The variant of the development of the circle of Willis is the absence of blood flow through the posterior communicating arteries. What is the circle of Willis. Signs of violations and methodology for diagnosing VC anomalies

The variant of the development of the circle of Willis is the absence of blood flow through the posterior communicating arteries. What is the circle of Willis. Signs of violations and methodology for diagnosing VC anomalies

27.08.2020 Products

Most frequent reasons such diseases are: atherosclerosis, tuberculosis, fibromuscular dysplasia and others.

Among them, the most common violations occur due to atherosclerosis. With impaired metabolism, cholesterol is deposited in the vessels in the form of atheromatous plaques, which causes sclerosis of the arterial pathways (an increase in connective tissue). As a result, a narrowing of the artery of the brain occurs. Over time, atheromatous plaques are destroyed, which can lead to vessel thrombosis.

Vertebrobasilar system

The vertebrobasilar system is formed from the vertebral arterial vessels and the main (basilar) artery, which is formed from the fusion of the vertebral vessels. The vertebral blood pathways originate, like the sleepy ones, in the chest cavity and through the bony canal of the cervical vertebrae reach the brain. Their connection occurs in the region of the posterior cranial fossa, where the main artery is formed.

The basilar vascular pathway is responsible for supplying blood to the posterior regions of the brain. The most common diseases are thrombosis and aneurysm.

The occurrence of thrombosis is facilitated by vascular damage, which can be caused by a variety of factors, from trauma to atherosclerosis. Complications of thrombosis are embolism, as a result of which thromboembolism develops. The disease is accompanied by neurological symptoms that indicate the presence of lesions of the bridge. Also, there are acute disorders of cerebral functions, stagnation of blood in the capillaries due to impaired functions of cerebral circulation. As a result, a stroke is possible.

With an aneurysm of the artery of the head (protrusion of the vessel wall), hemorrhage into the brain is possible, as a result of which damage to its tissues or even death is possible. Therefore, it is extremely important, at the slightest suspicion, to carry out a complete diagnosis of all vessels of the head.

Deposits of atherosclerotic plaques in the basilar artery can lead to its occlusion and, as a result, to ischemic stroke.

The circle of Willis consists of the main arteries of the head and is responsible for the blood supply to the brain tissues. Consists of two anterior, two posterior and two middle cerebral arteries, as well as two posterior connecting arterial pathways and an anterior connecting vessel.

Depending on the visualization of all the listed vessels, it can be closed (when all vessels are visualized) or not closed (in the absence of visual observation of at least one vessel, or its segment).

The main purpose of the circle of Willis is compensatory activity. In case of insufficient blood flow in one of the arteries of the brain, the Willis circle compensates for this deficiency from the remaining blood pathways, thereby ensuring stable and uninterrupted functioning of the brain.

The development of the circle of Willis is not a very frequent phenomenon in the norm, and is about 37%. Quite often, it is characterized by underdevelopment, which is not a disease, but can lead to a more negative course of diseases, since its compensatory function is not fully realized.

Narrowing of the cerebral artery with hypoplasia or the development of aneurysms quite often occurs just in the circle of Willis.

Diseases of the arteries of the brain

The brain requires a significant amount of resources for its work, which are supplied with blood. To provide these resources, four rather large vessels are intended, which are located in pairs. In addition, there is the circle of Willis, in which most of the blood pathways are reduced. Its purpose is to compensate for the supply of blood vessels due to their insufficiency in diseases of various origins, injuries or pathologies. With an insufficient supply of blood from one of the vessels, this deficiency is redistributed to the rest of the vessels.

In this way, the compensatory abilities of the circle of Willis make it possible to compensate for the deficiency that has appeared even with two non-working vessels, and at the same time the person will not even notice anything. But, nevertheless, even such a powerful mechanism does not always cope with the loads that a person creates for his body.

The most common signs of diseases associated with the arteries of the head are headache, increased fatigue, and dizziness.

If the diagnosis is not made in time, then over time the disease can progress, and as a result - damage to the brain tissue, which occurs with discirculatory encephalopathy (circulatory failure in the brain of a chronic nature).

The main reasons for such a disease are the presence of atherosclerosis in the patient and / or arterial hypertension... Since both diseases are quite common, the possibility of developing discirculatory encephalopathy is quite high.

In addition, osteochondrosis can contribute to the development of the disease. This is due to the fact that with osteochondrosis, the intervertebral discs are deformed, which, during deformation, can clamp the vertebral artery that runs between the vertebrae. As a result, the blood supply by the arteries of the brain is disrupted, and if the Willis circle does not cope with its function, the brain does not have enough resources for normal functioning. There is a gradual death of neurons, which in turn leads to the appearance of neurological symptoms.

Dyscirculatory encephalopathy does not decrease over time, but, on the contrary, progresses. This creates the risk of many diseases, among which the most dangerous are stroke and epilepsy. Indeed, among those who have suffered a stroke, only half of them continue to live on, since some die immediately, and some die throughout the year.

That's why early diagnosis and treatment is extremely important in the disease of the arterial pathways of the brain.

What does brain leukoencephalopathy mean?

Leukoencephalopathy of the brain is characterized by the development of disorders on the part of the white matter of the brain. This disorder is initially described as vascular dementia. Most often, this ailment occurs in people in old age.

What is Leukoencephalopathy in the Brain Region? This is a progressive disease, usually chronic. Over time, pathological changes are accompanied by the appearance of dementia.

The complete destruction of nerve cells occurs as a result of disturbances from the processes of oxygen supply and blood supply. These factors contribute to the development of microangiopathy, which is fraught with a change in the density of the white matter. This condition indicates that there are disturbances in the blood circulation processes in the body.

Types of leukoencephalopathy

The disease can occur in several varieties. In accordance with the form of the pathological process, treatment is prescribed.

Small focal (vascular genesis)

At vascular leukoencephalopathy the brain is slowly affected by the hemispheres of the brain, which is accompanied by the appearance of clinical symptoms. This form of the disease occurs against the background of hypertension, accompanied by jumps blood pressure.

The risk group includes men over the age of 55. Basically, the disease occurs in those people whose relatives have also experienced similar disorders. Pathological changes in the white matter lead over time to senile dementia.

