Intervertebral disc - normal and pathological. How does lumbar spinal canal stenosis manifest? What is spinal canal stenosis

Based on the book:
Degenerative-dystrophic lesions of the spine (radiation diagnostics, complications after disectomy)

Rameshvili T.E. , Trufanov G.E., Gaidar B.V., Parfenov V.E.

Spinal column

The spinal column is normally a flexible formation, consisting in the average version of 33-34 vertebrae, connected into a single chain by intervertebral discs, facet joints and powerful ligaments.

The number of vertebrae in adults is not always the same: there are anomalies in the development of the spine associated with both an increase and a decrease in the number of vertebrae. Thus, the 25th vertebra of the embryo in an adult is assimilated by the sacrum, but in some cases it does not fuse with the sacrum, forming the 6th lumbar vertebra and 4 sacral vertebrae (lumbarization - likening the sacral vertebra to the lumbar).

There are also opposite relationships: the sacrum assimilates not only the 25th vertebra but also the 24th, forming 4 lumbar and 6 sacral vertebrae (sacralization). Assimilation can be complete, osseous, incomplete, bilateral or unilateral.

The following vertebrae are distinguished in the spinal column: cervical - 7, thoracic - 12, lumbar - 5, sacral - 5 and coccygeal - 4-5. Moreover, 9-10 of them (sacral - 5, coccygeal - 4-5) are connected motionlessly.

Normally, there is no curvature of the spinal column in the frontal plane. In the sagittal plane, the spinal column has 4 alternating smooth physiological curves in the form of arcs convexly directed anteriorly (cervical and lumbar lordosis) and arcs convexly directed posteriorly (thoracic and sacrococcygeal kyphosis).

The normal anatomical relationships in the spinal column are evidenced by the severity of physiological curves. The physiological curves of the spine are always smooth and are not normally angular, and the spinous processes are at the same distance from each other.

It should be emphasized that the degree of curvature of the spinal column in different parts is not the same and depends on age. Thus, at the time of birth, curves of the spinal column exist, but their severity increases as the child grows.

Vertebra

A vertebra (except for the two upper cervical ones) consists of a body, an arch and processes extending from it. The vertebral bodies are connected by intervertebral discs, and the arches are connected by intervertebral joints. The arches of adjacent vertebrae, joints, transverse and spinous processes are connected by a powerful ligamentous apparatus.

The anatomical complex, consisting of an intervertebral disc, two corresponding intervertebral joints and ligaments located at this level, represents a unique segment of spinal movements - the so-called. vertebral segment. The mobility of the spine in a single segment is small, but the movements of many segments provide the possibility of significant mobility of the spine as a whole.

The dimensions of the vertebral bodies increase in the caudal direction (from top to bottom), reaching a maximum in the lumbar region.

Normally, the vertebral bodies have the same height in the anterior and posterior sections.

An exception is the fifth lumbar vertebra, the body of which is wedge-shaped: in the ventral section it is higher than in the dorsal section (higher in the front than in the back). In adults, the body is rectangular with rounded corners. In the transitional thoracolumbar spine, a trapezoidal body of one or two vertebrae may be detected with a uniform bevel of the upper and lower surfaces anteriorly. The lumbar vertebra may have a trapezoidal shape with a posterior slope of the upper and lower surfaces. A similar shape to the fifth vertebra is sometimes mistaken for a compression fracture.

The vertebral body consists of spongy substance, the bone beams of which form a complex interweaving, the vast majority of them have a vertical direction and correspond to the main lines of load. The anterior, posterior and lateral surfaces of the body are covered with a thin layer of dense substance perforated by vascular canals.

An arch extends from the superolateral sections of the vertebral body, in which two sections are distinguished: the anterior, paired - pedicle and the posterior - plate ( Iamina), located between the articular and spinous processes. The following processes extend from the vertebral arch: paired - upper and lower articular (arcular) processes, transverse and single - spinous.

The described structure of the vertebra is schematic, since individual vertebrae not only in different sections, but also within the same section of the spinal column may have distinctive anatomical features.

A feature of the structure of the cervical spine is the presence of holes in the transverse processes of the C II - C VII vertebrae. These openings form a canal through which the vertebral artery passes with the sympathetic plexus of the same name. The medial wall of the canal is the middle part of the semilunar processes. This should be taken into account when the deformation of the semilunar processes increases and arthrosis of the uncovertebral joints occurs, which can lead to compression of the vertebral artery and irritation of the sympathetic plexuses.

Intervertebral joints

Intervertebral joints are formed by the lower articular processes of the overlying vertebra and the upper articular processes of the underlying vertebra.

The facet joints in all parts of the spinal column have a similar structure. However, the shape and location of their articular surfaces are not the same. Thus, in the cervical and thoracic vertebrae they are located in an oblique projection, close to the frontal, and in the lumbar vertebrae - to the sagittal. Moreover, if in the cervical and thoracic vertebrae the articular surfaces are flat, then in the lumbar vertebrae they are curved and look like segments of a cylinder.

Despite the fact that the articular processes and their articular surfaces in various parts of the spinal column have unique features, at all levels the articulating articular surfaces are equal to one another, lined with hyaline cartilage and reinforced by a tightly stretched capsule, attached directly to the edge of the articular surfaces. Functionally, all arcuate joints are classified as low-moving.

In addition to the facet joints, the true joints of the spine include:

paired atlanto-occipital joint connecting the occipital bone to the first cervical vertebra;
unpaired median atlanto-axial joint connecting vertebrae C I and C II;
paired sacroiliac joint connecting the sacrum to the iliac bones.

Intervertebral disc

The bodies of adjacent vertebrae from the second cervical to the first sacral are connected by intervertebral discs. The intervertebral disc is cartilaginous tissue and consists of the nucleus pulposus ( nucleus pulposus), annulus fibrosus ( Annulus fibrosis) and from two hyaline plates.

Nucleus pulposus- a spherical formation with an uneven surface, consists of a gelatinous mass with a high water content - up to 85-90% in the core, its diameter ranges from 1-2.5 cm.

In the intervertebral disc in the cervical region, the nucleus pulposus is displaced slightly anterior to the center, and in the thoracic and lumbar spine it is located on the border of the middle and posterior third of the intervertebral disc.

The nucleus pulposus is characterized by great elasticity and high turgor, which determines the height of the disc. The core is compressed in a disk under pressure of several atmospheres. The main function of the nucleus pulposus is a spring: acting like a buffer, it weakens and evenly distributes the influence of various shocks and shocks over the surfaces of the vertebral bodies.

Thanks to its turgor, the nucleus pulposus exerts constant pressure on the hyaline plates, pushing the vertebral bodies apart. The ligamentous apparatus of the spine and the fibrous ring of the discs counteract the nucleus pulposus, bringing adjacent vertebrae closer together. The height of each disc and the entire spinal column as a whole is not a constant value. It is associated with the dynamic balance of oppositely directed influences of the nucleus pulposus and the ligamentous apparatus and depends on the level of this balance, which corresponds primarily to the state of the nucleus pulposus.

The tissue of the nucleus pulposus is capable of releasing and binding water depending on the load, and therefore at different times of the day the height of a normal intervertebral disc is different.

Thus, in the morning, the height of the disc increases with the restoration of the maximum turgor of the nucleus pulposus and, to a certain extent, overcomes the elasticity of the traction of the ligamentous apparatus after an overnight rest. In the evening, especially after physical activity, the turgor of the nucleus pulposus decreases and adjacent vertebrae come closer together. Thus, a person’s height changes during the day depending on the height of the intervertebral disc.

In an adult, intervertebral discs make up approximately a quarter or even a third of the height of the spinal column. The noted physiological fluctuations in growth during the day can be from 2 to 4 cm. Due to the gradual decrease in turgor of the nucleus pulposus in old age, growth decreases.

