We restore the blood supply to the spinal cord. Blood supply to the spine and spinal cord

From the intracranial part of the vertebral arteries, three descending vessels are formed: one unpaired - the anterior spinal artery and two paired - the posterior spinal arteries that supply the upper cervical segments of the spinal cord.

The rest of the spinal cord is supplied with blood from the main arteries of the trunks located outside the cranial cavity: extracranial segment of the vertebral arteries, subclavian arteries, aorta and iliac arteries (Fig. 1.7.11).

These vessels give special branches - the anterior and posterior radicular-spinal arteries, which go to the spinal cord together, respectively, with its anterior and posterior roots. However, the number of radicular arteries is much less than that of the spinal roots: anterior - 2-6, posterior - 6-12.

When approaching the median fissure of the spinal cord, each anterior radicular-spinal artery is divided into ascending and descending branches, thus forming a continuous arterial trunk - the anterior spinal artery, the ascending continuation of which approximately from level C IV is one nominal unpaired branch of the vertebral arteries.

Anterior radicular arteries

The anterior radicular arteries are not equal in diameter, the largest is one of the arteries (Adamkevich's artery), which enters the spinal canal with one of the roots Th XII -L I, although it can also go with other roots (from Th V to L V).

The anterior radicular arteries are unpaired, the Adamkevich artery often goes on the left.

The anterior radicular arteries give striated, striated-commissural and submersible branches.

Posterior radicular arteries

The posterior radicular arteries are also divided into ascending and descending branches, passing into each other and forming two longitudinal posterior spinal arteries on the posterior surface of the spinal cord.

The posterior radicular arteries immediately form submersible branches.

In general, according to the length of the spinal cord, depending on the options for blood supply, several vertical basins can be distinguished, but more often there are three of them: the lower basin of the Adamkevich artery (the middle lower thoracic regions, as well as the lumbosacral department), the upper one - from the branches of the intracranial part of the vertebral arteries and the middle one (inferior cervical and upper thoracic), supplied from the branches of the extracranial part of the vertebral artery and other branches of the subclavian artery.

With a high location of the artery of Adamkevich, an additional artery is found - the artery of Deprozh - Gauteron. In these cases, the entire thoracic and upper lumbar sections of the spinal cord are supplied by Adamkevich's artery, and the most caudal by an additional one.

Three basins are also distinguished along the diameter of the spinal cord: central (anterior), posterior and peripheral (Fig. 1.7.12). The central basin covers the anterior horns, the anterior commissure, the base of the posterior horn, and the adjacent areas of the anterior and lateral cords.

The central basin is formed by the anterior spinal artery and covers 4/5 of the diameter of the spinal cord. The posterior basin is formed by the system of the posterior spinal arteries. This is the region of the posterior canals and posterior horns. The third, peripheral basin is formed by submersible branches of the perimedullary arterial network, supplied by both the anterior and posterior spinal arteries. It occupies the marginal sections of the anterior and lateral cords.

When the central (front) basin is turned off, the syndrome of ischemia of the anterior half of the spinal cord acutely occurs - Preobrazhensky's syndrome: conduction disturbances of surface sensitivity, pelvic disorders, paralysis. The characteristic of paralysis (flaccid in the legs or flaccid in the arms - spastic in the legs) depends on the level of circulatory shutdown.

Switching off the posterior pool is accompanied by an acute violation of deep sensitivity, which leads to sensitive ataxia and mild spastic paresis in one, two or more limbs - Williamson's syndrome.

Turning off the peripheral pool causes spastic paresis of the extremities and cerebellar ataxia (the spinocerebral pathways suffer). material from the site

Ischemic (atypical) Brown-Sequard syndrome is possible, which occurs when the central pool is turned off unilaterally. This is due to the fact that in the anterior basin the arteries supply only one half of the spinal cord - the right or left. Accordingly, deep sensitivity is not turned off.

The most common syndrome is ischemia of the ventral half of the spinal cord, rarely others. These, in addition to the above, include the syndrome of ischemia of the diameter of the spinal cord. In this case, a picture arises that is similar to that characteristic of myelitis or epiduritis. However, there is no primary purulent focus, fever, inflammatory changes in the blood. Patients, as a rule, suffer from general vascular diseases, frequent heart attacks, transient disorders

The spine and spinal cord are richly supplied with blood, mainly by the metameric arteries, which receive blood from the branches of the aorta.

In the cervical region, such constant sources of blood supply to the vertebrae are the vertebral, deep cervical arteries. In addition, these include non-permanent accessory arteries: the ascending cervical artery and the thyroid trunk. Blood enters the thoracic spine through branches of the intercostal arteries. In the lumbosacral region, the blood supply to the vertebral motor segments and the contents of the spinal canal is provided by the lumbar, middle sacral, ilio-lumbar and lateral sacral arteries. Especially significant is the blood supply to the vertebral segments and the spinal cord LV-SI.

Thus, the blood supply to the vertebrae is usually quite stable, while the blood supply to the intervertebral

discs cease at puberty and the nutrition of the disc tissue is maintained only by diffusion from the parenchyma of the vertebral bodies. This may be one of the reasons for the subsequent development of changes in the structure of the intervertebral discs that form the basis of the spine.

For a long time, the opinion prevailed that there was a dense vascular network in the spinal cord, consisting of three large spinal vessels running longitudinally in relation to it (one anterior and two posterior spinal arteries) and anastomosing with them a large number (theoretically up to 124) anterior and posterior radicular arteries .

