At what time is the fetal nervous system laid down. Features of the development and maturation of the nervous system

Age changes nervous system.

The body of children in the first years of life is significantly different from the body of older people. Already in the very first days of adaptation to life outside the mother's body, the child must master the most necessary nutrition skills, adapt to various thermal environmental conditions, respond to the surrounding faces, etc. All reactions of adaptation to the conditions of the new environment require rapid development brain, especially its higher parts - the cerebral cortex.

However various zones barks do not ripen at the same time. Earlier In general, in the very first years of life, the projection zones of the cortex (primary fields) - visual, motor, auditory, etc., mature, then the secondary fields (the periphery of the analyzers) and, last of all, up to the adult state - tertiary, associative fields of the cortex (zones of higher analysis and synthesis). Thus, the motor zone of the cortex (primary field) is mainly formed by the age of 4, and the associative fields of the frontal and lower parietal cortex in terms of the territory occupied, the thickness and degree of cell differentiation by the age of 7-8 years mature only by 80%, especially lagging behind in development. in boys compared to girls.

Formed the fastest functional systems, including vertical connections between the cortex and peripheral organs and providing vital skills - sucking, defensive reactions (sneezing, blinking, etc.), elementary movements. Very early in children infancy in the region of the frontal region, a center for the identification of familiar faces is formed. However, the development of processes of cortical neurons and myelination of nerve fibers in the cortex, the processes of establishing horizontal intercentral relationships in the cerebral cortex, are slower. As a result, the first years of life are characterized by lack of interconnections in the body (for example, between the visual and motor systems, which underlies the imperfection of visual motor reactions).

Children in their first years of life need a significant amount of sleep with short breaks for wakefulness. The total duration of sleep is 16 hours at the age of 1 year, 12 hours for 4-5 years, 10 hours for 7-10 years, and 7-8 hours for adults. At the same time, the duration of the phase is especially large in children of the first years of life. REM sleep(with activation of metabolic processes, electrical activity of the brain, autonomic and motor functions and rapid eye movements) compared with the phase " slow-motion sleep(when all these processes slow down). The severity of REM sleep is associated with the ability of the brain to learn, which corresponds to the active knowledge of the outside world in childhood.

Electrical activity of the brain (EEG) reflects the disunity of various areas of the cortex and the immaturity of cortical neurons - it is irregular, does not have dominant rhythms and pronounced foci of activity, slow waves predominate. In children under the age of 1 year, there are mainly waves with a frequency of 2-4 oscillations per 1 second. Then the predominant frequency of oscillations of electrical potentials increases: at 2-3 years - 4-5 oscillations / s; at 4-5 years old - 6 fluctuations / s; at 6-7 years old - 6 and 10 fluctuations / s; at 7-8 years old - 8 fluctuations / s; at 9 years old - 9 fluctuations / s; the interconnectedness of the activity of various cortical zones increases (Khrizman T. P., 1978). By the age of 10 years, the basic rhythm of rest is established -10 oscillations / s (alpha rhythm), characteristic of an adult organism.

For the nervous system children of preschool and primary school age characterized by high excitability and weakness of inhibitory processes, which leads to a wide irradiation of excitation along the cortex and insufficient coordination of movements. However, long-term maintenance of the excitation process is still impossible, and children quickly get tired. When organizing classes with younger students, and especially with preschoolers, long instructions and instructions, lengthy and monotonous tasks should be avoided. It is especially important to strictly dose the loads, since children of this age are different. underdeveloped sense of fatigue. They poorly assess changes in the internal environment of the body during fatigue and cannot fully reflect them in words even when completely exhausted.

With the weakness of cortical processes in children, subcortical processes of excitation predominate. Children at this age are easily distracted by any external stimulus. In such an extreme severity of the orienting reaction (according to I.P. Pavlov, the reflex “What is it?”) Is reflected involuntary nature of their attention. Arbitrary attention is very short-term: children 5-7 years old are able to focus only for 15-20 minutes.

In a child of the first years of life subjective sense of time is poorly developed. Most often, he cannot correctly measure and reproduce the given intervals, keep within time when performing various tasks. Insufficient synchronization of internal processes in the body and little experience in comparing one's own activity with external synchronizers (estimation of the duration of the flow) various situations, change of day and night, etc.). With age, the sense of time improves: for example, only 22% of 6-year-olds, 39% of 8-year-olds and 49% of 10-year-olds accurately reproduce the interval of 30 seconds.

Body scheme is formed in a child by the age of 6, and more complexspatial representations - by 9-10 years, which depends on the development of the cerebral hemispheres and the improvement of sensorimotor functions.

Insufficient development of the frontal programming zones of the cortex causes weak development of extrapolation processes. The ability to foresee the situation at 3-4 years old is practically absent in a child (it appears at 5-6 years old). It is difficult for him to stop running at a given line, to substitute his hands in time to catch the ball, etc.

Higher nervous activity children of preschool and primary school age is characterized by a slow generation th piecework conditioned reflexes and the formation of dynamic stereotypes, as well as the particular difficulty of their alteration. Great importance for the formation of motor skills has the use of imitative reflexes, the emotionality of classes, gaming activities.

Children 2-3 are distinguished by a strong stereotypical attachment to an unchanged environment, to familiar faces around them and to acquired skills. Alteration of these stereotypes occurs with great difficulty, often leading to disruptions in higher nervous activity. In 5-6-year-old children, the strength and mobility of nervous processes increase. They are able to consciously build programs of movements and control their implementation, it is easier to rebuild programs.

In junior school age the predominant influences of the cortex on subcortical processes are already emerging, the processes of internal inhibition and voluntary attention are intensified, the ability to master complex programs of activity appears, characteristic individual-typological features of higher nervous activity child.

Of particular importance in the behavior of the child is speech development. Until the age of 6, reactions to direct signals predominate in children (the first signal system, according to I.P. Pavlov), and from the age of 6, speech signals begin to dominate (the second signal system).

In middle and senior school age, significant development is noted in all higher structures of differentiation of the central nervous system. By the period of puberty, the weight of the brain in comparison with the newborn increases by 3.5 times and by 3 times in girls.

Up to 13-15 years, the development of the diencephalon continues. There is an increase in the volume and nerve fibers of the thalamus, the nuclei of the hypothalamus. By the age of 15, the cerebellum reaches adult size.

In the cerebral cortex total length furrows by the age of 10 increases by 2 times, and the area of ​​the cortex - by 3 times. In adolescents, the process of myelination of the nerve pathways ends.

The period from 9 to 12 years is characterized by a sharp increase in the relationship between various cortical centers, mainly due to the growth of neuronal processes in the horizontal direction. This creates a morphological and functional basis for the development of the integrative functions of the brain, the establishment of intersystem relationships.

At the age of 10-12 years, the inhibitory effects of the cortex on the subcortical structures increase. Cortical-subcortical relationships close to the adult type are formed with the leading role of the cerebral cortex and the subordinate role of the subcortex.

In the EEG, by the age of 10-12, an adult type of electrical activity is established. with stabilization of the amplitude and frequency of cortical potentials, a pronounced dominance of the alpha rhythm (8-12 vibrations / s) and a characteristic distribution of rhythmic activity over the surface of the cortex.

At various types activity with an increase in age from 10 to 13 years, the EEG recorded a sharp increase in the spatial synchronization of the potentials of different cortical zones, which reflects the establishment of functional relationships between them. A functional basis is created for systemic processes in the cortex, providing a high level of extraction useful information from afferent messages, building complex multipurpose behavioral programs. In 13-year-old adolescents, the ability to process information, make quick decisions, and increase the efficiency of tactical thinking are significantly improved. The time for solving tactical tasks is significantly reduced in comparison with 10-year ones. It changes little by the age of 16, but does not yet reach adult values.

The noise immunity of behavioral reactions and motor skills reaches an adult level by the age of 13 years. This ability has great individual differences, it is genetically controlled and changes little during training.

The smooth improvement of brain processes in adolescents is disturbed as they enter puberty - in girls at 11-13 years old, in boys at 13-15 years old. This period is characterized weakening of the inhibitory influences of the cortex on the underlying structures and the "violence" of the subcortex, causing strong arousal for throughout the cortex and increased emotional reactions in adolescents. Increasing activity sympathetic department nervous system and the concentration of adrenaline in the blood. The blood supply to the brain is deteriorating.

Such changes lead to a violation of the fine mosaic of excited and inhibited areas of the cortex, disrupt the coordination of movements, impair memory and sense of time. Adolescents' behavior becomes unstable, often unmotivated and aggressive. Significant changes also occur in interhemispheric relations - the role of the right hemisphere in behavioral responses is temporarily enhanced. In a teenager, the activity of the second signaling system (speech functions) worsens, the importance of visual-spatial information increases. Violations of higher nervous activity are noted - all types of internal inhibition are violated, the formation of conditioned reflexes, the consolidation and alteration of dynamic stereotypes are hindered. There are sleep disorders.

A decrease in the controlling influences of the cortex on behavioral reactions leads to the suggestibility and lack of independence of a number of adolescents who easily adopt bad habits, trying to imitate older comrades. It is at this age that most often there is a craving for smoking, alcoholism, and taking drugs. The contingent of those infected with the human immunodeficiency virus (HIV) and suffering from this AIDS (acquired immunodeficiency syndrome) is especially growing. The systematic use of hard drugs leads to death within 4 years after the start of the intake. The highest frequency of deaths is recorded in drug addicts around the age of 21. The life of AIDS patients goes on a little longer. An increase in the number of people with AIDS last years requires increased attention to prevent and control this condition. One of the most important means of prevention bad habits are exercise and sports.

Hormonal and structural changes in the transitional period slow down the growth of the body in length, reduce the rate of development of strength and endurance.

