Blood supply to the spinal cord. Blood supply to the spine and spinal cord Syndromes due to lesions of the spinal vessels
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 pool 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 areas 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
Although the radicular arteries originating from the aorta accompany the nerve roots at many levels, most of them do not take part in the blood supply of the SC itself. The main blood supply to the anterior parts of the SM comes only from 6-8 radicular (the so-called "radiculo-medullary") arteries. They depart at strictly defined levels, but the direction of departure may vary73 (p. 1180-1):
C3 - departs from the vertebral artery
C6 - usually originates from the deep cervical artery
C8 - usually departs from the costocervical trunk
NB: C6 and C8: ≈10% of the population does not have an anterior radicular (spinal?) artery at the inferior cervical level14
Adamkevich's artery (see below)
The paired posterior arteries are less clearly developed than the anterior spinal artery; they receive blood supply from 10-23 radicular branches.
The blood supply to the thoracic SM is limited and borderline; it receives blood only from the above T4 or T5 radicular arteries. Therefore, this area is more prone to vascular disorders.
Rice. 3-8. Diagram of the blood supply to the spinal cord (according to J.M. Traveras, E.H. Woods (eds) Diagnostic Neurology, 2nd ed., vol. II, p. 1181, ©1976, the Williams & Wilkins Co., Baltimore; with permission and with modifications)
Adamkevich's artery (the so-called large anterior radicular artery)
the main source of blood supply to the SC throughout from ≈T8 to the cone
in 80% of cases departs between T9 and L2 (between T9 and T12 in 75% of cases); in the remaining 15% of cases, it departs higher between T5 and T8 (in these cases, there may be an additional radicular artery below)
usually quite large, giving branches in rostral and caudal directions (the latter is usually larger), which on AG has the characteristic appearance of a hairpin
3.4. Cerebrovascular Anatomy
3.4.1. Vascular cerebral pools
On fig. 3-9 shows the territories supplied by the main cerebral arteries. Both the main cerebral arteries15 and the arteries supplying the central parts of the brain [lenticulostriate arteries, recurrent Hübner arteries (the so-called middle striatal artery), etc.] are characterized by significant variability both in the areas of their blood supply and in the places their departure from PMA and SMA.
Rice. 3-9. Blood supply pools of the cerebral hemispheres
3.4.2. Arterial blood supply to the brain
The symbol "" denotes the area supplied by the indicated artery. Angiographic diagrams of the described vessels, see Cerebral angiography, p.557.
circle of willis
A correctly formed circle of Willis is present only in 18% of cases. Hypoplasia of one or both PCAs occurs in 22-32% of cases; segment A1 may be hypoplastic or absent in 25% of cases.
In 15-35% of cases, one PCA receives its blood supply through the PCA from the ICA, and not from the IBS, and in 2% of cases, both PCA receive blood from the PCA (fetal blood supply).
NB: The PSA is located above the superior surface of the optic chiasm.
Anatomical segments of the intracranial cerebral arteries
Tab. 3-9. Segments of the internal carotid artery
carotid artery: the traditional numerical system for naming segments16 was in the rostral-caudal direction (i.e. against the direction of blood flow, as well as nomenclature systems for other arteries). A number of other nomenclature systems have been proposed to overcome this discrepancy, as well as to designate anatomically important segments that were not originally considered (see, for example, Table 3-917). See details below
anterior cerebral artery (ACA)18, segments:
A1: ACA from orifice to ACA
A2: ACA from the PSA to the origin of the calloso-marginal artery
A3: from the mouth of the calloso-marginal artery to the upper surface of the corpus callosum 3 cm from his knee
A4: pericallosal segment
A5: terminal branches
middle cerebral artery (MCA)18, segments:
M1: MCA from orifice to bifurcation (on the anterior-posterior AG this is a horizontal segment)
M2: MCA from the fork to the exit from the Sylvius Gap
M3-4: distal branches
M5: terminal branches
Posterior cerebral artery (PCA) (there are several nomenclature schemes for designating its segments, for example, by the names of the cisterns through which they pass19,20):
P1 (peduncle cisterns): ZMA from the mouth to the PCA (other names for this segment: mesencephalic, precommunicant, circular, basilar, etc.).
