Finite brain. Fissures and convolutions Posterior central gyrus of the brain

The surface of the cerebral cortex consists of folds - convolutions. They are separated by grooves; the shallow ones are called cerebral sulci, the deep ones are called cerebral fissures.

The main surface of the cloak lobes consists of grooves and convolutions. The grooves (sulci) are deep folds of the mantle containing stratified bodies of neurons - the cortex (gray matter of the mantle) and cell processes (white matter of the mantle). Between these grooves there are rollers of the cloak, which are usually called convolutions (gyri). They contain the same components as the grooves. Each section has its own permanent grooves and convolutions.

The grooves of the telencephalon are divided into three main categories, which reflect their depth, occurrence and stability of outline.

Constant (main) grooves (first order grooves). A person has 10 of them. These are the deepest folds on the surface of the brain, which change least among different people. First order furrows appear during early development and are characteristic of each animal species and humans.

Non-permanent grooves (furrows of the second order). These folds, located on the surface of the telencephalon hemispheres, have a characteristic location and direction in which they are oriented. These grooves can individually vary within very wide limits or even be absent. The depth of these grooves is quite large, but significantly less than that of the first-order grooves.

Non-permanent grooves (third order grooves) are called sulci. They rarely reach significant sizes, their outlines are variable, and their topology has ethnic or individual characteristics. As a rule, third-order furrows are not inherited.

The shape of the grooves and convolutions has great individual variability and is a visual criterion (comparable to a fingerprint pattern) that distinguishes one person from another.

Cerebral cortex or cortex (lat. cortex cerebri) - structure brain, layer gray matter 1.3-4.5 mm thick, located along the periphery cerebral hemispheres, and covering them. The larger primary sulci of the hemisphere should be distinguished:

1) the central (Rolandic) sulcus (sulcus centralis), which separates the frontal lobe from the parietal lobe;

2) the lateral (Sylvian) fissure (sulcus lateralis), which separates the frontal and parietal lobes from the temporal lobe;

3) parieto-occipital groove (sulcus parietooccipitalis), separating the parietal lobe from the occipital lobe.

Approximately parallel to the central sulcus is the precentral sulcus, which does not reach the upper edge of the hemisphere. The precentral sulcus borders the precentral gyrus in front.

Superior and inferior frontal sulcus are directed from the precentral sulcus forward. They divide the frontal lobe into:

superior frontal gyrus, which is located above the superior frontal sulcus and passes to the medial surface of the hemisphere

the middle frontal gyrus, which is bounded by the superior and inferior frontal sulci. The orbital (anterior) segment of this gyrus passes onto the inferior surface of the frontal lobe

The inferior frontal gyrus, which lies between the inferior frontal sulcus and the lateral sulcus of the brain and the branches of the lateral sulcus, is divided into a number of parts:

1. posterior - tegmental part (lat. pars opercularis), limited in front by the ascending branch

   middle - triangular part (lat. pars triangularis), lying between the ascending and anterior branches

   anterior - orbital part (lat. pars orbitalis), located between the anterior branch and the inferolateral edge of the frontal lobe

The postcentral gyrus runs parallel to the precentral gyrus. From it posteriorly, almost parallel to the longitudinal fissure of the cerebrum, there is an intraparietal groove, dividing the posterosuperior sections of the parietal sections of the parietal lobe into two gyri: the superior and inferior parietal lobes.

In the inferior parietal lobule There are two relatively small convolutions: supramarginal, lying anteriorly and closing the posterior sections of the lateral groove, and located posterior to the previous one corner, which closes the superior temporal sulcus.

Between the ascending and posterior branches of the lateral sulcus of the brain there is a section of the cortex designated as frontoparietal operculum. It includes the posterior part of the inferior frontal gyrus, the lower parts of the precentral and postcentral gyri, as well as the lower part of the anterior part of the parietal lobe.

Top and bottom temporal sulci, located on the superolateral, divide the lobe into three temporal gyri: top, middle and bottom.

Those parts of the temporal lobe that are directed towards the lateral sulcus of the brain are cut by short transverse temporal sulci. Between these grooves lie 2-3 short transverse temporal gyri, connected with the gyri of the temporal lobe and the insula.

Insula (islet)

A large number of small convolutions of the island are visible on the surface. The large anterior part consists of several short convolutions of the insula, the posterior part consists of one long convolution

№6 Cerebellum its connections and functions

The cerebellum (Latin cerebellum - literally “small brain”) is a section of the vertebrate brain responsible for coordination of movements, regulation of balance and muscle tone. In humans, it is located behind the medulla oblongata and the pons, under the occipital lobes of the cerebral hemispheres.

