Thoracic Outlet Syndrome | Physio Explains Causes, Types, Treatments, And More!

Written by on April 24, 2022 — Medically reviewed by Mich Torres (PT)

Approximately 8% of the world’s population suffers from some form of thoracic outlet syndrome. (1) This condition can affect either a group of nerves or certain blood vessels.

So, each type of thoracic outlet syndrome has its distinct symptoms and treatment options. Identifying which form you have will give you an idea of what you can expect as you return to health.

You’ll learn all about this condition below. Here are the topics we’ll cover, tap on any of them to quickly jump into that section:

What is thoracic outlet syndrome?

Thoracic outlet syndrome (TOS) results from the compression of nerves or blood vessels as they pass through the thoracic outlet. It usually affects females between 20 to 50 years of age. (2)

Think of the thoracic outlet as a gateway. It helps connect the nerves of your neck and the blood vessels of your heart to your arm.

As it only has a narrow space, there are 3 sections where these structures are vulnerable to a compression injury (3):

Interscalene triangle

This is closest to your neck and looks, well, like a triangle. The sides are bordered by your scalene neck muscles and the base by your first rib. Your brachial plexus nerve and the subclavian artery pass through there.

Costoclavicular space

This section is surrounded by your first rib, scalene muscles, and collar bone. Your brachial plexus, subclavian artery, and subclavian vein all pass through this compartment as well.

Subcoracoid space

This is the farthest section from your neck. It’s bordered by your chest muscle, ribs, and a bony tip from your shoulder blade. Your brachial plexus and subclavian vessels all continue through this section.

What can cause a thoracic outlet syndrome?

Here are some common causes that can narrow or compress the important structures going through the thoracic outlet (3, 4):

Physical trauma

A collar bone fracture or a whiplash injury can reduce the space in any of the three spaces described above. These injuries often happen after motor vehicular accidents or falling onto an outstretched arm.

Repetitive stress injury

Repeatedly using your arm -in sports, hobbies, or at work- can make your muscle grow. But, this increased size may play a part in compressing your nerves or blood vessels, causing a thoracic outlet syndrome.

Poor posture

Some postures can reduce the space in the thoracic outlet.

Staying in them for too long on a daily basis and for an accumulated period of time can make you prone to thoracic outlet syndrome (4):

  • Hunched or rounded shoulders.
  • A head that tends to lean forward often.
  • Having a slouched upper back.

Structural irregularity

This can come from a congenital difference in your bony structure or from other diseases.

One example is having a cervical rib, which is present in 1 to 2% of the general population. (3) This means you were born with an extra rib and it grew right below your neck, adding more compression to the thoracic outlet.

Other instances include developing a tumor near the thoracic outlet and having an excess number of scalene muscles than normal.

Learn more: All the causes of thoracic outlet syndrome and their treatments.

What are the types of thoracic outlet syndrome?

There are two types of thoracic outlet syndrome:

1) Neurogenic thoracic outlet syndrome

A neurogenic TOS is the one affecting your nerves – the brachial plexus. This is a large network of nerves that control the muscles and sensation of your upper arm.

This type of TOS accounts for 95% of all cases. It usually affects those with a whiplash injury or with a cervical rib. (3)

It is further divided into two forms of TOS (2):

True neurogenic TOS

This is the rarest form of neurogenic TOS, usually affecting women. (2) Symptoms present on one side of the body and include (4, 5):

  • Progressive weakness of the hand muscles.
  • Pain/pins and needles/numbness from your inner elbow to your little finger.
  • Headaches at the back of your head.
  • Neck pain.
  • Loss of dexterity.
  • Intolerance to cold conditions.

Disputed neurogenic TOS

This one makes up 95-99% of all cases of neurogenic TOS and often affects both sides of your body. It presents the same upper arm symptoms as the true variant but with other unique signs, such as (2):

  • Facial pain.
  • Visual or hearing disturbances.
  • Vertigo.
  • Abnormally high heart rate.
  • Sleep disturbances.

2) Vascular thoracic outlet syndrome

This form of TOS affects the blood vessels of the thoracic outlet. As such, it’s further divided into 2 types (2, 3):

Venous thoracic outlet syndrome

3 to 5% of all TOS fall under this category. It’s more common among males, between the ages of 15 to 45, involved in heavy lifting and repetitive overhead work.