With the end of this period of restructuring in the body (after 13 years in girls and 15 years in boys), the leading role of the left hemisphere of the brain again increases, cortical-subcortical relations are being established with the leading role of the cortex. The increased level of cortical excitability decreases and the processes of higher nervous activity are normalized.

The transition from the age of adolescents to adolescence is marked by an increased role of the anterior frontal tertiary fields and transition of the dominant role from the right to the left hemisphere (in right-handers). This leads to a significant improvement in abstract-logical thinking, the development of a second signal system and extrapolation processes. The activity of the central nervous system is very close to the adult level.

• 1) Dorsal induction or Primary neurulation - a period of 3-4 weeks of gestation;
• 2) Ventral induction - the period of 5-6 weeks of gestation;
• 3) Neuronal proliferation - a period of 2-4 months of gestation;
• 4) Migration - a period of 3-5 months of gestation;
• 5) Organization - a period of 6-9 months of fetal development;
• 6) Myelination - takes the period from the moment of birth and in the subsequent period of postnatal adaptation.

IN first trimester of pregnancy the following stages of development of the nervous system of the fetus occur:

Dorsal induction or Primary neurulation - due to individual characteristics development may vary in time, but always adheres to 3-4 weeks (18-27 days after conception) of gestation. During this period, the formation of the neural plate occurs, which, after closing its edges, turns into a neural tube (4-7 weeks of gestation).

Ventral induction - this stage of the formation of the fetal nervous system reaches its peak at 5-6 weeks of gestation. During this period, 3 expanded cavities appear at the neural tube (at its anterior end), from which are then formed:

from the 1st (cranial cavity) - the brain;

from the 2nd and 3rd cavity - the spinal cord.

Due to the division into three bubbles, the nervous system develops further and the rudiment of the fetal brain from three bubbles turns into five by division.

From forebrain formed - telencephalon and diencephalon.

From the posterior cerebral bladder - the laying of the cerebellum and medulla oblongata.

Partial neuronal proliferation also occurs in the first trimester of pregnancy.

The spinal cord develops faster than the brain, and, therefore, it also begins to function faster, which is why it plays more important role during the early stages of fetal development.

But in the first trimester of pregnancy Special attention deserves the development of the vestibular analyzer. It is a highly specialized analyzer that is responsible in the fetus for the perception of movement in space and the sensation of a change in position. This analyzer is formed already at the 7th week of intrauterine development (earlier than other analyzers!), and by the 12th week nerve fibers are already approaching it. Myelination of nerve fibers begins by the time the first movements appear in the fetus - at 14 weeks of gestation. But in order to conduct impulses from the vestibular nuclei to the motor cells of the anterior horns of the spinal cord, the vestibulo-spinal tract must be myelinated. Its myelination occurs after 1-2 weeks (15 - 16 weeks of gestation).

Therefore, due to the early formation vestibular reflex, when a pregnant woman moves in space, the fetus moves into the uterine cavity. At the same time, the movement of the fetus in space is an “irritating” factor for the vestibular receptor, which sends impulses for the further development of the fetal nervous system.

Violations of the development of the fetus from the influence of various factors during this period leads to violations vestibular apparatus in a newborn baby.

Until the 2nd month of gestation, the fetus has a smooth surface of the brain covered with an ependymal layer consisting of medulloblasts. By the 2nd month of intrauterine development, the cerebral cortex begins to form by migration of neuroblasts to the overlying marginal layer, and thus forming the anlage of the gray matter of the brain.

All adverse factors in the first trimester of the development of the fetal nervous system lead to severe and, in most cases, irreversible impairments in the functioning and further formation of the fetal nervous system.

Second trimester of pregnancy.

If in the first trimester of pregnancy the main laying of the nervous system occurs, then in the second trimester its intensive development occurs.

Neuronal proliferation is the main process of ontogeny.

At this stage of development, physiological dropsy of the cerebral vesicles occurs. This is due to the fact that the cerebrospinal fluid, entering the brain bubbles, expands them.

By the end of the 5th month of gestation, all the main sulci of the brain are formed, and Luschka's foramina also appear, through which the cerebrospinal fluid enters the outer surface of the brain and washes it.

During 4-5 months of brain development, the cerebellum develops intensively. It acquires its characteristic sinuosity, and divides across, forming its main parts: anterior, posterior and follicle-nodular lobes.

Also in the second trimester of pregnancy, the stage of cell migration takes place (month 5), as a result of which zonality appears. The fetal brain becomes more similar to the brain of an adult child.

Under the influence of unfavorable factors on the fetus during the second period of pregnancy, there are violations that are compatible with life, since the laying of the nervous system took place in the first trimester. At this stage, disorders are associated with underdevelopment of brain structures.

Third trimester of pregnancy.

During this period, the organization and myelination of brain structures occurs. Furrows and convolutions in their development are approaching the final stage (7-8 months of gestation).

Under the organization stage nervous structures understand morphological differentiation and the emergence of specific neurons. In connection with the development of the cytoplasm of cells and an increase in intracellular organelles, there is an increase in the formation of metabolic products that are necessary for the development of nervous structures: proteins, enzymes, glycolipids, mediators, etc. In parallel with these processes, the formation of axons and dendrites occurs to ensure synoptic contacts between neurons.

Myelination of nerve structures begins from 4-5 months of gestation and ends by the end of the first, beginning of the second year of a child's life, when the child begins to walk.

When exposed to adverse factors in the third trimester of pregnancy, as well as during the first year of life, when the myelination processes end pyramidal pathways, there are no serious violations. There may be slight changes in the structure, which are determined only by histological examination.

The development of cerebrospinal fluid and the circulatory system of the brain and spinal cord.

In the first trimester of pregnancy (1 - 2 months of gestation), when the formation of five cerebral vesicles occurs, the formation of vascular plexuses occurs in the cavity of the first, second and fifth cerebral vesicles. These plexuses begin to secrete highly concentrated cerebrospinal fluid, which is, in fact, a nutrient medium due to the high content of protein and glycogen in its composition (exceeds 20 times, unlike adults). Liquor - in this period is the main source of nutrients for the development of the structures of the nervous system.

While the development of brain structures supports the cerebrospinal fluid, at 3-4 weeks of gestation, the first vessels of the circulatory system are formed, which are located in the soft arachnoid membrane. Initially, the oxygen content in the arteries is very low, but during the 1st to 2nd month of intrauterine development, the circulatory system becomes more mature. And in the second month of gestation, blood vessels begin to grow into the medulla, forming a circulatory network.

By the 5th month of development of the nervous system, anterior, middle and posterior cerebral arteries, which are interconnected by anastomoses, and represent a complete structure of the brain.

The blood supply to the spinal cord comes from more sources than to the brain. Blood to the spinal cord comes from two vertebral arteries, which branch into three arterial tracts, which, in turn, run along the entire spinal cord, feeding it. The anterior horns receive large quantity nutrients.

The venous system eliminates the formation of collaterals and is more isolated, which contributes to the rapid removal of the end products of metabolism through the central veins to the surface of the spinal cord and into the venous plexus of the spine.

A feature of the blood supply to the third, fourth and lateral ventricles in the fetus is the wider size of the capillaries that pass through these structures. This leads to slower blood flow, which leads to more intense nutrition.

The birth and intrauterine development of a new person is a complex but well-coordinated process. The formation of the fetus by weeks shows that an unborn baby is passing inside the woman.

For an embryo, every day is new stage development. A photo of the fetus by weeks of pregnancy proves that every day the fetus becomes more and more like a person and goes through a difficult path for this.

First - fourth weeks of fetal life

After the fusion of the egg with the sperm in seven days, a new organism is implanted in the uterine cavity. The formation of the fetus from the moment of conception begins with the connection of the villi of the embryo with blood vessels. This is the beginning of the formation of the umbilical cord and membranes.

From the second week, the foundation of the neural tube begins to form in the fetus - this is the structure that is the main link in the central nervous system. The embryo is fully attached to the walls of the uterus for further development and nutrition.

The formation of the heart in the fetus occurs in the third week and already on the 21st day it begins to beat. The cardiovascular system of the embryo is formed first and serves as the basis for the full-fledged emergence of new organs.

The fourth week is marked by the start of blood circulation in the body of the fetus. Organs such as the liver, intestines, lungs, and spine begin to form.

Embryo growth in the second obstetric month

During the fifth week are formed:

• eyes, inner ear;
• nervous system;
• the circulatory system develops;
• pancreas;
• digestive system;
• nasal cavity;
• upper lip;
• limb rudiments

In the same period, the formation of sex in the fetus occurs. Although it will be possible to determine whether a boy or a girl will be born much later.

During the sixth week, the development of the cerebral cortex continues, facial muscles begin to appear. The basis of the fingers and nails is formed. The heart is divided into two chambers, followed by the ventricles and atria. The liver and pancreas are practically formed. pregnancy changes slightly at first, active growth embryo starts from the fourth month.

The seventh week is significant in that the umbilical cord has completed its formation completely, now nutrients are supplied to the fetus with its help. The embryo can already open its mouth, eyes and fingers have appeared.

This month, the following changes occur with the fetus:

• a nasal fold appears;
• ears, nose begin to develop;
• the webbing between the fingers disappears

Fetal life from 9 to 12 weeks

Since the embryo receives nutrients from the woman's blood, the development of the fetus by weeks of pregnancy largely depends on what it eats. future mother. Make sure you get enough protein in your body.

During the ninth week, the joints of the fingers and hands are formed in the fetus. develops, which in the future will provide the basis for the appearance of the adrenal glands.

10-11 weeks of embryonic life are characterized by the following stages:

• a sucking reflex is developed;
• the fetus can already turn its head;
• buttocks are formed;
• it becomes possible to move your fingers;
• eyes continue to form

The twelfth week is characterized by the development of the genital organs, the fetus is trying to make respiratory movements. Nervous and digestive system continue their development.