Contacts: The cerebellum has three pairs of peduncles: inferior, middle and superior. The lower leg connects it with the medulla oblongata, the middle one with the pons, and the upper one with the midbrain. The cerebral peduncles make up the pathways that carry impulses to and from the cerebellum.

Functions: The cerebellar vermis ensures stabilization of the center of gravity of the body, its balance, stability, regulation of the tone of reciprocal muscle groups, mainly the neck and torso, and the emergence of physiological cerebellar synergies that stabilize the balance of the body. To successfully maintain body balance, the cerebellum constantly receives information passing through the spinocerebellar tracts from the proprioceptors of various parts of the body, as well as from the vestibular nuclei, inferior olives, reticular formation and other formations involved in controlling the position of body parts in space. Most of the afferent pathways going to the cerebellum pass through the inferior cerebellar peduncle, some of them are located in the superior cerebellar peduncle.

7. deep sensitivity, its types. Conducting pathways of deep sensitivity.Sensitivity - the ability of a living organism to perceive irritations emanating from the environment or from its own tissues and organs, and respond to them with differentiated forms of reactions.

Deep sensitivity. This name refers to the ability of deep tissues and organs (muscles, fascia, tendons, ligaments, bones, etc.) to perceive certain irritations and bring the corresponding centripetal impulse to the cerebral cortex. This includes: proprioceptive(perceives irritations that arise inside the body, in its deep tissues associated with the function of maintaining body position during movements) and interoceptive(perceives irritations from internal organs) sensitivity, as well as a feeling of pressure and vibration.

Conducting pathways of deep sensitivity.

The deep sensitivity pathways also unite three neurons: one peripheral and two central. They provide joint-muscular, vibration and partially tactile sensitivity.

The cells of peripheral, sensory neurons are embedded in the intervertebral spinal ganglia, their processes - the sensory fibers of the peripheral nerves - conduct impulses from the periphery from the sensory nerve endings. The central processes of these cells are long, go as part of the dorsal roots, without entering the dorsal horns, go to the posterior funiculi, rising to the lower parts of the medulla oblongata, and end in the sphenoid and thin nuclei. The sphenoid nucleus, located outside, is approached by bundles of the same name, which conduct deep sensitivity from the upper limbs and upper part of the body on their side. The thin core, located inside, is approached by bundles of the same name, which conduct deep sensitivity from the lower extremities and lower part of the body on their side.

The second neuron (central) starts from the nuclei of the medulla oblongata, in the interolive layer, crosses, moving to the opposite side, and ends in the external nuclei of the visual thalamus.

The third neuron (central) goes through the posterior leg of the internal capsule, approaches the postcentral gyrus and the superior parietal lobule.

The second and third neurons represent deep sensitivity of the opposite limbs and torso.

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 tentorium (subtentorial).

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 grooves (hence its other name pallium - cloak), sometimes penetrating to great depths into the substance of the brain.

Superolateral (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 inferior temporal lobe. The frontal and parietal lobes are separated central, or Rolandic, sulcus(sulcus centralis), which cuts through the upper edge of the hemisphere and is directed along its convexital surface down and forward, slightly short of the lateral sulcus. The parietal lobe is separated from the occipital lobe located behind it by the parieto-occipital and transverse occipital fissures running along the medial surface of the hemisphere.

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

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

On the convexital surface of the occipital lobe of the brain, the grooves 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 sulcus, which have a direction almost parallel to the lateral (Sylvian) fissure, 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 lower lip of the lateral (Sylvian) fissure. On its surface, facing the lateral sulcus, there are several small transverse grooves that highlight small transverse convolutions on it (Heschl's convolutions), which can be seen only by spreading the edges of the lateral groove.

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

Inner (medial) surface of the hemisphere. The central part of the inner surface of the hemisphere is closely connected with the structures of the diencephalon, from which it is separated by those related to the cerebrum vault (fornix) And corpus callosum (corpus callosum). The latter is bordered externally by a groove of the corpus callosum (sulcus corporis callosi), starting at the front part - the beak (rostrum) and ending at its thickened posterior end (splenium). Here the groove of the corpus callosum passes into the deep hippocampal groove (sulcus hippocampi), which penetrates deep into the substance of the hemisphere, pressing it into the cavity of the lower horn of the lateral ventricle, resulting in the formation of the so-called ammonium horn.

Slightly retreating from the sulcus of the corpus callosum and the hippocampal sulcus, the callosal-marginal, subparietal and nasal sulci are located, which are continuations of each other. These grooves delimit the outer arcuate part of the medial surface of the cerebral hemisphere, known as limbic lobe(lobus limbicus). There are two gyri in the limbic lobe. The upper part of the limbic lobe is the superior limbic (superior marginal), or encircling, gyrus (girus cinguli), the lower part is formed by the inferior limbic gyrus, or seahorse gyrus (girus hippocampi), or parahippocampal gyrus (girus parahyppocampalis), in front of which there is a hook (uncus).

