The grooves of the frontal lobe of the brain. The grooves and convolutions of the cerebral cortex. Brain: functions
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.
| No. | Stages | Time (min.) | Tutorials | Location |
| 1. | Checking workbooks and students’ level of preparation for the practical lesson topic | Workbook | Study room | |
| 2. | Correction of students' knowledge and skills by solving a clinical situation | Clinical situation | Study room | |
| 3. | Analysis and study of material on models, corpses, viewing demonstration videos | Dummies, cadaveric material | Study room | |
| 4. | Test control, solving situational problems | Tests, situational tasks | Study room | |
| 5. | Summing up the lesson | - | Study room |
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 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. Liquorhea 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.
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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?
All the capabilities 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 related to the structure, the understanding of which allows one to correctly diagnose and treat a number of diseases. Therefore, when examining the grooves and convolutions of the brain, specialists try to note the features of their structure, deviations from which will become a sign of pathology.
What is 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. This is how the area of the brain expands while maintaining its volume.
Gyri are the folds that characterize an organ in the final stage of development. Scientists associate their formation with different levels of tension in the brain in childhood.
The grooves are the canals that separate the convolutions. 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 sulci of the brain have the ability to transform. Differences may relate to shape, direction and size.
Structure
When identifying the main elements of the brain, it is better to use a diagram to more clearly understand the overall picture. The primary grooves of the cortex include the main grooves, dividing the organ into two large parts, called hemispheres, and also delimiting the main sections:
- the Sylvian fissure runs between the temporal and frontal lobes;
- Roland's cavity is located on the border between the parietal and frontal parts;
- The parieto-occipital cavity is formed at the junction of the occipital and parietal zones;
- along the cingulate cavity, which passes into the hippocampal cavity, the olfactory brain is found.
The formation of relief always occurs in a certain order. Primary furrows appear starting from the tenth week of pregnancy. First, the lateral one is formed, followed by the central one and others.
In addition to the main grooves, which have distinctive names, a certain number of secondary grooves appear between 24 and 38 weeks of the intrauterine 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 considered factors influencing the relief of the organ.
Formation and functions of the brain convolutions
It has been 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 spoken speech.
Wernicke's center is located here, damage to which leads to the fact that a person ceases to understand what is being said to him. At the same time, you can still pronounce and write down words. The disease is called sensory aphasia.
In the area of the inferior pubic gyrus there is a formation responsible for the reproduction of words, which is called Broca's speech center. If an MRI reveals damage to this brain region, the patient experiences motor aphasia. This means full understanding of what is happening, but the inability to express your thoughts and feelings in words.
This happens when there is a disruption in the blood supply to the cerebral artery.
Damage to all departments responsible for speech can cause complete aphasia, in which a person may lose contact with the outside world due to the inability to communicate with others.
The anterior central gyrus is functionally different from the others. As part of the pyramidal system, it is responsible for performing conscious movements. The functioning of the posterior central eminence is inextricably linked with 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 meaning is associated with visual recognition of the resulting images. It also contains processes that allow sounds to be deciphered. The cingulate gyrus, located above the corpus callosum, is a component of the limbic system.
It is responsible for emotions and control of aggressive behavior.
Memory is of particular importance in human life. She plays an important role in her own education and in the education of new generations. And storing memories would be impossible without the hippocampal gyrus.
Doctors who study neuropathology note that damage to one of the brain regions is more common than 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 disorders.
Lobes of the brain and their functions
Thanks to the grooves and convolutions, the organ inside the cranium is divided into several zones with different purposes. Thus, 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 made by multiple objects. The temporal region contains everything necessary to process the visual and auditory information received. The medial zone is associated with learning, emotional perception and memory.
The midbrain allows you to maintain muscle tone and response to sound and visual stimuli. The posterior part of the organ is divided into the medulla oblongata, the pons and the cerebellum. The dorsolateral lobe is responsible for regulating breathing, digestion, chewing, swallowing and protective reflexes.
General overview of the structure of the cerebral hemispheres
The cerebral hemispheres are the most massive part of the brain. They cover the cerebellum and brain stem. The cerebral hemispheres make up approximately 78% of the total brain mass. During the ontogenetic development of the organism, the cerebral hemispheres develop from the telencephalon of the neural tube, therefore this part of the brain is also called the telencephalon.
The cerebral hemispheres are divided along the midline by a deep vertical fissure into the right and left hemispheres.
In the depths of the middle part, both hemispheres are connected to each other by a large commissure - the corpus callosum. Each hemisphere has lobes; frontal, parietal, temporal, occipital and insula.
The lobes of the cerebral hemispheres are separated from one another by deep grooves. The most important are three deep grooves: the central (Rolandian) separating the frontal lobe from the parietal, the lateral (Sylvian) separating the temporal lobe from the parietal, the parieto-occipital separating the parietal lobe from the occipital on the inner surface of the hemisphere.
