cerebellum, part of the brain located under the occipital lobes hemispheres. Its purpose is to regulate muscle tone, maintain balance and coordinate movements. Scientific and technical dictionary
8.1. Blood supply to the brain
The blood supply to the brain is provided by two arterial systems: the internal carotid arteries (carotid) and the vertebral arteries (Fig. 8.1).
Vertebral arteries originate from the subclavian arteries, enter the canal of the transverse processes of the cervical vertebrae, at the level of the I cervical vertebra (C\) leave this canal and penetrate through the foramen magnum into the cranial cavity. When it changes cervical spine, the presence of osteophytes, compression is possible vertebral artery PA at this level. In the cranial cavity, PAs are located at the base of the medulla oblongata. At the border of the medulla oblongata and the pons of the brain, the PA merge into a common trunk of a large basilar artery. At the anterior edge of the bridge, the basilar artery divides into 2 posterior cerebral arteries.
internal carotid artery is a branch general carotid artery, which on the left departs directly from the aorta, and on the right - from the right subclavian artery. In connection with this arrangement of vessels in the system of the left carotid artery, optimal conditions for blood flow are maintained. At the same time, when a thrombus ruptures from the left region of the heart, the embolus much more often enters the branches of the left carotid artery ( direct message with the aorta) than in the system of the right carotid artery. The internal carotid artery enters the cranial cavity through the canal of the same name.
Rice. 8.1.The main arteries of the brain:
1 - aortic arch; 2 - brachiocephalic trunk; 3 - left subclavian artery; 4 - right common carotid artery; 5 - vertebral artery; 6 - external carotid artery; 7 - internal carotid artery; 8 - basilar artery; 9 - ophthalmic artery
(Can. caroticus),from which it emerges on both sides of the Turkish saddle and the optic chiasm. The terminal branches of the internal carotid artery are middle cerebral artery, running along the lateral (Sylvian) groove between the parietal, frontal and temporal lobes, and anterior cerebral artery(Fig. 8.2).
Rice. 8.2.Arteries of the outer and inner surfaces of the cerebral hemispheres:
A- outer surface: 1 - anterior parietal artery (branch of the middle cerebral artery); 2 - posterior parietal artery (branch of the middle cerebral artery); 3 - artery of the angular gyrus (branch of the middle cerebral artery); 4 - the final part of the posterior cerebral artery; 5 - posterior temporal artery (branch of the middle cerebral artery); 6 - intermediate temporal artery (branch of the middle cerebral artery); 7 - anterior temporal artery (branch of the middle cerebral artery); 8 - internal carotid artery; 9 - left anterior cerebral artery; 10 - left middle cerebral artery; eleven - terminal branch anterior cerebral artery; 12 - lateral ophthalmic-frontal branch of the middle cerebral artery; 13 - frontal branch of the middle cerebral artery; 14 - artery of the precentral gyrus; 15 - artery of the central sulcus;
b- inner surface: 1 - pericallosal artery (branch of the middle cerebral artery); 2 - paracentral artery (branch of the anterior cerebral artery); 3 - preclinical artery (branch of the anterior cerebral artery); 4 - right posterior cerebral artery; 5 - parieto-occipital branch of the posterior cerebral artery; 6 - spur branch of the posterior cerebral artery; 7 - posterior temporal branch of the posterior cerebral artery; 8 - anterior temporal branch of the cerebral artery; 9 - posterior communicating artery; 10 - internal carotid artery; 11 - left anterior cerebral artery; 12 - recurrent artery (branch of the anterior cerebral artery); 13 - anterior communicating artery; 14 - ophthalmic branches of the anterior cerebral artery; 15 - right anterior cerebral artery; 16 - branch of the anterior cerebral artery to the pole of the frontal lobe; 17 - corpus callosum artery (branch of the anterior cerebral artery); 18 - medial frontal branches of the anterior cerebral artery
The connection of two arterial systems (internal carotid and vertebral arteries) is carried out due to the presence of cerebral arterial circle(the so-called circle of Willis). The two anterior cerebral arteries are anastomosed with anterior communicating artery. The two middle cerebral arteries anastomose with the posterior cerebral arteries with posterior communicating arteries(each of which is a branch of the middle cerebral artery).
Thus, the arterial circle of the cerebrum is formed by arteries (Fig. 8.3):
Posterior cerebral (system of vertebral arteries);
Posterior communicating (system of the internal carotid artery);
Middle cerebral (system of the internal carotid artery);
Anterior cerebral (system of the internal carotid artery);
Anterior connective (system of the internal carotid artery).
The function of the circle of Willis is to maintain adequate blood flow in the brain: if blood flow is disturbed in one of the arteries, compensation occurs due to the system of anastomoses.
Anterior cerebral artery blood supply (Fig. 8.4):
The cerebral cortex and subcortical white matter of the medial surface of the frontal and parietal lobes of the lower (basal) surface of the frontal lobe;
Rice. 8.3.Arteries of the base of the brain:
1 - anterior communicating artery;
2 - recurrent artery (branch of the anterior cerebral artery); 3 - internal carotid artery; 4 - anterior cerebral artery; 5 - middle cerebral artery; 6 - anterolateral thalamostriatal arteries; 7 - anterior villous artery; 8 - posterior communicating artery; 9 - posterior cerebral artery; 10 - superior cerebellar artery; 11 - main artery; 12 - artery of the labyrinth; 13 - anterior inferior cerebellar artery; 14 - vertebral artery; 15 - anterior spinal artery; 16 - posterior inferior cerebellar artery; 17 - posterior spinal artery
Upper sections of the precentral and postcentral gyri;
Olfactory tract;
Anterior 4/5 of the corpus callosum;
Head and outer part of the caudate nucleus;
Anterior sections of the lenticular (lenticular) nucleus;
Anterior leg of the internal capsule.
Rice. 8.4.Blood supply to the cerebral hemispheres and brain stem:
A)I - frontal cut at the level of the most pronounced basal nuclei,
II - frontal section at the level of the nuclei of the thalamus. The pool of the middle cerebral artery is marked in red, the anterior cerebral artery in blue, the posterior cerebral artery in green, and the anterior choroidal artery in yellow;
b)pools: 1 - posterior cerebral artery; 2 - superior cerebellar artery; 3 - paramedian arteries (from the main artery); 4 - posterior inferior cerebellar artery; 5 - anterior spinal artery and paramedian arteries (from the vertebral artery); 6 - anterior inferior cerebellar artery; 7 - posterior spinal artery
The cortical branches of the anterior cerebral artery descend along the outer surface of the hemispheres, anastomosing with the branches of the middle cerebral artery. Thus, the middle part of the precentral and postcentral gyri (projection of the arms) is vascularized from two basins at once.
Middle cerebral artery provides blood supply (Fig. 8.4):
cerebral cortex and subcortical white matter most of the outer surface of the cerebral hemispheres;
Knee and anterior 2 / 3 hind legs of internal capsule;
Parts of the caudate and lenticular nuclei;
Visual radiance (graziola beam);
Wernicke's center of the temporal lobe;
parietal lobe;
Middle and inferior frontal gyri;
Posterior inferior part of the frontal lobe;
Central slice.
