The largest vessel that provides blood supply to the human brain is the middle cerebral artery, which transports oxygen and nutrients to most areas of this most important organ. Next, we will get acquainted with its structure and possible pathologies that occur when its functioning fails. In addition, we will learn how the diagnosis and study of the work of such an important brain element as the middle artery is carried out.
Building
The middle cerebral artery is the largest of the branches of the internal carotid artery and its direct continuation. It is included in the depth of the lateral sulcus of the brain and goes first outwards, and then upwards and slightly backwards, reaching the upper lateral part of the hemisphere. In the direction of its course, it is topographically divided into several parts:
- On the wedge-shaped part - fromsection of its origin before descending into the lateral sulcus.
- To the insular part, which goes around the islet and runs in the very depths of the lateral groove.
- On the end part, which emerges from the lateral groove to the region of the upper lateral surface of the hemisphere.
The wedge-shaped part of the artery is the shortest. Its distal boundary after descending into the lateral sulcus is considered to be the region of origin of the frontal basal artery. From the wedge-shaped section, the central anterolateral arteries depart, which penetrate through the perforated substance, then they are divided into lateral and medial branches, heading upward. The lateral branches supply blood to the outer part of the lenticular nucleus along with the posterior parts of the outer capsule. The medial branches, in turn, approach the internal parts of the pale ball, and in addition, to the body of the caudate nucleus.
Fetal middle cerebral artery
The main vessels that provide blood to the body of a growing fetus are the uterine and ovarian arteries. Branching into smaller vessels towards the inner layer of the uterus, they transform into spiral arteries that carry blood to the intervillous space - this is the place where mother and baby exchange blood.
What are the normal parameters of the fetal middle cerebral artery? This is a frequently asked question.
The study of blood flow in it is of an applied nature. To determine the indicators of the middle cerebral artery of the fetus, color doppler is used, followed by Doppler measurements. Normal in the second and third trimesters of pregnancythere is a gradual decrease in the index of vascular resistance and an increase in the average blood flow velocity.
With fetal hypoxia, centralization of blood circulation is observed, which leads to an increase in velocity in the cerebral arteries and, accordingly, a decrease in the resistance index. With its increase, we can talk about intracerebral hemorrhages.
Doppler norms in the middle cerebral artery of the fetus depend on the gestational age. They are listed in the table below.
| Gestational age, weeks | Mean blood flow velocity, cm/s | Ripple index |
| 20 | 18.2 - 26.1 | 1.35 - 2.33 |
| 21 | 19.4 - 29.1 | 1.42 - 2.36 |
| 22 | 20.7 - 32.2 | 1.45 - 2.39 |
| 23 | 22.3 - 35.1 | 1.48 - 2.42 |
| 24 | 23.5 - 38.2 | 1.50 - 2.43 |
| 25 | 24.9 - 41.2 | 1.54 - 2.47 |
| 26 | 26.5 - 43.9 | 1.50 - 2.41 |
| 27 | 27.8 - 47.4 | 1.50 - 2.43 |
| 28 | 29.1 - 51.8 | 1.51 - 2.47 |
| 29 | 30.5 - 54.1 | 1.54 - 2.48 |
| 30 | 31.7 - 56.2 | 1.54 - 2.46 |
| 31 | 33.3 - 59.4 | 1.50 - 2.45 |
| 32 | 34.6 - 62.4 | 1.50 - 2.42 |
| 33 | 35.8 - 65.3 | 1.45 - 2.38 |
| 34 | 37.2 - 68.4 | 1.42 - 2.35 |
| 35 | 38.5 - 71.3 | 1.41 - 2.33 |
| 36 | 40.2 - 74.1 | 1.35 - 2.29 |
| 37 | 41.4 - 77.3 | 1.31 - 2.25 |
| 38 | 42.6 - 80.3 | 1.26 - 2.20 |
Separation of the vessel
The middle cerebral artery divides into separate branches:
- On the deep branches that go directly from the very beginning of the vessel, providing blood supply to a large proportion of the subcortical regions and a significant portion of the internal capsule.
- But cortical and subcortical. They include all significant vascular branches that are responsible for the normal blood supply to a larger area of the brain.
The resulting ischemic stroke in the basin of the middle cerebral artery immediately affects facial expressions and the ability of a person to move normally. The blockage of the artery that has occurred directly affects the ability of a person to freely move his upper limbs. Next, consider the possible pathologies that occur when the blood flow of the middle cerebral artery is disturbed.
Possible pathologies
The largest cerebral artery supplies most of the brain with blood, and very often it happens that various pathologies occur in its pool, which cause depletion of oxygen in the brain tissues in nutrition.
Normally, blood flow in the middle cerebral artery is normal.
To the mostcommon diseases that affect the internal vascular walls include:
- The appearance of atherosclerotic changes associated with the formation of fatty and cholesterol plaques in the lumen of the arteries.
