14% of humanity no longer have this muscle: this is how evolution destroys the palmaris longus

news hardware 14% of humanity no longer have this muscle: this is how evolution destroys the palmaris longus

Evolution affects every species on this planet at one time or another. Although man has lived on this Earth for nearly 7 million years, he has had time to experience many changes. Today, it is the palmaris longus muscle that is about to go down in history.

For anyone wondering where the palmaris longus muscle is located, it’s very simple: place your arm on a flat surface and extend your palm; then join the thumb to the little finger – we ended up with a typical Italian hand gesture: the Che vuoi. If a tendon appears as in the photo, you are the lucky owner of a long palm.. If the orangutan uses this muscle effectively, humans, on the contrary, do not use it. And that’s partly why 14% of the population don’t have it anymore.

The evolution and example of lactose

When we talk about human evolution, we usually take the example of milk. 11,000 years ago, when livestock farming was born, humans started consuming milk out of hunger, although it harassed us (literally) like a kick in the stomach. Humans, like the vast majority of mammals, can consume milk during a very specific period of their lives. As they age, the ability to produce lactase (and break down the lactose) fades away.

About 7,000 years ago, evolution and chance began to spark one of the greatest genetic revolutions in history: the ability to produce lactase throughout life. In fact, it was such a useful mutation that it spread very quickly to a large part of the population, so much so that in the West it seems normal to us. Nonetheless today, only 35% of humanity can consume lactose without problems. It’s pure evolution in action and, of course, it’s not the only case: that of the long palm is almost even more counterintuitive. How can an entire muscle disappear?

The long palm: a holdover from a bygone era

In most humans, there is a muscle that originates from the medial epicondyle of the humerus and the fascia that covers it to insert into the palmar aponeurosis, which is called the palmaris longus or palmaris longus. However, its absence (whether congenital or postoperative) does not affect hand function.

In fact, surgeons have been using the tendon for many years. long palm to replace other tendons when they rupture: it’s easy to remove and, on top of that, it’s almost useless. It helps to flex the hand and tighten the palmar aponeurosis, but as it plays a very small role, the fact that he disappears has no important consequences.

But what is a useless muscle like that doing to our body? This is one of the big questions asked by experts in anatomy and evolution. It is clear that the palmaris longus is a remnant of an ancestor of our ancestors. However, humans are not the only primates in this case: chimpanzees, for example, also have it and do not seem to make significant use of it..

Nonetheless, other monkeys use (orangutans are the most obvious example), but this evolutionary and functional complex makes the usual explanations for its disappearance (a supposed “adaptation” to the fact that we don’t climb trees) it does not make sense. The theory that links their disappearance to an evolutionary response to our ability to work with our hands doesn’t seem very strong either.

A disappearance that is really just the logical continuation of things

The answer to this disappearance is, in fact, it couldn’t be more logical. If many people think that the evolution of Man stopped a long time ago, it seems that it is not quite so – and it is quite logical, after all.. Once a mutation occurs, natural selection does the rest.. If the example of the palmaris longus is the most striking – because it is visible to the naked eye – it is by no means the only change that has affected humans. One thing is for sure, the future still holds many surprises – and not always happy ones.

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