How A Thoracic Outlet Syndrome Diagnosis Is Made? | 3 Crucial Steps To Get It

Written by on June 30, 2022 — Medically reviewed by Mitch Torres (PT)

To get a thoracic outlet syndrome diagnosis, your doctor has to follow certain procedures first. These include taking your medical history, making a thorough physical assessment, and requesting specific tests according to your symptoms.

They will provide all the information necessary to make an accurate diagnosis. We’ll discuss each one in detail below, apart from things you should know regarding this condition.

This is what we’ll cover, tap on any of the bullets below to go straight to its section:

3 Steps in diagnosing thoracic outlet syndrome

1) Evaluating your medical history

Your doctor will gather information regarding your symptoms, other medical conditions, and your daily activities. You might also answer a health survey while you’re waiting in the clinic.

These data-gathering tools give your doctor an idea of what is going on with your affected arm. When it comes to thoracic outlet syndrome (TOS), your physician will pay particular attention to (1):

Congenital abnormalities

These are structural traits that are present at birth which may further narrow the gap within the thoracic outlet. Some examples include cervical rib, extra rib, or an additional scalene muscle.

Health and lifestyle factors

These are activities or conditions that might predispose you to TOS. Poor posture, obesity, and vigorous overhead movements are a few examples.

Previous injuries

Sometimes, a physical injury right onto or near the thoracic outlet compresses the structures that pass through it. A whiplash injury and fractured collar bone are a few instances.

Tell-tale thoracic outlet syndrome symptoms

There are 3 types of thoracic outlet syndrome, each one with specific symptoms.

The most common is neurogenic thoracic outlet syndrome.

It makes up 95% of cases. It is brought on by compression to a collection of nerves called the brachial plexus. That is why its symptoms are all nerve-related such as (1):

  • Arm numbness and tingling.
  • Headaches.
  • Electric-like arm pain.
  • Weakness.
Venous thoracic outlet syndrome makes for 4% of cases.

It’s common for males between the ages of 15 to 45 years involved in heavy lifting and overhead activities. It happens after an injury to the subclavian vein, causing symptoms such as (2, 3):

  • Bluish discoloration of the skin.
  • Arm blood clots.
  • Swollen arm.
The least common type is arterial thoracic outlet syndrome.

It accounts for only 1% of total cases. Athletes, occupational lifters, and those with a cervical rib are at risk. (1)

It happens because of compression to the subclavian artery, which leads to symptoms such as (3):

  • A pale appearance of your hands and fingers.
  • Weak or absent pulse.
  • Arm pain.

Pro-tip: Remembering the events on when and how your symptoms started help make this part of the exam much easier. Put the information on a piece of paper or phone for a faster recall.

2) Physical examination

After taking your medical history, your doctor will perform a physical examination. Some of the things your physician may do include (4):

  • Inspecting any difference in the size and color of your arms.
  • Looking for tender spots around your head, neck, and shoulder.
  • Symptom-provoking maneuvers to test nerve or blood vessel damage.
  • Nerve examination of muscle strength, reflexes, and sensation.
  • Blood flow tests of pulse strength and blood pressure.

The results of all these tests give an idea of which structure is being compressed. It may also tell the cause of your thoracic outlet syndrome and its severity. But just to make sure, your doctor could request the 3rd step of the diagnostic process.

Pro-tip: Wear comfortable clothing. This will make your arm easily accessible for physical tests.

3) Imaging tests

Imaging tests confirm both the type of TOS and the exact site of compression. The results of prior steps could influence which type of test your doctor will refer you to, such as (1, 2, 5, 6):

  • X-rays to look for bony abnormalities.
  • A chest CT scan to check potential blockages in blood vessels.
  • Magnetic resonance imaging, to evaluate the status of the brachial plexus.
  • Nerve conduction studies to check for nerve damage if any.
  • Ultrasound, to detect changes in blood flow during certain physical tests.
  • Venography and arteriography to identify structures compressing the veins and/or arteries in the thoracic outlet area.

Pro-tip: Some of these tests require you to stay still in an enclosed space for half an hour or so. While other tests use needles. Let your doctor know if you are afraid of any of the two so they could adjust their imaging referral accordingly.

Other conditions to rule out before making a diagnosis

Before making a final diagnosis, your doctor has to check for other conditions that also share symptoms with neurogenic, venous, or arterial TOS.

This is to rule out any other possibilities, therefore provide the right treatment. Common conditions that may be confused with TOS include (7):

  • Atherosclerosis.
  • Adhesive capsulitis.
  • Rotator cuff syndrome.
  • Cervical spine radiculopathy.
  • Fibromyalgia.

How do you get your thoracic outlet syndrome treated?

After the diagnosis is made, the next step is to alleviate your symptoms by reducing the pressure on your nerves and/or blood vessels.

