Restoring the balance of the dura mater. Meninges Comparison with pia mater

Anatomy and physiology important role allocated to the membranes of the brain (spinal and brain). Their features, structure and functions are given Special attention, since the functioning of the entire human body depends on them.

shell?

The meninga is the connective tissue membranous structure that surrounds both the spinal cord and the brain. It could be as follows:

• hard;
• arachnoid;
• soft or vascular.

Each of these species is present in both the brain and the spinal cord and is a single entity that passes from one brain to another.

Anatomy of the membrane covering the brain

Solid meninges The brain is a formation with a dense consistency, which is located under the inner surface of the skull. Its thickness in the arch area varies from 0.7 to 1 mm, and at the base of the cranial bones - from 0.1 to 0.5 mm. In places where there are openings, vascular grooves, protrusions and sutures, as well as at the base of the skull, it fuses with the bones, and in other areas its connection with the bones of the skull is looser.

During the development of pathologies, detachment of the described membrane from the cranial bones may occur, resulting in the formation of a gap between them, which is called the epidural space. In places where it is present, when the integrity of the cranial bones is violated, the formation of epidural hematomas occurs.

The inside walls of the solid are smoother than the outside. There it loosely connects with the one underneath it. arachnoid with the help of a multilayer accumulation of specific cells, rare connective tissue filaments, thin vascular stems and nerves, as well as pachyonic granulations of the arachnoid membrane. Normally, there is no space or gap between these two membranes.

In some places, delamination of the dura mater of the brain is possible, resulting in the formation of two sheets. Between them there is a gradual formation of venous sinuses and the trigeminal cavity - the location of the trigeminal node.

Processes extending from the hard shell

Between brain formations 4 main processes extend from the dura mater. These include:

• Sickle cerebri. Its location is the sagittal plane, located between the hemispheres. Its front part enters this plane especially deeply. In the place where the cockscomb is located, located on ethmoid bone, is the beginning of this process. Next, its convex edge is attached to the lateral ribs of the groove located on the superior sagittal sinus. This process of the meninges reaches the occipital protrusion and then passes into outer surface, which forms the tentorium of the cerebellum.

• Falx cerebellum. It originates from the inner occipital protrusion and along its ridge goes to the posterior edge of the large opening in the back of the head. There it passes into two folds of the dura mater, the task of which is to limit the posterior opening. The cerebellar falx is located between the cerebellar hemispheres in the area where its posterior notch is located.
• tentorium of the cerebellum. This process of the dura mater stretches over the posterior fossa cranial surface, between the edges of the temporal bones, as well as the grooves located on the transverse sinuses of the occipital bone. It separates the cerebellum from the occipital lobes. The tentorium of the cerebellum looks like a horizontal plate with an upward middle part. Its free edge, located in front, has a concave surface, forming a notch of the tentorium, which limits its opening. This is the location of the brain stem.
• Seat diaphragm. The process received this name due to the fact that it is stretched over the sella turcica and forms its so-called roof. Below the diaphragm sella is the pituitary gland. In its middle there is a hole through which a funnel passes, holding the pituitary gland.

Anatomy of the spinal cord membrane

The thickness of the dura mater is less than that of the brain. With its help, a sac (dural) is formed, which houses the entire spinal cord. A thread of hard shell extends from this sac, leading downwards, and is subsequently attached to the coccyx.

There is no fusion between the dura mater and the periosteum, resulting in the formation of an epidural space, which is filled with loose, unformed connective tissue and internal venous vertebral plexuses.

With the help of the hard shell, the formation of fibrous sheaths located near the roots is carried out spinal cord.

Functions of hard shells

The main function of the dura mater is to protect the brain from mechanical damage. They perform the following role:

• Ensure blood circulation and its removal from the vessels of the brain.
• Thanks to their dense structure, they protect the brain from external influences.

Another function of the dura maters is to create a shock-absorbing effect as a result of cerebrospinal fluid circulation (in the spinal cord). And in the brain they take part in the formation of processes that delimit important areas of the brain.

Pathologies of the dura mater of the brain

Pathologies of the meninges may include developmental disorders, damage, diseases associated with inflammation, and tumors.

Developmental disorders are quite rare and often occur against the background of changes in the formation and development of the brain. In this case hard shell the brain remains underdeveloped and defects may form in the skull itself (windows). In the spinal cord, developmental pathology can lead to local splitting of the dura mater.

Damage may result from traumatic brain or spinal cord injury.

Inflammation in the dura mater is called pachymeningitis.

Inflammatory disease in the lining of the brain

Often the reason inflammatory process the dura mater of the brain becomes infected.

