What Is a Thoracic Outlet Syndrome Test?
A Thoracic Outlet Syndrome (TOS) Evaluation is a specialized, noninvasive vascular examination that evaluates blood flow to the arms and hands during different arm and shoulder positions. The study is designed to determine whether the arteries supplying the arm become compressed as they pass through the thoracic outlet—the narrow space between the collarbone, first rib, and surrounding muscles.
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Unlike routine vascular testing performed with your arms at rest, a Thoracic Outlet Syndrome Evaluation includes a series of provocative maneuvers, in which you will be asked to move your arms and shoulders into specific positions while blood flow is measured. These maneuvers help determine whether certain positions temporarily reduce circulation by compressing the arteries.
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The examination is commonly performed in patients who experience symptoms such as arm fatigue, pain, numbness, tingling, coldness, weakness, or color changes that occur when the arms are raised or used repeatedly. It can also help distinguish vascular Thoracic Outlet Syndrome from other conditions that produce similar symptoms.
Why Is a Thoracic Outlet Syndrome Evaluation Performed?
A Thoracic Outlet Syndrome (TOS) Evaluation is performed to determine whether blood flow to the arms and hands becomes reduced when the arteries are compressed as they pass through the thoracic outlet. Because this compression often occurs only in certain arm or shoulder positions, the examination measures circulation both at rest and during specialized positioning maneuvers.
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The study is commonly performed to investigate symptoms that occur when the arms are raised, extended, or used repeatedly. These symptoms may include arm pain, fatigue, numbness, tingling, weakness, cold hands, color changes, or a feeling of heaviness during everyday activities or overhead movements.
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Unlike routine vascular testing, a Thoracic Outlet Syndrome Evaluation is specifically designed to identify positional arterial compression. By comparing blood flow in different arm positions, the examination helps determine whether symptoms are related to vascular Thoracic Outlet Syndrome or another condition affecting the neck, shoulder, or upper extremities.
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The examination is also valuable for confirming a suspected diagnosis of vascular Thoracic Outlet Syndrome, evaluating the severity of arterial compression, planning treatment, and assessing circulation after surgical or other therapeutic interventions.
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Because the study provides objective measurements of blood flow during both resting and provocative maneuvers, it helps determine the presence, severity, and functional significance of arterial compression while guiding the most appropriate next steps in diagnosis and treatment.
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The examination is completely noninvasive, painless, and does not involve needles, injections, contrast dye, or radiation. It provides valuable information about upper extremity circulation while allowing you to return to your normal activities immediately after the study.
Common Reasons to Schedule a Thoracic Outlet Syndrome Evaluation
A Thoracic Outlet Physiologic Study is performed to evaluate blood flow and circulation to the arms during different arm positions using physiologic vascular testing, including Doppler waveforms, pulse volume recordings (PVR), and blood pressure measurements. You may benefit from this examination if you have symptoms or medical conditions that suggest vascular Thoracic Outlet Syndrome (TOS) or impaired circulation to the upper extremities.
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Suspected Thoracic Outlet Syndrome (TOS)
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Arm pain that worsens with overhead activities
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Numbness or tingling in the arm or hand
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Weakness or fatigue of the arm during use
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Coldness of the hand or fingers
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Color changes of the hand or fingers (pale, blue, or purple)
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Heaviness or aching in the arm with repetitive movements
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Symptoms that occur when raising or extending the arms
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Suspected arterial compression affecting blood flow to the arm
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Evaluation of abnormal pulses during arm positioning
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Follow-up of previously diagnosed vascular Thoracic Outlet Syndrome
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Monitoring after treatment or surgery for Thoracic Outlet Syndrome
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Evaluation of abnormal findings from a physical examination or another imaging study
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A Thoracic Outlet Physiologic Study uses noninvasive vascular testing to evaluate circulation during a series of arm positions and maneuvers. It is a safe, painless, and radiation-free examination that helps identify changes in blood flow caused by vascular compression, guiding appropriate diagnosis, treatment, and follow-up care.
What to Expect During Your Examination
A Thoracic Outlet Syndrome (TOS) Evaluation is a safe, painless, and noninvasive examination that evaluates blood flow to your arms and hands while they are in different resting and positioned states. The study typically takes 45–60 minutes, and you can return to your normal activities immediately afterward.
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During the examination, you will lie comfortably on an examination table while a vascular technologist places specialized blood pressure cuffs on your upper arms, forearms, and wrists. Depending on your symptoms, small cuffs or sensors may also be placed on your fingers to evaluate digital circulation.
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The examination begins with blood flow measurements while your arms are in a relaxed position. You will then be asked to move your arms and shoulders into several specialized positions, such as raising your arms, turning your head, or extending your shoulders. These maneuvers are designed to determine whether blood flow changes when the arteries pass through the thoracic outlet.
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During each position, blood pressure measurements, Pulse Volume Recordings (PVRs), and Doppler ultrasound assessments are obtained and compared with your resting measurements. You may experience temporary reproduction of your usual symptoms during these maneuvers, which can provide valuable diagnostic information.
