X-ray anatomy of the spine normal

The structure of the spine is characterized by significant differences in different age periods. The concept of the norm is not static and implies the presence of age-specific features of the structure (structure) and shape of the individual vertebrae and vertebrae as a whole, the relationship between the sizes of vertebral bodies and discs, the specific values of the bone channels formed by the vertebrae, the boundaries of the functional mobility of the vertebral-motor segments, etc.

The shape and structure of the vertebrae in the age aspect in the radiographic image

Age	The form	Central slits of feeding vessels	Force lines of vertebrae
0-6 months.	Biconvex	Expressed	There are no (or slightly arched and radial lines).
6 months-2 yrs.	Biconvex	Expressed	Single at the end of the period.
2-4 yr	Start of flattening	More often expressed in the thoracic region, diverse in the depth of penetration into the body of the vertebrae.	Expressed longitudinal lines of force, there are power arcades in the arcs.
4-6 years old	Gradual transition to a rectangular form	Shallow, in the form of holes, cracks. Can be deep, sclerosed. Preservation of pronounced slits indicates dysplasia	Development of vertical and horizontal lines. The final construction of power arcades in the arcs.
Older than 6-7 years	Rectangular shape, the appearance of concavity of the centers of the epiphyseal plates, the anterior and posterior parts. The appearance of "steps" corresponding to the position of future apophyses	Also	Further strengthening of the lines of force.

In the process of growth in children, there is a uniform increase in the size of vertebral bodies and discs in the caudal direction, starting from T3. The growth varies from 1 to 2 mm, but is strictly individual. Violation of the uniform increase in the size of vertebrae and discs is usually observed in pathological conditions - vertebral dysplasia, trauma, tumors, inflammation, etc.

Another indicator that characterizes the correct development of the spine is the vertebral-discrete ratio-the ratio of the height of the vertebral body to the height of the contact disk. Its magnitude is normally between 5: 1 and 4: 1, and a decrease in the index is observed in systemic diseases that occur with spinal lesions - imperfect osteogenesis, dyshormonal spondylopathy, leukemia, etc.

The concept of the age norm includes the physiological terms of maturation of the vertebrae - the appearance of radiologically visible nuclei of ossification and the closure of interstitial growth zones. We do not accidentally talk about the timing of the radiographic closure of growth zones, because the analysis of the magnetic resonance tomograms of the spine allows us to state that the radiologically visible bone fusion is not always confirmed by MRI data. This is particularly evident when assessing the corporeal-dental synostosis of C2 and sacral and coccygeal vertebrae - even in adult patients, synchondrosis zones remain on MRI.

In 8-10% of people, the fusion of arcs L5 and S1 does not occur. If the absence of fusion of arcs is not accompanied by their dysplasia (hypoplasia, deformity, different angles of separation, etc.), then this is considered as a variant of the norm. In the presence of arterial dysplasia, one should speak of Spina bifida dysplastica.

Normal size of the spinal canal. The deviation of the size of the spinal canal from normal values is of fundamental importance. The widespread narrowing of the spinal canal is characteristic of some systemic skeletal diseases (for example, for achondroplasia), local - for congenital and acquired stenoses. An increase in the spinal canal is noted in dysplastic processes, malformations of the vertebral canal and spinal cord, long-term volumetric processes in the vertebral canal (see Elsberg-Dyke syndrome), and certain types of spine trauma.

Functional mobility of the vertebral-motor segments. Isolation of the functional motor unit of the vertebral column - the vertebral-motor segment (PD C), allows to estimate the volume of movements at the level of each segment. Movement in PDD C is due to arcuate joints and intervertebral discs. Obviously, movements in the PDS are different throughout the spine, not only in volume, but also occur in different planes. This is due to the peculiarities of the anatomical structure and spatial orientation of the intervertebral joints - the so-called. Tropism.

Skeletal maturity indicators

The clinical and radiological indices used to assess the maturity of the skeleton also reflect the degree of completeness of the spinal growth. Most often for the direct evaluation of the maturity of the spine, the definition of the degree of ossification of the apophyses of the vertebral bodies is used. Indirect maturity of the skeleton (and spine, among others) is determined by the apophysary test of Risser and the test of puberty Tanner. It should be noted that the last two tests have found the greatest application in practical vertebrology and are used to determine the likely progression of vertebral deformities in adolescents.