In the practice of doctors, patients develop hypertrophic (basal) pachymeningitis or HPM. It is a manifestation of pathology in the described structure. Most often, men in young or middle age are affected by this disease.

The clinical picture of basal pachymeningitis is represented by inflammation of the membranes. This rare pathology is characterized by local or diffuse thickening of the dura mater at the base of the brain, most often in places where the falx or cerebellar tentorium is located.

In the case of the autoimmune variant of HPM, examining the cerebrospinal fluid, pleocytosis can be detected, increased content proteins, and no microbial growth.

Pathology of the dura mater of the spinal cord

External pachymeningitis often develops. During its development, inflammation occurs, affecting the epidural tissue, after which inflammation spreads to the entire surface of the dura mater of the spinal cord.

Diagnosing the disease is quite difficult. But the incidence of spinal pachymeningitis is higher than the development of pathologies associated with inflammation in the dura mater of the brain. To identify it, it is necessary to build on the patient’s complaints, medical history, and laboratory research cerebrospinal fluid and blood.

Tumors

The dura mater can undergo the development of both benign and malignant tumors. Thus, in the described structures or their processes, meningiomas can develop, growing towards the brain and compressing it.

Damage to the dura mater malignant tumors most often occurs due to metastases, resulting in the formation of single or multiple nodes.

Diagnosis of this pathology is carried out by examining cerebral or cerebrospinal fluids for the presence of tumor cells.

The dura mater (DRM) is a very strong connective tissue structure with external and internal layers.

Inside cranium this layer is tightly attached to the bone tissue, growing into the periosteum of its base.

The inner side of the meninges adjacent to the brain is smoothed with the presence of endothelium.

General information

In the middle of the dura mater and the arachnoid membrane there is a subdural cavity of insignificant width filled with a small amount of interlayer fluid - cerebrospinal fluid.
In some fragments, the dura mater grows in the form of processes into the narrow spaces of the brain. In areas where the processes grow, the membrane bifurcates, forming triangular sinuses also covered with endothelium - the dura mater sinuses.

The plates of these tanks are very tightly stretched and do not move, even when cutting.

These tanks are designed to contain venous blood, which gradually drains from the veins supplying nutrition and oxygen to the brain in the skull. From the sinuses, blood flows into the internal jugular veins; in addition, there is communication between these recesses and the arteries outer surface heads thanks to spare arterial graduates.

Structure

The hard shell is a fibrous type protective plate that penetrates from the inside to the bone tissue of the skull. Forms processes that grow into the cranial space: a crescent-shaped continuation of the cerebrum, a continuation of the cerebellum in the form of a sickle, tentorium, sellar plate, etc.

Between the dura mater and the bone tissue of the skull there is an epidural cavity, in fact meaning the unification of multiple spaces separated by connective tissue bases (tractions). These areas develop after birth, during the closure of pulsating fontanelles. At the arch, these spaces expand, since there are not so many cartilaginous foundations here. On the vault of the skull, and in the direction of the venous sinuses and cranial joints, the mentioned cavities become narrower and the interweaving of the cords is very dense. All connecting cavities are provided with endothelium and filled with fluid. Using experiments, it has been scientifically proven that epidural fluid flows into the external network of small vessels of the dura mater.

The dura mater of the brain is divided into two more or less reinforced plates, of which the outer one is the periosteum of the skull. Each of the plates is delaminated. Without exception, all layers are equipped with fibrillar protein, essentially the basis of the connecting material. They are connected into bundles, placed equally horizontally in each layer. In neighboring layers, the beams intersect, forming a cross.

Sinuses and processes of the dura mater of the brain

The following are considered to be the processes of the dura mater:

1. A large crescent-shaped continuation, or the crescent-shaped process of the largest hemispheres of the brain, is located between both large parts of the brain;
2. A small falciform process, or a falciform process near the cerebellum, extends into the cavity between the cerebellar hemispheres, joining the bone tissue of the occiput from the internal occipital indentation to the large foramen of the occiput;
3. Cerebellar tentorium - located between the parts cerebral hemispheres brain at the back of the head and cerebellum;
4. The plate is located above the sella turcica; in the middle there is a hole through which a funnel runs.

Sinuses (lacunae) of the dura mater of the brain, formed due to the splitting of the dura mater into two strands, are essentially channels through which blood from the veins is drained from the head into the internal dual veins.