Progressive vascular leukoencephalopathy occurs against the background of the following reasons:

What is small focal leukoencephalopathy of vascular origin? These are the consequences of being overweight, alcohol and smoking abuse, eating disorders and lack of physical activity. The presence of risk factors requires prevention of the development of pathological disorders even before the symptoms of the disease appear.

Multifocal (progressive)

This form of brain disorders is a viral lesion of the nervous system. This process is accompanied by a pronounced liquefaction of the white matter. The main reasons for the occurrence of deviations are a decrease in immunity. Multifocal leukoencephalopathy is aggressive and can be fatal.

What is periventricular leukoencephalopathy? This is the development of cognitive impairment that can range from severe dementia to mild dysfunctions. With a focal form of the disease, neurological symptoms are observed. This is fraught with the development of speech and vision disorders.

Most often, this form of the disease occurs in patients with acquired or congenital immunodeficiency. The risk group includes people who have AIDS or HIV.

Periventricular (focal)

It is characterized by a lesion of the subcortical structure in the region of the brain. Occurs due to chronic ischemia and hypoxia. It develops in the cerebellum and brain stem.

What is periventricular leukoencephalopathy? This is a lesion of the motor nuclei in the area medulla oblongata... It develops rapidly and is accompanied by severe impairment of motor activity.

Symptoms of leukoencephalopathy

Most often, the development of leukoencephalopathy is accompanied by a gradual increase clinical picture... Among the primary manifestations are absent-mindedness, awkwardness and apathy. The person becomes clumsy and tearful. As a rule, there is a decrease in mental performance. Sleep is gradually disturbed, irritability and muscle hypertonia occur.

The development of the clinical picture:

Focal neurological symptoms progress quickly enough. The patient may have pseudobulbar and parkinsonian syndrome. On examination, in almost all cases, there are malfunctions on the part of intellectual and mnestic functions.

The patient suffers from postural instability. Mental disorders are combined with constant anxiety, nausea, headaches and numbness of the limbs.

In almost all cases, patients do not perceive that they need help, therefore, as a rule, relatives bring them to the doctor.

Establishing diagnosis

With the development of multifocal progressive leukoencephalopathy, vascular and periventicular form of the disease, it is required to conduct comprehensive diagnostics, which includes the following procedures:

Consultation and visual examination at an appointment with a neurologist;
Sampling of tests: blood, determination of the level of drugs and alcohol;
Doppler ultrasonography, MRI, CT, EEG;
PCR, brain biopsy and lumbar puncture.

Supportive drug therapy

A person cannot completely recover from leukoencephalopathy. Despite this, it is imperative to go to a doctor who will prescribe supportive drug therapy. These activities are necessary to stop the progression of the disease and activate the functions of the brain.

High efficiency is given by antiviral drugs which have fat-soluble functions. Unfortunately, at present, most drugs have only a water-soluble effect, which significantly complicates the treatment process. That is why, in case of leukoencephalopathy, treatment should be prescribed by an experienced specialist, which increases the patient's chances of stopping the progression of pathological changes in the brain area.

The tactics of treating the disease have been developed over the years. Experts have tried a number of drugs, which have different efficacy in the fight against leukoencephalopathy:

Preparations for improving cerebral circulation - "Cavinton", "Pentoxifylline";
Means with angioprotective properties - "Plavix", "Cinnarizin", "Curantil";
Nootropic drugs - Nootropil, Piracetam;
Antiviral therapy - Kipferon, Acyclovir;
Anti-inflammatory drugs - "Fragmin", "Heparin";
Adaptogens - "Aloe extract", "Vitreous humor";
Vitamins A, E and B;
Medicines with antidepressant properties - "Prozac".

Reflex and physiotherapy are prescribed as measures complementing complex therapy. Without fail, the patient attends sessions of breathing exercises and massage in the area of the collar zone. High efficiency possesses acupuncture and manual therapy.

For patients childhood drug therapy is being replaced by physiotherapy and homeopathic drugs.

Disease prognosis

Unfortunately, currently no therapy has been developed that would help to completely cure leukoencephalopathy. If measures are not taken at all, then the patient's life expectancy is no more than 6 months from the moment the symptoms of damage to the central nervous system appeared.

Antiviral treatment helps to increase the patient's life expectancy up to 12 months. In some cases, the survival time is 1.5 years from the moment the first changes in the brain structures appeared.

Given the fact that the development of any form of leukoencephalopathy occurs against the background of immunodeficiency, in order to exclude the development of the disease, it is necessary to observe all possible measures for its prevention. Each person should take care of the safety of the body's defenses and strengthen them. Measures must be taken without fail to prevent HIV and AIDS.

Main measures:

Sex partner selectivity and the use of drugs that make intercourse safe.
Refusal to use drugs.
Timely treatment of diseases associated with surges in blood pressure and vascular occlusion.

Possible pathologies of the circle of Willis and their treatment

The human brain (GM) is a delicate structure that performs an enormous amount of work. A prerequisite for the functioning of any organ is normal blood circulation. The first person to describe the arterial circulation in the brain was Willis Thomas, an anatomist and neurologist from Great Britain. Since then, the vascular ring of the brain has been named after him.

The structure and function of the arterial circle of the brain

Decreased blood circulation in the brain is life-threatening. The human anatomy is such that the arterial ring (circle of Willis) located in the subarachnoid space at the base of the brain performs the function of compensating for insufficient blood flow.

The cerebral vessels are interconnected (anastomosed) on the basis of the GM. The following vessels form the pool of the circle of Willis:

Anterior cerebral artery: the initial segment (a. Cerebri anterior).
Anterior communicating artery (a.communicans anterior).
Internal carotid artery: supracliniform segment (a. Carotis interna).
The back connecting artery (a.communicans posterior).
Posterior cerebral artery: the initial segment (a. Cerebri posterior).

In his work, Willis Thomas describes an anastomosis in the form of a heptagon - heptagon Willis. But after conducting research, M.A.Tikhomirov revealed that the shape of the ring is nine-cornered. The connection between the GM vessels is centralized in the circle of Willis.

Impaired blood flow in the cervical vessels can lead to insufficient blood circulation to the brain. To prevent a situation of reduced blood flow, a "fallback" option is provided - a compensatory arterial circle. This is its function. The carotid arteries, connecting with each other, anastomose with the vertebrates. It is thanks to this connection, in case of obstruction of the vessels of the brain, blood circulation is not disturbed and all tissues receive a sufficient amount of substances.

