Thoracic Outlet Syndrome

Thoracic Outlet Syndrome (TOS) is a condition that occur when blood vessels, arteries or veins in the space between your collarbone and your first rib (thoracic outlet) are compressed. There are three main types of this syndrome – neurogenic, venous and arterial. The neurogenic type is the most common type and is caused by compression of components of brachial plexus nerves. Arterial type of Thoracic Outlet Syndrome is rare and is caused due to compression of subclavian artery. Venous type is extremely rare type of TOS and is caused due to compression of subclavian vein.

Symptoms of Thoracic Outlet Syndrome

Symptoms may vary depending on which nerves or blood vessels are compressed. However, common symptoms include neck and shoulder pain, arm pain, numbness and tingling of the fingers and impaired circulation to the extremities. Compressed blood vessels cause swelling, redness and weakness of the arms.

These symptoms may worsen when the thoracic outlet is narrowed in certain body positions like when the arm is raised overhead.

TOS can also lead to eye problems including vision loss because of vertebral artery compression. Some other complications that can be caused by Thoracic Outlet Syndrome are Ischemic ulcers of the fingers, Gangrene, Pulmonary embolism and neurogenic complications such as permanent nerve damage.



Congenital problem like extra first rib (cervical rib)
Certain trauma like a car accident
Drooping Shoulders
Old fracture of the clavicle (collarbone)
Bony and soft tissue abnormalities
Unknown causes

It is more common in women and occurs commonly between 20 and 50 years of age.
Other risk factors include

Sleep disorders
Tumors that press on nerves
Repetitive arm and shoulder movements
Repetitive injuries from carrying heavy shoulder loads
Injury to the neck or back
Poor posture
Weight lifting



Treatment for Thoracic Outlet Syndrome

Treatment depends on what caused your Thoracic Outlet Syndrome and generally does not include surgery

Non-steroidal anti-inflammatory drugs are given to reduce the swelling and pain so that patient can be put on physical exercises

Physical Therapy is mainly recommended to strengthen the muscles surrounding the shoulder. Some postural exercises are also taught to improve the overall posture which helps reduce pressure on the nerves and blood vessels.

Doctor will advise you to stop certain strenuous activities and recommend certain changes in the lifestyle.


Surgery is advised if all non-surgical treatments fail to relieve the symptom. It is estimated that only 10 to 20% of patients with TOS need surgical treatment. It is often microsurgery which is performed to remove portion of abnormal first rib or to release muscles that joint the neck and chest, or to reroute blood vessels around the thoracic outlet.

Physical therapy is often used before and after the surgery to improve recovery.


Prevention of Thoracic Outlet Syndrome

Practicing proper posture while sitting and standing
Taking breaks at work
Maintaining a healthy weight
Not sleeping with arms above your chest
Performing strengthening exercises
Avoiding lifting heavy objects

For questions related to Thoracic Outlet Syndrome, you can write to

Q&As Thoracic outlet syndrome


  1. What are the types of thoracic outlet syndrome?
  • Thoracic outlet syndrome is a group of disorders resulting from compression of the bundle of nerves and blood vessels, both arteries and veins, present in the space between collar bone (clavicle) and the first rib. 
  • Depending on which structure is getting compressed, there are 3 types of thoracic outlet syndrome:
  • Neurogenic (neurological) TOS – This is the most common type of TOS. The bundle of nerves (called brachial plexus) that passes through the space between the collar bone and the first rib is compressed in this. It causes neck and shoulder pain, numbness or tingling in the arm or fingers, weakening grip.
  • Venous TOS – This is caused by a compression of the veins in the region. The affected arm has pain and swelling, bluish discoloration or paleness in one or more fingers, or throbbing mass in the collar bone region. There is usually a blood clot in the compressed vein.
  • Arterial TOS – This is the rarest type of TOS. When there is compression of the arteries in the region, it causes cold arms, fingers, and hand, pain in the affected arm or hand, paleness or discoloration of the fingers or the entire hand, and weak or no pulse in the arm. This is usually due to a congenital (present at birth) abnormality where the individual has an extra first rib or cervical rib.


  1. How do you test for thoracic outlet syndrome?
  • The diagnosis of thoracic outlet syndrome is difficult, and some individuals may live with it undiagnosed for a long time. Doctors do a thorough physical examination with a detailed medical history of the symptoms to arrive at the diagnosis. 
  • It is important to rule out other conditions which present with similar symptoms.
  • Apart from a physical examination, an ultrasound, computed tomography (CT) scan, Magnetic Resonance Imaging (MRI), arteriography or venography, and nerve conduction studies are done to diagnose the various types of thoracic outlet syndrome. 


  1. How is thoracic outlet syndrome treated?
  • Most cases of thoracic outlet syndrome respond to non-surgical treatment, which consists of:
  • Physical therapy – For neurogenic TOS, this is the best, and the first treatment advised. Exercises to slowly strengthen and stretch the shoulder muscles to open the thoracic outlet are taught to the patient. This is effective in most cases.
  • Medication – Individuals with TOS shall be prescribed with painkillers for pain relief, muscle relaxants to aid muscle relaxation, and anti-inflammatory medication to decrease inflammation. Thrombolytics like warfarin and heparin are prescribed in case of blood clots to help dissolve them. Doctors also prescribe blood thinners to prevent further blood clots to form.
  • Surgery – It is rarely needed but if physical therapy and medication do not provide relief, surgical options are explored. It is called decompression surgery. 


  1. What causes thoracic outlet syndrome?
  • Thoracic outlet syndrome is most commonly caused by repetitive arm or shoulder movements, especially overhead movements. Poor posture like drooping shoulders also causes TOS.
  • A congenital anomaly like the extra first rib or cervical rib puts pressure on the artery in the thoracic outlet and causes arterial TOS. 
  • Pregnancy can also be a cause for it. Women and individuals between the ages of 20 to 50 years are at higher risk of developing TOS.


  1. What happens if thoracic outlet syndrome is left untreated?
  • If thoracic outlet syndrome is left untreated, it can cause increased pain and discomfort. It can also cause decreased function. 
  • In the case of arterial and venous TOS, it can cause massive, life-threatening blood clots.


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