Why does the thumb only have two sections What does it do

When Australopithecus evolved into humans, their thumbs became very thick and powerful due to the frequent use of tools in their hands. In the palm of the human hand, some well-developed thenar muscles are also produced, allowing the thumb to move in tandem with the other four fingers opposite. It is as a result of this evolution that the thumb of modern humans has become the most powerful finger.

Why is there only two segments of such an important thumb, scientists believe that this structure is most suitable for it. Because if the thumb is only composed of one section, it is very inconvenient to grasp objects with the other four fingers; If it is three sections, then it will appear weak and incapable of some powerful movements.

Our ancestors, Australopithecus, used their limbs to climb up and down trees and pick fruits. At that time, the thumb, like the other four fingers, had three knuckles. This structure makes it easy to grasp the trunk and allows the ape to move flexibly between the branches.

Later, a part of Australopithecus learned to walk upright. The main function of the upper limbs has changed from climbing to using tools. The evolution of a long period of time has given us a clear division of labor for each of our fingers.

You don't see that the thumb has only two segments, but it is the most powerful of the five fingers. If the thumb has three segments like any other finger, it will not be able to perform a large force operation. The two-segmented thumb can be combined with the other four fingers to perform a variety of hand movements, and can also work independently.

Its function accounts for 40% of the function of our entire palm! Without it, there are many tools that we wouldn't be able to use. Imagine:

How do you use scissors without a thumb?

So where did the third finger of the thumb go? In fact, if you look at the X-ray photos of the hand bones, you will find that the original third finger gradually moves towards the palm and becomes the "metacarpal bone" connected to the palm.

This structure of the thumb is one of the logical results of the evolution from ape to man, because if the thumb is composed of only one section, it is very inconvenient to grasp objects with the other four fingers; If the thumb is three-segmented, then it will appear weak and unable to perform some powerful movements.

A human hand has five fingers, which vary in length, thickness, and thickness, and each finger has its own name: thumb, index, middle, ring, and little finger. Interestingly, the index finger, middle finger, ring finger, and little finger are all divided into three segments, but the thumb has only two segments.

According to the theory of evolution, it is already known that man evolved from Australopithecus. Australopithecus lived in forests and crawled on all fours, with the thumb or big toe separated from the other four fingers (toes), and when climbing in trees, it was very useful to have three fingers or toes, while only two thumbs (toes) were of little use. Later, the apes learned to walk upright, and their upper limbs were liberated, especially after they evolved into humans, and their thumbs became very thick and powerful due to the frequent use of tools in their hands.

In the palm of the human hand, a large thenar muscle is also produced, so that the thumb can cooperate with the other four fingers on the opposite side. It is as a result of this evolution that the thumb of modern humans has become the most powerful finger. The idiom is second to none and means the most outstanding, which means the thumb.

Indeed, according to scientists, almost more than half of all jobs that involve finger movement require thumb help. The thumb can work independently and in collaboration with the other four fingers, such as writing, holding chopsticks, holding a gun, etc. Why is there only two sections for such an important thumb?

Scientists believe that this structure is most suitable for it. Because if the thumb consists of only one section, it is very inconvenient to grasp objects with the other four fingers; If the thumb is three-segmented, then it will appear weak and unable to perform some powerful movements. Therefore, this structure of the thumb is one of the reasonable results of the evolution from ape to man.

1. According to the theory of evolution, it is already known that man evolved from Australopithecus. Australopithecus lived in forests and crawled on all fours, with the thumb separate from the other limbs, and only two thumbs of little use, but commanding.

2. It is the result of this evolution that the thumb of modern humans has become the most effective finger. The meaning of the idiom "second to none" is to refer to the thumb.

3. There are only two segments of such an important thumb, and scientists believe that this structure is most suitable for it. Because if the thumb is only composed of one section, it is very inconvenient for it to cooperate with the other limbs to grasp my objects.

4. If the thumb is three-segmented, then it will appear weak and powerless, and it will not be able to perform some powerful movements. Therefore, the structure of the thumb is one of the reasonable results of the evolution from ape to man.