What Is Thoracic Outlet Syndrome?


January 26, 2021     arms | neck | pain | Anatomy | Torso | Upper Limb | Yoga Injuries

Understanding thoracic outlet syndrome

You may or may not have heard of the thoracic outlet, much less the syndrome. However, it’s an important area to be aware of. In this article we’ll take a look at where it is, what structures are involved, and where it is most likely to show up, both in everyday life as well as in your yoga practice.

As you’ll see, the thoracic outlet includes both nerves and a blood supply that feeds the arm all the way down to the fingers. Dysfunction at the thoracic outlet can lead to a variety of pain or other sensations all the way down to the fingers, making it a little more complicated to diagnose. For example, is the pain coming from where you feel it in the hand or arm, or is it coming from an area near your neck (the thoracic outlet)?

What and where is the thoracic outlet?

The thoracic outlet is a space on the side of your neck where the brachial plexus (the bundle of nerves that feed the arm), subclavian artery, and subclavian vein pass through the anterior and middle scalene muscles, and then descend between the clavicle (collar bone) and the first rib. From there, those structures then pass under the pectoralis minor muscle and the coracoid process, which is the bony landmark on the scapula that the pectoralis minor muscle attaches to. (Even though you think of your scapula as being on your back, your scapula actually has a bony landmark that is in the front of your body called the coracoid process.)

What is thoracic outlet syndrome?

Thoracic outlet syndrome is a disorder caused by the compression of nerves, arteries, and/or veins that pass through the spaces of the thoracic outlet. Symptoms usually include pain which can be felt in the head, neck, shoulder, arm, and/or chest. The location of the pain is generally correlated with the specific nerve roots between C5 and T1 that are being compressed. Other symptoms can include numbness and tingling, particularly in one or more of the fingers, as well as muscle weakness. These symptoms can overlap with symptoms of other conditions or types of dysfunction, such as carpal tunnel syndrome.

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Thoracic outlet syndrome has three sub-types:

  • Neurogenic
  • Venous
  • Arterial

The subtypes are based on the causes and specific compression experienced. The neurogenic type of thoracic outlet syndrome is the most common, and specifically means there is a compression of the nerve roots of the brachial plexus somewhere between C5 – T1. The venous type of thoracic outlet syndrome occurs when the subclavian vein is compressed at some point along its path through the thoracic outlet. Similarly, the arterial type of thoracic outlet syndrome occurs when the subclavian artery is compressed at some point along its path through the thoracic outlet. Most cases of thoracic outlet syndrome are of the neurogenic type, while a much smaller percentage are either the venous or arterial type. The compression is more commonly located on one side of the body, but can occur on both sides.

What causes the compression?

Compression of the nerves, veins, and/or arteries can be caused by bones, muscles (such as scalenes, pectoralis minor, or coracobrachialis), or both. Rarely, compression can also be caused by other tissues such as either benign or malignant tumors. The source cause can be genetic, such as being one of a small percentage of people who are born with a cervical rib, or with a particular location/orientation of the first rib, which makes compression of the brachial plexus more likely. Compression can also be a result of trauma such as a car accident or a fall. Commonly, compression of the brachial plexus structures can also result from repetitive actions in work, sports, or other activities.

How is thoracic outlet syndrome diagnosed?

Due to the complex nature of the causes and the symptoms of thoracic outlet syndrome, it’s usually diagnosed by a combination of multiple tools including:

  • A thorough personal intake including work and leisure activities, injuries and accidents, and specific experience of pain, numbness, tingling, etc.
  • A physical exam
  • Radiographic imaging
  • Other tools

A difficulty in diagnosis of thoracic outlet syndrome is in distinguishing it from other disorders with overlapping and/or similar symptoms, such as frozen shoulder, rotator cuff tendonitis, rotator cuff dysfunction or tears, and carpal tunnel syndrome.

Treatments for thoracic outlet syndrome

The method of treatments for thoracic outlet syndrome vary based on the specific situation of the patient, particularly with respect to which structures are being compressed, where the compression is occurring, and why the compression is occurring (injury/accident, genetic, repetitive habits).