Each hemisphere has a superolateral (convex), inferior and internal surface.
Each lobe of the hemisphere has cerebral convolutions separated from each other by grooves. The top of the hemisphere is covered with a cortex - a thin layer of gray matter, which consists of nerve cells.
The cerebral cortex is the youngest formation of the central nervous system in evolutionary terms. In humans it reaches its highest development. The cerebral cortex is of great importance in the regulation of the body’s vital functions, in the implementation of complex forms of behavior and the development of neuropsychic functions.
Under the cortex is the white matter of the hemispheres; it consists of processes of nerve cells - conductors. Due to the formation of cerebral convolutions, the total surface of the cerebral cortex increases significantly. The total area of the cerebral cortex is 1200 cm 2, with 2/3 of its surface located in the depths of the grooves, and 1/3 on the visible surface of the hemispheres. Each lobe of the brain has a different functional significance.
The frontal lobe occupies the anterior parts of the hemispheres. It is separated from the parietal lobe by the central sulcus, and from the temporal lobe by the lateral sulcus. The frontal lobe has four gyri: one vertical - the precentral and three horizontal - the superior, middle and inferior frontal gyri. The convolutions are separated from each other by grooves.
On the lower surface of the frontal lobes, the rectus and orbital gyri are distinguished. The gyrus recta lies between the inner edge of the hemisphere, the olfactory sulcus and the outer edge of the hemisphere.
In the depths of the olfactory sulcus lie the olfactory bulb and the olfactory tract.
The human frontal lobe makes up 25-28% of the cortex; the average weight of the frontal lobe is 450 g.
The function of the frontal lobes is associated with the organization of voluntary movements, motor mechanisms of speech, regulation of complex forms of behavior, and thinking processes. Several functionally important centers are concentrated in the convolutions of the frontal lobe. The anterior central gyrus is a “representation” of the primary motor zone with a strictly defined projection of body parts. The face is “located” in the lower third of the gyrus, the hand is in the middle third, the leg is in the upper third. The trunk is represented in the posterior parts of the superior frontal gyrus. Thus, a person is projected in the anterior central gyrus upside down and head down.
The anterior central gyrus, together with the adjacent posterior and parts of the frontal gyri, plays a very important functional role. It is the center of voluntary movements. In the depths of the cortex of the central gyrus, from the so-called pyramidal cells - the central motor neuron - the main motor path begins - the pyramidal, corticospinal path. The peripheral processes of motor neurons leave the cortex, gather into a single powerful bundle, pass through the central white matter of the hemispheres and enter the brain stem through the internal capsule; at the end of the brainstem they partially decussate (passing from one side to the other) and then descend into the spinal cord. These processes end in the gray matter of the spinal cord. There they come into contact with the peripheral motor neuron and transmit impulses from the central motor neuron to it. Impulses of voluntary movement are transmitted along the pyramidal pathway.
In the posterior sections of the superior frontal gyrus there is also an extrapyramidal center of the cortex, which is closely connected anatomically and functionally with the formations of the so-called extrapyramidal system. The extrapyramidal system is a motor system that assists in voluntary movement. This is a system for “providing” voluntary movements. Being phylogenetically older, the extrapyramidal system in humans provides automatic regulation of “learned” motor acts, maintenance of general muscle tone, readiness of the peripheral motor system to perform movements, and redistribution of muscle tone during movements. In addition, it is involved in maintaining normal posture.
The motor areas of the cortex are located mainly in the precentral gyrus and paracentral lobule on the medial surface of the hemisphere. Primary and secondary areas are distinguished. These fields are motor, but according to their characteristics, according to research from the Brain Institute, they are different. The primary motor cortex contains neurons that innervate the motor neurons of the muscles of the face, trunk and limbs.
It has a clear topographic projection of the muscles of the body. The main pattern of topographic representation is that the regulation of the activity of muscles that provide the most accurate and varied movements (speech, writing, facial expressions) requires the participation of large areas of the motor cortex. Field 4 is completely occupied by the centers of isolated movements, field 6 is only partially occupied.
The preservation of field 4 turns out to be necessary to obtain movements when both field 4 and field 6 are stimulated. In a newborn, field 4 is almost mature. Irritation of the primary motor cortex causes contraction of the muscles of the opposite side of the body (for the muscles of the head, the contraction can be bilateral). When this cortical zone is damaged, the ability to make fine coordinated movements of the limbs and especially the fingers is lost.
The secondary motor cortex has a dominant functional significance in relation to the primary motor cortex, carrying out higher motor functions associated with planning and coordination of voluntary movements. Here, the slowly increasing negative readiness potential, which occurs approximately 1 s before the start of movement, is most recorded. The cortex of area 6 receives the bulk of impulses from the basal ganglia and cerebellum and is involved in the recoding of information about complex movements.
