Hand Going Numb? Check Your Thumb – How the Relationship Between Your Hand and Wrist Movement Can Affect Your Carpal Tunnel Syndrome Symptoms (Part 1/2)

Author:  Dr. Colin Butler, DPT, ATC

 

Carpal tunnel syndrome is a collection of symptoms that most commonly appear in the thumb, index finger, and middle finger on the palm side of the hand.

The hallmark symptom is aching, tingling, or a loss of sensation in those three fingers specifically.

These symptoms most often occur because the median nerve is experiencing prolonged compression as it passes into the hand through the carpal tunnel. The carpal tunnel is a narrow passageway formed by bones and connective tissue near the wrist that also contains several tendons and muscles, along with the median nerve. Because this space is small, even subtle changes in position or tissue behavior can increase pressure on the nerve. (Figure 1).

The most common treatments I see recommended include prolonged static stretching of the muscles on the front of the wrist and forearm, active range of motion exercises for the wrist and hand in all directions, stretching of the thumb muscles, and tendon or nerve gliding activities.

What all of these interventions have in common is their shared goal of reducing compression on the median nerve. Nerves thrive on movement, blood flow, and adequate space. The intent behind these treatments is sound, which is why the surgical option for severe cases involves cutting the connective tissue that runs across the carpal tunnel to create more room for the nerve.

While there is nothing inherently wrong with these approaches, not all interventions produce the same effect. If the goal is to create space around the carpal tunnel, it is critical to consider the relationship between the position of the hand and the wrist. Many of the muscles and tendons that influence carpal tunnel pressure either cross through the tunnel or attach directly to the bones of the hand and wrist.

Static stretching primarily increases a muscle’s tolerance to being lengthened. According to current research, it does very little to change how muscles or tendons behave or function in daily movement (PubMed ID# 28801950). In addition, applying prolonged tension to a nerve that is already compressed can be similar to stretching an already tight rubber band. Increasing tension does not reduce stress on the structure and may actually worsen symptoms.

Rather than focusing solely on muscles that are labeled as tight, it is often more effective to focus on positioning the bones of the hand and wrist in a way that reduces tension on the nerve. This approach helps “unstretch” the rubber band and gives the median nerve more room to move freely.

The image below shows an example of a thumb that is internally rotated relative to the wrist, highlighted in yellow. The blue arrow shows a thumb that is better able to externally rotate relative to the wrist. (Figure 2)

Can you see how stretching the muscles of the yellow hand might produce a completely different result than stretching the blue hand?

Applying the same solution to two different presentations does not lead to the same outcome.

In the next part of this discussion, we will explore how to create a more effective strategy to improve space and movement around the median nerve. This approach may help reduce or eliminate carpal tunnel symptoms by addressing the specific presentation shown in the yellow hand.