Around the limbic lobe of the brain there are 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. Located on the border between the frontal and parietal lobes of the cerebral hemisphere paracentral lobule (lobulis paracentralis), which is a continuation of the anterior and posterior central gyri on the medial surface of the hemisphere. At the border between the parietal and occipital lobes, the parieto-occipital sulcus is clearly visible (sulcus parietooccipitalis). It extends back from the lower part of it calcarine groove (sulcus calcarinus). Between these deep grooves is a triangular-shaped gyrus known as the wedge. (cuneus). In front of the wedge there is a quadrangular gyrus related to the parietal lobe of the brain - the precuneus.

Lower surface of the hemisphere. 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 rectus gyrus (girus rectus). Externally it is delimited by the olfactory groove (sulcus olphactorius), to which the formations of the olfactory analyzer are adjacent below: the olfactory bulb and the olfactory tract. Lateral to it, up to the lateral (Sylvian) fissure, extending onto the lower surface of the frontal lobe, there are small orbital gyri (gyri orbitalis). The lateral parts 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 lower parts border on the inner side with the hippocampal gyrus, and the posterior ones - with the lingual (gyrus lingualis) or medial temporo-occipital gyrus (gyrus occipitotemporalis medialis). The latter with its posterior end is adjacent to the calcarine groove. The anterior sections of the fusiform and lingual gyri belong to the temporal lobe, and the posterior sections belong to the occipital lobe of the brain.

The cerebral hemispheres contain the centers of speech, memory, thinking, hearing, vision, musculoskeletal sensitivity, taste and smell, and movement. The activity of each organ is under the control of the cortex.

that the occipital region of the cortex is closely connected with the visual analyzer, the temporal region - with the auditory (Heschl's gyrus), taste analyzer, the anterior central gyrus - with the motor, the posterior central gyrus - with the musculocutaneous analyzer. We can conditionally assume that these departments are associated with the first type of cortical activity and provide the simplest forms of gnosis and praxis. Parts of the cortex located in the parietotemporal-occipital region take an active part in the formation of more complex gnostic-praxic functions. Damage to these areas leads to more complex forms of disorders. Wernicke's Gnostic speech center is located in the temporal lobe of the left hemisphere. The motor speech center is located somewhat anterior to the lower third of the anterior central gyrus (Broca's center). In addition to the centers of oral speech, there are sensory and motor centers of written speech and a number of other formations, one way or another related to speech. The parieto-temporo-occipital region, where the pathways coming from various analyzers are closed, is of utmost importance for the formation of higher mental functions. Scientists call this area the interpretive cortex. In this area there are also formations involved in memory mechanisms. Particular importance is also attached to the frontal region.

Logistics of the lesson

1. Corpse, skull.

2. Tables and models on the topic of the lesson

3. Set of general surgical instruments

Technological map for conducting a practical lesson.

Clinical situation

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

Tasks:

1. Explain at what level the fracture of the base of the skull occurred?

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

3. Prognostic value of liquorrhea.

The solution of the problem:

1. The fracture of the base of the skull is localized in the area of ​​the middle cranial fossa.

2. Bleeding from the ears is caused by damage to the pyramid of the temporal bone, tympanic membrane and middle cerebral artery. The “spectacles” symptom is caused by the spread of the hematoma through the superior orbital fissure into the orbital tissue.

3. Liquororrhea is a prognostically unfavorable symptom, indicating 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 leaves, between which there is a thin layer of loose fiber. Thanks to this, one layer of the membrane can be easily separated from the other and used to replace a defect in the dura mater (Burdenko’s method).

On the cranial vault, the dura mater is loosely connected to the bones and easily peels 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 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 connected to the bones very firmly, especially on the perforated plate of the ethmoid bone, in the circumference of the sella turcica, on the clivus, in the area of ​​the pyramids of the temporal bones.

Corresponding to the midline of the cranial vault or slightly to the right of it, the superior falx-shaped process of the dura mater (falx cerebri) is located, separating one cerebral hemisphere from the other (Fig. 2). It extends in the sagittal direction from the crista galli to the protuberantia occipitalis interna.

The lower free edge of the falx almost reaches the corpus callosum. In the posterior part, the falx connects with 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 semblance of a vault, and is attached posteriorly - on the occipital bone (along its transverse grooves), laterally - on the upper edge of the pyramid of both temporal bones, and in front - on the processus clinoidei of the sphenoid bone.

