Anatomy of the central nervous system and sense organs. Ventricles of the brain

Third (III) ventricle, ventriculus tertius (see Fig. , , , , , , , , , ), unpaired, located in the median sagittal plane and communicates with the lateral ventricles and with the IV ventricle.

The cavity of the III ventricle is slit-like, limited by 6 walls: upper, anterior, lower, posterior and two lateral.

superior wall of the third ventricle vascular base of the third ventricle, tela choroidea ventriculi tertii(see fig.), is a formation of two plates - the upper, dorsal, lying under the arch and the corpus callosum, and the lower, ventral, facing the cavity of the third ventricle. Loose connective tissue is located between both plates. In it, two internal veins of the brain pass on both sides of the midline, which, having received blood from the veins of the thalamus and striatum, the veins of the transparent septum and choroid plexus, and the lateral ventricles, flow into the large vein of the brain. From the ventral plate, a series of villi protrude into the cavity of the third ventricle, which form choroid plexus of the third ventricle, plexus choroideus ventriculi tertii. Anteriorly, at the interventricular opening, it connects to the plexuses of both lateral ventricles.

The lateral walls of the third ventricle are formed by the medial surfaces of the thalamus. Vertical bundles pass under the ependyma of the lateral wall periventricular fibers, fibrae periventriculares connecting the medial group of thalamic nuclei with the hypothalamic nuclei.

In front, the cavity of the III ventricle is limited by the columns of the fornix and the anterior commissure adjacent to the posterior surface of the end plate. Between the anterior tubercle of each thalamus and the columns of the arch lying in front, a interventricular foramen, foramen interventriculare connecting the third ventricle with the lateral.

Ventral to the posterior commissure is an accumulation of specialized ependyma cells - tanycytes. These cells perform a secretory function and are involved in the transport of hormonal and mediator substances from the adjacent tissue into the cerebrospinal fluid and vice versa. This section of the ependyma of the third ventricle is designated as subcommissural organ, organum subcommissurale.

There is a small, triangular depression between the divergent columns of the arch and the anterior commissure. It also contains a cluster of specialized ependyma cells - subfornical organ, organum subfornicale.

At the site of attachment of the end plate to the optic chiasm, a visual recess, recessus opticus. In the early stages of brain development, it is the terminal section of the cavity of the brain (neural) tube.

The lower wall, or bottom, of the third ventricle is the formation of the hypothalamus, which lies at the base of the brain.

The posterior wall of the third ventricle is mainly epithalamic adhesion, commissura epithalamica. It is a curved plate protruding into the cavity of the ventricle and consists of transverse fibers. Below it is pineal recess, recessus pinealis, passing into the cerebral aqueduct, connecting the III ventricle with the IV, above it - suprapineal depression, recessus suprapinealis, and even higher - soldering leashes.

The human brain is a complex and amazing structure, all the secrets of which scientists have not yet unraveled. One of the most interesting mechanisms of the functioning of the nervous system is the process of formation and circulation of CSF (cerebrospinal fluid), which is carried out with the help of the 3rd ventricle of the brain.

3 ventricle of the brain: anatomy and physiology

The third ventricle of the brain is a thin slit-like cavity bounded by the visual tubercles of the thalamus and located in the diencephalon. Inside the third ventricle of the brain is lined with a pia mater, branched choroid plexus and filled with cerebrospinal fluid.

The physiological significance of the 3rd ventricle is very high. It provides an unhindered flow of CSF from the lateral ventricles to the subarachnoid space for washing the brain and spinal cord. Simply put, it provides circulation of cerebrospinal fluid, which is necessary for:

regulation of intracranial pressure;
mechanical protection of the brain from damage and injury;
transportation of substances from the brain to the spinal cord and vice versa;
protect the brain from infection.

3 ventricle of the brain: the norm in children and adults

A normally functioning liquor system is an uninterrupted and well-coordinated process. But even a small “breakdown” in the processes of formation and circulation of cerebrospinal fluid should happen - this will definitely affect the condition of a child or an adult.

