Thoracic Outlet Syndrome (TOS)

Brain & Nerve
Bone, Muscle, & Joint
Contributed byMaulik P. Purohit MD MPHDec 05, 2018

What are the other Names for this Condition? (Also known as/Synonyms)

  • TOS (Thoracic Outlet Syndrome)

What is Thoracic Outlet Syndrome? (Definition/Background Information)

  • Thoracic Outlet Syndrome (TOS) is an uncommon condition used to illustrate a collection of disorders that describe the compression of nerves or blood vessels in the passageway between the clavicle (collarbone) and first rib (called the thoracic outlet)
  • This leads to weak muscles in the region, pain in the arms/shoulder, and numbness in the fingers

There are three different types of Thoracic Outlet Syndrome, which include:

  • Neurogenic Thoracic Outlet Syndrome: It is the most common type of TOS, which results from the compression of the brachial plexus nerve (located in the shoulder and upper arm, on either side of the body)
  • Vascular Thoracic Outlet Syndrome: This condition is caused by the compression of the subclavian vein (near the first rib) between the clavicle and the first rib
  • Arterial Thoracic Outlet Syndrome: The least common type of TOS, this condition results from the compression of the subclavian artery (near the first rib)

Who gets Thoracic Outlet Syndrome? (Age and Sex Distribution)

Thoracic Outlet Syndrome can affect individuals of any age and sex. The prevalence of this condition depends on the type of Thoracic Outlet Syndrome an individual develops:

  • Neurogenic Thoracic Outlet Syndrome: It is more prevalent in women (than men), and is more likely to develop in young to middle-aged adults
  • Vascular Thoracic Outlet Syndrome: It is more prevalent in men (than women), and is more likely to develop in young adults
  • Arterial Thoracic Outlet Syndrome: This TOS type develops in both men and women equally. It is more prevalent in adults – young, middle-aged, or elderly

What are the Risk Factors for Thoracic Outlet Syndrome? (Predisposing Factors)

Common risk factors associated with Thoracic Outlet Syndrome include:

  • Occupations that involve repetitive lifting, pulling, or carrying of heavy objects, which may compress the passageway between the neck and shoulder and place excessive stress on the nerves
  • Certain sleep disorders
  • Presence of large lymph nodes or tumors in the region (underarm, shoulder, upper chest)
  • A previous injury or fracture (shoulder, rib) that has led to space constriction for the subclavian artery/vein or the brachial plexus nerve
  • Stress, anxiety, depression

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Thoracic Outlet Syndrome? (Etiology)

Thoracic Outlet Syndrome occurs when the nerves and blood vessels in the thoracic outlet space (space between the collar bone and first rib), gets compressed. Some of the causes associated with TOS include:

  • Certain anatomical defects; newborn infants with inherited (bone or tissue related) abnormalities, such as having an extra rib directly above the first rib
  • Poor posture; mainly affecting the neck and shoulders
  • Any significant traumatic event affecting the neck, back, or shoulder (like a whiplash injury), caused by an automobile, motorcycle accident
  • Participation in sports that typically involve a set of repetitive movements (basketball, golf, aquatics, etc.)
  • Occupations requiring frequent lifting or pulling of heavy loads; occupations that involve raising the hands over the head frequently/several times, like dancing, painting
  • Increased pressure on the joints (shoulder) due to obesity
  • During pregnancy, the joints tend to loosen, which may also aggravate an existing mild condition. The indications (signs and symptoms) of TOS may appear during pregnancy
  • Sometimes, the cause of TOS remains unknown/undetermined

What are the Signs and Symptoms of Thoracic Outlet Syndrome?

Symptoms of Thoracic Outlet Syndrome may vary, depending on which nerve or blood vessel is compressed. A majority of the individuals with TOS exhibit symptoms from nerve compression, rather than from constriction of a blood vessel.

Neurogenic Thoracic Outlet Syndrome is described by the compression of the brachial plexus.  The brachial plexus involves a group of nerves that is important for muscle control and sensation within the shoulder, arm, and hand. Most cases involving TOS are neurogenic, the signs and symptoms of which include:

  • Pain, numbness, and tingling sensation, in the fingers and forearm
  • Pain in the neck and shoulders that moves down the arm/hand
  • Weak hand muscles; difficultly gripping objects

Vascular Thoracic Outlet Syndrome involves one or more veins and arteries being compressed. The signs and symptoms include:

  • Discoloration seen in the hand
  • Blood clot under the collarbone
  • Pain and swelling develop due to the blood clot
  • Weakness felt in the arm

How is Thoracic Outlet Syndrome Diagnosed?