Subsequently, it became known that the longitudinal intravertebral, anterior and posterior spinal arteries are discontinuous and are not able to independently provide blood supply to the spinal cord. There was hope that numerous radicular arteries could well cope with this. Back in 1882, the Austrian pathologist A. Adamkevich (Admkiewicz A., 1850-1932) noticed that the blood supply to the spinal cord is not carried out according to a strictly segmental principle. At the same time, the radicular arteries differ significantly in the width of the lumen and in their length. Therefore, only some of them are involved in the blood supply to the spinal cord. Adamkevich described the large anterior radicular artery (Adamkevich's artery). In most people, it is one of the arteries that enters the spinal canal through the intervertebral foramen at the lower thoracic level. Such an artery can be the main source of blood supply to the lower part of the spinal cord (including its lumbar thickening), as well as the cauda equina. In 1889, H. Kadyi suggested that only about 25% of the radicular vessels penetrating the spinal canal participate in the blood supply to the spinal cord.

In 1908, Tanon L., using the method of pouring the thoracic, lumbar and sacral radicular vessels, made sure that "in the human spinal cord, the segmentation of their function is not confirmed," while he noted that most of the radicular arteries participate in the blood supply to the spine does not accept. Depending on the size of the pool of radicular arteries, L. Tanon differentiated them into three categories:

1. the radicular arteries proper, the thinnest, ending within the spinal roots;
2. radicular-shell arteries reaching only the vasculature of the pia mater;
3. radicular-spinal arterial vessels, which are arterial vessels involved in the blood supply to the spine. This classification of the radicular arteries is still recognized as correct in principle.

In 1955, the French Deproges-Gutteron R. described the radicular-spinal artery involved in the blood supply of the epiconus, cone and cauda equina. This artery enters the spinal canal more often with the L5 spinal nerve. Subsequently, it was found that not all people have it and usually takes part in providing blood to the caudal part of the basin of the Adamkevich artery. Thus, it complements the functions of the Adamkiewicz artery, and therefore it became known as the additional anterior radicular artery of Desproges-Hutteron.

A convincing argument in favor of the concept of a non-segmental structure of the spinal cord blood supply system was the clarifying principles of the spinal cord blood supply, established in the course of research by a team of French doctors headed by the neurosurgeon G. Lasorthes (Lasorthes G.). Their results were given in G. Lazorta, A. Gause "Vascularization and hemodynamics of the spinal cord", published in 1973 (Russian translation published in 1977). The authors found that the radicular arteries involved in the blood supply to the spine (radicular-spinal, or radiculo-medullary arteries), having entered the spinal canal, are divided into anterior and posterior branches. The anterior branches involved in the supply of blood to the spinal cord are usually 8-10, while they provide blood supply to 4/5 of the cross section of the spinal cord.

The distribution of the anterior radicular-spinal arterial vessels involved in the blood supply to the spinal cord is uneven and variable. At the same time, most people have anterior radiculo-medullary arteries involved in the blood supply to the cervical segments of the spinal cord, more often than 3, in the upper and middle thoracic regions there are 2-3, at the level of the lower thoracic, lumbar and cauda equina 1-2 arteries. One (the large anterior radicular-medullary artery of Adamkevich, or the artery of the lumbar thickening of Lazorta) is mandatory. It has a diameter of more than 2 mm and enters the spinal canal along with one of the lower thoracic (ThIX, ThX) spinal nerve roots, with 85% on the left and 15% on the right. The second, non-permanent, also unpaired, anterior radicular-medullary artery, known as the additional anterior radicular-medullary artery of Desproges-Hutteron, enters the spinal canal usually together with the 5th lumbar or 1st sacral spinal nerves, it is present in one of 4 or 5 people, that is, in 20-25% of cases.

There are more posterior radicular-spinal arterial vessels than the anterior ones. They take part in the blood supply of 1/5 of the diameter in the posterior part of the spinal cord, including its posterior cords, consisting of conductors of proprioceptive sensitivity (the pathways of Gaulle and Burdach), and the medial sections of the posterior horns. There are about 20 such posterior branches of the radicular medullary arteries, and there are commissural connections between them, so isolated ischemia of the posterior cords is extremely rare.

Thus, when the radicular artery is compressed, ischemia of the corresponding spinal nerve (radiculo-ischemia) occurs, and at the same time, acute or subacute hypalgesia and muscle weakness in the dermatome, myotome and skelerotom corresponding to the affected spinal nerve are possible, which, however, are not always detected due to partial their covering. If the anterior radiculomedullary artery is subjected to compression, the development of radiculomyeloischemia is usually acute with a clinical picture of an almost complete transverse lesion of the spinal nerve, in which only proprioceptive sensitivity pathways are usually preserved below the ischemic focus in the spinal cord, which have better blood supply conditions due to the posterior radicular system. arteries.

In the blood supply to the cervical spine, spinal cord and brain, an important role is played by paired vertebral arteries, which are branches of the subclavian arterial vessels extending from the aorta. First they rise and at the same time move back. Their ex-travertebral section has a length of 5 to 8 cm. At the level of the sixth cervical vertebra, the vertebral arteries, accompanied by para-arterial sympathetic plexuses, enter the channels intended for them - the channels of the vertebral artery, made up of holes in the transverse processes of the vertebrae.

Each of these vertebral arteries is surrounded by a paraarterial autonomic plexus along its entire length. In the process of following these canals of the vertebral arteries, radicular or radicular-medullary arteries depart from them at the level of each intervertebral foramen.

arteries that pass through these openings along with the spinal nerves into the spinal canal. The radicular-medullary arteries play a leading role in the blood supply to the cervical spinal cord. The largest of them is called the artery of the cervical thickening (Lazort).

The main trunks of the vertebral arteries rise to exit from the holes in the transverse processes of the axis; after that, they deviate outwards at an angle of about 45° and enter the homolateral transverse foramina of the atlas (C1 vertebra). Having passed through it, as well as through the atlanto-occipital membrane and the bony foramen magnum, the vertebral arterial vessels enter the cranial cavity, where they give off one branch each, which is the beginning of two posterior spinal arterial vessels. At the same time, each of them at the level of the Cn segment of the spinal cord gives off along the anastomosis, which, merging, form an unpaired anterior spinal artery.