The peculiar dynamic counteraction of the influences on the spinal column of the nucleus pulposus and the ligamentous apparatus is the key to understanding a number of degenerative-dystrophic lesions developing in the spine.

The nucleus pulposus is the center around which mutual movement of adjacent vertebrae occurs. When the spine flexes, the core moves posteriorly. When extending anteriorly and when bending sideways, move towards the convexity.

Fibrous ring, consisting of connective tissue fibers located around the nucleus pulposus, forms the anterior, posterior and lateral edges of the intervertebral disc. It is attached to the bony marginal edging through Sharpei fibers. The fibers of the annulus fibrosus are also attached to the posterior longitudinal ligament of the spine. The peripheral fibers of the fibrous ring make up a strong outer section of the disc, and the fibers closer to the center of the disc are looser, passing into the capsule of the nucleus pulposus. The anterior section of the fibrous ring is denser and more massive than the posterior one. The anterior part of the fibrous ring is 1.5-2 times larger than the posterior one. The main function of the annulus fibrosus is to fix adjacent vertebrae, hold the nucleus pulposus inside the disk, and ensure movement in different planes.

The cranial and caudal (upper and lower, respectively, in the standing position) surface of the intervertebral disc is formed by hyaline cartilaginous plates, inserted into the limbus (thickening) of the vertebral body. Each of the hyaline plates is equal in size and closely adjacent to the corresponding end plate of the vertebral body; it connects the nucleus pulposus of the disc to the bony end plate of the vertebral body. Degenerative changes in the intervertebral disc extend to the vertebral body through the endplate.

Ligamentous apparatus of the spinal column

The spinal column is equipped with a complex ligamentous apparatus, which includes: anterior longitudinal ligament, posterior longitudinal ligament, yellow ligaments, transverse ligaments, interspinous ligaments, supraspinous ligament, nuchal ligament and others.

Anterior longitudinal ligament covers the anterior and lateral surfaces of the vertebral bodies. It starts from the pharyngeal tubercle of the occipital bone and reaches the 1st sacral vertebra. The anterior longitudinal ligament consists of short and long fibers and bundles, which are firmly fused with the vertebral bodies and loosely connected with the intervertebral discs; above the latter, the ligament is thrown from one vertebral body to another. The anterior longitudinal ligament also serves as the periosteum of the vertebral bodies.

Posterior longitudinal ligament starts from the upper edge of the foramen magnum, lines the posterior surface of the vertebral bodies and reaches the lower part of the sacral canal. It is thicker, but narrower than the anterior longitudinal ligament and richer in elastic fibers. The posterior longitudinal ligament, unlike the anterior one, is firmly fused with the intervertebral discs and loosely fused with the vertebral bodies. Its diameter is not the same: at the level of the discs it is wide and completely covers the posterior surface of the disc, and at the level of the vertebral bodies it looks like a narrow ribbon. On the sides of the midline, the posterior longitudinal ligament passes into a thin membrane that separates the venous plexus of the vertebral bodies from the dura mater and protects the spinal cord from compression.

yellow ligaments consist of elastic fibers and connect the vertebral arches; they are especially clearly visualized on MRI in the lumbar spine, about 3 mm thick. The intertransverse, interspinous, and supraspinous ligaments connect the corresponding processes.

The height of the intervertebral discs gradually increases from the second cervical vertebra to the seventh, then a decrease in height is observed to Th IV and reaches a maximum at the level of the L IV -L V disc. The smallest heights are found in the uppermost cervical and upper thoracic intervertebral discs. The height of all intervertebral discs located caudal to the body of the Th IV vertebra increases evenly. The presacral disc is very variable both in height and shape; deviations in one direction or another in adults are up to 2 mm.

The height of the anterior and posterior sections of the disc in different parts of the spine is not the same and depends on the physiological bends. Thus, in the cervical and lumbar regions, the anterior part of the intervertebral discs is higher than the posterior one, and in the thoracic region the opposite relationships are observed: in the middle position, the disc has the shape of a wedge, with its apex facing backwards. With flexion, the height of the anterior part of the disc decreases and the wedge-shaped shape disappears, and with extension, the wedge-shaped shape is more pronounced. There is normally no displacement of the vertebral bodies during functional tests in adults.

Vertebral channel

The spinal canal is a container for the spinal cord, its roots and vessels; the spinal canal communicates cranially with the cranial cavity, and caudally with the sacral canal. For the exit of the spinal nerves from the spinal canal there are 23 pairs of intervertebral foramina. Some authors divide the spinal canal into a central part (dural canal) and two lateral parts (right and left lateral canals - intervertebral foramina).

In the side walls of the canal there are 23 pairs of intervertebral foramina, through which the roots of the spinal nerves and veins exit the spinal canal and the radicular-spinal arteries enter. The anterior wall of the lateral canal in the thoracic and lumbar regions is formed by the posterolateral surface of the bodies and intervertebral discs, and in the cervical region this wall also includes the uncovertebral joint; posterior wall - the anterior surface of the superior articular process and facet joint, yellow ligaments. The upper and lower walls are represented by cuttings of the legs of the arches. The upper and lower walls are formed by the inferior notch of the pedicle of the overlying vertebra and the superior notch of the pedicle of the underlying vertebra. The diameter of the lateral canal of the intervertebral foramina increases in the caudal direction. In the sacrum, the role of intervertebral foramina is played by four pairs of sacral foramina, which open on the pelvic surface of the sacrum.

The lateral (radicular) canal is limited externally by the pedicle of the overlying vertebra, in front by the vertebral body and intervertebral disc, and behind by the ventral sections of the intervertebral joint. The radicular canal is a semi-cylindrical groove about 2.5 cm long, running from the central canal from top to bottom and anteriorly. The normal anteroposterior size of the canal is at least 5 mm. There is a division of the root canal into zones: the “entry” of the root into the lateral canal, the “middle part” and the “exit zone” of the root from the intervertebral foramen.

The “3rd entrance” to the intervertebral foramen is the lateral recess. The reasons for root compression here are hypertrophy of the superior articular process of the underlying vertebra, congenital features of the development of the joint (shape, size), osteophytes. The serial number of the vertebra to which the superior articular process belongs in this type of compression corresponds to the number of the pinched spinal nerve root.

The “middle zone” is limited in front by the posterior surface of the vertebral body, in the back by the interarticular part of the vertebral arch, the medial sections of this zone are open towards the central canal. The main causes of stenosis in this area are osteophytes at the site of attachment of the ligamentum flavum, as well as spondylolysis with hypertrophy of the articular capsule of the joint.

In the “exit zone” of the spinal nerve root, the underlying intervertebral disc is located in front, and the outer parts of the joint are located behind. The causes of compression in this area are spondyloarthrosis and subluxations in the joints, osteophytes in the area of the upper edge of the intervertebral disc.

Spinal cord

The spinal cord begins at the level of the foramen magnum of the occipital bone and ends, according to most authors, at the level of the middle of the body of the L II vertebra (rarely occurring options are described at the level of L I and the middle of the body of the L III vertebra). Below this level is the terminal cistern containing the roots of the cauda equina (L II -L V, S I -S V and Co I), which are covered with the same membranes as the spinal cord.

In newborns, the end of the spinal cord is located lower than in adults, at the level of the L III vertebra. By 3 years of age, the conus spinal cord occupies its usual adult location.

The anterior and posterior roots of the spinal nerves arise from each segment of the spinal cord. The roots are directed to the corresponding intervertebral foramina. Here the dorsal root forms the spinal ganglion (local thickening - ganglion). The anterior and posterior roots join just after the ganglion to form the spinal nerve trunk. The upper pair of spinal nerves leaves the spinal canal at the level between the occipital bone and the C I vertebra, the lower pair – between the S I and S II vertebrae. There are a total of 31 pairs of spinal nerves.

Up to 3 months, the spinal cord roots are located opposite the corresponding vertebrae. Then the spine begins to grow more rapidly compared to the spinal cord. In accordance with this, the roots become longer towards the conus of the spinal cord and are located obliquely downwards towards their intervertebral foramina.