- The occurrence of various types of embolisms.
- The appearance of disorders in the structures of the arteries that lead to aneurysm.
- Development of thrombosis.
Occlusive changes in the carotid arteries can cause a cerebral infarction in the absence of a pronounced painful change in other vessels. But in most situations, a cerebral infarction occurs against the background of a combination of diseases that affect the middle and carotid cerebral arteries and its basin.
The appearance of occlusive processes in the arterial trunk, along with their scale, level and location, as well as the possibility of maintaining the collagen type of blood supply, draw a general clinical picture. At the same time, in situations of occurrence of pathology above the region of the branch of large vessels, a total form of damage to the entire basin of the middle cerebral artery is noted. The pathology above the branches can affect certain areas of the subcortical part and the white matter area.
Cerebral infarction and left branch of cerebral artery
Total cerebral infarction affects the following parts:
- Posterior frontal lobe.
- The vast majority of the anterior and posterior gyri.
- Significant area in the parietal and temporal part.
- Inner capsule along with semi-oval area.
Defeat back areasbasin of the right or left middle cerebral arteries is likely only in the presence of a cumulative disease of the middle artery and its posterior branch. A total heart attack leads to the following disorders in the human body:
- Development of hemiplegia. In this case, patients lose control over their conscious movements with different limbs.
- The occurrence of hemianesthesia. Against this background, the patient may stop feeling certain pain sensations in a particular half of the body.
- Development of hemianopsia. At the same time, there is an absolute impossibility to visually distinguish individual objects in one's field of vision.
The resulting stroke within the basin of the left branch of the cerebral artery leads to a serious impairment of speech and anosognosia. The patient ceases to realistically assess the seriousness of his illness, which often makes it difficult to provide subsequent medical care.
Ischemic stroke in the basin of the right middle cerebral artery
Most strokes tend to develop in the basin of the middle artery. They are characterized by homonymous hemianopsia, which indicates lesions of the visual radiation. Eyeballs in a stroke are turned towards the affected hemisphere. There may be weakness of the facial muscles of the lower region of the face. In addition, the patient develops spastic hemiparesis (in this case, the hands of a person suffer more than the legs). Muscle tone in a paralyzed limb may initially decrease, but spasticity develops after a few days.
What are other signs of a stroke in the basin of the middle cerebral artery?
Sometimes sensory and motor impairment is limited to contralateral movements of the arm and half of the face, while the legs and torso hardly suffer. In case of damage to the dominant hemisphere, the onset of motor and sensory aphasia is possible. In ischemic stroke of the middle cerebral artery against the background of damage to the parietal lobe of the non-dominant center, a complex violation of sensitivity occurs along with a disorder of perception. The defeat in the right hemisphere is often accompanied by confusion, and the left - the onset of depression in the later stages of the disease.
Cerebral edema can be caused by narrowing and occlusion of one or both middle cerebral arteries in a stroke. The consequence of all this is cortical blindness and hemianopia. With the development of occlusion of the cervical region of the internal carotid artery, blood enters the region of the anterior cerebral artery through the connecting anterior branch from the opposite side. Due to this, stroke is prevented in the medial surface of the hemisphere and in the frontal lobe. Blood in the region of the posterior cerebral artery comes from the region of the vertebrobasilar system. In this regard, in the presence of occlusion of the carotid internal artery, a stroke usually develops within the basin of the middle cerebral branch.
Possible pathologies: atherosclerosis
Being the largest, this cerebral artery is at risk of pathological atherosclerotic changes. Particularly dangerous is the stenotic syndrome, against which the lumen of the artery can becompletely covered. The anostotic course of the disease leads to the growth of cholesterol growths along the length, contributing to a decrease in the amount of blood transported to certain areas of the brain.
The growth of lipoid formations on the walls of this artery occurs over a fairly long period. In the vast majority of situations, years pass until the size of the plaques becomes critical and blocks the normal nutrition of brain regions. At the initial stage of atherosclerosis, plaques can only be found using special diagnostic equipment, and given that patients do not always have severe symptoms of the disease, their presence remains simply hidden for a long time.
The initial stages of atherosclerosis, which affect the large arteries of the brain, are characterized by a slight deterioration in the general well-being of the patient. But in the course of an increase in lipoid deposits, the clinical picture is more pronounced, and against this background, the general symptoms of the pathology intensify. A person feels discomfort with a sharp movement of the head, and in addition, with increased loads. There are sharp dizziness, especially with a sudden decrease in blood pressure.
At this stage, it is extremely important to immediately consult a doctor. Proper diagnosis in combination with the prescribed treatment method will certainly help to avoid the occurrence of consequences in the form of a stroke in different cerebral hemispheres or a heart attack that affects the entire region of the middle cerebral artery along withwith her collage mesh.