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The examination is generally very comfortable. You may feel a brief squeezing sensation as the blood pressure cuffs inflate, but there are no needles, injections, contrast dye, or radiation involved.
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Once all measurements have been completed, the cuffs are removed, and your examination is finished. Your interpreting physician will review the results, and a report will be sent to your healthcare provider. If you scheduled your study as a self-pay patient, we will explain how and when your results will be communicated.
How to Prepare for Your Thoracic Outlet Syndrome Evaluation
A Thoracic Outlet Physiologic Study requires very little preparation. Following these simple instructions will help ensure your examination is completed comfortably and accurately.
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Before Your Appointment
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✓ No fasting is required. You may eat and drink normally before your examination.
✓ Continue taking your prescribed medications unless instructed otherwise by your healthcare provider.
✓ Avoid smoking, chewing tobacco, vaping, or using nicotine products for at least 2 hours before your appointment, as nicotine can temporarily reduce blood flow and affect the accuracy of the examination.
✓ Avoid caffeine for at least 2 hours before your examination, including coffee, tea, energy drinks, and caffeinated sodas, as caffeine may influence blood vessel function.
✓ Wear loose-fitting clothing, preferably a short-sleeved shirt, to allow easy access to your arms. You may be asked to remove jackets or bulky clothing during the examination.
✓ Avoid wearing bulky jewelry or accessories around your neck, shoulders, or arms, as they may interfere with cuff placement.
✓ Bring any previous vascular ultrasound, physiologic testing, CT angiography (CTA), MR angiography (MRA), or angiogram reports related to your arm circulation if they were performed at another facility.
✓ Arrive 10–15 minutes early to complete any necessary paperwork before your examination.
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During the study, blood pressure cuffs will be placed on your arms, and blood flow will be evaluated while your arms are moved into several different positions. This helps identify circulation changes caused by compression of the blood vessels at the thoracic outlet.
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A Thoracic Outlet Physiologic Study is a safe, noninvasive, and radiation-free examination that does not require contrast dye or injections. Following these instructions will help ensure the most accurate results.
Frequently Asked Questions
Q: What is Thoracic Outlet Syndrome (TOS)?
A: Thoracic Outlet Syndrome occurs when the nerves or blood vessels passing between the collarbone and first rib become compressed. This examination specifically evaluates the arteries to determine whether blood flow to your arm decreases in certain positions.
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Q: What symptoms can this examination help evaluate?
A: A Thoracic Outlet Syndrome Evaluation can help investigate symptoms such as arm pain, fatigue, numbness, tingling, weakness, cold hands, color changes, or heaviness that occur when your arms are raised or used repeatedly.
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Q: Will I have to move my arms during the examination?
A: Yes. You will be asked to place your arms and shoulders in several different positions while blood flow measurements are obtained. These positioning maneuvers are an important part of the examination and help determine whether your symptoms are related to positional arterial compression.
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Q: Is the examination painful?
A: No. Most patients experience only a brief squeezing sensation as the blood pressure cuffs inflate. Some of the arm positions may temporarily reproduce your usual symptoms, but the examination is generally well tolerated.
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Q: How long does the examination take?
A: Most Thoracic Outlet Syndrome Evaluations take approximately 45–60 minutes to complete.
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Q: Do I need to fast before the examination?
A: No. You may eat and drink normally before your appointment. There are no dietary restrictions for this examination.
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Q: Will I receive radiation or contrast dye?
A: No. The examination uses blood pressure cuffs, Doppler ultrasound, and physiologic blood flow measurements. There is no radiation, contrast dye, or injections involved.
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Q: Do I need a referral?
A: We welcome patients referred by physicians, nurse practitioners, physician assistants, and other healthcare providers. Self-pay patients are also welcome to schedule an appointment directly.
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Q: When will I receive my results?
A: Your examination will be interpreted by a qualified physician, and the results will be sent to your healthcare provider. If you scheduled your examination as a self-pay patient, we will explain how and when your results will be communicated.
Schedule Your Thoracic Outlet Syndrome (TOS) Evaluation
Whether your examination has been recommended by your healthcare provider or you are scheduling a self-pay vascular evaluation, our experienced vascular laboratory provides comprehensive, noninvasive testing to evaluate blood flow to the arms and identify positional arterial compression associated with Thoracic Outlet Syndrome (TOS).
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A Thoracic Outlet Syndrome Evaluation is a specialized physiologic examination that measures blood flow while your arms are at rest and in specific positions. If you experience arm pain, numbness, tingling, weakness, cold hands, or symptoms that worsen during overhead activities or repetitive arm movements, this study can provide valuable information about your circulation and help determine whether vascular Thoracic Outlet Syndrome is contributing to your symptoms.
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You can conveniently schedule your appointment online by selecting a date and time that works best for you. If you have questions about the examination or need help determining whether this is the most appropriate study for your symptoms, our team is happy to assist you.
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If you experience sudden severe arm pain, a cold or pale hand, sudden weakness, loss of sensation, or an inability to move your arm or hand, seek immediate medical attention or call 911 rather than scheduling a routine examination.
Why Choose Alpha Vascular?
Experienced Sonographer
Board-Certified Interpretation
Advanced Ultrasound Technology
