Thoracic Outlet Syndrome

What is Thoracic Outlet Syndrome?


What is Thoracic Outlet Syndrome?

Thoracic outlet syndrome (TOS) is a group of disorders involving compression of the nervous, arterial or venous system around the neck and shoulder joint, commonly giving neurological symptoms such as numbness, tingling or burning sensation, pins and needles and weakness into the arms.

Thoracic outlet syndrome can be a very challenging diagnosis as symptoms and causes of pain around the neck and shoulder are often overlapping. Due to the high number of differential diagnosis causing peripheral nerve compression a thorough examination must be carried out to rule out progressively damaging conditions that might need onward referral.

Thoracic outlet syndrome is one of the most common differential diagnoses considered by musculoskeletal practitioners when dealing with complaints involving radiating symptoms down the arm or local pain around the side of the neck, the scapula (shoulder blade) and the shoulder joint. Nervous involvement also called nervous thoracic outlet syndrome (NTOS) occurs 95% of the time with arterial and venous TOS occurring for the remaining 5% of the time. Causes of TOS can vary from wear and tear of the cervical spine (neck), to muscular hypertrophy or abnormal anatomical position of the clavicle, 1st rib or brachial plexus causing compression of the nerve structures.

With a correct and early diagnosis of TOS, musculoskeletal healthcare practitioners such as osteopaths, chiropractors and physiotherapists can help relieve the pain and symptoms experienced and try to resolve the reasons causing the compression of the structures. If the condition is ongoing due to anatomical variations or due to trauma or other underlying health conditions, the primary healthcare practitioner may refer you for further investigation such as X-ray, MRI, CT scan, nerve conduction test and arteriography and venography and a different treatment approach may be introduced.

What are the symptoms of Thoracic Outlet Syndrome?

Symptoms of TOS depend on the type (neurological, arterial or venous) but usually include numbness, tingling or burning sensation, pins and needles and weakness into the arms, hands and fingers. Arterial and venous types of TOS can cause symptoms such as cold and stiff hands.

What are the common causes of Thoracic Outlet Syndrome?

Causes of thoracic outlet syndrome can vary depending on the area that is involved and the structure that is affected. As mentioned above TOS can be due to neurogenic involvement called NTOS, arterial involvement called ATOS and venous involvement called VTOS. According to research NTOS comprises 95% of all cases with VTOS and ATOS comprising 4% and 1% respectively.

Thoracic outlet refers to the anatomical area found at the bottom of our neck and its borders are the lateral neck, the clavicle and the 1st rib. Through this triangular space the subclavian artery, vein and the brachial plexus pass and travel down the arm and forearm supplying the muscles and tissues with blood, nutrients and nerve signals. Structures that could compress one or more of the three structures mentioned earlier vary between bones, muscles and vertebral discs.

  • Anatomic variations between individuals can cause compression of the structures. A narrow space between the clavicle and the 1st rib is seen in some people and is a common site of compression. 1-2% of the whole population may have a unique anatomic feature of a cervical rib which is found at the top of the 1st rib, causing an even narrower space for the nerve bundles to pass through.
  • Traumatic injuries such as falls, road traffic collisions or other whiplash type of injuries from sports can cause damage to certain structures around the neck and shoulder. Four common sites include the cervical spine, the shoulder, the elbow and the wrist. A cervical spine disc bulge or herniation or an unstable neck fracture can cause compression of the nerve roots leaving the neck to travel down the arm. Shoulder dislocation or a clavicle fracture can impinge the nerves, arteries or veins that leave the shoulder to travel down the arm. This can lead to neurological symptoms or the formation of hemorrhage or hematoma restricting blood flow to the arm. Elbow dislocation or hyperextension type of injury can cause trapping of one of the nerves of the brachial plexus. Finally severe wrist strain or wrist fracture can impinge two of the nerves entering the palm and supplying the digits.
  • Repetitive motions can cause certain muscles to work really hard leading to muscle hypertrophy. If nerves, arteries or veins pass near or through these muscles, compression of the structures is very likely to occur leading to symptoms of TOS. The population that is often affected are people that do overhead movements like painters and electricians. Also, athletes involved in sports such as water polo, swimming, tennis, baseball, cricket and climbing can often be affected.
  • Tumours, malignant more than benign can cause compression of the brachial plexus. However this is not a very common cause. Pancoast tumour is the most common malignant tumour that develops in the top portion of the lungs and can compress the nerves passing through. However, this is only found in people over the age of 60 that have been chronic heavy smokers with other underlying conditions.