Rice. 1. Meninges of the brain, meninges encephali; frontal view:

1 – superior sagittal sinus, sinus sagittalis superior;

2 – scalp;

3 – dura mater cranialis (encephali);

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

5 – pia mater of the brain, pia mater cranialis (encephali);

6 – cerebral hemispheres, hemispherium cerebralis;

7 – falx cerebri, falx cerebri;

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

9 – skull bone (diploe);

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

11 – tendon helmet, galea aponeurotica;

12 – granulations of the arachnoid membrane, 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 part of the tentorium there is an oval-shaped opening - incisura tentorii (otherwise - the Pachyonic foramen), through which the stem part of the brain passes. With its upper surface, the tentorium cerebelli connects along the midline with the falx cerebelli, and from the lower surface of the cerebellar tent, also along the midline, a small falx cerebelli extends, penetrating into the groove between the cerebellar hemispheres.

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

2 – notch of the tentorium cerebellum, incisura tentorii;

3 – tentorium cerebellum, tentorium cerebelli;

4 – falx cerebellum, falx cerebelli;

5 – trigeminal cavity, cavitas trigeminalis;

6 – sella diaphragm, diaphragma sellae;

7 – tentorium cerebellum, tentorium cerebelli.

In the thickness of the processes of the dura mater there are venous sinuses devoid of valves (Fig. 3). The falciform process of the dura mater along its entire length contains the superior sagittal venous sinus (sinus sagittalis superior), which is adjacent to the bones of the cranial vault and, when injured, is often damaged and produces 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 falx contains the inferior sagittal sinus (sinus sagittalis inferior). Along the line of connection between the falx medullaris and the cerebellar tent there is a straight sinus (sinus rectus), into which the inferior sagittal sinus flows, as well as the great cerebral vein (Galena).

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

1 – falx cerebri, falx cerebri;

2 – inferior 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 – great cerebral (Galenian) vein, v.cerebri magna (Galeni);

8 – straight sinus, sinus rectus;

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

11 – marginal sinus, sinus marginalis;

12 – superior petrosal sinus, sinus petrosus superior;

13 – cavernous sinus, sinus cavernosus;

14 – petroparietal sinus, sinus sphenoparietalis;

15 – superior cerebral veins, vv.cerebrales superiores.

In the thickness of the falx of the cerebellum, along the line of its attachment to the internal occipital crest, the occipital sinus (sinus occipitalis) is contained.

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 sella turcica, the right and left sinuses are connected by anastomoses (intercavernous sinuses, sinusi intercavernosi), forming the annular sinus of Ridley - sinus circularis (Ridleyi) (BNA). The cavernous sinus collects blood from the small sinuses of the anterior part of the cranial cavity; in addition, which is especially important, the orbital veins (vv.ophthalmicae) flow into it, of which the upper one anastomoses with the v.angularis at the inner corner of the eye. Through emissaries, the cavernous sinus is directly connected to 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 – sphenoparietal sinus, sinus sphenoparietalis;

4 – cavernous sinus, sinus cavernosus;

5 – lower stony sinus, sinus petrosus inferior;

6 – superior petrosal 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 there are a. carotis interna and n.abducens, and in the thickness of the dura mater, which forms the outer wall of the sinus, pass (counting from top to bottom) the nerves - nn.oculomotorius, trochlearis and ophthalmicus. The semilunar ganglion of the trigeminal nerve is adjacent to the outer wall of the sinus, in its posterior section).

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 convexity upward and connects the external occipital tubercle with the superoposterior part of the mastoid process. The upper nuchal line approximately corresponds to this projection line.

The superior sagittal, rectus, occipital and both transverse sinuses in the area of ​​the internal occipital protuberance merge, this fusion is called confluens sinuum. The external projection of the fusion site 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 dura mater by a slit-like, so-called subdural, space. It is thin, does not contain vessels, and, unlike the pia mater, does not extend into the grooves delimiting the cerebral convolutions.

The arachnoid membrane forms special villi that pierce the dura mater and penetrate into the lumen of the venous sinuses or leave imprints on the bones - they are called granulations of the arachnoid membrane (otherwise known as Pachionian granulations).

Closest to the brain is the pia mater - pia mater encephali, rich in blood vessels; it enters all 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) it communicates with the central canal and subarachnoid space of the spinal cord. The fourth ventricle communicates with the third ventricle through the aqueduct of Sylvius.

In addition to the cerebrospinal fluid, the ventricles of the brain contain 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 inferior (in the temporal lobe). Through two interventricular foramina, the anterior horns of both lateral ventricles communicate with the third ventricle.