mesencephalic perforating arteries ( tegmentum, cerebral peduncles, Edinger-Westphal nuclei, III and IV cranial nerves)
interpeduncular long and short thaloperforant arteries (1st of two groups of posterior thaloperforant arteries)
medial posterior choroidal artery (originates from P1 or P2 in most cases)
P2 (enveloping cistern): PCA from the orifice of the PCA to the orifice of the inferior temporal artery (other names for this segment: postcommunicant, perimesencephalic).
lateral (p. 105 - medial) posterior villous artery (in most cases it departs from P2)
thalamo-geniculate thaloperforant arteries (2nd of two groups of posterior thaloperforant arteries) geniculate bodies and pillow
hippocampal artery
anterior temporal (anastomoses with the anterior temporal branch of the MCA)
posterior temporal
leg perforating
parieto-occipital
P3 (four-hilled cistern): PCA from the mouth of the inferior temporal branch to the mouth of the terminal branches.
quadrigeminal and cranked branches quadrigeminal plate
posterior pericallosal artery (artery of the corpus callosum): anastomoses with the pericallosal artery from the ACA
P4: segment after the parietal-occipital and spur arteries originate, includes cortical branches of the PCA
Rice. 3-10. Circle of Willis (view from the base of the brain)
Anterior blood supply
Internal carotid artery (ICA)
Acute blockage of the ICA leads to stroke in 15-20% of cases.
Segments of the ICA and their branches
"Siphon of the ICA": starts from the posterior knee of the cavernous part of the ICA and ends at the fork of the ICA (includes the cavernous, ophthalmic and communicant segments)17
C1 (cervical): originates from the bifurcation of the common carotid artery. Passes along with the internal jugular vein and the vagus nerve in the carotid sheath; postganglionic sympathetic fibers (PSV) cover it. It is located posterior and medial to the external carotid artery. It ends at the entrance to the canal of the carotid artery. Has no branches
C2 (rocky): also surrounded by PGW. It ends at the posterior edge of the torn hole (below and medial to the edge of the Gasser node in the Meckel's sinus). Has 3 segments:
vertical segment: ICA rises up and then bends to form
posterior genu: anterior to cochlea, then curves anterior-medially to form
horizontal segment: located deeper and medial to the greater and lesser petrosal nerves, anterior to the tympanic membrane (TM)
C3 (foramen laceration segment): ICA passes over (rather than through) the laceration to form the lateral genu. It rises in the canalicular portion to the near-sellar position, perforating the DM, passing through the petolingual ligament and becoming a cavernous segment. Branches (usually not visible on AG):
carotic-tympanic branch (non-permanent) tympanic cavity
pterygopalatine (vidian) branch: passes through a torn opening, present in 30% of cases, may continue as an artery of the pterygopalatine canal
C4 (cavernous): Covered by the vascular membrane lining the sinus, still enmeshed in the PSV. Passes anteriorly, then upwards and medially, folds back, forming the medial loop of the ICA, passes horizontally and folds forward (part of the anterior loop of the ICA) to the anterior sphenoid process. It ends at the proximal dural ring (which does not completely cover the ICA). It has many branches, the most important of which are:
meningo-pituitary trunk (largest and most proximal branch):
tentorium artery (artery of Bernasconi and Cassinari)
dorsal meningeal artery
inferior pituitary artery ( posterior pituitary): its occlusion causes pituitary infarcts in postpartum Shehan's syndrome; however, the development of diabetes insipidus is rare, because. the pituitary stalk is preserved)
anterior meningeal artery
artery of the lower part of the cavernous sinus (available in 80%)
McConnell's capsular arteries (present in 30% of cases): supply the pituitary capsule21
C5 (wedge-shaped): ends at the distal dural annulus, which completely surrounds the ICA; after it, the ICA is already intradural
C6 (ophthalmic): originates from the distal dural annulus and ends proximal to the orifice of the PCA
ophthalmic artery (Ophthalmic artery) – in 89% of cases it originates from the ICA distal to the cavernous sinus (intracavernous origin is observed in 8% of cases; OfA is absent in 3% of cases22). Passes through the optic canal into the orbit. On the lateral AG has a characteristic bayonet-like bend
superior pituitary arteries anterior pituitary and stalk (this is the first branch of the supraclinoid part of the ICA)