How is Thoracic Outlet Syndrome diagnosed?

As with any condition, early and accurate diagnosis of TOS can help with the management in the acute phase by reducing pain and symptoms experienced and in the chronic phase by preventing recurrence and improving quality of life. Individuals usually seek help and treatment once they have started to have symptoms often accompanied by pain. At the beginning signs and symptoms are usually mild therefore people will seek help from their GP or some musculoskeletal specialist such as physiotherapist, osteopath or chiropractor. Thoracic outlet syndrome secondary to traumatic injury means that the individual will most likely go straight to A&E.

In the first and most common case the musculoskeletal specialist will take a detailed case history of the presenting signs and symptoms and will ask specific questions to rule out any conditions that may require onward referral and to narrow down the possible causes of the presenting problem. A circulatory and neurological examination will be carried out which involve the practitioner checking your peripheral pulses and temperature of your hands followed by some muscle testing, reflexes and sensory exam. Then, a careful examination of the muscles and joints that the nervous, arterial and venous system passes through is examined to find any possible sites of restriction or compression. In some occasions the quality and range of movement of the neck and shoulder may also be tested. Finally, provocative tests of the peripheral nerves will be carried out on your neck, shoulder, elbow and wrist, aiming to recreate some of the symptoms in order to form an accurate diagnosis.

Complementary investigation modalities may be used in cases when the presentation of the signs and symptoms is not very clear. A list of the specialized tests that can be carried out is shown below:

  • MRI: Can be used to check for tumours and cysts on the upper lungs and to check for vertebral disc and other soft tissue injuries that could be contributing to the problem.
  • Doppler ultrasound and angiography are used to check the vascular system and to find out of any possible blood flow restrictions due to compression or vessel size reduction.
  • Electroneuromyography can detect neurological abnormalities but is only valid in severe cases.

What are the treatment options for Thoracic Outlet Syndrome?

Depending on the type of TOS (arterial, venous or neuro) a slightly different treatment approach might be used. General treatment options for TOS can be split into conservative treatment and surgical management. With mild arterial and venous TOS a conservative approach may be used in order to avoid the surgical intervention. However, if signs and symptoms are progressing and the quality of life of the individual is getting worse a surgical intervention may be required.

Conservative treatment will be used first in the majority of the cases, especially for neuro TOS as it has shown to be very effective at managing the symptoms and the progression of the condition. One aspect of the approach will look at how to prevent further damage or aggravation of the symptoms whilst the other one will focus on the rehabilitation of the tissues.

  • Prevention: Lifestyle changes involve postural improvement, retraining of sleeping habits and changes in exercise and working routines. Maintaining an upright posture with the neck, upper back and shoulders drawn back can help decompress some of the tissues. Avoiding sleeping on the front with the arms overhead or onto the side with the weight of the body over one shoulder can help relieve some of the symptoms and improve tissue health. Finally, an ergonomic assessment of the working environment can help avoid repetitive movements or positions that could put the tissues under stress. Same thing can be applied during exercise. A personal trainer, physiotherapist or osteopath can give you advice on how to keep your fitness up but avoiding certain exercises or movements that could lead to TOS.
  • Physical Therapy: The hands on approach will look into decompression of the areas that the arterial, venous or neural tissues are most likely trapped, which can be found around the neck, under the clavicle and the shoulder and onto the elbow, wrist and hand. Manipulation, mobilization, stretching and massage techniques will be used by the manual therapists. Postural and exercise/stretching advice will be provided to help achieve full recovery. Evidence shows that pain levels and nerve irritation from TOS can decrease even after one physical therapy consultation and long term prevention can also be achieved.

In some cases surgical intervention may be required. The most appropriate type of surgery will be discussed with you by your consultant.

Can Thoracic Outlet Syndrome be prevented?

Not all causes of Thoracic Outlet Syndrome can be prevented. However there are a few things that can be done to reduce the risk:

  • Maintaining a good posture when sitting down and taking regular breaks every 30-60 mins when working.
  • Avoiding activities that require the arms to be overhead and heavy lifting on the shoulders.
  • Breathing exercises and self massage on the upper back, chest and shoulders using a foam roller or a tennis ball.
  • Improving technique of specific exercises or slightly changing our fitness routine can once again prevent the build up of tissue tension which could lead to TOS.
  • Improving working set up is essential as we tend to spend at least one third of our day there, most days of the week. Adjusting the height of the screen to eye level, getting a seperate keyboard at elbow level and a proper chair can have a very positive effect on the prevention of restriction formation on certain tissues, leading to TOS.
  • Improving sleeping position can not only prevent TOS but can help with the overall health of an individual as getting adequate and high quality rest is essential.

