Terminal brain. Furrows and convolutions Furrows and convolutions of the brain their meaning

Logistics of the lesson

1. Corpse, skull.

2. Tables and dummies on the topic of the lesson

3. A set of general surgical instruments

Technological map of the practical lesson.

Clinical situation

A victim in a car accident has a fracture of the base of the skull, accompanied by bleeding from the ears and symptoms of "glasses".

Tasks:

1. Explain at what level did the skull base fracture occur?

2. What is the basis of the phenomena that have arisen?

3. Prognostic value of liquorrhea.

The solution of the problem:

1. Fracture of the base of the skull is localized in the region of the middle cranial fossa.

2. Bleeding from the ears is caused by damage to the pyramid of the temporal bone, the tympanic membrane and the middle cerebral artery. The symptom of "points" is due to the spread of a hematoma through the superior orbital fissure into the fiber of the orbit.

3. Liquorrhea - a prognostically unfavorable symptom, indicates damage to the arachnoid and dura mater.

brain covered three shells(Fig. 1), of which the outermost is the dura mater encephali. It consists of two sheets, between which a thin layer of loose fiber is laid. Due to this, one sheet of the membrane can be easily separated from another and used to replace a defect in the dura mater (the Burdenko method).

On the vault of the skull, the dura mater is loosely connected with the bones and easily flakes off. The inner surface of the bones of the cranial vault itself is lined with a connective tissue film, which contains a layer of cells resembling an endothelium; between it and a similar layer of cells covering the outer surface of the dura mater, a slit-like epidural space is formed. At the base of the skull, the dura mater is very firmly connected to the bones, especially on the perforated plate of the ethmoid bone, in the circumference of the Turkish saddle, on the clivus, in the region of the pyramids of the temporal bones.

According to the midline of the cranial vault, or somewhat to the right of it, there is an upper falx-shaped process of the dura mater (falx cerebri), which separates one cerebral hemisphere from the other (Fig. 2). It stretches in the sagittal direction from the crista galli to the protuberantia occipitalis interna.

The lower free edge of the crescent crescent almost reaches the corpus callosum (corpus callosum). In the posterior part, the crescent crescent connects to another process of the dura mater - the roof, or tent, of the cerebellum (tentorium cerebelli), which separates the cerebellum from the cerebral hemispheres. This process of the dura mater is located almost horizontally, forming some kind of arch, and is attached behind - on the occipital bone (along its transverse grooves), from the sides - on the upper edge of the pyramid of both temporal bones, in front - on the processus clinoidei of the sphenoid bone.

Rice. 1. Shells of the brain, meninges encephali; front view:

1 - superior sagittal sinus, sinus sagittalis superior;

2 - scalp;

3 - hard shell of the brain, dura mater cranialis (encephali);

4 - arachnoid membrane of the brain, arachnoidea mater cranialis (encephali);

5 - soft shell of the brain, pia mater cranialis (encephali);

6 - cerebral hemispheres, hemispherium cerebralis;

7 - crescent of the brain, falx cerebri;

8 - arachnoid membrane of the brain, arachnoidea mater cranialis (encephali);

9 - skull bone (diploe);

10 - pericranium (periosteum of the bones of the skull), pericranium;

11 - tendon helmet, galea aponeurotica;

12 - granulation of the arachnoid, granulationes arachnoidales.

For most of the length of the posterior cranial fossa, the cerebellar tent separates the contents of the fossa from the rest of the cranial cavity, and only in the anterior section of the tentorium there is an oval-shaped opening - incisura tentorii (otherwise - the pachyon opening), through which the brain stem passes. With its upper surface, tentorium cerebelli connects along the midline with falx cerebelli, and from the lower surface of the tent of the cerebellum, also along the midline, falx cerebelli, which is insignificant in height, penetrates into the groove between the hemispheres of the cerebellum.

Rice. 2. Processes of the dura mater; The cranial cavity was opened on the left:

2 - notch of the cerebellum tentorium, incisura tentorii;

3 - cerebellum tentorium, tentorium cerebelli;

4 - sickle of the cerebellum, falx cerebelli;

5 - trigeminal cavity, cavitas trigeminalis;

6 - diaphragm of the saddle, diaphragma sellae;

7 - tentorium of the cerebellum, tentorium cerebelli.

In the thickness of the processes of the dura mater there are valveless venous sinuses (Fig. 3). The crescent process of the dura mater throughout its entire length contains the superior sagittal venous sinus (sinus sagittalis superior), which is adjacent to the bones of the cranial vault and is often damaged in injuries and gives very strong, difficult to stop bleeding. The external projection of the superior sagittal sinus corresponds to the sagittal line connecting the base of the nose with the external occipital protuberance.

The lower free edge of the cerebral sickle contains the lower sagittal sinus (sinus sagittalis inferior). Along the line of connection of the crescent crescent and the tent of the cerebellum is a straight sinus (sinus rectus), into which the lower sagittal sinus flows, as well as a large vein of the brain (Galena).

Rice. 3. Sinuses of the dura mater; general form; The cranial cavity was opened on the left:

1 - crescent of the brain, falx cerebri;

2 - lower sagittal sinus, sinus sagittalis inferior;

3 - lower stony sinus, sinus petrosus inferior;

4 - superior sagittal sinus, sinus sagittalis superior;

5 - sigmoid sinus, sinus sigmoideus;

6 - transverse sinus, sinus transversus;

7 - large cerebral (Galena) vein, v.cerebri magna (Galeni);

8 - straight sinus, sinus rectus;

9 - tent (tent) of the cerebellum, tentorium cerebelli;

11 - marginal sinus, sinus marginalis;

12 - superior stony sinus, sinus petrosus superior;

13 - cavernous sinus, sinus cavernosus;

14 - stony-parietal sinus, sinus sphenoparietalis;

15 - superior cerebral veins, vv.cerebrales superiores.

In the thickness of the sickle of the cerebellum, along the line of attachment to the internal occipital crest, contains the occipital sinus (sinus occipitalis).

A number of venous sinuses are located at the base of the skull (Fig. 4). In the middle cranial fossa there is a cavernous sinus (sinus cavernosus). This paired sinus, located on both sides of the Turkish saddle, the right and left sinuses are connected by anastomoses (intercavernous sinuses, sinusi intercavernosi), forming Ridley's annular sinus - sinus circularis (Ridleyi) (BNA). The cavernous sinus collects blood from the small sinuses of the anterior part of the cranial cavity; in addition, what is especially important, the ophthalmic veins (vv.ophthalmicae) flow into it, of which the upper one anastomoses with v.angularis at the inner corner of the eye. Through the emissaries, the cavernous sinus is directly connected with the deep venous plexus on the face - plexus pterygoideus.

Rice. 4. Venous sinuses of the base of the skull; view from above:

1 - basilar plexus, plexus basilaris;

2 - superior sagittal sinus, sinus sagittalis superior;

3 - wedge-parietal sinus, sinus sphenoparietalis;

4 - cavernous sinus, sinus cavernosus;

5 - lower stony sinus, sinus petrosus inferior;

6 - upper stony sinus, sinus petrosus superior;

7 - sigmoid sinus, sinus sigmoideus;

8 - transverse sinus, sinus transversus;

9 - sinus drain, confluens sinuum;

10 - occipital sinus, sinus occipitalis;

11 - marginal sinus, sinus marginalis.

Inside the cavernous sinus are a. carotis interna and n.abducens, and in the thickness of the dura mater, which forms the outer wall of the sinus, the nerves pass (counting from top to bottom) - nn.oculomotorius, trochlearis and ophthalmicus. To the outer wall of the sinus, in its posterior section, the semilunar ganglion of the trigeminal nerve adjoins).

The transverse sinus (sinus transversus) is located along the groove of the same name (along the line of attachment of the tentorium cerebelli) and continues into the sigmoid (or S-shaped) sinus (sinus sigmoideus), located on the inner surface of the mastoid part of the temporal bone to the jugular foramen, where it passes into the superior bulb internal jugular vein. The projection of the transverse sinus corresponds to a line that forms a slight bulge upward and connects the external occipital protuberance with the upper posterior part of the mastoid process. This projection line roughly corresponds to the upper protruding line.

The superior sagittal, rectus, occipital and both transverse sinuses merge in the region of the internal occipital protuberance, this fusion is called the confluens sinuum. The external projection of the confluence is the occipital protuberance. The sagittal sinus does not merge with other sinuses, but passes directly into the right transverse sinus.

The arachnoid membrane (arachnoidea encephali) is separated from the hard shell by a slit-like, so-called subdural space. It is thin, does not contain blood vessels and, unlike the pia mater, does not enter the furrows that delimit the cerebral gyrus.

The arachnoid membrane forms special villi that perforate the dura mater and penetrate the lumen of the venous sinuses or leave imprints on the bones - they are called arachnoid granulations (in other words, pachyon granulations).

Closest to the brain is the pia mater encephali, which is rich in blood vessels; it enters all the furrows and penetrates into the cerebral ventricles where its folds with numerous vessels form the choroid plexuses.

Between the pia mater and the arachnoid there is a slit-like subarachnoid (subarachnoid) space of the brain, which directly passes into the same space of the spinal cord and contains cerebrospinal fluid. The latter also fills the four ventricles of the brain, of which IV communicates with the subarachnoid space of the brain through the lateral openings of the foramen Luchca, and through the medial opening (foramen Magandi) communicates with the central canal and the subarachnoid space of the spinal cord. The IV ventricle communicates with the III ventricle via the Sylvian aqueduct.

In the ventricles of the brain, in addition to cerebrospinal fluid, there are choroid plexuses.

The lateral ventricle of the brain has a central section (located in the parietal lobe) and three horns: anterior (in the frontal lobe), posterior (in the occipital lobe) and lower (in the temporal lobe). Through two interventricular openings, the anterior horns of both lateral ventricles communicate with the third ventricle.

Several expanded sections of the subarachnoid space are called cisterns. They are located mainly at the base of the brain, with the cisterna cerebellomedullaris having the greatest practical value, delimited from above by the cerebellum, in front by the medulla oblongata, from below and behind by that part of the meninges that adjoins the membrana atlantooccipitalis. The cistern communicates with the IV ventricle through its middle opening (foramen Magandi), and below it passes into the subarachnoid space of the spinal cord. The puncture of this cistern (suboccipital puncture), which is often also called the cisternum major or posterior cistern, is used to administer drugs, lower intracranial pressure (in some cases), and for diagnostic purposes.

Major sulci and convolutions of the brain

The central sulcus, sulcus centralis (Rolando), separates the frontal lobe from the parietal. Anterior to it is the precentral gyrus - gyrus precentralis (gyrus centralis anterior - BNA).

Behind the central sulcus lies the posterior central gyrus - gyrus postcentralis (gyrus centralis posterior - BNA).

The lateral groove (or fissure) of the brain, sulcus (fissura - BNA) lateralis cerebri (Sylvii), separates the frontal and parietal lobes from the temporal. If the edges of the lateral fissure are parted, a fossa (fossa lateralis cerebri) is revealed, at the bottom of which there is an island (insula).

The parietal-occipital sulcus (sulcus parietooccipitalis) separates the parietal lobe from the occipital lobe.

The projections of the furrows of the brain on the integument of the skull are determined according to the scheme of craniocerebral topography.

The core of the motor analyzer is concentrated in the precentral gyrus, and the most highly located sections of the anterior central gyrus are related to the muscles of the lower limb, and the lowest ones are related to the muscles of the oral cavity, pharynx and larynx. The right-sided gyrus is connected with the motor apparatus of the left half of the body, the left-sided - with the right half (due to the intersection of the pyramidal pathways in the medulla oblongata or spinal cord).

The nucleus of the skin analyzer is concentrated in the postcentral gyrus. The postcentral gyrus, like the precentral, is connected with the opposite half of the body.

The blood supply to the brain is carried out by the systems of four arteries - internal carotid and vertebral (Fig. 5). Both vertebral arteries at the base of the skull merge to form the main artery (a.basilaris), which runs in a groove on the lower surface of the cerebral bridge. Two aa.cerebri posteriores depart from a.basilaris, and from each a.carotis interna - a.cerebri media, a.cerebri anterior and a.communicans posterior. The latter connects a.carotis interna with a.cerebri posterior. In addition, there is an anastomosis between the anterior arteries (aa.cerebri anteriores) (a.communicans anterior). Thus, the arterial circle of Willis arises - circulus arteriosus cerebri (Willissii), which is located in the subarachnoid space of the base of the brain and extends from the anterior edge of the optic chiasm to the anterior edge of the bridge. At the base of the skull, the arterial circle surrounds the sella turcica and at the base of the brain, the mammillary bodies, the gray tubercle, and the optic chiasm.