At the base of the brain, the middle cerebral artery gives off several deep branches that immediately penetrate into the substance of the brain and vascularize the knee and the anterior 2/3 of the posterior leg of the internal capsule, part of the caudate and lenticular nuclei. One of the deep branches - the artery of the lentiform nucleus and the striatum, belonging to the system of thalamostriatal arteries, is one of the main sources of hemorrhage in basal nuclei and an inner capsule.
Another branch - anterior choroidal artery often departs directly from the internal carotid artery and provides vascular plexus vascularization, and can also take part in the blood supply to the caudate and lenticular nuclei, the motor zone of the internal capsule, visual radiation (Graziole's bundle), Wernicke's center of the temporal lobe.
In the lateral groove, several arteries depart from the middle cerebral artery. The anterior, intermediate and posterior temporal arteries vascularize the temporal lobe, the anterior and posterior parietal arteries provide nutrition to the parietal lobe, a wide common trunk is sent to the frontal lobe, which splits into the orbital-frontal branch (vascularizes the middle and inferior frontal gyrus), the artery of the precentral sulcus (posterior- lower part of the frontal lobe) and the artery of the central sulcus (supplies the central lobule).
The middle cerebral artery vascularizes not only the cerebral cortex, but also a significant part of the white matter, including under
bark of the upper part of the central lobule, related to the basin of the anterior cerebral artery, and the internal capsule. Therefore, blockage of the deep central branch of the middle cerebral artery causes uniform hemiplegia with damage to the face, and arms, and legs, and the defeat of the superficial precentral branch - uneven hemiparesis with a predominant lesion of the muscles of the face and arm. Posterior cerebral artery vascularizes:
The cerebral cortex and subcortical white matter of the occipital lobe, posterior parietal lobe, lower and posterior parts of the temporal lobe;
Posterior parts of the thalamus;
Hypothalamus;
corpus callosum;
Caudate nucleus;
Part of the visual radiance (graziola beam);
Subthalamic nucleus (Lewis body);
quadrigemina;
Legs of the brain.
The blood supply to the brainstem and cerebellum is provided by the vertebral arteries, basilar and posterior cerebral arteries (Fig. 8.5, 8.6).
Basilar artery (the so-called main) takes part in the vascularization of the brain bridge and cerebellum. The blood supply to the cerebellum is carried out by three pairs of cerebellar arteries, two of which depart from the main artery (superior and anterior inferior), and one (posterior inferior) is the largest branch of the vertebral artery.
Vertebral arteries form the basilar artery, give off two branches that merge into the anterior spinal artery, two posterior spinal arteries that do not merge and run separately along the sides of the posterior cords of the spinal cord, and also two posterior inferior cerebellar arteries. The vertebral arteries vascularize:
Medulla;
Posterior-lower cerebellum;
Upper segments of the spinal cord.
Posterior inferior cerebellar artery vascularizes:
Upper lateral sections of the medulla oblongata (rope bodies, vestibular nuclei, trigeminal superficial sensory nucleus, double nucleus of the trunk of the spinothalamic pathway);
Posterior part of the cerebellum.
Rice. 8.5.Arteries of the vertebrobasilar system:
A- main segments of the vertebral artery (V1-V4): 1 - subclavian artery; 2 - common carotid artery; 3 - external carotid artery; 4 - main artery; 5 - posterior cerebral artery; 6 - occipital artery; b- blood supply to the brain stem and cerebellum: 7 - main artery, bridge branches; 8 - internal carotid artery; 9 - posterior communicating artery; 10 - middle cerebral artery; 11 - anterior cerebral artery; 12 - shell; 13 - inner capsule; 14 - caudate nucleus; 15 - thalamus; 16 - posterior cerebral artery; 17 - superior cerebellar artery; 18 - labyrinth artery;
V- cross section of the bridge; blood supply: 19 - main artery; 20 - medial branches; 21 - mediolateral branches; 22 - lateral branches
Rice. 8.6.Vessels of the base of the brain (scheme):
1 - cerebral part of the internal carotid artery; 2 - middle cerebral artery; 3 - anterior cerebral artery; 4 - anterior communicating artery; 5 - posterior communicating artery; 6 - posterior cerebral artery; 7 - main artery; 8 - superior cerebellar artery; 9 - anterior inferior cerebellar artery; 10 - posterior inferior cerebellar artery; 11 - vertebral artery
A characteristic difference in the blood supply to the brain is the absence of the usual "gateway" system. The branches of the arterial circle of the cerebrum do not enter the medulla (as is observed in the liver, lungs, kidneys, spleen and other organs), but spread over the surface of the brain, successively giving off numerous thin branches extending at right angles. Such a structure, on the one hand, provides a uniform distribution of blood flow over the entire surface of the cerebral hemispheres, and on the other hand, creates optimal conditions for vascularization for the cerebral cortex. This also explains the absence of large-caliber vessels in the substance of the brain - small arteries, arterioles, and capillaries predominate. The most extensive network of capillaries is found in the hypothalamus and in the subcortical white matter.
Large cerebral arteries on the surface of the brain pass in the thickness arachnoid, between
its parietal and visceral layers. The position of these arteries is fixed: they are suspended on the trabeculae of the arachnoid and, in addition, are supported by their branches at a certain distance from the brain. Displacement of the brain relative to the membranes (for example, with a head injury) leads to the development of subarachnoid hemorrhage due to stretching and tearing of the "connecting" branches.
Between vascular wall and brain tissue there are intracerebral perivascular spaces of Virchow-Robin, which
Rice. 8.7.Veins of the face and dura:
I - superior sagittal sinus; 2 - lower sagittal sinus; 3 - a large cerebral vein; 4 - transverse sinus; 5 - direct sine; 6 - upper and lower stony sinuses; 7 - internal jugular vein; 8 - retromaxillary vein; 9 - pterygoid venous plexus; 10 - facial vein;
II - inferior ophthalmic vein; 12 - superior ophthalmic vein; 13 - intercavernous sinuses; 14 - cavernous sinus; 15 - parietal graduate; 16 - crescent of the brain; 17 - superior cerebral veins
communicate with the subarachnoid space and are intracerebral cerebrospinal fluid pathways. Blockage of the orifice of the Virchow-Robin space (at the entry points to the brain vessels) disrupts the normal circulation of the cerebrospinal fluid and can lead to the occurrence of intracranial hypertension (Fig. 8.7).
The intracerebral capillary system has a number of features:
Brain capillaries do not have Roger cells that have contractile ability;
The capillaries are surrounded only by a thin elastic membrane, inextensible under physiological conditions;
The functions of transudation and absorption are performed by precapillaries and postcapillaries, and the differences in blood flow velocity and intravascular pressure create conditions for fluid transudation in the precapillary, and for absorption in the postcapillary.
Thus, the complicated system precapillary - capillary - postcapillary ensures the balance of the processes of transudation and absorption without the help of the lymphatic system.