What are the best exercises for Thoracic Outlet Syndrome* ?

Certain exercises and stretches can help prevent neurological TOS to a great extent. If done on a weekly routine along with some advice and improvements of lifestyle, the change of symptoms can be massive and the prevention of further episodes or the need of surgical intervention may be reduced. Some stretches are listed below. It is always recommended to get the go- ahead from your GP or physical therapist before carrying out any of these exercises.

  • Pectoralis major & minor stretch. Stand next to a door frame and place your forearm flat on the wall with your elbow and shoulder bent at 90 degrees. Keeping your back and neck straight do a small lunge with the leg closer to the wall whilst pushing your chest out in front of you. Once you feel the stretch on the front of yourchest maintain the position for 30-60 seconds. Then repeat the same thing by bringing your shoulder to 110 degrees whilst maintaining contact with the wall using your forearm.
  • Shoulder rolls. Keeping both arms relaxed onto your side, start slowly rolling your shoulders upwards then forwards then downwards and back to the starting position. Repeat for 10 circles in one direction and then repeat the same thing by rolling your shoulders backwards.
  • Trapezius stretch. Keeping your back straight, bend your neck to one side and reach with the other hand on the head and apply a gentle pull until a stretch is felt. Maintain the position for 30 seconds and repeat on the other side.
  • Levator scapula stretch. Keeping your back straight turn your head 45 degrees and drop your chin to your chest. Reach with the opposite hand on the head and apply a gentle pull until a stretch is felt. Maintain the position for 30 seconds and repeat on the other side.
  • Neck isometrics. Place a hand on the forehead and gentle press into it holding the position for 5 seconds. Repeat the same thing by placing the hand on either side and back of the head pressing and holding for 5 seconds. Repeat 3-5 times in each direction.
  • Theraband face pulls. Place a theraband around something stable at chest height. Take a couple of steps back whilst holding each end with each hand. Keeping your back straight and shoulders abducted to 90 degrees, pull the band towards your face activating the muscles between the scapula. Slowly return to the starting position and repeat for 3 sets of 12-15 repetitions. To increase the level of difficulty move further back to increase the tension in the band.
  • Diaphragmatic breathing. Lie on your back with your knees bent and feet flat on the floor. Place one hand onto the abdomen and the other one onto the upper chest. Take a deep breath through the nose aiming to push the air down to your abdomen. Slowly exhale through the nose and repeat for 3 sets of 10 breaths. During each inhalation, always aim for the hand on the abdomen to rise before the hand on the chest rises.

Do I need to go to the GP or visit my local hospital?

Unless experiencing sudden and acute pain around the neck with radiation down one or both arms or you have been in a traumatic accident such as road traffic collision, fall or trauma from sports, injuring your neck, upper back, shoulders and arms there is no need to go to the local hospital. If none of the above apply however, you have been experiencing debilitating pain that is getting worse with time and is affecting your quality of life and is stopping you from working, you should visit your GP who will be able to refer you onwards to the right specialist.


Jones, M., Prabhakar, A., Viswanath, O., Urits, I., Green, J., Kendrick, J., Brunk, A., Eng, M., Orhurhu, V., Cornett, E. and Kaye, A., 2019. Thoracic Outlet Syndrome: A Comprehensive Review of Pathophysiology, Diagnosis, and Treatment. Pain and Therapy, 8(1), pp.5-18.

Kaplan, J., Kanwal, A., Thoracic Outlet Syndrome. (updated 2020 Nov 17). In: StatPearls (internet). Treasure Island (FL): StatPearls Publishing 2021 Jan.

Laulan, J., Fouquet, B., Rodaix, C., Jauffret, P., Roquelaure, Y. and Descatha, A., 2010. Thoracic Outlet Syndrome: Definition, Aetiological Factors, Diagnosis, Management and Occupational Impact. Journal of Occupational Rehabilitation, 21(3), pp.366-373.

Levine, N. and Rigby, B., 2018. Thoracic Outlet Syndrome: Biomechanical and Exercise Considerations. Healthcare, 6(2), p.68.

Povlsen, S. and Povlsen, B., 2018. Diagnosing Thoracic Outlet Syndrome: Current Approaches and Future Directions. Diagnostics, 8(1), p.21.

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