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How to Know If You Have Thoracic Outlet Syndrome
By Dr. Elliot Smithson, PT, DPT, MS, ATC, EMT·May 31, 2026
8% of the cases of RSI in the arm actually end up being thoracic outlet syndrome, so I wanted to put this megathread together to help people know what to look out for.
Think of your thoracic outlet as a busy highway system where important nerves and blood vessels travel from your neck to your arm. This highway has three major "tunnels" where traffic jams (compression) can occur:
The Three "Tunnels" of the Thoracic Outlet
The Scalene Triangle represents the first potential compression point. This space is formed by two neck muscles (the anterior and middle scalenes) and your first rib, creating a tunnel where a traffic jam can occur. When these muscles become tight from prolonged forward head posture, they can compress the important nerves and blood vessels passing through this space.
The Costoclavicular Space forms the second potential compression point. This area lies between your collarbone and first rib, creating a tight corridor that neurovascular structures must navigate. Poor posture, especially rounded shoulders and tight pecs, can narrow this space further and increase compression on these vital structures.
The Subcoracoid Space represents the final checkpoint. This passage runs beneath your pectoralis minor muscle, which often becomes tight in gamers and desk workers due to prolonged internal rotation of the shoulders. When this muscle shortens, it can create a pressing force on the neurovascular bundle passing underneath it.
The Posture Problem
Here's where your gaming or work setup comes into play. That forward head position you slip into during intense sessions? That’s caused by low endurance of your deep neck flexor muscles which are responsible for keeping your neck in an upright posture. This causes your scalene muscles to work overtime to try to pick up the slack to keep your head up. The scalene muscles are primarily movement muscles and aren’t designed to hold your neck upright all the time and they get tired and irritated which causes them to tighten down as a protective response.
Deep Neck Flexors Responsible for Keeping Your Neck In An Upright Posture
And those rounded shoulders from hours of sitting? That’s due to weak upper back muscles between your shoulderblades not being able to keep your uppper back straight due to low endurance which causes your chest muscles (especially the pectoralis minor) get increasingly tight.
Parascapular Musculature Responsible For Keeping Shoulders Back
Pec Major And Pec Minor Tighten Down With Rounded Shoulder Posture
If you have the double whammy of forward head and rounded shoulders, it’s called upper crossed syndrome and is the biggest predisposing factor for developing TOS in people that play or work in a seated position.
The Three Flavors of TOS
Thoracic outlet comes in three major flavors and much like ice cream you can have just one kind or a combination of all three. Unlike ice cream, none of them are delicious.
Recognizing Neurogenic TOS
Neurogenic TOS is the most common form, accounting for 90-95% of all cases. Patients typically experience tingling sensations and pain that radiates down the arm, most commonly effecting the nerves that go to pinky and ring fingers, but can effect any of the nerves in the arm so your symptoms may be anywhere below the shoulder. This occurs when the brachial plexus, which is essentially your arm's nerve superhighway, becomes compressed at one or more of the thoracic outlet tunnels. Think of it like bad wire management.
The Brachial Plexus Your Arm's Nerve Super Highway
The nerves are the wires that connect your skin and your muscles to your brain and vise versa. If those are pinched you are going to start feeling weird sensations linke numbness, tingling, and pain. The symptoms often worsen during gaming sessions or prolonged computer use. If the compression goes on for long enough you can also experience weakness in any of the muscle groups in the arm, which can also lead to overuse injuries.
Sensory Innervation of the Arm
Understanding Venous TOS
Venous TOS manifests through visible changes in your arm's appearance and sensation. The affected arm may become swollen and take on a bluish-purple tint due to compromised blood return through the compressed veins. You might experience a persistent feeling of heaviness in the arm, as if you've just completed an intense workout. This form of TOS is particularly concerning for competitive gamers who maintain static arm positions for extended periods.
Discoloration From Impinged Veins
Identifying Arterial TOS
Arterial TOS, while the least common, can be the most severe form. Your hand might feel unusually cold and appear pale due to reduced blood flow through the compressed arteries. You may notice weakness during gaming or work sessions and experience cramping with continued activity. You can also experience numbness and tingling due to nerves losing their blood supply. These symptoms tend to be more pronounced during intense work or play sessions when blood flow demands to the hands are higher.
