The spinal cord is covered with three membranes: external - hard, middle - arachnoid and internal - vascular (Fig. 11.14).

hard shell The spinal cord consists of dense, fibrous connective tissue and starts from the edges of the foramen magnum in the form of a bag, which descends to the level of the 2nd sacral vertebra, and then goes as part of the final thread, forming its outer layer, to the level of the 2nd coccygeal vertebra. The dura mater of the spinal cord surrounds the outside of the spinal cord in the form of a long sac. It is not adjacent to the periosteum of the spinal canal. Between it and the periosteum is the epidural space, in which fatty tissue and the venous plexus are located.

11.14. Sheaths of the spinal cord.

Arachnoid The spinal cord is a thin and transparent, avascular, connective tissue sheet located under the dura mater and separated from it by the subdural space.

choroid the spinal cord is tightly attached to the substance of the spinal cord. It is made up of loose connective tissue rich in blood vessels that supply blood to the spinal cord.

There are three spaces between the membranes of the spinal cord: 1) supra-hard (epidural); 2) confirmed (subdural); 3) subarachnoid.

Between the arachnoid and soft shells is the subarachnoid (subarachnoid) space containing cerebrospinal fluid. This space is especially wide at the bottom, in the region of the cauda equina. The cerebrospinal fluid that fills it communicates with the fluid of the subarachnoid spaces of the brain and its ventricles. On the sides of the spinal cord in this space lies the dentate ligament, which strengthens the spinal cord in its position.

Superhard space(epidural) is located between the dura mater and the periosteum of the spinal canal. It is filled with fatty tissue, lymphatic vessels and venous plexuses, which collect venous blood from the spinal cord, its membranes and the spinal column.

Confirmed space(subdural) is a narrow gap between the hard shell and the arachnoid.

A variety of movements, even very abrupt ones (jumps, somersaults, etc.), do not impair the reliability of the spinal cord, since it is well fixed. At the top, the spinal cord is connected to the brain, and at the bottom, its terminal thread fuses with the periosteum of the coccygeal vertebrae.

In the region of the subarachnoid space, there are well-developed ligaments: the dentate ligament and the posterior subarachnoid septum. dentate ligament located in the frontal plane of the body, starting both to the right and to the left of the lateral surfaces of the spinal cord, covered with a pia mater. The outer edge of the ligament is divided into teeth that reach the arachnoid and are attached to the dura mater so that the posterior, sensory, roots pass behind the dentate ligament, and the anterior, motor roots, in front. Posterior subarachnoid septum located in the sagittal plane of the body and runs from the posterior median sulcus, connecting the pia mater of the spinal cord with the arachnoid.

For the fixation of the spinal cord, the formation of a supra-solid space (fatty tissue, venous plexuses), which act as an elastic pad, and the cerebrospinal fluid, in which the spinal cord is immersed, are also important.

All factors that fix the spinal cord do not prevent it from following the movements of the spinal column, which are very significant in certain positions of the body (gymnastic bridge, wrestling bridge, etc.) from the continents.

The spinal cord is dressed in three connective tissue membranes, meninges. These shells are as follows, if you go from the surface inward: hard shell, dura mater; arachnoid, arachnoidea, and soft shell, pia mater. Cranially, all 3 shells continue into the same shells of the brain.

The hard shell of the spinal cord, dura mater spinalis, covers the outside of the spinal cord in the form of a bag. It does not adhere closely to the walls of the spinal canal, which are covered with periosteum. The latter is also called the outer sheet of the hard shell. Between the periosteum and the hard shell is the epidural space, cavitas epiduralis. It contains fatty tissue and venous plexuses, plexus vendsi vertebrales interni, into which venous blood flows from the spinal cord and vertebrae.

Cranially, the hard shell fuses with the edges of the foramen magnum of the occipital bone, and caudally ends at the level of II-III sacral vertebrae, tapering in the form of a thread, filum diirae matris spinalis, which is attached to the coccyx.

The arachnoid membrane of the spinal cord, arachnoidea spinalis, in the form of thin crossbars of the subdural space, spatium subdurale. Between the arachnoid and the pia mater directly covering the spinal cord is the subarachnoid space, cavitas subarachnoidalis, in which the brain and nerve roots lie freely, surrounded by a large amount of cerebrospinal fluid, liquor cerebrospinalis. Cerebrospinal fluid is taken from this space for analysis. This space is especially wide in the lower part of the arachnoid sac, where it surrounds the cauda equina of the spinal cord (cisterna terminalis). The fluid filling the subarachnoid space is in continuous communication with the fluid of the subarachnoid spaces and ventricles of the brain.