Due to the lag in the growth of the spinal cord in length from the spine, this discrepancy should be taken into account when determining the projection of the segments. In the cervical region, the spinal cord segments are located one vertebra higher than their corresponding vertebra.

There are 8 spinal cord segments in the cervical spine. Between the occipital bone and the C I vertebra there is a segment C 0 -C I where the C I nerve passes. Spinal nerves corresponding to the underlying vertebra emerge from the intervertebral foramen (for example, nerves C VI emerge from the intervertebral foramen C V -C V I).

There is a discrepancy between the thoracic spine and the spinal cord. The upper thoracic segments of the spinal cord are located two vertebrae higher than their corresponding vertebrae, and the lower thoracic segments are three. The lumbar segments correspond to Th X -Th XII vertebrae, and all sacral segments correspond to Th XII -L I vertebrae.

The continuation of the spinal cord from the level of the L I vertebra is the cauda equina. The spinal roots arise from the dural sac and diverge inferiorly and laterally to the intervertebral foramina. As a rule, they pass near the posterior surface of the intervertebral discs, with the exception of the L II and L III roots. The L II spinal root emerges from the dural sac above the intervertebral disc, and the L III root emerges below the disc. The roots at the level of the intervertebral discs correspond to the underlying vertebra (for example, the level of the disc L IV -L V corresponds to the L V root). The intervertebral foramen includes roots corresponding to the overlying vertebra (for example, L IV -L V corresponds to the L IV root).

It should be noted that there are several places where the roots can be affected in posterior and posterolateral herniated discs: the posterior intervertebral discs and the intervertebral foramen.

The spinal cord is covered by three meninges: dura ( dura mater spinalis), arachnoid ( arachnoidea) and soft ( pia mater spinalis). The arachnoid and pia mater, taken together, are also called the lepto-meningeal membrane.

Dura mater consists of two layers. At the level of the foramen magnum, the two layers completely separate. The outer layer is tightly adjacent to the bone and is, in fact, periosteum. The inner layer forms the dural sac of the spinal cord. The space between the layers is called the epidural ( cavitas epiduralis), epidural or extradural.

The epidural space contains loose connective tissue and venous plexuses. Both layers of the dura mater are connected together when the roots of the spinal nerves pass through the intervertebral foramen. The dural sac ends at the level of the S II -S III vertebrae. Its caudal part continues in the form of a terminal thread, which is attached to the periosteum of the coccyx.

The arachnoid mater consists of a cell membrane to which a network of trabeculae is attached. The arachnoid membrane is not fixed to the dura mater. The subarachnoid space is filled with circulating cerebrospinal fluid.

Pia mater lines all surfaces of the spinal cord and brain. The trabeculae of the arachnoid membrane are attached to the pia mater.

The upper border of the spinal cord is the line connecting the anterior and posterior segments of the arch of the C I vertebra. The spinal cord ends, as a rule, at the level L I -L II in the form of a cone, below which there is a cauda equina. The roots of the cauda equina emerge at an angle of 45° from the corresponding intervertebral foramen.

The dimensions of the spinal cord are not the same along its entire length; its thickness is greater in the area of the cervical and lumbar thickening. The sizes vary depending on the part of the spine:

at the level of the cervical spine - the anteroposterior size of the dural sac is 10-14 mm, the spinal cord is 7-11 mm, the transverse size of the spinal cord is close to 10-14 mm;
at the level of the thoracic spine - the anteroposterior size of the spinal cord corresponds to 6 mm, the dural sac - 9 mm, with the exception of the level of Th I - Th ll -vertebrae, where it is 10-11 mm;
in the lumbar spine - the sagittal size of the dural sac varies from 12 to 15 mm.

Epidural fat more developed in the thoracic and lumbar parts of the spinal canal.

P.S. Additional materials:

1. A 15-minute anatomical video atlas explaining the basics of the spine:

The spinal cord is a section of the central nervous system of the spine, which is a cord 45 cm long and 1 cm wide.

Structure of the spinal cord

The spinal cord is located in the spinal canal. Behind and in front there are two grooves, thanks to which the brain is divided into right and left halves. It is covered with three membranes: vascular, arachnoid and hard. The space between the choroid and arachnoid membranes is filled with cerebrospinal fluid.

In the center of the spinal cord you can see gray matter, shaped like a butterfly when cut through. Gray matter consists of motor and interneurons. The outer layer of the brain is white matter of axons collected in descending and ascending pathways.

There are two types of horns in the gray matter: anterior, which contains motor neurons, and posterior, where interneurons are located.

The structure of the spinal cord has 31 segments. From each of them extend the anterior and posterior roots, which, merging, form the spinal nerve. When they leave the brain, the nerves immediately split into roots - posterior and anterior. The dorsal roots are formed with the help of axons of afferent neurons and they are directed into the dorsal horns of the gray matter. At this point they form synapses with efferent neurons, whose axons form the anterior roots of the spinal nerves.

The dorsal roots contain the spinal nodes, which contain sensory nerve cells.

The spinal canal runs through the center of the spinal cord. To the muscles of the head, lungs, heart, thoracic organs and upper extremities, nerves arise from segments of the upper thoracic and cervical parts of the brain. The abdominal organs and trunk muscles are controlled by the lumbar and thoracic segments. The muscles of the lower abdominal cavity and the muscles of the lower extremities are controlled by the sacral and lower lumbar segments of the brain.

Functions of the spinal cord

There are two main functions of the spinal cord:

Conductor;
Reflex.

The conductor function is that nerve impulses move along the ascending pathways of the brain to the brain, and commands are sent through the descending pathways from the brain to the working organs.

The reflex function of the spinal cord is that it allows you to perform the simplest reflexes (knee reflex, withdrawal of the hand, flexion and extension of the upper and lower extremities, etc.).

Only simple motor reflexes are carried out under the control of the spinal cord. All other movements, such as walking, running, etc., require the participation of the brain.

Spinal cord pathologies

Based on the causes of spinal cord pathologies, three groups of spinal cord diseases can be distinguished:

Developmental defects – postnatal or congenital abnormalities in the structure of the brain;
Diseases caused by tumors, neuroinfections, spinal circulatory disorders, hereditary diseases of the nervous system;
Spinal cord injuries, which include bruises and fractures, compression, concussions, dislocations and hemorrhages. They can appear either independently or in combination with other factors.

Any disease of the spinal cord has very serious consequences. A special type of disease includes spinal cord injuries, which, according to statistics, can be divided into three groups:

Car accidents are the most common cause of spinal cord injury. Driving motorcycles is especially dangerous because there is no backrest to protect the spine.
A fall from a height can be either accidental or intentional. In any case, the risk of spinal cord damage is quite high. Often athletes, fans of extreme sports and jumping from heights get injured in this way.
Everyday and extraordinary injuries. They often occur as a result of going down and falling in the wrong place, falling down the stairs or when there is ice. This group also includes knife and bullet wounds and many other cases.

With spinal cord injuries, the conduction function is primarily disrupted, which leads to very disastrous consequences. For example, damage to the brain in the cervical region leads to the fact that brain functions are preserved, but they lose connections with most organs and muscles of the body, which leads to paralysis of the body. The same disorders occur when peripheral nerves are damaged. If the sensory nerves are damaged, sensation in certain areas of the body is impaired, and damage to the motor nerves impairs the movement of certain muscles.

Most nerves are of a mixed nature, and their damage causes both the inability to move and loss of sensation.

Spinal cord puncture

A spinal puncture involves inserting a special needle into the subarachnoid space. A puncture of the spinal cord is performed in special laboratories, where the patency of this organ is determined and the pressure of the cerebrospinal fluid is measured. The puncture is performed for both therapeutic and diagnostic purposes. It allows you to timely diagnose the presence of hemorrhage and its intensity, find inflammatory processes in the meninges, determine the nature of the stroke, and determine changes in the nature of the cerebrospinal fluid, signaling diseases of the central nervous system.