Syndromes of defeat of separate vascular pools. When blood flow is disturbed in the anterior cerebral artery, the following are observed:
Irregular contralateral hemiparesis and contralateral hemihypesthesia predominantly affecting the leg
(upper section of the central lobule) on the side opposite to the focus. Paresis of the hand recovers faster, with the classic version, monoparesis and monohypesthesia of the lower limb are noted;
On a paralyzed leg, mild sensory disturbances may be noted;
Grasping and axial reflexes contralateral to the focus (subcortical automatisms are disinhibited);
Homolateral hemiataxia (impaired cortical correction of movements along the fronto-pontocerebellar pathway);
Homolateral apraxia (cortical zones of praxis and corpus callosum), with monoparesis of the leg, apraxia of the arm on the same side can be detected;
Change in the psyche - the so-called frontal psyche (apatoabulic, disinhibited-euphoric or mixed variants);
Hyperkinesis of the muscles of the face and arm (lesion of the anterior part of the caudate and lenticular nuclei) homolaterally;
Violation of the sense of smell (olfactory tract) homolateral;
Disorder of urination according to the central type with bilateral lesions.
middle cerebral artery the following symptoms are observed:
Hemiplegia/hemiparesis contralateral to the focus (uniform with damage to the deep branches of the middle cerebral artery and uneven with blockage of the cortical branches);
Contralateral focus hemianesthesia/hemihypesthesia;
Oppression of consciousness;
Turning the head and gaze towards the focus (damage to the adversive field);
Motor aphasia (Broca's center of the frontal lobe), sensory aphasia (Wernicke's center of the temporal lobe) or total aphasia;
Bilateral apraxia (with damage to the lower pole of the left parietal lobe);
Violation of stereognosis, anosognosia, violation of the body scheme ( upper divisions right parietal lobe);
Contralateral hemianopia.
When blocked anterior choroidal artery develops clinical syndrome in the form of hemiplegia, hemianesthesia, hemianopsia,
thalamic pain, gross vasomotor disorders with swelling of the affected limbs.
In case of circulatory disorders in the pool posterior cerebral artery arise:
Contralateral homonymous hemianopsia, half or quadrant (damage to the inner surface of the occipital lobe, spur groove of the wedge, lingual groove);
Visual agnosia (outer surface of the left occipital lobe);
Thalamic syndrome: hemianesthesia contralateral to the focus, hemiataxia, hemianopsia, thalamic pain, trophic and emotional disorders, and pathological limb settings (eg, thalamic arm);
Amnestic aphasia, alexia (damage to adjacent areas of the parietal, temporal and occipital lobes on the left);
Athetoid, choreiform hyperkinesis homolaterally;
Alternating syndromes of damage to the midbrain (Weber and Benedict syndromes);
nystagmus;
Symptom of Hertwig-Magendie;
Peripheral hemianopsia caused by damage to the posterior parts of the visual tracts (complete half homonymous hemianopsia on the opposite side with loss of pupillary reaction from the "blind" halves of the retinas);
Korsakov's syndrome;
Autonomic disorders, sleep disorders. Acute blockage basilar artery calls:
Paralysis of the limbs (hemi-, tetraplegia);
Sensitivity disorders on one or both sides of the conductive type;
Defeat cranial nerves(II, III, V, VII), more often in the form of alternating stem syndromes, often there is a divergence of optical axes eyeballs horizontally or vertically (dysfunction of the medial longitudinal bundle);
Changes in muscle tone (hypotension, hypertension, decerebrate rigidity, hormetonia);
Pseudobulbar paralysis;
Respiratory disorders.
Gradual blockage basilar artery (thrombosis) is characterized by a slow deployment of the clinical picture. At the beginning
transient symptoms appear: dizziness, staggering when walking, nystagmus, paresis and hypoesthesia of the extremities, facial asymmetry, oculomotor disorders.
In case of circulatory disorders in the pool vertebral artery arise:
Occipital headache, dizziness, noise, ringing in the ears, nystagmus, photopsia, a feeling of "fog" before the eyes;
Respiratory and cardiovascular disorders;
Contralateral hemiplegia and hemianesthesia of the trunk and extremities;
Homolateral violation of superficial sensitivity on the face;
Bulbar syndrome;
Radicular syndrome at the cervical level.
There may be an alternating Wallenberg-Zakharchenko syndrome, characteristic of blockage of the posterior inferior cerebellar artery.
When defeated posterior inferior cerebellar artery observed:
dizziness, nausea, vomiting, hiccups;
Homolateral violation of surface sensitivity on the face (damage to the spinal tract of the Vth nerve), decreased corneal reflex;
Homolateral bulbar paresis: hoarseness, swallowing disorders, decreased pharyngeal reflex;
Violation of the sympathetic innervation of the eye - Bernard-Horner syndrome (damage to the descending fibers to the ciliospinal center) on the side of the lesion;
Cerebellar ataxia;
Nystagmus when looking towards the lesion;
Contralateral mild hemiparesis (damage to the pyramidal tract);
Pain and temperature hemianesthesia on the trunk and extremities (spinothalamic pathway) contralateral to the focus.
8.2. Venous outflow
Outflow of blood from the brain carried out through the system of superficial and deep cerebral veins, which flow into the venous sinuses of the dura mater (Fig. 8.7).
Superficial cerebral veins - upper And lower- collect blood from the cerebral cortex and subcortical white matter. The upper ones flow into the superior sagittal sinus, the lower ones -
into the transverse sinus and other sinuses of the base of the skull. Deep veins provide outflow of blood from the subcortical nuclei, the internal capsule, the ventricles of the brain and merge into one great cerebral vein which flows into the direct sinus. The veins of the cerebellum drain into the great cerebral vein and the sinuses of the base of the skull.
From the venous sinuses, blood flows through the internal jugular veins, vertebral veins, then through the brachiocephalic veins and flows into the superior vena cava. In addition, to ensure the outflow of blood, diploic veins of the skull And emissive veins, connecting the sinuses with the external veins of the skull, as well as small veins emerging from the skull along with the cranial nerves.
Characteristic features of the veins of the brain are lack of valves And many anastomoses. An extensive venous network of the brain, wide sinuses provide optimal conditions for the outflow of blood from a closed cranial cavity. Venous pressure in the cranial cavity is almost equal to intracranial pressure. This is due to the increase intracranial pressure with venous stasis and, conversely, impaired venous outflow in intracranial hypertension (tumors, hematoma, hyperproduction of cerebrospinal fluid, etc.).