Pathologies and their symptoms

The correct development of the circle of Willis is evidenced by its symmetry on both sides. But this development is observed only in 50% of the population. Failure of vascular development is often observed - hypoplasia. There is a mismatch in the size of the arteries from different sides, the lack of symmetry in their discharge. If all vessels are interconnected and symmetrically depart on both sides, then they say that the arterial circle is closed. This makes it possible to completely replenish the blood flow in the event of pathology of other vessels.

The most gross anomaly in the structure of the ring is openness. It occurs when there is no connection of the main artery - with the vertebrates. There are two variants of pathology: the circle is completely open if the connecting arteries are absent and not completely open, if there is a narrowing or hypoplasia of the connecting arteries.

A frequent localization of cerebral aneurysms is the circle of Willis. The danger lies in the fact that for a long time the aneurysm does not cause any symptoms. The patient's condition worsens when it breaks. If help is not provided in a timely manner, then the person falls into a coma.

The results of the study show that there is a connection between the asymmetric structure of the circle of Willis and the occurrence of migraine. Pathology is revealed by chance during magnetic resonance imaging. Under the condition of normal blood circulation in the brain, when the arterial circle does not fulfill its compensatory function, the symptoms do not appear.

Diagnostics and treatment

To study the state of blood vessels in medicine, the method of angiography is used. The most accessible diagnostic method is considered to be transcranial dopplerography, which allows assessing the blood flow in the cerebral arteries. This method has a large number of advantages, because it allows you to assess the state of the vascular lumen, the speed and direction of blood flow. To make a diagnosis, a comprehensive examination is used that evaluates all the criteria for the structure of the arteries and the characteristics of the blood supply in them.

The presence of an anomaly in the development of the arterial circle does not pose a danger to the quality of human life, provided that there are no circulatory disorders in the vessels of the brain; therefore, no treatment is prescribed. If the pathology manifests itself in the form of migraine, then the attending physician may prescribe you to take painkillers.

If an aneurysm is detected in the vessels of the circle of Willis, surgery is indicated. When a vessel ruptures, blood flows into the subarachnoid space. It is difficult to stop bleeding. An operation is required, as well as long-term rehabilitation.

The brain is an extremely important organ for human life. One of the most important factors determining its correct operation is a full blood supply to the tissues of the hemispheres, which is responsible for the most complex configuration of the vascular system in the hemispheres.

In this article, we will talk about the meaning and role of the circle of Willis, which is the most important integral part of the vascular system of the brain, consider the options for its structure and dominant pathologies that affect the functioning of the hemispheres, methods of diagnosis, the specifics and methodology of treating deviations from the norm in the VC design.

The role of the circle of Willis

A circle or a kind of ring of vessels, localized at the base of the skull, was discovered by the scientist Thomas Willis about three hundred years ago. It bears the name corresponding to the name of the discoverer. A circle of vessels is a chain of anamostoses, which form a closed polygon, visually similar to a circle or an oval, which gave it such an extraordinary name.

Ideally, the ring has a closed cycle, which directly determines the full circulation of blood and its supply to its intended purposes. VC plays a significant role in the blood supply to the brain, as it acts as a kind of natural defense mechanism that compensates for the full supply of blood to tissues in case of problems with certain arteries that make up the ring. In simple words, if one of the highways of the circle has undergone obstruction or stenosis due to unfavorable factors or congenital pathologies, the reverse side will take over the functions of the affected area, supplying blood to the brain segments suffering from blood deficiency along bypass channels.

Despite the invaluable value of the ring of vascular lines for the brain, according to the data of scientists and luminaries of medicine, not every person can become proud of the full-fledged design of the circle of Willis.

According to some statistics, no more than fifty percent of people in the world have a closed configuration of VC, while some sources indicate a percentage of no more than twenty. Based on this information, a large proportion of the world's population has a peculiar structure of the circle of Willis, not even suspecting the presence of such a deviation from the standard in the structure of cerebral vessels.

Deviations from the standard are often determined during head examinations in case of vascular health complications or other situational instrumental studies of the hemispheres. The verdict of doctors about the presence of a specific morphology of the circle of Willis in a patient makes a person look for an answer to the question of what the “variant of VC development” means and what is the threat of such a constitution of vascular ramifications. To understand what types of building the vascular pathways at the base of the brain can cause health problems, you must first delve into anatomical features VK configuration in ideal configuration. Let us consider in detail what the crown of Willis is in the optimal interposition of the vessels.

VK structure

Ideally, in order to perform their compensatory functions, the VC vessels should anastomose or connect at the original fragment of the brain, forming a closed circuit, resembling a ring in shape.

The following bloodstreams are included in the Crown of Willis complex:

The original segments of the frontal and dorsal cerebral arteries.
Two connecting lines.
Supraclinoid section of the carotid artery.

The physiological relationship between the described channels is centralized in the area of the base of the brain through the closed configuration of the Willis basin. The development of the vessels of the Willis circle, when they are combined, authorizes the hemispheres to receive blood simultaneously from the following primary sources: the internal carotid and vertebrobasilar lines. Accordingly, if one of the central highways supplying the brain has undergone deformations or disturbances, the second, with the correct development of VC, will be able to compensate for the functionality of the affected channel.

Signs of violations and methodology for diagnosing VC anomalies

Since the VC performs mainly a backup mission, minor errors in the design may not bother a person with negative symptoms until the moment when activation of his compensatory functions is required.

The need to include the elements of the circle of Willis in the work is formed under circumstances when the inconsistency of blood flow along the annular pathways develops for various reasons. Symptoms of an abnormal variant of the development of VC can be triggered by pinching of the vascular bed, appear against the background of the formation of blood clots or in the arteries that saturate the brain, with aneurysms or their rupture. Such precedents provoke the need to include “workarounds” for the supply of blood to deficient areas of the brain.

Symptoms of insufficient blood supply to the hemispheres can be varied. The most popular signs of a non-classical variant of the development of the circle of Willis are systematic manifestations of migraine, dizziness, deterioration of the competence of the thinking class, memory and attentiveness. The pathological structure of VC can also be expressed by neurological problems in the form of panic attacks, emotional instability or a tendency to neuroses.