posterior communicating artery (PCA):
several anterior thalamoperforating arteries ( optic tract, chiasm, and posterior hypothalamus): see Posterior blood supply below)
anterior villous artery: originates 2-4 mm distal to the PCA part of the thalamus, medial parts of the globus pallidus, genu of the internal capsule (IC) (in 50% of cases), lower part of the posterior pedicle of the VC, hook, retrolenticular fibers (crown radiata) ( occlusion syndromes see p.751)
plexus segment: enters the supracornual pocket of the temporal horn only this part of the choroid plexus
C7 (communicant): starts immediately proximal to the orifice of the PCA, passes between the II and III cranial nerves, ends below the anterior perforated substance, where it divides into ACA and MCA
Middle cerebral artery (MCA): branches and angiographic view, see fig. 19-3, p.560.
Anterior cerebral artery (ACA): runs between the II cranial nerve and the anterior perforated substance. Branches and angiographic view see fig. 19-2, p.560.
Blood supply to the back
Angiograms and main branches see fig. 19-5, p.562.
The vertebral artery (VA) is the first and usually main branch of the subclavian artery. In 4% of cases, the left VA may arise directly from the aortic arch. VA has 4 segments:
first: goes up and back and enters the transverse opening, usually the 6th cervical vertebra
second: rises vertically upward through the transverse openings of the cervical vertebrae, accompanied by a network of sympathetic fibers (from the stellate ganglion) and the venous plexus. It turns outward in the transverse process of C2
third: emerges from foramen C2, curves posteriorly and medially in a groove on the superior surface of the atlas, and enters the BZO
fourth: penetrates through the dura and connects with the opposite VA at the level of the lower border of the bridge, forming with it the main artery (OA)
Hypoplasia of the right VA occurs in 10% of cases, the left - in 5% of cases.
Branches of the vertebral artery:
anterior meningeal: arises at body level C2, may be involved in the supply of chords or BZO meningiomas, may be by collateral supply in case of occlusion
posterior meningeal
medullary (bulbar) arteries
posterior spinal artery
posterior inferior cerebellar artery (PICA) - main branch: has 4 segments, 3 branches:
anterior medullary: begins at the inferior border of the olive
lateral medullary (on AG - caudal loop): begins at the lower edge of the medulla oblongata
posterior medullary: goes up in the tonsillo-medullary sulcus
supratonsillar (on AG - cranial loop):
villous artery (1st branch) (choroidal point) choroid plexus of the IVth ventricle
terminal branches:
tonsillo-hemispheric (2nd branch)
artery of the inferior vermis (3rd branch) inferior flexure = copular point
anterior spinal artery
The basilar artery (OA) is formed by the fusion of two vertebral arteries. Her branches:
anterior inferior cerebellar artery (AICA): departs from the lower part of the AA, goes back and laterally in front of the VIth, VIIth and VIIIth CI. Often forms a loop that enters the VSC, where the labyrinth artery departs from it. It supplies blood to the anterolateral sections of the lower part of the cerebellum, and then anastomoses with the PICA
external auditory artery (labyrinth artery)
bridge arteries
superior cerebellar artery (SCA)
superior vermis artery
posterior cerebral artery (PCA): connects to the PCA ≈1 cm from the orifice. Segments and their branches, see p.105
External carotid artery
superior thyroid artery: first anterior branch
ascending pharyngeal artery
lingual artery
facial artery: its branches anastomose with those of OfA (important collateral blood supply)
occipital artery
posterior ear artery
superficial temporal artery
frontal branch
parietal branch
maxillary artery - originally passes inside the parotid salivary gland
middle meningeal artery
accessory sheath artery
inferior alveolar artery
infraorbital artery
others: distal branches that can anastomose with OfA branches in the orbit
The blood supply to the spinal cord (a synonym for spinal circulation (SC) is carried out by the vertebral artery - a branch of the subclavian artery, as well as from the posterior intercostal, lumbar and lateral sacral arteries of the spinal cord: the former spinal artery, unpaired, lying in the anterior longitudinal fissure of the spinal cord, and the paired posterior spinal an artery adjacent to the posterolateral surface of the spinal cord... Numerous branches depart from these arteries and the substance of the brain.
