If you've taken every thoracic outlet syndrome test available and they all came back negative, but you're still experiencing nerve pain, numbness, and tingling down your arms and into your hands, you're not alone.

The problem might not be actual nerve compression at all, it could be trigger points.

There are seven specific trigger points in the upper body that can create TOS-like symptoms without actually compressing your nerves and blood vessels. These trigger points are consistently missed by doctors and therapists because they don't show up on standard TOS tests, yet they can cause the exact same pain patterns you'd expect from true thoracic outlet syndrome.

​In this comprehensive guide, I'll show you:

Before we dive into the specific muscles, you need to understand the mechanism behind how a trigger point in your shoulder can create pain all the way down into your hands and fingers.

The answer lies in something called fascia lines specifically, the superficial and deep arm lines.

Think of fascia lines as giant "super muscles" within your body that connect multiple individual muscles together. For example, the superficial arm line encompasses:

Instead of thinking of these as separate muscles, imagine them as one continuous muscle running from your chest to your fingertips.

When a muscle develops trigger points (those painful knots you can feel), it gets stuck in a contracted, shortened state. This creates tension throughout that entire muscle.

But remember—in the fascia line system, that muscle is connected to several other muscles in a chain. So when one muscle in the chain has tension, that tension travels throughout the entire fascia line.

This is why you might have a trigger point in your infraspinatus (a rotator cuff muscle in your shoulder) but feel pain and numbness in your arm, fingers, and hand.

The trigger point creates tension at one point in the chain, and that tension radiates through the entire connected system.

​Now let's look at the seven specific muscles where these problematic trigger points commonly develop.

The infraspinatus is a rotator cuff muscle located on the back of your shoulder blade (scapula). This muscle is constantly under stress, especially if you spend time reaching forward with your arms—which describes almost everyone's daily activities, from typing on a computer to driving a car.

Why It Gets Trigger Points:

Every time you reach forward, especially with internal rotation (like when you're typing or using a mouse), the infraspinatus is stretched and put into an eccentric position. This constant stretching and contraction leaves it vulnerable to injury and trigger point formation.

The supraspinatus is another rotator cuff muscle located right above the infraspinatus. This one is trickier to access because it sits underneath your upper trapezius muscles, and those tend to be tight and restrictive in most people.

​This is where we need to use a special technique called the passive contraction method.

Think of a muscle like a rubber band or a trampoline. When you stretch a rubber band tight, there's tension in it, and trying to push through the middle is very difficult. But if the rubber band is loose and slack, you can easily manipulate it.

Muscles work the same way. There are three states a muscle can be in:

When you actively contract a muscle—like when you flex your bicep—your nervous system activates the muscle fibers, creating tension and making the muscle hard. When you stretch a muscle, you're also creating tension by elongating it.

But when you passively contract a muscle—meaning the muscle is shortened but your nervous system isn't actively firing it—the muscle is "loose" even though it's technically in a contracted position. This is the state we want for accessing deep muscles.

How to Apply This to the Supraspinatus:

The pec major is a large chest muscle, and trigger points here are extremely common—especially in women, who often find it difficult to get this muscle properly worked on by therapists.

​Here's a cool trick: your hand is the perfect measurement tool for finding pec major trigger points, because our anatomy is proportionate to our own body.

The latissimus dorsi (lats) is your giant back muscle—and here's an interesting fact: it's the only muscle in your body that attaches the lower body to the upper body.

The great news is that when you work on the lats, you also work on trigger point #5 (serratus anterior) because they overlap in the same area.

How to Find It:

The trigger points are located where the lats insert into your upper arm bone (humerus), right underneath your armpit. This is also where the serratus anterior and lats overlap—a junction area that houses lots of trigger points.

As mentioned above, the serratus anterior sits on your ribs and overlaps with the lats under your armpit. You can target both muscles simultaneously using the same location and techniques described for the lats.

This is one of the most efficient trigger point releases because you're treating two problematic muscles at once.

The triceps is probably the most underrated and overlooked muscle when it comes to trigger points—yet it's one of the most commonly affected. Why? Because your triceps are constantly being used throughout the day in nearly every arm movement.

Tricep trigger point pain usually stays on the back side of your body. It can extend all the way down the posterior side of your arm to the back of your pinky and ring finger. But even if you're not feeling pain there, you might still have tricep trigger points affecting your overall arm function.

The final trigger point location is the biceps. Just like the triceps, your biceps are constantly used throughout daily activities, making them prone to trigger point development.

Interestingly, trigger points in the biceps can create pain in the front of the arm (which makes sense) but can also refer pain to the back of the shoulder near the infraspinatus area.

Now that you know about these seven trigger points, here's what you should do:

Press into each of the seven areas described above and note which ones are tender. Don't be surprised if you find 4-5 of them are problematic—this is very common.

These are likely your biggest problem areas. Begin your trigger point work here and spend 2-3 minutes per spot.

Trigger point release isn't a one-and-done treatment. You'll need to work on these spots regularly, especially if poor posture or repetitive movements are continually creating new trigger points.

​Recommended Frequency:

Static Pressure:

Micro-Movements:

Pin-and-Stretch:

For any deep muscle underneath a tight superficial muscle, put the outer muscle in a passive contraction first. This technique alone will allow you to access muscles you never could before.

While self-massage and trigger point release can be incredibly effective, some cases require additional intervention. Consider working with a qualified manual therapist or corrective exercise specialist if: