The human body is nothing short of extraordinary. It’s a living testament to the wonders of natural evolution, though many of us rarely stop to appreciate just how remarkable our existence truly is.
Think about it: over millions of years, we’ve evolved from creatures resembling modern chimpanzees to the highly intelligent, complex beings we are today—building advanced societies, harnessing technology, and even sending spacecraft to other planets. And while this evolution has happened in what feels like the blink of an eye when viewed against the vast timeline of the universe, our journey is far from over.
What’s even more fascinating is that while humans today are nearly identical to our ancestors of 20,000 years ago, we live in a world that is almost unrecognizable from the one they inhabited. Yet, evolution never stops. Though the process unfolds over countless generations, its effects are still shaping us, often in ways we don’t immediately notice.
One such subtle shift is happening right now in the anatomy of our wrists, and it’s a curious example of how our bodies continue to adapt to our ever-changing lives.
The Tendon and Its Evolutionary Journey
The tendon in question is connected to a muscle called the palmaris longus. This muscle, though largely redundant in modern humans, once served a vital function for our ancestors—and still does for certain animals today.
The palmaris longus is most important for creatures that rely heavily on their forearms for movement. For example, lemurs, monkeys, and other tree-dwelling animals use this muscle to swing effortlessly from branch to branch. It grants them enhanced grip strength and flexibility, making it an essential part of their survival toolkit.
But here’s where it gets interesting: ground-dwelling apes, like gorillas, have gradually lost the need for this muscle as their modes of movement evolved. Since they no longer depend on their forearms in the same way, the palmaris longus has diminished over time.
Similarly, in humans, this muscle—and the tendon connected to it—is slowly becoming obsolete. Research suggests that somewhere between 10-15% of people no longer have the tendon at all, marking a small but significant step in our evolutionary journey.
Why Is It Disappearing?
The gradual disappearance of the palmaris longus tendon is a classic example of how evolution prioritizes efficiency. As humans transitioned from climbing trees to walking upright and using tools, the muscle became less necessary. Over generations, the body has begun to phase it out in some individuals.
Of course, evolution works slowly, so the majority of people—roughly 85-90%—still have the tendon today. But evidence points to its continued decline. This slow shift reflects how our bodies adapt to changing needs and environments, even in the absence of immediate threats or challenges.
How to Check if You Have the Tendon
Curious to know if you still have this evolutionary relic? Fortunately, there’s a simple test you can do at home.
- Place your forearm on a flat surface with your palm facing up.
- Touch your pinky finger to your thumb.
- Slightly lift your hand off the surface while keeping the fingers in this position.
Once you’ve done this, take a look at the middle of your wrist. Do you see a raised band running down the center? If so, congratulations—you still have the tendon!
If you don’t see it, you’re part of the growing percentage of people whose bodies have evolved beyond the need for the palmaris longus tendon.
What Does It Mean If You Don’t Have It?
Before you start wondering if you’re missing out on some important function, rest assured that the absence of the tendon doesn’t affect your strength or dexterity. In fact, many surgeons use the palmaris longus tendon for reconstructive procedures because removing it has no noticeable impact on a person’s overall hand or wrist function.
The lack of this tendon simply means that your body is adapting to modern life, where swinging from trees or relying heavily on forearm strength is no longer necessary.
Why It’s Fascinating
What makes this small anatomical detail so fascinating is how it connects us to our evolutionary past. The palmaris longus tendon is a reminder of the incredible journey our species has taken—from climbing through dense forests to building skyscrapers and exploring outer space.
It’s also a glimpse into the future. As our lifestyles continue to evolve, so too will our bodies. Perhaps in another few thousand years, the palmaris longus tendon will be gone altogether, a distant memory of a time when humanity’s survival depended on different skills and strengths.
Share Your Discovery
So, did you try the test? Do you still have the tendon? Let us know! Whether you’re among the majority who still possess it or part of the growing minority who don’t, this simple test offers a fun way to explore the ongoing story of human evolution.
If you found this fascinating, share the article with your friends and family so they can check for themselves. It’s a small but meaningful way to connect with our shared history—and maybe spark a conversation about where we’re headed next.