Rice. 5. Scheme of sources of blood supply to the spinal cord
: 1 - aorta; 2 - deep artery of the neck; 3 - anterior radiculomedullary artery of the cervical thickening; 4 - vertebral artery; 5 - intercostal arteries; 6 - upper additional radiculomedullary artery; 7 - large anterior radiculomedullary artery (Adamkevich's artery); 8 - lower additional radiculomedullary artery; 9 - iliac-lumbar artery; dashed lines indicate the boundaries of parts of the spinal cord (I - cervical, II - thoracic, III - lumbar, IV - sacral).
It has been established that several upper cervical segments of the spinal cord supply blood to the anterior and posterior spinal arteries, which branch off from the vertebral arteries. The segments below segments CIII-CIV receive blood from the radiculomedullary arteries. Each such artery, approaching the surface of the spinal cord, dichotomously divides into ascending and descending branches, which connect with similar branches above and below the located radiculomedullary arteries and form the anterior and two posterior arterial anastomotic tracts along the spinal cord (anterior and posterior spinal arteries).
Rice. 6 Schematic representation of the blood supply to a segment of the spinal cord (cross section):
dots indicate the peripheral arterial zone, oblique shading - the central arterial zone, horizontal shading - the area of blood supply to the posterior spinal artery; 1 - area of overlap of the central arterial zone and the zone of blood supply of the posterior spinal artery; 2 - submersible branches; 3 - anterior spinal artery; 4 - posterior spinal artery.
Along the anastomotic tracts, there are areas with oppositely directed blood flow, in particular, in the places where the main trunk of the radiculomedullary artery divides into ascending and descending branches. The number of radiculomedullary arteries includes from 2 to 27 (usually 4-8) anterior arteries and from 6 to 28 (usually 15-20) posterior. There are two extreme types of structure of the vessels supplying the spinal cord - main and loose. With the main type, there is a small number of radiculomedullary arteries (3-5 anterior and 6-8 posterior). With a loose type, there are more such arteries (6-12 anterior and 22 or more posterior). The largest anterior radiculomedullary arteries are located in the mid-cervical region of the spinal cord (cervical enlargement artery) and in the lower thoracic or upper lumbar region (lumbar enlargement artery, or the large anterior radiculomedullary artery of Adamkevich). The Adamkevich artery enters the spinal canal next to one of the spinal roots, usually on the left. In 15-16% of cases, there is a large anterior radiculomedullary artery that accompanies the LV or SI root and an inferior accessory radiculomedullary artery that supplies the segments of the epicone and cone of the spinal cord.
The sources of the radiculomedullary arteries at the level of the neck are the deep arteries of the neck (less often the vertebral arteries), at the level of the thoracic region - the posterior intercostal arteries, at the level of the lumbar - the lumbar arteries, at the level of the sacrum - the lateral sacral and iliac-lumbar arteries. The anterior radiculomedullary arteries supply blood to the anterior (ventral) 4/5 of the diameter of the spinal cord, and the branches of the posterior radiculomedullary arteries supply the posterior part of the diameter.
