms

Surgical Treatment

If nonsurgical treatment does not relieve your symptoms, your doctor may offer surgery.

Surgery for thoracic outlet syndrome may involve:

  • Removing a portion of an abnormal first rib
  • Releasing a muscle that joins the neck and chest
  • Sometimes both of the above


If you have symptoms of thoracic outlet syndrome, avoid carrying heavy bags over your shoulder because this depresses (pushes down on) the collarbone and increases pressure on the important structures in the thoracic outlet.

You should also do some simple exercises to keep your shoulder muscles strong. Here are four that you can try — do 10 repetitions of each exercise twice (2 times) daily:

  • Corner Stretch - Stand in a corner (about 1 foot from the corner) with your hands at shoulder height, one on each wall. Lean into the corner until you feel a gentle stretch across your chest. Hold for 5 seconds.
corner stretch for thoracic outlet syndrome

Corner stretch. You should feel this stretch in the front of your shoulder, your chest, and upper back.

  • Neck Stretch - Put your left hand on your head, and your right hand behind your back. Pull your head toward your left shoulder until you feel a gentle stretch on the right side of your neck. Hold for 5 seconds. Switch hand positions and repeat the exercise in the opposite direction.
Neck Stretch

Neck stretch.  You should feel a gentle stretch in your neck as you pull.

  • Shoulder Rolls - Shrug your shoulders up, back, and then down in a circular motion.
Shoulder Rolls

Shoulder rolls. Make sure you are standing or sitting up straight when you do this exercise (no slouching). 

  • Neck Retraction - Pull your head straight back, keeping your jaw level (straight). Hold for 5 seconds.
Neck Retraction

Neck retraction. Make sure to keep your jaw straight as you pull your head back (do not drop or raise your jaw).

As with all exercise programs, if any of these movements cause pain, stop immediately.

Last Reviewed

April 2023

Contributed and/or Updated by

William R. Aibinder, MDGeorge S. Athwal, MDDavid L. Glaser, MDBenjamin Widmer, MD

Peer-Reviewed by

Thomas Ward Throckmorton, MD, FAAOSStuart J. Fischer, MDJ. Michael Wiater, MD

AAOS does not endorse any treatments, procedures, products, or physicians referenced herein. This information is provided as an educational service and is not intended to serve as medical advice. Anyone seeking specific orthopaedic advice or assistance should consult his or her orthopaedic surgeon, or locate one in your area through the AAOS Find an Orthopaedist program on this website.