The branches that make up the arterial circle form two main vascular systems:

1) arteries of the cerebral cortex;

2) arteries of subcortical nodes.

Of the cerebral arteries, the largest and, in practical terms, the most important is the middle one - a.cerebri media (in other words, the artery of the lateral fissure of the brain). In the region of its branches, more often than in other regions, hemorrhages and embolisms are observed, which was also noted by N.I. Pirogov.

Cerebral veins usually do not accompany arteries. There are two systems: the superficial vein system and the deep vein system. The first are located on the surface of the cerebral convolutions, the second - in the depths of the brain. Both those and others flow into the venous sinuses of the dura mater, and the deep ones, merging, form a large vein of the brain (v.cerebri magna) (Galeni), which flows into the sinus rectus. The great vein of the brain is a short trunk (about 7 mm) located between the thickening of the corpus callosum and the quadrigemina.

In the system of superficial veins, there are two anastomoses that are important in practical terms: one connects the sinus sagittalis superior with the sinus cavernosus (Trolar's vein); the other usually links the sinus transversus to the previous anastomosis (Labbe's vein).

Rice. 5. Arteries of the brain at the base of the skull; view from above:

1 - anterior communicating artery, a.communicans anterior;

2 - anterior cerebral artery, a.cerebri anterior;

3 - ophthalmic artery, a.ophtalmica;

4 - internal carotid artery, a.carotis interna;

5 - middle cerebral artery, a.cerebri media;

6 - superior pituitary artery, a. hypophysialis superior;

7 - posterior communicating artery, a.communicans posterior;

8 - superior cerebellar artery, a.superior cerebelli;

9 - basilar artery, a.basillaris;

10 - canal of the carotid artery, canalis caroticus;

11 - anterior inferior cerebellar artery, a.inferior anterior cerebelli;

12 - posterior inferior cerebellar artery, a.inferior posterior cerebelli;

13 - anterior spinal artery, a. spinalis posterior;

14 - posterior cerebral artery, a.cerebri posterior

Scheme of craniocerebral topography

On the integument of the skull, the position of the middle artery of the dura mater and its branches is determined by the scheme of the craniocerebral (craniocerebral) topography proposed by Krenlein (Fig. 6). The same scheme makes it possible to project the most important furrows of the cerebral hemispheres onto the integument of the skull. The scheme is constructed in the following way.

Rice. 6. Scheme of craniocerebral topography (according to Krenlein-Bryusova).

ac - lower horizontal; df is the middle horizontal; gi is the upper horizontal; ag - front vertical; bh is the middle vertical; cg - back vertical.

From the lower edge of the orbit along the zygomatic arch and the upper edge of the external auditory meatus, a lower horizontal line is drawn. Parallel to it, an upper horizontal line is drawn from the upper edge of the orbit. Three vertical lines are drawn perpendicular to the horizontal lines: the anterior one from the middle of the zygomatic arch, the middle one from the joint of the lower jaw, and the posterior one from the posterior point of the base of the mastoid process. These vertical lines continue to the sagittal line, which is drawn from the base of the nose to the external occiput.

The position of the central sulcus of the brain (Roland's sulcus), between the frontal and parietal lobes, is determined by the line connecting the point of intersection; the posterior vertical with the sagittal line and the point of intersection of the anterior vertical with the upper horizontal; the central sulcus is located between the middle and posterior vertical.

The trunk of a.meningea media is determined at the level of the intersection of the anterior vertical and the lower horizontal, in other words, immediately above the middle of the zygomatic arch. The anterior branch of the artery can be found at the level of the intersection of the anterior vertical with the upper horizontal, and the posterior branch at the level of the intersection of the same; horizontal with vertical back. The position of the anterior branch can be determined differently: lay 4 cm upward from the zygomatic arch and draw a horizontal line at this level; then from the frontal process of the zygomatic bone lay back 2.5 cm and draw a vertical line. The angle formed by these lines corresponds to the position of the anterior branch a. meningea media.

To determine the projection of the lateral fissure of the brain (Sylvian sulcus), which separates the frontal and parietal lobes from the temporal lobes, the angle formed by the projection line of the central sulcus and the upper horizontal is divided by a bisector. The gap is enclosed between the anterior and posterior vertical.

To determine the projection of the parietal-occipital sulcus, the projection line of the lateral fissure of the brain and the upper horizontal line are brought to the intersection with the sagittal line. The segment of the sagittal line enclosed between the two indicated lines is divided into three parts. The position of the furrow corresponds to the border between the upper and middle thirds.

Stereotactic method of encephalography (from the Greek. sterios- volumetric, spatial and taxis- location) is a set of techniques and calculations that allow, with great accuracy, the introduction of a cannula (electrode) into a predetermined, deeply located structure of the brain. To do this, it is necessary to have a stereotaxic device that compares the conditional coordinate points (systems) of the brain with the coordinate system of the apparatus, an accurate anatomical determination of intracerebral landmarks, and stereotaxic atlases of the brain.

The stereotaxic apparatus opened up new prospects for studying the most difficult (subcortical and stem) brain structures to study their function or for devitalization in certain diseases, for example, destruction of the ventrolateral nucleus of the thalamus in Parkinson's disease. The device consists of three parts - a basal ring, a guide wire with an electrode holder, and a phantom ring with a coordinate system. First, the surgeon determines the surface (bone) landmarks, then conducts a pneumoencephalogram or ventriculogram in two main projections. According to these data, in comparison with the coordinate system of the apparatus, the exact localization of intracerebral structures is determined.

On the inner base of the skull, there are three stepped cranial fossae: anterior, middle, and posterior (fossa cranii anterior, media, posterior). The anterior fossa is delimited from the middle one by the edges of the small wings of the sphenoid bone and the bone roller (limbus sphenoidalis) lying anterior to the sulcus chiasmatis; the middle fossa is separated from the posterior back of the sella turcica and by the upper edges of the pyramids of both temporal bones.

The anterior cranial fossa (fossa cranii anterior) is located above the nasal cavity and both eye sockets. The most anterior part of this fossa borders on the frontal sinuses at the transition to the cranial vault.

The frontal lobes of the brain are located within the fossa. On the sides of the crista galli are the olfactory bulbs (bulbi olfactorii); olfactory tracts begin from the latter.

Of the holes in the anterior cranial fossa, the foramen caecum is located most anteriorly. This includes a process of the dura mater with an inconstant emissary connecting the veins of the nasal cavity with the sagittal sinus. Behind this hole and on the sides of the crista galli are the holes of the perforated plate (lamina cribrosa) of the ethmoid bone, passing nn.olfactorii and a.ethmoidalis anterior from a.ophthalmica, accompanied by the vein and nerve of the same name (from the first branch of the trigeminal).

For most fractures in the region of the anterior cranial fossa, the most characteristic sign is bleeding from the nose and nasopharynx, as well as vomiting of swallowed blood. Bleeding can be moderate if the vasa ethmoidalia is ruptured, or severe if the cavernous sinus is damaged. Equally frequent are hemorrhages under the conjunctiva of the eye and eyelid and under the skin of the eyelid (a consequence of damage to the frontal or ethmoid bone). With abundant hemorrhage in the fiber of the orbit, a protrusion of the eyeball (exophthalmus) is observed. The outflow of cerebrospinal fluid from the nose indicates a rupture of the spurs of the meninges that accompany the olfactory nerves. If the frontal lobe of the brain is also destroyed, then particles of the medulla can come out through the nose.

If the walls of the frontal sinus and the cells of the ethmoid labyrinth are damaged, air may escape into the subcutaneous tissue (subcutaneous emphysema) or into the cranial cavity, extra or intradurally (pneumocephalus).

Damage nn. olfactorii causes olfactory disorders (anosmia) of varying degrees. Violation of the functions of the III, IV, VI nerves and the first branch of the V nerve depends on the accumulation of blood in the fiber of the orbit (strabismus, pupillary changes, anesthesia of the forehead skin). As for the second nerve, it can be damaged by a fracture of the processus clinoideus anterior (on the border with the middle cranial fossa); more often there is hemorrhage in the sheath of the nerve.

Purulent inflammatory processes that affect the contents of the cranial fossae are often the result of the transition of the purulent process from the cavities adjacent to the base of the skull (eye socket, nasal cavity and paranasal sinuses, inner and middle ear). In these cases, the process can spread in several ways: contact, hematogenous, lymphogenous. In particular, the transition of a purulent infection to the contents of the anterior cranial fossa is sometimes observed as a result of empyema of the frontal sinus and bone destruction: this may develop meningitis, epi- and subdural abscess, abscess of the frontal lobe of the brain. Such an abscess develops as a result of the spread of a purulent infection from the nasal cavity along the nn.olfactorii and tractus olfactorius, and the presence of connections between the sinus sagittalis superior and the veins of the nasal cavity makes it possible for the infection to pass to the sagittal sinus.

The central part of the middle cranial fossa (fossa cranii media) is formed by the body of the sphenoid bone. It contains a sphenoid (otherwise - the main) sinus, and on the surface facing the cranial cavity it has a recess - the fossa of the Turkish saddle, in which the cerebral appendage (pituitary gland) is located. Throwing over the fossa of the Turkish saddle, the dura mater forms the diaphragm of the saddle (diaphragma sellae). In the center of the latter there is a hole that passes a funnel (infundibulum) that connects the pituitary gland with the base of the brain. Anterior to the Turkish saddle, in sulcus chiasmatis, is the optic chiasm.

In the lateral sections of the middle cranial fossa, formed by the large wings of the sphenoid bones and the anterior surfaces of the pyramids of the temporal bones, are the temporal lobes of the brain. In addition, on the anterior surface of the pyramid of the temporal bone (on each side) at its apex (in the impressio trigemini) is the semilunar ganglion of the trigeminal nerve. The cavity in which the node (cavum Meckeli) is placed is formed by a bifurcation of the dura mater. Part of the anterior surface of the pyramid forms the upper wall of the tympanic cavity (tegmen tympani).

Within the middle cranial fossa, on the sides of the sella turcica lies one of the most important practical sinuses of the dura mater - the cavernous (sinus cavernosus), into which the superior and inferior ophthalmic veins flow.

From the openings of the middle cranial fossa, the canalis opticus (foramen opticum - BNA) lies most anteriorly, along which the n.opticus (II nerve) and a.ophathlmica pass into the orbit. Between the small and large wing of the sphenoid bone, fissura orbitalis superior is formed, through which the vv.ophthalmicae (superior et inferior) flow into the sinus cavernosus, and the nerves: n.oculomotorius (III nerve), n.trochlearis (IV nerve), n. ophthalmicus (first branch of the trigeminal nerve), n.abducens (VI nerve). Immediately posterior to the superior orbital fissure lies the foramen rotundum, which passes n.maxillaris (the second branch of the trigeminal nerve), and posterior and somewhat laterally from the round opening is the foramen ovale, through which the n.mandibularis (third branch of the trigeminal nerve) and the veins connecting the plexus pass venosus pterygoideus with sinus cavernosus. Behind and outward from the foramen ovale is the foramen spinosus, which passes a.meningei media (a.maxillaris). Between the top of the pyramid and the body of the sphenoid bone is foramen lacerum, made of cartilage, through which passes n.petrosus major (from n.facialis) and often an emissary that connects the plexus pterygoideus with the sinus cavernosus. The canal of the internal carotid artery also opens here.

With injuries in the region of the middle cranial fossa, as with fractures in the region of the anterior cranial fossa, bleeding from the nose and nasopharynx is observed. They arise as a result of either fragmentation of the body of the sphenoid bone, or due to damage to the cavernous sinus. Damage to the internal carotid artery that runs inside the cavernous sinus usually leads to fatal bleeding. There are cases when such heavy bleeding does not immediately occur, and then the clinical manifestation of damage to the internal carotid artery inside the cavernous sinus is pulsating bulging. It depends on the fact that blood from the damaged carotid artery penetrates into the ophthalmic vein system.

With a fracture of the pyramid of the temporal bone and a rupture of the tympanic membrane, bleeding from the ear appears, and if the spurs of the meninges are damaged, cerebrospinal fluid flows out of the ear. When the temporal lobe is crushed, particles of the medulla may come out of the ear.

In case of fractures in the area of ​​the middle cranial fossa, the VI, VII and VIII nerves are often damaged, resulting in internal strabismus, paralysis of the mimic muscles of the face, loss of auditory function on the side of the lesion.

As for the spread of the purulent process to the contents of the middle cranial fossa, it can be involved in the purulent process when the infection passes from the orbit, paranasal sinuses and the walls of the middle ear. An important pathway for the spread of purulent infection is vv.ophthalmicae, the defeat of which leads to thrombosis of the cavernous sinus and impaired venous outflow from the orbit. The consequence of this is swelling of the upper and lower eyelids and protrusion of the eyeball. Thrombosis of the cavernous sinus is sometimes also reflected in the nerves passing through the sinus or in the thickness of its walls: III, IV, VI and the first branch of V, more often on the VI nerve.