Irritation of the cortex of area 6 causes complex coordinated movements, for example, turning the head, eyes and torso in the opposite direction, cooperative contractions of the flexors or extensors on the opposite side. In the premotor cortex there are motor centers associated with human social functions: the written speech center in the posterior part of the middle frontal gyrus, the Broca motor speech center in the posterior part of the inferior frontal gyrus, which provides speech, as well as the musical motor center, which provides the tone of speech and the ability to sing. The lower part of field b (subfield boron), located in the area of the tire, reacts to the electric current with rhythmic chewing movements. Neurons of the motor cortex receive afferent inputs through the thalamus from muscle, joint and skin receptors, from the basal ganglia and cerebellum. The main efferent output of the motor cortex to the stem and spinal motor centers are the pyramidal cells of layer V.
In the posterior part of the middle frontal gyrus there is the frontal oculomotor center, which controls the concomitant, simultaneous rotation of the head and eyes (the center of rotation of the head and eyes in the opposite direction). Irritation of this center causes the head and eyes to turn in the opposite direction. The function of this center is of great importance in the implementation of the so-called orientation reflexes (or “what is this?” reflexes), which are very important for preserving the life of animals.
The frontal cortex of the cerebral hemispheres also takes an active part in the formation of thinking, the organization of purposeful activities, and long-term planning.
The parietal lobe occupies the superior lateral surfaces of the hemisphere. From the frontal lobe, the parietal lobe is limited in front and to the side by the central sulcus, from the temporal lobe below - by the lateral sulcus, from the occipital - by an imaginary line running from the upper edge of the parieto-occipital sulcus to the lower edge of the hemisphere.
On the superolateral surface of the parietal lobe there are three gyri: one vertical - posterior central and two horizontal - superior parietal and inferior parietal. The part of the inferior parietal gyrus, which encircles the posterior part of the lateral sulcus, is called the supramarginal (supramarginal) region, the part surrounding the superior temporal gyrus is the nodal (angular) region.
The parietal lobe, like the frontal lobe, makes up a significant part of the cerebral hemispheres. In phylogenetic terms, it is divided into an old section - the posterior central gyrus, a new one - the superior parietal gyrus and a newer one - the inferior parietal gyrus.
The function of the parietal lobe is associated with the perception and analysis of sensory stimuli and spatial orientation. Several functional centers are concentrated in the gyri of the parietal lobe.
In the posterior central gyrus, sensitivity centers are projected with a body projection similar to that in the anterior central gyrus. The face is projected in the lower third of the gyrus, the arm and torso are projected in the middle third, and the leg is projected in the upper third. In the superior parietal gyrus there are centers in charge of complex types of deep sensitivity: muscular-articular, two-dimensional spatial sense, a sense of weight and range of motion, a sense of recognizing objects by touch.
Posterior to the upper parts of the posterior central gyrus, a center is located that provides the ability to recognize one’s own body, its parts, their proportions and relative positions.
Fields 1, 2, 3 of the postcentral region constitute the main cortical nucleus of the skin analyzer. Together with field 1, field 3 is the primary, and field 2 is the secondary projection zone of the skin analyzer. The postcentral region is connected by efferent fibers to the subcortical and stem formations, to the precentral and other areas of the cerebral cortex. Thus, the cortical section of the sensitive analyzer is localized in the parietal lobe.
Primary sensory zones are areas of the sensory cortex, irritation or destruction of which causes clear and permanent changes in the sensitivity of the body (analyzer nuclei, according to I.P. Pavlov). They consist mainly of unimodal neurons and form sensations of the same quality. In the primary sensory zones there is usually a clear spatial (topographic) representation of body parts and their receptor fields.
Around the primary sensory zones there are less localized secondary sensory zones, the neurons of which respond to the action of several stimuli, i.e. they are multimodal.
The most important sensory area is the parietal cortex of the postcentral gyrus and the corresponding part of the paracentral lobule on the medial surface of the hemispheres, which is designated as somatosensory area I. Here there is a projection of the skin sensitivity of the opposite side of the body from tactile, pain, temperature receptors, interoceptive sensitivity and sensitivity of the musculoskeletal system - from muscle, joint, tendon receptors.
In addition to somatosensory area I, a smaller somatosensory area II is distinguished, located at the border of the intersection of the central sulcus with the upper edge of the temporal lobe, in the depth of the lateral sulcus. The degree of localization of body parts is less pronounced here.
Praxis centers are located in the inferior parietal lobe. Praxis refers to purposeful movements that have become automated in the process of repetition and exercise, which are developed in the process of learning and constant practice throughout an individual’s life. Walking, eating, dressing, the mechanical element of writing, various types of work activities (for example, the movements of a driver while driving a car, mowing, etc.) are praxis. Praxis is the highest manifestation of the motor function inherent in humans. It is carried out as a result of the combined activity of various areas of the cerebral cortex.
In the lower parts of the anterior and posterior central gyri there is the center of the analyzer of interoceptive impulses of internal organs and blood vessels. The center has close connections with subcortical vegetative formations.