Particularly important in this regard is the 3rd ventricle of the brain, the norm of which is indicated below:

Newborns -3-5 mm.
Children 1-3 months -3-5 mm.
Children 3 months - 6 years -3-6 mm.
Adults -4-6 mm.

Common diseases of the third ventricle of the brain

Most often, the problem of violation of the outflow of cerebrospinal fluid occurs in children - newborns and babies up to a year. One of the most common diseases at this age is ICH () and its complication is hydrocephalus.

During pregnancy, the expectant mother undergoes obligatory ultrasound of the fetus, which makes it possible to identify congenital malformations of the central nervous system of the child in the early stages. If during the examination the doctor notes that the 3rd ventricle of the brain is enlarged, additional diagnostic tests and careful medical supervision will be required.

If the cavity of the 3rd ventricle in the fetus expands more and more, in the future such a baby may need a bypass operation to restore the normal outflow of cerebrospinal fluid.

Also, all born babies at the age of two months (according to indications - earlier) undergo a mandatory medical examination by a neurologist, who may suspect an expansion of the 3rd ventricle and the presence of ICH. Such children are sent for a special examination of brain structures - (neurosonography).

What is NSG?

Neurosonography is a special type of ultrasound examination of the brain. It can be carried out in infants, because they have a small physiological opening in the skull - a fontanelle.

Using a special sensor, the doctor receives an image of all the internal structures of the brain, determines their size and location. If the 3rd ventricle is enlarged by NSG, more detailed tests are performed - computed tomography (CT) or magnetic resonance imaging (MRI) to obtain a more accurate picture of the disease and confirm the diagnosis.

Which doctors should be contacted when making a diagnosis of ICH?

If the 3rd ventricle of the baby's brain is slightly enlarged and the mother has no serious complaints, regular monitoring by the district pediatrician is sufficient. Consultation of a neuropathologist and a neurosurgeon is necessary if there is a significant expansion of the ventricles on ultrasound or symptoms of ICH:

the child began to suck worse at the breast;
the fontanel is tense, protrudes above the surface of the skull;
saphenous veins of the scalp are dilated;
Graefe's symptom - a section of white sclera between the iris and eyelid when looking down;
loud, sharp cry;
vomit;
divergence of the sutures of the skull;
rapid increase in head size.

Doctors determine the further tactics of treating a baby with: conservative means the appointment of vascular drugs, massage, physiotherapy; surgical - performing an operation. After therapy, children quickly recover, the activity of the nervous system is restored.

Colloidal cyst of the 3rd ventricle is a disease common among adults 20-40 years old. It is characterized by the appearance of a benign rounded formation in the cavity of the 3rd ventricle, not prone to rapid growth and metastasis.

By itself, a colloid cyst does not pose any danger to human health. Problems begin if it reaches a large size and prevents the outflow of cerebrospinal fluid. In this case, the patient has neurological symptoms associated with an increase in intracranial pressure:

severe headache;
vomit;
visual impairment;
convulsions.

A neuropathologist and a neurosurgeon are jointly engaged in the diagnosis and treatment of a colloid cyst of the third ventricle. With a pronounced size of the formation, determined by CT or, surgical treatment of the cyst is prescribed. After the operation, the normal flow of cerebrospinal fluid is quickly restored, and all symptoms of the disease disappear.

Summing up

Thus, the third ventricle is an important element of the CSF system, the diseases of which can lead to serious consequences. Attentive attitude to health and timely access to doctors will help to quickly and permanently cope with the disease.

VENTRICLES OF THE BRAIN (ventriculi cerebri) - cavities located in the brain, lined with ependyma and filled with cerebrospinal fluid. Functional value Zh. of the m is defined by the fact that they are the place of formation and the receptacle of cerebrospinal liquid (see), and also a part of liquor-conducting ways.

Available four ventricles: lateral ventricles(ventriculi lat., first and second), third ventricle(ventriculus tertius) and fourth ventricle(ventriculus quartus). First described by Herophilus in the 4th c. BC e. Of great importance in the study of CSF pathways were the discoveries of the cerebral aqueduct by F. Sylvius, the interventricular orifice of A. Monroe, the median orifice of the fourth ventricle of F. Magendie, the lateral orifices of the fourth ventricle of G. Lushka, and also the introduction to honey. practice of the method of ventriculography W. Dandy (1918).