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The circulatory system of the spinal cord divided along the length and along the diameter.
The blood supply system of the spinal cord along the length
The blood supply to the spinal cord is provided by the anterior and paired posterior spinal arteries, as well as the radicular-spinal arteries.Located on the anterior surface of the spinal cord, the anterior artery begins from two vertebral arteries and branches extending from the intracranial part, called spinal, which soon merge and form a common trunk that goes down along the anterior sulcus of the ventral surface of the spinal cord.
The two posterior spinal arteries, originating from the vertebral arteries, run along the dorsal surface of the spinal cord directly at the posterior roots; each artery consists of two parallel stems, one of which is located medially, and the other is lateral to the posterior roots.
The spinal arteries originating from the vertebral arteries supply blood to only 2-3 upper cervical segments, while the rest of the spinal cord is nourished by the radicular-spinal arteries, which in the cervical and upper thoracic regions receive blood from the branches of the vertebral and ascending cervical arteries (the subclavian system). arteries), and below - from the intercostal and lumbar arteries extending from the aorta.
The dorso-spinal artery departs from the intercostal artery and divides into the anterior and posterior radicular-spinal arteries. The anterior and posterior radicular-spinal arteries, passing through the intervertebral foramen, go along with the nerve roots. Blood from the anterior radicular arteries enters the anterior spinal artery, and from the posterior - to the posterior spinal.
The anterior radicular arteries are smaller than the posterior ones, but they are larger. The number of arteries varies from 4 to 14 (usually 5-8). In the cervical region, in most cases, there are 3. The upper and middle parts of the thoracic spinal cord (from ThIII to ThVII) are fed by 2-3 thin radicular arteries. The lower thoracic, lumbar and sacral parts of the spinal cord are supplied by 1-3 arteries. The largest of them (2 mm in diameter) is called the artery of the lumbar thickening or the artery of Adamkevich.
Switching off the artery of the lumbar thickening gives a characteristic clinical picture of spinal cord infarction with severe symptoms.
Starting from the 10th, and sometimes from the 6th thoracic segment, it nourishes the entire lower part of the spinal cord. Adamkevich's artery enters the spinal canal usually with one of the roots from ThVIII to LIV, more often with ThX, ThXI or ThXII thoracic root, in 75% of cases - on the left and in 25% - on the right.
In some cases, in addition to Adamkevich's artery, small arteries are found that enter from the ThVII, ThVIII or ThIX root, and an artery that enters from the LV lumbar or SI sacral root, supplying the cone and epicone of the spinal cord. This is the Desproges-Gotteron artery. There are about 20 posterior radicular arteries; they are of smaller caliber than the front ones.
Thus, there are three critical levels of blood supply to the spinal cord along the length: ThII-ThIII; ThVIII-ThX; LIV-SI.
The supply system of the spinal cord along the diameter
A large number of central arteries (a.a. centralis) depart from the previous spinal artery at a right angle, which pass along the anterior spinal sulcus and, near the anterior gray commissure, enter the substance of the spinal cord either in the right or in its left half. The central arteries supply the anterior horns, the base of the posterior horns, Clark's columns, the anterior columns, and most of the lateral columns of the spinal cord.Thus, the anterior spinal artery supplies approximately 4/5 of the diameter of the spinal cord. The branches of the posterior spinal arteries enter the region of the posterior horns and, in addition to them, feed almost entirely the posterior columns and a small part of the lateral columns. Thus, the posterior spinal artery supplies approximately 1/5 of the diameter of the spinal cord.
Both posterior spinal arteries are connected to each other and to the anterior spinal artery with the help of horizontal arterial trunks that run along the surface of the spinal cord and form a vascular ring around it - Vasa corona.