Pale Skin From Impinged Arteries
Self-Assessment: Understanding Your Symptoms
While only a healthcare professional can provide a definitive diagnosis, there are several self-assessment techniques you can use to better understand your symptoms. Remember: these tests should never cause significant pain or discomfort - if they do, stop immediately and consult a healthcare provider.
Testing for Vascular TOS: The EAST Test
The Elevated Arm Stress Test (EAST)
The Elevated Arm Stress Test (EAST), also known as the Roos test, is particularly useful for identifying vascular compression:
Raise both arms up into a "stick-up" position, with elbows bent at 90 degrees
Slowly open and close your fists for 3 minutes
Watch for these signs of vascular TOS:
Significant fatigue or heaviness in your arms
Color changes in your hands (becoming pale or bluish)
Having to lower your arms before the 3 minutes are up
Numbness or tingling that develops during the test
Testing for Pec Minor Involvement: The Doorway Check
Pec Minor Test
The pectoralis minor muscle can often be a key player in TOS. Here's how to check:
Stand in a doorway with your arm positioned at shoulder height, elbow bent to 90 degrees
Place your forearm against the doorframe
Step forward through the doorway while keeping your arm in position
If you experience:
Tingling down your arm into your fingers
Heaviness or fatigue in the arm
Reproduction of your typical symptoms
This suggests pec minor involvement in your TOS symptoms.
Testing for Scalene Involvement: The Neck Rotation Check
Scalene Test
The scalene muscles in your neck can compress the thoracic outlet. Here's how to assess them:
Sitting comfortably, put your hand on the shoulde by the collarbone you are testing, gently tilt your head away from the symptomatic side
Add a small amount of rotation toward the same side as the tilt
Hold this position for 10-15 seconds
You might have scalene involvement if you experience:
Tingling or numbness that travels down your arm
A feeling of heaviness or fatigue in the arm
Recreation of your usual symptoms
Slight dizziness or visual changes (rare, but possible due to arterial compression)
Important Notes About Self-Testing
Remember that these tests are not definitive diagnoses - they're tools to help you better understand your symptoms. Multiple positive tests often provide more reliable information than a single test alone. Additionally:
Never force any position that causes pain
Stop immediately if you experience severe symptoms
Use these tests as a guide for discussion with healthcare providers
Keep track of which tests reproduce your symptoms and how quickly they develop
If you experience positive findings with any of these tests, it's worth consulting with a healthcare professional for a proper evaluation.
Taking Action: Your Recovery Toolkit
There are 3 main stratgies for addressing thoracic outlet syndrome
Thoraic outlet at it’s core is an endurance problem with tight muscle patterns forming as compensation for low endurance. Endurance training for the fatigued out postural support muscles, stretching for the tight overworked movement muscles cosplaying as postural support muscles, and nerve gliding to free up the entrapped nerves.
1. Endurance Training
If the compression site is at the scalenes these exercises are great for building the postural endurance of the deep neck flexors which will offload the scalene muscles.
Isometric chin tucks are a great place to start and can be done at your desk if you have a high backed chair with a pillow.
If you're looking for a more tryhard neck progression check out our video on the iron neck here.
For compression at the pec minor (the costoclavicular or subcorocoid space) building the endurance of the muscles of the upper back is critical
For shoulder blade strength Face pulls are a great exercise to start with
2. Strategic Stretching
Stretching the tight muscles entrapping the neurovascular structures is the second strategy for treating TOS effectively. Remember a stretch should never be painful but it’s pretty normal to feel some of your symptoms when doing this because you are stretching the muscles compressing those structures. The symptoms should not linger for more than a couple minutes after finishing the stretch though. If you’re uncertain about this it’s important to consult with a physical therapist to get a good gauge on how much is too much or you can flare the condition up.
If the scalenes are tight you can start with gently stretching them the same way we tested earlier.
Scalene Stretch Exercise Video
If the pec minor is tight the same doorway test we discussed earlier can also be done to stretch them out.
