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    Not To Alarm You, But You Might Be Completely Missing This Muscle In Your Wrist

    Okay, this is really weird.

    By now you're no doubt aware that no two people are exactly alike. Everyone has their differences, features, and traits that make them unique.

    An old man using the computer

    But what you might not know is that those differences can run deeper than you might think.

    Take, for example, the palmaris longus. The palmaris longus is a muscle that runs from the elbow down to the palm. Functionally, this muscle makes it easier for the hand to grip things.

    A diagram of a muscles in the arm with the palmaris longus labeled in the center of the wrist and the forearm

    It becomes most visible in the wrist. Here's mine:

    The palmaris longus visible in the wrist

    This very same muscle is present in cats, and much like a human's grip, cats rely on the palmaris longus to retract their claws.

    A cat's paw gripping a piece of wood with their sharp claws out

    Alright already! What's so special about this muscle? Why do I keep going on and on about it? — I'm glad you asked: 14% of all people DO NOT have this muscle.

    Some people only have it in one arm and not the other, while others don't have them in either arm.

    Here's how to check if you have it.

    Here's my hand at rest. Though you can sort of make out my palmaris longus in this photo, that won't necessarily be the case for everybody...

    My arm, palm up, hand open

    ...but when I touch my thumb to my pinky, my palmaris longus becomes much more pronounced.

    The palmaris longus sticking out of my wrist

    You seein' what I'm seein'?

    A closeup of the same photo

    Here's what it looks like when someone who doesn't have a palmaris longus does the exact same thing:

    A wrist doing the same flex, but it's flat

    So, are you one of the people with this muscle in your wrist?

    A closeup of a very pronounced palmaris longus

    See it?

    A palmaris longus on a different arm

    There it is!

    Do you have this muscle in your wrist? 5% of you don't, and a good portion of you have it in one but not the other.

    Twitter: @phreakery

    Embrace your tree-climbing past:

    If this tendon appears in your wrist when you hold your thumb and little finger together, you have a vestigial muscle called the PALMARIS LONGUS in your arm that helped our evolutionary ancestors climb trees. Because humans have no need for it now, 15% of people don’t have it.

    Twitter: @HaggardHawks

    And laugh at those 14% who don't have it. Good luck climbing trees!

    When you flex your wrist, does a muscle pop out? Not all humans have the palmaris longus muscle! Do you? #bioanth #funfacts #science

    Twitter: @BioAnthFunFacts

    Flex your wrist and see if you have it:

    The palmaris longus with a big circle around it

    And let us know whether or not you were blessed with this extra muscle:

    So there's this muscle called the Palmaris longus that's in your wrist and about 14% of people don't have it... I have it in my left wrist but not my right!!!!... Yes these are the things I think about at night when I should be sleeping...

    Twitter: @SuperJoshiYoshi