Two posterior and one anterior spinal arterial vessels supply blood mainly to the upper cervical spinal region, and then go down and, at the same time, participate in the blood supply of the spine to the extent possible. However, they are soon fragmented, sometimes interrupted. As a result, these longitudinal spinal arteries usually play an auxiliary role in the blood supply to the spine and spinal cord, while the anterior radicular medullary arteries are the main sources of blood supply to the spinal cord.

The vertebral arteries that have entered the cranial cavity, having approached the posterior edge of the brain bridge, are connected into a single basilar artery. Thus, the vertebrobasilar system is involved in the blood supply to the upper cervical region and provides blood to the brainstem, cerebellum, is involved in the blood supply to the structures of the diencephalon, in particular the hypothalamic region and thalamus, as well as the occipital lobes and the occipito-parietal zone of the cerebral cortex.

The innervation of the vertebral arteries is provided by the paraarterial autonomic plexuses surrounding them, which have a connection with the ganglia of the paravertebral sympathetic chains. Nerve branches also depart from these plexuses, heading to the cervical vertebrae. They are involved in the innervation of the periosteum, joint capsules, ligaments and other connective tissue structures of the spine.

Cerebral circulation has some anatomical and functional features, the knowledge of which is necessary for neurologists to better understand the pathogenesis of many diseases of the nervous system.

Blood supply to the brain

The brain is supplied with arterial blood from two pools: carotid and vertebrobasilar.

The system of the carotid basin in its initial segment is represented by the common carotid arteries. The right common carotid artery is a branch of the brachiocephalic trunk, the left one directly departs from the aorta. At the level of the upper edge of the thyroid cartilage, the common carotid artery branches into the external and internal carotid arteries. Then, through the foramen caroticum, the internal carotid artery enters the canalis caroticum of the pyramid of the temporal bone. After the artery leaves the canal, it passes along the anterior side of the body of the pterygoid bone, enters the sinus cavernosus of the dura and reaches the place under the anterior perforated substance, where it divides into terminal branches. An important collateral branch of the internal carotid artery is the ophthalmic artery. Branches depart from it, irrigating the eyeball, lacrimal gland, eyelids, forehead skin and, partially, the walls of the nasal cavities. Terminal branches a. ophthalmica - supratrochlear and supraorbital anastomose with branches of the external carotid artery.

Then the artery lies in the Sylviian furrow. The terminal branches of the internal carotid artery are represented by 4 arteries: the posterior communicating artery, which anastomoses with the posterior cerebral artery, which is a branch of the basilar artery; the anterior villous artery, which forms the choroid plexuses of the lateral cerebral ventricles and plays a role in the production of cerebrospinal fluid and blood supply to some nodes of the base of the brain; anterior cerebral artery and middle cerebral artery.

The internal carotid artery connects to the posterior cerebral artery through the posterior communicating arteries. The anterior cerebral arteries are connected to each other through the anterior communicating artery. Thanks to these anastomoses, the arterial circle of Willis, circulus arteriosus cerebry, is formed at the base of the brain. The circle connects the arterial systems of the carotid and vertebrobasilar basins.

Already within the circle of Willis, the anterior cerebral artery gives off several small branches from itself - the anterior perforating arteries - aa. perforante arterios. They pierce the anterior perforated plate and nourish part of the head of the caudate nucleus. The largest of these is the recurrent artery of Geibner, which feeds the anteromedial sections of the head of the caudate nucleus, the putamen, and the anterior two-thirds of the anterior leg of the internal capsule. The anterior cerebral artery itself lies above the corpus callosum and supplies arterial blood to the medial surface of the hemispheres from the frontal pole to the fissura parieto-occipitalis and the anterior two-thirds of the corpus callosum. Also, its branches can enter the orbital region of the base of the brain and the lateral surface of the frontal pole, superior frontal gyrus and paracentral lobule.

The middle cerebral artery is the largest. It lies in the Sylvian sulcus and supplies the entire convexital surface of the hemispheres (with the exception of areas irrigated by the anterior and posterior cerebral arteries) - the lower and middle frontal gyrus, the anterior and posterior central gyrus, the supramarginal and angular gyrus, the rail island, the outer surface of the temporal lobe, the anterior sections occipital lobe. Within the circle of Willis, the middle cerebral artery gives off several thin trunks that pierce the lateral parts of the anterior perforated plate, the so-called aa. perforantes mediales et laterales. The largest of the perforating arteries are aa. lenticulo-striatae and lenticulo-opticae. They supply blood to the subcortical nodes of the hemispheres, the fence, the posterior third of the anterior leg and the upper part of the posterior leg of the internal capsule.

The vertebrobasilar basin in its proximal section is represented by the vertebral arteries that branch off from the subclavian arteries at the level of the transverse process of the VI cervical vertebra (segment V1). Here it enters the opening of its transverse process and rises up along the canal of the transverse processes to the level of the II cervical vertebra (segment V2). Further, the vertebral artery turns backwards, goes to for. transversarium of the atlas (segment V3), passes it and lies down in sulcus a. vertebralis. In the extracranial section, the artery gives off branches to the muscles, bone and ligamentous apparatus of the cervical spine, and takes part in the nutrition of the meninges.

The intracranial vertebral artery is the V4 segment. In this department, branches depart to the dura mater of the posterior cranial fossa, the posterior and anterior spinal arteries, the posterior inferior cerebellar artery, and the paramedian artery. The posterior spinal artery is a steam room. It is located in the posterior lateral groove of the spinal cord and is involved in the blood supply to the nuclei and fibers of the thin and wedge-shaped bundles. Anterior spinal artery - unpaired is formed as a result of the merger of two trunks extending from the vertebral arteries. It supplies the pyramids, the medial loop, the medial longitudinal bundle, the nuclei of the hypoglossal nerve and the solitary tract, and the dorsal nucleus of the vagus nerve. The posterior inferior cerebellar artery is the largest branch of the vertebral artery and supplies the medulla oblongata and the lower cerebellum. Paramedian branches provide blood supply to the ventral and lateral sections of the medulla oblongata and roots of the IX-XII pairs of cranial nerves.