The translational movement of the cerebrospinal fluid is directed from the GC through the unpaired median foramen of the fourth ventricle (Magendie) and the paired lateral foramina of the fourth ventricle (Lushka) into the cerebellar-cerebral cistern, from there the cerebrospinal fluid spreads through the cisterns of the base of the brain, channels along the convolutions of the brain on its convex surface and into the subarachnoid space of the spinal cord and its central canal. The capacity of all ventricles is 30-50 ml.

Embryology

Zh. m., as well as the cavities of the spinal cord [central canal (canalis centralis) and terminal ventricle (ventriculus terminalis)], are formed as a result of transformations of the primary cavity of the neural tube - the nerve canal. The nerve canal gradually narrows throughout the spinal cord and turns into the central canal and the terminal ventricle. The anterior end of the neural tube expands and then dissects, forming on the 4th week. development of three brain bubbles (Fig. 1): anterior, middle and rhomboid. On the 5-6th week. development by differentiation of the three brain bubbles, five bubbles are formed, giving rise to five main parts of the brain: the end brain (telencephalon), diencephalon (diencephalon), midbrain (mesencephalon), hindbrain (metencephalon), medulla oblongata (myelencephalon).

The telencephalon grows intensively to the sides, forming two lateral bubbles - the rudiments of the cerebral hemispheres. The primary cavity of the telencephalon (telocele) gives rise to the cavities of the lateral blisters, which are the anlage of the lateral ventricles. On the 6-7th week. development, the growth of lateral bubbles occurs in the lateral and anterior directions, which leads to the formation of the anterior horn of the lateral ventricles; on the 8-10th week. there is a growth of lateral vesicles in the opposite direction, as a result of which the posterior and inferior horns of the ventricles appear. Due to the increased growth of the temporal lobes of the brain, the lower horns of the ventricles move laterally, down and forward. Part of the cavity of the telencephalon, which is in connection with the cavities of the lateral vesicles, turns into interventricular holes (foramina interventricularia), which communicate the lateral ventricles with the anterior part of the third ventricle. The primary cavity of the diencephalon (diocele) narrows, keeping in touch with the middle part of the cavity of the telencephalon, and gives rise to the third ventricle. The cavity of the midbrain (mesocele), which passes from the front into the third ventricle, narrows very strongly even on the 7th week. turns into a narrow canal - the aqueduct of the brain (aqueductus cerebri), connecting the third ventricle with the fourth. At the same time, the cavity of the rhomboid brain, which gives rise to the hindbrain and medulla oblongata, expanding laterally, forms the fourth ventricle with its side pockets (recessus lat.). The vascular base of the fourth ventricle (tela chorioidea ventriculi quarti) at first almost completely closes its cavity (with the exception of the opening of the cerebral aqueduct). By the 10th week development in it and in the wall of the ventricle, openings are formed: one median (apertura mediana) at the lower corner of the rhomboid fossa and two paired lateral (aperturae lat.) at the tops of the lateral pockets. Through these openings, the fourth ventricle communicates with the subarachnoid space of the brain. The cavity of the fourth ventricle passes below into the central canal of the spinal cord.