Venous sinus system has 21 sinuses (8 paired and 5 unpaired). The walls of the sinuses are formed by sheets of processes of the dura mater. On the cut, the sinuses have a fairly wide triangular lumen. The largest is superior sagittal sinus. He goes to the top sickle brain, receives blood from superficial cerebral veins and is widely associated with diploic and emissary veins. In the lower part of the falx cerebrum is located inferior sagittal sinus, anastomosing with the superior sagittal sinus using the veins of the falx cerebrum. Both sagittal sinuses are associated with straight sinus, located at the junction of the falx cerebrum and the cerebellum. In front, a large cerebral vein flows into the straight sinus, carrying blood from the deep parts of the brain. The continuation of the superior sagittal sinus under the cerebellar tenon is occipital sinus, leading to the foramen magnum. At the point of attachment of the cerebellar mantle to the skull, there is a paired transverse sinus. All of these sinuses are connected in one place, forming a common extension - sinus drain (confluens sinuum). At the pyramids temporal bone transverse sinuses make a downward bend and further under the name sigmoid sinuses infuse into the internal jugular
veins. Thus, blood from both sagittal, direct and occipital sinuses merges into the sinus drain, and from there through the transverse and sigmoid sinuses enters the internal jugular veins.
At the base of the skull is a dense network of sinuses that receive blood from the veins of the base of the brain, as well as from the veins of the inner ear, eyes, and face. On both sides of the Turkish saddle are located cavernous sinuses, which, through sphenoid-parietal sinuses, running along the lesser wing of the sphenoid, the so-called main, bones anastomose with the superior sagittal sinus. Blood from the cavernous sinuses along the upper and lower petrosal sinuses flows into the sigmoid sinuses and then into the internal jugular vein. The cavernous, as well as the lower stony sinuses of both sides, are anastomosed behind the Turkish saddle with the help of intercavernous sinus And venous basilar plexus.
The connection of the sinuses of the base of the skull with the ophthalmic veins, veins of the face (angular veins, pterygoid venous plexus), and the inner ear can cause the spread of infection (for example, with otitis media, boils upper lip, eyelid) on the sinuses of the dura mater and cause sinusitis and sinus thrombosis. Along with this, when the cavernous or stony sinuses are blocked, the venous outflow through the eye veins is disturbed and swelling of the face, eyelids, and periocular tissue occurs. Changes in the fundus that occur with intracranial hypertension are due to a violation of the venous outflow from the cranial cavity and, consequently, the difficulty in the flow of blood from the ophthalmic vein into the cavernous sinus.
8.3. Blood supply to the spinal cord
3 long longitudinal arteries participate in the blood supply of the spinal cord: the anterior and two posterior spinal arteries, which give off thin branches to the substance of the brain; between the arteries there is a network of anastomoses, braiding the spinal cord from all sides (Fig. 8.8).
Anterior spinal artery is formed by the confluence of two branches extending from the intracranial part of the right and left vertebral arteries, and is adjacent to the anterior longitudinal fissure of the spinal cord.
Thus, on the basis of the medulla oblongata is formed rhombus "Zakharchenko's arterial circle", its upper angle is represented by the beginning of the basilar artery, and the lower one by the anterior spinal artery.
Rice. 8.8.Scheme of the blood supply to the spinal cord:
A- arteries of the spinal cord: 1 - posterior spinal artery; 2 - anterior spinal artery; 3 - radicular artery; 4 - watershed; 5 - vertebral artery; 6 - ascending cervical artery; 7 - watershed; 8 - aortic arch; 9 - thoracic intercostal artery; 10 - aorta; 11 - watershed; 12 - Adamkevich's artery; 13 - lumbar artery;
b- veins of the spinal cord: 14 - vertebral vein; 15 - deep cervical vein; 16 - spinal vein; 17 - radicular vein; 18 - lower jugular vein; 19 - subclavian vein; 20 - right brachiocephalic vein; 21 - left brachiocephalic vein; 22 - additional semi-unpaired vein; 23 - unpaired vein; 24 - semi-unpaired vein;V- transverse section of the spine and section of the spinal cord; blood supply: 25 - branch of the spinal nerve; 26 - front spine; 27 - epidural space; 28 - vascular crown; 29 - anterior spinal artery and vein; 30 - posterior spinal arteries; 31 - posterior spinal vein; 32 - anterior radicular vein; 33 - posterior external vertebral venous plexus; 34 - pia mater; 35 - spinal nerve; 36 - spinal ganglion
Two posterior cerebral arteries depart from the intracranial part of both vertebral arteries (sometimes from the inferior cerebellar arteries), and are also a continuation up and down the posterior radicular arteries. They pass along rear surface spinal cord, adjacent to the line of entry of the posterior roots.
The main sources of blood supply to the spinal cord serve as arteries located outside the cavity of the skull and spine. Branches from the extracranial part approach the spinal cord vertebral arteries, deep cervical artery(from the costocervical trunk), other proximal branches of the subclavian artery as well as from posterior intercostal, lumbar, and lateral sacral arteries. Posterior intercostal, lumbar and lateral sacral arteries give away spinal branches, penetrating the spinal canal through the intervertebral foramen. Having given branches to the spine and the spinal node, the spinal arteries are divided into terminal branches that go along with the anterior and posterior roots, - anterior and posterior radicular arteries. Some of the radicular arteries are depleted within the root, others enter the perimedullary vascular network (a complex of small arteries and veins in the pia mater of the spinal cord) or supply blood to the dura mater. Those radicular arteries that reach the spinal cord and merge with the anterior and posterior spinal arteries are called radicular-spinal (radiculomedullary) arteries. It is they who play the main role in the blood supply to the spinal cord. There are 4-8 anterior and 15-20 posterior radicular-spinal arteries. The largest of the anterior radicular-spinal arteries is great anterior radicular-spinal artery(the so-called artery of the lumbar enlargement, or artery of Adamkevich), which supplies the lower half of the thoracic and the entire lumbosacral region.
On the surface of the spinal cord there are unpaired anterior and posterior spinal veins and two paired longitudinal anterolateral and posterolateral veins connected by anastomoses.
The radicular veins carry blood from the venous network of the spinal cord to the anterior and posterior vertebral venous plexuses, which are located in the epidural tissue between two layers of the dura mater. From the venous plexuses, blood flows into the neck into the vertebral, intercostal and lumbar veins. Varicose expansion of the internal vertebral venous plexuses can lead to compression of the spinal cord in the spinal canal.
Defeat syndromes
At half spinal cord injury develops brownsequard syndrome, which, as a rule, is associated with ischemia in the basin of the anterior spinal artery (since the striated arteries extending from the anterior spinal artery supply only one half of the spinal cord). At the same time, deep sensitivity remains on the trunk, since the posterior cord is supplied with blood from the posterior spinal artery.
Transverse spinal cord injury occurs with a simultaneous violation of blood circulation in the basin of the anterior and posterior spinal arteries and is characterized by the development of lower para or tetraplegia (depending on the level of the lesion), loss of all types of sensitivity, and impaired pelvic functions.
An isolated lesion of the basin of the anterior and posterior spinal arteries is possible.
With damage to the anterior spinal artery (syndrome of occlusion of the anterior spinal artery, or Preobrazhensky's syndrome) observed:
The development of paresis or paralysis (at the level of the lesion - flaccid paralysis, below this level - spastic);
Violation of pain and temperature sensitivity according to the conduction type;
Disorder of pelvic functions;
Proprioceptive and tactile sensitivity is preserved. In violation of blood circulation in the basin of the anterior cerebral
arteries above the cervical thickening noted spastic tetraplegia; below the cervical thickening (at the level of the thoracic segments) - spastic paraplegia.