The slightly expanded sections of the subarachnoid space are called cisterns. They are located predominantly at the base of the brain, with the cisterna cerebellomedullaris having the greatest practical importance, delimited above by the cerebellum, in front by the medulla oblongata, below and behind by that part of the meninges that is adjacent to the membrana atlantooccipitalis. The cistern communicates with the IV ventricle through its middle opening (foramen Magandi), and below passes into the subarachnoid space of the spinal cord. A puncture of this cistern (suboccipinal puncture), which is often also called the cerebral cistern magna or the posterior cistern, is used to administer medications, reduce intracranial pressure (in some cases) and for diagnostic purposes.

The main sulci and convolutions of the brain

The central sulcus, sulcus centralis (Rolando), separates the frontal lobe from the parietal lobe. 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 lobe. If you separate the edges of the lateral fissure, a fossa (fossa lateralis cerebri) is revealed, at the bottom of which there is an island (insula).

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

The projections of the sulci of the brain onto the integument of the skull are determined according to the scheme of cranial 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 located parts 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 tracts in the medulla oblongata or spinal cord).

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

The blood supply to the brain is carried out by systems of four arteries - internal carotid and vertebral (Fig. 5). Both vertebral arteries at the base of the skull merge to form the basilar artery (a.basilaris), which runs in the groove on the lower surface of the medullary pons. 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 appears - 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 pons. At the base of the skull, the arterial circle surrounds the sella turcica and at the base of the brain – the papillary 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 the subcortical nodes.

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

The veins of the brain do not usually accompany the arteries. There are two systems of them: the system of superficial veins and the system of deep veins. The former are located on the surface of the cerebral convolutions, the latter - in the depths of the brain. Both of them flow into the venous sinuses of the dura mater, and the deep ones, merging, form the 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 quadrigeminal.

In the system of superficial veins there are two practically important anastomoses: one connects the sinus sagittalis superior with the sinus cavernosus (Trolard vein); the other usually connects the sinus transversus to the previous anastomosis (vein of Labbé).

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 cranial 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 craniocerebral (craniocerebral) topography proposed by Krenlein (Fig. 6). The same scheme makes it possible to project the most important grooves of the cerebral hemispheres onto the integument of the skull. The scheme is constructed as follows.

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

ас – lower horizontal; df – average horizontal; gi – upper horizontal; ag – front vertical; bh – middle vertical; сг – back vertical.

A lower horizontal line is drawn from the lower edge of the orbit along the zygomatic arch and the upper edge of the external auditory canal. An upper horizontal line is drawn parallel to it from the upper edge of the orbit. Three vertical lines are drawn perpendicular to the horizontal ones: 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 occipital protuberance.

The position of the central sulcus of the brain (Rolandic sulcus), between the frontal and parietal lobes, is determined by a 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 groove 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 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 intersection of the anterior vertical with the upper horizontal, and the posterior branch - at the level of intersection of the same; horizontal with back vertical. 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 2.5 cm is set back from the frontal process of the zygomatic bone and a vertical line is drawn. 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 fissure), separating the frontal and parietal lobes from the temporal lobe, the angle formed by the projection line of the central sulcus and the upper horizontal is divided by a bisector. The gap is between the front and rear vertical.

To determine the projection of the parieto-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 groove corresponds to the boundary between the upper and middle third.

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

The stereotaxic apparatus has opened up new prospects for studying the most inaccessible (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 opticum in parkinsonism. The device consists of three parts - a basal ring, a guide arc with an electrode holder and a phantom ring with a coordinate system. First, the surgeon determines superficial (bone) landmarks, then performs a pneumoencephalogram or ventriculogram in two main projections. Using these data, in comparison with the coordinate system of the apparatus, the exact localization of intracerebral structures is determined.

On the internal 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 fossa by the edges of the small wings of the sphenoid bone and the bone ridge (limbus sphenoidalis), lying anterior to the sulcus chiasmatis; the middle fossa is separated from the posterior dorsum of the sella turcica and 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 orbits. The most anterior section of this fossa, at the transition to the cranial vault, borders the frontal sinuses.

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

Of the openings present in the anterior cranial fossa, the foramen caecum is located most anteriorly. This includes a process of the dura mater with a non-permanent emissary connecting the veins of the nasal cavity with the sagittal sinus. Posterior to this opening and to the sides of the crista galli are the openings of the perforated plate (lamina cribrosa) of the ethmoid bone, allowing passage of the nn.olfactorii and a.ethmoidalis anterior from the a.ophthalmica, accompanied by the vein and nerve of the same name (from the first branch of the trigeminal).

For most fractures in 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 when the vasa ethmoidalia is ruptured and severe when the cavernous sinus is damaged. Equally common 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 excessive hemorrhage into the tissue of the orbit, protrusion of the eyeball (exophthalmus) is observed. The leakage of cerebrospinal fluid from the nose indicates a rupture of the processes of the meninges accompanying the olfactory nerves. If the frontal lobe of the brain is also destroyed, then particles of brain matter can escape through the nose.