Anatomy

Lateral ventricles are located in the cerebral hemispheres (Fig. 2-4 and color. Fig. 11). They consist of a central part (pars centralis), which lies in the parietal lobe, and three processes extending from it on each side - horns. The anterior horn (cornu ant.) is located in the frontal lobe, the posterior horn (cornu post.) is in the occipital lobe, the lower horn (cornu inf.) is in the temporal lobe. The anterior horn has a triangular shape, bounded from the inside by a transparent septum (septum pellucidum), outside and behind - by the head of the caudate nucleus (caput nuclei caudati), above and in front - by the corpus callosum (corpus callosum). Between the two plates of the transparent septum is its cavity (cavum septi pellucidi). The central part of a ventricle has the form of a crack, the bottom a cut is formed by a caudate kernel, external department of an upper surface of a thalamus and the final strip lying between them (stria terminalis). Inside, it is closed by an epithelial plate, covered from above by the corpus callosum. The posterior horn extends posteriorly from the central part of the lateral ventricle and down the lower horn. The place of transition of the central part into the posterior and lower horns is called the collateral triangle (trigonum collaterale). The posterior horn, lying among the white matter of the occipital lobe of the brain, has a triangular shape, it gradually narrows posteriorly; on its inner surface there are two longitudinal protrusions: the lower one is the bird's spur (calcar avis), corresponding to the spur groove, and the upper one is the bulb of the posterior horn (bulbus cornus post.), formed by the fibers of the corpus callosum. The lower horn goes down and forward and ends at a distance of 10-14 mm from the temporal pole of the hemispheres. Its upper wall is formed by the tail of the caudate nucleus and the terminal strip. On the medial wall there is an elevation - the hippocampus (hippocampus), a cut is created due to the depression of the parahippocampal groove (gyrus parahippocampalis) lying deep from the surface of the hemisphere. The lower wall, or the bottom of the horn, is limited by the white matter of the temporal lobe and bears a roller - a collateral elevation (eminentia collateralis), corresponding to the outside of the collateral groove. From the medial side, the pia mater protrudes into the lower horn, forming the choroid plexus of the lateral ventricle (plexus chorioideus ventriculi lat.). The lateral ventricles are closed on all sides, with the exception of the interventricular (Monroy) foramen, through which the lateral ventricles are connected to the third ventricle and through it to each other.

Third ventricle - an unpaired cavity having a slit-like shape. It is located in the diencephalon in the middle between the medial surfaces of the thalamus and the hypothalamus. In front of the third ventricle are the anterior commissure (commissura ant.), column of the arch (columna fornicis), end plate (lamina terminalis); behind - posterior commissure (commissura post.), commissure of leashes (commissura habenularum); below - posterior perforated substance (substantia perforata post.), gray tubercle (tuber cinereum), mastoid bodies (corpora mamillaria) and optic chiasm (chiasma opticum); above - the vascular base of the third ventricle, attached to the upper surface of the thalamus, and above it - the legs of the arch (crura fornicis), connected by the commissure of the arch, and the corpus callosum. Laterally from the midline, the vascular base of the third ventricle contains the choroid plexus of the third ventricle (plexus chorioideus ventriculi tertii). In the middle of the third ventricle, the right and left thalamus are connected by an interthalamic fusion (adhesio interthalamica). The third ventricle forms deepenings: deepening of the funnel (recessus infundibuli), visual deepening (recessus opticus), epiphyseal deepening (recessus pinealis). Through the aqueduct of the brain, the third ventricle is connected to the fourth.

fourth ventricle. The bottom of the fourth ventricle, or rhomboid fossa (fossa rhomboidea), is formed by the bridge of the brain (see) and the medulla oblongata (see), on the border of which the fourth ventricle forms lateral recesses (recessus lat. ventriculi quarti). The roof of the fourth ventricle (tegmen ventriculi quarti) has the shape of a tent and is composed of two cerebral sails - an unpaired upper one (velum medullare sup.), stretching between the upper legs of the cerebellum, and a paired lower one (velum medullare inf.), fixed to the legs of the shred (pedunculus flocculi) . Between the sails, the roof of the ventricle is formed by the cerebellum. The lower medullary sail is covered with a vascular basis of the fourth ventricle (tela chorioidea ventriculi quarti), the choroid texture of a ventricle is connected with a cut. The cavity of the fourth ventricle communicates with the subarachnoid space with three openings: unpaired median, located no midline in the lower parts of the fourth ventricle, and paired lateral - in the region of the lateral depressions of the fourth ventricle. In the lower sections, the fourth ventricle, gradually narrowing, passes into the central canal of the spinal cord, which expands below into the terminal ventricle.