Anterior horn syndrome (anterior polio) occurs with thrombosis of the anterior spinal artery. Electoral defeat motor neurons due to the fact that the gray matter of the spinal cord is more sensitive to ischemia than the white. This syndrome often occurs with lesions at the level of the lumbar enlargement. The clinical picture resembles poliomyelitis (development of flaccid paresis lower extremities). Unlike poliomyelitis, there is no fever, in addition, the syndrome appears at a later age. Often there are warning signs.
Centromedullary infarction syndrome (ischemic lesion of the spinal cord in the central part of its diameter around
central canal) is characterized by flaccid paralysis of the muscles of the trunk and limbs and segmental sensory disorders (syringomyelic syndrome).
In case of circulatory disorders in the pool posterior spinal artery are noted:
Violation of deep sensitivity by conduction type;
Spastic (rarely flaccid) paralysis;
Pelvic disorders.
Syndrome of blockage of the great anterior spinal artery (symptoms of damage to the lower thoracic and lumbar segments) includes:
Flaccid or inferior paraplegia or paraparesis;
Disorders of surface sensitivity according to the conductive type, starting from the level from Th 2-3 to Th 12;
Development of trophic disorders;
Disorders of the function of the pelvic organs.
Syndrome of obstruction of the lower accessory anterior radicular-spinal artery (Desproges-Hutteron artery). This artery is present in 20% of people and is involved in the blood supply to the cauda equina and caudal spinal cord. With its occlusion may develop:
Flaccid paralysis of the lower extremities, mainly in the distal sections;
Decreased sensitivity in the anogenital zone and on the lower extremities;
Pelvic disorders of the peripheral type.
Stanilovsky-Tanon Syndrome (damage to the anterior part of the lumbosacral thickening) is characterized by:
Flaccid lower paraplegia with areflexia;
Violation of pain and temperature sensitivity in the area of the lumbar and sacral segments;
Trophic disorders in the zone of innervation of the lumbar and sacral segments;
A dysfunction of the pelvic organs according to the peripheral type (incontinence).
The cerebellum, the center of higher coordination, and its first forms, formed in simple multicellular organisms that performed voluntary movements. Fish and lampreys do not have a cerebellum as such: instead, these animals have shreds and a worm - elementary structures that support simple coordination of the body.
In mammals, the cerebellum has a distinctive structure, a lateral thickening that interacts with the cerebral cortex. In Homo Sapiens and its predecessors, the cerebellum has developed frontal lobes, which allows them to perform precise small manipulations, such as using a sewing needle, operating on appendicitis, and playing the violin.
The human cerebellum is located in hindbrain along with the Varoliyev bridge. It is localized under the occipital lobes of the brain. Diagram of the structure of the cerebellum: the left and right hemispheres, united by a worm - a structure that connects parts of the small brain and allows information to be exchanged between them.
The small brain consists of white (the body of the cerebellum) and gray matter. The gray matter is the cortex. In the thickness of the white matter, foci of gray matter are localized, forming nuclei - a dense accumulation of nervous tissue intended for certain functions.
The tent of the cerebellum is the part of the dura mater that supports the occipital lobes and separates them from the cerebellum.
Nuclear topography of the cerebellum:
- Dentate nucleus. It is located in the lower parts of the white matter.
- The core of the tent. Localized on the lateral side of the cerebellum.
- Corky nucleus. It is located on the side of the dentate nucleus, it goes parallel to it.
- spherical nucleus. Outwardly, they resemble small balls located next to the cork-like nucleus.
Paired arteries of the cerebellum:
- Superior cerebellar.
- Infero-anterior cerebellar.
- Inferoposterior.
In 4-6%, an unpaired 4th artery occurs.
Functions of the cerebellum
The main function of the cerebellum is the adaptation of any movements. The “small brain” tasks are determined by three levels of the organ:
- Vestibulocerebellum. The most ancient department from an evolutionary point of view. This area is connected to the vestibular apparatus. It is responsible for the balance of the body, the joint coordination of the eyes, head and neck. Vestibulocerebellum provides a synchronous turn of the head and eyes with a sudden stimulus.
- Spinocerebellum. Thanks to connections with the spinal cord, from which the small brain receives information, the cerebellum controls the position of the body in space. Spinocerebellum controls muscle tone.
- Neocerebellum. Connects with the cerebral cortex. The newest department is involved in the regulation and planning of movements of the arms and legs.
Other functions of the cerebellum:
- synchronization of the speed of movement of the left and right eyes;
- synchronous rotation of the body, limbs and head;
- calculation of the speed of movements;
- preparation and compilation of a motor program to perform higher manipulation skills;
- accuracy of movements;
Little-studied features:
- regulation of the muscles of the speech apparatus;
- mood regulation;
- speed of thought.
Symptoms
Cerebellar disorders:
Ataxia is unnatural and wobbly gait, in which the patient spreads his legs wide, balances with his hands. This is done to prevent falls. The patient's movements are uncertain. With ataxia, walking on the heels or toes is disturbed.
Dysarthria. Loss of fluidity of movement. With bilateral damage to the cerebellum, speech is disturbed: it becomes lethargic, inarticulate, slow. Patients repeat several times.
Adiadochokinesis. The nature of the affected functions depends on the location of damage to the structures of the small brain. With organic damage to the cerebral hemispheres, the amplitude, speed, strength and timeliness of movements (beginning and ending) are upset. The smoothness of movements is disturbed, the synergy between the flexor and extensor muscles is lost. Movements during adiadochokinesis are uneven, spasmodic. Decreased muscle tone. Initiation in muscle contraction is delayed. Often accompanied by ataxia.
Dysmetria. The pathology of the cerebellum is manifested in the fact that the end of an already begun movement is disturbed. For example, when walking, a person moves evenly with both legs. The patient's leg can "get stuck" in the air.
Asthenia and dystonia. The muscles become rigid, and the tone in them is unevenly distributed. Dystonia is a combination of weakness of some muscles with hypertonicity of others. It is natural that in order to complete full-fledged movements, the patient has to make great efforts, which increases the energy consumption of the body. As a result, asthenia develops - pathological weakness in the muscles.
Intention tremor. Violation of the cerebellum of this type leads to the development of tremor. Tremor can be different, but cerebellar tremor is characterized by the fact that the arms and legs tremble at the stage of the end of movements. With the help of this sign, a differential diagnosis is made between cerebellar tremor and trembling of the extremities in case of damage to the nuclei of the brain.
Combination of ataxia and dysmetria. It occurs when the messages between the cerebellum and the motor centers of the cerebral cortex are damaged. main feature- loss of the ability to complete the initiated movement. Towards the end of the final phase, trembling, uncertainty and unnecessary movements appear that would help the patient correct his inaccuracies. Problems with the cerebellum at this level are detected using the knee-calcaneal and finger-nose tests. The patient is offered, with his eyes closed, first to put the heel of one foot into the knee of the other, and then touch the tip of the nose with his finger. Usually, with ataxia and dysmetria, the movements are uncertain, not smooth, and the trajectory is zigzag.
