Age features of the spine are normal

The spine is one of the most complex organs of the human body. On the one hand - this is the main organ of the axial skeleton, performing the supporting, motor and protective functions, on the other - it is the aggregate of many spinal-motor segments, each of which is an independent anatomical formation and participates in performing the same functions. At the same time, the anatomical structure of the vertebrae, as well as their role in the performance of various functions, varies with the level of the spinal column.

The growth and development of the spine in the process of life is not just a mechanical increase in its size and weight - with age, the cartilaginous parts of the vertebrae are replaced by bone, as the person moves to a vertical position, physiological spinal cords are formed, the structure of intervertebral discs and subchondral parts of the vertebrae changes. In the first two decades of life, the development of the spine is so dynamic that even small time intervals can correspond to very pronounced changes in its structure. That is why we considered it necessary to focus on the age specific features of normal development of the spine. This section presents some clinical, anatomical, anthropometric data, as well as information on the radiographic parameters characterizing the physiological development of the spine and used to assess its normal growth and overall formation, as well as to assess the normal development of the departments and segments of the spinal column. The deviation of the values of these parameters from the average physiological, although it may be due to individual characteristics, but more often is a sign of disease. Understanding the peculiarities of normal spine growth is of great practical importance: it is with periods of the most intensive physiological growth that in most cases the progression of the so-called idiopathic (ie, without obvious cause) deformations of the spine coincides.

[1], [2], [3], [4], [5], [6]

Age features of spine growth

The main human anthropometric indicators are body weight and overall height. The latter consists of the height of the head, trunk and length of the lower limbs. And although this "folding" is very conditional, since it does not take into account the partial "overlap" of segments, however, it is the correct ratio of these indicators that characterizes the normal and proportional growth of the spine.

It is known that the proportions of the human body vary significantly from the period of the newborn to the mature age. The length (growth) of a newborn is characterized by a relatively large size of the head and trunk. To assess the proportionality of the development of the human body, the conditional division of body length into the upper and lower halves is used, while two indicators are primarily evaluated and compared: the intensity of the annual increase in total human growth (the so-called annual increase in body length) and the ratio of the height of the person in the sitting position to growth in the standing position (the so-called growth factor).

The increase in the total length of the body in the course of life occurs due to the growth of predominantly lower extremities, less significantly - due to the spine and only slightly due to the increase in the size of the head. The dynamics of the annual increase in the total length of the body (taking into account gender differences) is reflected in the scheme of RA. Zorab'a. Along with the relatively monotonous period, which lasts from the 4th to the 5th to the 12th year of life and is characterized by an average annual increase of 4-5 cm (the so-called period of the growth plateau), two periods are observed when the annual increment is much higher - The so-called. Periods spongy spurt (from English spurt - jerk). The first of them coincides with the nursery (youngest child) age - from birth to 3-4 years and is characterized by an initially sharp annual increase (up to 24 cm in the first year of life) with a gradual decrease in it by the time of transition to growth shgato. The duration of the second growth spurt is 2-4 years, its onset in girls prepubertal, and in boys - pubertal period, and the completion is accompanied by a slowdown, and then a complete cessation of spine growth by 16-19 years.

As for the average annual growth of the spine, this indicator is different in different age groups, both as a whole for the whole spine, and separately - in the thoracic and lumbar regions.

For a newborn child physiological is the sharp predominance of the size of the upper half of the body in comparison with the lower one. In the process of further natural development, the growth rates of the lower limbs exceed the growth rates of the spine, which is reflected in the dynamics of the growth factor - the ratio of growth of sitting / standing height.

Age indicators of the growth factor

Age	The value of the growth coefficient
1 year	0.63
2 years	0.60
16 years old (girls)	0.53
(boys)	0.52

Taking into account the termination of the child's growth by the age of 16-19 and the different rates of development of the trunk and lower limbs, JM Tanner and RH Whitehouse (1976) developed an index of growth of limbs and trunk length in norm, having calculated the ratio of the child's growth in different age periods to its predicted final growth. This indicator is of fundamental importance for assessing the degree of delay in the growth of the spine in its diseases or injuries in children.

The ratio of the child's growth in different age periods to its final growth (in percent)

Age (years)	Boys		Girls
	Height standing%	Sitting growth%	Height standing%	Sitting growth%
2 5 10 12 14 16	49 62 77 83 90 97	57 67 80 84 91 97	53 66 84 92 97	58 70 84 91 97

Concluding the description of anthropometric indices, characterizing the physiological growth of the spine, we consider it advisable to cite data on the average on-segment spine growth in norm.

Average annual segmental growth of the spine

Age	Average annual segmental growth of the spine
5-10 years Over 10 years old	0.05 cm 0,11cm

Formula RB Winter'a, logically derived from the table and allows you to predict the potential shortening of the spine when carrying out its bone-plastic fixation in different age periods. Although, we are well aware that this indicator can hardly be attributed to the "physiological parameters":

Potential shortening of the spine with spinal fusion = 0.07 cm × n1 × n2,

Where 0.07 is the average annual growth of the vertebrae, n1 is the number of blocked segments, n2 is the number of years remaining until the end of growth.

[7], [8], [9], [10], [11], [12]