Pathology

Inflammatory processes in Zh. m. (ventriculitis) can be observed at various infectious defeats and intoxications of c. n. With. (eg, with meningoencephalitis, etc.). In acute ventriculitis, a picture of serous or purulent ependymatitis may develop (see Chorioependymatitis). At hron, productive periventricular encephalitis there is a sealing of the ependyma of the ventricles, sometimes taking a granular appearance, which is caused by warty reactive growths of the subependymal layer. The course of ependymatitis is often aggravated due to impaired circulation of cerebrospinal fluid due to obstruction of its outflow tracts at the level of the interventricular orifices, the cerebral aqueduct, and the unpaired median orifice of the fourth ventricle.

Clinically, violations of the circulation of cerebrospinal fluid in ventriculitis are manifested by paroxysms of headaches, during which patients, depending on the level of difficulty in the outflow of cerebrospinal fluid, take characteristic forced positions with the head tilted forward, tilting it back, etc. (see Occlusion syndrome). Nevrol, the symptomatology at ventriculitis is polymorphic; it is manifested by a wide range of symptoms from the periventricular (periventricular) structures of the diencephalic parts of the brain (arterial hypertension, hyperthermia, diabetes insipidus, narcolepsy, cataplexy), midbrain (oculomotor disorders), hindbrain and medulla oblongata - the bottom of the fourth ventricle (vestibular disorders, symptoms of lesions nuclei VI, VII cranial nerves, etc.). In acute ventriculitis, ventricular cerebrospinal fluid usually shows cytosis; in chronic ventriculitis, the ventricular fluid may be hydrocephalic (decrease in protein content with a normal number of cells).

Primary hemorrhages in Zh. m. meet seldom and in overwhelming majority of cases happen traumatic genesis. Secondary hemorrhages are more often observed, which are the result of a breakthrough of intracerebral hematomas (traumatic, after a stroke) into the cavity of the ventricles. These hemorrhages are manifested by the acute development of a coma with pronounced reactions from the cardiovascular system, respiratory disorders, hyperthermia, dissociated meningeal symptoms, often hormetonic syndrome (see Hormetonia). An admixture of blood is found in the cerebrospinal fluid.

brain, tumors). Tumors of the lateral ventricles are clinically manifested by a relapsing course with occlusive-hydrocephalic paroxysms due to obstruction of the interventricular openings. During paroxysms, there is a forced position of the head and symptoms of infringement of the brain stem sections (gaze paralysis upwards, bilateral pathological reflexes on the legs, disorders of cardiovascular activity and respiration). Dissociated meningeal symptoms are often observed as a manifestation of tonic reflexes due to irritation of the brain stem structures. In addition, periventricular symptoms can be detected as a result of the impact of the tumor on the adjacent parts of the brain (motor and sensory disorders that change in severity over time, hemianopsia, unilateral symptoms of subcortical lesions, general epileptic seizures with a tonic convulsive component, etc.). In the ventricular cerebrospinal fluid, there is usually a sharp increase in protein, often combined with an increase in the number of cells and xanthochromia.

Tumors of the third ventricle are characterized by a combination of hypertensive-hydrocephalic symptoms due to occlusion of the circulation pathways of the cerebrospinal fluid - the aqueduct of the brain and interventricular (Monroy) openings with various metabolic-endocrine and vegetative-vascular disorders, which often serve as the first manifestations of the disease. There are seizures of the cataplectoid type, sleep rhythm disturbances, sometimes patol, drowsiness. In the later stages of the disease - attacks of decerebrate rigidity with respiratory and cardiovascular disorders. In the cerebrospinal fluid, there is usually a significant increase in protein, sometimes with an increase in the number of cells and xanthochromia.

The wedge, the picture of a tumor of the fourth ventricle consists of symptoms of damage to nuclear formations of the periventricular structures of its bottom and hypertensive-hydrocephalic symptoms due to obstruction of the outflow tracts of cerebrospinal fluid. Characterized by paroxysms of headaches with vomiting, dizziness and impaired cardiovascular activity and respiration (Bruns attacks). A constant symptom is pronounced stem nystagmus.