What happens to the embryo in the fourth month of pregnancy

The formation of the fetus by weeks during the fourth month is as follows:

• eyes, ears, nose, mouth are already clearly visible on the face;
• in the circulatory system, the blood group, Rh factor is determined;
• urination begins in the amniotic fluid;
• completely appeared fingers on the legs, hands;
• nail plates have formed;
• insulin begins to be produced;
• in girls, the formation of ovaries, in boys - prostate, but it is still difficult to determine the sex of the child on ultrasound

The child develops swallowing and sucking reflexes. He can already clench his fists, make movements with his hands. The baby sucks his thumb and can swim in it. This is his first habitat. It protects the child from damage, takes part in the metabolism, and gives a certain freedom of movement.

By the end of the fourth month, the baby's eyes open, and the retina continues to form.

17 - 20 weeks of fetal growth

During the seventeenth week, the baby begins to hear sounds. The heartbeat intensifies, the expectant mother can already hear it.

The development of the fetus by weeks of pregnancy is an energy-intensive activity, therefore, during the eighteenth week, the child sleeps almost all the time and occupies an upright position. During his wakefulness, the woman begins to feel tremors.

At 19-20 weeks, the fetus sucks a finger, learns to smile, frown, close his eyes. Formed adrenal glands, pituitary gland, pancreas.

During this period, the baby's head has a disproportionate size, this is due to the dominant formation of the brain. The child's immunity is strengthened by the synthesis of immunoglobulin and interferon.

sixth month of pregnancy

The formation of the fetus by week of the sixth month is marked by an increase in the time when the child is awake. He begins to take an interest in his body. This consists in touching the face, tilting the head.

The fetal brain continues to develop, neurons work at full capacity. The heart muscle increases in size, the vessels improve. During this period, the baby learns to breathe, the number of inhalations and exhalations increases. The lungs have not yet completed their development, but alveoli are already forming on them.

The sixth month is significant in that at this time an emotional connection is established between the child and the mother. All the feelings experienced by a woman are transmitted to the baby. If a pregnant woman is afraid, then the fetus will also begin to behave anxiously. Therefore, it is recommended that the expectant mother avoid negative emotions.

At the twenty-fourth week, the child's eyes and hearing are fully formed. He can already respond to various sounds.

Fetal development from 25 to 28 weeks

The development of the fetus by weeks of pregnancy from 25 to 28 is characterized by the following changes:

• the formation of lung tissue occurs, the lungs begin to produce a surfactant - a substance that is aimed at reducing excessive stress in these organs;
• the child has a metabolism;
• hemispheres of the brain begin to function;
• the genitals continue to develop;
• bones become stronger, the child can already smell;
• baby's eyelids open
• a fatty layer is formed;
• body covered with fluffy hairs

At a period of seven and a half months, the fetus can already be born, while the chance of survival is very high. But in case of premature birth, the mother's body has not yet developed the necessary amount of antibodies for the baby, so the resistance to diseases in such a child will be low.

The eighth month of a baby's life in the womb

The formation of the fetus by weeks of the eighth month is determined by the development of almost all organs. The cardiovascular system improves blood circulation, the endocrine system produces almost all hormones. In the body of the child, self-regulation of sleep and wakefulness occurs.

Due to the fact that the baby's body produces a hormone that favors increased output estrogen in the expectant mother, her mammary glands prepare for the formation and production of milk.

The fluff that has formed on the body of the child gradually disappears during this period, instead a special lubricant is formed. The cheeks, arms, legs, hips, shoulders of a small person acquire roundness due to the accumulation of the necessary fat layer.

It is scientifically proven that the baby can already dream. Since it increases and it occupies almost the entire space in the uterus, its activity decreases.

Fetus at 33 - 36 weeks of gestation

The formation of the fetus during this period comes to the final stage before childbirth. His brain is active internal organs work almost like an adult, the nails are formed.

During the 34th week, the baby's hair grows, right now his body needs calcium so much for proper development and strengthening bones. In addition, the child's heart increases, vascular tone improves.

At 36 weeks small man occupies a position in which his head, arms, legs are pressed against the body. By the end of this period, the child is fully mature for existence outside the mother's womb.

Tenth obstetric month

Gynecologists and ordinary people have different opinions about how long a child is born. It is customary in society to talk about nine months, but doctors have their own calculation, the baby is born after ten obstetric months. One medical week is considered 7 days. Accordingly, there are only 28 days in the obstetric month. This is how the “extra” month runs.

A photo of the fetus by weeks of pregnancy shows that the baby is ready for birth at the end of the term. His stomach contracts, thus proving the possibility of eating not through the umbilical cord. The baby can smell, hear sounds, taste.

The brain is formed, the necessary amount of hormones is produced in the body, the metabolism is established in the cycle necessary for the fetus.

About fourteen days before delivery, the baby descends. From that moment on, birth can come at any moment.

How does the weight of the fetus change by week of pregnancy

Checking fetal weight throughout pregnancy is very important. Any deviation from the norm can indicate violations in the development of the child.

Weight is influenced not only by the nutrients supplied to the baby, but also by genetic predisposition. If parents know how much they weighed at birth, then we can assume the size of the child.

The table below shows by week.

Table of growth and weight of the fetus

A week	Weight, g	Height, cm

The formation of the fetus by weeks of pregnancy shows that at times close to childbirth, weight gain slows down, the growth of the child practically does not change.

For the baby to receive enough nutrients and developed normally, the expectant mother should pay attention to proper healthy nutrition. Try to exclude flour products, as exceeding the norm of weight gain can lead to health problems for the child.

Understanding how a fetus develops in the womb will help you avoid unnecessary fears and unnecessary fears.

CHAPTER 10. DEVELOPMENT OF THE NERVOUS SYSTEM IN NEWBORN AND CHILDREN OF EARLY AGE. RESEARCH METHOD. SYNDROMES OF DEFEAT

CHAPTER 10. DEVELOPMENT OF THE NERVOUS SYSTEM IN NEWBORN AND CHILDREN OF EARLY AGE. RESEARCH METHOD. SYNDROMES OF DEFEAT

In a newborn baby reflex acts are carried out at the level of the stem and subcortical parts of the brain. By the time of the birth of the child, the limbic system, the precentral region, especially field 4, which provides early phases motor reactions, occipital lobe and field 17. The temporal lobe is less mature (especially the temporo-parietal-occipital region), as well as the lower parietal and frontal regions. However, field 41 of the temporal lobe (projection field auditory analyzer) by the time of birth is more differentiated than field 22 (projective-associative).

10.1. Development motor functions

Motor development in the first year of life is a clinical reflection of the most complex and currently insufficiently studied processes. These include:

The action of genetic factors - the composition of expressed genes that regulate the development, maturation and functioning of the nervous system, changing in spatio-temporal dependence; neurochemical composition of the CNS, including the formation and maturation of mediator systems (the first mediators are found in the spinal cord from 10 weeks of gestation);

myelination process;

Macro- and microstructural formation of the motor analyzer (including muscles) in early ontogenesis.

First spontaneous movements embryos appear on the 5-6th week of intrauterine development. During this period, motor activity is carried out without the participation of the cerebral cortex; segmentation of the spinal cord and differentiation of the musculoskeletal system occur. The formation of muscle tissue begins from the 4-6th week, when active proliferation occurs at the sites of muscle formation with the appearance of primary muscle fibers. The emerging muscle fiber is already capable of spontaneous rhythmic activity. Simultaneously, the formation of neuromuscular

synapses under the influence of neuron induction (i.e., the axons of the emerging motor neurons of the spinal cord grow into the muscles). In addition, each axon branches many times, forming synaptic contacts with dozens of muscle fibers. Activation of muscle receptors affects the establishment of intracerebral connections of the embryo, which provides tonic excitation of brain structures.

In the human fetus, reflexes develop from local to generalized and then to specialized reflex acts. The first reflex movements appear at 7.5 weeks of gestation - trigeminal reflexes that occur with tactile irritation of the face area; at 8.5 weeks, lateral flexion of the neck is noted for the first time. On the 10th week, a reflex movement of the lips is observed (a sucking reflex is formed). Later, as the reflexogenic zones in the lips and oral mucosa mature, complex components are added in the form of opening and closing the mouth, swallowing, stretching and squeezing the lips (22 weeks), sucking movements (24 weeks).

tendon reflexes appear on the 18-23rd week of intrauterine life, at the same age, a grasping reaction is formed, by the 25th week all without conditioned reflexes called from the upper limbs. From the 10.5-11th week, reflexes from the lower extremities, primarily plantar, and a reaction of the Babinski reflex type (12.5 weeks). First irregular respiratory movements of the chest (according to the Cheyne-Stokes type), arising on the 18.5-23rd week, pass into spontaneous breathing by the 25th week.

In postnatal life, the improvement of the motor analyzer occurs at the micro level. After birth, the thickening of the cerebral cortex in areas 6, 6a and the formation of neuronal groups continue. The first networks formed from 3-4 neurons appear at 3-4 months; after 4 years, the thickness of the cortex and the size of neurons (except for Betz cells growing until puberty) stabilize. The number of fibers and their thickness increase significantly. The differentiation of muscle fibers is associated with the development of motor neurons of the spinal cord. Only after the appearance of heterogeneity in the population of motor neurons of the anterior horns of the spinal cord does the division of muscles into motor units occur. Later, at the age of 1 to 2 years, not individual muscle fibers develop, but “superstructures” - motor units consisting of muscles and nerve fibers, and changes in the muscles are primarily associated with the development of the corresponding motor neurons.

After the birth of a child, as the controlling parts of the CNS mature, so do its pathways, in particular, myelination of peripheral nerves occurs. At the age of 1 to 3 months, the development of the frontal and temporal areas of the brain is especially intensive. The cerebellar cortex is still poorly developed, but the subcortical ganglia are clearly differentiated. Up to the midbrain region, myelination of fibers is well expressed; in the cerebral hemispheres, only sensory fibers are fully myelinated. From 6 to 9 months, long associative fibers are most intensively myelinated, the spinal cord is completely myelinated. By the age of 1 year, myelination processes covered long and short associative pathways of the temporal and frontal lobes and the spinal cord along its entire length.

