Physical parameters of a child from 1 to 1.5 years of age

The human body has different proportions at different periods of life. The head, torso, arms and legs are in constant proportions for each age. Of course, there are individual fluctuations (depending on gender, race, etc.), but the limits of these fluctuations are relatively small, so people of the same age, on average, have the same body proportions. And if this proportionality is violated, then we perceive it as a violation of harmony or an aesthetic flaw.

According to general canons, in a correctly built human body, the length of the head is 8 times less than the length of the entire body and 3 times less than the length of the torso. The length of the arms is 3.25, and the legs are 4.25 times the length of the head. The body of a child has completely different proportions. Thus, in a newborn, the length of the head is only 4 times less than the length of his body, the length of the arms is 1.6, and the length of the legs is 2.5 of the length of the head. By the age of one year, these ratios change. The length of the head fits into the length of the body about 5 times, and the length of the arms is equal to the length of the legs. Thus, a child (compared to an adult) is a short-legged and short-armed creature with a large head and large eyes. (During the period of human growth - from childhood to adulthood - the eyes grow much more slowly than other parts of the body. Therefore, relative to the proportions of the head, children have much larger eyes than adults.)

This phenomenon is used by cartoonists. If they want their character to evoke affection, love and other pleasant emotions, they depict it with the proportions of a child - a large head, huge eyes with long eyelashes, short paws (or arms and legs). And vice versa - an evil character is always drawn in the proportions of an adult.

Let's move from proportions to absolute values. After a child turns one year old, the rate of his physical development slows down somewhat. His body weight increases on average by only 30-50 g per week.

At one year of age, the head circumference of a child reaches an average of 46.6 cm, by one and a half years it increases to 48 cm, and in two-year-olds to 49 cm. Thus, during the second year of life, the head circumference increases by 2 cm. To determine whether a child is developing correctly, along with weight and body length, its proportionality is also determined. For example, it is considered that a child's chest circumference is greater than the head circumference by as many centimeters as the child is old.

Legs grow in length much faster than arms. While a newborn's arms are slightly longer than its legs, by the age of one the limbs become the same length, and a two-year-old's legs are already longer than its arms. Let's look at a child's skull. It is divided into the facial and cerebral parts. The cerebral part of the skull is much larger than the facial part, especially in newborns. With age, the entire skull grows, but its facial part grows much faster than the cerebral part. Of particular importance for appearance is the growth of the lower jaw. This bone consists of a bony arch and branches extending from it. The angle formed by the branches and the arch changes with age from obtuse to right. At the same time, in women, the shape of the lower jaw (like the entire skull as a whole) in adulthood is very similar to that of a child.

The child's body weight changes. During this period, it increases by about 200-250 g per month, which is about 2.5-3 kg per year. And height increases by 12 cm, and it slows down with each month. Sometimes it can even stop and remain unchanged for 1-3 months. This may depend on nutrition, environment and other factors. However, both height and body weight depend to a greater extent on heredity.

Between one year and 18 months, four premolars usually appear. And between 16 and 24 months, the canines erupt. The order of teeth eruption can be disrupted, but on average, by the 25th month of life, a child should have 20 baby teeth.

Sometimes teething can be accompanied by local pain, salivation, irritability, and loss of appetite.

Despite the fact that a child between one and one and a half years of age already stands and walks well, the structure of his body does not yet fully correspond to the function of upright walking, which distinguishes man from higher animals.

The thing is that the feet of his short legs are still very small, and his head is large and heavy. The muscles of the neck, back, and legs are not yet strong. All this makes it difficult to maintain balance. In addition, the child's vestibular system is not yet sufficiently developed.

The spine of an adult has several physiological curves that make standing and walking easier. These curves are called lordoses and kyphoses. Lordosis is a forward curve. Kyphosis is a backward curve. An adult has cervical lordosis, thoracic kyphosis, lumbar lordosis, and sacrococcygeal kyphosis. Physiological curves serve as a kind of shock absorber, softening the shaking of the body when walking, running, and jumping.

In children, especially small children, the spine does not have all these curves. In addition, it is not yet strong, its ligamentous apparatus is not fully formed and begins to ossify only by the end of preschool age. And the curves of the spine are formed and fixed on average by 13-15 years. Moreover, their formation occurs sequentially. In a newborn, the spine has the shape of an almost straight column. When the baby begins to hold his head and the neck muscles are included in the work, cervical lordosis begins to form. Later, when the child begins to sit, thoracic kyphosis appears. And after the child begins to stand and walk, lumbar lordosis is formed. But even at this time, when the child lies down, his spine straightens again, since it has not yet reached the required degree of ossification.

In general, a child's bones reach full maturity only by puberty. Before that, the surface layer of a child's bone - the periosteum - is much thicker than in adults. That's why "green stick" fractures are very common in children. Have you ever broken green young shoots of bushes? Remember how it happened: the stem broke inside, but the thick, juicy skin on the outside holds it and is almost intact. Subperiosteal fractures in children are similar. In addition, the bones of the hand and foot have a cartilaginous base for a long time and ossify at a certain time.

The cardiovascular, respiratory and digestive systems do not undergo any noticeable changes during these six months (from one to one and a half years). Thus, the heart rate remains at about 120 per minute, the breathing rate is not less than 30 breaths per minute. As for the gastrointestinal tract, it continues to work the same way, unless, of course, you have not introduced shashlik, barbecue, lard with garlic and other meat products into the child's diet that are not intended for this age.

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