In situations where the abnormal configuration of the circle of Willis has caused serious blood flow disturbances, the pathology can be expressed by symptoms of a stroke with possible paralysis, paresis, impaired consciousness, fainting and other symptoms characteristic of this disease.

Enlargements of cerebral vessels are most often formed in the segments of the highways of the Willis ring against the background of its modification of the nonclassical type. In such situations, precedents of hemorrhages in the subarachnoid area of the brain are possible when the integrity of the aneurysm is damaged, which in medicine is referred to as hemorrhagic strokes with dangerous consequences. In such cases, the disease manifests itself with signs characteristic of strokes, serious neurological disorders with the possible falling of a person into a coma and death.

Determine the wrong structure of the VC is possible with modern hardware techniques that allow us to investigate the structure and structure of the vascular highways of the brain.

The following studies are considered to be the main diagnostic procedures:

or computed tomography. Both methods are non-contact and provide informative data on the state of cerebral vascular branches. The first method is considered the safest for health, however, it belongs to expensive diagnostics, CT is more affordable in financial terms, while it is performed through X-ray irradiation, which can be called a "conditionally safe" process for health.
Angiography is a methodology that allows you to obtain information about the state of the bloodstream after direct injection of a contrast substance into a vessel. Angiography refers to invasive diagnostics, therefore it may have contraindications or lead to certain complications. Such a study is less modern than previous methodologies, while authorizing the assessment of the condition and passability of highways.
Doppler examination of the hemispheres is carried out by passing ultrasonic waves through the human brain, which is an absolutely safe process for health. This method has many advantages, since it allows not only to reveal the abnormal configuration of blood vessels, but also to determine the presence of pathological deformations of the channels, their localization, to assess the speed and direction of blood flow.

It is important to understand that the doctor's verdict "an unconventional variant of the development of VC" is not yet a reason for panic and the start of treatment. Certain inconsistencies with the norms in the construction of the vascular ring do not require mandatory therapy, treatment is prescribed only in situations where the incorrect configuration of the highways is unsafe for health, provokes a deterioration in the blood supply to the brain.

The need for treatment and its specificity is decided exclusively by a qualified specialist and only on the basis of the results of hardware diagnostics. To concretize the diagnosis, you may need several ways to diagnose the problem.

VK development options

Having analyzed and studied the functional significance of the VC for a person, the originality of its structure and the ways of identifying the problem, one can proceed to solving the question of what is the “variant of the development of the circle of Willis”.

It is possible to obtain a subjective picture of the developmental variant of the circle of Willis by means of angiography, MRI or CT. The image obtained by hardware methods allows you to visually examine and analyze the configuration of vascular branches, to identify deviations, if any.

The most common in medical practice are the following non-traditional VC formations:

Underdevelopment of the arteries of the connecting type. Such a pathology may not exhibit any negative symptoms throughout life, if there are no additional difficulties with the functioning of other arterial channels.
Discrepancy in the parameters of symmetrical vessels or their asymmetry about the axis. This design of the VC branching does not threaten health, since the ring has a closed shape, which allows it to fulfill its responsibilities for the blood supply to the brain. This variant of the development of the ring can serve as an explanation for the systematic migraines in humans.
Disruption of the ring sequence is the most difficult variant of the abnormal development of VC. At the same time, the absence of continuity can be either partial, due to stenosis or underdevelopment of anamostoses, and one hundred percent, characterized by the absence of connecting type lines. A variation of the design of the circle of Willis in the form of a lack of blood flow is a critical precedent for the patient.
Aneurysm of any of the VC vessels. It is characterized by protrusion or thinning of the channel shell, which can lead to deformation and rupture of the vessel, followed by hemorrhage into the cerebral zones. The most dangerous condition for the patient's life, requiring urgent medical care.

Consider the features of various modifications of the vascular ring from the point of view of medical practice, their impact on human life.

What do the various variants of the VC structure imply in practice?

For most people, the non-standard formation of VC acts as a physiological standard and may not bother a person throughout the entire life path. Health problems, due to the pathological structure of the ring, manifest themselves in situations when, against the background of unfavorable factors, the channels of the ring formation undergo deformations, which is reflected by a deterioration in blood flow.

Previously, such precedents arose mainly in old age, as a consequence of the aging process of the body, which was expressed in parallel with a decrease in the elasticity and tone of blood vessels. At the present time, the development of the circle of Willis in the form of a decrease in blood flow is characteristic of people of the younger generation as a result of negative provocateurs of a social or subjective nature.

Nonspecific versions of the VC design can act as provocateurs of the progression of life-threatening problems in the head, when compensatory capabilities decrease in the vascular highways of the hemispheres against the background of critical changes in blood circulation.

Among the most popular pathologies that are life-threatening and often found in medical practice, medicine distinguishes:

Aneurysms.

VK vascular aneurysms

Aneurysm in medicine is called the deformation of the vessel, accompanied by protrusion of the shell against the background of thinning of its surface cover. Vessels of the VC ring are considered the most susceptible to the appearance of aneurysms with non-standard variants of its design. With a small scale of formation, the patient may not feel any negative symptoms, however, the enlargement of the protrusion can provoke an infringement of the tissues of the central nervous system, which will be expressed by the following symptoms:

Deterioration of vision.
The onset of intense headaches, turning into regular migraines.

If you do not ask for help in time medical institution and not to identify the problem at this stage, further aneurysm rupture may follow, which is a direct threat to the patient's life. The following symptoms will indicate a ruptured aneurysm:

Intense stabbing pain in the head region.
Nausea with bouts of vomiting.
Short-term loss of consciousness or vision.

Ischemic stroke as a consequence of the non-standard structure of the VC

Often, the presence of breaks in the VC or the asymmetric structure of its structure is a provocateur of the progression of ischemic stroke. In the presence of additional negative factors, collateral blood flow deteriorates, and VC cannot provide adequate compensatory blood supply to the hemispheres. As a result, certain parts of the brain begin to experience a shortage of blood, and with it oxygen and useful components, as a result of which tissue death begins in the hemispheres.

The most common symptoms of a precedent are the following:

Sudden numbness in half of the body or weakness in the muscles.
Rapid degradation of consciousness, distortion of speech.
Loss of motor coordination.
Rapid growth.

Such symptoms are a harbinger of a stroke, requiring urgent hospitalization of the sick person in a medical facility.