There are two periods of intense myelination: the first of them lasts from 9-10 months of intrauterine life to 3 months of postnatal life, then from 3 to 8 months the rate of myelination slows down, and from 8 months the second period of active myelination begins, which lasts until the child learns to walk (t .e. on average up to 1 g 2 months). With age, both the number of myelinated fibers and their content in individual peripheral nerve bundles change. These processes, which are most intense in the first 2 years of life, are mostly completed by the age of 5.

An increase in the speed of impulse conduction along the nerves precedes the emergence of new motor skills. So, in the ulnar nerve, the peak of the increase in the speed of impulse conduction (SPI) falls on the 2nd month of life, when the child can a short time clasp hands while lying on the back, and for the 3-4th month, when hypertonicity in the hands is replaced by hypotension, the volume of active movements increases (holds objects in the hand, brings them to the mouth, clings to clothes, plays with toys). In the tibial nerve, the greatest increase in SPI appears first at 3 months and precedes the disappearance of physiological hypertension in lower limbs, which coincides with the disappearance automatic gait and positive support reaction. For the ulnar nerve, the next rise in SPI is noted at 7 months with the onset of a jump preparation reaction and the extinction of the grasping reflex; in addition, there is an opposition of the thumb, an active force appears in the hands: the child shakes the bed and breaks toys. For the femoral nerve, the next increase in the conduction velocity corresponds to 10 months, for the ulnar nerve - 12 months.

At this age, free standing and walking appear, hands are freed: the child waves them, throws toys, claps his hands. Thus, there is a correlation between the increase in SPI in the fibers of the peripheral nerve and the development of the child's motor skills.

10.1.1. Reflexes of newborns

Reflexes of newborns - this is an involuntary muscular reaction to a sensitive stimulus, they are also called: primitive, unconditioned, innate reflexes.

Unconditioned reflexes according to the level at which they close can be:

1) segmental stem (Babkina, sucking, proboscis, search);

2) segmental spinal (grasping, crawling, support and automatic gait, Galant, Perez, Moro, etc.);

3) postural suprasegmental - levels of the brainstem and spinal cord (asymmetric and symmetrical tonic neck reflexes, labyrinth tonic reflex);

4) posotonic suprasegmental - the level of the midbrain (straightening reflexes from the head to the neck, from the trunk to the head, from the head to the trunk, start reflex, balance reaction).

The presence and severity of the reflex is an important indicator of psychomotor development. Many neonatal reflexes disappear as the child develops, but some of them can be found in adulthood, but they do not have topical significance.

The absence of reflexes or pathological reflexes in a child, a delay in the reduction of reflexes characteristic of an earlier age, or their appearance in an older child or adult indicate CNS damage.

Unconditioned reflexes are examined in the position on the back, stomach, vertically; it can reveal:

The presence or absence, inhibition or strengthening of the reflex;

The time of appearance from the moment of irritation (latent period of the reflex);

The severity of the reflex;

The speed of its extinction.

Unconditioned reflexes are influenced by factors such as the type of higher nervous activity, the time of day, and the general condition of the child.

The most constant unconditioned reflexes In the supine position:

search reflex- the child lies on his back, when stroking the corner of the mouth it lowers, and the head turns in the direction of irritation; options: opening the mouth, lowering the lower jaw; the reflex is especially well expressed before feeding;

defensive reaction- pain stimulation of the same area causes the head to turn in the opposite direction;

proboscis reflex- the child lies on his back, a light quick blow to the lips causes a contraction of the circular muscle of the mouth, while the lips are pulled out with a "proboscis";

sucking reflex- active sucking of the nipple inserted into the mouth;

palmar-mouth reflex (Babkina)- pressure on the thenar area of ​​the palm causes the opening of the mouth, tilt of the head, flexion of the shoulders and forearms;

grasping reflex occurs when a finger is inserted into the child's open palm, while his hand covers the finger. An attempt to release the finger leads to an increase in grasping and suspension. In newborns, the grasp reflex is so strong that they can be lifted off the changing table if both hands are involved. The lower grasp reflex (Wercombe) can be induced by pressing on the pads under the toes at the base of the foot;

Robinson reflex- when you try to release the finger, suspension occurs; this is a logical continuation of the grasping reflex;

lower grasp reflex- plantar flexion of the fingers in response to touching the base of II-III toes;

Babinski reflex- with stroke stimulation of the sole of the foot, a fan-shaped divergence and extension of the fingers occur;

Moro reflex: I phase - breeding of hands, sometimes so pronounced that it occurs with a turn around the axis; Phase II - return to the starting position after a few seconds. This reflex is observed when the child is suddenly shaken, loud sound; the spontaneous Moro reflex often causes a baby to fall off the changing table;

defensive reflex- when the sole is injected, the leg is triple flexed;

cross reflex extensors- a prick of the sole, fixed in the extended position of the leg, causes straightening and slight adduction of the other leg;

start reflex(extension of arms and legs in response to a loud sound).

Upright (normally, when the child is vertically suspended by the armpits, bending occurs in all joints of the legs):

support reflex- in the presence of a solid support under the feet, the body straightens and rests on a full foot;

automatic gait occurs if the child is slightly tilted forward;

rotational reflex- when rotating in vertical suspension by the armpits, the head turns in the direction of rotation; if at the same time the head is fixed by the doctor, then only the eyes turn; after the appearance of fixation (by the end of the neonatal period), the turn of the eyes is accompanied by nystagmus - assessment of the vestibular response.

In the prone position:

defensive reflex- when laying the child on the stomach, the head turns to the side;

crawl reflex (Bauer)- light pushing of the hand to the feet causes repulsion from it and movements resembling crawling;

Talent reflex- when the skin of the back near the spine is irritated, the body bends in an arc open towards the stimulus; the head turns in the same direction;

Perez reflex- when you run your finger along the spinous processes of the spine from the coccyx to the neck, a pain reaction, a cry occur.

Reflexes that persist in adults:

Corneal reflex (squinting the eye in response to touch or sudden exposure to bright light);

Sneezing reflex (sneezing when the nasal mucosa is irritated);

Gag reflex (vomiting when irritated) rear wall pharynx or root of the tongue);

Yawning reflex (yawning with a lack of oxygen);

Cough reflex.

Assessment of the motor development of the child of any age is carried out at the moment of maximum comfort (warmth, satiety, peace). It should be borne in mind that the development of the child occurs craniocaudally. This means that the upper parts of the body develop before the lower ones (for example,

manipulation precedes the ability to sit, which, in turn, precedes the appearance of walking). In the same direction, muscle tone also decreases - from physiological hypertonicity to hypotension by 5 months of age.

The components of the assessment of motor functions are:

muscle tone and postural reflexes(proprioceptive reflexes of the muscular-articular apparatus). There is a close relationship between muscle tone and postural reflexes: muscle tone affects posture in sleep and in a state of calm wakefulness, and posture, in turn, affects tone. Tone options: normal, high, low, dystonic;

tendon reflexes. Options: absence or decrease, increase, asymmetry, clonus;

volume of passive and active movements;

unconditioned reflexes;

pathological movements: tremor, hyperkinesis, convulsions.

At the same time, attention should be paid to the general condition of the child (somatic and social), the characteristics of his emotional background, the function of analyzers (especially visual and auditory) and the ability to communicate.

10.1.2. Development of motor skills in the first year of life

Newborn. Muscle tone. Normally, the tone in the flexors predominates (flexor hypertension), and the tone in the arms is higher than in the legs. As a result of this, a “fetal position” arises: the arms are bent at all joints, brought to the body, pressed to chest, hands clenched into fists, thumbs squeezed by the rest; the legs are bent in all joints, slightly abducted at the hips, in the feet - dorsiflexion, the spine is curved. Muscle tone is increased symmetrically. To determine the degree of flexor hypertension, there are the following tests:

traction test- the child lies on his back, the researcher takes him by the wrists and pulls him towards himself, trying to seat him. At the same time, the arms are slightly unbent in the elbow joints, then the extension stops, and the child is pulled up to the hands. With an excessive increase in flexor tone, there is no extension phase, and the body immediately moves behind the hands, with insufficiency, the extension volume increases or there is no sipping behind the hands;

With normal muscle tone in a horizontal hanging posture behind the armpits, face down, the head is in line with the body. In this case, the arms are bent, and the legs are extended. With a decrease in muscle tone, the head and legs passively hang down, with an increase, a pronounced bending of the arms and, to a lesser extent, legs occurs. With the predominance of extensor tone, the head is thrown back;

labyrinthine tonic reflex (LTR) occurs when the position of the head in space changes as a result of stimulation of the labyrinths. This increases the tone in the extensors in the supine position and in the flexors in the prone position;

symmetrical neck tonic reflex (SNTR)- in the position on the back with a passive tilt of the head, the tone of the flexors in the arms and extensors in the legs increases, with the extension of the head - the opposite reaction;

asymmetric neck tonic reflex (ASTTR), Magnus-Klein reflex occurs when the head of a child lying on his back is turned to the side. At the same time, in the hand, to which the child's face is turned, the extensor tone increases, as a result of which it unbends and is retracted from the body, the hand opens. At the same time, the opposite arm is bent and her hand is clenched into a fist (swordsman's pose). As the head turns, the position changes accordingly.

Volume of passive and active movements

Flexor hypertension overcome, but limits the amount of passive movement in the joints. You can not completely unbend the child's arms in elbow joints, raise your arms above the horizontal level, spread your hips without causing pain.

Spontaneous (active) movements: periodic flexion and extension of the legs, cross, repulsion from the support in the position on the stomach and back. Movements in the hands are made in the elbow and wrist joints (hands clenched into fists move at chest level). Movements are accompanied by an athetoid component (a consequence of the immaturity of the striatum).