Part of the anterior face of the pyramid of the temporal bone forms the roof of the tympanic cavity - tegmen tympani. If the integrity of this plate is violated, as a result of chronic suppuration of the middle ear, an abscess can form: either epidural (between the dura mater and bone) or subdural (under the dura mater). Sometimes diffuse purulent meningitis or abscess of the temporal lobe of the brain also develops. The canal of the facial nerve adjoins the inner wall of the tympanic cavity. Often the wall of this canal is very thin, and then the inflammatory purulent process of the middle ear can cause paresis or paralysis of the facial nerve.

Contents of the posterior cranial fossa(fossa cratiii posterior) are the bridge and the medulla oblongata, located in the anterior part of the fossa, on the slope, and the cerebellum, which performs the rest of the fossa.

Of the sinuses of the dura mater, located in the posterior cranial fossa, the most important are the transverse, passing into the sigmoid sinus, and the occipital.

The openings of the posterior cranial fossa are arranged in a certain sequence. Most anteriorly, on the posterior face of the pyramid of the temporal bone lies the internal auditory opening (porus acusticus internus). A.labyrinthi (from the a.basilaris system) and nerves pass through it - facialis (VII), vestibulocochlearis (VIII), intermedius. Next in the posterior direction is the jugular foramen (foramen jugulare), through the anterior section of which the nerves pass - glossopharyngeus (IX), vagus (X) and accessorius Willisii (XI), through the posterior section - v.jugularis interna. The central part of the posterior cranial fossa is occupied by a large occipital foramen (foramen occipitale magnum), through which the medulla oblongata passes with its membranes, aa. vertebrales (and their branches - aa. spinales anteriores et posteriores), plexus venosi vertebrales interni and spinal roots of the accessory nerve ( n.accessorius). To the side of the foramen magnum is the foramen canalis hypoglossi, through which the n.hypoglossus (XII) and 1-2 veins pass, connecting the plexus venosus vertebralis internus and v.jugularis interna. In the sigmoid groove or next to it is v. emissaria mastoidea, which connects the occipital vein and the veins of the external base of the skull with the sigmoid sinus.

Fractures in the region of the posterior cranial fossa can cause subcutaneous hemorrhages behind the ear associated with damage to the sutura mastoideooccipitalis. These fractures often do not produce external bleeding, because the eardrum remains intact. The outflow of cerebrospinal fluid and the release of particles of the medulla in closed fractures are not observed (there are no channels that open outwards).

Within the posterior cranial fossa, a purulent lesion of the S-shaped sinus (sinus phlebitis, sinus thrombosis) can be observed. More often, it is involved in the purulent process by contact with inflammation of the cells of the mastoid part of the temporal bone (purulent mastoiditis), but there are also cases of the transition of the purulent process to the sinus with damage to the inner ear (purulent labyrinthitis). A thrombus that develops in the S-shaped sinus may reach the jugular foramen and pass to the bulb of the internal jugular vein. In this case, sometimes there is involvement in the pathological process of the IX, X, and XI nerves passing in the vicinity of the bulb (swallowing disorder due to paralysis of the palatine curtain and pharyngeal muscles, hoarseness, shortness of breath and slowing of the pulse, convulsions of the sternocleidomastoid and trapezius muscles) . Thrombosis of the S-shaped sinus can also spread to the transverse sinus, which is connected by anastomoses with the sagittal sinus and with the superficial veins of the hemisphere. Therefore, the formation of blood clots in the transverse sinus can lead to abscess of the temporal or parietal lobe of the brain.

A suppurative process in the inner ear can also cause diffuse inflammation of the meninges (purulent leptomeningitis) due to the presence of a message between the subarachnoid space of the brain and the perilymphatic space of the inner ear. With a breakthrough of pus from the inner ear into the posterior cranial fossa through the destroyed posterior face of the pyramid of the temporal bone, a cerebellar abscess may develop, which often occurs by contact and with purulent inflammation of the cells of the mastoid process. The nerves passing through the porus acusticus internus can also be conductors of infection from the inner ear.

PRINCIPLES OF SURGERY IN THE CRANIAL CAVITY

Puncture of the large occipital cistern (suboccipital puncture).

Indications. Suboccipital puncture is performed for diagnostic purposes to study the cerebrospinal fluid at this level and to introduce oxygen, air or contrast agents (lipiodol, etc.) into a large tank for the purpose of X-ray diagnostics (pneumoencephalography, myelography).

For therapeutic purposes, suboccipital puncture is used to administer various medicinal substances.

Preparation and position of the patient. The neck and the lower part of the scalp are shaved and the surgical field is treated as usual. The position of the patient is often lying on his side with a roller under his head so that the occipital protuberance and the spinous processes of the cervical and thoracic vertebrae are in line. The head is tilted forward as much as possible. This increases the distance between the arch of the I cervical vertebra and the edge of the foramen magnum.

Operation technique. The surgeon gropes for the protuberantia occipitalis externa and the spinous process of the II cervical vertebra and in this area performs soft tissue anesthesia with 5-10 ml of a 2% novocaine solution. Exactly in the middle of the distance between the protuberantia occipitalis externa and the spinous process of the II cervical vertebra. A special needle with a mandrin makes an injection along the midline in an oblique upward direction at an angle of 45-50 ° until the needle stops in the lower part of the occipital bone (depth 3.0-3.5 cm). When the tip of the needle has reached the occipital bone, it is slightly pulled back, the outer end is raised and again advanced deep into the bone. Repeating this manipulation several times, gradually, sliding along the scales of the occipital bone, they reach its edge, move the needle forward, pierce the membrana atlantooccipitalis posterior.

The appearance of drops of cerebrospinal fluid after removing the mandrin from the needle indicates its passage through the dense atlanto-occipital membrane and entering the large cistern. When liquor with blood enters from the needle, the puncture must be stopped. The depth to which the needle must be immersed depends on the age, sex, constitution of the patient. The average puncture depth is 4-5 cm.

To protect against the danger of damage to the medulla oblongata, a special rubber nozzle is put on the needle according to the permissible immersion depth of the needle (4-5 cm).

Cisternal puncture is contraindicated in tumors located in the posterior cranial fossa and in the upper cervical region of the spinal cord.

Puncture of the ventricles of the brain (ventriculopuncture).

Indications. Ventricular puncture is performed for diagnostic and therapeutic purposes. Diagnostic puncture is used to obtain ventricular fluid for the purpose of its study, to determine intraventricular pressure, to introduce oxygen, air or contrast agents (lipiodol, etc.).

Therapeutic ventriculopuncture is indicated if urgent unloading of the cerebrospinal fluid system is necessary in case of symptoms of its blockade, in order to drain fluid from the ventricular system for a longer time, i.e. for long-term drainage of the cerebrospinal fluid system, as well as for the introduction of drugs into the ventricles of the brain.

Puncture of the anterior horn of the lateral ventricle of the brain

For orientation, first draw a midline from the bridge of the nose to the occiput (corresponds to the sagittal suture) (Fig. 7A,B). Then a line of the coronal suture is drawn, located 10-11 cm above the superciliary arch. From the intersection of these lines, 2 cm to the side and 2 cm anterior to the coronal suture, points for craniotomy are marked. A linear incision of soft tissues 3-4 cm long is carried out parallel to the sagittal suture. The periosteum is exfoliated with a raspator and a hole in the frontal bone is drilled with a cutter at the intended point. Having cleaned the edges of the hole in the bone with a sharp spoon, a 2 mm long incision in the dura mater is made in the avascular area with a sharp scalpel. Through this incision, a special blunt cannula with holes on the sides is used to puncture the brain. The cannula is advanced strictly parallel to the greater falciform process with an inclination in the direction of the biauricular line (a conditional line connecting both auditory canals) to a depth of 5-6 cm, which is taken into account on a scale printed on the surface of the cannula. When the required depth is reached, the surgeon fixes the cannula well with his fingers and removes the mandrin from it. The fluid is normally clear and is released in rare drops. With dropsy of the brain, the cerebrospinal fluid sometimes flows in a jet. After removing the required amount of CSF, the cannula is removed and the wound is sutured tightly.

Rice. 7. Scheme of puncture of the anterior and posterior horns of the lateral ventricle of the brain.

A - the location of the burr hole in relation to the coronal and sagittal sutures outside the projection of the sagittal sinus;

B - the needle was passed through the burr hole to a depth of 5-6 cm in the direction of the biauricular line;

C - the location of the burr hole in relation to the midline and the level of the occiput (the direction of the needle stroke is indicated in the frame);

D - the needle was passed through the burr hole into the posterior horn of the lateral ventricle. (From: Gloomy V.M., Vaskin I.S., Abrakov L.V. Operative neurosurgery. - L., 1959.)

Puncture of the posterior horn of the lateral ventricle of the brain

The operation is performed according to the same principle as the puncture of the anterior horn of the lateral ventricle (Fig. 7 C, D). First, a point is set located 3-4 cm above the occipital buff and 2.5-3.0 cm from the midline to the left or right. It depends on which ventricle is planned to be punctured (right or left).

Having made a burr hole at the indicated point, the dura mater is dissected over a short distance, after which the cannula is inserted and advanced anteriorly by 6-7 cm in the direction of an imaginary line passing from the injection site to the upper outer edge of the orbit of the corresponding side.

Stop bleeding from the venous sinuses.

With penetrating wounds of the skull, dangerous bleeding from the venous sinuses of the dura mater is sometimes observed, most often from the superior sagittal sinus and less often from the transverse sinus. Depending on the nature of the sinus injury, various methods of stopping bleeding are used: tamponade, suturing, and sinus ligation.

Tamponade of the superior sagittal sinus.

The primary surgical treatment of the wound is performed, while a sufficiently wide (5-7 cm) burr hole is made in the bone so that intact areas of the sinus are visible. When bleeding occurs, the hole in the sinus is pressed down with a swab. Then they take long gauze tapes, which are methodically laid in folds over the bleeding site. Tampons are inserted on both sides of the site of sinus injury, laying them between the inner plate of the skull bone and the dura mater. Tampons press the upper wall of the sinus against the lower one, causing it to collapse and subsequently form a blood clot in this place. Swabs are removed after 12-14 days.

With small defects in the outer wall of the venous sinus, the wound can be closed with a piece of muscle (for example, temporal) or a plate of galea aponeurotica, which is sutured with separate frequent or, better, continuous sutures to the dura mater. In some cases, it is possible to close the sinus wound with a flap cut from the outer layer of the dura mater according to Burdenko. The imposition of a vascular suture on the sinus is possible only with small linear ruptures of its upper wall.

If it is impossible to stop the bleeding by the above methods, both ends of the sinus are tied with strong silk ligatures on a large round needle.

Ligation of the superior sagittal sinus.

Temporarily restraining bleeding by pressing with the index finger or a swab, quickly expand the defect in the bone with nippers so that the upper longitudinal sinus is open to a sufficient extent. After that, 1.5-2.0 cm away from the midline, the dura mater is incised on both sides parallel to the sinus anteriorly and posteriorly from the injury site. Two ligatures are passed through these incisions with a thick, steeply curved needle to a depth of 1.5 cm and the sinus is ligated. Then ligate all the veins that flow into the damaged area of ​​the sinus.

Dressing a. meningea media.

Indications. Closed and open injuries of the skull, accompanied by injury to the artery and the formation of an epidural or subdural hematoma.

The projection of the branches of the middle meningeal artery is determined on the basis of the Krenlein scheme. According to the general rules of trepanation of the skull, a horseshoe-shaped skin-aponeurotic flap with a base on the zygomatic arch is cut out in the temporal region (on the damaged side) and scalped from top to bottom. After that, the periosteum is dissected within the skin wound, several holes are drilled in the temporal bone with a cutter, a musculoskeletal flap is formed and it is broken at the base. A swab removes blood clots and looks for a bleeding vessel. Having found the place of damage, they capture the artery above and below the wound with two clamps and tie it with two ligatures. In the presence of a subdural hematoma, the dura mater is dissected, blood clots are carefully removed with a stream of saline, the cavity is drained and hemostasis is performed. Sutures are applied to the dura mater. The flap is placed in place and the wound is sutured in layers.

Theoretical questions for the lesson:

1. The inner surface of the base of the skull.

2. Shells of the brain.

3. Venous sinuses of the dura mater.

4. Craniocerebral topography.

5. Clinic of skull base fractures.

6. Surgical interventions on the internal structures of the cranial cavity: indications, anatomical justification, technique.