Between the arachnoid and the pia mater covering the spinal cord in the cervical region behind, along the midline, a septum, septum cervie ale intermedium, is formed. In addition, on the sides of the spinal cord in the frontal plane there is a dentate ligament, ligamentum denticulatum, consisting of 19-23 teeth passing between the anterior and posterior roots. The dentate ligaments serve to hold the brain in place, preventing it from stretching out in length. Through both ligg. denticulatae subarachnoid space is divided into anterior and posterior sections.

The soft shell of the spinal cord, pia mater spinalis, covered from the surface with endothelium, directly envelops the spinal cord and contains vessels between its two sheets, together with which it enters its furrows and the medulla, forming perivascular spaces around the vessels.

Conclusion

The spinal cord is a section of the central nervous system of vertebrates and humans, located in the spinal canal; more than other parts of the central nervous system retained the features of the primitive brain tube of chordates. The spinal cord has the form of a cylindrical cord with an internal cavity (spinal canal); it is covered with three meninges: soft, or vascular (internal), arachnoid (middle) and hard (outer), and is held in a constant position with the help of ligaments going from the membranes to the inner wall of the bone canal. The space between the soft and arachnoid membranes (subarachnoid) and the brain itself, as well as the spinal canal, are filled with cerebrospinal fluid. The anterior (upper) end of the spinal cord passes into the medulla oblongata, the posterior (lower) end into the terminal thread.

The spinal cord is conditionally divided into segments according to the number of vertebrae. A person has 31 segments: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 1 coccygeal. A group of nerve fibers departs from each segment - radicular threads, which, when combined, form the spinal roots. Each pair of roots corresponds to one of the vertebrae and leaves the spinal canal through the opening between them. The posterior spinal roots carry sensory (afferent) nerve fibers, through which impulses from the receptors of the skin, muscles, tendons, joints, and internal organs are transmitted to the spinal cord. The anterior roots contain motor (efferent) nerve fibers, along which impulses from the motor or sympathetic cells of the spinal cord are transmitted to the periphery (to skeletal muscles, vascular smooth muscles and internal organs). The posterior and anterior roots are connected before entering the intervertebral foramen, forming mixed nerve trunks at the exit from the spine.

The spinal cord consists of two symmetrical halves connected by a narrow bridge; nerve cells and their short processes form gray matter around the spinal canal. The nerve fibers that make up the ascending and descending pathways form white matter along the edges of the gray matter. Outgrowths of gray matter (anterior, posterior and lateral horns) white matter is divided into three parts - anterior, posterior and lateral cords, the boundaries between which are the exit points of the anterior and posterior spinal roots.

The activity of the spinal cord is reflex in nature. Reflexes arise under the influence of afferent signals entering the spinal cord from receptors that are the beginning of the reflex arc, as well as under the influence of signals going first to the brain, and then descending into the spinal cord along descending pathways. The most complex reflex reactions of the spinal cord are controlled by various centers of the brain. In this case, the spinal cord serves not only as a link in the transmission of signals coming from the brain to the executive organs: these signals are processed by intercalary neurons and combined with signals coming at the same time from peripheral receptors.

The spinal cord is covered on the outside with membranes that are a continuation of the membranes of the brain. They perform the functions of protection against mechanical damage, provide nutrition for neurons, control water metabolism and metabolism of nervous tissue. Between the membranes circulates cerebrospinal fluid, which is responsible for metabolism.

The spinal cord and brain are parts of the central nervous system that responds and controls all the processes that occur in the body - from mental to physiological. The functions of the brain are more extensive. The spinal cord is responsible for motor activity, touch, sensitivity of the hands and feet. The membranes of the spinal cord perform certain tasks and ensure coordinated work to provide nutrition and remove metabolic products from the brain tissues.

The structure of the spinal cord and surrounding tissues

If you carefully study the structure of the spine, it becomes clear that the gray matter is securely hidden first behind the mobile vertebrae, then behind the membranes, of which there are three, followed by the white matter of the spinal cord, which ensures the conduction of ascending and descending impulses. As you climb up the spinal column, the amount of white matter increases, as more controlled areas appear - arms, neck.

White matter is axons (nerve cells) covered with a myelin sheath.

The gray matter provides a connection between the internal organs and the brain with the help of white matter. Responsible for memory processes, vision, emotional status. Gray matter neurons are not protected by myelin sheath and are very vulnerable.