At the posterior edge of the pons, both vertebral arteries merge to form the main artery - a. basilaris. It lies in the groove of the bridge and on the slope of the occipital and sphenoid bones. Paramedian branches, short envelopes, long envelopes (paired - the lower anterior cerebellar and superior cerebellar arteries) and the posterior cerebral arteries depart from it. Of these, the largest are the inferior anterior cerebellar, superior cerebellar and posterior cerebral arteries.

The inferior anterior cerebellar artery departs from the main one at the level of its middle third and supplies blood to a piece of the cerebellum and a number of lobes on its anteroinferior surface.

The superior cerebellar artery departs from the upper part of the basilar artery and supplies the upper half of the cerebellar hemispheres, the vermis, and partially the quadrigemina.

The posterior cerebral artery is formed by division of the basilar artery. It nourishes the roof of the midbrain, the brain stem, the thalamus, the lower internal sections of the temporal lobe, the occipital lobe and partially the upper parietal lobule, gives small branches to the choroid plexus of the third and lateral ventricles of the brain.

Between the arterial systems there are anastomoses that begin to function when any one arterial trunk is occluded. There are three levels of collateral circulation: extracranial, extra-intracranial, intracranial.

The extracranial level of collateral circulation is provided by the following anastomoses. With occlusion of the subclavian artery, blood flow is carried out:

 from the contralateral subclavian artery through the vertebral arteries;

 from the homolateral vertebral artery through the deep and ascending arteries of the neck;

 from the contralateral subclavian artery through the internal mammary arteries;

 from the external carotid artery through the superior and inferior thyroid arteries.

With occlusion of the initial section of the vertebral artery, the flow is carried out from the external carotid artery through the occipital artery and the muscular branches of the vertebral artery.

Extra-intracranial collateral circulation is carried out between the external and internal carotid arteries through the supraorbital anastomosis. Here the supratrochlear and supraorbital arteries from the internal carotid artery system and the terminal branches of the facial and superficial temporal arteries from the external carotid artery system are connected.

At the intracranial level, collateral circulation is carried out through the vessels of the circle of Willis. In addition, there is a cortical anastomotic system. It consists of anastomoses on the convexital surface of the hemispheres. Anastomose the terminal branches of the anterior, middle and posterior cerebral arteries (in the region of the superior frontal sulcus, at the border of the upper and middle thirds of the central gyri, along the interparietal sulcus, in the region of the superior occipital, inferior and middle temporal, in the region of the wedge, precuneus and ridge of the corpus callosum) . From the anastomotic network under the pia mater, perpendicular branches extend deep into the gray and white matter of the brain. They form anastomoses in the region of the basal ganglia.

The venous system of the brain takes an active part in blood circulation and cerebrospinal fluid circulation. The veins of the brain are divided into superficial and deep. Superficial veins lie in the cells of the subarachnoid space, anastomose and form a looped network on the surface of each of the hemispheres. They drain venous blood from the cortex and white matter. The outflow of blood from the veins goes to the nearest cerebral sinus. Blood from the outer and medial sections of the frontal, central, and parietal-occipital regions flows mainly into the superior sagittal sinus, and to a lesser extent into the transverse, straight, cavernous, and parietal-basic sinuses. In the deep veins of the brain, the outflow of blood comes from the veins of the choroid plexus of the lateral ventricles, subcortical nodes, visual tubercles, midbrain, pons, medulla oblongata and cerebellum. The main collector of this system is the large vein of Galen, which flows into the straight sinus under the cerebellum. Blood from the superior sagittal and rectus sinuses enters the transverse and sigmoid sinuses and is drained into the internal jugular vein.

Blood supply to the spinal cord

The beginning of the study of the blood supply to the spinal cord dates back to 1664, when the English physician and anatomist T. Willis pointed out the existence of the anterior spinal artery.

According to the length, three arterial basins of the spinal cord are distinguished - cervicothoracic, thoracic and lower (lumbar-thoracic):

 The cervicothoracic basin supplies the brain with blood at the C1-D3 level. In this case, the vascularization of the uppermost parts of the spinal cord (at the C1-C3 level) is carried out by one anterior and two posterior spinal arteries, which branch off from the vertebral artery in the cranial cavity. Throughout the rest of the spinal cord, blood supply comes from the system of segmental radiculomedullary arteries. At the middle, lower cervical and upper thoracic levels, the radiculomedullary arteries are branches of the extracranial vertebral and cervical arteries.

 In the thoracic basin, there is the following scheme for the formation of radiculomedullary arteries. The intercostal arteries depart from the aorta, giving off dorsal branches, which in turn are divided into the musculocutaneous and spinal branches. The spinal branch enters the spinal canal through the intervertebral foramen, where it divides into the anterior and posterior radiculomedullary arteries. The anterior radiculomedullary arteries merge to form one anterior spinal artery. The posterior form the two posterior spinal arteries.

 In the lumbar-thoracic region, dorsal branches depart from the lumbar arteries, lateral sacral arteries, and iliac-lumbar arteries.

Thus, the anterior and posterior lumbar arteries are a collection of terminal branches of the radiculomedullary arteries. At the same time, along the course of the blood flow, there are zones with opposite blood flow (at the places of branching and junction).

There are zones of critical circulation where spinal ischemic strokes are possible. These are the junction zones of the vascular basins - CIV, DIV, DXI-LI.