The treatments will depend on which type of TOS you have. The most common are:

Home remedies

Although they might offer short-term relief, these remedies could make your daily life manageable. A few examples of home treatments include:

  • Heat therapy for pain relief.
  • Non-steroidal anti-inflammatory drugs (NSAIDs).
  • Self-massage to reduce pain.
  • Shoulder exercises and stretching to improve posture.
  • Transcutaneous electrical nerve stimulation (TENS) for pain.


Tight or extra scalene muscles could compress the brachial plexus, leading to neurogenic TOS. (2)

To remedy this, your doctor can inject either painkiller or botox right into your neck muscle. Both of these can temporarily relieve symptoms and muscle tension. (1)

The painkiller’s effect only lasts for 4 hours but does confirm that you do have neurogenic TOS. (1, 8) This could open the door for other treatment options to help you recover.

Meanwhile, botox’s effect lasts up to 3 months and goes well with physical therapy treatments. (8)

Physical therapy

This treatment option is one that your doctor will likely recommend, especially for those with neurogenic TOS.

Here, a physical therapist will work with you to improve your symptoms and posture through exercises and manual treatment. They could also teach you strategies like exercises that you can do at home to manage your symptoms.

Blood clot medications

Both types of vascular thoracic outlet syndrome are at risk of developing dangerous blood clots. Your doctor can prescribe two medications to combat this risk and avoid complications.

One is an antithrombotic drug, also known as blood thinners. This helps prevent blood clot formations.

The other is a thrombolytic drug. It helps dissolve blood clots that had a chance to form around your body.

Surgical treatment

This is the best option for both venous and arterial TOS. For neurogenic TOS, it becomes an option if 4 to 6 months of conservative care can’t improve symptoms. (1)

The surgery for all 3 types is called “thoracic outlet decompression.” Here, the surgeon removes the structure that’s causing the compression – either the bone or muscle.

Surgical widening of blood vessels could also be done right after to improve blood flow. (1)


Who would diagnose thoracic outlet syndrome?

The diagnosis of thoracic outlet syndrome should be done by a medical doctor. Like an orthopedist, neurologist, and/or vascular surgeon.

Does MRI show thoracic outlet syndrome?

Yes! Research shows that an MRI is capable of identifying the source of compression in the thoracic outlet. (9)

What mimics thoracic outlet syndrome?

Vascular types of thoracic outlet syndrome mimic Raynaud’s syndrome and vasculitis. While the neurogenic type resembles both carpal tunnel syndrome and multiple sclerosis. (7)

Conclusion: How to diagnose thoracic outlet syndrome?

There are three necessary steps in diagnosing thoracic outlet syndrome – your medical history, physical exam, and imaging tests.

Your medical history helps establish patterns and risk factors that lead to thoracic outlet syndrome.

A physical exam lets your doctor inspect what’s going on with your shoulder. Finally, imaging tests give a visual of what is causing your injury.

Sure, it could be quite a lengthy process. But having the right diagnosis guides you on which treatment you should go for and how long you will take to recover.


  1. 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
  2. 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
  3. Goshima, K. “Overview of thoracic outlet syndromes.” Up To Date. Retrieved on May 2022 from:
  4. Povlsen, Sebastian, and Bo Povlsen. “Diagnosing Thoracic Outlet Syndrome: Current Approaches and Future Directions.” Diagnostics (Basel, Switzerland) vol. 8,1 21. 20 Mar. 2018, DOI: 10.3390/diagnostics8010021
  5. Remy-Jardin, M et al. “CT angiography of thoracic outlet syndrome: evaluation of imaging protocols for the detection of arterial stenosis.” Journal of computer assisted tomography vol. 24,3 (2000): 349-61. DOI: 10.1097/00004728-200005000-00001
  6. Aralasmak, A et al. “MR imaging findings in brachial plexopathy with thoracic outlet syndrome.” AJNR. American journal of neuroradiology vol. 31,3 (2010): 410-7. DOI: 10.3174/ajnr.A1700
  7. Masocatto, Nilo Olímpio et al. “Thoracic outlet syndrome: a narrative review.” “Síndrome do desfiladeiro torácico: uma revisão narrativa.” Revista do Colegio Brasileiro de Cirurgioes vol. 46,5 e20192243. 20 Dec. 2019, DOI: 10.1590/0100-6991e-20192243
  8. Freischlag, Julie, and Kristine Orion. “Understanding thoracic outlet syndrome.” Scientifica vol. 2014 (2014): 248163. DOI: 10.1155/2014/248163
  9. Hardy, Alexandre et al. “Thoracic Outlet Syndrome: Diagnostic Accuracy of MRI.” Orthopaedics & traumatology, surgery & research : OTSR vol. 105,8 (2019): 1563-1569. DOI: 10.1016/j.otsr.2019.09.020

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