Perpendicular to this ring are multiple trunks that enter the spinal cord. Inside the spinal cord, between the vessels of neighboring segments, as well as between the vessels of the right and left sides, there are abundant anastomoses from which a capillary network is formed, denser in the gray matter than in the white.
The spinal cord has a highly developed venous system.
The veins that drain the anterior and posterior sections of the spinal cord have a watershed approximately in the same place as the arteries. The main venous channels, which receive the blood of the veins from the substance of the spinal cord, run in the longitudinal direction, similarly to the arterial trunks. At the top, they connect with the veins of the base of the skull, forming a continuous venous tract. The veins of the spinal cord also have a connection with the venous plexuses of the spine, and through them - with the veins of the body cavities.
Vertebrogenic vascular myeloischemia
Most often, myeloischemia of vertebral origin is caused by osteochondrosis of the cervical and lumbar spine. Spinal vascular disorders can occur both acutely, stroke-like (for example, with a prolapse of the disc), and gradually, chronically (with the "growth" of posterior exostoses, hypertrophy of the yellow ligament and gradual compression of the vessels).Often, vascular pathology is manifested by transient disorders of the spinal circulation, their mechanism is usually reflex. In the pathogenesis of vascular myeloischemia, a particularly important role is played by a decrease in the size of the intervertebral foramina through which the radiculomedullary arteries pass. With osteochondrosis, the discs flatten, settle, which in itself leads to a narrowing of the intervertebral foramen.
Contribute to vascular compression "looseness" of the vertebra, pathological mobility, instability (pseudospondylolisthesis), which is a consequence of weakening the fixation of the ligamentous apparatus of the spine, especially in cervical osteochondrosis. The concomitant reactive growths of bone and cartilage tissue with the formation of osteophytes and neoarthroses make these openings even narrower.
Any movement in the affected area (and even if it is not fixed enough), which entails even a minimal narrowing of the intervertebral foramen, increases the compression of the vessels and roots passing through here.
In addition to the direct effect on the vessel with its compression and impaired blood flow, as a rule, there is also a reflex component - narrowing of the arteries occurs due to irritation in a narrow bed. This also manifests itself as a transient vascular inferiority. The radiculomedullary arteries and veins are compressed most often when the lower lumbar discs prolapse.
Thus, in vertebrogenic vascular myeloischemia, medullary pathology depends on the state of the main process - the vertebral one. Vascular pathology in these cases must be assessed taking into account the root cause of suffering - the pathology of the spine. An approach from such positions to this complex suffering will provide adequate pathogenetic therapy.
Damage to the radiculomedullary arteries of the cervical thickening
The disease usually develops acutely after injuries with hyperextension of the head (for example, with a "diver's injury"). Segmental motor and conduction sensory disturbances, disorders of the function of the pelvic organs develop. Loss of consciousness is not always observed. Movement disorders can be of varying severity: from mild paresis to complete tetraplegia.Predominantly superficial types of sensitivity suffer. In most cases, there is a good regression of symptoms. Residual effects of the disease are manifested mainly by peripheral paresis of the distal parts of the arm and light pyramidal signs on the legs. The syndrome of amyotrophic lateral sclerosis can also develop in chronic decompensation of the spinal circulation in the cervical segments.
Damage to the large anterior radiculomedullary artery of Adamkevich
The development of the clinical picture depends on the territory of the spinal cord supplied by this artery in a given patient, on the presence or absence of additional radicular arteries (Desproges-Gotteron arteries), the upper or lower additional radiculomedullary artery.Transient circulatory disorders in this artery have their own characteristics - the syndrome of "intermittent claudication" of the spinal cord (myelogenous intermittent claudication syndrome), sensations of heaviness, weakness in the legs, paresthesia that spread to the perineum, lower body, imperative urge to urinate develop.