In addition to the spinal cord, the radiculomedullary arteries supply blood to the membranes of the spinal cord, spinal roots, and spinal ganglia.

The number of radiculomedullary arteries varies from 6 to 28. At the same time, there are fewer anterior radiculomedullary arteries than the posterior ones. Most often, there are 3 arteries in the cervical part, 2-3 in the upper and middle thoracic, and 1-3 in the lower thoracic and lumbar.

The following major radiculomedullary arteries are distinguished:

1. Artery of the cervical thickening.

2. Large anterior radiculomedullary artery of Adamkevich. It enters the spinal canal at the level of DVIII-DXII.

3. Inferior radiculomedullary artery of Desproges-Gutteron (available in 15% of people). Included at the LV-SI level.

4. Superior accessory radiculomedullary artery at the DII-DIV level. Occurs with the main type of blood supply.

According to the diameter, three arterial pools of blood supply to the spinal cord are distinguished:

1. The central zone includes the anterior horns, the periependymal gelatinous substance, the lateral horn, the base of the posterior horn, Clark's columns, the deep sections of the anterior and lateral columns of the spinal cord, and the ventral part of the posterior cords. This zone is 4/5 of the entire diameter of the spinal cord. Here, the blood supply comes from the anterior spinal arteries due to the striated submerged arteries. There are two of them on each side.

2. The posterior arterial zone includes the posterior columns, the tops of the posterior horns, and the posterior sections of the lateral columns. Here the blood supply comes from the posterior spinal arteries.

3. Peripheral arterial zone. The blood supply here is carried out from the system of short and long circumflex arteries of the perimedullary vasculature.

The venous system of the spinal cord has a central and peripheral sections. The peripheral system collects venous blood from the peripheral parts of the gray and mainly the peripheral white matter of the spinal cord. It flows into the venous system of the pial network, which forms the posterior spinal or posterior spinal vein. The central anterior zone collects blood from the anterior commissure, the medial and central parts of the anterior horn, and the anterior funiculus. The posterior central venous system includes the posterior cords and posterior horns. Venous blood flows into the striated veins, and then into the anterior spinal vein, located in the anterior fissure of the spinal cord. From the pial venous network, blood flows through the anterior and posterior radicular veins. The radicular veins merge into a common trunk and drain into the internal vertebral plexus or intervertebral vein. From these formations, venous blood flows into the system of the superior and inferior vena cava.

Meninges and cerebrospinal fluid circulation pathways

The brain has three shells: the outermost hard shell - dura mater, under it lies the arachnoid - arachnoidea, under the arachnoid, directly adjacent to the brain, lining the furrows and covering the gyrus, lies the pia mater. The space between the dura mater and the arachnoid is called subdural, between the arachnoid and soft subarachnoid.

Dura mater has two leaves. The outer leaf is the periosteum of the bones of the skull. The inner lamina is connected to the brain. The dura mater has the following processes:

 large crescent process, falx cerebry major, located between both hemispheres of the brain from cristae Galii in front along the sagittal suture to protuberantia occipitalis interna behind;

 small crescent process, falx cerebry minor, goes from protuberantia occipitalis interna to foramen occipitale magnum between the hemispheres of the cerebellum;

 tentorium cerebelli, separates the dorsal surface of the cerebellum from the lower surface of the occipital lobes of the brain;

 the diaphragm of the Turkish saddle is stretched over the Turkish saddle, under it lies an appendage of the brain - the pituitary gland.

Between the sheets of the dura mater and its processes are sinuses - receptacles of venous blood:

1. Sinus sagittalis superior - the superior longitudinal sinus runs along the upper edge of the greater falciform process.

2. Sinus sagittalis inferior - the lower sagittal sinus runs along the lower edge of the large falciform process.

3. Sinus rectus. Sinus sagittalis inferior flows into it. The straight sinus reaches the protuberantia occipitalis interna and merges with the sinus sagittalis superior.

4. In the transverse direction from protuberantia occipitalis interna goes the largest sinus transverses - the transverse sinus.

5. In the region of the temporal bone, it passes into the sinus sigmoideus, which descends to the foramen jugulare and passes into the bulbus superior v. jugulare.

6. Sinus cavernosus - the cavernous sinus is placed on the lateral surface of the Turkish saddle. n are placed in the walls of the sinus. oculomotorius, n. trochlearis, n. ophthalmicus, n. abducens. Inside the sinus passes a. carotis interna. In front of the pituitary gland is the sinus intercavernosus anterior, and behind the sinus intercavernosus posterior. Thus, the pituitary gland is surrounded by a circular sinus.

7. Sinus petrosus superior is located along the upper edge of the pyramid of the temporal bone. It connects sinus cavernosus with sinus transversus.

8. Sinus petrosus inferior lies in the groove of the same name and connects sinus cavernosus with bulbus superior v. jugulare.

9. Sinus occipitalis covers the edges of the foramen magnum and joins the sinus sigmoideus.

The confluence of the sinuses is called confluens sinuum. Blood flows from it into the jugular vein.

The arachnoid is located between the dura and pia mater. On both sides it is lined with endothelium. The outer surface is loosely connected to the dura mater by cerebral veins. The inner surface faces the pia mater, is connected to it by trabeculae, and above the convolutions is tightly fused with it. This is how cisterns are formed in the area of ​​the furrows.

The following tanks are distinguished:

 cisterna cerebello-oblongata, or a large cistern of the brain, is located between the lower surface of the cerebellum and the dorsal surface of the medulla oblongata;

 cisterna fossae Silvii - located in the region of the Sylvius furrow;

 cisterna chiasmatis - located in the region of the optic chiasm;

 cisterna interpeduncularis - located between the legs of the brain;

 cisterna pontis - located on the lower surface of the pons;

 cisterna corporis callosi - located along the dorsal surface of the corpus callosum;

 cisterna ambiens - located between the occipital lobes of the brain and the upper surface of the cerebellum;

 cisterna terminalis, dural sac from level LII, where the spinal cord ends to SII-SIII vertebrae.

