This is my hand and I can control it as I am a normal person
Hand (from Prasslav * rǫka “hand”, from * ronka, from * ronkā, from Pra-Indo-Hebrews * wronkeh₂, from * wrenk- “to collect”) – the upper limb of a person, an organ of the musculoskeletal system , one of the most important parts of the body. With the help of hands, a person can perform many actions, the main of which is the ability to grasp objects [4] .
In Russian, the hands had their own names, now archaic : right hand (right hand) and shuytsa (left hand)
Bone skeleton and areas of the hand
The following anatomical regions and their corresponding bones are distinguished in the hand (in italics):
Shoulder girdle ( collarbone , scapula )
Shoulder ( humerus )
Forearm ( ulna , radius )
Brush
Wrist (4 in the proximal row: scaphoid, lunate, triangular, pisiform ; 4 in the distal row: trapezoid, trapezoidal, capitate, hook-shaped )
Metacarpus (5 bones)
5 fingers (14 phalanges ): thumb, index, middle, ring, little finger.
Also, each person has the so-called sesamoid bones , their position, size and number (sometimes reaching 2-3 dozen) are extremely variable.
In non-scientific literature and in society, “shoulder girdle” is called the word shoulder (this term also includes the shoulder joint with the head of the humerus).
Muscles
The muscular system of the arm consists of several layers of muscles, with many muscles thrown over more than one joint, due to which, when one muscle contracts, the positio
Innervation
The hand has efferent and afferent innervation . Efferent fibers send signals from the spinal cord to the arm, while afferent fibers send signals from the arm to the spinal cord (via the dorsal ganglia). The fibers are collected in nerves , and almost all of them are mixed, that is, they contain both efferent and afferent fibers.
Receptors of the skin, muscles and joints
The hand is equipped with a huge number of sensory endings (when the hands “go numb”, this is a sign that something is wrong with them).
How the brain controls the hand
Cortex contains areas responsible for managing individual parts of the body. These areas are often depicted as a homunculus – a little man spread out over the bark. The man’s legs are located dorsally, that is, closer to the crown of the head, and the arms and face are ventral, that is, on th
The movements of the fingers and the entire hand are possible through electrical stimulation of the brain. During surgery, this is done with electrodes applied to the surface of the brain, or inserted directly into the brain. When petting, the mother also does this by performing smooth hand movements through the child’s hair, sitting next to him until he falls asleep. The brain can also be stimulated through the skin and skull bone. For this, focal magnetic stimulation is used.
Palm ( lat. Palma manus ) , and Hand , pastern – an area of the body of primate (including human ), internal (as opposed to the rear) side brush arm from the wrist to the fingers (excluding the fingers
The bent palm forms a rook-shaped depression. This concavity (depression), limited on one side by the elevation of the thumb ( thenar ), and on the other by the elevation of the little finger ( hypothenar ), increases with adduction of the thumb and flexion of the rest. The skin of the palm is abundantly supplied with nerves and blood vessels and, as a result, has a higher temperature and sensitivity than the back of the hand, it contains a large number of sweat glands . On the skin of the palm there are three permanent lines (palmar folds), which almost never disappear with inflammation, edema, and the like.
The subcutaneous tissue of the palm is dense. The palmar aponeurosis ( aponeurosis palmaris ) in the middle of the palm is especially well developed and has the shape of a triangle, into the apex of which the tendon of the long palmar muscle is woven , and the base faces the fingers, where the aponeurosis diverges into four flat strands , between which transverse bundles are stretched. In the places of transition of the aponeurosis into thin fascial plates covering the muscles of the eminences of the thumb and little finger, partitions that connect with the fascia of the interosseous muscles extend deep into it. As a result, three fascial beds are formed on the palm – two lateral and median; lateral – for the muscles of the thumb and little finger, the middle – for the flexor tendons of the fingers [3]…themselves) [1] [2] .
The palms and palms of the fingers of primates are not covered with hair.
Prints of the papillary lines of the palm, along with fingerprints, are used in fingerprinting to identify (identify) a person.
One of the most ancient systems of divination about the individual characteristics of a person, the events he experienced and his future fate, palmistry , is based on the interpretation of the skin relief of the palms, papillary and flexor lines, as well as hills in the palm.
#hand #palm #me #mybody
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