The temporal lobe occupies the inferolateral surface of the hemispheres. From the frontal and parietal lobes, the temporal lobe is limited by the lateral sulcus. On the superolateral surface of the temporal lobe there are three gyri: superior, middle and inferior.
The superior temporal gyrus is located between the Sylvian and superior temporal fissures, the middle one is between the superior and inferior temporal sulci, and the inferior one is between the inferior temporal sulcus and the transverse medullary fissure. On the lower surface of the temporal lobe, the inferior temporal gyrus, the lateral occipitotemporal gyrus, and the hippocampal gyri (seahorse leg) are distinguished.
The function of the temporal lobe is associated with the perception of auditory, gustatory, olfactory sensations, analysis and synthesis of speech sounds, and memory mechanisms. The main functional center of the superior lateral surface of the temporal lobe is located in the superior temporal gyrus. The auditory, or gnostic, speech center (Wernicke's center) is located here.
A well-studied primary projection zone is the auditory cortex, which is located deep in the lateral sulcus (cortex of Heschl's transverse temporal gyrus). The projection cortex of the temporal lobe also includes the center of the vestibular analyzer in the superior and middle temporal gyri.
The olfactory projection area is located in the hippocampal gyrus, especially in its anterior section (the so-called uncus). Next to the olfactory projection zones are the gustatory zones.
The temporal lobes play an important role in organizing complex mental processes, in particular memory.
The occipital lobe occupies the posterior parts of the hemispheres. On the convex surface of the hemisphere, the occipital lobe has no sharp boundaries separating it from the parietal and temporal lobes, with the exception of the upper part of the parieto-occipital sulcus, which, located on the inner surface of the hemisphere, separates the parietal lobe from the occipital lobe. The grooves and convolutions of the superolateral surface of the occipital lobe are not constant and have a variable structure. On the inner surface of the occipital lobe there is a calcarine groove that separates the cuneus (a triangular lobule of the occipital lobe) from the lingual gyrus and the occipitotemporal gyrus.
The function of the occipital lobe is associated with the perception and processing of visual information, the organization of complex processes of visual perception - in this case, the upper half of the retina is projected in the wedge area, which perceives light from the lower fields of vision; in the region of the lingular gyrus there is the lower half of the retina of the eye, which perceives light from the upper fields of vision.
The primary visual area is located in the occipital cortex (the cortex of part of the sphenoid gyrus and the lingual lobule). Here there is a topical representation of retinal receptors. Each point of the retina corresponds to its own section of the visual cortex, while the macula zone has a relatively large area of representation. Due to the incomplete decussation of the visual pathways, the same halves of the retina are projected into the visual area of each hemisphere. The presence of a retinal projection in both eyes in each hemisphere is the basis of binocular vision. The cortex of the secondary visual area is located near area 17. The neurons of these zones are multimodal and respond not only to light, but also to tactile and auditory stimuli. In this visual area, various types of sensitivity are synthesized, more complex visual images arise and their recognition is carried out.
The island, or the so-called closed lobule, is located in the depths of the lateral sulcus. The insula is separated from adjacent neighboring sections by a circular groove. The surface of the insula is divided by its longitudinal central groove into anterior and posterior parts. A taste analyzer is projected in the island.
Limbic cortex. On the inner surface of the hemispheres above the corpus callosum is the cingulate gyrus. This gyrus passes through the isthmus behind the corpus callosum into the gyrus near the seahorse - the parahippocampal gyrus. The cingulate gyrus, together with the parahippocampal gyrus, makes up the vaulted gyrus.
The limbic cortex is united into a single functional system - the limbic-reticular complex. The main function of these parts of the brain is not so much to provide communication with the outside world, but to regulate the tone of the cortex, drives and affective life. They regulate complex, multifaceted functions of internal organs and behavioral reactions. The limbic-reticular complex is the most important integrative system of the body. The limbic system is also important in the formation of motivation. Motivation (or internal drive) includes complex instinctive and emotional reactions (food, defensive, sexual). The limbic system is also involved in the regulation of sleep and wakefulness.
The limbic cortex also performs an important function of smell. The sense of smell is the perception of chemicals in the air. The human olfactory brain provides the sense of smell, as well as the organization of complex forms of emotional and behavioral reactions. The olfactory brain is part of the limbic system.
The corpus callosum is an arcuate thin plate, phylogenetically young, connecting the median surfaces of both hemispheres. The elongated middle part of the corpus callosum at the back becomes thickened, and at the front it bends and bends downward in an arched manner. The corpus callosum connects the phylogenetically youngest parts of the hemispheres and plays an important role in the exchange of information between them.
Separates the frontal lobe from the parietal lobe deep central groove, sulcus centralis.
It begins on the medial surface of the hemisphere, passes to its superolateral surface, runs along it slightly obliquely, from back to front, and usually does not reach the lateral sulcus of the brain.