Degree of ossification of apophyses of vertebral bodies

The nuclei of ossification of apophyses of vertebral bodies in different parts of the spine appear not simultaneously. The earliest they appear in the vertebrae of the cervical and upper thoracic areas and then "spread" in the caudal direction. In different parts of the spine, age differences in the degree of maturation of the vertebrae can reach 4 years. To determine the bone age, they are guided by the latest stage of ossification, which is available for this child.

P. Stagnara (1974, 1982) distinguishes the following stages of the process of ossification of apophyses of vertebral bodies: 0 - absence of nuclei of ossification of terminal plates of vertebral bodies, 1 - appearance of point nuclei of ossification of apophyses, 2 - clearly visible triangular shadows of apophyses without fusion with vertebral bodies, initial signs of fusion of apophysises with vertebral bodies, 4 - almost complete fusion of apophyses with preservation of their traceable contour, 5 - complete fusion of apophysises.

A detailed description of the processes of ossification of the apophyses of vertebral bodies is also given by V.I. Sadofieva (1990):

Stage I - appearance of single point nuclei of ossification, II stage - multiple islet ossification nuclei, III stage - nuclei of ossification merge in the form of "bands", IV stage - initial signs of aduptial fusion (usually in the central divisions), stage V - complete fusion, however, the areas of enlightenment are seen, the sixth stage is the complete fusion (the completion of the maturation of the vertebra).

Apocryphal test of Risser (RisserJ-S, 1958). The indicator, called the "Risser test" and having the standard letter designation R, is determined by the prevalence of the apophysis ossification zone and its fusion with the wing of the ilium.

The test is used as one of the main signs for determining the potential for the progression of idiopathic spinal deformities in children and adolescents.

To determine the degree of the Risser test, the crest of the wing of the ilium is conventionally divided into 4 equal parts. The first foci of ossification of the crest of the ilium appear in its anterior regions and extend from the antero-superior to the posterior of the awn. The absence of zones of ossification of the apophyses is regarded as R0 and corresponds to a high potential for growth of the skeleton. The R1-R4 values correspond to the different phases of apophysis ossification, and R5 corresponds to the complete fusion of the ossified apophysis with the iliac wing and to stop the growth of the skeleton. The nucleus of ossification of the iliac crest at the anteroposterior level corresponding to the index R1 appears at the age of 10-11 years. Complete ossification of apophyses to stage R4 takes a period of 7 months. Up to 3.5 years, an average of 2 years. The closure of the apophysiological growth zone (R5) is observed on average between 13.3 to 14.3 years in girls and from 14.3 to 15.4 years in boys, but may occur at a later date, especially in children with delayed maturation of the skeleton (so called bone infantilism).

It should be remembered that the local bone age of the iliac bones does not always coincide with the bone age of the spine. Therefore, the Risser test is not absolutely accurate, but it is the most simple to determine and has a high degree of reliability in assessing the progression of scoliosis.

Tanner's test reflects the degree of puberty of adolescents includes the definition of severity of secondary sexual characteristics (T-system) and the pubic hair roller (P-system). The severity of the manifestations of the signs of the T and P systems has a certain parallelism, but there is no absolute coincidence of the stages.

Completion of puberty, corresponding to T5 and P5 stages, is associated with the completion of hormonal adjustment and is accompanied by a slowdown, and then a cessation of growth of the skeleton. That is why the Tanner test is used to predict the possible progression of idiopathic (dysplastic) deformities of the spine.

Another sign of puberty in adolescent girls is the time of the appearance of the first menstruation. In the individual developmental chart (patient history) of the patient, this indicator is fixed with the letter designation M (menarche) and the numerical designation of terms from menarche (year + month). It is found that more than 75% of the girls in menarche coincide with the indicator of the Risser test corresponding to R1, more than in 10% - with R2. The period of appearance of the first monthly is also used to predict the course of idiopathic deformities of the spine - their progression after the appearance of menstruation usually slows down, but it can still be observed during the next 1.5-2 years.

Different stages of sexual development of adolescents coincide with the period of the second growth spurt. In girls the onset of growth spurt precedes the onset of puberty, the spurt peak coincides with the TZ stage. The slowing down of growth spurt coincides with the appearance of menarche. In boys, the growth spurt begins after the appearance of the first signs of puberty, and the spurt peak coincides with the T4 stage.

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