When diagnosing pathology Zh. m., in addition to analyzing the features of the wedge, manifestations, they use ventriculography (see), ventriculoscopy (see) and encephalography (see) using water-soluble emulsion and gas radiopaque substances and radioisotopes (Fig. 8- 10).

Treatment

In inflammatory processes, surgical intervention is resorted to in cases of development of occlusive phenomena (see Hydrocephalus). As a temporary measure for acute occlusion of the CSF outflow pathways, ventriculopuncture is used to reduce intraventricular pressure (see).

In cases where occlusion cannot be surgically eliminated, palliative operations are performed to create a roundabout way for the outflow of cerebrospinal fluid from the ventricles (ventriculostomy operations, perforation of the end plate, ventriculosubdural anastomosis, ventriculocisternostomy).

Of the conservative methods of treating ventriculitis, dehydration is used to reduce intracranial pressure and reduce the hypertensive syndrome (see Dehydration Therapy). In acute and chronic infectious ventriculitis, anti-inflammatory treatment is carried out.

Bibliography: Multi-volume guide to neurology, ed. S. N. Davidenkova, vol. 5, M., 1961; Multivolume guide to surgery, ed. B. V. Petrovsky, vol. 3, book. 2, M., 1968; Patten B. M. Human embryology, trans. from English, M., 1959; Shelia R. N. Tumors of the ventricular system of the brain, L., 1973; G 1 and M. Das Nerven-system des Menschen, Lpz., 1953; G o r-rales M. a. T o r r e a 1 b a G. The third ventricle, Normal anatomy and changes in some pathological conditions, Neuroradiology, v. 11, p. 271, 1976, bibliogr.; Messert B., Wanna-maker B. B. a. Dudley A. W. Reevaluation of the size of the laterol ventricles of the brain, Postmortem study of an adult population, Neurology (Min-neap.), v. 22, p. 941, 1972.

