by Kyle Sandoval, PT, DPT

What is Thoracic Outlet Syndrome?

Thoracic outlet syndrome (TOS) refers to a condition involving the compression of nerves and blood vessels as they pass through a part of the body called the thoracic outlet. This area is bordered by the collar bone, side of the neck, shoulder blade and top of the first rib.1 TOS can lead to symptoms located in a variety of areas ranging from your neck to finger tips. These symptoms include aching pain mostly along the side of the neck to the shoulder. Other symptoms can include numbness, tingling sensations, headaches, muscle weakness, changes in skin color and changes in skin temperature.

The most common symptom of TOS is numbness and tingling in the hand and the inside of the forearm which occurs in 98% of those affected.2 Symptoms are often provoked or worsened by reaching overhead, reaching backwards, or by certain neck positions. TOS can be subcategorized by whether nerves or blood vessels are being compressed. 90% of cases are known as neurogenic TOS, characterized by compression of nerves within the brachial plexus. The brachial plexus is a bundle of nerves that passes through the thoracic outlet. In the other 10% of cases, blood vessels such as the subclavian artery and/or vein are compressed in the thoracic outlet, this is called either arterial or venous TOS.3 TOS can also be defined by the anatomical location of the compression.4 Examples include:

Anterior Scalene Syndrome: The compression of nerves or blood vessels occurs between 2 of the scalene muscles, which are located on the sides of the neck.

Cervical Rib Syndrome: A cervical rib is a small ‘extra rib’ that arises in the lower part of the neck. Cervical ribs are present in 1 in 500 people. People with these extra ribs are at greater risk for developing TOS due to decreased space for nerves and blood vessels to pass through the thoracic outlet.

Costoclavicular Sydrome: Compression in-between the 1st rib and the collar bone.

Hyperabduction Sydrome: Compression occurs under the pectoralis minor muscle where your chest meets your shoulder.

Who gets Thoracic Outlet Syndrome?

Most people who develop TOS are in their 20s and 30s. Women develop this condition slightly more often than men; those who are overweight are also at greater risk. Prolonged poor sitting and poor posture combined with repetitive hand activities such as typing on a computer are prime contributors to the gradual development of TOS. Trauma to the neck such as whiplash during an auto accident or the shoulder can lead to TOS developing more suddenly. About half of diagnosed TOS cases are caused by trauma.2

How is Thoracic Outlet Syndrome diagnosed?

TOS is clinically diagnosed through a physical examination that may include assessing strength, sensation, and placing your neck, arms, and hands in positions that may momentarily provoke symptoms.4 Other methods involved in diagnosing TOS focus on ruling out other conditions such as cervical disc pathologies with the use of medical imaging. Nerve conduction tests may be useful in assessing patients with neurogenic TOS. Vascular tests such as a brachial artery angiography, venography, doppler ultrasonography can help diagnosis arterial or venous TOS.1,2 TOS can be misdiagnosed as carpal tunnel syndrome, cervical disc pathologies, or other conditions that may cause pain and tingling in the upper extremity.5 The frequency of the misdiagnosis of TOS has been difficult to pinpoint but researchers believe that anywhere from 3 to 80 out of every 1,000 have this condition.6

How can Thoracic Outlet Syndrome be treated?

Conservative treatments such as physical therapy are most often successful in treating TOS. Physical therapy treatment for TOS will vary from person to person but may include correction of posture with an emphasis on strengthening muscles necessary to maintain posture throughout the day.4 Physical therapists often have expertise in assessing postural and functional abnormalities that may contribute to TOS.

Physical therapy typically includes the strengthening of muscles of the hand, arm, and shoulder girdle. Treatment may also include stretching of tight muscles in the neck and chest, and other techniques to relieve pain and inflammation, http://www.papsociety.org/prednisone/. If conservative treatments are not effective surgery can be performed to treat TOS. There are many different types of surgery for TOS, with most involving widening the Thoracic outlet in some way.4 In the case of costoclavicular syndrome or first rib syndrome, the rib compressing on the nerves, arteries, and/or veins may be removed.3 Overall about 83% of patient’s demonstrate significant improvements after surgery.7
Kyle Sandoval, PT, DPT, has been practicing physical therapy since 2013. Kyle has developed an interest in TOS and other conditions involving nerve compression and postural abnormalities. When away from work, he enjoys hiking, camping, running and various martial arts.


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  1. Chang AK, Bohan S, Kraus RS. Thoracic Outlet Syndrome. eMedicine. Published Feburary 4, 2008. Accessed April 13, 2014.
  1. Yavuzer P, Atinkaya C, Tokat O. Clinical predictors of surgical outcome in patients with thoracic outlet syndrome operated on via transaxillary approach. Eur J Cardiothorac Surg. 2004;25:173-178.

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