🧬 Why Do We Have It? (A Glimpse into Evolution)
This muscle is a vestigial remnant—a leftover from our primate ancestors.
In tree-dwelling primates, the palmaris longus helped with gripping branches and climbing.
As humans evolved to walk upright and use tools, the muscle became functionally obsolete.
Over time, natural selection didn’t eliminate it entirely—so it persists in most people as a harmless anatomical quirk.
🌍 Fun fact: The absence rate varies by population:
~10–15% of people globally lack it
Up to 25% of some Asian populations are missing it
Only ~5% of Indigenous Australians lack it
🩺 Why Do Surgeons Care About It?
Because it’s non-essential, the palmaris longus tendon is often harvested for grafts in reconstructive surgery—like repairing damaged tendons in the hand, face, or even ACLs in the knee.
If you ever donate tissue, this might be the tendon they take—and you’ll never miss it.
✅ How to Test for It (Try This Now!)
Rest your forearm on a table, palm up.
Touch your thumb to your pinky.
With your other hand, gently press just above your wrist crease.
If you feel or see a tendon rise, you have it!
If the area stays flat—you don’t. Both are perfectly normal.
💡 Note: Some people have it in one arm but not the other!
❓ Common Questions, Answered
Q: Does lacking this tendon affect strength?
A: No—studies confirm zero impact on grip or wrist function.
Q: Can it cause pain?
A: Rarely. In very few cases, it can contribute to carpal tunnel-like symptoms, but this is uncommon.
Q: Is it genetic?
A: Yes—the presence or absence is inherited.
💬 Final Thought
Your body is full of quiet echoes from the past—little evolutionary souvenirs that remind us where we’ve come from.
The palmaris longus isn’t useful today… but it’s a living link to our ancestors who swung through forests and gripped vines with every fiber of their being.
So next time you make that thumb-to-pinky gesture, take a moment to appreciate this tiny thread of human history—whether you have it or not.
“We carry the past in our bones—even when it no longer serves us.”
Did you find your tendon? Or are you part of the 15% without it? Share your result below—we’re all marveling at the wonder of the human body together! 🤲✨
