Living beings evolve, all living species do, although the results are only seen with the passage of time. The human being evolves as a system of adaptation to the environment in which he lives. Thus, it is the case of the disappearance of a part of our body that we hardly use, the palmaris longus muscle. It is a tendon in the arm that primates have and that, in some of them, is very useful. 14% of people have already lost it.
The palmaris longus muscle is disappearing in humans. Do you have it?
You can check it in a simple way, just place your arm with your palm facing up on a smooth surface. Join your little finger with your thumb. If a tendon appears on your arm that sticks out to the naked eye, you have it. Otherwise, you belong to the 14% of the population that has evolved.
What is evolution? The best example can be seen with milk. More than 10 thousand years ago, the first livestock farmers began to consume milk from other animals. The reason is trivial, food was scarce and milk was a good food available to them.
However, most humans could not tolerate milk. As the mammalian organism grows, it loses the ability to break down the lactase present in breast milk.
With evolution, and over 7 thousand years, humans developed a way to break down lactase so they could drink milk throughout their lives. However, this revolutionary mutation that marks a milestone in evolution is not for everyone. Only 35% of the world’s population can drink milk their entire lives without digestive problems.
Why is the palmaris longus muscle disappearing?
In the case of the palmar longus, its disappearance is due to lack of use. It arises from the medial epicondyle of the humerus bone and inserts into the palmar aponeurosis. It has a complex name and description, but it is not commonly used, and we do not notice its absence.
For this reason, the palmaris longus tendon is frequently used in surgery, to replace other tendons when they rupture. This does not bring any consequences to the movement of the hand, and is the best solution.
For anatomy experts, the presence of this muscle is a vestige of some ancestor in the human evolutionary chain. All primates have it, although some of them do not use it either. Chimpanzees, for example, have almost no use for it. On the other hand, orangutans do use it frequently. Likewise, the lemur is the primate that has the “longest” palm.
The truth is that many theorists of humanity say that the evolution of man stopped a few centuries ago. However, the fact that a muscle disappears in more than 10% of the world’s population is a demonstration that it has not stopped. Evolution occurs slowly and takes millennia to manifest through a mutation or something tangible. It’s just a matter of waiting.