Practical part of the lesson:

1. Be able to determine the main landmarks and boundaries of the base of the skull.

2. Master the construction of the scheme of the cranial topography of Krenlein and determine the projection of intracranial formations (sulci, middle meningeal artery).

Questions for self-control of knowledge

1. Name the boundaries and landmarks of the base of the skull.

2. What are the anterior, middle and posterior cranial fossae formed by?

3. What are the "weak points" of the base of the skull?

4. What is the ratio of the dura mater to the bones of the vault and base of the skull?

5. What sinuses of the dura mater belong to the sinuses of the vault and base of the skull?

6. How is the connection of the venous sinuses with extracranial veins?

7. What are the features of the distribution of the nature of hematomas in the intershell spaces?

8. What is the purpose of Kreinlein's craniocerebral topography scheme?

Rhomboid brain (- bridge, medulla oblongata). Between the rhomboid and midbrain is the isthmus of the rhomboid brain.

The brain is located in the cranial cavity. It has a convex upper-lateral surface and a lower surface and a flattened one - the base of the brain.

The mass of the brain of an adult is from 1100 to 2000 grams; from 20 to 60 years, the mass m and volume V remain maximum and constant, after 60 years it decreases slightly. Neither the absolute nor the relative mass of the brain is an indicator of the degree of mental development. Turgenev's brain mass was 2012, Byron's - 2238, Cuvier's - 1830, Schiller's - 1871, Mendeleev's - 1579, Pavlov's - 1653. The brain consists of bodies of neurons, nerve tracts and blood vessels. The brain consists of 3 parts: the cerebrum and the brain stem.

The cerebral hemispheres reach their maximum development in humans, later than other departments.

The large brain consists of - right and left, which are connected to one another by a thick commissure (commissure) - the corpus callosum. The right and left hemispheres are divided by a longitudinal fissure. Under the commissure there is an arch, which is two curved fibrous strands, which are interconnected in the middle part, and diverge in front and behind, forming pillars and legs of the arch. In front of the pillars of the vault is the anterior commissure. Between the corpus callosum and the arch is a thin vertical plate of brain tissue - a transparent septum.

The hemispheres have superior lateral, medial, and inferior surfaces. The upper lateral is convex, the medial is flat, facing the same surface of the other hemisphere, and the lower is irregular in shape. On three surfaces there are deep and shallow furrows, and between them are convolutions. Furrows are depressions between convolutions. Convolutions - elevations of the medulla.

The surfaces of the cerebral hemispheres are separated from each other by edges - the upper, lower lateral and lower vertical. In the space between the two hemispheres, the crescent of the cerebrum enters - a large sickle-shaped process, which is a thin plate of the hard shell that penetrates into the longitudinal fissure of the cerebrum, without reaching the corpus callosum, and separates the right and left hemispheres from each other. The most protruding parts of the hemispheres are called poles: frontal, occipital and temporal. The relief of the surfaces of the cerebral hemispheres is very complex and is due to the presence of more or less deep furrows of the cerebral cortex and ridge-like elevations located between them - convolutions. The depth, length of some furrows and convolutions, their shape and direction are very variable.

Each hemisphere is divided into lobes - frontal, parietal, occipital, insular. The central sulcus (Roland's sulcus) separates from the parietal, the lateral sulcus (Sylvian sulcus) separates the temporal from the frontal and parietal, the parietal-occipital sulcus separates the parietal and occipital lobes. The lateral sulcus is laid by the 4th month of intrauterine development, the parieto-occipital and central - by the 6th month. In the prenatal period, gyrification occurs - the formation of convolutions. These three furrows appear first and are of great depth. Soon, a couple more parallel to it are added to the central furrow: one passes in front of the central one and, accordingly, is called precentral, which splits into two - upper and lower. Another furrow is located behind the central and is called postcentral.

The postcentral sulcus lies behind and nearly parallel to the central sulcus. Between the central and postcentral sulci is the postcentral gyrus. At the top, it passes to the medial surface of the cerebral hemisphere, where it connects with the precentral gyrus of the frontal lobe, forming with it the paracentral lobule. On the upper lateral surface of the hemisphere, below, the postcentral gyrus also passes into the precentral gyrus, covering the central sulcus from below. It is parallel to the upper edge of the hemisphere. Above the intraparietal sulcus is a group of small convolutions, called the superior parietal lobule. Below this groove lies the inferior parietal lobule, within which two convolutions are distinguished: supramarginal and angular. The supramarginal gyrus covers the end of the lateral sulcus, and the angular gyrus covers the end of the superior temporal sulcus. The lower part of the inferior parietal lobule and the lower sections of the postcentral gyrus adjacent to it, in place with the lower part of the precentral gyrus, hanging over the insular lobe, form the fronto-parietal operculum of the insula.

The surface of the cerebrum is covered with grooves dividing it into convolutions. Furrows are divided into primary, secondary and tertiary. Primary furrows are constant, deep, appear early in the process of ontogenesis. Secondary furrows are also constant, but more variable in configuration and appear later. Tertiary furrows are unstable, very variable in shape, length and direction. In addition, part of the furrows (fissuarae) presses the brain wall into the cavity of the lateral ventricle, forming protrusions in it (spur, collateral, hippocampal fissures), while others (sulci) cut through only the cerebral cortex. The hemisphere is divided by deep furrows into lobes: frontal, parietal, temporal, occipital and insular.

Outer surface of the hemisphere(Fig. 1). The largest furrow is lateral (sylvian; sulcus lateralis; Fig. 1 and 6, fS) - in the early stages of development it is a hole, the edges of which converge later, but its bottom remains wide in the adult and forms an island (insula). The lateral groove originates at the base of the hemisphere; on its outer surface, it is divided into three branches: two short ones - anterior horizontal (h, Fig. 1) and ascending (r, Fig. 1) and a very long posterior horizontal, heading gently backwards and upwards and at the posterior end is divided into ascending and descending branch. The island occupying the bottom of the lateral groove forms a protrusion (pole) directed outwards and downwards, passing on the base of the brain into the threshold of the islet, or the transverse gyrus (limen, s. gyrus transversa insulae); in front, above and behind the island is separated by a deep circular groove (sulcus circularis insulae; Fig. 2) from the adjacent parts of the frontal, parietal and temporal lobes, forming a tire (operculum frontale, frontoparietale, temporale). The obliquely running central sulcus of the insula divides it into anterior and posterior lobules (Fig. 2).

Rice. 1. Furrows and gyri of the outer surface of the left hemisphere of the large brain: Ang - angular gyrus; Ca - anterior central gyrus; se - central sulcus; Cp - posterior central gyrus; f1 - superior frontal sulcus; F1 - superior frontal gyrus; fm - middle frontal sulcus; F2 - middle frontal gyrus; f2 - lower frontal sulcus; F3o - orbital part of the inferior frontal gyrus; F 3or - opercular part of the inferior frontal gyrus; Fst - triangular part of the inferior frontal gyrus; fS - lateral furrow; Gsm - supramarginal gyrus; h - anterior horizontal branch of the lateral groove; ip - interparietal sulcus; O1 - superior occipital gyrus; OpR - central tire; RT - temporal pole; spo - postcentral furrow; spr - precentral sulcus; t1 - superior temporal sulcus; T1 - superior temporal gyrus; t2 - middle temporal sulcus; T2 - middle temporal gyrus; T3 - inferior temporal gyrus; σ - anterior ascending branch of the lateral sulcus.

Rice. 2. Furrows of the outer surface of the island (scheme): s.c.i.a. - anterior circular furrow; s.c.i.s. - superior circular sulcus; s.c.i.p. - posterior circular sulcus; s.c.i. - central sulcus of the islet; spi - postcentral sulcus of the islet; s.pr.i. - precentral sulcus of the islet; s.b.I and s.b.II - short furrows of the island; 13, 13i, 14a, 14m, 14p, ii, ii° - cytoarchitectonic fields of the islet (I. Stankevich).

The second large furrow on the outer surface of the hemisphere - the central one (Roland's; sulcus centralis; ce, Fig. 1 and 5) - cuts through the upper edge of the hemisphere (ce, Fig. 4), along its outer surface it stretches down and forward, slightly not reaching the lateral furrows.

frontal lobe(lobus frontalis) behind is limited to the central, from below - the lateral groove. Anterior to the central sulcus and parallel to it are the upper and lower precentral sulci (sulci precentrales; spr, Fig. 1 and 5). Between them and the central sulcus is the anterior central gyrus (gyrus centralis ant .; Ca, Fig. 1), which goes down into the tire (OpR, Fig. 1), and up to the anterior section of the paracentral lobule (Ra, Fig. 4) . From both precentral sulci, the upper and lower frontal sulci (sulci frontales; f1 and f2, Fig. 1) depart anteriorly almost at a right angle, limiting the three frontal gyrus - the upper (F1, Fig. 1), middle (F2, Fig. 1) and lower (F3, Fig. 1); the latter is divided into three parts: opercular (F3 op, Fig. 1), triangular (F3 t, Fig. 1), and orbital (F3 o, Fig. 1).

The parietal lobe (lobus parietalis) is bounded in front by the central sulcus, from below by the lateral, behind by the parietal-occipital and transverse occipital sulci. Parallel to the central sulcus and posterior to it is the postcentral sulcus (sulcus postcentralis; spo, Figs. 1 and 5), often divided into upper and lower sulci. Between it and the central sulcus is the posterior central gyrus (gyrus centralis post.; Cf., Fig. 1 and 5). Often (but not always) the interparietal sulcus (sulcus iaterparietalis, ip, Fig. 1 and 5) is connected to the postcentral sulcus, which goes arcuately posteriorly. It divides the parietal lobe into superior and inferior parietal lobules (lobuli parietales sup. et inf.). The composition of the inferior parietal lobule includes the supramarginal gyrus (gyrus supramarginalis, Gsm, Fig. 1), surrounding the ascending branch of the lateral sulcus, and from it posteriorly, the angular gyrus (gyrus angularis, Ang, Fig. 1), surrounding the ascending branch of the superior temporal sulcus.

The temporal lobe (lobus temporalis) is bounded from above by the lateral groove, and in the posterior section by a line connecting the posterior end of the lateral groove with the lower end of the transverse occipital groove. On the outer surface of the temporal lobe, there are superior, middle, and inferior temporal sulci (t1, t2, and t3), limiting three longitudinally located temporal gyri (T1, T2, and T3, Figs. 1 and 6). The upper surface of the superior temporal gyrus forms the lower wall of the lateral sulcus (Fig. 3) and is divided into two parts: a large, opercular, covered with parietal operculum, and a smaller anterior, insular.

Occipital lobe (lobus occipitalis). Furrows and convolutions on the outer surface of the occipital lobe are very unstable. The most constant superior occipital gyrus. On the border of the parietal lobe and the occipital lobe there are several transitional gyri. The first surrounds the lower end of the parietal-occipital sulcus that extends to the outer surface of the hemisphere. In the posterior part of the occipital lobe there are one or two polar grooves (sulci polares), which have a vertical direction and limit the descending occipital gyrus (gyrus occipitalis descendens) at the occipital pole.

Inner surface of the hemisphere(Fig. 4). The central position is occupied by the sulcus of the corpus callosum (sulcus corporis callosi; see, Fig. 4). Posteriorly, it passes into the hippocampal groove (sulcus hippocampi), which protrudes the wall of the brain into the cavity of the lower horn of the lateral ventricle in the form of an ammon horn (hippocampus). Concentric to the sulcus of the corpus callosum, there is also an arched cingulate, or corpus callosum, sulcus (sulcus cinguli cmg, Fig. 4), and then a posterior subparietal sulcus (sulcus subparietalis; ssp, Fig. 4). On the inner surface of the temporal lobe, parallel to the hippocampal sulcus, there is a rhinal sulcus (sulcus rhinalis; rh, Fig. 6). The cingulate, subtopic, and rhinal sulci delimit the limbic gyrus (gyrus limbicus) from above. Its upper part, located above the corpus callosum, is designated as the cingulate gyrus (gyrus cinguli; L, Fig. 4), and the lower part, located between the hippocampal and rhinal grooves, is referred to as the hippocampal gyrus (gyrus hippocampi; Hi, Fig. 4 and 6) . In the anterior section of the hippocampal gyrus, it bends posteriorly, forming the uncinate gyrus (uncus; V, Fig. 4). Outside the limbic gyrus, on the inner surface of the hemisphere, there are gyruses that pass to it from the outer surface of the frontal, parietal and occipital lobes. In the back of the inner surface of the hemisphere, there are two very deep furrows - parietal-occipital (sulcus parieto-occipitalis; po, Fig. 4 and 5) and spur (sulcus calcarinus; C, Fig. 4 and 6). The parietal-occipital sulcus also extends to the outer surface, only slightly not reaching the interparietal sulcus here. Between it and the marginal branch of the cingulate sulcus is a quadrangular gyrus - the precuneus (precuneus; Pr, Fig. 4), anterior to which is the paracentral lobule (Ra, Fig. 4). The spur groove has a longitudinal direction, goes anteriorly from the occipital pole, connects at an acute angle with the parietal-occipital groove and continues further as a trunk (Tr, Fig. 4), ending under the posterior end of the corpus callosum. Between the spur and parietal-occipital grooves lies the sphenoid gyrus (cuneus; Cu, Fig. 4).