Tendon reflexes: the newborn can only cause knee jerks, which are usually elevated.

Unconditioned reflexes: all reflexes of newborns are caused, they are moderately expressed, slowly are exhausted.

Postural reactions: the newborn lies on his stomach, his head is turned to the side (protective reflex), the limbs are bent in

all joints and brought to the body (labyrinth tonic reflex). Direction of development: exercises for holding the head vertically, leaning on the hands.

Walking Ability: a newborn and a child of 1–2 months of age have a primitive reaction of support and automatic gait, which fades by 2–4 months of age.

Grasping and manipulation: in a newborn and a child of 1 month, the hands are clenched into a fist, he cannot open the hand on his own, a grasping reflex is caused.

Social contacts: The first impressions of the newborn about the world around are based on skin sensations: warm, cold, soft, hard. The child calms down when he is picked up, fed.

Child aged 1-3 months. When evaluating the motor function, in addition to those listed earlier (muscle tone, postural reflexes, the volume of spontaneous movements, tendon reflexes, unconditioned reflexes), the initial elements of voluntary movements and coordination begin to be taken into account.

Skills:

Development of analyzer functions: fixation, tracking (visual), sound localization in space (auditory);

Integration of analyzers: sucking fingers (sucking reflex + influence of the kinesthetic analyzer), examining one's own hand (visual-kinesthetic analyzer);

The appearance of more expressive facial expressions, a smile, a complex of revival.

Muscle tone. Flexor hypertension gradually decreases. At the same time, the influence of postural reflexes increases - ASTR, LTE are more pronounced. The value of postural reflexes is to create a static posture, while the muscles are “trained” to actively (and not reflexively) hold this posture (for example, the upper and lower Landau reflex). As the muscles are trained, the reflex gradually fades away, since the processes of central (voluntary) regulation of the posture are turned on. By the end of the period, the flexion posture becomes less pronounced. During the traction test, the extension angle increases. By the end of 3 months, postural reflexes weaken, and they are replaced by straightening reflexes of the body:

labyrinth straightening (adjusting) reflex on the head- in the position on the stomach, the head of the child is located on the middle

line, a tonic contraction of the neck muscles occurs, the head rises and is held. At first, this reflex ends with the head falling and turning it to the side (influence protective reflex). Gradually, the head can be in a raised position for longer and longer, while the legs are tense at first, but over time they begin to actively move; arms are more and more unbent at the elbow joints. A labyrinthic installation reflex is formed in a vertical position (holding the head vertically);

straightening reflex from trunk to head- when the feet touch the support, the body straightens and the head rises;

cervical rectifying reaction - with a passive or active turn of the head, the body turns.

Unconditioned reflexes still well expressed; the exception is the reflexes of support and automatic gait, which gradually begin to fade. At 1.5-2 months, the child in an upright position, placed on a hard surface, rests on the outer edges of the feet, does not make step movements when leaning forward.

By the end of 3 months, all reflexes weaken, which is expressed in their inconstancy, lengthening of the latent period, rapid exhaustion, and fragmentation. The Robinson reflex disappears. Moro's reflexes, sucking and withdrawal reflexes are still well evoked.

Combined reflex reactions appear - a sucking reflex at the sight of the breast (kinesthetic food reaction).

The range of motion increases. The athetoid component disappears, the number of active movements increases. Arises recovery complex. The first becomes possible purposeful movement: straightening the arms up, bringing the hands to the face, sucking the fingers, rubbing the eyes and nose. At the 3rd month, the child begins to look at his hands, reach out with his hands to the object - visual blink reflex. Due to the weakening of the synergy of the flexors, flexion occurs in the elbow joints without bending the fingers, the ability to hold an enclosed object in the hand.

Tendon reflexes: in addition to the knee, Achilles, bicipital are called. Abdominal reflexes appear.

Postural reactions: during the 1st month, the child raises its head for a short time, then “drops” it. Arms bent under the chest (labyrinth straightening reflex on the head, tonic contraction of the neck muscles ends with the head falling and turning it to the side -

element of a protective reflex). Direction of development: exercise to increase the time of holding the head, extension of the arms in the elbow joint, opening of the hand. At the 2nd month, the child can hold his head at an angle of 45? for some time. to the surface, while the head is still swaying uncertainly. The angle of extension in the elbow joints increases. At the 3rd month, the child confidently holds his head, lying on his stomach. Forearm support. The pelvis is down.

Walking Ability: a child of 3-5 months holds his head well in an upright position, but if you try to put him, he draws his legs and hangs on the hands of an adult (physiological astasia-abasia).

Grasping and manipulation: on the 2nd month, the brushes are slightly ajar. At the 3rd month, a small light rattle can be put into the child's hand, he grabs it and holds it in his hand, but he himself is not yet able to open the brush and release the toy. Therefore, after playing for some time and listening with interest to the sounds of the rattle that are heard when it is shaken, the child begins to cry: he gets tired of holding the object in his hand, but cannot voluntarily release it.

Social contacts: at the 2nd month, a smile appears, which the child addresses to all living beings (as opposed to inanimate ones).

Child aged 3-6 months. At this stage, the assessment of motor functions consists of the previously listed components (muscle tone, range of motion, tendon reflexes, unconditioned reflexes, voluntary movements, their coordination) and newly emerged general motor skills, in particular manipulations (hand movements).

Skills:

Increase in the period of wakefulness;

Interest in toys, looking, grasping, bringing to the mouth;

The development of facial expressions;

The appearance of cooing;

Communication with an adult: the orienting reaction turns into a complex of revival or a reaction of fear, a reaction to the departure of an adult;

Further integration (sensory-motor behavior);

Auditory reactions;

Hearing-motor reactions (turning the head towards the call);

Visual-tactile-kinesthetic (examining one's own hands is replaced by examining toys, objects);

Visual-tactile-motor (grasping objects);

Hand-eye coordination - the ability to control with a glance the movements of a hand reaching for a closely located object (feeling one's hands, rubbing, joining hands, touching one's head, while sucking, holding a breast, a bottle);

The reaction of active touch - feeling the object with your feet and grasping with their help, stretching your arms in the direction of the object, feeling; this reaction disappears when the object capture function appears;

Skin concentration reaction;

Visual localization of an object in space based on a visual-tactile reflex;

Increasing visual acuity; the child can distinguish small objects against a solid background (for example, buttons on clothes of the same color).

Muscle tone. There is a synchronization of the tone of the flexors and extensors. Now the posture is determined by a group of reflexes that straighten the body and voluntary motor activity. In a dream, the hand is open; ASHTR, SSTR, LTR have faded. The tone is symmetrical. Physiological hypertension is replaced by normotonia.

There is further formation rectifying reflexes of the body. In the position on the stomach, a steady hold of the raised head is noted, reliance on a slightly extended arm, later - reliance on the outstretched arm. The upper Landau reflex appears in the position on the stomach ("swimmer's position", i.e. raising the head, shoulders and torso in the position on the stomach with straightened arms). Head control in a vertical position is stable, sufficient in the supine position. There is a straightening reflex from the body to the body, i.e. the ability to rotate the shoulder girdle relative to the pelvic.

tendon reflexes all are called.

Developing motor skills following.

Attempts to pull the body to the outstretched arms.

Ability to sit with support.

The appearance of a "bridge" - arching of the spine based on the buttocks (feet) and head while tracking the object. In the future, this movement is transformed into an element of a turn on the stomach - a “block” turn.

Turn from back to stomach; at the same time, the child can rest with his hands, raising his shoulders and head and looking around in search of objects.

Objects are captured by the palm (squeezing the object in the palm with the help of the flexor muscles of the hand). There is no opposition of the thumb yet.

The capture of an object is accompanied by a lot of unnecessary movements (both hands, mouth, legs move at the same time), there is still no clear coordination.

Gradually, the number of extra movements decreases. Grasping an attractive object with both hands appears.

The number of movements in the hands increases: lifting up, to the sides, clutching together, feeling, putting into the mouth.

Movements in large joints, fine motor skills are not developed.

Ability to sit independently (without support) for a few seconds/minutes.

Unconditioned reflexes fade away, except for the sucking and withdrawal reflexes. Elements of the Moro reflex are preserved. The appearance of a parachute reflex (in the position of hanging by the armpits horizontally face down, as in a fall, the arms are unbent and the fingers spread apart - as if in an attempt to protect themselves from a fall).

Postural reactions: at the 4th month, the child's head is stably raised; support on an outstretched arm. In the future, this posture becomes more complicated: the head, the shoulder girdle are raised, the arms are straightened and stretched forward, the legs are straight (swimmer's position, upper Landau reflection). Lifting up the legs (lower Landau reflex), the baby can rock on the stomach and turn around it. At the 5th month, the ability to turn from the position described above onto the back appears. First, a turn from the stomach to the back occurs by chance when the arm is thrown far forward and the balance on the stomach is disturbed. Direction of development: exercises for the purposefulness of turns. At the 6th month, the head and shoulder girdle were raised above the horizontal surface at an angle of 80–90°, the arms were straightened at the elbow joints, resting on fully open hands. Such a posture is already so stable that the child can follow the object of interest by turning his head, and also transfer the body weight to one hand, and with the other hand try to reach for the object and grab it.

Ability to sit - keeping the body in a static state - is a dynamic function and requires the work of many muscles and precise coordination. This posture allows you to free your hands for fine motor actions. To learn to sit, you need to master three fundamental functions: keep your head upright in any position of the body, bend your hips, and actively rotate your torso. At the 4-5th month, when sipping on the arms, the child, as it were, “sits down”: bends his head, arms and legs. At the 6th month, the child can be planted, while for some time he will hold his head and torso vertically.