Approximately parallel to the central sulcus is located precentral sulcus,sulcus precentralis, but it does not reach the upper edge of the hemisphere. The precentral sulcus borders the precentral gyrus in front, gyrus precentralis.
Top and bottom frontal grooves, sulci frontales superior et inferior, are directed from the precentral sulcus forward.
They divide the frontal lobe into the superior frontal gyrus, gyrus frontalis superior, which is located above the superior frontal sulcus and extends to the medial surface of the hemisphere; middle frontal gyrus, gyrus frontalis medius, which is bounded by the superior and inferior frontal sulci. The orbital segment of this gyrus passes onto the inferior surface of the frontal lobe. In the anterior parts of the middle frontal gyrus, the upper and lower parts are distinguished. inferior frontal gyrus, gyrus frontalis inferior, lies between the inferior frontal sulcus and the lateral sulcus of the brain and the branches of the lateral sulcus of the brain are divided into a number of parts.
Lateral sulcus, sulcus lateralis, is one of the deepest grooves in the brain. It separates the temporal lobe from the frontal and parietal lobes. The lateral groove lies on the superolateral surface of each hemisphere and runs from top to bottom and anteriorly.
In the depths of this furrow there is a depression - lateral fossa cerebrum, fossa lateralis cerebri, the bottom of which is the outer surface of the island.
Small grooves called rami extend upward from the lateral sulcus. The most constant of them are the ascending branch, ramus ascendens, and the anterior branch, ramus anterior; the superoposterior part of the groove is called the posterior branch, ramus posterior.
inferior frontal gyrus, within which the ascending and anterior branches pass, is divided by these branches into three parts: the posterior - tegmental part, pars opercularis, limited in front by the ascending branch; middle - triangular part, pars triangularis, lying between the ascending and anterior branches, and the anterior orbital part, pars orbitalis, located between the horizontal branch and the inferolateral edge of the frontal lobe.
Parietal lobe lies posterior to the central sulcus, which separates it from the frontal lobe. The parietal lobe is delimited from the temporal lobe by the lateral sulcus of the brain, and from the occipital lobe by part of the parieto-occipital sulcus, sulcus parietooccipitalis.
Runs parallel to the precentral gyrus postcentral gyrus, gyrus postcentralis, bounded posteriorly by the postcentral sulcus, sulcus postcentralis.
From it posteriorly, almost parallel to the longitudinal fissure of the cerebrum, runs intraparietal sulcus, sulcus intraparietalis, dividing the posterosuperior parts of the parietal lobe into two gyri: superior parietal lobule, lobulus parietalis superior, lying above the intraparietal sulcus, and inferior parietal lobulus, lobulus parietalis inferior, located downward from the intraparietal sulcus.
In the inferior parietal lobule there are two relatively small gyri: supramarginal gyrus, gyrus supramarginalis, lying anteriorly and closing the posterior sections of the lateral groove, and located posterior to the previous one angular gyrus, gyrus angularis, which closes the superior temporal sulcus.
Between the ascending branch and the posterior branch of the lateral sulcus of the brain there is a section of the cortex designated as frontoparietal operculum frontoparietale. It includes the posterior part of the inferior frontal gyrus, the lower parts of the precentral and postcentral gyri, and the lower part of the anterior part of the parietal lobe.
Occipital lobe on the convex surface has no boundaries separating it from the parietal and temporal lobes, with the exception of the upper part of the parieto-occipital sulcus, which is located on the medial surface of the hemisphere and separates the occipital lobe from the parietal lobe. All three surfaces occipital lobe: convex lateral, flat medial And concave lower, located on the tentorium of the cerebellum, have a number of grooves and convolutions.
The grooves and convolutions of the convex lateral surface of the occipital lobe are variable and often unequal in both hemispheres.
The largest of the furrows- transverse occipital groove, sulcus occipitalis transversus. Sometimes it is a posterior continuation of the intraparietal sulcus and in the posterior section becomes inconstant semilunar sulcus, sulcus lunatus.
Approximately 5 cm anterior to the pole of the occipital lobe on the lower edge of the superolateral surface of the hemisphere there is a depression - preoccipital notch, incisura preoccipitalis.
Temporal lobe has the most pronounced boundaries. It distinguishes convex lateral surface and concave lower.
The obtuse pole of the temporal lobe faces forward and slightly downward. The lateral cerebral sulcus sharply demarcates the temporal lobe from the frontal lobe.
Two grooves located on the superolateral surface: superior temporal sulcus, sulcus temporalis superior, and inferior temporal sulcus, sulcus temporalis inferior, following almost parallel to the lateral sulcus of the brain, divide the lobe into three temporal gyri: top, middle and bottom, gyri temporales superior, medius et inferior.