All cisterns communicate with each other and with the subarachnoid space of the brain and spinal cord.

Pachion granulations are ectropions of the arachnoid membrane, pushed into the lower wall of the venous sinuses and the skull bones. This is the main place for the outflow of cerebrospinal fluid into the venous system.

The pia mater is adjacent to the surface of the brain, goes into all the furrows and crevices. Richly supplied with blood vessels and nerves. In the form of a double-folded sheet, it penetrates into the cavity of the ventricles and takes part in the formation of the choroid plexuses of the ventricles.

January 16, 2011

The spine is supplied with blood by paired arterial vessels. In the cervical region, these are branches of the vertebral artery, the ascending artery of the neck, and the deep artery of the neck. These same arterial vessels give off special branches involved in the blood supply to the cervical spinal cord. In the thoracic region, the tissues of the vertebral segments are supplied with blood by the branches of the intercostal arteries, and in the lumbar region, by the paired lumbar arteries. The intercostal and lumbar arteries give branches to the vertebral bodies along the way. These springs, branching, enter the vertebral bodies through nutrient holes. At the level of the transverse processes, the lumbar and intercostal arteries give off posterior branches, from which the spinal (radicular) branches are immediately separated. Further, the dorsal arteries branch out, supplying blood to the soft tissues of the back and vertebral arches.

In the vertebral bodies, arterial branches divide, forming a dense arterial network. Near the hyaline endplates, it forms vascular lacunae. Due to the expansion of the vascular bed, the blood flow velocity in the lacunae slows down, which is important for the trophism of the central sections of the intervertebral discs, which in adults do not have their own vessels and are fed by osmosis and diffusion through the hyaline endplates.

The longitudinal ligaments and the outer layers of the annulus fibrosus have vessels, are well supplied with blood and take part in the trophism of the central sections of the intervertebral discs.

The vertebral arteries of the cervical region arise from the subclavian, follow cranially anterior to the costal-transverse processes of the C7 vertebra, enter the canal of the vertebral artery at the level of the transverse foramen of the C6 vertebra and follow upward in the canal. At the level of the supratransverse foramen of the C2 vertebra, the vertebral arteries deviate outward and enter the transverse foramen of the atlas, bend sharply, bypassing the atlantooccipital joint behind and following in the groove of the vertebral artery on the upper surface of the posterior arch of the atlas. Coming out of it, the arteries bend steeply backwards, bypass the atlantooccipital joints behind, pierce the posterior atlantooccipital membrane and along the a.vertebralis groove on the upper surface of the posterior arch of the atlas, enter through the foramen magnum into the cranial cavity, where they join in a. basilaris, which, together with other arteries, forms the circle of Willis.

The vertebral artery is surrounded by a plexus of sympathetic nerves, which together form the vertebral nerve. The vertebral arteries and the surrounding vertebral nerve run anterior to the spinal nerves and slightly outward from the lateral surfaces of the cervical vertebral bodies. With uncovertebral arthrosis, the vertebral arteries can become deformed, but the main cause of impaired blood flow along the a vertebralis is their spasm due to irritation of the vertebral nerve fibers.

The loop of the vertebral artery at the level of the arch of the atlas is very important, since it creates a certain reserve of length, therefore, during flexion and rotation in the atlantooccipital joint, the blood supply through the arteries is not disturbed.

The anterior and two posterior spinal arteries depart from the vertebral arteries in the cranial cavity above the anterior margin of the foramen magnum. The anterior spinal artery follows the anterior fissure of the spinal cord throughout its entire length, giving branches to the anterior sections of the spinal cord in the circumference of the central canal. The posterior spinal arteries follow the line of entry into the spinal cord of the posterior radicular filaments throughout the entire length of the spinal cord, anastomosing between themselves and the spinal branches extending from the vertebral, intercostal and lumbar arteries.

Anastomoses between the anterior and posterior spinal arteries give branches to the spinal cord, which together form a kind of crown of the spinal cord. The vessels of the crown supply blood to the superficial areas of the spinal cord adjacent to the pia mater.

The anterior spinal artery supplies blood to about 80% of the diameter of the spinal cord: the anterior and lateral cords of the white matter, the anterior and lateral horns of the spinal cord, the bases of the posterior horns, the substance of the brain around the central canal, and partially the posterior cords of the white matter

The posterior spinal arteries supply blood to the posterior horns of the spinal cord, most of the posterior cords, and the dorsal sections of the lateral cords. Gol's bundle is supplied with blood from both the pool of the right and left posterior spinal arteries, and Burdakh's bundle is supplied only from the artery of its side.

The parts of the spinal cord substance located in critical zones between the basins of the anterior and posterior spinal arteries are the worst supplied with blood: the bases of the posterior horns, the substance of the brain in the circumference of the central canal, including the posterior commissure, as well as Clarke's nucleus.

Thus, the blood supply to the spinal cord is segmental, but there are additional radiculomedullary arteries: the spinal branch of the fourth intercostal artery, the spinal branch of the 11-12 intercostal artery (Adamkiewicz artery) and the lower additional radiculomedullary artery (Deproj-Getteron artery). The latter departs from the internal iliac artery and, together with one of the caudal lumbar spinal nerves and its roots, reaches the cone and epiconus of the spinal cord. These four arterial vessels play a leading role in the blood supply to the spinal cord and its elements. Other spinal branches are of auxiliary importance, but under certain conditions, for example, when there is insufficient blood flow in one of the main spinal branches, these arteries are involved in compensating for impaired blood supply.

