Physiological curvature of the spine

Normal (or anatomical) posture is the ability of the trunk to maintain a vertical position in the sagittal and frontal planes with a uniform load on the legs, unbent in the knee joints. In a straight person with normal posture, the back of the shoulder, the angles of the shoulder blades, buttocks and heels should be in the same frontal plane, while the stomach should be pulled up. Normal posture of a person corresponds to the position of Forestier.

In the frontal plane with normal posture, the line of the spinous processes of the vertebrae projectively coincides with the conventional line of the plumb line, which runs from the occiput. At the same time, the levels of the shoulder, the angles of the shoulder blades, the bispinal and the bitrochannel lines are parallel, and the triangles of the waist are symmetrical. With normal anatomical posture, there is no curvature of the spine in the frontal plane.

In the sagittal plane with normal posture, the conventional plumb line, coinciding with the center of gravity, passes through the middle of the parietal region, the anterior edge of the external auditory canal, the C7 and T12 bodies of the vertebrae, the anterior part of the body of L5 and the middle of the foot. In the sagittal plane, the deviations of the spine from the plumb line in the thoracic and sacral parts of the posterior (kyphosis) are physiological, in the cervical and lumbar regions - anterior (lordosis).

The opinions of different authors on physiological curvatures in the sagittal plane coincide in that the vertex of the physiological kyphosis is at the level of the T7-T8 segments, with the kyphosis having a canopy formed by 8-10 vertebral segments (from T2-T3, T11-T12). Unity does not exist in the definition of the absolute value of physiological kyphosis, and the indicated values of its angle fluctuate in a fairly large range, from 15 ° to 50 °.

The physiological lumbar lordosis in adults is, according to WP Bunnell, from 40 ° to 60 °, and its apex is located at the level of L3-L4 vertebrae. Data on the absolute values of physiological lordosis in children and adolescents were not found.

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

Arrangement of the cone of the spinal cord

The level of the vertex of the cone of the spinal cord relative to the bodies of the lumbar vertebrae is an important anatomical indicator. As a result of the various rates of physiological development of the bone structures of the spine and the spinal cord contained in the vertebral canal, a gradual displacement of the cone of the spinal cord in the cranial direction occurs in the postnatal period. Thus, in a newborn, its apex is located at the level of the upper edge of L4 - the lower edge of the L3 vertebra. At the age of one month, the cone "rises" to the middle of the body L3, and by five years - to the lower edge of L2. Approximately to 8-10 years, the cone of the spinal cord occupies a position characteristic of adults, which corresponds to the mid-body L1 in women - the middle of the body of L2 vertebrae.

Using magnetic resonance imaging significantly improved the diagnosis of various pathological conditions of the spinal cord. The location of the cone of the spinal cord below the physiological level indicates its fixation that, in the presence of clinical manifestations of the syndrome of the stressed (fixed) cord syndrome, requires clarification of the cause of fixation (short terminal thread, tumor, malformation of the spinal cord , adhesive process, etc.) and appropriate neurosurgical correction.

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