Those parts of the temporal lobe, which with their outer surface are directed towards the lateral sulcus of the brain, are cut by short transverse temporal sulci, sulci temporales transversi. Between these grooves lie 2-3 short transverse temporal gyri, gyri temporales transversi, associated with the convolutions of the temporal lobe and the insula.
Insula (islet) lies at the bottom of the lateral fossa big brain, fossa lateralis cerebri.
It is a three-sided pyramid, facing its apex - the pole of the insula - anteriorly and outwardly, towards the lateral sulcus. From the periphery, the insula is surrounded by the frontal, parietal and temporal lobes, which participate in the formation of the walls of the lateral sulcus of the brain.
The base of the island is surrounded on three sides circular groove of the insula, sulcus circularis insulae, which gradually disappears near the lower surface of the island. In this place there is a small thickening - threshold of the island, limen insulae, lying on the border with the lower surface of the brain, between the insula and the anterior perforated substance.
The surface of the insula is cut by a deep central groove of the insula, sulcus centralis insulae. This furrow divides island on front, large, and back, smaller, parts.
On the surface of the insula there are a significant number of smaller convolutions of the insula, gyri insulae. The anterior part has several short convolutions of the insula, gyri breves insulae, posterior - often one long gyrus of the insula, gyrus longus insulae.
Sulci and convolutions of the brain, superolateral surface
1
. Lateral groove, sulcus lateralis (Sylvian groove).
2
. Tegmental part, pars opercularis,
frontal operculum, operculum frontale.
3
. Triangular part, pars triangularis.
4
. Orbital part, pars orbitalis.
5
. Inferior frontal gyrus, gyrus frontalis inferior.
6
. Inferior frontal sulcus, suicus frontalis inferior.
7
. Superior frontal sulcus, suicus frontalis superior.
8
. Middle frontal gyrus, gyrus frontalis medius.
9
. Superior frontal gyrus, gyrus frontalis superior.
10
. Inferior precentral sulcus, sulcus precentralis inferior.
11
. Precentral gyrus, gyrus precentralis (anterior).
12
. Superior precentral sulcus, sulcus precentralis superior.
13
. Central sulcus, sulcus centralis (Roland's sulcus).
14
. Postcentral gyrus, gyrus postcentralis (gyrus centralis posterior).
15
. Intraparietal sulcus, sulcus intraparietalis.
16
. Superior parietal lobule, lobulus parietalis superior.
17
. Inferior parietal lobule, lobulus parietalis inferior.
18
. Supramarginal gyrus, gyrus supramarginalis.
19
. Angular gyrus, gyrus angularis.
20
. Occipital pole, polus occipitalis.
21
. Inferior temporal sulcus, suicus temporalis inferior.
22
. Superior temporal gyrus, gyrus temporalis superior.
23
. Middle temporal gyrus, gyrus temporalis medius.
24
. Inferior temporal gyrus, gyrus temporalis inferior.
25
. Superior temporal sulcus, suicus temporalis superior.
The grooves and convolutions of the medial and inferior surface of the right hemisphere of the cerebrum.
2 - beak of the corpus callosum,
3 - genu corpus callosum,
4 - trunk of the corpus callosum,
5 - groove of the corpus callosum,
6 - cingulate gyrus,
7 - superior frontal gyrus,
8 - cingulate groove,
9 - paracentral lobule,
10 - cingulate groove,
11 - precuneus,
12 - parieto-occipital sulcus,
14 - calcarine groove,
15 - lingual gyrus,
16 - medial occipitotemporal gyrus,
17 - occipitotemporal groove,
18 - lateral occipitotemporal gyrus,
19 - hippocampal sulcus,
20 - parahippocampal gyrus.
Brain stem (sagittal section)
1 - medulla oblongata; 2 - bridge; 3 - cerebral peduncles; 4 - thalamus; 5 - pituitary gland; 6 - projection of the nuclei of the subtubercular region; 7 - corpus callosum; 8 - pineal body; 9 - tubercles of the quadrigeminal; 10 - cerebellum.
Brain stem (posterior view).
1. thalamus
2. anterior tubercle
3. pillow
4. medial geniculate body
5. lateral geniculate body
6. end strip
7. caudate nuclei of the hemispheres
8. brain strip
9. pineal gland
10. leash triangle
11. leash
12. III ventricle
13. soldering of leashes
14. tubercles of the quadrigeminal
Brain stem (posterior view)
A. MEDULA oblongata:
1. posterior median sulcus
2. thin beam
3. thin tubercle
4. wedge-shaped beam
5. wedge-shaped tubercle
6. intermediate groove
7. valve
8. inferior cerebellar peduncles
9. rhomboid fossa
10. posterolateral groove
11. choroid plexus
B. BRIDGE:
12. middle cerebellar peduncle
13. superior cerebellar peduncles
14. superior medullary velum
15. bridle
16. auditory loop triangle
C. MIDDLE BRAIN:
17. visual hillocks
18. auditory tubercles
19. cerebral peduncles
Brainstem (lateral side)
15. quadrigeminal
16. cerebral peduncle
17. thalamic cushion
18. pineal gland
19. medial geniculate bodies (auditory)
20. medial roots
21. lateral geniculate bodies (visual)
22. lateral roots (handles)
23. optic tract
Brainstem (sagittal section)
7. anterior commissure
8. mastoid bodies
9. funnel
10. neurohypophysis
11. adenohypophysis
12. optic chiasm
13. previsional field
14. pineal gland
Sagittal section of the brain.