All this quickly disappears with rest. Such patients do not have pain in the legs and weakening of the pulsation of peripheral vessels - pathognomonic signs of peripheral intermittent claudication (Charcot's disease). The most important distinguishing feature is the presence in the anamnesis of indications of recurrent pain in the lower back. An objective examination, as a rule, reveals a vertebral syndrome.
Compression of Adamkevich's artery usually develops after heavy lifting, long shaking driving, awkward movement. Acutely develops lower paraparesis, up to plegia. The paralysis is flaccid. First, there are features of flaccid paralysis, then symptoms of spastic paralysis may join. Superficial types of sensitivity according to the conductive type are violated, occasionally in the acute stage, deep sensitivity also decreases.
Disorders of the function of the pelvic organs of the central or peripheral type are characteristic. Trophic disorders in the form of bedsores join early. Hypotrophy of the leg muscles develops rapidly. Regression of symptoms is observed slowly, dysfunctions of sphincters of pelvic organs are especially stable.
Damage to the inferior accessory radiculomedullary artery of Desproges-Gotteron
Transient circulatory disorders in the pool of this artery occur as myelogenous or as causogenic intermittent claudication (Verbiest's syndrome). When walking, painful paresthesias appear in the legs, spreading to the perineal region. Then the pain in the legs joins. These complaints are especially frequent in persons with narrowness of the spinal canal.With compression of an additional artery that goes with the LV or SI roots, a syndrome of spinal cord injury develops, of varying severity: from mild paralysis of individual muscles to severe epiconus syndrome with anesthesia in the anogenital region, gross pelvic and motor disorders - the syndrome of the so-called paralyzing sciatica (de Sez et al.).
Usually, against the background of a long-term radicular syndrome or the phenomena of caudogenic intermittent claudication, paralysis of the muscles of the lower leg and buttocks occurs. The peroneal muscle group suffers more often (the patient cannot stand and walk on his heels), less often the tibial group (he cannot stand and walk on his toes); the foot hangs or, on the contrary, takes the form of a calcaneal foot. Hypotonia covers the muscles of the lower leg, thigh, buttocks. Achilles reflexes may be lost or retained.
Fascicular twitching of the leg muscles is often observed. Characteristic is the development of paresis in symmetrical myotomes (LIV, LV, SI, SII), which occurs after the disappearance of radicular pain. Sensory disturbances develop in the anogenital region. In this way, the dynamics and nature of the process differ from compression radiculomyelopathies with their asymmetry of the lesion and the stability of radicular pain.
Therefore, there are two mechanisms of damage to the roots with the development of paresis of the muscles of the leg: compression radiculopathy and compression-ischemic radiculopathy.
At the same time, according to A. A. Skoromets and Z. A. Grigoryan, the syndrome of paralysis of myotomes 1-2 can occur from ischemia only of the root or in combination with ischemia and the corresponding segments of the spinal cord. With the radicular variant of paralyzing sciatica, the pathological process is one-sided.
With compression-vascular radiculo-ischemia, the symptoms of spinal cord injury with segmental and conduction disturbances of sensitivity clearly appear. Paresis covers a wider area. Often there are bilateral pathological foot signs, even with the loss of Achilles reflexes.
Posterior spinal artery injury
Ischemic disorders in the basin of the posterior spinal arteries often develop in the cervical spinal cord, less often in the thoracic, and even less often in the lumbar. The leading symptoms of an isolated lesion of the posterior spinal artery are sensory disorders. All kinds of sensibility suffer. There are segmental disturbances of sensitivity, procrioceptive reflexes fall out due to damage to the posterior horn.Sensitive ataxia develops due to a violation of the joint-muscular feeling. Signs of damage to the pyramidal tracts are revealed. With damage to the posterior spinal arteries at the level of the cervical segments, due to the peculiarity of the vascularization of the Gaulle and Burdach bundles, a peculiar symptom complex develops.