Often a puncture is performed to administer radiopaque and medicinal fluids.

For therapeutic purposes, a puncture is performed to extract blood or purulent fluid, as well as to administer antibiotics and antiseptics.

Indications for spinal cord puncture:

Meningoencephalitis;
Unexpected hemorrhages in the subarachnoid space due to rupture of an aneurysm;
Cysticercosis;
Myelitis;
Meningitis;
Neurosyphilis;
Traumatic brain injury;
Liquororrhea;
Echinococcosis.

Sometimes, during brain surgery, spinal cord puncture is used to reduce intracranial pressure parameters, as well as to facilitate access to malignant neoplasms.

The spinal cord (medulla spinalis) is a complex of gray matter nuclei and white nerve fibers, forming 31 pairs of segments. The spinal cord has a length of 43-45 cm, a mass of about 30-32 g. Each segment includes a part of the spinal cord, a corresponding sensory (sensitive) root entering from the dorsal side, and a motor (motor) root emerging from the ventral side of each segment.

The spinal cord is located in the spinal canal, surrounded by membranes between which cerebrospinal fluid circulates. In length, the spinal cord occupies the space between the first cervical and the upper edge of the second lumbar vertebra. In the lower part it has a medullary cone (conus medullaris), from which the terminal filament (filum terminale) begins, at the level of the II coccygeal vertebra, attached to the dura mater. The filament is part of the caudal section of the embryonic neural tube. When the spine flexes and extends, a slight displacement of the spinal cord occurs in the spinal canal. When a person is in an upright position during relative rest, the brain takes on the most stable position due to the elasticity of the spinal roots and mainly the dentate ligaments (ligg. dentata). Two pairs of dentate ligaments of each segment - derivatives of the pia mater - begin from the lateral surface of the spinal cord, between the anterior and posterior roots of the spinal nerves and are attached to the dura mater.

The diameter of the spinal cord along its length is uneven. At the level of the IV-VIII cervical and I thoracic segments, as well as in the lumbar and sacral regions, there are thickenings (intumescentiae cervicalis et lumbalis), which are caused by a quantitative increase in the nerve cells of the gray matter involved in the innervation of the upper and lower extremities.

458. External shape of the spinal cord.

A - spinal cord with spinal roots and sympathetic trunk (red); B - spinal cord from the ventral side; B - spinal cord from the dorsal side. 1 - fossa rhomboidea; 2 - intumescentia cervicalis; 3 - sulcus medianus posterior; 4 - sulcus lateralis posterior; 5 - fissura mediana anterior; 6 - sulcus lateralis anterior; 7 - intumescentia lumbalis; 8 - filum terminate.

The spinal cord consists of almost two symmetrical halves, separated in front by a deep median fissure (fissura mediana), and behind by a median groove (sulcus medianus) (Fig. 458). On the right and left halves there are anterior and posterior lateral grooves (sulci laterales anterior et posterior), in which the motor and sensory nerve roots are located, respectively. The spinal cord grooves delimit three cords of white matter located on the surface of the gray matter. They are formed by nerve fibers, which are grouped according to their functional properties, forming the so-called pathways (Fig. 459). The anterior cord (funiculus anterior) is located between the anterior fissure and the anterior lateral groove; the lateral cord (funiculus lateralis) is limited by the anterior and posterior lateral grooves; the posterior cord (funiculus posterior) is located between the posterior sulcus and the lateral posterior sulcus.

1 - posterior median groove and septum; 2 - thin fascicle (Gaull): 3 - wedge-shaped fascicle (Burdach): 4 - posterior sensory root; 5 - marginal zone: 6 - spongy layer; 7 - gelatinous substance; 8 - rear pillar; 9 - spinocerebellar posterior tract (Flexig); 10 - lateral cortical tract; 11 - reticular formation; 12 - own bundle of the spinal cord; 13-rednuclear-spinal tract; 14 - anterior spinocerebellar tract (Gowers); 15 - spinothalamic tract; 16- vestibulospinal tract; 17- anterior corticospinal tract; 18 - anterior median fissure; 19 - anterior median nucleus of the anterior column; 20 - anterior motor root; 21 - anterior lateral core of the anterior column; 22 - intermedial nucleus; 23 - intermediate-lateral nucleus of the lateral column; 24 - posterior lateral core of the anterior column; 25 - dorsal nucleus; 26 - own nucleus of the posterior horn.

In the cervical region and upper thoracic region, between the posterior median and posterior lateral grooves, there is a barely noticeable posterior intermediate groove (sulcus intermedius posterior), dividing the posterior cord into two bundles.

The gray matter of the spinal cord (substantia grisea medullae spinalis) occupies a central position in the spinal cord, appearing in a transverse section in the form of the letter “H”. It consists of multipolar nerve cells, myelinated, unmyelinated fibers and neuroglia.

Nerve cells form nuclei, which along the spinal cord merge into the anterior, lateral and posterior columns of gray matter (columnae anterior, lateralis et posterior). These columns * are connected in the middle by the anterior and posterior gray commissures (commisurae griseae anterior et posterior), separated by the central spinal canal, which represents a reduced canal of the embryonic neural tube.

Central canal of the spinal cord. The central canal represents a reduced remnant of the embryonic neural tube, which communicates at the top with the IV ventricle and ends with an expansion in the conus medullaris. Contains cerebrospinal fluid. It runs in the center of the spinal cord and has a diameter of 0.5×1 mm. In old age it may become partially obliterated.

Segments of the spinal cord. The spinal cord combines 31 pairs of segments: 8 cervical (C I-VIII), 12 thoracic (Th I-VII), 5 lumbar (L I-V), 5 sacral (S I-V) and 1 coccygeal (Co I). Each segment consists of a group of spinal ganglion cells that form the anterior and posterior columns, which connect with the fibers of the anterior and posterior roots of the spinal cord. The dorsal roots are formed by processes of sensory cells of the spinal ganglia, the anterior roots - by processes of motor cells of the nuclei of the anterior columns.

Spinal cord diameter

Based on the book:

Rameshvili T.E. , Trufanov G.E., Gaidar B.V., Parfenov V.E.

The spinal column is normally a flexible formation, consisting in the middle version of vertebrae connected into a single chain by intervertebral discs, facet joints and powerful ligaments.

A vertebra (except for the two upper cervical ones) consists of a body, an arch and processes extending from it. The vertebral bodies are connected by intervertebral discs, and the arches are connected by intervertebral joints. The arches of adjacent vertebrae, joints, transverse and spinous processes are connected by a powerful ligamentous apparatus.

The dimensions of the vertebral bodies increase in the caudal direction (from top to bottom), reaching a maximum in the lumbar region.

Normally, the vertebral bodies have the same height in the anterior and posterior sections.

An arch extends from the superolateral sections of the vertebral body, in which two sections are distinguished: the anterior, paired - pedicle and the posterior - plate (Iamina), located between the articular and spinous processes. The following processes extend from the vertebral arch: paired - upper and lower articular (arcicular) processes, transverse and single - spinous.

A feature of the structure of the cervical spine is the presence of holes in the transverse processes of the CII-CVI vertebrae. These openings form a canal through which the vertebral artery passes with the sympathetic plexus of the same name. The medial wall of the canal is the middle part of the semilunar processes. This should be taken into account when the deformation of the semilunar processes increases and arthrosis of the uncovertebral joints occurs, which can lead to compression of the vertebral artery and irritation of the sympathetic plexuses.

Intervertebral joints are formed by the lower articular processes of the overlying vertebra and the upper articular processes of the underlying vertebra.

In addition to the facet joints, the true joints of the spine include:

paired atlanto-occipital joint connecting the occipital bone to the first cervical vertebra;
unpaired median atlanto-axial joint connecting vertebrae CI and CII;
paired sacroiliac joint connecting the sacrum to the iliac bones.

