Bone system in children
Bone system of children.It is formed from the middle embryonic leaf (mesoderm) at the 5th week. embryonic development. The final structure of the bones is formed after the birth of the child and coincides with the onset of sustainable walking. Bone tissue in newborns has a porous coarse-lobed structure, a few bone plates are located incorrectly, Havers canals appear to be disorderly scattered cavities. In the bone, there is a lot of water and a little dense substance (ash is 1/2 the mass of the bone of the newborn, in the adult it is 4/5), and the children's bones are soft, elastic, less fragile, but easily deformed.
The vascular channels in the bone are wide, which contributes to the rich supply of its blood and the vigorous course of osteoblastic and osteoclastic processes, which ensure growth, but at the same time, the spread in the immature bone of the inflammatory processes. As it grows, the bone remodeling occurs with the replacement of the fibrous mesh structure of the lamellar one.Between the diaphysis and the epiphysis of the tubular bones, the cartilage growth plate is preserved for a long time, due to which the bone grows in length. Bone thickening occurs on the part of the periosteum, while the cortical layer undergoes constant resorption, as a result of which the volume of the bone marrow space increases. In the process of osteogenesis (bone formation and remodeling), 3 stages are distinguished. In the 1st, an intensive anabolic process takes place, during which protein base of bone tissue is created.
For this process, it is necessary to provide the child with protein, vitamins A, C, group B. In the 2nd stage, the formation of crystallization centers of hydroxyappatite occurs, followed by osteoid mineralization, as a result of which the body is provided with calcium, phosphorus, microelements (fluorine, zinc, copper, etc. .), vitamin D at this time is crucial. Both of these stages are regulated by muscle tone, movement, massage and gymnastics also contribute to osteogenesis. Stage 3 - processes of remodeling and permanent self-renewal of the bone, regulated by the activity of the parathyroid glands and dependent on the body's availability of vitamin D.Changes in the bone are most pronounced in the first 2 years of life, in the early school years and in the period of half-maturation. By the age of 12, the bones of a child are not much different from those of an adult. To judge the state of the processes of ossification in pediatric. practice studies are conducted radiographs of the hands and distal forearms (table).
Earlier appearance of ossification points indicates acceleration; later, on retardation (prirachite, dystrophy). The process of ossification is also characterized by the timing of the eruption of the teeth. In newborns and infants, the skull is relatively large, the sutures of the skull are wide and non-growing (their closure occurs by 3-4 months). In full-term infants, lateral roots are usually closed; the small one closes no later than 2-3 months, the big one - by 12-16 months. of life. The backbone of newborns is deprived fiziol. bends.
The neck curve is formed immediately after the start of holding the head. Thoracic bend (kyphosis) is established after 6-7 months. life, and finally fixed only in 6-7 years. Lumbar lordosis becomes noticeable after 9–12 months. It is finally formed in school years. In general, in children.aged spinal fixation is imperfect, and under the influence of insufficient muscular development, inadequate posture, inappropriate growth of furniture for the child, changes in the shape of the spinal column (scoliosis) are very easy. The newborn's chest is wide and short, with horizontal ribs. The transverse diameter is 25% more than the mid-length (in the max, inspiratory position). Later, the chest grows in length, the leading ends of the ribs descend, the lateral diameter increases intensively (by the age of 12, it is in the position of max, exhalation). The bones of the pelvis in young children are relatively small. The shape of the pelvis resembles a funnel. Pelvic bone growth occurs intensively up to 6 years; from 6 to 12, relative stabilization of pelvic dimensions is observed, then in girls - its most intensive development (finishes, ossification occurs only to 25 years), in young men - moderate growth.