Specificity and need for treatment of different types of VC configuration

The non-standard development of the circle of Willis, revealed as a result of a situational examination of the body, often does not require urgent hospitalization of the patient or targeted therapy. If a person is not worried about negative manifestations, then doctors will recommend him exclusively preventive measures that are aimed at reducing the risk of developing thrombosis and vascular atherosclerosis. The prevention of these diseases often consists in the elimination of negative factors of a social and subjective nature, which include rejection of addictions, rationalization of nutrition, maintaining an active life, avoiding stressful situations. In addition, after detecting a non-standard formation of the ring of Willis, the patient should be more attentive to his health, regularly undergo medical examinations in order not to miss the possible development of complications and to take urgent measures to eliminate them.

Treatment is provided only in cases where the state of the VC vessels is critical for the patient's life, mainly with aneurysms. With an existing aneurysm, the patient will have an operation: surgery to remove the formation, which is carried out by craniotomy, or the installation of a special spiral into the damaged vessel under local anesthesia if the aneurysm has not reached a critical size in terms of its parameters. V postoperative period the patient is assigned complex therapy which aims to exclude inflammatory processes, restoration of blood microcirculation and prevention of complications.

Let's sum up

The verdict of doctors that the vascular lines of the circle of Willis have a non-standard structure is not always a reason for panic. More than half of the world's population has such a "pathological" design of the VC vessels, however, they live a long life without feeling negative manifestations at the physiological level.

Such a verdict should become a certain incentive for a person to change his life activity in the correct and correct way, attentive to his health, regular preventive visits to doctors and the implementation of their recommendations.

Willis is shaped like a heptagon or heptagon. It is an important highway through which blood flows from large vascular systems - the internal carotid and vertebral arteries. Willis is forming proximal anterior and posterior cerebral arteries, anterior communicating and two posterior communicating arteries. In the walls of the vessels of the circle of Willis are laid nerve plexuses in which there are second Dogel nerve cells and receptors in free and encapsulated nerve endings; these receptors of the circle of Willis play in the regulation of cerebral circulation. In the superficial layers of the adventitia, there are islands of richly innervated glomus tissue. The vessels of the circle of Willis receive sensitive innervation from V, X pairs of cranial nerves, sympathetic innervation cervical sympathetic trunk.

Angioreceptors regulate the blood flow rate and blood pressure in the intracerebral vessels and peripheral branches of the internal carotid arteries. When irritated sympathetic nerves vasoconstriction occurs on the side of irritation and blood moves to one side of the circle of Willis. An electrocardiographic study of the activity of the heart during intracranial operations under various conditions of anesthesia and hypothermia showed that cardiovascular reflexes are carried out from the side of the circle of Willis. In addition to intravascular pressure, the physicochemical composition of the blood seems to be an adequate stimulus for the receptors of the reflexogenic zones of the circle of Willis.

Willisiev performs a "shock absorber" of pressure in the arterial cerebral system in case of sharp fluctuations in pressure and dyscirculatory disorders in the internal carotid arteries. It has been experimentally established that large vessels coming to the circle of Willis, under normal conditions, provide blood supply to strictly defined areas of the brain tissue. According to Murphy, the Willis is a potential anastomotic ring capable of opening in the shunt when one of the main vessels is blocked. Due to the large number of anastomoses in conditions of pathology in one of the systems, cerebral circulation insufficiency can be well compensated for the other. This is due to: 1) increased blood flow from the intact system; 2) the possibility of reverse blood flow through the circle of Willis in case of blockage of the carotid or vertebral artery collateral circulation is carried out thanks to the vessel of the same name on the opposite side, as well as the anastomoses of the circle of Willis in the anteroposterior direction. When the blood flow through both internal carotid arteries is closed, blood flows from the vertebral arteries. With arteriography through the Willis, blood filling of both internal carotid, anterior and middle cerebral arteries is ensured by compression of the common carotid artery in the neck and unilateral administration of a contrast agent. When the common carotid artery is compressed, the contrast agent passes from the vertebral artery through the Willis into the middle cerebral artery. When a contrast agent is injected into the vertebral artery for angiography, it fills the main artery, penetrates retrogradely into the other vertebral artery and lingers in the posterior part of the circle of Willis, since the counterpressure of blood coming from the internal carotid arteries prevents further movement in the circle.

In the circle of Willis, abnormalities in the structure of the arteries that make up the circle are often observed (in almost 50% of cases). According to I.F.Krupa and N.N. This is confirmed angiographically. Anomalies of the circle of Willis (a decrease in the anterior and posterior connecting arteries or their asymmetry, aneurysms) sometimes cause insufficient blood supply to the brain and limit compensatory possibilities in case of impaired blood supply as a result of blockage or rupture of any of the great vessels.

By the method of angiography in the circle of Willis, a transient angiospastic blockade of blood circulation was detected, causing hypertension, dynamic circulatory disorders of the brain. Blood circulation in the circle of Willis can also change with congenital or acquired aneurysms as a result of their rupture or dyscirculatory disorders of the reflex order. Congenital aneurysms of the circle of Willis occur at the site of the origin of the posterior communicating arteries from the trunk of the internal carotid artery or in the region of the anterior communicating artery. In the posterior part of the circle of Willis, aneurysms are relatively rare. Aneurysms are mainly observed in young people, in women.

Congenital anomalies in the structure of the circle of Willis (asymmetry of the posterior communicating arteries, the absence or sharp decrease in the size of the anterior and posterior communicating arteries and cause an inadequate blood flow in the circle of Willis and impede blood circulation in the event of impaired compensation, which is usually developed gradually from the very early age... Decompensation occurs when a major vessel ruptures or when an excessive load on vascular system... Unlike intracerebral vessels, there is a pressure difference in the arteries of the circle of Willis, since it is not balanced by the pressure of the brain tissue. Insufficient blood supply at a young age can manifest itself periodically with headaches (migraine), sometimes a sensation in the head and worsening of the condition with sudden changes in the position of the head and compression of the neck in the area of the carotid sinus.

Aneurysms of the circle of Willis developing in persons of mature age are caused by a pathological vascular process that causes destruction of the vascular wall (atherosclerosis, syphilitic endarteritis, infectious vasculitis). In the etiology of late developing aneurysms, congenital malfunction of the arterial system and the influence of trauma or progressive cerebrovascular disease are important.