Inferior surface of the hemisphere(Fig. 6) is mainly occupied by formations of the frontal, temporal, and occipital lobes that extend onto it from the outer and inner surfaces. These do not include only formations that are part of the so-called olfactory brain (rhinencephalon), the furrows and convolutions of which are clearly visible on the intact hemisphere only in ontogenesis (see Architectonics of the cerebral cortex, Fig. 1). On the lower surface of the frontal lobe, there is an olfactory groove (sulcus olfactorius), occupied by the olfactory bulb and olfactory tract, medially from it there is a direct gyrus (gyrus rectus), and outwardly - orbital grooves (sulci orbitales) that are very variable in shape. The convolutions located between them are also called orbital (gyri orbitales). On the lower surface of the temporal lobe, the inferior temporal sulcus is visible outwards (t3, Fig. 6). A deep occipital-temporal, or collateral, groove (sulcus collateralis; ot, Fig. 6) passes medially from it. Between these grooves is the lateral occipitotemporal fusiform gyrus (gyrus occipito-temporalis lat., S. fusiformis; Fus, Fig. 6). Between the occipital-temporal and spur grooves is the lingual gyrus (gyrus occipito-temporalis med., S. lingualis; Lg, Fig. 6). See also Brain.

14.1. GENERAL PROVISIONS

End brain (telencephalon), or big brain (cerebrum), located in the supratentorial space of the cranial cavity consists of two large

hemispheres (gemispherium cerebralis),separated by a deep longitudinal slit (fissura longitudinalis cerebri), in which the crescent of the brain is immersed (falx cerebri) representing a duplication of the dura mater. The large hemispheres of the brain make up 78% of its mass. Each of the cerebral hemispheres has lobes: frontal, parietal, temporal, occipital and limbic. They cover the structures of the diencephalon and the brain stem and cerebellum located below the cerebellar mantle (subtentorially).

Each of the cerebral hemispheres has three surfaces: upper lateral, or convexital (Fig. 14.1a), - convex, facing the bones of the cranial vault; internal (Fig. 14.1b), adjacent to the large falciform process, and lower, or basal (Fig. 14.1c), repeating the relief of the base of the skull (anterior and middle pits) and the cerebellar tenon. In each hemisphere, three edges are distinguished: upper, lower inner and lower outer, and three poles: anterior (frontal), posterior (occipital) and lateral (temporal).

The cavity of each cerebral hemisphere is lateral ventricle of the brain while the left lateral ventricle is recognized as the first, the right - the second. The lateral ventricle has a central part located deep in the parietal lobe (lobus parietalis) and three horns extending from it: the anterior horn penetrates the frontal lobe (lobus frontalis), lower - to the temporal (lobus temporalis), posterior - in the occipital (lobus occipitalis). Each of the lateral ventricles communicates with the third ventricle of the brain through the interventricular hole Monroe.

The central sections of the medial surface of both hemispheres are interconnected by cerebral commissures, the most massive of which is the corpus callosum, and structures of the diencephalon.

The telencephalon, like other parts of the brain, consists of gray and white matter. Gray matter is located in the depths of each hemisphere, forming subcortical nodes there, and along the periphery of the free surfaces of the hemisphere, where it makes up the cerebral cortex.

The main issues related to the structure, functions of the basal ganglia and variants of the clinical picture when they are affected are discussed in chapters 5, 6. The cerebral cortex is approximately

Rice. 14.1.Hemispheres of the brain.

a - upper lateral surface of the left hemisphere: 1 - central sulcus; 2 - orbital part of the lower frontal gyrus; I - frontal lobe; 3 - precentral gyrus; 4 - precentral furrow; 5 - superior frontal gyrus; 6 - middle frontal gyrus; 7 - tegmental part of the inferior frontal gyrus; 8 - lower frontal gyrus; 9 - lateral furrow; II - parietal lobe: 10 - postcentral gyrus; 11 - postcentral furrow; 12 - intraparietal groove; 13 - supramarginal gyrus; 14 - angular gyrus; III - temporal lobe: 15 - superior temporal gyrus; 16 - upper temporal sulcus; 17 - middle temporal gyrus; 18 - middle temporal sulcus; 19 - lower temporal gyrus; IV - occipital lobe: b - medial surface of the right hemisphere: 1 - paracentral lobule, 2 - precuneus; 3 - parieto-occipital sulcus; 4 - wedge, 5 - lingual gyrus; 6 - lateral occipitotemporal gyrus; 7 - parahippocampal gyrus; 8 - hook; 9 - vault; 10 - corpus callosum; 11 - superior frontal gyrus; 12 - cingulate gyrus; c - lower surface of the cerebral hemispheres: 1 - longitudinal interhemispheric fissure; 2 - orbital furrows; 3 - olfactory nerve; 4 - optic chiasm; 5 - middle temporal sulcus; 6 - hook; 7 - lower temporal gyrus; 8 - mastoid body; 9 - base of the brain stem; 10 - lateral occipitotemporal gyrus; 11 - parahippocampal gyrus; 12 - collateral groove; 13 - cingulate gyrus; 14 - lingual gyrus; 15 - olfactory groove; 16 - direct gyrus.

3 times the surface of the hemispheres visible during external examination. This is due to the fact that the surface of the cerebral hemispheres is folded, has numerous depressions - furrows (sulci cerebri) and located between them convolutions (gyri cerebri). The cerebral cortex covers the entire surface of the convolutions and furrows (hence its other name is pallium - a cloak), while sometimes penetrating to a great depth into the substance of the brain.

The severity and location of the sulci and convolutions of the cerebral hemispheres are variable to a certain extent, but the main ones are formed in the process of ontogenesis and are constant, characteristic of each normally developed brain.

14.2. MAJOR GROOCHES AND GRIPS OF THE HEMISPHERES OF THE BRAIN

Upper lateral (convexital) surface of the hemispheres (Fig. 14.1a). The largest and deepest lateral furrow (sulcus lateralis),or sylvian furrow, - separates the frontal and anterior parts of the parietal lobe from the temporal lobe located below. The frontal and parietal lobes are separated central, or Roland, furrow(sulcus centralis), which cuts through the upper edge of the hemisphere and goes down and forward along its convexital surface, slightly short of the lateral groove. The parietal lobe is separated from the occipital lobe located behind it by the parietal-occipital and transverse occipital grooves passing along the medial surface of the hemisphere.

In the frontal lobe in front of the central gyrus and parallel to it is the precentral (gyrus precentralis), or anterior central, gyrus, which is bounded anteriorly by the precentral sulcus (sulcus precentralis). The superior and inferior frontal grooves depart anteriorly from the precentral sulcus, dividing the convexital surface of the anterior sections of the frontal lobe into three frontal gyrus - superior, middle and inferior (gyri frontales superior, media et inferior).

The anterior section of the convexital surface of the parietal lobe is located behind the central sulcus postcentral (gyrus postcentralis), or posterior central, gyrus. Behind it is bordered by the postcentral sulcus, from which the intraparietal sulcus stretches back. (sulcus intraparietalis), separating the superior and inferior parietal lobules (lobuli parietales superior et inferior). In the lower parietal lobule, in turn, the supramarginal gyrus is distinguished (gyrus supramarginalis), surrounding the posterior part of the lateral (Sylvian) groove, and the angular gyrus (girus angularis), bordering the back of the superior temporal gyrus.

On the convexital surface of the occipital lobe of the brain, the furrows are shallow and can vary significantly, as a result of which the nature of the convolutions located between them is also variable.

The convexital surface of the temporal lobe is divided by the superior and inferior temporal sulci, which are almost parallel to the lateral (Sylvian) sulcus, dividing the convexital surface of the temporal lobe into the superior, middle, and inferior temporal gyri (gyri temporales superior, media et inferior). The superior temporal gyrus forms the inferior lip of the lateral (Sylvian) sulcus. On its surface facing

side of the lateral furrow, there are several transverse small furrows, highlighting small transverse gyrus on it (gyrus of Geschl), which can be seen only by spreading the edges of the lateral furrow.

The anterior part of the lateral (Sylvian) groove is a depression with a wide bottom, forming the so-called island (insula) or insular lobe (lubus insularis). The upper edge of the lateral furrow covering this island is called tire (operculum).

Inner (medial) surface of the hemisphere (Fig. 14.1b). The central part of the inner surface of the hemisphere is closely connected with the structures of the diencephalon, from which it is delimited by those related to the large brain vault (fornix) and corpus callosum (corpus callosum). The latter is bordered on the outside by a furrow of the corpus callosum (sulcus corporis callosi), starting at the front of it - the beak (rostrum) and ending at its thickened rear end (splenium). Here, the sulcus of the corpus callosum passes into the deep hippocampal sulcus (sulcus hippocampi), which penetrates deep into the substance of the hemisphere, pressing it into the cavity of the lower horn of the lateral ventricle, as a result of which the so-called ammonium horn is formed.

Somewhat departing from the sulcus of the corpus callosum and the hippocampal sulcus, the corpus callosum, subparietal and nasal sulci are located, which are a continuation of each other. These grooves delimit from the outside the arcuate part of the medial surface of the cerebral hemisphere, known as limbic lobe(lobus limbicus). There are two convolutions in the limbic lobe. The upper part of the limbic lobe is the superior limbic (superior marginal), or girdle, gyrus (girus cinguli), the lower part is formed by the inferior limbic gyrus, or seahorse gyrus (girus hippocampi), or parahippocampal gyrus (girus parahypocampalis), in front of which there is a hook (uncus).

Around the limbic lobe of the brain are the formations of the inner surface of the frontal, parietal, occipital and temporal lobes. Most of the inner surface of the frontal lobe is occupied by the medial side of the superior frontal gyrus. On the border between the frontal and parietal lobes of the cerebral hemisphere is located paracentral lobule (lobulis paracentralis), which is, as it were, a continuation of the anterior and posterior central gyri on the medial surface of the hemisphere. On the border between the parietal and occipital lobes, the parietal-occipital sulcus is clearly visible. (sulcus parietooccipitalis). From the bottom of it departs back spur furrow (sulcus calcarinus). Between these deep furrows is a triangular gyrus, known as a wedge. (cuneus). In front of the wedge is a quadrangular gyrus, related to the parietal lobe of the brain, the precuneus.

Inferior surface of the hemisphere (Fig. 14.1c). The lower surface of the cerebral hemisphere consists of formations of the frontal, temporal and occipital lobes. The part of the frontal lobe adjacent to the midline is the direct gyrus (girus rectus). Outside, it is delimited by the olfactory groove (sulcus olfactorius), to which the formations of the olfactory analyzer are adjacent from below: the olfactory bulb and the olfactory tract. Lateral to it, up to the lateral (Sylvian) groove, which extends to the lower surface of the frontal lobe, there are small orbital gyri (gyri orbitalis). The lateral sections of the lower surface of the hemisphere behind the lateral sulcus are occupied by the inferior temporal gyrus. Medial to it is the lateral temporo-occipital gyrus. (gyrus occipitotemporalis lateralis), or fusiform groove. Before-

its inner parts border on the gyrus of the hippocampus, and the posterior ones - on the lingual (gyrus lingualis) or medial temporoccipital gyrus (gyrus occipitotemporalis medialis). The latter, with its posterior end, is adjacent to the spur groove. The anterior sections of the fusiform and lingual gyri belong to the temporal lobe, and the posterior sections to the occipital lobe of the brain.

14.3. WHITE MATTER OF THE GREAT HEMISPHERES

The white matter of the cerebral hemispheres consists of nerve fibers, mainly myelin, that make up pathways that provide connections between the neurons of the cortex and clusters of neurons that form the thalamus, subcortical nodes, and nuclei. The main part of the white matter of the cerebral hemispheres is located in its depth semi-oval center, or radiant crown (corona radiata), consisting mainly of afferent and efferent projection pathways connecting the cerebral cortex with subcortical nodes, nuclei and reticular substance of the diencephalon and brain stem, with segments of the spinal cord. They are especially compactly located between the thalamus and the subcortical nodes, where they form the internal capsule described in Chapter 3.