Some treatments might include one or more of the following:

  • Pain management through medications, NSAIDs, or other anti-inflammatory medications
  • Modification of contributing activities such as repetitive actions at work or in sports
  • Modification of postural habits
  • Physical therapy and rehabilitation
  • Acupuncture
  • Surgery
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Thoracic outlet syndrome and yoga

It is possible for your yoga practice to contribute to thoracic outlet syndrome, but what is more likely if you have been diagnosed with thoracic outlet syndrome, is that there are other underlying postural problems contributing to that condition. Those postural issues could be as simple as spending large amounts of time in front of a computer.

The two most common causes that I’ve seen are either one or both of the following:

The first is overusing the secondary respiratory muscles. In this situation, the diaphragm is not doing its work as the primary muscle of respiration for some reason. It’s possible that it is simply tight, but for some reason it is forcing us to use those scalenes as secondary respiratory muscles. By overusing them in this way, we can add additional tension to the muscles and potentially compress the brachial plexus.

The second cause for thoracic outlet syndrome that I have commonly seen is straining the neck muscles. Postures that require a lot of effort for us sometimes cause us to tighten our neck muscles in ways we do not even realize. Chaturanga and arm balances of any type are the most likely places where you could be overusing the neck muscles and unknowingly straining them. I’m not talking about the muscle simply contracting. I’m talking about repetitive movement that leads to a dysfunctional level of tension. This stress and strain lead to additional tension in the neck muscles including the scalenes.

What can we do about it?

So, can yoga help manage thoracic outlet syndrome? Maybe. It depends on the individual situation. What yoga can do is help maintain length in the neck muscles which can help maintain space in the thoracic outlet. We might especially focus on lengthening the scalenes and pectoralis minor. Even if we’re not experiencing something as extreme as thoracic outlet syndrome, we could all probably use a little more attention and length in these muscles, which tend to get short and tight from holding the posture we often use at the computer and when driving a car, as well as in many sports.

One of the most simple places to find the length in these muscles is in postures such as upward facing dog where we have an opportunity to lengthen the front of the neck. Also, pay attention to what you’re doing with your neck in other postures that would shorten and potentially tighten the scalenes in particular, to avoid making the thoracic outlet space smaller.

Conclusion

Thoracic outlet syndrome is just one reason why you might experience pain, numbness, or tingling in the neck, shoulder, arm, and hand. If you think you’re experiencing compression of the structures that pass through the thoracic outlet, see an appropriate medical professional. For everyone else, consider including some postures in your yoga practice that help maintain openness of the muscles of the neck and shoulders to support the general health of this chain of joints.

References

Balderman, J., A.A. Abuirqeba, L. Eichaker, C. Pate, J.A. Earley, M.M. Bottros, S.N. Jayarajan, and R.W. Thompson. 2019. Physical therapy management, surgical treatment, and patient reported outcomes measures in a prospective observational cohort of patients with neurogenic thoracic outlet syndrome. Journal of Vascular Surgery. 70(3):832-841.

Hwang, J.H., S. Ku, and J-H. Jeong. 2020. Traditional medicine treatment for thoracic outlet syndrome. A protocol for systematic review of randomized control trials. Medicine. 99:27-30.

Jones, M.R., A. Prabhakar, O. Viswanath, I. Urits, J.B. Green, J.B. Kendrick, A.J. Brunk, M.R. Eng, V. Orhurhu, E.M. Cornett, and A.D. Kaye. 2019. Thoracic outlet syndrome: A comprehensive review of pathophysiology, diagnosis, and treatment. Pain Therapy. 8:5-18.

Ortac, E.A., T. Sarpel, I.C. Benliday. 2020. Effects of kinesio taping on pain, paresthesia, functional status, and overall health status in patients with symptomatic thoracic outlet syndrome: A single-blind, randomized, placebo-controlled study. Acta Orthopaedica et Traumatologica Turica. 54(4):394-401.

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