Along the length of the spinal cord, there are also zones of less reliable blood supply located at the boundaries of the pools of additional radiculomedullary arteries. Since the number of the latter and the level of their entry into the spinal cord are very variable, the location of the critical zones is not the same in different subjects. Most often, such zones include the upper 5-7 thoracic segments, the area of ​​the brain above the lumbar thickening and the terminal area of ​​the spinal cord.

The roots of the spinal nerves and the Nageotte nerve (part of the spinal nerve from the spinal node to the place where the “cuff” of the nerve leaves the dura mater) are supplied with blood from two sources: the radicular branches of the anterior and posterior spinal arteries going in the distal direction.

In the "watershed" area of ​​these joints, there is a root area with depleted arterial blood supply. Violation of blood flow along any of the radicular arterial branches primarily causes ischemia of this particular area.

In the bodies of the vertebrae, the main part of the venous blood is collected in collectors that go to the back surface of the bodies, leave it and then flow into the anterior internal vertebral plexus. A smaller part of the veins of the vertebral body exits through the nutrient holes and flows into the anterior external venous plexus. Similarly, venous blood from the vertebral arches is collected in the external and internal posterior venous plexuses of the spine.

The right and left parts of the anterior internal venous plexus are connected by transverse branches, forming venous rings and anastomose with the posterior internal venous plexus. In turn, the internal and external venous plexuses also anastomize with each other and form the lumbar and posterior intercostal branches. The latter flow into the unpaired and semi-unpaired veins, but are connected by anastomoses with the system of the inferior and superior vena cava. The superior 2-5 lumbar veins also flow into the unpaired and semi-unpaired veins, which carry blood to the system of the superior vena cava, and the inferior 2-3 lumbar veins run caudally and form a short and thick iliac-lumbar trunk that flows into the common iliac vein. Thus, the venous plexus of the spine is a caval-caval anastomosis. With insufficient blood outflow in the system of the inferior vena cava, the pressure in the lower lumbar part of the vertebral plexuses can increase significantly, and lead to varicose veins of the spinal canal, venous congestion and trophic disturbance not only of the tissues of the vertebral segment, but also of the spinal nerves, cauda equina roots, and even cone of the spinal cord.

The anastomoses between the internal and external venous plexuses are the veins of the intervertebral foramen. Each intervertebral foramen contains 4 veins, one artery and a spinal nerve. Blood from the spinal cord is escorted into the radicular veins, which empty into the veins of the vertebral plexuses or directly into the vertebral veins.

It must be remembered that there are arterio-venous anastomoses between the arterial and venous system. Such arteriovenous shunts are found in all tissues and organs; they play an important role in the regulation of blood supply. However, in the spinal cord they sometimes transform the nature of vascular malformations. A massive discharge of arterial blood into the venous bed causes insufficiency of venous outflow, varicose veins and edema associated with venous insufficiency, dystrophy, and degenerative changes in the spinal cord.

), departs from the subclavian artery immediately after its exit from the chest cavity. In its course, the artery is divided into four parts. Starting from the superomedial wall of the subclavian artery, the vertebral artery goes upward and somewhat backward, located behind the common carotid artery along the outer edge of the long muscle of the neck (prevertebral part, pars prevertebralis).

Then it enters the opening of the transverse process of the VI cervical vertebra and rises vertically through the openings of the same name in all cervical vertebrae. [transverse process (cervical) part, pars transversaria (cervicalis)].

Coming out of the opening of the transverse process of the II cervical vertebra, the vertebral artery turns outward; approaching the opening of the transverse process of the atlas, goes up and passes through it (Atlantic part, pars atlantis). Then it follows medially in the groove of the vertebral artery on the upper surface of the atlas, turns upward and, piercing the posterior atlantooccipital membrane and the dura mater, enters through the foramen magnum into the cranial cavity, into the subarachnoid space (intracranial part, pars intracranialis).

In the cavity of the skull, heading up the slope and somewhat anteriorly, the left and right vertebral arteries converge, following the surface of the medulla oblongata; at the posterior edge of the bridge of the brain, they are interconnected, forming one unpaired vessel - basilar artery, a. basilaris. The latter, continuing its path along the slope, is adjacent to the basilar sulcus, the lower surface of the bridge, and at its front edge is divided into two - right and left - posterior cerebral arteries.

From vertebral artery the following branches depart.

1. Muscular branches, rr. musculares, to the prevertebral muscles of the neck.
2. Spinal (radicular) branches, rr. spinales (radiculares), depart from that part of the vertebral artery that passes through the vertebral arterial opening. These branches pass through the intervertebral foramens of the cervical vertebrae into the spinal canal, where they supply the spinal cord and its membranes with blood.
3. , steam room, departs on each side from the vertebral artery in the cranial cavity, slightly above the foramen magnum. It goes down, enters the spinal canal and along the posterior surface of the spinal cord, along the line of entry into it of the posterior roots (sulcus lateralis posterior), reaches the region of the cauda equina; blood supply to the spinal cord and its membranes.

   The posterior spinal arteries anastomose with each other, as well as with the spinal (radicular) branches from the vertebral, intercostal and lumbar arteries (see Fig.).

Anterior spinal artery, a. spinalis anterior, starts from the vertebral artery above the anterior edge of the foramen magnum.

It goes down, at the level of the intersection of the pyramids, it connects with the artery of the same name on the opposite side, forming one unpaired vessel. The latter descends along the anterior median fissure of the spinal cord and ends in the region of the filum terminale; blood supply to the spinal cord and its membranes and anastomoses with the spinal (radicular) branches from the vertebral, intercostal and lumbar arteries.

