If You Have a Tendon Protruding From Your Wrist – This Is a Sign of..?
If You Have a Tendon Protruding From Your Wrist – This Is a Sign of..?
The Palmaris Longus is a muscle in the human forearm. However, this muscle is absent in fourteen percent of the population. It is believed that the Palmaris Longus is vestigial, and it is a leftover muscle from our tree-dwelling ancestors. Those who lack this muscle do not suffer from and hand or arm weakness, and have the same grip as those who do still have a Palmaris Longus. Because we no longer use this muscle to swing through trees, surgeons often dissect it to perform some reconstructive surgeries.
The Palmaris Longus is not the only leftover from long ago. Since the late 1800s, there have been some cases of human babies being born with tails! These tails did not contain bone but were able to be moved with the muscles inside of the tail. Removing the tail is a simple operation. Our ancestors use tails for balance, and since we now walk upright, we no longer need a tail to keep us from falling.
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A more common vestigial trait is the arrector pili. All humans maintain this attribute, and you’ll notice the proof of this every time you get goosebumps. When you’re cold, the arrector pili attempt to create some insulation by “puffing out” the hair on our bodies, which has evolved to be too short to really keep us warm. When we feel a rush of adrenaline, the arrector pili spring into action again in an attempt to make us appear larger than our enemies.
Have you ever met someone who could wiggle their ears? This, too, is a leftover. Like many modern animals, our ancestors may have been able to move their ears toward a sound in order to hear it with more accuracy. Of course, we have lost this ability over many thousands of years.
Other vestigial characteristics in humans include wisdom teeth, tonsils, and the appendix. In this YouTube video from Vox Observatory, you’ll learn more about the palmaris longus, those unnecessary ear muscles, goosebumps, and the palmar reflex, a powerful grip found in human infants. You’ll even learn a trick to see if you are one of the few without a palmaris longus!
Livescience.com Io9.gizmodo.com