Things that Yoram knows: why do you need toes?

Jinjun wonders what the toes are for? Are they a useless organ destined to degenerate and disappear? And why is it so painful for them to hit a piece of furniture at night?

Let's start from the end: hitting the little finger hurts a lot because the finger is small. The force is applied to a small and isolated area so that the local pressure from the center of the finger is thin and there is no significant "cushioning" between the skin and the bone. Similarly, every parent knows that it hurts more to step on a Lego cube the smaller it is. But the pain also raises the deeper question: why do we need these fingers at all and should they disappear? It turns out Jinjun that the foot on the 26 bones and the abundance of muscles, ligaments and tendons in it is a very ancient structure that is beautifully preserved And unlike the wisdom tooth For example, there seem to be good reasons for this. Fossilized footprints discovered in Kenya, left by our ancestor Homo-erectus about a million and a half years ago, allow us to learn not only about the shape of the foot but also about the distribution of the load between its parts, that is, about the way of walking. It turns out that while the brain and other body parts have changed quite a bit since then, at the point of contact with the ground we remain very similar to our ancestors.

The feet and hands received a different direction in evolution

About 5 million years ago, when we adapted to standing upright, evolution began to act very differently on the hand and the foot, which are basically identical organs. When the hand was freed from the tasks of movement, the way was opened for it to become a precise device for handling tools. The foot has preserved the ancient function of movement and posture but the demands on it have changed. The ancestors of man were required to invent a new way of moving, the foot has to withstand the impact it absorbs with each step and at the same time it has to be flexible in order to adapt to different ground conditions and to maintain the balance of a body with a high center of gravity that rests on only two points of support. About 4 million years were required for natural selection to design a foot that would meet these unique requirements. The solution includes a hard heel - a kind of hammerhead that absorbs the impact of landing the body's weight on the ground. In order to carry the weight of the body, evolution turned to the architectural solution that was invented again and again in nature and culture - the arch. The front part of the foot and with it the toes that seem unnecessary to you satisfies the demand for flexibility, for adaptation to the surface and for assisting in the delicate task of stabilizing the body. As mentioned, the fossilized prints from Kenya show all the characteristics of the human step, the heel kicking, the rolling of the load forward on the outer side of the arch and the transfer of the weight to the cushion in the front of the foot and from there to the bases of the toes that detach from the ground: the same automatic series of movements that a one-year-old baby performs to the sound of his parents' cheers and that the chimpanzee did not will teach the world. It is this structure and function that allowed man the way of life based on long-distance walking in the open plains where the character of modern man (Homo sapiens) was shaped. 

And yet the question is not far-fetched: for some of humanity something happened recently that changed this old structure: the foot was wrapped in a shoe.

The invention of the shoe

It is difficult to determine when the shoe was invented, in the book of Genesis the boss makes sure to sew cotton but not shoes for his young children before the divorce from Eden. This is despite the fact that he immediately gives them a good reason not to walk around barefoot "Cursed is the ground before you... and thorns and thistles will grow up for you". Our ancestors made the journey out of Africa about 50 years ago barefoot, just as many of their descendants still do today. The first shoe, more precisely an 8000-year-old braided sandal was discovered in a cave in the state of Missouri in the USA, so that the frozen journey through the Bering Straits to the American continent was already made by ancestors born on the continent, apparently, with protected feet. Cave paintings including figures of people in leather boots that are about 15,000 years old were discovered in Spain, and there are those who speculate that the human ability to protect the foot from cold injuries was one of the advantages that eventually led to the victory of Homo sapiens over Neanderthal man when the European continent cooled. 

But the footwear had a more far-reaching effect: unlike the clothes that man learned to adapt to the body, the shoe adapted the body to it. In the Shabbat Tract it is told about a series of trials that the old Hillel goes through to test the limits of his patience, one of them is the annoying question presented to him in the middle of the shower before Shabbat "Why are the feet of Africans wide" and his calm answer "Because there is water between the feet of the water" teaches not only patience but Also about anatomical understanding: the human foot is a plastic organ that can be shaped. The extreme and cruel example is the deformation and reduction of the feet of girls in China through tight tying, but to a more moderate extent each and even more so each of us walks on a foot that is a kind of bonsai plant grown in a miniature "shoe pot".

A survey in the USA found that 88% of women wore shoes that were too small for their size and 80% had deformities related to this. When you compare the western foot to its sister in the barefoot world, it turns out that it is narrower and the big toe is pushed closer to its slimmer brother. The difference is not only in the shape, but also in the distribution of the burden between the parts of the foot: the distribution of the load in bare feet is more uniform, while in the foot that grew in shoes, most of the work is done in small areas in the heel, the front pad and the big toe. The shoe mechanically isolates the toes from the ground and neutralizes their role in the final part of the foot leaving the floor with each step. When comparing the way of walking in people who always walked barefoot compared to those who wore shoes from early childhoodYou will discover significant differences.

With us, the locked ones, the step is bigger, the knee bends less with each step, the heel hits the ground more forcefully and the pressure when the leg comes off is also stronger. It turns out that an adult wearing shoes will not return to barefoot even if he takes off his shoes, the characteristics of the step that were imprinted in childhood will remain with him so that he can be distinguished from someone who grew up as a barefoot child. Since the joints of the toes are exempt from effort with the footwear, the bones of the first joint of each toe degenerate compared to their counterparts in the bare foot. In this way, even in the absence of any archeological remains except for skeletons, it is possible to distinguish between bare feet and closed ones. The earliest skeletons that can be assumed to have worn shoes were discovered in China and are about 40,000 years old. Maybe they, too, looked at their feet and wondered what the purpose of these fingers were for, with which you can't grasp anything. And maybe, like Jerry Seinfeld Recognize their importance.

Thanks to Dr. Ian Gilligan for his help.

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More of the topic in Hayadan:

• Things that Yoram knows: why are the legs long?
• in bare feet
• The evolutionary leap from fins to legs was surprisingly simple