The bodies of adjacent vertebrae from the second cervical to the first sacral are connected by intervertebral discs. The intervertebral disc is cartilaginous tissue and consists of a pulpous nucleus (nucleus pulposus), a fibrous ring (annulus fibrosis) and two hyaline plates.

The nucleus pulposus is a spherical formation with an uneven surface, consists of a gelatinous mass with a high water content - up to 85-90% in the nucleus, its diameter ranges from 1-2.5 cm.

The fibrous ring, consisting of connective tissue fibers located around the nucleus pulposus, forms the anterior, posterior and lateral edges of the intervertebral disc. It is attached to the bony marginal edging through Sharpei fibers. The fibers of the annulus fibrosus are also attached to the posterior longitudinal ligament of the spine. The peripheral fibers of the fibrous ring make up a strong outer section of the disc, and the fibers closer to the center of the disc are looser, passing into the capsule of the nucleus pulposus. The anterior section of the fibrous ring is denser and more massive than the posterior one. The anterior part of the fibrous ring is 1.5-2 times larger than the posterior one. The main function of the fibrous ring is to fix adjacent vertebrae, hold the nucleus pulposus inside the disc, and ensure movement in different planes.

The cranial and caudal (upper and lower, respectively, in a standing position) surface of the intervertebral disc is formed by hyaline cartilaginous plates inserted into the limbus (thickening) of the vertebral body. Each of the hyaline plates is equal in size and closely adjacent to the corresponding end plate of the vertebral body; it connects the nucleus pulposus of the disc to the bony end plate of the vertebral body. Degenerative changes in the intervertebral disc extend to the vertebral body through the endplate.

Ligamentous apparatus of the spinal column

The anterior longitudinal ligament covers the anterior and lateral surfaces of the vertebral bodies. It starts from the pharyngeal tubercle of the occipital bone and reaches the 1st sacral vertebra. The anterior longitudinal ligament consists of short and long fibers and bundles, which are firmly fused with the vertebral bodies and loosely connected with the intervertebral discs; above the latter, the ligament is thrown from one vertebral body to another. The anterior longitudinal ligament also serves as the periosteum of the vertebral bodies.

The posterior longitudinal ligament begins from the upper edge of the foramen magnum, lines the posterior surface of the vertebral bodies and reaches the lower part of the sacral canal. It is thicker, but narrower than the anterior longitudinal ligament and richer in elastic fibers. The posterior longitudinal ligament, unlike the anterior one, is firmly fused with the intervertebral discs and loosely fused with the vertebral bodies. Its diameter is not the same: at the level of the discs it is wide and completely covers the posterior surface of the disc, and at the level of the vertebral bodies it looks like a narrow ribbon. On the sides of the midline, the posterior longitudinal ligament passes into a thin membrane that separates the venous plexus of the vertebral bodies from the dura mater and protects the spinal cord from compression.

The ligamentum flavum consists of elastic fibers and connects the vertebral arches; they are especially clearly visualized on MRI in the lumbar spine, about 3 mm thick. The intertransverse, interspinous, and supraspinous ligaments connect the corresponding processes.

The height of the intervertebral discs gradually increases from the second cervical vertebra to the seventh, then a decrease in height is observed to ThIV and reaches a maximum at the level of the LIV-LV disc. The smallest heights are found in the uppermost cervical and upper thoracic intervertebral discs. The height of all intervertebral discs located caudal to the ThIV vertebral body increases uniformly. The presacral disc is very variable both in height and shape; deviations in one direction or another in adults are up to 2 mm.

In the side walls of the canal there are 23 pairs of intervertebral foramina, through which the roots of the spinal nerves and veins exit the spinal canal and the radicular-spinal arteries enter. The anterior wall of the lateral canal in the thoracic and lumbar regions is formed by the posterolateral surface of the bodies and intervertebral discs, and in the cervical region this wall also includes the uncovertebral joint; posterior wall – the anterior surface of the superior articular process and facet joint, yellow ligaments. The upper and lower walls are represented by cuttings of the legs of the arches. The upper and lower walls are formed by the inferior notch of the pedicle of the overlying vertebra and the superior notch of the pedicle of the underlying vertebra. The diameter of the lateral canal of the intervertebral foramina increases in the caudal direction. In the sacrum, the role of intervertebral foramina is played by four pairs of sacral foramina, which open on the pelvic surface of the sacrum.

The lateral (radicular) canal is limited externally by the pedicle of the overlying vertebra, in front by the vertebral body and intervertebral disc, and behind by the ventral sections of the intervertebral joint. The radicular canal is a semi-cylindrical groove about 2.5 cm long, running from the central canal from top to bottom and anteriorly. The normal anteroposterior canal size is at least 5 mm. There is a division of the root canal into zones: the “entry” of the root into the lateral canal, the “middle part” and the “exit zone” of the root from the intervertebral foramen.

In the “exit zone” of the spinal nerve root, the underlying intervertebral disc is located in front, and the outer parts of the joint are behind. The causes of compression in this area are spondyloarthrosis and subluxations in the joints, osteophytes in the area of the upper edge of the intervertebral disc.

The spinal cord begins at the level of the foramen magnum of the occipital bone and ends, according to most authors, at the level of the middle of the body of the LII vertebra (rarely occurring variants are described at the level of LI and the middle of the body of the LIII vertebra). Below this level is the terminal cistern containing the roots of the cauda equina (LII-LV, SI-SV and CoI), which are covered by the same membranes as the spinal cord.

In newborns, the end of the spinal cord is located lower than in adults, at the level of the LIII vertebra. By 3 years of age, the conus spinal cord occupies its usual adult location.

The anterior and posterior roots of the spinal nerves arise from each segment of the spinal cord. The roots are directed to the corresponding intervertebral foramina. Here the dorsal root forms the spinal ganglion (local thickening - ganglion). The anterior and posterior roots join just after the ganglion to form the spinal nerve trunk. The upper pair of spinal nerves leaves the spinal canal at the level between the occipital bone and the CI vertebra, the lower pair - between the SI and SII vertebrae. There are a total of 31 pairs of spinal nerves.

There are 8 spinal cord segments in the cervical spine. Between the occipital bone and the CI vertebra there is a segment C0-CI where the CI nerve passes. The spinal nerves corresponding to the underlying vertebra emerge from the intervertebral foramen (for example, the CVI nerves emerge from the intervertebral foramen CV-CVI).

There is a discrepancy between the thoracic spine and the spinal cord. The upper thoracic segments of the spinal cord are located two vertebrae higher than their corresponding vertebrae, and the lower thoracic segments are three. The lumbar segments correspond to the ThX-ThXII vertebrae, and all sacral segments correspond to the ThXII-LI vertebrae.

The continuation of the spinal cord from the level of the LI-vertebra is the cauda equina. The spinal roots arise from the dural sac and diverge inferiorly and laterally to the intervertebral foramina. As a rule, they pass near the posterior surface of the intervertebral discs, with the exception of the roots LII and LIII. The spinal root LII emerges from the dural sac above the intervertebral disc, and the spinal root LIII exits below the disc. The roots at the level of the intervertebral discs correspond to the underlying vertebra (for example, the level of the LIV-LV disc corresponds to the LV root). The intervertebral foramen includes roots corresponding to the overlying vertebra (for example, LIV-LV corresponds to the LIV root).

It should be noted that there are several places where the roots can be affected in posterior and posterolateral herniated discs: the posterior intervertebral discs and the intervertebral foramen.

The spinal cord is covered by three meninges: dura mater spinalis, arachnoid (arachnoidea) and pia mater spinalis. The arachnoid and pia mater, taken together, are also called the lepto-meningeal membrane.