Nerve fibers that connect parts of the cortex of one hemisphere are called associative. The shorter these fibers and the connections they form, the more superficial they are; longer associative connections, located deeper, connect relatively distant parts of the cerebral cortex (Fig. 14.2 and 14.3).

The fibers that connect the cerebral hemispheres and therefore have a common transverse orientation are called commissural, or sleeping. Commissural fibers connect identical parts of the cerebral hemispheres, creating the possibility of combining their functions. They form three spikes large brain: the most massive of them - corpus callosum (corpus callosum), in addition, commissural fibers make up anterior commissure, located under the beak of the corpus callosum (rostrum corporis collosum) and connecting both olfactory regions, as well as commissure of the vault (commissura fornicis), or a hippocampal commissure formed by fibers connecting the structures of the ammon horns of both hemispheres.

In the anterior part of the corpus callosum there are fibers connecting the frontal lobes, then there are fibers connecting the parietal and temporal lobes, the posterior part of the corpus callosum connects the occipital lobes of the brain. The anterior commissure and commissure of the fornix mainly unite sections of the ancient and old cortex of both hemispheres; the anterior commissure, in addition, provides a connection between their middle and lower temporal gyri.

14.4. Olfactory system

In the process of phylogenesis, the development of the large brain is associated with the formation of the olfactory system, the functions of which contribute to the preservation of the viability of animals and are of no small importance for human life.

Rice. 14.2.Associative cortical-cortical connections in the cerebral hemispheres [according to V.P. Vorobyov].

1 - frontal lobe; 2 - knee of the corpus callosum; 3 - corpus callosum; 4 - arcuate fibers; 5 - upper longitudinal beam; 6 - cingulate gyrus; 7 - parietal lobe, 8 - occipital lobe; 9 - vertical bundles of Wernicke; 10 - roller of the corpus callosum;

11 - lower longitudinal beam; 12 - subcausal bundle (frontal-occipital lower bundle); 13 - vault; 14 - temporal lobe; 15 - hook of the gyrus of the hippocampus; 16 - hook bundles (fasciculus uncinatus).

Rice. 14.3.Myeloarchitectonics of the cerebral hemispheres.

1 - projection fibers; 2 - commissural fibers; 3 - associative fibers.

14.4.1. The structure of the olfactory system

The bodies of the first neurons of the olfactory system are located in the mucous membrane nose, mainly upper part of the nasal septum and upper nasal passage. Olfactory cells are bipolar. Their dendrites come to the surface of the mucous membrane and end here with specific receptors, and axons are grouped in the so-called olfactory filaments (filiolfactorii), the number of which on each side is about twenty. Such a bundle of olfactory filaments and makes up the I cranial, or olfactory, nerve(Fig. 14.4). These threads pass into the anterior (olfactory, olfactory) cranial fossa through the ethmoid bone and end at cells located here olfactory bulbs. The olfactory bulbs and the proximal olfactory tracts are, in fact, a consequence of the protrusions of the substance of the large brain formed in the process of ontogenesis and represent structures related to it.

The olfactory bulbs contain cells that are the bodies of the second neurons. olfactory pathway, whose axons form olfactory tracts (tracti olfactorii), located under the olfactory grooves, lateral to the direct convolutions located on the basal surface of the frontal lobes. Olfactory tracts are directed backward to the subcortical olfactory centers. Approaching the anterior perforated plate, the fibers of the olfactory tract are divided into medial and lateral bundles, forming an olfactory triangle on each side. Later, these fibers are suitable to the bodies of the third neurons of the olfactory analyzer, located

Rice. 14.4.Olfactory analyzer.

1 - olfactory cells; 2 - olfactory threads (in total they make up the olfactory nerves); 3 - olfactory bulbs; 4 - olfactory tracts; 5 - olfactory triangles; 6 - parahippocampal gyrus; 7 - projection zone of the olfactory analyzer (simplified diagram).

in the perialmond-shaped and subcallosal areas, in the nuclei of the transparent septum, located anterior to the anterior commissure. The anterior commissure connects both olfactory regions and also provides their connection to the limbic system of the brain. Part of the axons of the third neurons of the olfactory analyzer, passing through the anterior commissure of the brain, crosses.

Axons of third neurons olfactory analyzer, located in the subcortical olfactory centers, heading towards phylogenetically old crust mediobasal surface of the temporal lobe (to the piriform and parahippocampal gyrus and to the hook), where the projection olfactory zone is located, or the cortical end of the olfactory analyzer (field 28, according to Brodmann).

The olfactory system is thus the only sensory system in which specific impulses bypass the thalamus on their way from the receptors to the cortex. However, The olfactory system has especially pronounced connections with the limbic structures of the brain, and the information received through it has a significant impact on the state of the emotional sphere and the functions of the autonomic nervous system. Smells can be pleasant and unpleasant, they affect appetite, mood, can cause a variety of vegetative reactions, in particular nausea, vomiting.

14.4.2. Investigation of the sense of smell and the significance of its disorders for topical diagnostics

When examining the state of smell, it is necessary to find out whether the patient smells, whether these sensations are the same on both sides, whether the patient differentiates the nature of the smells felt, whether he has olfactory hallucinations - paroxysmal sensations of smell that are absent in the environment.

To study the sense of smell, odorous substances are used, the smell of which is not sharp (pungent odors can cause irritation of the trigeminal nerve receptors located in the nasal mucosa) and is known to the patient (otherwise it is difficult to recognize the perversion of smell). The sense of smell is checked on each side separately, while the other nostril must be closed. You can use specially prepared sets of weak solutions of odorous substances (mint, tar, camphor, etc.), in practical work, improvised means (rye bread, soap, banana, etc.) can also be used.

Decreased sense of smell - hyposmia, lack of smell - anosmia, heightened sense of smell hyperosmia, perversion of odors dysosmia, sensation of smell in the absence of a stimulus - parosmia, subjective sensation of an unpleasant odor that actually exists and is caused by organic pathology in the nasopharynx - kakosmiya, smells that do not really exist, which the patient feels paroxysmally - olfactory hallucinations - are more often the olfactory aura of temporal lobe epilepsy, which can be due to various reasons, in particular, a tumor of the temporal lobe.

Hyposmia or anosmia on both sides is usually the result of damage to the nasal mucosa due to acute catarrh, influenza, allergic rhinitis, atrophy of the mucous membrane

nose due to chronic rhinitis and prolonged use of vasoconstrictor nasal drops. Chronic rhinitis with atrophy of the nasal mucosa (atrophic rhinitis), Sjögren's disease dooms a person to persistent anosmia. Bilateral hyposmia can be caused by hypothyroidism, diabetes mellitus, hypogonadism, renal failure, prolonged contact with heavy metals, formaldehyde, etc.

However, unilateral hyposmia or anosmia is often the result of an intracranial tumor, more often meningioma of the anterior cranial (olfactory) fossa, which accounts for up to 10% of intracranial meningiomas, as well as some glial tumors of the frontal lobe. Olfactory disorders occur as a result of compression of the olfactory tract on the side of the pathological focus and may be the only focal symptom of the disease for a certain time. Tumors can be visualized by CT or MRI scanning. As the meningioma of the olfactory fossa increases, as a rule, mental disorders characteristic of the frontal syndrome develop (see Chapter 15).

Unilateral damage to the parts of the olfactory analyzer located above its subcortical centers, due to incomplete decussation of the pathways at the level of the anterior cerebral commissure, usually does not lead to a significant decrease in the sense of smell. Irritation by the pathological process of the cortex of the mediobasal parts of the temporal lobe, primarily the parahippocampal gyrus and its hook, can cause a paroxysmal occurrence olfactory hallucinations. The patient suddenly begins to smell for no reason, often of an unpleasant nature (the smell of burnt, rotten, rotten, burnt, etc.). Olfactory hallucinations in the presence of an epileptogenic focus in the mediobasal regions of the temporal lobe of the brain may be a manifestation of the aura of an epileptic seizure. The defeat of the proximal part, in particular the cortical end of the olfactory analyzer, can cause moderate bilateral (more on the opposite side) hyposmia and impaired ability to identify and differentiate odors (olfactory agnosia). The last form of olfactory disorder, which manifests itself in old age, is most likely associated with a violation of the function of the cortex due to atrophic processes in its projection olfactory zone.

14.5. LIMBIC-RETICULAR COMPLEX

In 1878 P. Broca(Broca P., 1824-1880) under the name "large marginal, or limbic, lobe" (from Latin limbus - edge) united the hippocampus and the cingulate gyrus, interconnected by means of the isthmus of the cingulate gyrus, located above the ridge of the corpus callosum.

In 1937 D. Papets(Papez J.), on the basis of experimental data, put forward a reasoned objection to the previously existing concept of the involvement of the mediobasal structures of the cerebral hemispheres mainly in the provision of smell. He suggested that the main part of the mediobasal parts of the cerebral hemisphere, then called the olfactory brain (rhinencephalon), to which the limbic lobe belongs, is the morphological basis of the nervous mechanism of affective behavior, and united them under the name"emotional circle" which included the hypothalamus,

anterior nuclei of the thalamus, cingulate gyrus, hippocampus and their connections. Since then, these structures have also been referred to by physiologists as around Papetz.

concept "visceral brain" suggested P.D. McLean (1949), thus denoting a complex anatomical and physiological association, which since 1952 has been called "limbic system". Later it turned out that the limbic system is involved in the performance of diverse functions, and now most of it, including the cingulate and hippocampal (parahippocampal) gyrus, is usually combined into the limbic region, which has numerous connections with the structures of the reticular formation, making up with it limbic-reticular complex, providing a wide range of physiological and psychological processes.

Currently to limbic lobe it is customary to attribute elements of the old cortex (archiocortex), covering the dentate gyrus and the hippocampal gyrus; ancient cortex (paleocortex) of the anterior hippocampus; as well as the middle, or intermediate, cortex (mesocortex) of the cingulate gyrus. Term "limbic system" includes components of the limbic lobe and related structures - entorhinal (occupying most of the parahippocampal gyrus) and septal regions, as well as the amygdala complex and mastoid body (Duus P., 1995).

Mastoid body connects the structures of this system with the midbrain and with the reticular formation. Impulses originating in the limbic system can be transmitted through the anterior nucleus of the thalamus to the cingulate gyrus and to the neocortex along pathways formed by associative fibers. Impulses originating in the hypothalamus can reach the orbitofrontal cortex and the medial dorsal nucleus of the thalamus.

Numerous direct and feedback connections ensure the interconnection and interdependence of limbic structures and many formations of the diencephalon and oral parts of the brainstem (nonspecific nuclei of the thalamus, hypothalamus, putamen, frenulum, reticular formation of the brainstem), as well as with subcortical nuclei (globe pallidus, putamen, caudate nucleus ) and with the neocortex of the cerebral hemispheres, primarily with the cortex of the temporal and frontal lobes.

Despite phylogenetic, morphological, and cytoarchitectonic differences, many of the mentioned structures (limbic region, central and medial structures of the thalamus, hypothalamus, reticular formation of the trunk) are usually included in the so-called limbic-reticular complex, which acts as a zone of integration of many functions, providing the organization of polymodal, holistic reactions of the body to various influences, which is especially pronounced in stressful situations.

The structures of the limbic-reticular complex have a large number of inputs and outputs through which vicious circles of numerous afferent and efferent connections pass, ensuring the combined functioning of the formations included in this complex. and their interaction with all parts of the brain, including the cerebral cortex.

In the structures of the limbic-reticular complex, there is a convergence of sensitive impulses that occur in intero- and exteroreceptors, including the receptor fields of the sense organs. On this basis, in the limbic-reticular complex, primary synthesis of information about the state of the internal environment of the body, as well as about the factors of the external environment affecting the body, and elementary needs, biological motivations and accompanying emotions are formed.

The limbic-reticular complex determines the state of the emotional sphere, participates in the regulation of vegetative-visceral relationships aimed at maintaining the relative constancy of the internal environment (homeostasis), as well as energy supply and correlation of motor acts. The level of consciousness, the possibility of automated movements, the activity of motor and mental functions, speech, attention, the ability to orientate, memory, the change of wakefulness and sleep depend on its state.

Damage to the structures of the limbic-reticular complex can be accompanied by a variety of clinical symptoms: pronounced changes in the emotional sphere of a permanent and paroxysmal nature, anorexia or bulimia, sexual disorders, memory impairment, in particular signs of Korsakoff's syndrome, in which the patient loses the ability to remember current events (retains current events in memory for no more than 2 minutes), autonomic-endocrine disorders, sleep disorders, psychosensory disorders in the form of illusions and hallucinations, changes in consciousness, clinical manifestations of akinetic mutism, epileptic seizures.