Combination of asynergy, dysdiadochokinesia and dysarthria. A complex combination of disorders is characterized by a violation of complex motor acts and their synchrony. In the later stages, such cerebellar neurology gives rise to speech disorder and dysarthria.
Some people mistakenly think that the back of the head hurts the cerebellum. This is wrong: pain originate not in the substance of the small brain, in the surrounding tissues, which are also involved in the pathological process.
Diseases and pathological conditions
Atrophic changes in the cerebellum
Signs of atrophy:
- headache;
- dizziness;
- vomiting and nausea;
- apathy;
- lethargy and drowsiness;
- hearing impairment; walking disorder;
- deterioration of tendon reflexes;
- ophthalmoplegia - a condition characterized by paralysis of the oculomotor nerves;
- speech disorder: it becomes inarticulate;
- trembling in the limbs;
- chaotic oscillation of the eyeballs.
Dysplasia is characterized by abnormal formation of the substance of the small brain. The tissues of the cerebellum develop with defects originating in fetal development. Symptoms:
- difficulty performing movements;
- tremor;
- muscle weakness;
- speech disorders;
- hearing defects;
- deterioration of vision.
The first signs appear by the first year of life. Symptoms are most pronounced at 10 years of age.
Cerebellar deformity
The cerebellum can be deformed for two reasons: tumor and dislocation syndrome. Pathology is accompanied by a violation of blood circulation in the brain due to compression of the tonsils of the cerebellum. This leads to a violation of consciousness and damage to the vital centers of regulation.
Cerebellar edema
Due to the increase in the small brain, the outflow and inflow of cerebrospinal fluid are disturbed, which causes cerebral edema and stagnation of cerebrospinal fluid.
Signs:
- headache, dizziness;
- nausea and vomiting;
- disturbance of consciousness;
- fever, sweating;
- difficulty holding a posture;
- unsteadiness of walking, patients often fall.
When the arteries are damaged, hearing is impaired.
Cerebellar cavernoma
The cavernoma is benign tumor that does not spread metastases to the cerebellum. There are severe headaches and focal neurological symptoms: impaired coordination and accuracy of movements.
It is a hereditary neurodegenerative disease, accompanied by a gradual death of the cerebellar substance, which leads to progressive ataxia. In addition to the small brain, conduction pathways and the brain stem suffer. Late degeneration appears after 25 years. The disease is transmitted in an autosomal recessive manner.
The first signs are unsteadiness of walking and sudden falls. Speech is gradually upset, muscles weaken and the spine is deformed by the type of scoliosis. 10-15 years after the first symptoms, patients completely lose the ability to walk independently and need help.
Causes
Cerebellar disorders have the following causes:
- . The blood supply to the organ is deteriorating.
- Hemorrhagic and ischemic stroke.
- Elderly age.
- Tumors.
- Injuries to the base of the skull and occipital region.
Diagnosis and treatment
Diagnosis of diseases of the small brain can be done using:
- . The method reveals hemorrhages in the substance, hematomas, tumors, birth defects and degenerative changes.
- Lumbar puncture followed by examination of the cerebrospinal fluid.
- External neurological examination. The doctor, with the help of an objective study, studies the coordination of movements, the stability of walking, the possibility of maintaining a posture.
Cerebellar disorders are treated by addressing the underlying cause. For example, in infectious diseases, antiviral, antibacterial and anti-inflammatory drugs are prescribed. Adjuvant therapy is provided for the main treatment: vitamin complexes group B, angioprotectors, vasodilators and nootropics that improve the microcirculation of the substance of the small brain.
If there is a tumor, surgery will be required on the cerebellum with a crossbow incision at the back of the head. The skull is trepanated, the superficial tissues are dissected, and the surgeon gains access to the cerebellum. In parallel, to reduce intracranial pressure, the ventricles of the brain are pierced.
Relevance. In the structure of cerebrovascular diseases, the frequency of cerebellar infarcts varies from 0.5 to 1.5% of all cerebral infarctions, and mortality in them exceeds 20%. Cases of hemorrhages in the cerebellum account for about 10% of all intracranial hemorrhages, the lethality in them reaches 30% or more. However, strokes in the brainstem and cerebellum are among the least studied issues. vascular pathology brain. The variety of clinical manifestations of cerebellar strokes, their frequent similarity with some manifestations of hemispheric strokes and various lesions peripheral vestibular apparatus significantly complicate their timely diagnosis. In addition, in vascular diseases of the brain in an isolated form, cerebellar syndrome is rare and is usually accompanied by signs of damage to the brain stem, which is naturally explained by the common blood supply of these structures.
You can read about hemorrhages in the cerebellum in the article (lecture) “Hemorrhagic stroke of the posterior cranial fossa” by V.V. Krylov, V.G. Dashyan, A.A. Murashko, S.A. Burov, Research Institute of Emergency Medicine. N.V. Sklifosovsky, Moscow State Medical and Dental University (journal "Neurosurgery" No. 4, 2006) [read].
The blood supply of the cerebellum has been studied in detail. In normal anatomy, the cerebellum receives its blood supply from the vertebrobasilar system, from 3 paired cerebellar arteries: the superior cerebellar artery (SCA), the anterior inferior cerebellar artery (AICA) and the posterior inferior cerebellar artery (PICA). The proximal sections of all cerebellar arteries are involved in the blood supply to the dorsolateral sections of the brain stem. In normal anatomy, all cerebellar arteries anastomose with each other through a well-developed collateral network. The SCA partially supplies blood to the inferior tubercles of the quadrigemina, the ventral sections of the cerebellum, as well as its upper and middle dorsal sections, most dentate nucleus. PNMA supplies blood to the lateral parts of the lower third of the pons and upper third medulla oblongata, a piece of the cerebellum and adjacent parts of the hemisphere; An important branch of the AICA is the labyrinthine artery, which supplies blood to inner ear. ZNMA supplies blood to the lateral sections middle third medulla oblongata, caudal and basal cerebellum.
In the structure of cerebellar ischemic stroke, the damage to its vascular pools is distributed as follows: VMA - 30 - 40%, CICA - 3 - 6%, CICA - 40 - 50%, stroke in pools of 2 or more cerebellar arteries - up to 16%. With an introduction to clinical practice New types of cerebellar infarcts have been established by neuroimaging techniques: watershed infarcts or borderline infarcts, very small (lacunar) infarctions. With OA thrombosis, infarcts are more often localized in the territory of the superior cerebellar artery (SCA) and are usually combined with brainstem infarcts.
In chronic circulatory disorders in the pools of the cerebellar arteries in patients with or without transient ischemic attacks, the development of lacunar, deeply located infarctions is observed, caused by damage to penetrating arteries with a diameter of 40–900 μm. Their frequency is 25 - 28% of all cases of cerebellar infarction. Small deep cerebellar infarctions are found mainly in the border zones of vascularization of the three cerebellar arteries. characteristic feature lacunar infarcts is a favorable outcome with partial or complete clinical recovery. The dimensions of lacunae on horizontal sections of the brain during CT and MRI scans usually do not exceed 12–20 mm, and the average volume is 1.7–1.8 ml.