If the walls of the frontal sinus and the cells of the ethmoidal 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 disorders of smell (anosmia) of varying degrees. Dysfunction of the III, IV, VI nerves and the first branch of the V nerve depends on the accumulation of blood in the tissue of the orbit (strabismus, pupillary changes, anesthesia of the forehead skin). As for the II nerve, it can be damaged by a fracture of the processus clinoideus anterior (at the border with the middle cranial fossa); More often there is hemorrhage in the nerve sheath.

Purulent inflammatory processes affecting the contents of the cranial fossae are often a consequence of the transition of the purulent process from the cavities adjacent to the base of the skull (orbit, 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: in this case, meningitis, epi- and subdural abscess, and abscess of the frontal lobe of the brain can develop. Such an abscess develops as a result of the spread of 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 spread 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 the sphenoid (otherwise the main) sinus, and on the surface facing the cranial cavity it has a depression - the fossa sella, in which the cerebral appendage (pituitary gland) is located. Spreading over the fossa of the sella turcica, the dura mater forms the sella diaphragm (diaphragma sellae). In the center of the latter there is a hole through which the funnel (infundibulum) connects the pituitary gland with the base of the brain. Anterior to the sella turcica, in the 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, there 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) there is the semilunar ganglion of the trigeminal nerve. The cavity in which the node is placed (cavum Meckeli) 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 sinuses of the dura mater in practical terms - the cavernous sinus (sinus cavernosus), into which the superior and inferior ophthalmic veins flow.

Of the openings of the middle cranial fossa, the canalis opticus (foramen opticum - BNA) lies most anteriorly, through which the n.opticus (II nerve) and a.ophathlmica pass into the orbit. Between the small and large wings of the sphenoid bone, a fissura orbitalis superior is formed, through which vv.ophthalmicae (superior et inferior) pass, flowing 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 the n.maxillaris (second branch of the trigeminal nerve), and posterior and somewhat lateral to the foramen rotundum lies 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. Posterior and outward from the oval foramen is the foramen spinosus, which allows the a.meningei media (a.maxillaris) to pass through. Between the apex of the pyramid and the body of the sphenoid bone there is a foramen lacerum, made of cartilage, through which the n.petrosus major (from the n.facialis) passes and often an emissary connecting the plexus pterygoideus with the sinus cavernosus. The canal of the internal carotid artery opens here.

With injuries in the area of ​​the middle cranial fossa, as with fractures in the area 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 running inside the cavernous sinus usually leads to fatal bleeding. There are cases when such severe bleeding does not immediately occur, and then the clinical manifestation of damage to the internal carotid artery inside the cavernous sinus is pulsating bulging eyes. It depends on the fact that blood from the damaged carotid artery penetrates the ophthalmic vein system.

When the pyramid of the temporal bone is fractured and the eardrum is ruptured, bleeding from the ear appears, and when the spurs of the meninges are damaged, cerebrospinal fluid leaks from the ear. When the temporal lobe is crushed, particles of brain matter may be released from the ear.

With 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 facial muscles, and loss of hearing function on the affected side.

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 walls of the middle ear. An important route for the spread of purulent infection is vv.ophthalmicae, the defeat of which leads to thrombosis of the cavernous sinus and disruption of the 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 facet of the pyramid of the temporal bone forms the roof of the tympanic cavity - tegmen tympani. If the integrity of this plate is damaged as a result of chronic suppuration of the middle ear, an abscess can form: either epidural (between the dura mater and the bone) or subdural (under the dura mater). Sometimes diffuse purulent meningitis or an abscess of the temporal lobe of the brain develops. The facial nerve canal is adjacent to 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 pons and medulla oblongata, located in the anterior part of the fossa, on the slope, and the cerebellum, which fills the rest of the fossa.

Of the dural sinuses located in the posterior cranial fossa, the most important are the transverse sinus, which passes into the sigmoid sinus, and the occipital sinus.

The openings of the posterior cranial fossa are located in a certain sequence. Most anteriorly, on the posterior edge of the pyramid of the temporal bone lies the internal auditory opening (porus acusticus internus). The 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 the large occipital foramen (foramen occipitale magnum), through which passes the medulla oblongata with its membranes, aa.vertebrales (and their branches - aa.spinales anteriores et posteriores), plexus venosi vertebrales interni and the spinal roots of the accessory nerve ( n.accessorius). On the side of the foramen magnum there is a foramen canalis hypoglossi, through which n.hypoglossus (XII) and 1-2 veins pass, connecting the plexus venosus vertebralis internus and v.jugularis interna. V is located in or near the sigmoid sulcus. emissaria mastoidea, connecting the occipital vein and the veins of the external base of the skull with the sigmoid sinus.