To date, a large number of studies have been conducted on the study of morphology, anatomical relationships, the function of the limbic region and other structures included in the limbic-reticular complex, however, the physiology and features of the clinical picture of its lesion today still largely need to be clarified. Most of the information about its function, especially the functions of the parahippocampal region, obtained in animal experiments methods of irritation, extirpation or stereotaxis. Obtained in this way results require caution when extrapolating to humans. Of particular importance are clinical observations of patients with lesions of the mediobasal parts of the cerebral hemisphere.

In the 50-60s of the XX century. in the period of development of psychosurgery, there were reports of the treatment of patients with incurable mental disorders and chronic pain syndrome by bilateral cingulotomy (dissection of the cingulate gyrus), while regression of anxiety, obsessional states, psychomotor agitation, pain syndromes was usually noted, which was recognized as evidence of the participation of the cingulate gyrus in the formation emotions and pain. At the same time, bicingulotomy led to profound personality disorders, to disorientation, a decrease in the criticality of one's condition, and euphoria.

An analysis of 80 verified clinical cases of hippocampal lesions on the basis of the Neurosurgical Institute of the Russian Academy of Medical Sciences is given in the monograph by N.N. Bragina (1974). The author comes to the conclusion that temporal mediobasal syndrome includes viscerovegetative, motor and mental disorders, usually manifested in a complex. All the variety of clinical manifestations of N.N. Bragin reduces to two main multifactorial variants of pathology with a predominance of "irritative" and "inhibitory" phenomena.

The first of these includes emotional disorders accompanied by motor anxiety (increased excitability, verbosity, fussiness, a feeling of internal anxiety), paroxysms of fear, vital anguish, various viscerovegetative disorders (changes in pulse, respiration, gastrointestinal disorders, fever, increased sweating and etc.). In these patients, against the background of constant motor restlessness, attacks of motor excitation often occurred.

niya. The EEG of this group of patients was characterized by mild cerebral changes towards integration (accelerated and pointed alpha rhythm, diffuse beta oscillations). In this case, repeated afferent stimuli evoked clear EEG responses, which, unlike normal ones, did not fade away as the stimuli were repeatedly presented.

The second (“inhibitory”) variant of the mediobasal syndrome is characterized by emotional disturbances in the form of depression with motor retardation (depressed mood background, depletion and slowing of the pace of mental processes, changes in motor skills, resembling the akinetic-rigid syndrome type. Viscerovegetative paroxysms noted in the first group are less characteristic. The EEG of patients in this group was characterized by cerebral changes, manifested in the predominance of slow forms of activity (irregular, delayed alpha rhythm, groups of theta oscillations, diffuse delta waves).A sharp decrease in EEG reactivity attracted attention.

Between these two extreme variants there were also intermediate ones with transitional and mixed combinations of individual symptoms. So, some of them are characterized by relatively weak signs of agitated depression with increased motor activity and fatigue, with a predominance of senestopathic sensations, suspicion, which in some patients reaches paranoid states, and hypochondriacal delirium. The other intermediate group was distinguished by the extreme intensity of depressive symptoms against the background of the patient's stiffness.

These data allow us to speak about the dual (activating and inhibitory) influence of the hippocampus and other structures of the limbic region on behavioral reactions, emotions, mental status, and bioelectrical activity of the cortex. Currently, complex clinical syndromes of this type should not be regarded as primary focal. Rather, they should be considered in the light of ideas about a multilevel system of organization of brain activity.

S.B. Buklina (1997) cited data from a survey of 41 patients with arteriovenous malformations in the area of ​​the cingulate gyrus. Before surgery, 38 patients had memory disorders in the forefront, and five of them had signs of Korsakoff's syndrome, in three patients Korsakoff's syndrome arose after surgery, while the severity of the increase in memory defects correlated with the degree of destruction of the cingulate gyrus itself, as well as with involvement in pathological process of the adjacent structures of the corpus callosum, while the amnesic syndrome did not depend on the side of the malformation location and its localization along the length of the cingulate gyrus.

The main characteristics of the identified amnestic syndromes were disorders in the reproduction of auditory-speech stimuli, violations of the selectivity of traces in the form of inclusions and contaminations, and inability to retain meaning in the transmission of a story. In most patients, the criticality of assessing their condition was reduced. The author noted the similarity of these disorders with amnestic defects in patients with frontal lesions, which can be explained by the presence of connections between the cingulate gyrus and the frontal lobe.

More widespread pathological processes in the limbic region cause pronounced disorders of the vegetative-visceral functions.

corpus callosum(corpus callosum)- the largest commissure between the cerebral hemispheres. Its anterior sections, in particular the knee of the corpus callosum

body (genu corporis callosi), connect the frontal lobes, the middle sections - the trunk of the corpus callosum (truncus corporis callosi)- provide communication between the temporal and parietal sections of the hemispheres, the posterior sections, in particular the corpus callosum ridge (splenium corporis callosi), connect the occipital lobes.

Lesions of the corpus callosum are usually accompanied by disorders of the mental state of the patient. The destruction of its anterior section leads to the development of the “frontal psyche” (aspontaneity, violations of the action plan, behavior, criticism, characteristic of frontal callous syndrome - akinesia, amimia, aspontaneity, astasia-abasia, apraxia, grasp reflexes, dementia). Disconnection of connections between the parietal lobes leads to perversion understanding "body plans" and appearance of apraxia mostly in the left hand. Dissociation of the temporal lobes may manifest violation of the perception of the external environment, the loss of the correct orientation in it (amnestic disorders, confabulations, the syndrome of what has already been seen etc.). Pathological foci in the posterior parts of the corpus callosum are often characterized by signs of visual agnosia.

14.6. ARCHITECTONICS OF THE BRAIN CORTEX

The structure of the cerebral cortex is heterogeneous. Less complex in structure, early emerging in the process of phylogenesis ancient bark (archiocortex) and old bark (paleocortex), related mostly to limbic lobe brain. The greater part of the cerebral cortex (95.6%), due to its later phylogenetic formation, is called new bark (neocortex) and has a much more complex multilayer structure, but also heterogeneous in its various zones.

Due to the fact that the architectonics of the cortex is in a certain connection with its function, much attention has been devoted to its study. One of the founders of the doctrine of the cytoarchitectonics of the cortex was V.A. Betz (1834-1894), who for the first time in 1874 described the large pyramidal cells of the motor cortex (Betz cells) and determined the principles for dividing the cerebral cortex into main areas. In the future, a great contribution to the development of the theory of the structure of the cortex was made by many researchers - A. Campbell (A. Cambell), E. Smith (E. Smith), K. Brodmann (K. Brodmann), Oscar Vogt and Cecilia Vogt (O. Vogt , S. Vogt). Great merit in the study of the architectonics of the cortex belongs to the staff of the Institute of the Brain of the Academy of Medical Sciences (S.A. Sarkisov, N.I. Filimonov, E.P. Kononova, etc.).

The main type of structure of the new crust (Fig. 14.5), with which all its sections are compared - a cortex consisting of 6 layers (homotypic cortex, according to Brodman).

Layer I - molecular, or zonal, the most superficial, poor in cells, its fibers have a direction, mainly parallel to the surface of the cortex.

II layer - outer granular. Consists of a large number of densely arranged small granular nerve cells.

III layer - small and medium pyramids, the widest. It consists of pyramidal cells, the sizes of which are not the same, which allows dividing this layer into sublayers in most cortical fields.

IV layer - internal granular. It consists of densely arranged small cells-grains of a round and angular shape. This layer is the most variable

Rice. 14.5.Cytoarchitectonics and myeloarchitectonics of the motor zone of the cerebral cortex.

Left: I - molecular layer; II - outer granular layer; III - layer of small and medium pyramids; IV - inner granular layer; V - layer of large pyramids; VI - layer of polymorphic cells; on the right - elements of myeloarchitectonics.

in some fields (for example, field 17), it is divided into sublayers, in some places it sharply becomes thinner and even completely disappears.

V layer - large pyramids, or ganglionic. Contains large pyramidal cells. In some areas of the brain, the layer is divided into sublayers, in the motor zone it consists of three sublayers, the middle of which contains Betz's giant pyramidal cells, reaching 120 microns in diameter.

VI layer - polymorphic cells, or multiform. Consists mainly of triangular spindle-shaped cells.

The structure of the cerebral cortex has a large number of variations due to changes in the thickness of individual layers, thinning or disappearance or,

on the contrary, thickening and division into sublayers of some of them (heterotypic zones, according to Brodman).

The cortex of each cerebral hemisphere is divided into several regions: occipital, superior and inferior parietal, postcentral, central gyri, precentral, frontal, temporal, limbic, insular. Each of them in accordance with the characteristics subdivided into a number of fields, moreover, each field has its own conventional ordinal designation (Fig. 14.6).

The study of the architectonics of the cerebral cortex, along with physiological, including electrophysiological, studies and clinical observations, contributed in many respects to the solution of the problem of the distribution of functions in the cortex.

14.7. PROJECTION AND ASSOCIATION FIELDS OF THE CORTUS

In the process of developing the doctrine of the role of the cerebral cortex and its individual sections in the performance of certain functions, there were different, sometimes opposite, points of view. Thus, there was an opinion about a strictly local representation in the cerebral cortex of all human abilities and functions, up to the most complex, mental (localizationism, psychomorphology). He was opposed by another opinion about the absolute functional equivalence of all parts of the cerebral cortex (equipotentialism).

An important contribution to the theory of localization of functions in the cerebral cortex was made by I.P. Pavlov (1848-1936). He singled out the projection zones of the cortex (the cortical ends of the analyzers of certain types of sensitivity) and the associative zones located between them, studied the processes of inhibition and excitation in the brain, and their influence on the functional state of the cerebral cortex. The division of the cortex into projection and associative zones contributes to understanding the organization of the work of the cerebral cortex and justifies itself in solving practical problems, in particular, in topical diagnostics.

projection zones provide mainly simple specific physiological acts, primarily the perception of sensations of a certain modality. The projection pathways approaching them connect these zones with the receptor territories on the periphery that are in functional correspondence with them. Examples of projection cortical zones are the region of the posterior central gyrus already described in previous chapters (the zone of general types of sensitivity) or the region of the spur groove located on the medial side of the occipital lobe (the projection visual zone).

Association zones the cortex does not have direct connections with the periphery. They are located between the projection zones and have numerous associative links with these projection zones and with other associative zones. The function of the associative zones is to carry out a higher analysis and synthesis of many elementary and more complex components. Here, in essence, there is an understanding of the information entering the brain, the formation of ideas and concepts.

G.I. Polyakov in 1969, based on a comparison of the architectonics of the human cerebral cortex and some animals, found that associative

Rice. 14.6.Architectonic fields of the cerebral cortex [according to Brodman]. a - outer surface; b - medial surface.

zones in the human cerebral cortex are 50%, in the cortex of higher (humanoid) monkeys - 20%, in lower monkeys this figure is 10% (Fig. 14.7). Among the association areas of the cortex of the human brain, the same author suggested isolating secondary and tertiary fields. Secondary associative fields are adjacent to the projection ones. They carry out the analysis and synthesis of elementary sensations that still retains a specific orientation.

Tertiary associative fields are located mainly between the secondary ones and are overlapping zones of neighboring territories. They are related primarily to the analytical activity of the cortex, providing the highest mental functions that are characteristic of a person in their most complex intellectual and speech manifestations. Functional maturity of tertiary as-

Rice. 14.7. Differentiation of projection and associative areas of the cerebral cortex during the evolution of primates [according to G.I. Polyakov]. a - the brain of the lower monkey; b - the brain of a higher ape; c - the human brain. Large dots indicate projection zones, small dots - associative ones. In lower monkeys, associative zones occupy 10% of the area of ​​the cortex, in higher ones - 20%, in humans - 50%.

social fields of the cerebral cortex occurs most late and only in a favorable social environment. Unlike other cortical fields, the tertiary fields of the right and left hemispheres are characterized by a pronounced functional asymmetry.

14.8. TOPICAL DIAGNOSIS OF LESIONS OF THE BRAIN CORTEX

14.8.1. Manifestations of damage to the projection zones of the cerebral cortex

In the cortex of each cerebral hemisphere, behind the central gyrus, there are 6 projection zones.

1. In the anterior part of the parietal lobe, in the region of the posterior central gyrus (cytoarchitectonic fields 1, 2, 3) located projection zone of general types of sensitivity(Fig. 14.4). The areas of the cortex located here receive sensitive impulses coming along the projection pathways of general types of sensitivity from the receptor apparatus of the opposite half of the body. The higher the area of ​​this projection zone of the cortex is, the lower the located parts of the opposite half of the body it has projection connections. Parts of the body with extensive reception (tongue, palmar surface of the hand) correspond to inadequately large parts of the area of ​​projection zones, while other parts of the body (proximal limbs, torso) have a small area of ​​cortical representation.

