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  • Writer's pictureRetrain Health

Thoracic outlet syndrome (TOS)

*NB: Blue lines indicating anterior scalenes, clavicle and pecs

Thoracic outlet syndrome (TOS), is an interesting condition that can often go un-diagnosed.

TOS is a compression of the neurovascular structures (nerves, arteries or veins), as they exit through the neck and shoulder region, through the anatomical landmark also known as the thoracic outlet.

In almost all cases of TOS (95-98%), the cause of TOS is from compression of the nerves in the brachial plexus (main plexus/ bundle of nerves that originate from the neck and supply the arm), and the other 2-5% is due to compression of vascular structures, such as the subclavian artery and vein.

The compression can be caused by a few structures;

  • Firstly, it can be as simple as tight musculature, such as the scalenes (muscles at the front of your neck), or the pectroalis major and/or minor (chest muscles), compressing the neurovascular structures.

  • Secondly, the compression can occur from anatomical bony abnormalities. These can be congenital in nature (aka your normal variant, aka a result of slight differences in your development but not usually pathological, aka a quirk!) or as a result of trauma or injury. The photo below demonstrates the common areas where these compressions occur.


As you can imagine, compression of neurovascular structures doesn’t sound that pleasant, and it doesn’t feel it either.

The symptoms of TOS vary depending on whether the compression is in the neck or shoulder region, and if it is compressing nerves or vascular structures (or all of the above).

The symptoms of TOS can occur anywhere along the chest, neck, shoulder, arm, hands and fingers. The symptoms can be isolated to one area of the body, or can travel from your neck all the way down to your fingers.

The typical symptoms of TOS include:

  • Constant pain, that can be worse at night

  • Weakness

  • Numbness

  • Swelling

  • Pins and needles

  • Cold sensitivity

  • Discolouration

Sometimes, TOS may be confused with a heart attack, due to the similarity in some of the symptoms. Therefore, it is always important to speak to your general practitioner or allied health practitioner if you are concerned, so they can conduct a thorough examination to determine the cause of your symptoms.


Your osteopath will be able to make a diagnosis of TOS based on your presentation, case history and examination. The examination will include special tests which help us to identify where the compression is occurring, and it also helps us to rule out any other pathology in the area. Imaging is not necessary for the diagnosis, but in severe cases it may be used to provide clarity on what is causing the compression, degree of pathology and rule in/out the presence of other serious pathologies.

Those symptoms sound familiar, but how did I get TOS?

The typical age group for TOS is 20-50 years old, but it can be seen in younger and older populations (rarely in children).

As discussed earlier, people who are more susceptible to TOS include:

  • Those who have sustained direct trauma to the shoulder or neck region e.g. motor vehicle accident fractruring the clavical

  • Anatomical abnormalities acquired from birth e.g. an extra rib

  • Functional causes resulting in hypertrophy (increased muscle tone) of the scalenes (muscle at the front of your neck) or the pectoralis major and/or minor (chest muscles).

The functional causes are what we often see here at Retrain Health, with the most common example being as a result of repetitive, overhead (or elevated upper limb) motions - think sports such as baseball, tennis, or swimming. There is also a risk of developing TOS in professions such as, painting, hairdressing and electrical work, as well as desk jobs (especially those with poor posture, poor ergonomic set up and repetitive tasks).


The prognosis of TOS varies depending on the type (vascular or nerve compression) and the cause of the compression. If the cause of your TOS is due to functional causes, then the prognosis is favourable, and you should see a response to treatment and management, within a couple of weeks. It is worth noting that the prognosis for TOS is also very dependent on your ability to manage aggravating factors and perform self-management strategies.


It is important to get onto treatment for TOS early. Treatment typically involves pharmacological intervention (in the early stages), manual therapy (osteopathy) and self-management strategies. In the rare and more severe cases, a surgical opinion may be required, to assess the need for decompression surgery.


Medication is not always necessary, but can be a useful tool to address inflammation (including swelling) and pain. Medication may also provide relief to allow you to continue to perform your daily tasks.

Please consult your GP or pharmacists for advice regarding if/ which medication may be right for you.


Osteopaths have many tools in their belt that can help with the symptoms of TOS such as:

  • Address the muscles creating the compression

  • Help to restore normal range of motion in the neck, upper back, shoulder

  • Provide appropriate advice on posture, ergonomics

  • Give sport and activity specific modification advice

  • Prescribe appropriate muscle strengthening exercises and stretching

  • Give you the tools to help you manage your symptoms at home


There a few things you can do at home to help reduce your TOS symptoms, these include:

  • Practicing good posture and ergonomics at home and at work (especially for desk workers)

  • Avoid carrying heavy bags on your shoulders (think of the compression force going into the thoracic outlet area)

  • Be conscious of avoiding repetitive activties that flare up your symptoms

  • Stretching and strengthening exercises

Here is a bonus tip for those of you with TOS, which has occured as a result of compression from your scalenes and pectoral muscles - these are easy and effective exercises, which can be done at home, to help reduce to compression on your neurovascular structures, and therefore reduce your symptoms of TOS:

Scalene stretch:

  1. Hold down your collar bone with one hand

  2. Turn your chin away, and then down, towards the opposite shoulder (from the side that is held down)

  3. You should feel a stretch on the front of the neck of the side side that is held down

  4. Hold for 10-20 seconds, or until you can feel a release in tension

  5. Repeat 1-2 times and perform throughout the day

Pec stretch:

  1. Find a nice wall

  2. Make an L shape with your arm against the wall, by placing your elbow at shoulder height NB: Do not place your elbow above shoulder height

  3. Slightly turn your body away from the wall, until you feel a stretch in the front of your chest

  4. Hold for 10-20 seconds, or until you can feel a release in tension

  5. Repeat 1-2 times and perform throughout the day

  6. If placing your elbow on the wall is reproducing of your symptoms, try lowering the angle of your arm on the wall or doing the stretch with a straight arm again at a lowered angle. The stretch should not cause pain!


Retrain Health is based in the Northern Rivers, NSW. From our Byron Bay and Ballina clinics, our team provides a range of quality healthcare services and products.

Retrain Health offers osteopathy, remedial massage and strength and conditioning, and PT sessions with qualified practitioners.

If you are interested in finding out more information or would like to book an appointment, please contact the clinic by phone (02) 6680 7447, send us an email or click here to book an appointment online.

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