Venous TOS compresses the subclavian vein, a blood vessel that drains the blood from your arms back to your heart. That’s why symptoms typically affect your dominant arm and include (3):

  • Arm pain.
  • Recent arm swelling.
  • Bluish color of your skin.
  • Arm heaviness.
  • Blood clots in the arm after repetitive motions, also known as effort thrombosis.

Arterial thoracic outlet syndrome

Arterial TOS accounts for 1 to 3% of all cases. (3) It affects both genders equally, often in young adults. As with a neurogenic TOS, having a cervical rib is a risk factor. (3)

Arterial TOS compresses the subclavian artery, a blood vessel that supplies blood from your heart down to your arm.

As rare as this type of TOS may be, it’s also the most dangerous. This is due to the risk of poor blood supply to your arm, depriving those tissues of oxygen and nutrients. Symptoms include (2):

  • Arm pain.
  • Weak radial pulse with large arm movements.
  • An unhealthy pale appearance on your arm.
  • Weakness.
  • Fatigue.
  • Blood clot formation in the affected arm.

How is thoracic outlet syndrome diagnosed?

Your doctor will do the following to diagnose your condition:

Take the history of your symptoms

Here, the doctor will likely ask you about:

  • When your symptoms start.
  • If there is any difference between what you felt then and are experiencing now.
  • Any exacerbating or relieving factors.
  • Possible mechanisms of injury.

This step allows your doctor to identify patterns in your symptoms, guiding them later on as you go through your consultation.

Perform a physical examination

In this next step, your doctor will check your body movements and do a series of physical tests to check your affected arm. Your physician will pay particular attention to:

  • The posture of your head, neck, and shoulders.
  • Differences between muscle size, strength, skin color, and temperature between your good and affected arm.
  • Take your blood pressure in both arms to rule out vascular TOS.

Diagnostic tests

Your doctor might ask for other tests to increase the accuracy of your diagnosis. This includes (6):

  • Chest or cervical spine x-ray-
  • Angiography.
  • Venous dopplers.
  • Electrodiagnostic studies.

If all these steps point to a diagnosis of TOS, your doctor will recommend some of the following treatment options.

5 treatments for thoracic outlet syndrome

Fortunately, TOS responds well to nonsurgical treatments, resolving 90% of all cases. (6) Some of the factors that lead to good outcomes include (2):

  • Physical therapy compliance
  • Long-lasting postural and lifestyle changes
  • Having a sedentary job with few physical demands

While on the opposite side of the spectrum that can delay your recovery are (2):

  • Obesity
  • Prior trauma
  • Length and severity of symptoms
  • Depression

With that in mind, here are the top 5 treatments for thoracic outlet syndrome:

1) Home remedies

Ideal for: Mild forms of TOS.

Thoracic outlet syndrome treated with the following might help relieve your symptoms and avoid unnecessary stress on your shoulders (2):

  • Applying a heating pad to your injured shoulder for pain relief.
  • Massaging your shoulder muscles.
  • Improving your posture with upper body exercises.
  • Taking pain-relieving medications when needed.
  • Wearing shoulder braces to enhance your postural alignment.

These will be extremely helpful during flare-ups or for managing daily pain. However, there may not suffice for moderate or severe forms of this condition.

2) Injection therapy

Ideal for: Neurogenic TOS.

There can be times when tight scalene muscles can compress the brachial plexus. (2)

In this case, injecting pain-relieving drugs right into these muscles can provide symptom relief. If effective, it can also be a tool to help establish the diagnosis of TOS. (3) Some of these pain-relieving drugs include (2):

  • Botulinum toxin, also known as Botox.
  • Steroids and local anesthetics, like bupivacaine and lidocaine.

3) Thrombolytics

Ideal for: Mild venous or arterial TOS.

This type of drug helps dissolve blood clots that might have caused your symptoms, re-establishing blood flow to your arm. (2)

However, this might only be a temporary solution. If symptoms persist, you may need to undergo vascular surgery. (3)

4) Physical therapy

Ideal for: Neurogenic TOS.

For neurogenic patients, symptoms may have come from muscle imbalances around the upper body. Undergoing physical therapy can help fix that by:

  • Stretching tight muscles to improve their flexibility.
  • Various strength exercises to stabilize your joints.
  • Thermotherapy to make exercises more tolerable.
  • Teaching you postural mechanics and exercises you can do at home.

Results may not happen overnight, and you might have to go to physical therapy a few times per week. But through time and consistent effort, it can help prevent surgery.