Fractures in the posterior cranial fossa can cause subcutaneous hemorrhages behind the ear associated with damage to the sutura mastoideooccipitalis. These fractures often do not cause external bleeding, because... the eardrum remains intact. There is no leakage of cerebrospinal fluid or release of particles of brain matter in closed fractures (there are no channels opening outward).

Within the posterior cranial fossa, a purulent lesion of the S-shaped sinus (sinus phlebitis, sinus thrombosis) may 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 purulent process transferring to the sinus when the inner ear is damaged (purulent labyrinthitis). A thrombus developing in the S-shaped sinus can reach the jugular foramen and move 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 (impaired swallowing due to paralysis of the velum and pharyngeal muscles, hoarseness, difficulty breathing and slow pulse, spasms of the sternocleidomastoid and trapezius muscles) . Thrombosis of the S-shaped sinus can also spread to the transverse sinus, which is connected by anastomosis 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 an abscess of the temporal or parietal lobe of the brain.

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

PRINCIPLES OF OPERATIVE INTERVENTIONS IN THE CRANIAL CAVITY

Puncture of the greater 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 the cistern magna for the purpose of x-ray diagnostics (pneumoencephalography, myelography).

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

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

Operation technique. The surgeon feels the protuberantia occipitalis externa and the spinous process of the II cervical vertebra and in this area anesthetizes the soft tissues 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. Using a special needle with a mandrel, an injection is made 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 lifted and again pushed 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 anteriorly, and 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 magna cistern. If cerebrospinal fluid containing blood comes from the needle, the puncture must be stopped. The depth to which the needle must be immersed depends on the age, gender, and constitution of the patient. On average, the puncture depth is 4-5 cm.

To protect against the risk of damage to the medulla oblongata, a special rubber attachment is put on the needle in accordance with the permissible depth of immersion of the needle (4-5 cm).

Cisternal puncture is contraindicated for tumors located in the posterior cranial fossa and in the upper cervical 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 examination, to determine intraventricular pressure, to administer oxygen, air or contrast agents (lipiodol, etc.).

Therapeutic ventriculopuncture is indicated if urgent unloading of the cerebrospinal fluid system is necessary when it is blocked, to remove fluid from the ventricular system for a longer time, i.e. for long-term drainage of the liquor system, as well as for the administration of medications 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 occipital protuberance (corresponding to the sagittal suture) (Fig. 7A,B). Then mark the line of the coronal suture, located 10-11 cm above the brow ridge. 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 soft tissue incision 3-4 cm long is made parallel to the sagittal suture. The periosteum is peeled off with a raspatory and a hole is drilled in the frontal bone with a milling 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 large falciform process with an inclination in the direction of the biauricular line (a conventional line connecting both ear canals) to a depth of 5-6 cm, which is taken into account on the scale marked on the surface of the cannula. When the required depth is reached, the surgeon firmly fixes the cannula with his fingers and removes the mandrel from it. The liquid is normally transparent and is released in rare drops. With dropsy of the brain, cerebrospinal fluid sometimes flows in a stream. Having removed the required amount of cerebrospinal fluid, 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 – location of the burr hole in relation to the coronal and sagittal sutures outside the projection of the sagittal sinus;

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

C – location of the burr hole in relation to the midline and the level of the occipital protuberance (the direction of the needle stroke is indicated in the box);

D – the needle is 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 puncturing the anterior horn of the lateral ventricle (Fig. 7 C,D). First, set a point located 3-4 cm above the occipital buff and 2.5-3.0 cm from the midline to the left or right. This depends on which ventricle is intended to be punctured (right or left).

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

Stopping 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.

Primary surgical treatment of the wound is performed, and a sufficiently wide (5-7 cm) trepanation hole is made in the bone so that intact areas of the sinus are visible. If bleeding occurs, the hole in the sinus is pressed with a tampon. Then they take long gauze strips, which are methodically placed in folds over the bleeding area. Tampons are inserted on both sides of the sinus injury site, placing them between the inner plate of the skull bone and the dura mater. Tampons press the upper wall of the sinus to the lower, causing it to collapse and subsequently form a blood clot in this place. The tampons are removed after 12-14 days.

For small defects in the outer wall of the venous sinus, the wound can be closed with a piece of muscle (for example, temporalis) 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. Applying a vascular suture to the sinus is possible only with small linear tears in its upper wall.