E. P. Kononova, S. S. Mikhailov; H. Ya. Vasin (neurochir.).

Third ventricle, ventriculus tertius. The cavity of the diencephalon. It is located between the terminal plate and the beginning of the aqueduct of the brain. Rice. A, V.
Hypothalamic groove, sulcus hypothalamicus. Passes from the interventricular opening to the entrance to the cerebral aqueduct. Separates the posterior thalamus from the anterior thalamus. Rice. A.
Interventricular foramen, foramen interventriculare. Communication between the lateral and III ventricles behind the column of the fornix. Rice. A.
Visual deepening, recessus opticus. Protrusion of the lower wall of the third ventricle above the optic chiasm. Rice. A.
Deepening of the funnel, recessus infundibuli (infundibularis). A niche in the lower wall of the third ventricle leading to the infundibulum. Rice. A.
Pineal recess, recessus pinealis. Blind pocket of the third ventricle that extends into the pineal gland. Rice. A.
Suprapineal depression, recessus suprapinealis. It is located between the roof of the third ventricle and the pineal body. Rice. A.
Vascular basis of the third ventricle, tela choroidea ventriculi tertii. Forms the upper wall of the third ventricle and contains the choroid plexus. Rice. B, V.
Thalamic ribbon, taenia thalami. Runs parallel to the thalamus. The site of attachment of the upper wall of the third ventricle. Rice. B, V.
Vascular plexus of the third ventricle, plexus choroideus ventriculi tertii. A paired, with a large number of vessels, villous formation, which protrudes into the cavity of the III ventricle from the side of its upper wall. Through the interventricular opening it continues into the choroid plexus of the lateral ventricle. Rice. B, V.
Sections of the thalamus, sectiones thalamici et metathala.
Reticular nucleus [thalamus], nucleus reticulatus. A thin layer of gray matter between the posterior crus of the internal capsule and the outer medullary plate. Fibers from various parts of the cerebral cortex, the globus pallidus and the reticular formation of the brain stem approach it. Fibers from the nucleus reticulatus go to the neighboring nuclei of the thalamus and to the reticular formation of the midbrain. Rice. B.
Anterior nuclei [thalamus], nuclei anteriores. Located in the region of the anterior tubercle of the thalamus. The fibers of the mastoid-thalamic bundle approach them. The processes of the neurons of the anterior nuclei of the thalamus are sent to the cingulate gyrus.
Anterior dorsal nucleus, nucleus anterodorsalis (anterosuperior). A narrow cell plate located above and in front of the rest of the anterior nuclei (thalamus). Rice. B.
Anteroventral nucleus, nucleus anteroventralis (anteroinferior). The main nucleus is part of the anterior nuclei (thalamus). Rice. B.
Anterior medial nucleus, nucleus anteromedialis. A rudimentary nucleus located medially and inferior to the anteroventral nucleus. Rice. B.
Median nuclei [thalamus], nuclei mediani. Localized under the ependyma covering the medial surface of the thalamus. Consists of the following three groups.
Anterior / posterior paraventricular nuclei, nuclei paraventriculares anteriores / posteriores. Located in the wall of the third ventricle. They consist of cells with neurosecretory activity (vasopressin, angiotensin II, renin are secreted). Rice. B, G, D.
Rhomboid nucleus, nucleus rhomboidalis. Located in the metathalamic fusion. Rice. G.
Connecting core, nucleus reuniens. It starts from the anterior tubercle of the thalamus and enters the interthalamic fusion. Absent in 28% of men and 14% of women. Rice. G.
20a. Paratenial nucleus [thalamus], nucleus parataenialis. It is located between the brain strip, the thalamic ribbon, the anterior dorsal and paraventricular nuclei of the thalamus. Probably related to the olfactory pathway.
Medial nuclei [thalamus], nuclei medialis. Located medial to the internal cerebral plate. Associated with other nuclei of the thalamus and the cortex of the frontal lobe.
Dorsal medial nucleus, nucleus medialis dorsalis. The main nucleus is part of the medial nuclei (thalamus). Rice. V, G.
Brain plates, internal/external, laminae medullaris interna/externa. The inner plate is a layer of white matter, which splits into two sheets in the anterior superior part of the thalamus, dividing it into anterior, medial and lateral parts. The outer plate faces the inner capsule. Rice. B.
Reticular (intralamellar) nuclei [thalamus], nuclei reticulares (intralaminares thalami). Located in the brain plate. They are integrative nuclei and functionally correspond to the reticular formation.
Central median nucleus, nucleus centromedianus. The largest of the intralamellar nuclei. Associated with the striatum and hypothalamus. Rice. D.
Paracentral nucleus, nucleus paracentralis. It is determined as part of the internal cerebral plate outside the central median nucleus. Rice. V, G.
Parafascicular nucleus, nucleus parafascicularis. Lies medial to the posterior part of the central median nucleus. Rice. D.
Lateral central nucleus, nucleus centralis lateralis. Lies dorsomedial to the central median nucleus. Rice. V, D.
Medial central nucleus, nucleus centralis medialis. It is located at the lower edge of the inner cerebral plate.

The ventricles of the brain are considered an anatomically important structure. They are presented in the form of peculiar voids lined with ependyma and communicating with each other. In the process of development, the brain vesicles form from the neural tube, which subsequently transform into the ventricular system.

Tasks

The main function of the ventricles of the brain is the production and circulation of CSF. It protects the main parts of the nervous system from a variety of mechanical damage, maintaining a normal level. The cerebrospinal fluid takes part in the delivery of nutrients to neurons from the circulating blood.

Structure

All ventricles of the brain have special vascular plexuses. They produce liquor. The ventricles of the brain are interconnected by the subarachnoid space. Thanks to this, the movement of liquor is carried out. First, from the lateral ones, it penetrates into the 3rd ventricle of the brain, and then into the fourth. At the final stage of circulation, the outflow of CSF into the venous sinuses occurs through granulations in the arachnoid membrane. All parts of the ventricular system communicate with each other through channels and openings.

Kinds

The lateral parts of the system are located in the cerebral hemispheres. Each lateral ventricle of the brain communicates with the cavity of the third through a special foramen of Monroe. In the center is the third section. Its walls form the hypothalamus and thalamus. The third and fourth ventricles are connected to each other through a long canal. It is called the Sylvius Passage. It circulates cerebrospinal fluid between the spinal cord and the brain.