The hard shell plates that form the lacunae are tightly reinforced and do not move. Therefore, these sinuses are visible in the section. They are not equipped with valves. This structure of these tanks allows venous blood to flow freely from the brain, completely independent of pressure surges inside the skull. On the inner walls of the bone tissue of the skull, in the areas where these recesses of the hard shell are located, there are proper tentories. IN medical practice The following names of dura sinuses are used:

1. The superior vertically dividing sinus is located longitudinally along the entire upper-outer border of the falx of the cerebral hemispheres, from the edge resembling the cockscomb of the ethmoid bone to the indentation of the occiput inside. In the anterior parts, this tank is equipped with anastomoses with veins of the paranasal space. Its termination at the rear is included in the transverse manifold.
2. The lower vertically dividing lacuna is located inside the lower spacious border of the falx of the cerebral hemisphere. It is much smaller than the top one.
3. The straight sinus is located vertically in the splitting of the cerebellar membrane in the direction of the attachment of the falx of the cerebral hemisphere to it. This collector combines the posterior ends of the superior and inferior sagittal sinuses.
4. located in the part of the separation of the cerebellar plate from the dura mater of the brain. On inside The scales of the bone tissue of the back of the head are related to this depression by the extensive groove of the transverse sinus.
5. The occipital lacuna lies at the bottom of the cerebellar falx. Descending longitudinally from the inside of the occipital border, this tank is located to the posterior border of the large opening of the occiput, where it diverges into two grooves that frame this opening at the back and on both sides.
6. The sigmoid collector is double, located in the sigmoid branch on the inside of the skull, characterized by an S-shaped appearance. In the area of ​​the opening of the great veins, this tank flows into the jugular vein.
7. The cavernous sinus is double and lies on the vault of the cranium away from the sella turcica. They pass through this tank carotid artery and some intracranial ones. The recess has a very intricate structure in the form of interconnected caves, which is why it got its name.
8. The sphenoparietal lacuna is double, refers to the spacious posterior border of a small wedge-shaped bone fragment, in the cleft it connects in this place with the dura mater of the brain.
9. The upper and lower stony recesses are double and lie longitudinally along the upper and lower borders of the triangle of bone tissue in the temporal region.

In some areas, all these cisterns form connections - anastomoses - with the external veins of the skull through connections of vessels. In addition, the sinuses of the TO connect to the diploic arteries, which are located in the spongy structure of the bones of the base of the skull and are included in the superficial vessels of the head. Thus, blood from the veins of the brain flows through the branches of its vessels located on the surface and in the depths into the sinuses of the brain and then into both internal large veins.

Functions

TO key tasks TMO mainly refers to:

• ensuring blood drainage from the vessels of the head and, accordingly, blood circulation;
• protective function - TMF is the densest structure among existing protective layers;
• providing a shock-absorbing effect due to the circulation of cerebrospinal fluid.

Comparison with soft shell

The most basic difference between the dura mater and the soft mater is the presence of double layers, large quantity veins and capillaries in the second. In addition, the pia mater is located closest to the gyri, glia and barbules, separated only by the glial diaphragm. In specific areas, the soft membrane penetrates into the spaces of the ventricles of the brain and forms vascular weaves that synthesize cerebrospinal fluid. Whereas the dura mater has sinuses, and has a slightly different structure and functional tasks.

Dura mater, dura mater, is a shiny, whitish shell made of dense fibrous tissue With big amount elastic fibers.

Its outer rough surface faces inner surface spinal canal and skull bones; with its internal smooth shiny surface, covered with flat epithelioid cells, it is directed towards the arachnoid membrane.

Dura mater of the spinal cord

Dura mater spinalis , forms a wide, cylindrical bag elongated from top to bottom.

The upper border of this shell is located at the level of the foramen magnum, along the inner surface of which, as well as the underlying I cervical vertebra fuses with their periosteum. In addition, it is tightly connected with the integumentary membrane and with the posterior atlanto-occipital membrane, where it is pierced by the vertebral artery. The membrane is attached to the posterior longitudinal ligament of the spinal column by short connective tissue cords.

Sheaths of the spinal cord, meninges medullae spinalis ;

In the downward direction, the dura sac expands somewhat and, having reached the II-III lumbar vertebra, i.e. below the level of the spinal cord, passes into the filament (dura) of the spinal cord, filum terminale externum, which is attached to the periosteum of the coccyx.

The roots, nodes and nerves extending from the spinal cord are enveloped by a hard shell in the form of sheaths, expanding towards the intervertebral foramina and taking part in fixing the shell.

Spinal cord membranes,
meninges medullae spinalis;

view from above.

Dura mater of the spinal cord innervate branches of the meninges of the spinal nerves; supply blood branches of the vertebral arteries and branches of the parietal arteries of the thoracic and abdominal parts aorta; venous blood collects in the vertebral venous plexuses.

Dura mater encephali , is a strong connective tissue formation in which outer and inner plates are distinguished.