3. Nerve Gliding Exercises
Nerve glides can be done for any of the 3 major nerves that branch off from the brachial plexus and run down the arm (including the ulnar, median, and radial nerve), which glides you will want to do will generally vary based on where you are feeling the symptoms.
These exercises should be approached gently and like the stretches it’s normal to feel some symptoms but they can also flare up your symptoms if done too aggressively.
We typically recommend no more than 10 reps a day.
An example of a level 1 nerve glide for all the relevant nerves can be found here.
When Medical Attention is Necessary
Persistent numbness or tingling sensations that don't resolve with rest should prompt immediate medical attention. This constant neural irritation can indicate progressive nerve compression that may lead to permanent damage if left untreated.
Significant weakness in your arm or hand, particularly if it affects your ability to perform precise mouse movements or keyboard actions, warrants professional evaluation. This weakness could indicate severe nerve compression or vascular compromise.
Changes in your hand's color or temperature that persist even after position changes are concerning signs that require medical assessment. These symptoms suggest significant vascular compromise that could lead to more serious complications if not addressed.
Pain that consistently disrupts your sleep should never be ignored. Nighttime symptoms often indicate progression of the condition and may suggest the need for more aggressive intervention.
Symptoms that don't improve with basic ergonomic changes and rest require professional evaluation to prevent potential chronic issues. Early intervention often leads to better outcomes and faster return to normal activities.
Setting Up for Success: Ergonomics 101
Your gaming or work setup isn't just about performance; it's your first line of defense against thoracic outlet syndrome (TOS). Proper ergonomics can significantly reduce the risk of TOS by promoting optimal posture and reducing strain on muscles and nerves. Position your monitor so your eyes align with the top third of the screen, keeping your neck in a neutral position to prevent forward head posture. Ensure your keyboard allows for a relaxed elbow angle and a neutral wrist position, while your chair should be adjusted so your feet rest flat on the floor, with your thighs parallel to the ground. Place your mouse in front of your shoulder at the same height as your elbow, to minimize shoulder strain. When using a gaming controller, crafting on the couch, support your elbows and keep your wrists straight to avoid unnecessary tension using a pillow for support.
Valari Pillow
Custom-made gaming pillows like the Valari can be incredibly helpful. By focusing on these ergonomic principles of neutral, you create a space that supports your body and reduces the likelihood of developing TOS.
The 45-Minute Rule - Your next posture is your best posture
Think of your body like a race car - even Formula 1 cars need pit stops! Set a timer for every 45 minutes and take a 5-minute "pit stop" to:
Stand up and walk around
Do some shoulder rolls
Gentle neck stretches
Quick scalene stretches
Doorway pec stretches
Pro Tip: Use these breaks between matches or loading screens.
Is it Really TOS? Understanding Different Wrist Pain Patterns
When you're experiencing wrist pain or tingling, it's crucial to understand that not all hand symptoms are created equal. TOS can often be confused with other common conditions, but there are some key differences that can help you identify what's really going on.
When dealing with neurovascular compression syndromes it’s really important to understand how these issues present, typically impingement syndromes present downstream from the site of compression.
TOS vs. Carpal Tunnel Syndrome
Carpal tunnel syndrome occurs at the wrist, specifically in the carpal tunnel where the median nerve passes through. The symptoms are limited to the thumb, index, middle, and half of the ring finger. If you're feeling tingling in your pinky or the back of your hand, it's almost certainly not carpal tunnel. Carpal tunnel symptoms are often triggered by repetitive wrist movements, while TOS symptoms are more frequently related to posture and arm position.
TOS vs. Cubital Tunnel Syndrome
Cubital tunnel syndrome involves compression of the ulnar nerve at the elbow. This typically causes numbness and tingling in the pinky and ring fingers. While this can look like neurogenic TOS, cubital tunnel symptoms are usually triggered by bending your elbow for long periods (like holding a phone or sleeping with your elbows bent) or direct pressure on the "funny bone" area. TOS symptoms, on the other hand, are often brought on by positions that affect the shoulder and neck.
Understanding these patterns is the first step toward effective treatment. If you're unsure which pattern matches your symptoms, explore our free resources or consider a professional consultation.
Medical Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional for any health concerns.