Lateral departments

Conventionally, they are called the first and second. Each lateral ventricle of the brain includes three horns and a central region. The latter is located in the parietal lobe. The anterior horn is located in the frontal, the lower - in the temporal, and the posterior - in the occipital zone. In their perimeter there is a vascular plexus, which is dispersed rather unevenly. So, for example, it is absent in the posterior and anterior horns. The choroid plexus begins directly in the central zone, descending gradually into the lower horn. It is in this region that the size of the plexus reaches its maximum value. For this, this area is called a tangle. The asymmetry of the lateral ventricles of the brain is caused by a violation in the stroma of the tangles. Also often this area undergoes degenerative changes. Such pathologies are quite easily detected on conventional radiographs and carry a special diagnostic value.

The third cavity of the system

This ventricle is located in the diencephalon. It connects the lateral divisions with the fourth. As in other ventricles, the choroid plexuses are present in the third. They are distributed along its roof. The ventricle is filled with cerebrospinal fluid. In this department, the hypothalamic groove is of particular importance. Anatomically, it is the border between the thalamus and hypothalamus. The third and fourth ventricles of the brain are connected by the aqueduct of Sylvius. This element is considered one of the important components of the midbrain.

fourth cavity

This department is located between the bridge, the cerebellum and the medulla oblongata. The shape of the cavity is similar to a pyramid. The floor of the ventricle is called the rhomboid fossa. This is due to the fact that anatomically it is a depression that looks like a rhombus. It is lined with gray matter with a large number of tubercles and depressions. The roof of the cavity is formed by the lower and upper medullary sails. She seems to be hanging over the hole. The choroid plexus is relatively autonomous. It includes two lateral and medial sections. The choroid plexus is attached to the lateral lower surfaces of the cavity, spreading to its lateral inversions. The ventricular system communicates with the subarachnoid and subarachnoid spaces through the medial foramen of Magendie and the symmetrical lateral foramina of Luschka.

Structure changes

The expansion of the ventricles of the brain negatively affects the activity of the nervous system. Their condition can be assessed using diagnostic methods. So, for example, in the process of computed tomography, it is revealed whether the ventricles of the brain are enlarged or not. MRI is also used for diagnostic purposes. Asymmetry of the lateral ventricles of the brain or other disorders can be triggered by various reasons. Among the most popular provoking factors, experts call the increased formation of cerebrospinal fluid. This phenomenon accompanies inflammation in the choroid plexus or papilloma. Asymmetry of the ventricles of the brain or a change in the size of the cavities may be the result of a violation of the outflow of CSF. This happens when the openings of Luschka and Magendie become impassable due to the appearance of inflammation in the membranes - meningitis. The cause of obstruction may also be metabolic reactions against the background of vein thrombosis or subarachnoid hemorrhage. Often, asymmetry of the ventricles of the brain is detected in the presence of volumetric neoplasms in the cranial cavity. It can be an abscess, hematoma, cyst or tumor.

The general mechanism for the development of disorders of the cavities

At the first stage, there is difficulty in the outflow of cerebral fluid into the subarachnoid space from the ventricles. This provokes the expansion of the cavities. At the same time, there is compression of the surrounding tissue. In connection with the primary blockade of the outflow of fluid, a number of complications arise. One of the main is the occurrence of hydrocephalus. Patients complain of headaches that occur suddenly, nausea, and in some cases vomiting. Violations of vegetative functions are also found. These symptoms are caused by an increase in pressure inside the ventricles of an acute nature, which is characteristic of some pathologies of the cerebrospinal fluid system.

cerebral fluid

The spinal cord, like the brain, is located inside the bone elements in a suspended state. Both are washed by liquor from all sides. Cerebrospinal fluid is produced in the choroid plexuses of all ventricles. CSF circulation is carried out due to the connections between the cavities in the subarachnoid space. In children, it also passes through the central spinal canal (in adults, it overgrows in some areas).