The dura mater consists of two layers. At the level of the foramen magnum, the two layers completely separate. The outer layer is tightly adjacent to the bone and is, in fact, periosteum. The inner layer forms the dural sac of the spinal cord. The space between the layers is called epidural (cavitas epiduralis), peridural or extradural.

The epidural space contains loose connective tissue and venous plexuses. Both layers of the dura mater are connected together when the roots of the spinal nerves pass through the intervertebral foramen. The dural sac ends at the level of the SII-SIII vertebrae. Its caudal part continues in the form of a terminal thread, which is attached to the periosteum of the coccyx.

The pia mater lines all surfaces of the spinal cord and brain. The trabeculae of the arachnoid membrane are attached to the pia mater.

The upper border of the spinal cord is the line connecting the anterior and posterior segments of the CI vertebral arch. The spinal cord ends, as a rule, at the level LI-LII in the form of a cone, below which there is a cauda equina. The roots of the cauda equina emerge at an angle of 45° from the corresponding intervertebral foramen.

at the level of the cervical spine - the anteroposterior size of the dural sac is mm, the spinal cord is 7-11 mm, the transverse size of the spinal cord approaches kmm;
at the level of the thoracic spine - the anteroposterior size of the spinal cord corresponds to 6 mm, the dural sac - 9 mm, with the exception of the level of the ThI-Thll vertebrae, where it is mm;
in the lumbar spine - the sagittal size of the dural sac varies from 12 to 15 mm.

Epidural fatty tissue is more developed in the thoracic and lumbar parts of the spinal canal.

The structure of the human spinal cord and its functions

The spinal cord, along with the brain, is an integral part of the central nervous system. It is difficult to overestimate the work of this organ in the human body. After all, with any defects, it becomes impossible for the body to fully communicate with the outside world. It is not for nothing that congenital defects, which can be detected using ultrasound diagnostics already in the first trimester of pregnancy, are most often an indication for termination of pregnancy. The importance of the functions of the spinal cord in the human body determines the complexity and uniqueness of its structure.

Anatomy

Location

It is localized in the spinal canal, being a direct continuation of the medulla oblongata. Conventionally, the upper anatomical border of the spinal cord is considered to be the line connecting the upper edge of the first cervical vertebra with the lower edge of the foramen magnum.

The spinal cord ends approximately at the level of the first two lumbar vertebrae, where it gradually narrows: first to the conus medullaris, then to the medullary or filum terminale, which, passing through the canal of the sacral spine, is attached to its end.

This fact is important in clinical practice, since when performing the well-known epidural anesthesia at the lumbar level, the spinal cord is absolutely out of danger from mechanical damage.

Watch a useful video that shows the structure and location of the spinal cord in an interesting and accessible way.

Spinal membranes

Hard - on the outer side it includes the tissues of the periosteum of the spinal canal, followed by the epidural space and the inner layer of the hard shell.
Arachnoid - a thin, colorless plate fused with the hard shell in the area of the intervertebral foramina. Where there are no adhesions, there is a subdural space.
Soft or vascular - separated from the previous membrane by the subarachnoid space with cerebrospinal fluid. The soft shell itself is adjacent to the spinal cord and consists mostly of vessels.

The entire organ is completely immersed in the cerebrospinal fluid of the subarachnoid space and “floats” in it. Its fixed position is given by special ligaments (dentate and intermediate cervical septum), with the help of which the inner part is attached to the shells.

External characteristics

The shape of the spinal cord is a long cylinder, slightly flattened from front to back.
Average length approx. cm, depending

from human growth.

Weight is about one time less than the weight of the brain,

Repeating the contours of the spine, the spinal structures have the same physiological curves. At the level of the neck and the lower part of the thoracic, beginning of the lumbar regions, two thickenings are distinguished - these are the exit points of the roots of the spinal nerves, which are responsible for the innervation of the arms and legs, respectively.

There are 2 grooves running along the back and front of the spinal cord, which divide it into two absolutely symmetrical halves. Along the entire length of the organ there is a hole in the middle - the central canal, which connects at the top with one of the ventricles of the brain. Below, towards the area of the conus medullaris, the central canal expands, forming the so-called terminal ventricle.

Internal structure

It consists of neurons (nervous tissue cells), the bodies of which, concentrated in the center, form the spinal gray matter. According to scientists, there are only about 13 million neurons in the spinal cord - thousands of times less than in the brain. The location of the gray matter inside the white matter is somewhat different in shape, which in cross section vaguely resembles a butterfly.

The front horns are rounded and wide. Consist of motor neurons that transmit impulses to the muscles. This is where the anterior roots of the spinal nerves—the motor roots—begin.
The posterior horns are long, narrow, and consist of intermediate neurons. They receive signals from the sensory roots of the spinal nerves - the dorsal roots. There are also neurons here that, through nerve fibers, interconnect different parts of the spinal cord.
Lateral horns - found only in the lower segments of the spinal cord. They contain so-called vegetative nuclei (for example, centers for pupil dilation, innervation of sweat glands).

The gray matter is surrounded on the outer side by white matter - these are essentially processes of neurons from the gray matter or nerve fibers. The diameter of the nerve fibers is no more than 0.1 mm, but their length sometimes reaches one and a half meters.

The functional purpose of nerve fibers can be different:

ensuring the interconnection of different levels of the spinal cord;
transmission of data from the brain to the spinal cord;
ensuring the delivery of information from the spinal to the head.

Nerve fibers, integrated into bundles, are located in the form of spinal cords along the entire length of the spinal cord.

A modern effective method of treating back pain is pharmacopuncture. Minimum doses of drugs injected into active points work better than tablets and regular injections: http://pomogispine.com/lechenie/farmakopunktura.html.

What is better for diagnosing spinal pathologies: MRI or computed tomography? We tell here.

Spinal nerves

The spinal nerve by its nature is neither sensory nor motor - it contains nerve fibers of both types, since it combines the anterior (motor) and posterior (sensitive) roots.

It is these mixed spinal nerves that exit in pairs through the intervertebral foramina

on the left and right sides of the spine.

In total, a pair of them, of which:

The area of the spinal cord that is the “launching pad” for one pair of nerves is called a segment or neuromere. Accordingly, the spinal cord consists of only

from segments.

It is interesting and important to know that the spinal segment is not always located in the part of the spine with the same name due to the difference in the length of the spine and the spinal cord. But the spinal roots still emerge from the corresponding intervertebral foramina.

For example, the lumbar spinal segment is located in the thoracic spinal column, and its corresponding spinal nerves emerge from the intervertebral foramina in the lumbar spine.

Functions of the spinal cord

Now let’s talk about the physiology of the spinal cord, about what “responsibilities” are assigned to it.

The spinal cord contains segmental or working nerve centers that are directly connected to and control the human body. It is through these spinal working centers that the human body is subject to control by the brain.

In this case, certain spinal segments control clearly defined parts of the body by receiving nerve impulses from them along sensory fibers and transmitting response impulses to them along motor fibers:

The spinal cord carries out some autonomic or complex motor reflexes without brain intervention at all, thanks to the two-way connection it has with all parts of the human body - this is how the spinal cord performs its reflex functions. For example, the reflex centers for urination or erection are located in 3-5 sacral segments, and with spinal damage in this place, these reflexes may be lost.

The conductive spinal function is ensured by the fact that all the conductive pathways connecting parts of the nervous system with each other are localized in the white matter. Along the ascending pathways, information from tactile, temperature, pain receptors and movement receptors from the muscles (proprioceptors) is transmitted first to the spinal cord, and then to the corresponding parts of the brain. Descending pathways connect the brain and spinal cord in reverse order: with their help, the brain controls the activity of human muscles.

Risk of damage and injury

Any spinal cord injury threatens a person's life.

Serious damage to other spinal segments located below may not cause death, but will lead to partial or complete disability in almost 100% of cases. Therefore, nature intended that the spinal cord be under reliable protection of the spine.