If it is impossible to stop the bleeding using 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 holding back the bleeding by pressing with the index finger or a tampon, quickly expand the defect in the bone with pliers so that the upper longitudinal sinus is open to a sufficient extent. After this, departing from the midline by 1.5-2.0 cm, the dura mater is incised on both sides parallel to the sinus anterior and posterior to the site of injury. Through these incisions, two ligatures are inserted with a thick, sharply curved needle to a depth of 1.5 cm and the sinus is bandaged. Then all the veins flowing into the damaged area of ​​the sinus are ligated.

Dressing a. meningea media.

Indications. Closed and open injuries to 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 based on the Krenlein diagram. According to the general rules of craniotomy, a horseshoe-shaped aponeurotic skin flap with a base on the zygomatic arch is cut out in the temporal region (on the damaged side) and scalped downwards. After this, the periosteum is dissected within the skin wound, several holes are drilled in the temporal bone with a milling cutter, a musculoskeletal flap is formed and broken at the base. Blood clots are removed with a swab and the bleeding vessel is found. Having found the site of damage, they grab the artery above and below the wound with two clamps and bandage it with two ligatures. If there is a subdural hematoma, the dura mater is dissected, blood clots are carefully removed with a stream of saline solution, the cavity is drained and hemostasis is performed. Sutures are placed on the dura mater. The flap is placed in place and the wound is sutured in layers.

Theoretical questions for the lesson:

1. Inner surface of the base of the skull.

2. Meninges of the brain.

3. Venous sinuses of the dura mater.

4. Cranial topography.

5. Clinic of fractures of the base of the skull.

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

Practical part of the lesson:

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

2. Master the construction of the Krenleyn cranial topography diagram 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. How are the anterior, middle and posterior cranial fossae formed?

3. What are the “weak points” of the skull base?

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

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

6. How is the connection between the venous sinuses and the extracranial veins?

7. What are the features of the spread of hematomas in the interthecal spaces?

8. For what purposes is the Kreinlein cranial topography scheme used?

The cerebral cortex is covered with grooves and convolutions (Fig. 22, Fig. 23, Fig. 24). The deepest primary grooves are distinguished, which divide the hemispheres into lobes. The lateral sulcus (Sylvius) separates the frontal lobe from the temporal lobe, the central sulcus (Rolandova) separates the frontal from the parietal. The parieto-occipital sulcus is located on the medial surface of the hemisphere and separates the parietal and occipital lobes; on the superolateral surface there is no clear boundary between these lobes. On the medial surface there is a cingulate sulcus, which passes into the hippocampal sulcus, which limits the olfactory brain from the remaining lobes.

Secondary grooves are less deep; they divide the lobes into convolutions and are located outside the convolutions of the same name. Tertiary (innominate) grooves give the gyri an individual shape and increase the area of ​​their cortex.

The insular lobe is located deep in the lateral sulcus (Fig. 25). It is surrounded on three sides by a circular groove, its surface is indented with grooves and convolutions. Functionally, the insula is connected to the olfactory brain.

Rice. 22. Grooves and convolutions on the superolateral surface.

1. central sulcus (Rolandova)
2. precentral sulcus and gyrus
3. superior frontal sulcus and gyrus
4. middle frontal gyrus
5. inferior frontal sulcus and gyrus
6. tire
7. triangular part
8. orbital surface
9. postcentral boron and gyrus
10. intraparietal sulcus
11. superior parietal lobule
12. inferior parietal lobule
13. supramarginal gyrus
14. angular gyrus
15. lateral groove (Sylvia)
16. superior temporal sulcus and gyrus
17. middle temporal gyrus
18. inferior temporal sulcus and gyrus

Rice. 23. Grooves and convolutions on the medial surface

19. corpus callosum and its sulcus
20. gray matter of the corpus callosum
21. subcallosal area
22. peri-terminal gyrus
23. cingulate gyrus
24. isthmus of the cingulate gyrus
25. hippocampal sulcus (dentate gyrus)
26. paracentral lobule
27. precuneus
28. wedge
29. parieto-occipital sulcus
30. calcarine groove
31. lingular gyrus
32. parahippocampal sulcus and gyrus
33. hook
34. nasal groove
35. medial temporo-occipital
36. lateral temporo-occipital gyrus
37. temporo-occipital sulcus

Fig.24. Furrows and convolutions of the lower surface of the hemispheres brain

1. olfactory groove
2. gyrus rectus
3. orbital grooves
4. orbital gyri (variable)
5. inferior temporal sulcus
6. parahippocampal (collateral) sulcus
7. parahippocampal gyrus
8. temporo-occipital sulcus
9. calcarine groove

Fig.25. Insula

11. circular groove
12. central sulcus
13. long gyrus
14. short convolutions
15. threshold