Why can't we move each toe like we move our fingers?

Sir, I have edited the passage to make it more concise, with a richer narrative rhythm, and to remove repetition, in accordance with the standard writing style of Dân Trí Science magazine .

Anthropologist Steven Lautzenheiser recounts that one weekend, he visited the zoo in Knoxville, Tennessee, where he lives, and stopped by the chimpanzee enclosure.

Their breakfast was still scattered around the area. Ripley, a male chimpanzee, quickly picked up fruits and vegetables, sometimes using his nimble feet as if they were his hands. After eating, he continued to use his feet to grasp the fire hoses hanging around the enclosure, even skillfully holding pieces of straw and toys with his toes.

"I find myself feeling a little envious. Why can't humans use their feet like that, quickly and easily grasping things with their toes just like we do with our fingers?" he shared.

As a biological anthropologist, Professor Steven Lautzenheiser specializes in the biomechanics of the modern human foot and ankle. He applies the principles of mechanics of motion to analyze how forces act on the body and how humans have evolved throughout history.

According to him, muscles, the brain, and the evolutionary history of the human foot are key factors explaining why we cannot move each toe independently like our fingers.

Comparing a person to a close relative.

Humans belong to the primate group, the same family as apes such as chimpanzees. In fact, chimpanzees are our closest genetic relatives, sharing about 98.8% of their DNA.

Evolution explains why chimpanzees have flexible toes, while human feet are somewhat more "clumsy." Our distant ancestors likely moved similarly to chimpanzees, using both hands and feet for climbing and gripping. However, over time, humans transitioned to an upright, bipedal gait.

This change forced the feet to adapt to take on the role of maintaining balance and supporting the entire body when standing and moving. Therefore, the ability to move each toe independently became less important than ensuring stability while walking.

Conversely, hands have increasingly played a central role in characteristic human activities, especially in toolmaking and use. Over millions of years, fingers have become more flexible, allowing for sophisticated tasks such as writing, playing musical instruments, or operating electronic devices.

It can be said that human hands and feet have evolved in two different directions, serving entirely separate purposes.

Muscles that control the movement of fingers or toes

Evolution has created differences between hands and feet through adaptations in the structure of muscles, bones, and tendons, to better serve locomotion and balance. Anatomically, the two are quite similar: both have five fingers or toes and are controlled by a complex system of muscles and tendons.

The human foot has about 29 muscles, primarily used to support standing and movement. Meanwhile, the hand has about 34 muscles, many of which are responsible for fine motor skills.

The majority of muscles in the foot help lower the toes, as in tiptoeing, or raise them, as in walking on heels. These muscles also allow the foot to rotate slightly inward or outward, helping maintain balance on uneven terrain. These coordinated movements ensure we can walk and run steadily.

The big toe plays a particularly important role in propelling the body forward when walking, so it has its own distinct muscles. The other four toes do not have such independent muscle systems.

Several large muscles in the soles of the feet and calves control all four of these toes simultaneously. Because they share a common muscle system, they can still move but cannot function independently like fingers. The calf muscles also extend down the foot via large tendons, prioritizing weight-bearing and balance functions over performing small, precise movements.

Conversely, six main muscle groups control each finger, mostly located in the forearm and connected to the fingers by a system of flexible tendons. The thumb and little finger also have additional muscles to assist in gripping. This system is specialized for performing fine, controlled movements, such as writing or playing musical instruments.

Therefore, the greater number of muscles in the hands is only part of the reason. The difference in the degree of specialization and organization of the muscle system is the crucial factor that prevents the toes from functioning independently like the fingers.

Brain power allocation

To fully understand the difference between fingers and toes, one needs to look at the role of the brain. A crucial area called the motor cortex is responsible for controlling body movements. This area contains millions of neurons that act as "messengers," transmitting signals from the brain to the muscles.

In the motor cortex, the area and density of neurons in the fingers are significantly larger than in the toes. This allows the brain to send more detailed and sophisticated signals to the hands. This organization makes finger control require more neural activity, or in other words, consume more brain resources than toe control.

This prioritized allocation of tasks allows the fingers to perform precise and complex movements, while the toes primarily play a supporting and balancing role.

So, even though we can't use our legs as flexibly as Ripley the chimpanzee, we now have an explanation: the difference lies not only in the muscles but also in how the brain allocates control to each body part.