If you’ve ever touched your pinky to your thumb and noticed a tendon rising up on your wrist, you might be curious about what it means. This visible tendon is connected to a muscle called the palmaris longus, and not everyone has it!
What Is the Palmaris Longus?
The palmaris longus is a small muscle that runs along the forearm and connects to the palm. It was once useful for our ancestors, likely aiding in climbing and gripping. Over time, as humans evolved and relied less on these functions, the muscle became unnecessary. As a result, some people never develop it at all.
Why Do Some People Have It and Others Don’t?
Studies show that about 14-20% of people are missing the palmaris longus in one or both arms. Whether you have it or not is purely genetic—it doesn’t indicate anything about strength or ability.
How to Check If You Have It
To test for the palmaris longus:
- Place your hand palm-up on a flat surface.
- Touch your pinky finger to your thumb.
- Slightly flex your wrist.
- If you see a thin tendon pop up in the center of your wrist, congratulations—you have a palmaris longus! If not, you’re among those who were born without it.
Does It Affect Strength or Dexterity?
Not at all! The palmaris longus doesn’t significantly impact grip strength or hand function. Many professional athletes, musicians, and surgeons don’t have it and perform just as well as those who do.
Why Do Doctors Care About This Muscle?
Surgeons often use the palmaris longus tendon in reconstructive surgeries, such as tendon grafts. Because it’s not essential, doctors can remove it without affecting hand function. This makes it a valuable resource for repairing damaged ligaments in the wrist or even for facial reconstruction procedures.
Fun Facts About the Palmaris Longus
- It’s more common in some populations than others. Studies suggest it’s missing in about 10% of Caucasians, 30% of Asians, and 40% of African populations.
- Some people have it in one arm but not the other!
- Other primates, like lemurs and monkeys, rely on this muscle for climbing, which suggests its ancient purpose.
Conclusion
If your tendon raises when you touch your pinky to your thumb, it just means you have a palmaris longus muscle—nothing more, nothing less! If you don’t see it, you’re simply part of the percentage of people who never developed it. Either way, it has no real impact on your daily life, so whether you have it or not, you’re perfectly fine!