1.trunk of the corpus callosum
2. roller
3. knee
4. beak
5. lamina terminalis
6. anterior commissure of the brain
7. vault
8. vault pillars
9. mamillary bodies
10. transparent partition
11. thalamus
12. interthalamic commissure
13. hypothalamic sulcus
14. gray tubercle
15. funnel
16. pituitary gland
17. optic nerve
18. Monroe's hole
19. pineal gland
20. epiphyseal commissure
21. posterior commissure of the brain
22. quadrigeminal
23. Sylvian aqueduct
23. Sylvian aqueduct
24. cerebral peduncle
25. bridge
26. medulla oblongata
27. cerebellum
28. fourth ventricle
29. top sail
29. top sail
30. plexus
31. lower sail
Brain (cross section):
1 - island;
2 - shell;
3 - fence;
4 - outer capsule;
5 - globus pallidus;
6 - III ventricle;
7 - red core;
8 - tire;
9 - midbrain aqueduct;
10 - roof of the midbrain;
11 - hippocampus;
12 – cerebellum
1 - internal capsule;
2 - island;
3 - fence;
4 - outer capsule;
5 - visual tract;
6 - red core;
7 - black substance;
8 - hippocampus;
9 - cerebral peduncle;
10 - bridge;
11 - middle cerebellar peduncle;
12 - pyramidal tract;
13 - olive kernel;
14 – cerebellum.
Structure of the medulla oblongata
1 - olivocerebellar tract;
2 - olive kernel;
3 - olive kernel gate;
4 - olive;
5 - pyramidal tract;
6 - hypoglossal nerve;
7 - pyramid;
8 - anterior lateral groove;
9 - accessory nerve
Medulla oblongata (horizontal section)
11. seam
12. medial loop
13. lower olive
14. medial olive
15. dorsal olive
16. reticular formation
17. medial longitudinal fasciculus
18. dorsal longitudinal fasciculus
Structure of the cerebellum:
a - bottom view,
b - horizontal section:
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Cerebellar lobes
Worm slices
Hemisphere lobes
Front
11. uvula cerebellum
12. ligamentous gyrus
13. central
14. wings of the central lobule
15. top of the slide
16. front quadrangular
Rear
18. back quadrangular
19. leaf
20. superior lunate
21. tubercle
22. inferior lunate
23. pyramid
24. thin, digastric (D)
26. tonsil
Shred-nodular
25. sleeve
28. shred, leg, near-shred
27. knot
Cerebellar nuclei (on the frontal section).
A. Diencephalon
B. Midbrain
C. Cerebellum
12. worm
13. hemispheres
14. furrows
15. bark
16. white matter
17. upper legs
18. tent cores
19. spherical kernels
20. cork kernels
21. dentate nuclei
| 1 - cerebral peduncle; |
| Rice. 261. Cerebellum (vertical section): 1 - superior surface of the cerebellar hemisphere; |
The thalamus and other parts of the brain in a midline longitudinal section of the brain:
1- Hypothalamus; 2- Cavity of the third ventricle; 3- anterior (white commissure);
4- Brain vault; 5- Corpus callosum; 6- Interthalamic fusion;
7- Thalamus; 8- Epithalamus; 9- Midbrain; 10- Bridge; 11- Cerebellum;
12- Medulla oblongata.
The fourth ventricle (venticulus quartis) and the vascular base of the fourth ventricle (tela chorioidea ventriculi quarti).
View from above:
1-lingula of the cerebellum;
2-upper brain sail;
3rd fourth ventricle;
4-middle cerebellar peduncle;
5-choroid plexus of the fourth ventricle;
6-tubercle of the sphenoid nucleus;
7-tuberculous nucleus;
8-posterior intermediate groove;
9-wedge beam;
10-lateral (lateral) funiculus;
11-thin bun;
12-posterior median sulcus;
13-posterior lateral groove;
14-median opening (aperture) of the fourth ventricle;
15-vascular base of the fourth ventricle;
16-superior (anterior) cerebellar peduncle;
17 trochlear nerve;
18-inferior colliculus (roof of the midbrain);
19-frenulum of the superior medullary velum;
20-superior colliculus (roof of the midbrain).
