If your tendon raises when touching your pinky to your thumb, it’s due to the palmaris longus muscle, an evolutionary trait.
Tendon movement when touching pinky to thumb
Have you ever noticed a tendon popping up on your wrist when you touch your pinky to your thumb?
This unusual phenomenon happens due to the palmaris longus muscle, a part of your forearm.
It might seem strange, but it can reveal interesting facts about your body and even about human evolution.
What is the Palmaris Longus muscle?
The palmaris longus is a small muscle located in your forearm. It extends from the elbow to the base of your hand.
This muscle is not found in everyone. Some people have it, while others do not.
Its main function is to help with the movement of the wrist, and it is often considered a vestigial muscle.
That means it has lost most of its original function through evolution.
How does the Tendon rise up?
When you touch your pinky to your thumb, you engage the muscles in your forearm.
This action makes the palmaris longus muscle contract. As the muscle tightens, the tendon attached to it becomes more visible.
For people who have this muscle, the tendon might rise noticeably on the inside of the wrist.
This is because the muscle is pulling on the tendon, making it stand out.
Why some people don’t have this muscle?
Interestingly, not everyone has a palmaris longus muscle.
Research shows that about 10% to 15% of people do not have it in one or both arms.
This variation is linked to genetics and evolutionary changes.
In the past, this muscle was more crucial for activities like climbing and gripping.
Over time, as human activities changed, the muscle became less important, leading to its varying presence in people today.
Evolution and the Palmaris Longus
The presence or absence of the palmaris longus muscle is an example of how our bodies have evolved.
In our ancestors, this muscle played a bigger role in hand movements and climbing.
As humans evolved, our need for this muscle decreased. This is why some people have lost it entirely.
Why is it important to know?
Knowing about the palmaris longus muscle is not just a fun fact. It can be useful in medical contexts.
For instance, surgeons sometimes use this muscle for reconstructive surgeries.
If a person lacks this muscle, doctors might choose alternative methods for these procedures.
Also, understanding such evolutionary traits helps scientists learn more about human development and the changes in our anatomy over time.