Aneurysms of the circle of Willis cause various clinical syndromes: a) discirculatory disorders with a slowly growing aneurysm and with the development of a dissecting aneurysm; b) pseudotumorous syndrome when the aneurysm compresses the surrounding cranial nerves and medulla; c) hemorrhagic extracerebral basal syndrome with rupture of an aneurysm and hemorrhage into the subarachnoid space at the base of the brain.

Symptoms of aneurysms of the circle of Willis are determined by the localization, size and nature of the pathological process in the aneurysm (compression, rupture, etc.). Aneurysms cause recurrent headaches and nerve compression syndrome.

With aneurysm of the posterior communicating artery (the posterior communicating artery supplies blood to the anterior third of the cerebral peduncle, gray tubercle, luis and head is localized in the temple area, there is double vision (recurrent paralysis of the oculomotor nerve). A picture of basal chronic meningitis appears (sometimes syphilitic meningitis is assumed) ...

With aneurysms of the anterior communicating artery (feeding through small branches of the chiasm, septum pellucidum and anterior commissure), a basal-frontal syndrome develops with symptoms of circulatory failure in the anterior cerebral artery. Sometimes the sense of smell on the side of the aneurysm (detected by olfactometry) and vision (damage to the chiasm) are impaired. With blockage of the anterior communicating artery, softening of both frontal lobes sometimes occurs.

An aneurysm of the internal carotid artery near the origin of the posterior communicating artery causes a syndrome similar to aneurysms of the posterior communicating artery. A triad of symptoms is characteristic: headache, sometimes in ophthalmoplegic migraine, in eyeball or the inner part of the orbit, compression of the oculomotor nerve (recurrent nature). Dyscirculatory disorders are observed in the distal branches of the internal carotid artery. Sometimes there are phenomena from the orbital artery. A combination of pain in the innervation of the first branch is characteristic trigeminal nerve, damage to the oculomotor nerve and noise in the head.

Crises with aneurysms of the circle of Willis are manifested in short-term paroxysms caused by the dissection of the wall of the aneurysm and leakage of blood along the wall (dissecting aneurysm) without damaging the outer shell. Symptoms: vomiting, fainting, headache localized in the area of the eyeball and, less often, in the temple.

Vascular defects, congenital and acquired, for the most part, are extremely dangerous in nature. Within a certain time (on the order of several years, less often for a much longer period), pronounced symptoms of insufficient blood flow in a particular area begin, risks of critical, urgent conditions appear.

Damage to the brain, cardiac structures is especially common in the practice of specialists.

Both options are equally threatening. In the first case, the likelihood of developing a stroke rapidly "jumps". In the second - a heart attack.

Without therapy, the outcome is negative, when the moment comes is a moot point. The body also has compensatory mechanisms to prevent sad scenarios, or at least slow down the progression of the pathological process.

The circle of Willis is a chain of arteries closed in a radial structure, a ring localized in the occipital region of the brain.

Globally speaking, this anatomical system is represented by the carotid and vertebral arteries, which are connected by special collateral branches (neighboring, not so large vessels), which, among other things, perform a service role: to provide uninterrupted nutrition of the brain tissues.

The circle of Willis (abbreviated VC) is a special mechanism for compensating for disturbances in the trophism of nerve tissues. Normally, it must work and replace the affected vessels, create constancy in the amount of incoming oxygen and nutrients.

However, the structure does not always fully implement its functions. Then critical violations cannot be avoided.

As it was said, constancy and continuity are provided normally, and deviations from it are extremely common.

According to research, the standard, "textbook" variant of the development of the circle of Willis is a relatively rare phenomenon, it occurs in only a quarter of clinically recorded cases.

Therefore, in the event of an "emergency" situation for the body, the further course of a stroke, acute cerebrovascular accident or chronic pathologies will depend on the type, structure of such a mechanism.

The "safety margin" for different types of development turns out to be their own, according to this criterion, the probability of compensation is estimated at prehospital stage, during diagnostics or routine examination.

As for the functions of the named structure, they have already been partially named. It is worth specifying:

Providing constant uninterrupted power supply to nerve tissues

All major arteries of the brain converge. This is necessary to create a constant, unchanging blood flow.

The Willis circle works, as they say, with a margin, because it also has a second important task.

Rapid redistribution of blood supply pathways

Including the central nervous system during the development of critical situations: stroke or.

Factors such as the rate of recovery, the depth of neurological deficit, the likelihood of death and the area of damage to nerve tissues depend on the quality and shape, the anatomical structure of this radial formation.

Also, the circle of Willis is able to compensate for eating disorders during the course.

The change is provided due to the redistribution of hemodynamics or the formation of an external vascular network, which will cover the brain's need for a part of the deficit.

These are the so-called collaterals. In some cases, they cannot form quickly enough. Against the background of pathologies of connective tissue, diabetes mellitus... Then the risk of fatal bleeding or other complications increases.

Thus, the Willis circle works as a compensator, a regulator of cerebral trophism, acts as a defender of normal nutrition, and prevents death from a critical hemodynamic disturbance.

As already mentioned, it is possible to talk about the norm only conditionally, because the classic variant of development is rare, in 25% of cases or a little more. The authors do not agree, there are certain discrepancies.

In all possible cases, developmental anomalies of the circle of Willis are congenital. The shape and type are laid even in the early periods of pregnancy, gestation.

The changes are not always due to the behavior of the mother or the influence of negative environmental factors: radiation, toxins, metal salts, infections, and others.

In the absence of any violations of the quality of trophism, the speed of blood movement, they speak of a variant of the physiological norm. Such situations require neither treatment nor specialized care.

But sometimes it would be nice to visit a therapist or cardiologist for a routine check-up (once a year or more often if desired).

Normally, the structure of the circle of Willis is represented by a group of structures: anterior, posterior, connecting arteries, which provide the movement of blood through the tissues from the carotid and vertebral arteries.

In the system, they form a ring, the movement of fluid connective tissue is cyclical, the volumes are larger than what is required under normal conditions.

Thanks to this, it is possible to compensate for violations if necessary.

Abnormal development options

It is possible to talk about pathology or any "abnormality" with a great deal of convention. Research is eloquent in favor of the same conclusion, although not always directly.

It is necessary to take into account the state of health and the rate of trophism in the brain of a particular patient. The development of the circle of Willis most often follows the type of absence of a part of collaterals; these are relatively easy variants of deviation.