Irritation by the pathological process of the cortical zone of general types of sensitivity leads to an attack of paresthesia in parts of the body corresponding to the irritated areas of the cerebral cortex (sensitive Jacksonian seizure), which can turn into a secondary generalized paroxysm. The defeat of the cortical end of the analyzer of general types of sensitivity can cause the development of hypalgesia or anesthesia in the corresponding zone of the opposite half of the body, while the site of hypesthesia or anesthesia can be of a vertical circulatory or radicular-segmental type. In the first case, the sensitivity disorder manifests itself on the side opposite to the pathological focus in the region of the lips, thumb or in the distal part of the limb with a circular border, sometimes like a sock or glove. In the second case, the zone of sensitivity disturbance has the form of a strip and is located along the inner or outer edge of the arm or leg; this is explained by the fact that the inner side of the limbs is presented in the anterior, and the outer side - in the posterior sections of the projection zone of the analyzer of general types of sensitivity.

2. Visual projection zone located in the cortex of the medial surface of the occipital lobe in the region of the spur groove (field 17). In this field, there is a stratification of the IV (inner granular) layer of the cortex with a bundle of myelin fibers into two sublayers. Separate sections of field 17 receive impulses from certain sections of the homonymous halves of the retinas of both eyes; while the impulses coming from the lower parts of the homonymous halves of the retinas reach

the cortex of the lower lip of the spur groove, and the impulses coming from the upper parts of the retinas are directed to the cortex of its upper lip.

The defeat of the pathological process of the visual projection zone leads to the appearance on the opposite side of the quadrant or complete homonymous hemianopia on the side opposite to the pathological focus. Bilateral damage to the cortical fields 17 or the projection visual pathways leading to them can lead to complete blindness. Irritation of the cortex of the visual projection zone can cause the appearance of visual hallucinations in the form of photopsies in the corresponding parts of the opposite halves of the visual fields.

3. Hearing projection area located in the cortex of the convolutions of Heschl on the lower lip of the lateral (Sylvian) furrow (fields 41 and 42), which are, in fact, part of the superior temporal gyrus. Irritation of this zone of the cortex can cause the occurrence of auditory hallucinations (attacks of feeling noise, ringing, whistling, buzzing, etc.). The destruction of the auditory projection zone on the one hand can cause some hearing loss in both ears, to a greater extent on the opposite with respect to the pathological focus.

4 and 5. Olfactory and gustatory projection zones are on the medial surface of the vaulted gyrus (limbic region) of the brain. The first of them is located in the parahippocampal gyrus (field 28). The projection zone of taste is usually localized in the cortex of the opercular area (field 43). Irritation of the projection zones of smell and taste can cause their perversion or lead to the development of the corresponding olfactory and gustatory hallucinations. Unilateral loss of the function of the projection zones of smell and taste can cause a slight decrease in smell and taste, respectively, on both sides. Bilateral destruction of the cortical ends of the same analyzers is manifested by the absence of smell and taste on both sides, respectively.

6. Vestibular projection zone. Its localization is not specified. At the same time, it is known that the vestibular apparatus has numerous anatomical and functional connections. It is possible that the localization of the representation of the vestibular system in the cortex has not yet been clarified because it is polyfocal. N.S. Blagoveshchenskaya (1981) believes that in the cerebral cortex the vestibular projection zones are represented by several anatomical and functional interacting complexes, which are located in field 8, at the junction of the frontal, temporal and parietal lobes and in the zone of the central gyri, while it is assumed that each of these areas of the cortex performs its own functions. Field 8 is an arbitrary center of the gaze, its irritation causes the gaze to turn in the direction opposite to the pathological focus, changes in the rhythm and nature of the experimental nystagmus, especially soon after an epileptic seizure. In the cortex of the temporal lobe there are structures, the irritation of which causes dizziness, which manifests itself, in particular, in temporal lobe epilepsy; the defeat of the areas of representation of the vestibular structures in the cortex of the central gyri affects the state of the tone of the striated muscles. Clinical observations suggest that the nuclear-cortical vestibular pathways make a partial decussation.

It should be emphasized that signs of irritation of the listed projection zones can be a manifestation of the aura of an epileptic seizure corresponding in nature.

I.P. Pavlov considered it possible to consider the cortex of the precentral gyrus, which affects the motor functions and muscle tone of the predominantly opposite half of the body, with which it is connected primarily by the cortical-nuclear and cortical-spinal (pyramidal) pathways, as the projection zone of the so-called motor analyzer. This zone occupies first of all, field 4, on which the opposite half of the body is projected in an inverted form. This field contains the bulk of giant pyramidal cells (Betz cells), the axons of which make up 2-2.5% of all fibers of the pyramidal pathway, as well as medium and small pyramidal cells, which, together with the axons of the same cells located in the adjacent to the field 4 more extensive field 6, are involved in the implementation of monosynaptic and polysynaptic cortical-muscular connections. Monosynaptic connections provide mainly fast and precise targeted actions, depending on the contractions of individual striated muscles.

Damage to the lower parts of the motor zone usually leads to development on the opposite side brachiofacial (shoulder facial) syndrome or linguofaciobrachial syndrome, which are often observed in patients with cerebrovascular accident in the basin of the middle cerebral artery, with combined paresis of the muscles of the face, tongue and arm, especially the shoulder in the central type.

Irritation of the cortex of the motor zone (fields 4 and 6) leads to the appearance of convulsions in the muscles or muscle groups projected onto this zone. More often, these are local convulsions of the type of Jacksonian epilepsy, which can transform into a secondary generalized epileptic seizure.

14.8.2. Manifestations of damage to the associative fields of the cerebral cortex

Between the projection zones of the cortex are association fields. They receive impulses mainly from the cells of the projection zones of the cortex. In the associative fields, the analysis and synthesis of information that has undergone primary processing in the projection fields takes place. The associative zones of the cortex of the superior parietal lobule provide a synthesis of elementary sensations, in connection with this, such complex types of sensitivity as a sense of localization, a sense of weight, a two-dimensional sense, as well as complex kinesthetic sensations are formed here.

In the region of the interparietal sulcus, there is an associative zone that provides a synthesis of sensations emanating from parts of one's own body. Damage to this region of the cortex leads to autopagnosia, those. to not recognizing or ignoring parts of one's own body, or to pseudomelia the feeling of having an extra arm or leg, and anosognosia - lack of awareness of a physical defect that has arisen in connection with the disease (for example, paralysis or paresis of a limb). Usually, all types of autopagnosia and anosognosia occur when the pathological process is located on the right.

The defeat of the lower parietal lobule can be manifested by a disorder in the synthesis of elementary sensations or the inability to compare the synthesized complex sensations with "there was once in the perception of similar

in the same way, on the basis of the results of which recognition occurs ”(V.M. Bekhterev). This is manifested by a violation of the two-dimensional spatial sense (grafoesthesia) and three-dimensional spatial sense (stereognosis) - astereognosis.

In the case of damage to the premotor zones of the frontal lobe (fields 6, 8, 44), frontal ataxia usually occurs, in which the synthesis of afferent impulses (kinesthetic afferentation) is disturbed, signaling the position of body parts in space changing in the process of movements.

In case of violation of the function of the cortex of the anterior parts of the frontal lobe, which has connections with the opposite hemisphere of the cerebellum (fronto-bridge-cerebellar connections), statokinetic disturbances occur on the opposite side of the pathological focus (frontal ataxia). Particularly distinct are violations of late developing forms of statokinetics - upright standing and upright walking. As a result, the patient has uncertainty, unsteadiness of gait. While walking, his body leans back. (Henner sign) he puts his feet in a straight line (fox walk) sometimes when walking there is a "braiding" of the legs. In some patients with damage to the anterior parts of the frontal lobes, a peculiar phenomenon develops: in the absence of paralysis and paresis and the preserved ability to move the legs in full, patients cannot stand (astasia) and walk (abasia).

The defeat of the associative zones of the cortex is often characterized by the development of clinical manifestations of a violation of higher mental functions (see Chapter 15).

All the possibilities of a living being are inextricably linked with the brain. Studying the anatomy of this unique organ, scientists never cease to be amazed at its capabilities.

In many ways, the set of functions is associated with the structure, the understanding of which allows you to correctly diagnose and treat a number of diseases. Therefore, examining the furrows and convolutions of the brain, experts try to note the features of their structure, deviations from which will become a sign of pathology.

What's this?

The topography of the contents of the cranium showed that the surface of the organ responsible for the functioning of the human body is a series of elevations and depressions, which become more pronounced with age. So the area of ​​the brain expands while maintaining volume.

Convolutions are called folds that characterize an organ in the final stage of development. Scientists associate their formation with different indicators of tension in the brain regions in childhood.

Furrows are called channels that separate the gyrus. They divide the hemispheres into main sections. According to the time of formation, there are primary, secondary and tertiary types. One of them is formed during the prenatal period of human development.

Others are acquired at a more mature age, remaining unchanged. The tertiary furrows of the brain have the ability to transform. Differences may relate to shape, direction and size.

Structure

When determining the main elements of the brain, it is better to use a diagram in order to more clearly understand the overall picture. The primary recesses of the cortex include the main grooves, dividing the organ into two large parts, called hemispheres, and also delimiting the main sections:

• between the temporal and frontal lobes is the Sylvius furrow;
• Roland's depression is located on the border between the parietal and frontal parts;
• The parietal-occipital cavity is formed at the junction of the occipital and parietal zones;
• along the Belt cavity, passing into the hippocampal one, they find the olfactory brain.

The formation of relief always occurs in a certain order. Primary furrows appear starting from the tenth week of pregnancy. First, the lateral is formed, followed by the central and others.

In addition to the main grooves, which have distinctive names, a certain number of secondary depressions appear between 24-38 weeks of the prenatal period. Their development continues after the birth of the child. Along the way, tertiary formations are formed, the number of which is purely individual. Personal characteristics and the intellectual level of an adult are among the factors that affect the relief of an organ.

Formation and functions of the convolutions of the brain

It was revealed that the main sections of the contents of the cranium begin to form from the mother's womb. And each of them is responsible for a separate side of the human personality. Thus, the function of the temporal gyri is associated with the perception of written and oral speech.

Here is the center of Wernicke, the damage of which leads to the fact that a person ceases to understand what is being said to him. At the same time, it is preserved to pronounce and write down words. The disease is called sensory aphasia.

In the region of the inferior pubic gyrus, there is a formation responsible for the reproduction of words, which is called Broca's speech center. If MRI reveals damage to this brain region, motor aphasia is observed on the part of the patient. This means a complete understanding of what is happening, but the inability to express your thoughts and feelings in words.

This happens when there is a violation of the blood supply in the cerebral artery.

Damage to all departments responsible for speech can cause complete aphasia, in which a person can lose touch with the outside world due to the inability to communicate with others.

The anterior central gyrus is functionally different from the others. Being part of the pyramidal system, it is responsible for the execution of conscious movements. The functioning of the posterior central eminence is inextricably linked to the human senses. Thanks to her work, people feel heat, cold, pain or touch.

The angular gyrus is located in the parietal lobe of the brain. Its significance is related to the visual recognition of the resulting images. It also undergoes processes that allow you to decipher sounds. The cingulate gyrus above the corpus callosum is a component of the limbic system.

It is responsible for emotions and control of aggressive behavior.

Memory plays an important role in human life. It plays an important role in its own education and education of new generations. And the preservation of memories would be impossible without the hippocampal gyrus.

Doctors studying neuropathology note that the defeat of one of the brain regions is more common than the disease of the entire organ. In the latter case, the patient is diagnosed with atrophy, in which a large number of irregularities are smoothed out. This disease is closely associated with serious intellectual, psychological and mental disabilities.

Lobes of the brain and their functions

Thanks to the furrows and convolutions, the organ inside the cranium is divided into several zones that are different in purpose. So, the frontal part of the brain, which is located in the anterior cortex, is associated with the ability to express and regulate emotions, make plans, reason and solve problems.

The degree of its development determines the intellectual and mental level of a person.

The parietal lobe is responsible for sensory information. It also allows you to separate contacts produced by multiple objects. The temporal region contains everything necessary to process the received visual and auditory information. The medial zone is associated with learning, perception of emotions and memory.

The midbrain allows you to maintain muscle tone, response to sound and visual stimuli. The back of the organ is divided into the oblong part, the bridge and the cerebellum. The dorsolateral lobe is responsible for regulating respiration, digestion, chewing, swallowing, and defense reflexes.