Walking Ability: at the 5-6th month, the ability to stand with the support of an adult, leaning on a full foot, gradually appears. At the same time, the legs are straightened. Quite often, the hip joints remain slightly bent in an upright position, as a result of which the child does not stand on a full foot, but on his toes. This isolated phenomenon is not a manifestation of spastic hypertonicity, but a normal stage in the formation of gait. A "jump phase" appears. The child begins to bounce when placed on its feet: an adult holds the child under the armpits, he crouches and pushes off, straightening the hips, knees and ankle joints. This causes a lot of positive emotions and, as a rule, is accompanied by loud laughter.

Grasping and manipulation: at the 4th month, the range of motion in the hand increases significantly: the child brings his hands to his face, examines them, brings them and puts them in his mouth, rubs his hand in hand, touches the other with one hand. He may accidentally grab a toy that is within reach and also bring it to his face, to his mouth. Thus, he explores the toy - with his eyes, hands and mouth. At the 5th month, the child can voluntarily take an object lying in the field of vision. At the same time, he stretches out both hands and touches him.

Social contacts: from 3 months the child begins to laugh in response to communication with him, a complex of revival and cries of joy appear (until this time, a cry occurs only with unpleasant sensations).

Child aged 6-9 months. In this age period, the following functions are noted:

Development of integrative and sensory-situational connections;

Active cognitive activity based on visual-motor behavior;

Chain motor associative reflex - listening, observing one's own manipulations;

Development of emotions;

Games;

Variety of facial movements. Muscle tone - fine. Tendon reflexes are caused by everything. Motor skills:

Development of arbitrary purposeful movements;

Development of the rectifying reflex of the body;

Turns from stomach to back and from back to stomach;

Reliance on one hand;

Synchronization of the work of antagonist muscles;

Stable independent sitting for a long time;

Chain symmetrical reflex in the position on the stomach (the basis of crawling);

Crawling back, in a circle, with the help of pull-ups on the hands (legs do not participate in crawling);

Crawling on all fours with lifting the body above the support;

Attempts to accept vertical posture- when sipping on the hands from a supine position, he immediately rises to straightened legs;

Attempts to get up, holding hands on a support;

The beginning of walking along the support (furniture);

Attempts to sit down independently from an upright position;

Attempts to walk while holding the hand of an adult;

Plays with toys, II and III fingers participate in manipulations. Coordination: coordinated clear hand movements; at

manipulations in the sitting position, a lot of unnecessary movements, instability (i.e. arbitrary actions with objects in the sitting position are a load test, as a result of which the position is not maintained and the child falls).

Unconditioned reflexes extinguished, except for the suckling.

Postural reactions: at the 7th month, the child is able to turn from his back to his stomach; for the first time, on the basis of the rectifying reflex of the body, the ability to sit down independently is realized. At the 8th month, turns are improved, and the phase of crawling on all fours develops. At the 9th month, the ability to purposefully crawl with support on the hands appears; leaning on the forearms, the child pulls the entire body.

Ability to sit: at the 7th month, the child lying on his back assumes a “sitting” position, bending his legs at the hip and knee joints. In this position, the child can play with his legs and pull them into his mouth. At 8 months, a seated baby can sit on its own for several seconds, and then “fall over” on its side, leaning with one hand on the surface to protect itself from falling. At the 9th month, the child sits for a longer time on his own with a “round back” (lumbar lordosis has not yet been formed), and when tired, he leans back.

Walking Ability: at the 7-8th month, a reaction of support on the hands appears if the child is sharply tilted forward. At the 9th month, a child placed on the surface and supported by the arms stands independently for several minutes.

Grasping and manipulation: on the 6-8th month, the accuracy of capturing the object improves. The child takes it with the entire surface of the palm. Can transfer an item from one hand to the other. At the 9th month, he voluntarily releases the toy from his hands, it falls, and the child carefully follows the trajectory of its fall. He likes it when an adult picks up a toy and gives it to a child. Releases the toy again and laughs. Such an activity, according to an adult, is a stupid and meaningless game, in fact it is a complex training of hand-eye coordination and a complex social act - a game with an adult.

Child aged 9-12 months. This age period includes:

Development and complication of emotions; the revitalization complex fades away;

Various facial expressions;

Sensory speech, understanding of simple commands;

The appearance of simple words;

Story games.

Muscle tone, tendon reflexes remain unchanged in comparison with the previous stage and throughout the rest of life.

Unconditioned reflexes everything faded away, the sucking reflex fades.

Motor skills:

Improvement of complex chain reflexes of verticalization and voluntary movements;

Ability to stand at a support; attempts to stand without support, on their own;

The appearance of several independent steps, the further development of walking;

Repeated actions with objects (“memorization” of motor patterns), which can be considered as the first step towards the formation of complex automated movements;

Purposeful actions with objects (inserting, putting on).

The formation of the gait children are very variable and individual. Manifestations of character and personality are clearly demonstrated in attempts to stand, walk and play with toys. In most children, by the beginning of walking, the Babinski reflex and the lower grasping reflex disappear.

Coordination: immaturity of coordination in making vertical position leading to falls.

Perfection fine motor skills: grasping small objects with two fingers; there is opposition between the thumb and little finger.

In the 1st year of a child's life, the main directions of motor development are distinguished: postural reactions, elementary movements, crawling on all fours, the ability to stand, walk, sit, grasping abilities, perception, social behavior, making sounds, understanding speech. Thus, there are several stages in development.

Postural reactions: at the 10th month, in the position on the stomach with a raised head and support on the hands, the child can simultaneously raise the pelvis. Thus, it rests only on the palms and feet and sways back and forth. At the 11th month, he begins to crawl with support on his hands and feet. Further, the child learns to crawl in a coordinated way, i.e. alternately extending the right arm - the left leg and the left arm - the right leg. At the 12th month, crawling on all fours becomes more and more rhythmic, smooth, and fast. From this moment, the child begins to actively explore and explore his home. Crawling on all fours is a primitive form of movement, atypical for adults, but at this stage the muscles are prepared for the following stages of motor development: muscle strength increases, coordination and balance are trained.

The ability to sit is formed individually from 6 to 10 months. This coincides with the development of the pose on all fours (support on the palms and feet), from which the child easily sits down, turning the pelvis relative to the body ( rectifying reflex from the pelvic girdle to the torso). The child sits independently, stably with a straight back and legs straightened at the knee joints. In this position, the child can play for a long time without losing balance. Next, seat

becomes so stable that the child can perform extremely complex actions while sitting, requiring excellent coordination: for example, holding a spoon and eating with it, holding a cup with both hands and drinking from it, playing with small objects, etc.

Walking Ability: at the 10th month, the child crawls to the furniture and, holding on to it, gets up on its own. At the 11th month, the child can walk along the furniture, holding on to it. At the 12th month, it becomes possible to walk, holding on with one hand, and, finally, to take several independent steps. In the future, coordination and strength of the muscles involved in walking develop, and walking itself improves more and more, becoming faster, more purposeful.

Grasping and manipulation: on the 10th month, a “tweezer-like grip” appears with opposition of the thumb. The child can take small items, while he pulls out a large and index fingers and holds the object with them, like tweezers. At the 11th month, a “pincer grip” appears: the thumb and forefinger form a “claw” during grip. The difference between the pincer grip and the claw grip is that the former has straight fingers while the latter has bent fingers. At the 12th month, a child can accurately put an object into a large dish or an adult's hand.

Social contacts: by the 6th month, the child distinguishes "friends" from "strangers". At 8 months, the child begins to be afraid of strangers. He no longer allows everyone to take him in his arms, touch him, turns away from strangers. At 9 months, the child begins to play hide-and-seek - peek-a-boo.

10.2. Examination of a child from the neonatal period to six months

When examining a newborn baby, his gestational age should be taken into account, because even a slight immaturity or prematurity of less than 37 weeks can significantly affect the nature of spontaneous movements (movements are slow, generalized with tremor).

Muscle tone is changed, and the degree of hypotension is directly proportional to the degree of maturity, usually in the direction of its decrease. A full-term baby has a pronounced flexor posture (reminiscent of an embryonic one), and a premature baby has an extensor posture. A full-term baby and a child with prematurity of the 1st degree hold the head for a few seconds when pulling the handles, children with prematurity

a deeper degree and children with damaged central nervous system do not hold their heads. It is important to determine the severity of physiological reflexes in the neonatal period, especially grasping, suspension, as well as reflexes that provide sucking, swallowing. When examining the function of the cranial nerves, it is necessary to pay attention to the size of the pupils and their reaction to light, the symmetry of the face, and the position of the head. Most healthy newborns fix their gaze on the 2-3rd day after birth and try to follow the object. Symptoms such as Graefe's symptom, nystagmus in the extreme leads are physiological and are due to the immaturity of the posterior longitudinal bundle.

Severe edema in a child can cause depression of all neurological functions, but if it does not decrease and is combined with liver enlargement, a congenital form of hepatocerebral dystrophy (hepatolenticular degeneration) or lysosomal disease should be suspected.

Specific (pathognomonic) neurological symptoms characteristic of dysfunction of a particular area of ​​the CNS are absent until 6 months of age. The main neurological symptoms are usually impaired muscle tone with or without motor deficits; communication disorders, which are determined by the ability to fix the gaze, follow objects, single out acquaintances, etc., and reactions to various stimuli: the more clearly visual control is expressed in a child, the more perfect his nervous system. Great importance is attached to the presence of paroxysmal epileptic phenomena or their absence.

The exact description of all paroxysmal phenomena is the more difficult, the smaller the age of the child. Convulsions that occur in this age period are often polymorphic.

The combination of altered muscle tone with movement disorders (hemiplegia, paraplegia, tetraplegia) indicates a gross focal lesion of the brain substance. In about 30% of cases of hypotension of central origin, no cause can be found.