Clinically, it is characterized by a loss of deep sensation in the arms with sensitive ataxia, while maintaining deep sensation in the legs. This is combined with spastic spinal hemiparesis, sometimes with segmental sensory disturbances.
Circulatory disorders in various vascular pools of the spinal cord lead to ischemia of different zones both in original and in diameter. In some cases, only the gray matter is affected, in others - gray and white. Ischemia can spread to one or both halves of the spinal cord, along the length - to one or two segments or a whole section of the spinal cord.
In each individual case, the localization of the lesion determines the development of certain clinical symptoms. The most common combinations of symptoms of the lesion are combined into separate compression-vascular syndromes.
THEM. Danilov, V.N. Naboychenko
The spinal cord is supplied with blood by the anterior spinal artery (a. spinalis anterior), which runs along the anterior median groove of the spinal cord, and twoposterior spinal arteries (aa. spinales posteriores), located on the lateral surfacespinal cord. Both the anterior and posterior spinal arteries originate from a. verte oralis still in the cranial cavity, and below the segments C III - C IV they are formed by separate radiculomedullary arteries extending from the intercostal, lumbar and sacral arteries - branches of the aorta (Fig. 31, 32).
They enter the spinal canal through the foramen inter-vertebrale along with the roots of the spinal cord. There are 64 radicular arteries in total, but usually 3-5 of them play the main role in the blood supply to the spinal cord, most often the upper (Th IV - Th V) and lower (Li IV - L v) additional and large anterior radiculomedullary artery of Adamkevich (Th x — ThxII).
The basin of the anterior spinal artery vascularizes approximately 4/5 of the diameter of the spinal cord - the anterior horns, anterior and lateral columns, etc., the posterior spinal arteries 4 - only the posterior columns and the posterior sections of the posterior horns. On the surface of the spinal cord, the anterior and posterior spinal arteries, as well as the radicular arteries, are connected by anastomoses, forming a vascular crown (vasocorona), the branches of which penetrate the white matter, anterior and posterior horns.
The outflow of blood from the spinal cord is carried out through the system of superficial and deep spinal veins and the internal and external venous plexuses. Further, through the anterior and building, the radicular and intercostal veins flow mainly into the inferior vena cava (v. cava inferior).
The mechanism of regulation of cerebral circulation is neurohumoral.
The nervous mechanism presupposes the presence of a special apparatus: vascular receptors, regulatory centers, afferent and efferent pathways for the transmission of nerve influences onvessels. The receptor apparatus is represented by baro-, tenso-and chemoreceptors. The pressor vasomotor center, which increases sympathetic activity and secretion of catecholamines by the adrenal glands, is localized in the lateral parts of the reticular formation of the brainstem, and the degressor center, which inhibits sympathetic activity, is located in the medial part of the reticular formation of the brainstem.
The cerebral vessels constrict under the influence of sympathetic innervation and catecholamines, as well as with a lack of carbon dioxide or an excess of oxygen, and expand under the action of parasympathetic impulses, an excess of carbon dioxide, or a lack of oxygen. Stimulation of the sympathetic nodes in the neck significantly reduces cerebral blood flow (by 20-30%).
The combination of nervous and humoral regulation ensures the constancy of cerebral blood flow even with sharp fluctuations in total blood pressure. Cerebral blood flow remains constant with changes in blood pressure within the range of systolic pressure fluctuations from 60 to 220 mm Hg. Art. Only in the case of a decrease in pressure below 60 mm Hg. Art. it decreases, with an increase in blood pressure more than 220 mm Hg. Art. it increases due to passive vasodilation.
An important factor in the uninterrupted supply of oxygen and glucose to the brain and spinal cord is the greater stability of the blood flow velocity in the capillaries of the brain, where it is 4-5 cm per 1 min. Any change in it in the direction of increasing or decreasing leads to brain hypoxia.
Article on the topic of blood supply to the spinal cord