The modern topography of cerebellar infarcts is assessed using a map that allows you to establish anatomical correspondence to the main arterial pools. Currently, the topographic classification of cerebellar infarcts proposed by R. Amarenco (1991) and supplemented by L. Tatu et al. (1996):
Cerebellar infarctions are usually found in middle-aged and elderly patients, and in men about 2.5 - 3 times more often than in women. Cerebellar ischemic strokes occur predominantly due to thromboembolism from the heart, vertebral or basilar artery or by a hemodynamic mechanism. Embolism in the cerebellar artery has been described in recent myocardial infarction and atrial fibrillation. Among other factors, one should also note various kinds of manipulations on the neck (especially rotations), which can be complicated by traumatization of the vertebral arteries and the occurrence of an acute disorder. cerebral circulation. The defeat of small arterial branches (causing lacunar infarcts) is associated with the development of microatomas, lipogyalinosis and fibrinoid necrosis in them. The cause of the development of lacunar infarcts are also microemboli. Arterial hypertension is generally recognized as risk factors for the development of lacunar infarcts, diabetes, vasculitis. In patients under 60 years of age, the most common cause cerebellar infarction is an intracranial dissection of the VA, including the orifice of the posterior inferior cerebellar artery (PICA). More rare causes cerebellar infarction - hematological diseases, fibromuscular dysplasia. In some cases, the cause cannot be determined.
Diagnosis of isolated cerebellar strokes is very difficult if CT or MRI is not performed in the first two days of the disease. Small cerebellar infarctions are often not clinically detected due to the rapid reversibility of clinical manifestations. At the same time, it is known that in 25% of cases, extensive cerebellar infarctions are preceded by small strokes or transient disorders cerebral circulation mainly in the vertebrobasilar, less often in the carotid systems (about 40% of patients with cerebellar infarction simultaneously have heart attacks in other vascular regions of the brain). Extensive infarctions and hematomas of the cerebellum with their timely diagnosis may be amenable to surgical treatment that prevents fatal dislocations. In the absence of progressive secondary hydrocephalus, 80-90% of patients with cerebellar stroke survive with conservative treatment tactics. MR tomography is the leading method in the diagnosis of stem and cerebellar strokes.
Consider the clinic isolated cerebellar infarction (in the basins of the cerebellar arteries). In the case of an isolated lesion of the cerebellum in the PICA basin, the clinical picture is dominated by vestibular disorders, the most common symptoms are: dizziness (80%), headache in the cervical-occipital region (64%), nausea (60%), gait disturbance (70% ), ataxia (50%), nystagmus, rarely dysarthria. According to the observations of some authors, in the case of a heart attack in the basin of the medial branch of the PICA, the clinical picture of the disease can only be dizziness, (!) Such patients are often diagnosed with labyrinthitis. In the case of an isolated lesion of the cerebellum in the SMA basin, the clinical picture is dominated by coordinating disorders, since the dentate nuclei are affected. Symptoms in this case are usually as follows: ataxia (73%), gait disturbance (70%), dysarthria (60%), nausea (40%), dizziness (37%), nystagmus (7%). In the clinical picture of myocardial infarction in the AICA basin common symptom is hearing loss on the side of the infarction, other typical cerebellar symptoms are variable in severity, it is also ataxia, gait disturbance, dizziness, nausea, nystagmus.
read also the article "Mnemonic Rule of Cerebellar Dysfunction: Express Help for a Practitioner" Murashko N.K. P.L. Shupika, Kyiv (International neurological journal, No. 6, 2013) [read]
Among the isolated cerebellar infarctions, an extensive cerebellar infarction should be singled out separately due to the clinical features of the course of this form of stroke. Extensive cerebellar infarction usually occurs when the entire SMA or PICA area is affected, most often in the PICA area with acute vertebral artery (VA) occlusion. Extensive cerebellar infarction in most cases is clinically characterized by the acute development of cerebral, vestibular, coordinating and stem disorders (alternating syndromes, disturbed wakefulness, respiratory disorders etc.) in various combinations [since all three cerebellar arteries widely anastomose with each other, extensive infarcts accompanied exclusively by cerebellar syndrome are very rare and, as a rule, they occur against the background of the development of stem disorders]. With this form of cerebellar ischemic stroke, on the 2nd - 3rd day of the disease, a pronounced edema of the infarct zone develops, which has a mass effect. Such a complicated course of cerebellar infarction is malignant and occurs in 5–15% of all cases of cerebellar stroke (the main factor contributing to the development of a malignant course of cerebellar infarction is the volume of the lesion - at least 1/3 of its hemisphere or [according to M. Koh et al. , 2000] ~24 cm3). In this case, compression of the CSF-conducting structures of the posterior cranial fossa (PCF) occurs, which leads to the development of acute occlusive hydrocephalus (OH) and further fatal damage to the brain stem. Even in the case of a timely diagnosed and urgently drained OOH, an increase in the mass effect in the PCF can lead to ascending transtentorial herniation and/or herniation of the cerebellar tonsils into the foramen magnum, which leads to a secondary fatal injury to the brainstem. Mortality in this malignant form of stroke conservative treatment is 80%. Such a malignant course of cerebellar infarction urgently requires the involvement of a neurosurgeon and the solution of the issue of surgical treatment: external ventricular drainage and / or decompressive craniotomy of the PCF. Timely performed surgical intervention can reduce mortality by up to 30%. In a number of cases, clinical deterioration is associated with the expansion of the ischemic zone and the involvement of the stem sections in it, while the positive effect of surgical intervention becomes unlikely.
You can read more about extensive cerebellar infarction in the article “Extensive cerebellar infarction causing dislocation syndrome and indications for emergency surgery” by S.A. Asratyan, A.S. Nikitin, City clinical Hospital No. 12, Moscow (Journal of Neurology and Psychiatry, 12, 2012; Issue 2) [read].
The ratio of vestibular and cerebellar disorders in cerebellar (cerebellar) stroke is one of the most difficult diagnostic problems. The study of clinical and MR-imaging manifestations in patients with acute and subacute cerebellar and vestibular disorders against the background of arterial hypertension and cerebral atherosclerosis showed the presence of structural focal pathological changes vascular nature in all patients without exception. These data emphasize the need for an MRI scan within 1–3 days from the onset of an acute episode of vestibulo-atactic syndrome in patients with vascular risk factors.