Posterior inferior cerebellar artery, a. inferior posterior cerebelli(see fig.), branches in the lower posterior part of the cerebellar hemispheres. The artery gives off a number of small branches: to the choroid plexus of the IV ventricle - villous branch of the fourth ventricle, r. choroideus ventriculi quarti; to the medulla oblongata lateral and medial cerebral branches (branches to the medulla oblongata), rr. medullares laterales and mediales (rr. ad medullam oblongatum); to the cerebellum branch of the cerebellar tonsil, r, tonsillae cerebelli.

From the inner part of the vertebral artery depart meningeal branches, rr. meningei, which supply blood to the dura mater of the posterior cranial fossa.

From basilar artery(see fig.,) the following branches depart.

1. Artery of the labyrinth, a. labyrinthi, goes through the internal auditory opening and passes along with the vestibulocochlear nerve, n. vestibulocochlearis, to the inner ear.
2. Anterior inferior cerebellar artery, a. inferior anterior cerebelli, - the last branch of the vertebral artery, can also depart from the basilar artery. Blood supply to the anteroinferior cerebellum.
3. Bridge arteries, aa. pontis, enter the substance of the bridge.
4. Superior cerebellar artery, a. superior cerebelli, starts from the basilar artery at the anterior edge of the bridge, goes outward and backward around the legs of the brain and branches in the region of the upper surface of the cerebellum and in the choroid plexus of the third ventricle.
5. Middle cerebral arteries, aa. mesencephalicae, depart from the distal part of the basilar artery, symmetrically, 2-3 trunks to each leg of the brain.
6. Posterior spinal artery, a. spinalis posterior, steam room, lies medially from the posterior root along the posterolateral groove. It starts from the basilar artery, goes down, anastomosing with the artery of the same name on the opposite side; blood supply to the spinal cord.

Posterior cerebral arteries, aa. cerebri posteriores(see fig. , , ), are first directed outward, located above the cerebellar integument, which separates them from the superior cerebellar arteries and the basilar artery located below. Then they wrap back and up, go around the outer periphery of the legs of the brain and branch out on the basal and partly on the upper lateral surface of the occipital and temporal lobes of the cerebral hemispheres. They give branches to the indicated parts of the brain, as well as to the posterior perforated substance to the nodes of the large brain, the legs of the brain - peduncle branches, rr. pedunculares, and the choroid plexus of the lateral ventricles - cortical branches, rr. corticales.

Each posterior cerebral artery is conditionally divided into three parts: pre-communication, running from the beginning of the artery to the confluence of the posterior communicating artery, a. communicans posterior (see Fig.,,); postcommunication, which is a continuation of the previous one and passes into the third, final (cortical), part, which gives off branches to the lower and medial surfaces of the temporal and occipital lobes.

A. From the pre-communication part, pars precommunicalis, depart posteromedial central arteries, aa. centrales posteromediales. They penetrate through the posterior perforated substance and break up into a series of small stems; blood supply to the ventrolateral nuclei of the thalamus.

B. Postcommunication part, pars postcommunicalis, gives the following branches.

1. Posterolateral central arteries, aa. centrales posterolaterales, are represented by a group of small branches, some of which supply blood to the lateral geniculate body, and some end in the ventrolateral nuclei of the thalamus.
2. Thalamic branches, rr. thalamici, small, often depart from the previous ones and supply blood to the lower medial parts of the thalamus.
3. Medial posterior villous branches, rr. choroidei posteriores mediales, go to the thalamus, supplying its medial and posterior nuclei with blood, approach the choroid plexus of the third ventricle.
4. Lateral posterior villous branches, rr. choroidei posteriores laterales, approach the posterior parts of the thalamus, reaching the choroid plexus of the third ventricle and the outer surface of the epiphysis.
5. Leg branches, rr. pedunculares supply blood to the midbrain.

B. The final part (cortical), pars terminalis (corticalis), the posterior cerebral artery gives off two occipital arteries - lateral and medial.

1. Lateral occipital artery, a. occipitalis lateralis, goes backwards and outwards and, branching into anterior, intermediate and posterior branches, sends them to the lower and partially medial surfaces of the temporal lobe:

• anterior temporal branches, rr. temporales anteriores, depart in the amount of 2-3, and sometimes with a common trunk and then, branching, go anteriorly, go along the lower surface of the temporal lobe. Blood supply to the anterior sections of the parahippocampal gyrus, reaching the hook;
• temporal branches (medial intermediate), rr. temporales (intermedia mediales), are directed downward and anteriorly, distributed in the region of the lateral occipital-temporal gyrus, and reach the inferior temporal gyrus;
• posterior temporal branches, rr. temporales posteriores, only 2-3, are directed downward and backward, pass along the lower surface of the occipital lobe and are distributed in the region of the medial occipitotemporal gyrus.

2. Medial occipital artery, a. occipitalis medialis, is actually a continuation of the posterior cerebral artery. A number of branches depart from it to the medial and lower surfaces of the occipital lobe:

• dorsal branch of the corpus callosum, r. corporis callosi dorsalis, - a small branch, goes up along the back of the cingulate gyrus and reaches the ridge of the corpus callosum, supplies blood to this area, anastomoses with the terminal branches of the corpus callosum, a. callosomarginalis;
• parietal branch, r. parietails, can depart both from the main trunk and from the previous branch. It is directed somewhat backwards and upwards; blood supply to the area of ​​the medial surface of the temporal lobe, in the region of the anteroinferior part of the precuneus;
• parieto-occipital branch, r. parietooccipitalis, departs from the main trunk upwards and backwards, lying along the furrow of the same name, along the anterior upper edge of the wedge; blood supply to this area;
• spur branch, r. calcarinus, - a small branch, departs from the medial occipital artery backwards and downwards, repeats the course of the spur groove. Passes along the medial surface of the occipital lobe; blood supply to the lower part of the wedge;
• occipitotemporal branch, r. occipitotemporalis, departs from the main trunk and goes downward, backward and outward, lying along the medial occipital-temporal gyrus; blood supply to this area.