5) Surgical treatment

Surgery is recommended in instances of (3):

  • Failure to show results with nonsurgical treatments after a trial of 4 to 6 months.
  • Uncontrolled pain or progressively arm weakness.
  • Venous and arterial TOS.
  • TOS with associated nerve injuries, like carpal tunnel syndrome.

Some form of decompression surgery may be performed to help relieve pressure. The good news is that for those who undergo this type of surgery, 90% of patients show significant improvement. (2)

Nonetheless, you’ll have to undergo post-operative physical therapy to help your body adjust and recover fully.

What are the complications of thoracic outlet syndrome?

If left untreated, TOS may lead to some of the following life-threatening conditions that warrant immediate medical attention:

Pulmonary embolism

Here, a blood clot gets dislodged and gets stuck on a blood vessel in the lungs. This in turn blocks blood flow to that area, lowering oxygen levels. This happens to about 10 to 20% of patients with venous TOS. (3)


In this case, a blood clot gets stuck on a blood vessel in the brain, restricting both blood flow and oxygen. This can severely impair physical and cognitive functions.

Limb ischemia

This condition results from arterial TOS. Due to the restriction of blood flow to your arms, muscles would be deprived of oxygen and nutrients. (7)

Venous gangrene

This happens when the body tissue dies due to a lack of blood flow. It’s another uncommon yet potential complication from a venous TOS. (7)

Phlegmasia cerulea dolens

It’s an exceptionally rare but severe form of thrombosis, where a blood clot gets stuck in a vein. Patients usually present with recent and massive arm swelling. The risk of amputation is very high. (2)

How can thoracic outlet syndrome be prevented?

As they say, prevention is better than cure. If you find that you are at risk to have TOS, or if you already had one before, here are simple tips to prevent it from happening again:

  • Schedule rest breaks at work to relieve muscle tension.
  • Arrange your workspace that supports good body posture.
  • Maintain a healthy weight.
  • Avoid carrying heavy bags which may promote poor posture.
  • Do your tasks efficiently by practicing proper body mechanics.
  • Consult your doctor right away if there are recent unexplained upper arm symptoms.


Is thoracic outlet syndrome serious?

It might be for venous and arterial TOS, so you need to get it checked by your doctor ASAP. For neurogenic, it is not life-threatening but may affect the quality of your life.

What are the symptoms of thoracic outlet syndrome?

Symptoms vary depending on what type of TOS you have. This can include neck pain, numbness to even blood clot formation in your arm. (2)

When is surgery necessary for thoracic outlet syndrome?

Vascular TOS requires immediate surgical treatment. (2) But for neurogenic TOS, failure of conservative treatments after a trial of 4 to 6 months may indicate a need for surgery. (3)

Conclusion: What does thoracic outlet syndrome mean?

Thoracic outlet syndrome is the compression of nerves and blood vessels between your neck and arm.

Its innately narrow passageway plus the structures surrounding it increases your vulnerability to this injury. Whichever structure gets compressed will influence your treatment options.

Contact your doctor or physical therapist to further guide you on your recovery.


  1. George, Elizabeth. “Chapter 8a – Thoracic outlet syndrome, do women present differently than men?” Vascular Disease in Women: An Overview of The Literature and Treatment Recommendations. Edited by Caitlin W. Hicks and Linda M. Harris. Academic Press. 2021, Pages 239-249.
  2. Li, Nathan et al. “Thoracic Outlet Syndrome: A Narrative Review.” Journal of clinical medicine vol. 10,5 962. 1 Mar. 2021, DOI: 10.3390/jcm10050962
  3. Jones, Mark R et al. “Thoracic Outlet Syndrome: A Comprehensive Review of Pathophysiology, Diagnosis, and Treatment.” Pain and therapy vol. 8,1 (2019): 5-18. DOI: 10.1007/s40122-019-0124-2
  4. Hooper, Troy L et al. “Thoracic outlet syndrome: a controversial clinical condition. Part 1: anatomy, and clinical examination/diagnosis.” The Journal of manual & manipulative therapy vol. 18,2 (2010): 74-83. DOI: 10.1179/106698110X12640740712734
  5. “Neurogenic Thoracic Outlet Syndrome.” Orphanet. 21 April 2022.
  6. Kaplan J, Kanwal A. Thoracic Outlet Syndrome. [Updated 2021 Apr 21]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from:
  7. Bryson, Maleese. “Paget-Schroetter Syndrome Secondary to Injury-Induced Thoracic Outlet Syndrome.” Journal of Diagnostic Medical Sonography, vol. 35, no. 3, May 2019, pp. 220–223,

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