Anamnesis and somatic symptoms are of particular importance in newborns and children under 4 months due to the paucity of neurological examination data. For example, respiratory disorders at this age can often be the result of CNS damage and occur with

congenital forms of myatonia and spinal amyotrophy. Apnea and dysrhythmia may be due to abnormalities of the brainstem or cerebellum, Pierre Robin's anomaly, and metabolic disorders.

10.3. Examination of a child aged 6 months to 1 year

In children from 6 months to 1 year, both acute neurological disorders with a catastrophic course and slowly progressive ones often occur, so the doctor must immediately outline the range of diseases that can lead to these conditions.

The appearance of febrile and unprovoked convulsions such as infantile spasms is characteristic. Movement disorders are manifested by a change in muscle tone and its asymmetry. In this age period, such congenital diseases as spinal amyotrophy and myopathy clearly manifest themselves. The doctor must remember that the asymmetry of the muscle tone of a child of this age may be due to the position of the head in relation to the body. The lag in psychomotor development may be the result of metabolic and degenerative diseases. Emotional disorders - poverty of facial expressions, lack of a smile and loud laughter, as well as pre-speech development disorders (babbling formation) are caused by hearing impairment, brain underdevelopment, autism, degenerative diseases of the nervous system, and when combined with skin manifestations- tuberous sclerosis, which is also characterized by motor stereotypes and convulsions.

10.4. Examination of a child after the 1st year of life

The progressive maturation of the central nervous system causes the appearance of specific neurological symptoms indicating a focal lesion, and it is possible to determine the dysfunction of a particular area of ​​the central or peripheral nervous system.

The most common reasons for visiting a doctor are a delay in the development of gait, its violation (ataxia, spastic paraplegia, hemiplegia, diffuse hypotension), walking regression, hyperkinesis.

Combination of neurological symptoms with extraneural (somatic) ones, their slow progression, development of skull and face dysmorphias, lag in mental development and violation of emotions should prompt the doctor to the idea of ​​the presence of metabolic diseases - mucopolysaccharidosis and mucolipidosis.

The second most common reason for treatment is mental retardation. A gross lag is observed in 4 out of 1000 children, and in 10-15% this delay is the cause of learning difficulties. It is important to diagnose syndromal forms, in which oligophrenia is only a symptom of general underdevelopment of the brain against the background of dysmorphias and multiple developmental anomalies. Impairment of intelligence may be due to microcephaly, the cause of developmental delay can also be progressive hydrocephalus.

Cognitive disorders in combination with chronic and progressive neurological symptoms in the form of ataxia, spasticity or hypotension with high reflexes should prompt the doctor to think about the onset of mitochondrial disease, subacute panencephalitis, HIV encephalitis (in combination with polyneuropathy), Creutzfeldt-Jakob disease. Impairment of emotions and behavior, combined with cognitive deficits, suggests the presence of Rett syndrome, Santavuori's disease.

Sensorineural disorders (visual, oculomotor, auditory) are very widely represented in childhood. There are many reasons for their appearance. They may be congenital, acquired, chronic or developing, isolated or associated with other neurological symptoms. They can be caused by embryofetal brain damage, an anomaly in the development of the eye or ear, or these are the consequences of previous meningitis, encephalitis, tumors, metabolic or degenerative diseases.

Oculomotor disorders in some cases are the result of damage to the oculomotor nerves, including congenital anomaly Graefe-Möbius.

From 2 years oldthe frequency of occurrence increases sharply febrile seizures, which by the age of 5 should completely disappear. After 5 years, epileptic encephalopathy debuts - syndrome Lennox-Gasteau and most childhood idiopathic forms of epilepsy. Acute onset of neurological disorders with impaired consciousness, pyramidal and extrapyramidal neurological symptoms, debuting against the background of febrile condition, especially with concomitant purulent diseases in the face (sinusitis), should raise suspicion of bacterial meningitis, brain abscess. These conditions require urgent diagnosis and specific treatment.

At a younger age malignant tumors also develop, most often of the brainstem, cerebellum and its worm, the symptoms of which can develop acutely, subacutely, often after children stay in southern latitudes, and manifest not only headache, but also dizziness, ataxia due to occlusion of the CSF pathways.

It is not uncommon for blood diseases, in particular lymphomas, to debut with acute neurological symptoms in the form of opsomyoclonus, transverse myelitis.

In children after 5 years most common cause going to the doctor is a headache. If she wears a special stubborn chronic, accompanied by dizziness, neurological symptoms, especially cerebellar disorders (static and locomotor ataxia, intention tremor), it is necessary first of all to exclude a brain tumor, mainly a tumor of the posterior cranial fossa. These complaints and the listed symptoms are an indication for CT and MRI studies of the brain.

Slowly progressive development of spastic paraplegia, sensory disorders in the presence of asymmetry and dysmorphias of the trunk may raise the suspicion of syringomyelia, and the acute development of symptoms - hemorrhagic myelopathy. Acute peripheral paralysis with radicular pain, sensory disturbance and pelvic disorders are characteristic of polyradiculoneuritis.

Delays in psychomotor development, especially in combination with the breakdown of intellectual functions and progressive neurological symptoms, occur against the background of metabolic and neurodegenerative diseases at any age and have different rates of development, but in this age period it is very important to know that impairment of intellectual functions and motor skills and speech may be a consequence of epileptiform encephalopathy.

progressive neuromuscular diseases debut in different time with gait disorders, muscle atrophy and changes in the shape of the feet and legs.

In older children, more often in girls, there may be episodic attacks of dizziness, ataxia with sudden visual impairment and the appearance of seizures, which at first

difficult to distinguish from epileptic. These symptoms are accompanied by changes in the affective sphere of the child, and observations of family members and assessment of their psychological profile make it possible to reject the organic nature of the disease, although in isolated cases additional research methods are required.

In this period, various forms of epilepsy, infections and autoimmune diseases of the nervous system often debut, less often - neurometabolic. Circulatory disorders may also occur.

10.5. Formation of pathological postural activity and movement disorders in early organic brain damage

Violation of the child's motor development is one of the most common consequences of damage to the nervous system in the ante- and perinatal period. The delay in the reduction of unconditioned reflexes leads to the formation of pathological postures and attitudes, inhibits and distorts further motor development.

As a result, all this is expressed in a violation of the motor function - the appearance of a complex of symptoms, which by the 1st year is clearly formed into the syndrome of infantile cerebral palsy. Components of the clinical picture:

Damage to motor control systems;

Delayed reduction of primitive postural reflexes;

Delay in general development, including mental;

Violation of motor development, sharply enhanced tonic labyrinth reflexes, leading to the appearance of reflex-protective positions, in which the “embryonic” posture is maintained, a delay in the development of extensor movements, chain symmetrical and adjusting reflexes of the body;

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The nervous system regulates the physiological functions of the body in accordance with changing external conditions and maintains a certain constancy of its internal environment at a level that ensures vital activity. And understanding the principles of its functioning is based on knowledge of the age-related development of the structures and functions of the brain. In the life of a child, the constant complication of the forms of nervous activity is aimed at the formation of an increasingly complex adaptive ability of the organism, corresponding to the conditions of the surrounding social and natural environment.
Thus, the adaptive capacity of the growing human body determined by the level of age organization of his nervous system. The simpler it is, the more primitive its answers, which boil down to simple defensive reactions. But with the complication of the structure of the nervous system, when the analysis of environmental influences becomes more differentiated, the child's behavior also becomes more complicated, and the level of his adaptation increases.

How does the nervous system mature?

In the mother's womb, the embryo receives everything that it needs, is protected from any adversity. And during the period of maturation of the embryo, 25,000 nerve cells are born in its brain every minute (the mechanism of this amazing process is unclear, although it is clear that a genetic program is being implemented). Cells divide and form organs while the growing fetus floats in the amniotic fluid. And through the maternal placenta, he continuously, without any effort, receives food, oxygen, and toxins are removed from his body in the same way.
The nervous system of the fetus begins to develop from the outer germ layer, from which the neural plate, groove, and then the neural tube are first formed. In the third week, three primary cerebral vesicles form from it, two of which (anterior and posterior) divide again, resulting in the formation of five cerebral vesicles. From each cerebral bladder, various parts of the brain subsequently develop.
Further separation occurs during fetal development. The main parts of the central nervous system are formed: hemispheres, subcortical nuclei, trunk, cerebellum and spinal cord: the main furrows of the cerebral cortex are differentiated; the predominance of the higher parts of the nervous system over the lower ones becomes noticeable.
As the fetus develops, many of its organs and systems conduct a kind of “dress rehearsal” even before their functions become really necessary. So, for example, contractions of the heart muscle occur when there is still no blood and the need to pump it; peristalsis of the stomach and intestines appears, gastric juice, although there is still no food as such; V complete darkness eyes open and close; arms and legs move, which gives the mother indescribable joy from the sensation of life emerging in her; a few weeks before birth, the fetus even begins to breathe in the absence of air to breathe.
By the end of the prenatal period, the overall structure of the central nervous system is almost fully developed, but the adult brain is much more complex than the brain of a newborn.

Development of the human brain: A, B - at the stage of cerebral vesicles (1 - terminal; 2 intermediate; 3 - middle, 4 - isthmus; 5 - posterior; 6 - oblong); B - the brain of the embryo (4.5 months); G - newborn; D - adult

The brain of a newborn is approximately 1/8 of the body weight and weighs an average of about 400 grams (boys have a little more). By 9 months, the mass of the brain doubles, by the age of 3 it triples, and at the age of 5 the brain is 1/13 - 1/14 of the body weight, by the age of 20 - 1/40. The most pronounced topographic changes in various parts of the growing brain occur in the first 5-6 years of life and end only by the age of 15-16.
Previously, it was believed that by the time of birth, the child's nervous system has a complete set of neurons (nerve cells) and develops only by complicating the connections between them. It is now known that in some formations of the temporal lobe of the hemispheres and the cerebellum, up to 80-90% of neurons are formed only after birth with an intensity that depends on the influx of sensory information (from the sense organs) from the external environment.
The activity of metabolic processes is very high in the brain. Up to 20% of all blood sent by the heart to the arteries great circle blood circulation, flows through the brain, consuming a fifth of the oxygen absorbed by the body. High speed blood flow in the cerebral vessels and its saturation with oxygen are necessary primarily for the vital activity of the cells of the nervous system. Unlike the cells of other tissues, the nerve cell does not contain any energy reserves: the oxygen and nutrition supplied with the blood are consumed almost instantly. And any delay in their delivery is in danger, if the oxygen supply is cut off for only 7-8 minutes. nerve cells are dying. On average, an influx of 50-60 ml of blood is needed per 100 g of medulla in one minute.

