Thoracic Outlet Syndrome (TOS)

Thoracic outlet syndrome (TOS) is a disorder that may compress the blood vessels or nerves in the upper chest region. This area — called the thoracic outlet — is behind and below the collarbone opposite the first rib.

At UPMC, we take a team approach to quickly and correctly diagnosing TOS. Then, we'll create a treatment plan that's right for you.

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On this page

• What Is Thoracic Outlet Syndrome (TOS)?
• What Are the Symptoms of TOS?
• How Do You Diagnose TOS?
• How Do You Treat TOS?

What Is Thoracic Outlet Syndrome (TOS)?

Thoracic outlet syndrome (TOS) is a group of disorders that puts pressure on the arteries, veins, or nerves in the upper chest.

How common is TOS?

TOS is a rare condition that can be challenging to diagnose. Researchers estimate that it affects between 3 and 80 out of 1,000 people, depending on the type of TOS.

What are the types of TOS?

There are three types of TOS. Symptoms help doctors determine the type of TOS you have.

Arterial thoracic outlet syndrome (ATOS)

In ATOS, an artery in the thoracic outlet compresses, narrows, or dilates.

An extra rib at the top of the rib cage or an abnormal first rib may cause this type of TOS.

Complications of ATOS can include:

• Arterial aneurysm, which is a bulging, weakened area in the artery.
• Blood clots that form in the aneurysm.
• Blockage of blood flow to the hand and fingers.

Venous thoracic outlet syndrome (VTOS)

In VTOS, a vein in the thoracic outlet becomes compressed and damaged. The most common cause is repetitive, strenuous shoulder and arm use.

Complications of VTOS can include:

• Arm swelling.
• Blood clots that form in the damaged vein.
• Pulmonary embolism.

Neurogenic thoracic outlet syndrome (NTOS)

In NTOS, the brachial plexus — the bundle of nerves in the thoracic outlet — compresses, often from:

• A prior injury.
• Repetitive forces from exertional movements.
• Trauma.

NTOS complications can include:

• Neck, arm, or shoulder weakness.
• Neck, arm, shoulder, or back pain that disrupts sleep, work, and daily activities.
• Nerve damage.

What causes TOS?

Compressed blood vessels or nerves in the tight corridor of the thoracic outlet get irritated and can cause TOS. Causes of compression may be:

• Bony and soft tissue abnormalities, such as an extra rib or an old collarbone injury.
• Heavy weightlifting.
• Injury to the neck or back, such as whiplash.
• Playing sports that involve repetitive arm or shoulder movement, such as golf, baseball, swimming, volleyball, tennis, etc.
• Poor posture.
• Repetition injuries from carrying heavy shoulder loads.
• Tumors or enlarged lymph nodes in the upper chest or armpit.

What are TOS risk factors and complications?

TOS risk factors

TOS happens to people of all ages and genders, but it is more common in young women.

Factors that can increase your risk of TOS include:

• Having poor thoracic posture.
• Playing a sport with repetitive arm motion — like baseball, volleyball, swimming, or tennis.
• Prior cervical spine or neck trauma.
• Stress from repetitive tasks.

Complications of TOS

TOS can occur on either side of the body but most often affects your dominant hand's side because of constant use.

Complications vary depending on the type of TOS you have.

A blood clot may break apart, and smaller pieces — called emboli — can move down the arm. A blood clot can block blood flow to the hand, causing:

• Coolness.
• Discoloration.
• Numbness.
• Pain.

If this occurs, it's vital to restore blood flow to the hand quickly to prevent permanent damage.

How can I prevent TOS?

You may not be able to control all of your risk factors for TOS, such as having a traumatic injury or an extra rib. However, you can take steps to ensure you have proper posture — especially when lifting heavy items or playing sports that involve repetitive arm motions.

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 What Are the Signs and Symptoms of TOS?

TOS most often causes symptoms in the upper body, such as the:

• Arm
• Back
• Hand
• Neck

Symptoms vary based on the type of TOS.

Symptoms of ATOS

Symptoms of ATOS include:

• Cramping when using the arm.
• Pain, coldness, and paleness or change of color in the hand.

Symptoms of VTOS

Symptoms of VTOS include:

• Arm pain.
• Dilated chest wall veins.
• Heaviness or fullness.
• Swelling and dark color in the arm.

