What does it mean to know what it means to have a hand

From the anatomy of the hand, the hand is divided into two parts: the bone and the muscle. Bones include carpal bones, metacarpal bones, and phalanges. There are 8 carpal bones, all of which are small short bones, arranged in two columns.

Right; There are 5 metacarpal bones and 14 phalanges forming nearly 30 joints, about 40 muscles that are in charge of the flexion and extension of the fingers and wrists, and their nerve endings are extremely rich, coupled with the participation of the joints of the upper limbs, which constitute the most complex interval of the human body, and each joint in this interval has its effective function. The utilization rate of ordinary people is only 30%, and the utilization rate of pianists and craftsmen is 50%. The main function of the hand is to complete nearly 100 kinds of actions such as pushing (finger pushing, finger wrist pushing, finger wrist pushing), pulling (finger pulling, wrist pulling, finger wrist arm pulling), lifting (finger lifting, wrist lifting, finger wrist arm lifting), clamping, pinching, picking, holding, binding, binding, twisting, tearing, peeling, pasting, etc.

Conventional educational development only pays attention to some of these functions, among which the functions of the wrist, middle finger, ring finger, little finger, especially the ring finger still have a lot of space and need to be further developed.

The hand is the main organ of human activity, and it is also an important organ for understanding things. Studies have shown that regular training of a baby's finger movements can accelerate brain development. The delicate and dexterous movements of the hands and fingers, the joints, muscles, ligaments, and tactile sensations of the hands provide rich endogenous information for the brain, which can stimulate certain creative areas in the brain, make the connection of the brain's nerve dendrites more complex and reasonable, and thus promote the development of the brain's thinking ability.

Blablah, oh road.

My hands are thin and tender,** very elastic, the fingers are slender, except for the thumb without a fight, the fingers of the other versions have the right to fight.

My hands are dexterous hands.

These hands can help me draw beautiful pictures: cute little zebras, all kinds of household appliances, dense, verdant forests, beautiful flower fairies. It's so lifelike, and my painting teacher often praises my drawings in class!

These hands can help me cut out a variety of window flowers, and I can use an ordinary piece of paper to cut out beautiful patterns such as golden rooster announcing dawn, a hundred flowers competing for beauty, and more than (fish) every year. Before the party, the teacher always asked me to cut some window grilles and stick them on the windows of the classroom to add some festive atmosphere to the party.

These hands made me write a good essay, as the saying goes: "People have two treasures, hands and brains." "Every time I write an essay, I have to think about how to write this essay with my brain, and after thinking about it, I use these hands to type out the draft, and after revision, copy it onto the composition paper sent by the teacher.

I also used these hands to beat my parents, grandparents, and grandparents who had worked hard all day, and every time I beat their backs, they would say that my little fist was very comfortable on my back, and it was tiring!

These hands have helped me do a lot of things, and I am proud to have such hands!

Categories: Sports Sports >> Racing F1

Analysis: 1. Hand bones.

The hand skeleton is made up of 27 bones. At the base of the hand, there are 8 small bones in two rows side by side, called carpal bones; In front of the carpal bones are 5 metacarpal bones; In front of the metacarpal bones are 14 phalanges, 2 thumbs, and 3 each of the other 4 fingers.

2. Hand muscles.

The hand muscles are divided into 3 groups: lateral group, medial group, and middle group, with a total of 19 pieces (bars).

The lateral group is located on the thumb side and forms a thumb side bulge called the "thenar magnaar";

The medial group is located on the side of the little finger and forms a bulge on the little finger side of the palm, called the "thenar of the minus";

The middle group is located in the center of the palm and is collectively referred to as the internal muscles of the palm. There are more than 20 muscles from the forearm and end at the metacarpal bones or phalanges, which are called the external muscles of the hand. The hands make up more muscles than any other part of the body. Because of this, the hand can do all kinds of fine movements.

3. Blood circulation in the hands.

The blood circulation of the hand is very vigorous, and the main blood vessels that make up the blood circulation are the radial artery and ulnar artery, the radial vein and the ulnar vein. When the radial artery and ulnar artery run to the palm, the superficial palmar branch and the deep palmar branch are formed respectively, and each limb is divided into many small branches, the whole finger and palm of the edge, the arterial end and the venous terminal are anastomosed, and the blood of the hand flows back to the venous system through the radial artery and ulnar artery, maintaining the normal circulation of blood in the hand. Because the capillary distribution of the hand is extremely abundant and the blood circulation is vigorous, many systemic physiological and pathological phenomena of human beings can be observed on the hand.

Fourth, the nerves of the hand.

The nerves of the hand are mainly the median nerve, ulnar nerve, and radial nerve. The median nerve is the motor nerve of the anterior muscles of the forearm and the main vegetal hall of the thenar arm, which is related to the main motor function of the hand and is also the main historical fluid sensory nerve of the palmar surface. Movement disorders after median nerve injury manifest as inability to pronate and flex the wrist of the forearm, weak abduction, inability to flex the thumb, index finger and middle finger, and inability to align the thumb.

The flat palm caused by the thenar behavior is called "ape hand" and "claw-shaped hand".

When the ulnar nerve travels through the wrist, it enters the palm of the hand lateral to the lateral aspect of the pisiform through the superficial surface of the transverse carpal ligament and the dupuytren. It is the main motor nerve of the hand muscles and the ulnar flexor muscles of the forearm, as well as the sensory nerve of the ulnar** of the hand. After ulnar nerve injury, it manifests as:

Wrist flexion is weakened, the distal parts of the ring finger and little finger cannot be flexed, the thumb cannot be retracted, and the adduction and abduction of the finger are lost; loss of sensation in the thenar little finger; Because of the atrophy and flatness of the small thenar, it is called "claw-shaped hand".

The deep branches of the radial nerve give rise to many branches, innervating the posterior forearm muscles and the back of the forearm, and the superficial branches of the radial nerve are distributed on the radial side of the dorsum of the hand and the dorsal side of the two fingers on the radial side. Radial nerve damage is manifested as: inability to stretch the wrist and fingers, thick lines "hanging the wrist"; The thumb cannot be abducted; Sensory loss in the "Hukou Zone"**.