The expression “healthy spine” in most cases is equivalent to the expression “healthy spinal cord”, which is one of the necessary conditions for a high-quality, full-fledged human life.

We offer another interesting video that will help you understand the anatomy of the spinal structures and their functioning.

There is only one reason - the spine.

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Introduction

The average diameter of the spinal canal in the cervical spine ranges from 14 to 25 mm J.G. Arnold (1955), the size of the spinal cord ranges from 8 to 13 mm, and the thickness of the soft tissues (shell and ligaments) ranges from 2 to 3 mm. Thus, the average reserve space in the ventrodorsal direction, in the cervical spine, is approximately 3 mm. Considering the above, we can conclude that a decrease in the diameter of the spinal canal by 3 mm leads to compression of the spinal cord; accordingly, this condition is regarded as spinal canal stenosis. With more than 30% narrowing of the diameter of the spinal canal, cervical myelopathy develops. At the same time, in some patients with significant narrowing of the spinal canal, myelopathy is not observed. The diagnosis of cervical spinal canal stenosis is made when the anteroposterior size of the latter decreases to 12 mm or less. A narrowing of the spinal canal to 12 mm is considered relative stenosis, while a decrease in this size to 10 mm is absolute stenosis. In turn, the average size of the spinal canal in patients with cervical myelopathy is 11.8 mm. Patients with a spinal canal diameter of 14mm are at risk. When the size of the spinal canal decreases to 10 mm, myelopathy is inevitable. Myelopathy rarely develops in patients with a spinal canal diameter of 16 mm. Clinical picture of cervical myelopathy

Table 1

cervical myelopathy
Myelopathy and radiculopathy
hyperreflexia
Babinski reflex
Hofmann reflex
Conductive sensory disturbances
Radicular sensory disturbances
Disturbances of deep feeling
Instability in the Romberg position
Monoparesis of the arm
Paraparesis
Hemiparesis
Tetraparesis
Brown-Séquard syndrome
Muscle atrophy
Fascicular twitching
Radicular pain in the arms
Radicular pain in the legs
Cervicalgia
Muscle spasticity
Disorders of the pelvic organs

is very diverse and is represented in a late stage by syndromes reminiscent of many neurological diseases: multiple sclerosis, spinal cord tumors, spinocerebellar degenerations. In 50 percent of patients with severe clinical manifestations of spinal stenosis, there is usually a constant progression of symptoms. Conservative treatment, according to a number of authors, is little or not at all effective for this disease. The frequency of various symptoms with cervical spinal stenosis is given in Table. 1.

All this variety of symptoms develops into 5 main clinical syndromes for cervical spinal stenosis - transverse spinal cord syndrome, pyramidal syndrome with predominant damage to the main corticospinal tract, centromedullary syndrome with motor and sensory disturbances in the upper extremities, Brown-Séquard syndrome (damage to half the diameter spinal cord) and cervical dyscalgia.

The goal of surgical treatment for spinal stenosis is to eliminate compression of the spinal cord and the roots of their vessels. Positive results of surgical treatment, according to various authors, range from 57-96 percent, but some authors believe that surgery for spinal stenosis, at best, stops the progression of neurological deficit, but does not lead to complete recovery. The results of surgical treatment for absolute stenosis of the cervical spine are even more inconclusive.

Purpose of the study

Determination of the feasibility of surgical treatment of absolute stenosis of the cervical spinal canal.

Material and methods

In the Department of Neurosurgery of the Mikaelyan Institute of Surgery from 2001-2011. 33 patients (29 men, 4 women) aged from 34 to 71 years were operated on, with a diagnosis of cervical spinal canal stenosis and cervical myelopathy. The diagnosis was made on the basis of complaints, anamnesis, clinical picture, MRI examination of the cervical spine, ENMG. According to the neurological picture, they are divided into 3 groups (Table 2).

table 2

The anteroposterior size of the spinal canal ranged from 4 to 8 mm (Table 3), and the extent of compression ranged from one level to three (Table 4).

Table 3

Channel size s\m	3 mm	4 mm	5 mm	6 mm	7 mm	12 mm
Number of patients

Table 4

Decompression of the spinal cord was performed using an anterior or posterior approach, depending on the compressive agent. Anterior decompression - discectomy according to Cloward followed by spinal fusion with an autograft and fixation with a metal plate was performed if the compressive agent was the anterior wall of the spinal canal, namely a herniated intervertebral disc and ossified posterior longitudinal ligament; posterior decompression - laminectomy at stenotic levels was performed if there was hypertrophied vertebral arches and ossified ligamentum flavum - the posterior wall of the spinal canal.

Research results

The result was assessed as follows. Excellent - no neurological deficits or minimal sensory impairment. Good - an increase in muscle strength by 1-2 points, minimal sensory disturbances, while the muscle strength of the limbs after treatment should be at least 4 points. Satisfactory - increase in muscle strength by 1 point, sensory disorders, neuropathic pain in the extremities. Unsatisfactory - lack of effect from surgical treatment, dysfunction of the pelvic organs (acute urinary retention, constipation). Bad - worsening neurological deficit, respiratory failure, death. An excellent result was obtained in 1 patient, good in 12, satisfactory in 13, unsatisfactory in 6 and poor in 1 patient (Table 5).

Table 5

Size sp\k. mm	1 bad	2 bad	3 beats	4 chorus	5 ex.

Discussion of results and conclusions

In group 1 with a poor result, we had one death due to ascending edema of the spinal cord and trunk. This patient had spinal canal stenosis at the level of C3 up to 3 mm due to the discosteophyte complex; anterior decompression was performed - discectomy, followed by spinal fusion with an autograft and fixation with a metal plate. In group 2 with an unsatisfactory result, we have 6 patients with a spinal canal size of less than 5 mm, in 2 of them the spinal canal was stenotic due to a discosteophytic complex at two levels; they underwent discectomy followed by spinal fusion with an autograft at two levels.

Thus, the risk factor for surgical treatment of spinal canal stenosis is the upper cervical region and narrowing of the spinal canal to 3 mm. An unsatisfactory result can be expected with a narrowing of the spinal canal to 5 mm, as well as multi-level narrowing of the spinal canal due to the anterior wall - herniated intervertebral discs and ossified posterior longitudinal ligament.

Bibliography

Livshits A.V. Spinal cord surgery. Moscow, “Medicine”, 1990. pp. 179-190.
Adams CBT, Logue V: Studies in Cervical Spondylotic Myelopathy: II. The Movement and Contour of the Spine in Relation to the Neural Complications of Cervical Spondylosis. Brain 94:569-86, 1971.
Cooper PR: Cervical Spondylotic Myelopathy. Contemp Neurosurg 19(25): 1-7, 1997.
Crandall PH, Batrdorf U: Cervical Spondylotic Myelopathy. J Neurosurg 25:57-66, 1966.
Epstein JA, Marc JA. Total Myelography in the Evaluation of Lumbar Disks Spine 4: 121-8, 1979.
England JD, Hsu CY, Vera CL. Spondylotic High Cervical Spinal Cord Compression Presenting with Hand Complaints. Surg Neurol 25: 299-303 1986.
Houser OW, Onofrio BM, Miller GM. Cervical Spondylotic Stenosis and Myelopathy: Evaluation with Computed Tomographis Myelography. Mayo Clin Proc 557-63, 1994.
Johnsson K., Posen I., Uden A. Acta Orthopedic Scand, 1993, Vol.64, P67-6.
Krauss WE, Ebersold MJ, Quast LM: Cervical Spondylotic Myelopathy: Surgical Indications and Technique. Contemp Neurosurg 20(10): 1-6, 1998.
Lunstord LD, Bissonette DJ, Zorub DS: Anterior Surgery for Cervical Disc Disease. Part 2: Treatment of Cervical Spondylotis Myelopathy in 32 Cases J Neurosurg 53: 12-9,1980.
Turner J., Ersek M., Herron L.// Ibid, 1992, Vol/17, P1-8.
Vockuhi RR, Hinton RC: Sensory Impairment in the Hands Secondary to Spondylotic Compression of the Cervical Spinal Cord Arch Neurol 47: 309-11, 1990.
Wolf BS, Khilnani M, Malis L: The Sagittal Diameter of the Bony Cervical Spinal Canal and its Significance in Cervical Spondylosis. J of Mount Sinai Hospital 23: 283-92, 1956.
Yu Y L, du Boulay G H, Stevens J M. Coputed Tomografi in Cervical Spondylotic Myelopathy and Radiculopathy. Neuroradiology 28: 221-36, 1986.