But hypoplasia, underdevelopment of the main vessels can play a sad role.

What forms of anatomical structure exist:

Absence of a connecting artery in front. It acts as a jumper connecting the cerebral vessels. Due to this structure, a more rapid movement of blood occurs.

The absence, however, almost never gives any symptoms, because the body has the ability to compensate for the conditioned disorder on its own.

This anomaly is relatively rare, accounting for no more than 2.5% of the total mass of cases.

Absence of one of the posterior communicating arteries. Left or right ZSA. Structures provide communication of larger vessels, the variety is relatively frequent. It is found in 13% of clinical situations.

Slightly more often, the left connecting artery is absent. Why this is so is not exactly known.

There is a mixed case when both the anterior and one posterior communicating artery is absent. This is an extremely rare disorder. It is observed in 1% of cases.

It is accompanied by discirculatory changes, in certain conditions.

The nutrition of the brain is not intense enough, therefore, any violation: whether it be atherosclerosis or spasm of the arteries, is accompanied by changes in a functional nature, a passing neurological deficit.

And in the course of chronic disorders, also structural gradual changes that create permanent failures in the work of the central nervous system. This form of anomaly must be treated.

An extremely common option is trifurcation: the departure of the structures of the posterior cerebral artery immediately from the carotid artery. The prevalence is almost 20-25% of the total mass.

There are many manifestation options: discirculatory encephalopathy, stroke, migraine, and others.

The absence of symptoms is possible with sufficient compensation for nutrition in the neighboring vessels, the branching of the original circulatory network.

In any case, such patients must be carefully monitored so as not to miss the moment of transition of a shaky norm to pathology.

Another mixed version of the open circle of Willis is simultaneous trifurcation in the absence of the anterior communicating artery (bridge). It is found in 2-3% of situations.

It gives about the same symptoms, but the blood supply to the brain is worse and the risks of decompensation are almost twice as high.

Recovery involves taking medications to accelerate cerebral blood flow and prevent stroke. Surgery is possible.

Absence of both PCA (posterior communicating arteries) and PSA (anterior communicating artery) at the same time. An open circle of Willis develops when the rings do not come out of the anatomical structures.

Collaterals provide compensation for the need for redistribution of trophism. In the same case, this option is impossible: carotid and vertebral vessels are not connected and exist in isolation, which creates huge risks with the slightest change in the quality and quantity of incoming blood.

The shape is not much different, in which there is an anterior, but both posterior communicating arteries are absent. The condition is approximately identical, there is not much difference.

Anterior trifurcation leads to the departure of both collaterals of this localization from the same carotid artery. Which shouldn't be. Hence, the increased risks of negative phenomena in the event of a malfunction of this particular vessel. Immediately, two connecting structures cease to perform their functions, and blood flow asymmetry develops.

Hypoplasia. It is relatively common. It is presented in the form of a decrease in blood flow in one or both of the connecting arteries. Localization has no of great importance in terms of understanding the essence - the artery is too small in diameter, underdeveloped, and therefore unable to perform the functions assigned to it.

Such a situation is especially dangerous with the defeat of the main branches, which are considered fundamental: the carotid and vertebral arteries.

Based on the location, we can talk about many different symptoms: from headaches, migraine attacks to stroke without prior manifestations. Spontaneous acute disturbance of cerebral blood flow.

Aplasia. The complete absence of any part of the circle of Willis. Occurs in 5-12% of situations. It is accompanied by critical disturbances with minimal changes in the quality of trophism.

This development option is extremely unstable, urgent treatment is required, immediately after the problem is identified.

There are also species with duplication of individual collaterals: doubling. As a rule, both vessels involved in the formation of the anomaly are equally underdeveloped, which, however, does not interfere with the provision of normal nutrition.

These are only a part of the possible types. They are the most common. All others are derivatives of those named.

If the Willis circle is closed, the compensatory function is mostly maintained at an adequate level, therefore, even in the case of the development of an acute malnutrition of nerve tissues, transient ischemic attack, atherosclerosis, other diseases, there are good chances for a quick recovery.

Diagnostics

The examination is carried out under the supervision of a specialist in vascular surgery... Involvement of a neurologist is possible.

Activities are mostly standard and need to be carefully assessed anatomical structure Circle of Willis.

Angiography. Essentially, an X-ray with contrast. Introduced special drug, which accumulates in the blood and enhances the pattern. Then the doctors take a series of pictures and, according to the results, evaluate the nature of the structure of the ring-shaped structure. It is considered an affordable and relatively simple diagnostic method with a minimum of contraindications.
Doppler ultrasonography of cerebral vessels. It is required to assess the speed and quality of blood flow in the cerebral structures, it is used as part of a functional examination. Appointed in all cases.
MRI. To identify complex forms of anomaly. This is perhaps the most informative technique among others. The most safe, not creating a load on the body, not accompanied by painful sensations... But the cost of research is on average more expensive than analogs. Therefore, they resort to this method when others have not given effect.
Perhaps the appointment of invasive, selective angiography.

Activities can be adjusted during the survey, supplemented by other techniques. The issue is decided at the discretion of a specialist.

When is treatment needed?

Therapy is not always required. Among the options that differ in danger are:

Complex forms of the absence of connective arteries, collaterals. In this case, the risks of migraine, stroke, discirculatory encephalopathy increase. Correction is required to prevent violations that have not yet occurred. This is the main direction.
Hypoplasia of the vertebral arteries, and other structures of the Willis circle. Requires immediate medical attention, because it poses a threat of ischemia and early development of a stroke. It is necessary to prevent the deposition of cholesterol plaques, arterial stenosis.

Lack of closure of the ring of vessels. Therapy is aimed at preventing complications and correcting symptoms. The open form of the anomaly is considered especially dangerous. The most threatening of them all. Therefore, treatment continues for a lifetime under the vigilant supervision of doctors.

Elimination of the structural violation itself is a key task. Others are aimed at restoring normal functional activity of the brain.

Drug therapy

Symptomatic correction is required, for example, within the framework of migraine, its frequent attacks. Encephalopathy, neurological deficits in this regard.