Systemic vertigo (vertigo) is the leading symptom in single and multiple cerebellar infarctions localized in the area of territories of any of the three paired cerebellar arteries or in areas of adjacent blood supply. Detectable dizziness and nystagmus inherent in a central lesion, in cases of localization of infarcts in the basin of the anterior inferior cerebellar artery, which, as is known, has cerebellar, pontine and labyrinth branches, can mimic the peripheral nature of the lesion of the vestibular analyzer, mask cerebellar disorders, while complicating the diagnosis of an acute vascular process . The occurrence of pseudolabyrinth syndrome in cerebellar infarcts is associated with a violation of the inhibitory effects of the cerebellum on the vestibular nuclei. IN acute phase ischemic stroke or hemorrhage of cerebellar localization, the greatest diagnostic difficulties are possible, since neurological symptoms characteristic of direct damage to the cerebellum may be absent at this stage. In the future, the predominance of postural disturbances over dynamic coordinating ones is often noted, which also masks the cerebellar localization of the process in the acute stage of the disease. Focal cerebellar symptoms in some cases may be mild or absent. Therefore, the leading value in the timely differential diagnosis cerebellar stroke has magnetic resonance imaging of the brain, carried out on the first day from the onset of acute vestibulo-atactic syndrome in order to timely start specific therapy for ischemic and hemorrhagic strokes, which is the real basis for a favorable outcome of one of the most severe types of cerebrovascular pathology.
Main instrumental method diagnosis of cerebellar strokes is neuroimaging. However, in acute period diseases (during the first 8 hours) are not yet determined by CT of the ischemic zone. MRI is a more sensitive method of visualizing cerebellar infarction, as there are no artefacts from the bone structures of the PCF in the images. In the most acute period of the disease, the infarction zone can be determined using diffusion-weighted MRI and perfusion research methods: perfusion CT or MRI, single-photon emission CT (SPECT).
read also the post: Difficulties in diagnosing stroke (infarction) of the cerebellum(to the website)
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Posts from This Journal by “heart attack” Tag
Neuroimaging of cerebral infarctionWhen a patient with a suspected stroke enters a medical facility, the goal of the medical staff is to assess the severity of his condition.…
The superior cerebellar artery is one of the branches of the basilar artery, leaving it at an angle of 90 °, dividing into two or three branches.
Structure
The superior cerebellar artery can be a single trunk or divided in two ways:
- two branches: anterior superior and posterior inferior cerebellar artery, when each of the branches goes in a separate trunk. In this case, the lower part is the main branch, and the upper one is divided into two parts;
- three branches, when each of the trunks is divided into branches.
Depending on the anatomical features buildings share several zones of blood supply to a given element of the circulatory system.
Doctors distinguish following groups branches of the anterior and posterior inferior cerebellar arteries:
- branches for the upper surface of the cerebellum;
- bridge branches that feed the region of the anterior edge of the pons;
- branches that feed the legs of the brain and the quadrigemina.
This vessel is considered the most constant among all the arteries of the cerebellum. It can start from either the left or right side at the top of the main artery.
The diameter of the main trunk of the ZNMA is 1-1.5 mm. The diameter of additional trunks is 0.5-1 mm. Studies show that on the left side, the diameter blood vessel usually a little more than on the right.
Large branches of the artery are usually located perpendicular to the sulci of the cerebellum.
blockage of an artery
The most common problem is blockage of the superior cerebellar artery:
- proximal. In this case, the blockage is found at the site of separation of the cerebellar artery from the main artery;
- medial. It occurs along the cerebellar artery. This type of pathology is the most common;
- distal. In this case, there is a blockage of one of the cerebellar branches.
In all cases, the following clinical picture: incoordination.
The cerebellar arteries are responsible for feeding the cerebellum.
In case of problems with the nutrition of the cerebellum, there is:
- a symptom of "oblique position", when the patient cannot walk in a straight line, gradually deviating;
- violation motor function upper and lower limbs;
- paresis facial muscles, violation of facial expressions;
- problems with the vestibular apparatus;
- hearing loss, tinnitus;
- nausea and vomiting;
- myoclonus (sudden contractions) soft palate, faces, diaphragms.
Most dangerous situation is a stroke of the cerebellum, which appears in the event of a hemorrhage in the brain. Most often, it develops in people over 60 years old, although recently the disease has become “younger”, and sometimes a stroke develops in 30-40-year-old people. The mortality rate is quite high (about 30%), but even if the patient survives, the rehabilitation period is very long, and returning to a full life is not possible in all cases.
Reasons for the appearance
A stroke is caused by a blockage in the cerebellar artery that supplies the cerebellum. Most often, blockage occurs due to the development of atherosclerosis, in which fatty plaques are deposited on the walls of blood vessels, preventing normal blood flow. Sometimes the superior cerebellar artery is stratified, and therefore the disease develops in very young patients.
The following factors contribute to the development of cerebellar stroke:
- diabetes;
- pathological destructive processes in the walls of blood vessels;
- excess body weight;
- high blood pressure;
- endocrine disorders;
- lack of physical activity;
- inflammatory processes on the walls of the cerebellar artery;
- diseases that can cause blood clots, such as endocarditis.
Clinical manifestations
As a result of blockage of the cerebral artery, an extensive or local (isolated) cerebellar stroke can develop.
An isolated stroke occurs when blood flow to the posterior inferior part of the cerebellar artery is interrupted. The first symptom is severe dizziness, then nausea appears, the coherence of speech is disturbed, the patient cannot walk smoothly.
In the case of damage to the anterior inferior cerebellar artery, speech, gait and motor skills are also impaired, but auditory disorders are added to the symptoms. Depending on where the problem is located, hearing impairment develops on the right or left.
If the superior cerebellar artery was affected, then there is a violation of coordination. The patient cannot maintain balance, make precise movements, and clearly pronounce phrases.
The problem of making a diagnosis is that in the case of a small hemorrhage from the cerebellar artery, the symptoms are not very pronounced. dizziness and slight violation motility can be a symptom of many diseases, and therefore in this case it is not uncommon for a doctor to make an incorrect diagnosis. If the focus of hemorrhage is minimal, then the body recovers quickly enough, but often a microstroke is a precursor to an extensive hemorrhage.
A massive stroke is extremely life-threatening for the patient. Most often it can be observed in the superior cerebellar artery.
Symptoms of a massive cerebellar stroke are:
- headache and dizziness that come on unexpectedly;
- impaired motor skills and coordination of movements;
- cardiac and respiratory disorders.
In case of damage to more than 30% of the cerebellum, severe edema can occur, compressing the brain and causing the death of the patient. In this case, urgent intervention by a neurosurgeon is required, but even in this case, every third patient dies.
In the case of an increase in the focus of necrosis, the patient's condition intensifies the clinical picture, and the prognosis is even more unfavorable.
Treatment
In the event of a cerebellar stroke, it is necessary to take measures to save the patient's life and prevent the situation from aggravating:
- artificial ventilation of the lungs if necessary;
- lowering blood pressure;
- reduction of cerebral edema;
- elimination of convulsive syndrome (in severe cases, anesthesia can be used);
- calming the patient.
Nutrition should be carried out through a probe.
Specific therapy is aimed at restoring normal blood flow through the superior cerebellar artery. For this, anticoagulant and antiplatelet therapy is prescribed or surgical intervention is performed.
Restoration of cerebellar functions should be started as quickly as possible, and then there are chances to minimize negative consequences for the patient. At the same time, the recovery period itself can take years and should be carried out under the constant supervision of specialists from rehabilitation centers.
