By Laurie Melrose-Doering, Osteopath & Applied Kinesiologist
Thoracic outlet syndrome (TOS) describes compression of the nerves and blood vessels as they pass from the neck and thoracic outlet into the shoulder and arm.
TOS has a very broad list of symptoms, ranging from pins and needles or numbness in the fingers and hand, to neck pain, chest pain, shoulder pain, and arm pain. The long list of possible symptoms is down to the many sites – such as the first rib, and collarbone shoulder muscles – that are usually involved.
The thoracic outlet is broadly the space between the neck muscles and each shoulder. Blood vessels and nerves to and from the arm pass through this space – and it is here that they are easily compressed.
In most cases, there is more than one active entrapment site. Osteopaths therefore need to address several areas – only focussing on one site is unlikely to resolve the symptoms, as it will not treat all root causes.
The main sites of compression are called entrapment sites. They are:
Thoracic outlet syndrome is 3–4 times more common in women than men. The main reason is that women have breast tissue and therefore a greater tendency to drooping shoulders. Anatomically, women also have a narrower thoracic outlet and a lower sternum, which changes the angle of the scalene muscles.
You are also at increased risk of developing TOS if you have an asthmatic breathing pattern. Asthmatics use the so-called accessory muscles of breathing to expand their chest volume. This then allows more air to be sucked into the lungs on inhalation.
As the accessory muscles are excessively used, they tighten up. And because some of these muscles (pectoralis minor, scalenes) act as entrapment sites, they increase the risk of TOS.
Similarly, a history of whiplash increases the risk of TOS. Left untreated, whiplash eventually causes the neck and shoulder muscles to tighten up. Tightening of muscles (hypercontracture) is a common follow-on from weak muscles – which are often found immediately after a whiplash. And this tightening, just as in asthmatic breathers, can lead to entrapment sites.
Another risk factor is pregnancy. This is because the body secretes the hormone relaxin in order to prepare the body for labour.
Relaxin relaxes ligaments, which loosens the joints. As a result, it is easier to develop poor posture, which will lead to narrowing of the thoracic outlet.
A typical posture that may be found in patients presenting with TOS is a forward head carriage. Forward head carriage is seen in upper crossed syndrome, which I have written about in this osteopathy post.
Owing to the fact TOS is such a broad condition, with many entrapment sites contributing to the pain, symptoms are very broad.
Possible symptoms are:
Because TOS symptoms are so varied, the list of conditions on a clinician’s differential diagnosis can be quite extensive – it can encompass a slipped disc in the neck, tennis or golfer’s elbow, shoulder impingement, carpal tunnel syndrome, or rotator cuff injuries.
In addition to this, if TOS symptoms are present on both sides of the body, it is important to exclude systemic causes. These range from type-2 diabetes and hypothyroidism to rheumatoid arthritis and amyloidosis. They all have in common an increased amount of fluid in the tissues that may impinge on nerves.
As a result, some practitioners find TOS difficult to diagnose. Osteopaths and chiropractors, however, treat TOS all the time. We therefore find it easier to diagnose than most clinicians.
As an osteopath, I start with observation and palpation. That is, I examine the posture for asymmetries and feel for tension in the muscles that can act as entrapment sites.
Then I challenge the peripheral nerves that are likely to be impinged by testing which arm positions bring on tingling in the fingers.
I then test 15–20 muscles around the shoulder to pinpoint any weaknesses. Finally, I examine the neck, as this is where the nerve supply to the muscles arises.
This depends on the entrapment sites. But in general, stretching of the pectoralis minor and scalene muscles, as well as opening up of the thoracic outlet by doing backstroke-type exercises, are effective.
Work on the pectoralis minor muscle, trapezius and scalene muscles is almost always implicated.
Acupuncturists will work on the local shoulder muscles and with the meridians/channels that travel along the shoulder and arm. Acupuncture can be very useful in the treatment of TOS.
Surgery is only indicated in the rare cause of a cervical rib. And even then, it may not be required.
Osteopathic treatment for thoracic outlet syndrome is very effective. The number of appointments depends on the severity of the symptoms and the number of entrapment points, so it is difficult to give an estimate that applies to every patient. I have found, however, that the large majority of patients improves in less than 5 appointments.
Overall, osteopaths have an amazing arsenal to treat TOS: we work with the shoulder joints, treat the diaphragm, the nerve supply to the shoulder muscles via the spine, the peripheral nerves, the local muscles, and more.
If you think you may have thoracic outlet syndrome, please get in touch.
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Aston Clinic London is a third-generation complementary health clinic located in New Malden, serving Kingston, Norbiton, Wimbledon, Raynes Park, Surbiton, Chessington, Worcester Park, Sutton, Richmond, and other areas of southwest London and Surrey.
By Laurie Melrose-Doering, Osteopath & Applied Kinesiologist