  • Diagnostic methods that a physician may use to help diagnose a Thoracic Outlet Syndrome will include a physical examination
  • A thorough physical examination or provocation test is important in examining the arm and hand in several positions, to try and reproduce the individual’s symptoms
  • In addition to this, a complete medical history will aid in arriving at a definitive diagnosis
  • X-ray: This diagnostic test helps provide a clear image of the thoracic outlet space

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Thoracic Outlet Syndrome?

Complications associated with Thoracic Outlet Syndrome include permanent damage to the nerves and blood vessels, which may lead to several medical problems and cause severely impaired functions.

How is Thoracic Outlet Syndrome Treated?

The majority of Thoracic Outlet Syndrome cases respond to conservative treatment, if the condition is diagnosed early. These include:

  • Relaxation techniques, such as controlled breathing, can relieve tension within the shoulders and help maintain proper posture
  • Applying ice to the shoulder/arm/chest can help reduce pain and swelling
  • Non-steroidal anti-inflammatory oral medications, such as indomethacin and naproxen, may be used to treat TOS. These medications can help decrease the pain and swelling
  • Individuals are likely to need physical therapy. Goals of these exercises are to strengthen the muscles within the collarbone, improve flexibility, and decrease stiffness. It may take several months for an individual to complete the physical therapy program

Surgical treatment measures are:

  • Anterior supraclavicular approach: Anterior supraclavicular approach is a surgical procedure to repair the compressed blood vessels
  • Transaxillary approach: Transaxillary approach is a surgical procedure in which, an incision is made on the chest, in order to access the first rib. The compression is relieved by removing part of the first rib

How can Thoracic Outlet Syndrome be Prevented?

Individuals, who begin to exhibit symptoms of Thoracic Outlet Syndrome, should refrain from lifting/pulling/carrying heavy objects. Lifting heavy objects may result in added pressure to the collarbone and other areas around the thoracic outlet. A few other ways to help prevent a TOS include:

  • Individuals, whose occupations require a lot of lifting of heavy loads, such as construction workers, dock workers, should take frequent breaks and avoid prolong periods of such intense work
  • Maintain a healthy body weight to reduce unwarranted stress on the joints

What is the Prognosis of Thoracic Outlet Syndrome? (Outcomes/Resolutions)

  • A majority of the individuals, who develop Thoracic Outlet Syndrome and undergo surgery for the condition, have a full recovery
  • A small percentage of patients may experience a recurrence of the symptoms, even after surgical management of the condition

Additional and Relevant Useful Information for Thoracic Outlet Syndrome:

The following DoveMed website link is a useful resource for additional information:

Was this article helpful

On the Article

Maulik P. Purohit MD MPH picture
Approved by

Maulik P. Purohit MD MPH

Assistant Medical Director, Medical Editorial Board, DoveMed Team


Please log in to post a comment.

Related Articles

Test Your Knowledge

Asked by users

Related Centers


Related Specialties

Loading card

Related Physicians

Related Procedures

Related Resources

Join DoveHubs

and connect with fellow professionals

Related Directories

Who we are

At DoveMed, our utmost priority is your well-being. We are an online medical resource dedicated to providing you with accurate and up-to-date information on a wide range of medical topics. But we're more than just an information hub - we genuinely care about your health journey. That's why we offer a variety of products tailored for both healthcare consumers and professionals, because we believe in empowering everyone involved in the care process.
Our mission is to create a user-friendly healthcare technology portal that helps you make better decisions about your overall health and well-being. We understand that navigating the complexities of healthcare can be overwhelming, so we strive to be a reliable and compassionate companion on your path to wellness.
As an impartial and trusted online resource, we connect healthcare seekers, physicians, and hospitals in a marketplace that promotes a higher quality, easy-to-use healthcare experience. You can trust that our content is unbiased and impartial, as it is trusted by physicians, researchers, and university professors around the globe. Importantly, we are not influenced or owned by any pharmaceutical, medical, or media companies. At DoveMed, we are a group of passionate individuals who deeply care about improving health and wellness for people everywhere. Your well-being is at the heart of everything we do.

© 2023 DoveMed. All rights reserved. It is not the intention of DoveMed to provide specific medical advice. DoveMed urges its users to consult a qualified healthcare professional for diagnosis and answers to their personal medical questions. Always call 911 (or your local emergency number) if you have a medical emergency!