In most situations, the initial stages of atherosclerosis are successfully treated with medications that improve overall blood flow in the brain. In addition to prescribing medications, doctors provide advice on coordinating the patient's lifestyle with the maximum exclusion of factors that provoke the number of sclerotic growths. In neglected situations, effective assistance to the patient is possible only in the hospital of surgical departments.
Aneurysms
Any aneurysms of such a site as the middle cerebral artery are a direct consequence of the disease of its walls, in which the norms of the tissue structure are violated. In this case, the artery is no longer a triple layer of tissue from muscles and membranes. The aneurysm includes only one layer of connective tissue, which is not able to ensure the full functioning of the artery. When there is a violation in the structure of the vessel, a protrusion of its walls appears, in which they often break with the formation of hemorrhage into the adjacent tissue.
The most dangerous is the ingress of blood into the region of the arachnoid brain space, in which patients can experience the most severe consequences. The increased risk category includes the male part of the middle-aged population - those who have a hereditary predisposition to the occurrence of structural vascular disorders.
The left and right middle cerebral arteries are affected by wall aneurysms in 25% of the total number of blood flow pathologies. ATIn most expansion situations, along with arterial ruptures, they occur at bends in which weakened walls receive excessive dynamic pressure. Symptoms of a ruptured cerebral artery aneurysm develop very rapidly, characterized by the following signs:
- Patients complain of sudden and severe pain in the head, which is the result of excessive workload, pressure surge or severe stress.
- Occurrence of partial aphasia against the background of damage to the left hemisphere of the brain, while paralysis of the upper limbs occurs for a while.
- Convulsive seizures are not excluded, against which the hands can assume an unnatural position (in this case we are talking about thalamic hand syndrome).
- Spasms of blood vessels lead to increased headaches, which may be accompanied by nausea and vomiting. The pain syndrome may acquire a burning sensation.
In twenty percent of cases, patients with a ruptured cerebral artery aneurysm have an atypical development of the clinical picture. As a result of all this, the doctor sometimes makes a mistake with the diagnosis and the patient is placed in a non-core department, therefore, in relation to him, they are late with the provision of emergency care. In this regard, the percentage of disability of patients and fatal outcomes with improper treatment is quite high.
Diagnosis
Timely determine the occurrence of various pathologies of the artery in question, which feeds the brain, will help the study of its condition in a specialized medical center. Feeling regularchanges in well-being, which is expressed by headaches or dizziness, numbness of certain areas of the limbs or a decrease in the ability to remember elementary things, spasms of certain muscle groups and problems with speech, the patient must definitely go to see a neurologist. The doctor will hear all the patient's complaints, and he will be assigned a comprehensive examination of the vessels that feed the brain. For these purposes, various modern techniques can be used:
- Magnetic resonance imaging allows to detect atherosclerotic changes on the walls of blood vessels.
- Carrying out dopplerometry makes it possible to assess the intensity of blood flow in the artery. With the help of this type of study, it is possible to study the state of the vessels in the patient.
- Performing an x-ray. With the help of this examination, the walls of the arteries are analyzed, and in addition, acute atherosclerosis is detected along with arterial aneurysms. X-rays provide information about the condition of the cerebral region of the middle cerebral artery.
Contrast radiography makes it possible to assess the extent of the affected area of the vessel. Thanks to him, the left median cerebral artery is examined, as well as the right one, and in addition, the condition of its branches is assessed.
Treatment and support
Timely detection of pathologies of this artery will help to avoid the serious consequences of its diseases in the future. Should not be treatedchanges in their well-being without attention. The fact is that recurring symptoms of insufficient blood supply to the brain in the form of vasospasms or deterioration in peripheral vision require immediate specialist help.
It is possible to avoid most of the pathological processes in the arteries of the brain, subject to certain recommendations. Indeed, a significant proportion of pathologies is the result of factors that a person regularly encounters. Their complete exclusion from life helps to avoid the occurrence and development of many vascular diseases. To support the arteries of the brain in a he althy state, a person needs:
- Diversify everyday life with feasible physical activity.
- Ensure that there is no overload with excessive work. It is necessary to try to rest properly.
- Quit smoking and drinking alcohol.
- Monitor your own weight, normalize nutrition.
- Eat plant-based foods. At the same time, the consumption of fatty meat dishes is reduced.
- In case of detection of sclerotic pathologies in the artery, it is necessary to carefully follow all the recommendations of a specialist.
It is also important to remember that a violation of the speed in the middle cerebral artery of blood movement (blood flow) is most rarely the result of previous diseases. In addition, problems with the vessels of the brain are not inherited by people. In most situations, developing stroke with infarction of certain parts of the brain occurs inas a result of the wrong way of life, which in modern people is filled with excessive stress shocks and a frantic rhythm.