Symptoms of NTOS

Symptoms of NTOS include:

• A tired feeling in the arm.
• Headaches at the back of the head.
• Neck pain.
• Pain, numbness, tingling, or weakness in the arm and hand.
• Pain that starts in the shoulder and moves down the arm into the fingertips.

When should I see a doctor about my TOS symptoms?

If you have TOS symptoms that don’t go away, you should schedule an appointment with your doctor.

Should I go to the ER for thoracic outlet syndrome?

If you have emergency symptoms, such as blockage of blood flow to your hand, you should go to your nearest hospital emergency room.

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How Do You Diagnose TOS?

In most cases, your doctor can diagnose TOS during a physical exam. You may need other tests to confirm the diagnosis.

What to expect during your visit

To confirm a diagnosis of TOS, your doctor will start by:

• Asking about your TOS symptoms.
• Asking you to perform movements to reproduce the symptoms.
• Performing a thorough exam.
• Reviewing your medical history.

Tests to diagnose TOS

Your doctor may order heart imaging and other tests, including:

• Arteriography or venography. X-ray exams that use contrast dye to show blood flow through blood vessels to view your arteries or veins.
• Chest x-ray – A chest x-ray is a diagnostic test that uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
• Computed tomography (CT) scan – This test uses a ring of multiple x-rays to create detailed 3D images of your blood vessels.
• Magnetic resonance imaging (MRI) – MRI uses a large magnetic field, radio waves, and computers to create detailed images of your blood vessels.
• Nerve conduction velocity test – Measures how fast an electrical impulse moves through a nerve.
• Ultrasound – This test uses sound waves to show how well your blood flows through your blood vessels.

TOS prognosis

Early diagnosis and treatment of TOS are key to reducing the risk of complications and delivering a successful treatment outcome. Your prognosis will depend on the type of TOS you have, as well as the severity of your condition.

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How Do You Treat TOS?

Vascular surgeons at UPMC offer a range of treatments for arterial, venous, and neurogenic TOS.

Based on your TOS type, we'll recommend a treatment plan that meets your needs. Treatments by type of TOS include:

Treatment for ATOS

Surgery for ATOS

Your surgeon may operate to:

• Repair your artery, if needed.
• Expand your thoracic outlet.
• Remove the first rib or extra rib above it, if present.

Treatment for VTOS

Medication for VTOS

Your doctor may prescribe blood-thinning medications to prevent blood clots from forming.

Minimally invasive catheter-based treatments for VTOS

• Thrombolysis. Your doctor will use a catheter to send clot-busting drugs directly into your vein to break up a blood clot.
• Venoplasty. Your doctor will thread a balloon-tipped catheter into your vein and expand the balloon to open up the vein.

Surgery for VTOS

Your vascular surgeon may operate to:

• Expand your thoracic outlet.
• Remove the blood clot.
• Remove your abnormal rib.
• Repair or replace your damaged vein.

Treatment for NTOS

Physical therapy for NTOS

Your doctor may recommend physical therapy to:

• Assess your work site and suggest changes.
• Develop an exercise program that doesn’t worsen symptoms.
• Help you avoid motions that cause symptoms.
• Improve body posture and conditioning.
• Stretch the affected area and improve your range of motion and strength.

Medication to treat NTOS

Your doctor may prescribe nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin or ibuprofen, or other medications to manage pain.

Surgery for NTOS

Doctors may recommend surgery if your symptoms do not respond to physical therapy or medication. Your surgeon may:

• Clean the scar tissue around your nerves.
• Expand your thoracic outlet.
• Remove your first rib.

How effective is treatment?

When diagnosed early, TOS treatment effectively manages symptoms and improves quality of life.

Will thoracic outlet syndrome go away?

Depending on the cause, TOS symptoms may go away without treatment or with nonsurgical care. However, if your symptoms come and go or don’t get better, it’s important to see your doctor. Some types of TOS will not go away without minimally invasive or surgical care.

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Why Choose UPMC for TOS Care?

When you choose UPMC for TOS care, you will benefit from:

• Our coordinated TOS treatment approach. Our team of endovascular and vascular surgeons works closely with other specialists to ensure complete care.
• Our vascular surgeons. As specialists in the surgical treatment of TOS, our vascular surgeons have the skills and expertise required to deliver outstanding outcomes.
• Our experience. Our experts perform hundreds of vascular procedures every year. UPMC is also a major referral center for people with TOS or other complicated vascular conditions.

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By UPMC Editorial Staff. Last reviewed on 2024-10-01.