Arterial Thoracic Outlet Syndrome: Symptoms, Causes, Treatments, & Prognosis

Arterial thoracic outlet syndrome is the least common form of thoracic outlet syndrome (TOS). It is a rare but severe condition which affects 1%-5% of TOS patients.

Arterial TOS is caused by artery compression below the clavicle. Common symptoms include tingling and discomfort in the fingers, hands, or arms. Surgery and chiropractic care are two common treatments.

What is arterial TOS?

Arterial thoracic outlet syndrome (ATOS) describes compression of an artery in the scalene triangle, between your clavicle bone and first rib. (The scalene triangle is one of 3 regions of the thoracic outlet: scalene triangle, costoclavicular space, and pectoralis minor space.)

Thoracic outlet syndrome, in general, refers to trauma within the thoracic region between your collarbone and first rib. There are 3 main types of TOS:

  1. Neurologic or neurogenic thoracic outlet syndrome — This common type of TOS is characterized by compression of the brachial plexus, a network of nerves that regulates sensation in your shoulders, arms, and hands.
  2. Venous thoracic outlet syndrome — This type of TOS occurs when a subclavian vein is compressed.
  3. Arterial thoracic outlet syndrome — This uncommon type of TOS refers to the compression of the subclavian artery, resulting in aneurysms or occlusions.

ATOS specifically can lead to blood clots (thrombus) in the subclavian artery (beneath the clavicle). These blood clots may break off and progress down your arm. In the most serious cases, these blood clots can travel into the lungs, resulting in pulmonary embolism, which is potentially deadly.

How rare is arterial TOS? Arterial TOS is very rare. Lower estimates put the incidence rate of ATOS at less than 1% of individuals dealing with general TOS. However, it may occur in as many as 5% of general TOS patients.

Arterial TOS is observed at a higher-than-average rate in overhead-throwing athletes, like baseball pitchers.


What are the symptoms of arterial TOS? The symptoms of arterial TOS include the following:

  • Hand pain, often sudden pain with use (claudication)
  • Numbness in fingers or hand
  • Pins and needles in fingers or hand
  • Discoloration or paleness in fingers
  • Cold fingers, hands, or arms
  • Little blood clots in the fingers
  • Wounds in fingers that just won’t heal
  • Weakened grip
  • Constant fatigue in arms
  • Shoulder pain
  • Painless mass in neck
  • Blood clots that block blood flow (thrombosis)

ATOS may also be asymptomatic, but it still requires treatment.

Arterial TOS is the most dangerous form of TOS. Without treatment, ATOS can lead to serious health complications — potentially life-threatening.

Causes & Risk Factors

Arterial TOS is caused by an aneurysm (widening) or stenosis (narrowing) of the subclavian artery (the major blood vessel beneath your clavicle bone). If a blood clot forms then breaks off, it could block a distal artery, resulting in ATOS symptoms like pain and numbness.

Below are the greatest risk factors that don’t always result in ATOS but greatly increase your risk of developing ATOS:

  • Being born with an extra rib (cervical rib)
  • Constant overarm motion, such as pitching baseballs or swinging tennis rackets
  • Repetitive trauma to the subclavian artery
  • Female gender
  • Pregnancy
  • Age 20-50
  • Obesity
  • Chronic poor posture, including while sleeping
  • Anatomic abnormalities or bony anomalies in the thoracic outlet


ATOS can bring on sudden and severe symptoms. A healthcare professional should diagnose ATOS right away. Here’s what a diagnosis might look like, step by step:

  1. Discussion: Your doctor should ask about your list of symptoms, personal medical history, family medical history, and any history of injuries or repetitive arm use.
  2. Hand/finger/arm examination: Your healthcare provider should identify decreased blood flow to your arm. That might start with a physical examination, like checking your wrist pulse. A visual examination can identify pale fingers or a painless neck mass, both of which indicate ATOS.
  3. Thoracic examination: Your doctor should check the space between your clavicle and top rib (thoracic outlet) for arterial compression or injury. This might include checking for tenderness before ordering imaging tests.
  4. Urgent imaging tests: Your healthcare provider may order imaging tests (e.g., vascular lab study, catheter-based arteriography, MRI or CT angiography, x-rays, or ultrasound) to look for arterial blood clots.
  5. More imaging tests: After taking care of any clots, other (less urgent) imaging tests can examine the thoracic outlet for arterial compression, dilation, or narrowing.

You may want to ask your doctor what nonsurgical treatments and lifestyle changes may improve your symptoms while you wait for follow-up appointments.

Treatment Options

The most common treatment options for ATOS include:

  • Receive spinal adjustments from a qualified chiropractor
  • Go to physical therapy to strengthen your thoracic outlet region
  • Botox injections
  • Remove blood clots (thrombolysis) with anticoagulation medication like warfarin or heparin or with endovascular or vascular surgery.

For severe cases of ATOS, further surgical intervention may include:

  • Remove first rib(s), partly or wholly, to allow thoracic outlet decompression
  • Remove anterior scalene muscle(s) in the neck (AKA scalenectomy)
  • Replace damaged artery with healthy artery tissue or artificial tube

Most patients can expect to return to normal life after successful treatment without much change to quality of life.

For anyone with restricted blood flow to the arms (upper extremity ischemia), immediate surgical removal of blood clots may be necessary.

Does arterial TOS require surgery? No, arterial TOS does not always require surgery, but surgery is a common and effective treatment, such as first rib resection. More conservative treatment usually precedes surgical intervention. Symptomatic ATOS may require immediate surgical decompression. Prevention methods may mitigate the need for surgical treatment.

Preventing Arterial TOS

Here are the best ways to prevent arterial thoracic outlet syndrome:

  • Maintain a healthy weight.
  • Avoid overhead arm motions.
  • Exercise regularly, especially to strengthen your shoulders.
  • Don’t carry heavy objects with one arm or over one shoulder.
  • Stretch your chest, shoulders, and arms every day.

If you’re already showing symptoms of ATOS, you likely need immediate treatment. The presence of symptoms indicate the condition has progressed too far for prevention methods alone to replace treatment.

Potential Complications

Arterial thoracic outlet syndrome is a highly dangerous type of TOS. Untreated ATOS can lead to these potential health complications:

  • Severe blood clots
  • Wounds that never heal
  • Loss of fingers
  • Gangrene
  • Stroke, in severe cases

Long-Term Outlook

The long-term outlook for ATOS is good with an early diagnosis.

What is the prognosis for arterial TOS? Without treatment, ATOS may result in major blood clots, loss of fingers, and stroke. Fortunately, ATOS treatment is often successful, and early treatment usually leads to recovery.

Treat TOS at its root with upper cervical chiropractic.

Ready to get to the root of your problem with chiropractic care? We’re currently accepting new patients at our Ball Ground and Atlanta/Decatur offices.


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