Medications of several types are prescribed:

Anti-inflammatory non-steroidal origin, Ketorol, Nimesulide, Diclofenac. Others. In addition to the main effect, they have the ability to relieve pain, which is used in therapeutic practice.
Antispasmodics. Drotaverine, Papaverine, other names. They stop vascular stenosis, excessive abnormal narrowing of the arteries. In most cases, medication is prescribed as a symptomatic measure. To fix the problem here and now.
... Accelerate metabolic processes in the brain. Prevents early destruction of cerebral structures. Such names as Phenibut, Glycine are used.
Cerebrovascular. To accelerate blood flow in the central nervous system... The technique allows you to restore trophism, eliminate ischemic phenomena. Piracetam, Actovegin. The latter has an antianginal effect. Reduces tissue oxygen demand, optimizes nutrition and metabolic processes.
Application is possible. Anavenol, others in the framework of strengthening the vascular wall. Restoration of its elasticity, resilience and ability to withstand, including increased stress.

Lifestyle change

A big role is given to giving up bad habits, changing the way of life.

The exclusion of smoking, alcohol intake is shown. It is also undesirable to drink coffee, it is better to replace it with herbal decoctions or chicory.
In addition, the use of salt is limited to 5-7 grams per day, so as not to cause an increase in blood pressure.
Nutrition involves the inclusion of plant foods in the diet. Exclusion of semi-finished products, smoked meats. Also less fried, salty, fatty.

You need to eat meat, but it is better to limit yourself to some varieties of poultry: turkey breast, chicken.

Surgical correction

In difficult cases, surgery is indispensable. The task is to restore the normal structure of the circle of Willis in a certain part.

For example, creating a bypass path for blood flow (shunt), mechanical expansion of the artery lumen (stenting, ballooning).

Often a complication of the abnormal development of the annular structure is the aneurysms of the vessels that are part of the vessels: saccular expansion of the walls, which can break through at any time. It is also an absolute indication for surgery.

The choice of tactics falls on the shoulders of the doctor.

Finally

The circle of Willis is a system of closed cerebral arteries that provide constant nutrition to the cerebral structures, even in emergency cases.

But for the most part, it is not developed at all in the way that doctors indicate within the framework of the clinical norm.

Depending on the type of formation, the risks of pathologies of the ischemic plan will be different. Most of the patients are unaware of the problem. Often in such situations one speaks of a variant of the clinical norm.

Sometimes you can see a statement of the fact that the circle of Willis is open. What this means, good or bad, is very difficult to determine without appropriate research and additional signs. The structure of the arteries in each person can be individual in nature, and at the same time be within the normal range. Cardiac arteries are assumed to be among the normal at once 3 variants of blood circulation, which are found only with appropriate studies. The situation is approximately the same with the circle of Willis. The location and development of this crown of anastomoses in only half, or even a quarter of adults, corresponds to the medical norm of development.

The circle of Willis - what is it

Almost 300 years of anatomical research, plus the opportunities obtained with the development of modern instrumental studies - Doppler ultrasound, and several types of angiography, made it possible to establish that the circle of Willis in half or in most cases does not correspond to the medical norm. However, recently it is not customary to talk about an absolute norm, because in the body of each person, individual structural features may be present.

This applies to any operating system, including arterial blood flow. Not everyone has the so-called classic arterial ring. And that means. that in many people, the peculiar development of the anastomoses ring can lead to various disorders or negative sensations.

Nature has provided the adult with the possibility of interrupting the cerebral circulation. Since it belongs to vital organs, its blood supply should not be interrupted. For this purpose, at the base of the brain (if quite precisely, then in its subarachnoid space, between the soft shell of the GM and spinal cord), the arteries are located.

What functions is responsible for

The main purpose of vascular education is to constantly provide the brain with blood. It should occur with a wide variety of functional injuries and failures caused by serious diseases, arterial occlusions or damage to them. This is a kind of fuse chain, in which the possibility of blood flow through the arteries, which are normally responsible for other functions, is provided.

The responsibilities of the departments that make up the Circle of Willis include:

provide the brain with the necessary nutrition in case of damage or congenital anomalies of the arteries;
to maintain the functionality of the GM in case of spasms or abnormal variants of the location of the vessels;
prevent damage to nerve tissue if the activity of the cervical arteries is disrupted;
avoid the development of foci of oxygen starvation by redirecting blood to such a site.

Fact!

Only the system that is formed without violations can normally cope with its purpose. Half, sometimes ¾ of all people have deviations from the physiological structure. The presence of such anomalies is associated with intrauterine development, which humanity has not yet learned to manage.

Possible pathologies

In medicine, structural deviations are diplomatically called the variant anatomy of the circle of Willis. There are many of them, and not every person has only one, sometimes there are several of them at once. The most common of these is trifurcation. It is found in that part of the internal carotid artery, which is called supra-wedge-shaped, it is posterior (when 3 cerebral arteries begin from this fragment) and anterior - both anterior cerebral arteries begin from the carotid artery. Aplasia (absence due to congenital malformations) of the posterior communicating artery is often noted. This option can be with both PCA, and with all connecting arteries, and even with the main artery.

If the Willis circle is open - good or bad

If the Willis circle is open, this is a developmental anomaly that caused a negative effect on the fetus. For some reason, there is a deviation from the scenario envisaged by the nature, and the formation of the choroid plexus leads to the asymmetry of the VC.

The question of what to do with such deviations arises with the development of diseases, and before that (sometimes up to deeply old age), no one even suspects that he has it at all. Aplasia, hypoplasia or trifurcation are detected during research by special diagnostic methods. The need for it is revealed against the background of the development of diseases, but sometimes a negative scenario develops suddenly.

Interesting!

The development of negative states is typical in old age, when the compensatory ability inherent in an open circle weakens. When he is unable to normalize arterial blood flow, and complications or diseases appear.

Effects

VC development anomalies never lead to positive processes. This is a failure in the functional purpose of an organ or system, which nature is able to compensate for up to a certain time. Asking whether it is good or bad usually begins when a disease develops, and modern medicine has not yet learned how to treat anomalies in the structure of blood vessels.

She only heals diseases that become their consequences. The most common of these are aneurysm and ischemic stroke. Treatment of an open circle is not carried out, and only if there are consequences - rupture of a vascular aneurysm and subarachnoid hemorrhage, or ischemic stroke, there is a need for surgical (ligation of the aneurysm) or conservative treatment, as with any subarachnoid hemorrhage.