IV ventricle:
1 - roof of the midbrain;
2 - median groove;
3 - medial eminence;
4 - superior cerebellar peduncle;
5 - middle cerebellar peduncle;
6 - facial tubercle;
7 - inferior cerebellar peduncle;
8 - wedge-shaped tubercle of the medulla oblongata;
9 - thin tubercle of the medulla oblongata;
10 - wedge-shaped fascicle of the medulla oblongata;
11 - thin fascicle of the medulla oblongata
Superior surface of the cerebral hemispheres
(red - frontal lobe; green - parietal lobe; blue - occipital lobe):
1 - precentral gyrus; 2 - superior frontal gyrus; 3 - middle frontal gyrus; 4 - postcentral gyrus; 5 - superior parietal lobule; 6 - inferior parietal lobule; 7 - occipital gyri; 8 - intraparietal sulcus; 9 - postcentral sulcus; 10 - central groove; 11 - precentral groove; 12 - inferior frontal sulcus; 13 - superior frontal sulcus.
The inferior surface of the cerebral hemispheres
(red - frontal lobe; blue - occipital lobe; yellow - temporal lobe; lilac - olfactory brain):
1 - olfactory bulb and olfactory tract; 2 - orbital gyri; 3 - inferior temporal gyrus; 4 - lateral occipitotemporal gyrus; 5 - parahippocampal gyrus; 6 - occipital gyri; 7 - olfactory groove; 8 - orbital grooves; 9 - inferior temporal sulcus.
Lateral surface of the right hemisphere of the cerebrum
Red - frontal lobe; green - parietal lobe; blue - occipital lobe; yellow - temporal lobe:
1 - precentral gyrus; 2 - superior frontal gyrus; 3 - middle frontal gyrus; 4 - postcentral gyrus; 5 - superior temporal gyrus; 6 - middle temporal gyrus; 7 - inferior temporal gyrus; 8 - tire; 9 - superior parietal lobule; 10 - inferior parietal lobule; 11 - occipital gyri; 12 - cerebellum; 13 - central groove; 14 - precentral sulcus; 15 - superior frontal sulcus; 16 - inferior frontal sulcus; 17 - lateral groove; 18 - superior temporal sulcus; 19 - inferior temporal sulcus.
Medial surface of the right hemisphere of the cerebrum
(red - frontal lobe; green - parietal lobe; blue - occipital lobe; yellow - temporal lobe; lilac - olfactory brain):
1 - cingulate gyrus; 2 - parahippocampal gyrus; 3 - medial frontal gyrus; 4 - paracentral lobule; 5 - wedge; 6 - lingual gyrus; 7 - medial occipitotemporal gyrus; 8 - lateral occipitotemporal gyrus; 9 - corpus callosum; 10 - superior frontal gyrus; 11 - occipitotemporal groove; 12 - groove of the corpus callosum; 13 - cingulate groove; 14 - parieto-occipital groove; 15 - calcarine groove.
Frontal section of the diencephalon
15. III-ventricle
16. interthalamic commissure
17. plates of white matter
18. front horns
19. median nuclei
20. ventrolateral nuclei
21. subthalamic nuclei
Insula
11. circular groove
12. central sulcus
13. long gyrus
14. short convolutions
15. threshold
BRIDGE (cross section)
A. basilar part
B. axle cover
C. trapezoid body
IV v - fourth ventricle
20. medial longitudinal fasciculus
21. superior cerebellar peduncles
22. seam
23. cross fibers
24. bridge cores
25. longitudinal fibers
26. reticular formation
27. medial loop
28. lateral loop
29. rubrospinal put
30. tectospinal tract
Cross section of the midbrain
K. roof
P. tire
N. cerebral peduncle
13. Sylvian aqueduct
14. Sylvian aqueduct
III. nucleus of the oculomotor n.
IV. trochlear nerve nucleus
15. posterior longitudinal beam
16. medial longitudinal p.
17. medial loop
18. lateral loop
19. red kernels
20. substantia nigra
21. tectospinal tract
22. rubrospinal tract
23. reticular formation
24. frontopontine tract
25. corticonuclear pathway
26. corticospinal tract
27. occipito-parieto-temporo-pontine
28. gray and white matter
29. pretectal nuclei
30. spinothalamic tr.
31. oculomotor nerve
Topography of the bottom of the rhomboid fossa
1. top sail
2. lower sail
3. choroid plexus
4. superior cerebellar peduncles
5. middle cerebellar peduncles
6. inferior cerebellar peduncles
7. median sulcus
8. medial eminence
9. border furrow
10. cranial fossa
11. caudal fossa
12. bluish place
13. vestibular field
14. brain stripes
15. facial tubercle
16. triangle of the hyoid n.
17. wandering triangle n.
18. independent cord
19. backmost field
|
1 - superior cerebellar peduncle;
2 - pyramidal tract;
3 - peduncle of the telencephalon;
4 - middle cerebellar peduncle;
5 - bridge;
6 - inferior cerebellar peduncle;
7 - olive;
8 - pyramid;
9 - anterior median fissure