The outer plate, lamina externa, has a rough surface, rich in vessels, and is adjacent directly to the bones of the skull, being their internal periosteum. Penetrating into the openings of the skull through which the nerves exit, it envelops them in the form of a vagina.

The hard shell of the brain is weakly connected to the bones of the cranial vault, with the exception of the places where the cranial sutures pass, and at the base of the skull it is firmly fused with the bones.

In children, before fusion of the fontanelles, according to their location, the dura mater of the brain tightly fuses with the membranous skull and is closely connected with the bones of the cranial vault.

Dura mater of the brain
brain, dura mater encephali;

right and top view.

Inner plate, lamina interna, The dura mater of the brain is smooth, shiny and covered with endothelium.

The dura mater of the brain forms processes that are located between the parts of the brain, separating them.

Along the lines of attachment of the processes of the dura mater of the brain, spaces are formed in it, having a prismatic or triangular shape - sinuses of the dura mater , which are collectors through which venous blood from the veins of the brain, eyes, dura mater and cranial bones is collected into the system of internal jugular veins.

These spaces - sinuses - have tightly stretched walls, do not collapse when cut, and there are no valves in them. A number of sinuses open into the cavity emissary veins, through which the sinuses communicate through channels in the bones of the skull with the veins of the scalp.

Dura mater of the brain innervated meningeal branches of the trigeminal and vagus nerves, sympathetic nerves from the periarterial plexuses (middle meningeal artery, vertebral artery, as well as the cavernous plexus), branches of the greater petrosal nerve and ear ganglion; sometimes in the thickness of some nerves there are intra-trunk nerve cells. Most of the nerve branches of the meninges follow the course of the vessels of this membrane, with the exception of the tentorium of the cerebellum, where there are few vessels, unlike other areas of the dura mater of the brain, and where most of nerve branches should be independent of the vessels.

Nerves of the dura mater of the brain :

A-region of the middle cranial fossa:

1 - trigeminal node; 2 - plexus of arcades; 3 - middle meningeal artery; 4 - meningeal branch of the mandibular nerve; 5-middle meningeal nerve; 6 - stony branch of the middle meningeal artery and accompanying nerves; 7 - superior tympanic artery and accompanying nerves.

First branch trigeminal nerve - optic nerve sends trunks to the dura mater of the brain in the region of the anterior cranial fossa, the anterior and posterior parts of the cranial vault, as well as to the falx cerebri, reaching the inferior sagittal sinus, and to the tentorium cerebellum (branch of the tentorium). The second and third branches of the trigeminal nerve, the maxillary nerve and the mandibular nerve, send the middle branch of the meninges to the membrane of the middle cranial fossa, the tentorium cerebellum and the falx cerebri. These branches are also distributed in the walls of nearby venous sinuses.

To the dura mater of the brain in the region of the posterior cranial fossa, up to the tentorium of the cerebellum, and to the walls of the transverse and occipital sinuses, the thin branch of the meninges sends nervus vagus. In addition, the trochlear, glossopharyngeal, accessory and hypoglossal nerves may participate to varying degrees in the innervation of the dura mater of the brain.

Blood supply to the dura mater of the brain branches coming from the maxillary artery (middle meningeal artery); from the vertebral artery (branch to the meninges); from the occipital artery (meningeal branch and mastoid branch); from the ophthalmic artery (from the anterior ethmoidal artery - anterior meningeal artery). Deoxygenated blood collects in nearby sinuses of the dura mater of the brain.

The brain is covered by three membranes, 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 membrane petal 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 exfoliates; the so-called epidural space is preserved between it and the bone. At the base of the skull, the dura mater is tightly fused with the bones, which explains, for example, the appearance of liquorrhea from the nose or ears when bones are fractured in the area of ​​the anterior or middle cranial fossa. 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. 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 cerebri 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), on the sides - on the upper edge of the pyramid of both temporal bone, in front - on the processus clinoidei of the sphenoid bone.

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 cerebelii, 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.

Sinuses of the dura mater.

In the thickness of the processes of the dura mater there are venous sinuses devoid of valves. 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 inferior 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).

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

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

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, nerves pass (counting from top to bottom) - 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 jugular foramen, where it passes into the superior bulb of the internal jugular vein. The projection of the transverse sinus corresponds to the line forming a lung convexity upward and connecting the external occipital protuberance with the superoposterior part 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 confluence of the sagittal sinus does not merge with other sinuses, but passes directly into the right transverse sinus.

(dura mater; synonym pachymeninx) external M. o., consisting of dense fibrous connective tissue, adjacent in the cranial cavity to the inner surface of the bones, and in spinal canal separated from the surface of the vertebrae by loose connective tissue epidural space.

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"dura mater" in books

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