The spinal cord is a cord of nerve tissue located inside the bony canal of the spine. In an adult, its length is 41−45 cm, and its diameter is 1−1.5 cm. The spinal cord and brain are the central links of the nervous system.

At the top, the spinal cord merges with the medulla oblongata. Its lower extremity at the 2nd lumbar vertebra becomes thinner, turning into a medullary cone. Next, the rudimentary spinal cord in the form of a terminal filament penetrates the sacral canal, attaching to the periosteum of the coccyx. At the points where the spinal nerves exit to the upper and lower extremities, cervical and lumbar thickenings of the brain are formed.
The anterior concave surface of the medullary cord along its length forms the anterior median fissure. Posteriorly, the surface of the brain is divided by a narrow median sulcus. These lines divide it into symmetrical halves. The motor anterior and sensory posterior nerve roots emerge along the lateral surfaces of the brain. The posterior nerve roots consist of processes of sensory neuron cells. They enter the brain along the posterolateral sulcus. The anterior roots are formed by the axons of motor cells - motor neurons. The processes emerge from the brain substance in the anterolateral sulcus. Before leaving the spinal canal, the sensory and motor nerve roots unite, forming symmetrical pairs of mixed spinal nerves. These nerves, leaving the bone canal between 2 adjacent vertebrae, are directed to the periphery. The length of the bony canal of the spine exceeds the length of the medullary cord. The reason for this is the high rate of bone growth compared to nerve tissue. Therefore, in the lower parts of the spine, the nerve roots are located vertically.

The anterior and posterior spinal arteries, as well as the spinal branches of the segmental branches of the descending aorta - the lumbar and intercostal arteries, supply blood to the structures of the spinal cord and spine.
In the section, you can discern the internal structure of the brain tissue. In the center, shaped like a butterfly or a capital H, there is gray matter surrounded by white matter. Along the entire length of the nerve cord there is a central canal containing cerebrospinal fluid. The lateral projections of the gray matter form gray pillars. In section, the pillars are visible as the posterior horns, formed by the bodies of sensory neurons, and the anterior horns, consisting of the bodies of motor cells. The halves of the “butterfly” are connected by a bridge made of a central intermediate substance. The area of the brain with a pair of roots is called the spinal segment. Humans have 31 spinal segments. The segments are grouped by location: 8 are in the cervical region, 12 in the thoracic region, 5 in the lumbar region, 5 in the sacral region, 1 in the coccygeal region.

The white matter of the brain is composed of processes of nerve cells - sensory dendrites and motor axons. Surrounding the gray matter, it also consists of 2 halves, connected by a thin white commissure - the commissure. The cell bodies of neurons themselves can be located in any part of the nervous system.

Bundles of nerve cell processes carrying signals in one direction ( only to centers or only from centers) are called pathways. The white matter in the spinal cord is combined into 3 pairs of cords: anterior, posterior, lateral. The anterior cords are limited by the anterior pillars. The lateral funiculi are delimited by the posterior and anterior pillars. The lateral and anterior cords carry conductors of 2 types. Ascending pathways carry signals to the CNS - the central parts of the nervous system. And the descending paths go from the nuclei of the central nervous system to the motor neurons of the anterior horns. The posterior cords run between the posterior columns. They represent ascending pathways that carry signals to the brain - the cerebral cortex. This information forms the joint-muscular feeling - an assessment of the location of the body in space.

Embryonic development

The nervous system is laid in the embryo at the age of 2.5 weeks. On the dorsal side of the body, a longitudinal thickening of the ectoderm is formed - the neural plate. Then the plate bends along the midline and becomes a groove limited by the neural folds. The groove closes into the neural tube, separating itself from the skin ectoderm. The anterior end of the neural tube thickens, becoming the brain. The spinal cord develops from the rest of the tube.

The length of the spinal cord of newborns in relation to the size of the spinal canal is greater than that of an adult. In children, the spinal cord reaches the 3rd lumbar vertebra. Gradually, the growth of the nervous tissue lags behind the growth of the bone tissue of the spine. The lower end of the brain moves upward. At the age of 5–6 years, the ratio of the length of the spinal cord to the size of the spinal canal in a child becomes the same as in an adult.

In addition to conducting nerve impulses, the purpose of the spinal cord is the closure of unconditioned motor reflexes at the level of the spinal segments.

Diagnostics

The spinal reflex is the contraction of a muscle in response to a stretch in its tendon. The severity of the reflex is checked by tapping the muscle tendon with a neurological hammer. According to the state of individual reflexes, the location of the lesion in the spinal cord is specified. When a segment of the spinal cord is damaged, there is a violation of deep and superficial sensitivity in the corresponding areas of the body - dermatomes. Spinal vegetative reflexes also change - visceral, vascular, urinary.

The movements of the limbs, their muscle tone, and the severity of deep reflexes characterize the work of the descending conductors in the anterior and lateral cords of the brain. Determining the area of disturbance of tactile, temperature, pain and joint-muscular sensitivity helps to find the level of damage to the posterior and lateral cords.

To clarify the localization of the lesion in the brain, determine the nature of the disease ( inflammation, hemorrhage, tumor) additional research is needed. A spinal tap will help assess cerebrospinal fluid pressure and the condition of the meninges. The resulting liquor is examined in the laboratory.

The state of sensory and motor neurons is assessed by electroneuromyography. The method determines the speed of impulses passing through motor and sensory fibers and records electrical potentials of the brain.

X-ray studies reveal lesions of the spinal column. In addition to general radiography of the spine, X-ray tomography is performed to detect cancer metastases. This allows us to detail the structure of the vertebrae, the condition of the spinal canal, and identify desalination of the meninges, their tumors and cysts. Previous X-ray methods ( pneumomyelography, contrast myelography, spinal angiography, venospondylography) today have given way to painless, safe and highly accurate methods - magnetic resonance and computed tomography. The anatomical structures of the spinal cord and spine are clearly visible on MRI.

Diseases and injuries

A spinal injury can result in a concussion, contusion, or rupture of the spinal cord. The most severe consequences are a rupture - a violation of the integrity of the brain tissue. Symptoms of damage to the brain substance are paralysis of the muscles of the trunk and limbs below the level of injury. After concussions and bruises of the spinal cord, it is possible to treat and restore the function of temporarily paralyzed muscles of the trunk and limbs.

Inflammation of the soft lining of the spinal cord is called meningitis. Treatment of infectious inflammation is carried out with antibiotics, taking into account the sensitivity of the identified pathogen.

When a herniated intervertebral cartilaginous disc prolapses, compression of the nerve root develops. Symptoms of root compression in everyday life are called sciatica. These are severe pain and sensory disturbances along the corresponding nerve. The root is released from compression during a neurosurgical operation to remove an intervertebral hernia. Now such operations are performed by a sparing endoscopic method.

About transplantation

The current level of medicine does not allow spinal cord transplantation. With its traumatic ruptures, patients remain confined to a wheelchair. Scientists are developing methods to restore spinal cord function after severe injury using stem cells. Currently the work is in the experimental stage.

Most severe spinal cord and spinal injuries are the result of motor vehicle accidents or suicide attempts. As a rule, such events occur against the background of alcohol abuse. By refusing excessive libations and following traffic rules, you can protect yourself from serious injuries.