The proportions of the bones of the skull of a newborn and an adult

Corresponding to an increase in the mass of the brain, significant changes occur in the proportions of the bones of the skull in the same way as the proportion of body parts changes in the process of growth. The skull of newborns is not completely formed, and its sutures and fontanelles may still be open. In most cases, by birth, a diamond-shaped opening at the junction of the frontal and parietal bones (large fontanelle) remains open, which usually closes only by the age of one, the child’s skull is actively growing, while the head is increasing in circumference.
This happens most intensively in the first three months of life: the head increases in circumference by 5-6 cm. Later, the pace slows down, and by the year it increases by a total of 10-12 cm. Usually in a newborn (weighing 3-3.5 kg ) head circumference is 35-36 cm, reaching 46-47 cm by one year. Further, head growth slows down even more (does not exceed 0.5 cm per year). Excessive growth of the head, as well as its noticeable lag, indicates the possibility of development pathological phenomena(particularly hydrocephalus or microcephaly).
With age, the spinal cord also undergoes changes, the length of which in a newborn is on average about 14 cm and doubles by 10 years. Unlike the brain, the spinal cord of a newborn has a more functionally perfect, complete morphological structure, almost completely occupying the space of the spinal canal. With the development of the vertebrae, the growth of the spinal cord slows down.
Thus, even during normal intrauterine development, normal delivery a child is born, albeit with a structurally formed, but immature nervous system.

What do reflexes give the body?

The activity of the nervous system is basically reflex. Under the reflex understand the response to the impact of an irritant from the external or internal environment of the body. To implement it, a receptor with a sensitive neuron that perceives irritation is needed. The response of the nervous system comes ultimately to the motor neuron, which reflexively reacts, prompting or “slowing down” the organ innervated by it, the muscle, to activity. This simple chain is called reflex arc, and only when it is preserved can a reflex be realized.
An example is the reaction of a newborn to a slight dashed irritation of the corner of the mouth, in response to which the child turns his head towards the source of irritation and opens his mouth. The arc of this reflex is, of course, more complex than, for example, the knee-jerk reflex, but the essence is the same: in response to irritation reflex zone the child has search head movements and readiness to suck.
There are simple reflexes and complex ones. As can be seen from the example, the search and sucking reflexes are complex, and the knee reflex is simple. At the same time, congenital (unconditioned) reflexes, especially during the neonatal period, are in the nature of automatisms, mainly in the form of food, protective and postural tonic reactions. Such reflexes in humans are provided on different "floors" of the nervous system, therefore, spinal, stem, cerebellar, subcortical and cortical reflexes are distinguished. In a newborn child, taking into account the unequal degree of maturity of the parts of the nervous system, reflexes of spinal and stem automatisms predominate.
During individual development and the accumulation of new skills due to the development of new temporary connections with the obligatory participation of the higher parts of the nervous system, conditioned reflexes are formed. big hemispheres The brain plays a special role in the formation of conditioned reflexes, which are formed on the basis of innate connections in the nervous system. Therefore, unconditioned reflexes exist not only on their own, but as a constant component they enter into all conditioned reflexes and the most complex acts of life.
If you look closely at the newborn, then the chaotic nature of the movements of his arms, legs, and head attracts attention. The perception of irritation, for example, on the leg, cold or pain, does not give an isolated withdrawal of the leg, but a general (generalized) motor reaction of excitation. The maturation of structure is always expressed in the improvement of function. This is most noticeable in the formation of movements.
It is noteworthy that the first movements in a fetus of three weeks of age (length 4 mm) are associated with heart contractions. A motor reaction in response to skin irritation appears from the second month of intrauterine life, when the nerve elements of the spinal cord are formed, which are necessary for reflex activity. At the age of three and a half months, the fetus can show most of the physiological reflexes observed in newborns, with the exception of screaming, grasping reflex and breathing. With the growth of the fetus and an increase in its mass, the volume of spontaneous movements also becomes large, which can be easily verified by causing the fetus to move by careful tapping on the mother's abdomen.
In development motor activity child, two interrelated patterns can be traced: the complication of functions and the extinction of a number of simple, unconditioned, innate reflexes, which, of course, do not disappear, but are used in new, more complex movements. The delay or late extinction of such reflexes indicates a lag in motor development.
The motor activity of a newborn and a child in the first months of life is characterized by automatisms (sets of automatic movements, unconditioned reflexes). With age, automatisms are replaced by more conscious movements or skills.

Why do we need motor automatisms?

The main reflexes of motor automatism are food, protective spinal, tonic position reflexes.

Food motor automatisms provide the child with the ability to suck and search for a source of food for him. The preservation of these reflexes in the newborn indicates normal function nervous system. Their manifestation is as follows.
When pressing on the palm, the child opens his mouth, turns or bends his head. If you apply a light blow with your fingertips or a wooden stick on the lips, in response they are drawn into a tube (therefore, the reflex is called proboscis). When stroking in the corner of the mouth, the child has a search reflex: he turns his head in the same direction and opens his mouth. The sucking reflex is the main one in this group (characterized by sucking movements when a nipple, breast nipple, finger enters the mouth).
If the first three reflexes normally disappear by 3-4 months of life, then sucking - by one year. These reflexes are most actively expressed in a child before feeding, when he is hungry; after eating, they may fade somewhat, as a well-fed child calms down.

Spinal motor automatisms appear in a child from birth and persist for the first 3-4 months and then fade away.
The simplest of these reflexes is the defensive reflex: if the child is placed face down on his stomach, he will quickly turn his head to the side, facilitating his breathing through his nose and mouth. The essence of another reflex is that in the position on the stomach, the child makes crawling movements if a support (for example, a palm) is placed on the soles of the feet. Therefore, the inattentive attitude of parents to this automatism can end sadly, since a child left unattended by his mother on the table can, resting his feet on something, push himself to the floor.

Let's check the reflexes: 1 - palmar-mouth; 2 - proboscis; 3 - search; 4 - sucking

The tenderness of parents causes the ability of a tiny man to lean on his legs and even walk. These are support reflexes and automatic walking. To check them, you should lift the child, holding him under the arms, and put him on a support. Feeling the surface with the soles of the feet, the child will straighten the legs and rest against the table. If he is slightly tilted forward, he will take a reflex step with one and then the other foot.
From birth, a child has a well-defined grasping reflex: the ability to hold the fingers of an adult well placed in his palm. The force with which he grasps is sufficient to hold himself, and he can be lifted up. The grasping reflex in newborn monkeys allows the cubs to keep themselves on the mother's body when she moves.
Sometimes parental anxiety is caused by scattering of the child's arms during various manipulations with him. Such reactions are usually associated with the manifestation of an unconditioned grasping reflex. It can be caused by any stimulus of sufficient strength: by patting on the surface on which the child lies, by raising the extended legs above the table, or by quickly extending the legs. In response to this, the baby spreads the arms to the sides and opens the fists, and then returns them to their original position again. With increased excitability of the child, the reflex increases, being caused by stimuli such as sound, light, a simple touch or swaddling. The reflex fades after 4-5 months.

Tonic position reflexes. In newborns and children of the first months of life, reflex motor automatisms associated with a change in the position of the head appear.
For example, turning it to the side leads to a redistribution of muscle tone in the limbs so that the arm and leg, to which the face is turned, unbend, and the opposite ones bend. In this case, the movements in the arms and legs are asymmetrical. When the head is bent to the chest, the tone in the arms and legs increases symmetrically and leads them to flexion. If the child's head is straightened, then the arms and legs will also straighten due to an increase in tone in the extensors.
With age, at the 2nd month, the child develops the ability to hold his head, and after 5-6 months he can turn from his back to his stomach and vice versa, and also hold the “swallow” position if he is supported (under the stomach) by hand.

Let's check the reflexes: 1 - protective; 2 - crawling; 3 - support and automatic walking; 4 - grasping; 5 - hold; 6 - wraps

In the development of motor functions in a child, a descending type of formation of movement can be traced, that is, at the beginning of the movement of the head (in the form of its vertical setting), then the child forms the support function of the hands. When turning from back to stomach, the head first turns, then the shoulder girdle and then the torso and legs. Later, the child masters leg movements - support and walking.

Let's check the reflexes: 1 - asymmetric cervical tonic; 2 - symmetrical cervical tonic; 3 - holding the head and legs in the "swallow" position

When, at the age of 3-4 months, a child, who had previously been able to lean well on his legs and take steps with support, suddenly loses this ability, the anxiety of the parents makes them go to the doctor. Fears are often unfounded: at this age, the reflex reactions of support and the stepping reflex disappear and are replaced by the development of vertical standing and walking skills (by 4-5 months of life). This is how the “program” of mastering movements during the first year and a half of a child’s life looks like. Motor development provides the ability to hold the head by 1-1.5 months, purposeful hand movements - by 3-4 months. At about 5-6 months, the child grasps objects well in his hand and holds them, he can sit and he becomes ready to stand. At 9-10 months, he will already begin to stand with support, and at 11-12 months he can move with outside help and on his own. Uncertain at first, the gait becomes more and more stable, and by 15-16 months the child rarely falls while walking.