In order to simultaneously nourish the neurons of the gray matter and protect it from damage and infection, nature has created several obstacles in the form of spinal membranes. The brain and spinal cord have identical protection: the membranes of the spinal cord are a continuation of the membranes of the brain. To understand how the spinal canal works, it is necessary to carry out a morphofunctional characteristic of each of its individual parts.

Hard Shell Functions

The dura mater is located just behind the walls of the spinal canal. It is the most dense, consists of connective tissue. On the outside it has a rough structure, and the smooth side is turned inward. The rough layer provides a tight closure with the vertebral bones and holds the soft tissues in the spinal column. The smooth endothelial layer of the dura mater of the spinal cord is the most important component. Its functions include:

• production of hormones - thrombin and fibrin;
• exchange of tissue and lymph fluid;
• blood pressure control;
• anti-inflammatory and immunomodulatory.

The connective tissue during the development of the embryo comes from the mesenchyme - the cells from which the vessels, muscles, and skin subsequently develop.

The structure of the outer shell of the spinal cord is due to the necessary degree of protection of the gray and white matter: the higher - the thicker and denser. At the top, it fuses with the occipital bone, and in the coccyx region it becomes thinner to several layers of cells and looks like a thread.

From the same type of connective tissue, a protection for the spinal nerves is formed, which is attached to the bones and securely fixes the central canal. There are several types of ligaments by which the external connective tissue is fastened to the periosteum: these are lateral, anterior, dorsal connecting elements. If it is necessary to extract the hard shell from the bones of the spine - a surgical operation - these ligaments (or cords) present a problem due to their structure for the surgeon.

Arachnoid

The layout of the shells is described from outer to inner. The arachnoid of the spinal cord is located behind the hard. Through a small space, it adjoins the endothelium from the inside and is also covered with endothelial cells. Appears to be translucent. In the arachnoid there is a huge number of glial cells that help generate nerve impulses, participate in the metabolic processes of neurons, release biologically active substances, and perform a supporting function.

Controversial for physicians is the question of the innervation of the arachnoid film. It has no blood vessels. Also, some scientists consider the film as part of the soft shell, since at the level of the 11th vertebra they merge into one.

The median membrane of the spinal cord is called the arachnoid, as it has a very thin structure in the form of a web. Contains fibroblasts - cells that produce extracellular matrix. In turn, it provides transportation of nutrients and chemicals. With the help of the arachnoid membrane, the movement of cerebrospinal fluid into the venous blood occurs.

Granulations of the middle membrane of the spinal cord are villi that penetrate into the outer hard shell and exchange cerebrospinal fluid through the venous sinuses.

Inner shell

The soft shell of the spinal cord is connected to the hard shell with the help of ligaments. With a wider area, the ligament is adjacent to the soft shell, and with a narrower area, to the outer shell. Thus, the fastening and fixation of the three membranes of the spinal cord occurs.

The anatomy of the soft layer is more complex. This is a loose tissue in which there are blood vessels that deliver nutrition to neurons. Due to the large number of capillaries, the color of the tissue is pink. The pia mater completely surrounds the spinal cord and is denser in structure than similar brain tissue. The shell is so tightly attached to the white matter that at the slightest dissection it appears from the incision.

It is noteworthy that only humans and other mammals have such a structure.

This layer is well washed by the blood and therefore performs a protective function, since the blood contains a large number of leukocytes and other cells responsible for human immunity. This is extremely important, since the entry of microbes or bacteria into the spinal cord can cause intoxication, poisoning and death of neurons. In such a situation, you can lose the sensitivity of certain parts of the body, for which dead nerve cells were responsible.

The soft shell has a two-layer structure. The inner layer is the same glial cells that are in direct contact with the spinal cord and provide its nutrition and removal of decay products, and also participate in the transmission of nerve impulses.

Spaces between the membranes of the spinal cord

3 shells are not in close contact with each other. Between them there are spaces that have their own functions and names.

epidural the space is between the bones of the spine and the hard shell. filled with adipose tissue. This is a kind of protection against lack of nutrition. In emergency situations, fat can become a source of nutrition for neurons, which will allow the nervous system to function and control the processes in the body.

The friability of adipose tissue is a shock absorber, which, under mechanical action, reduces the load on the deep layers of the spinal cord - white and gray matter, preventing their deformation. The membranes of the spinal cord and the spaces between them are a buffer through which the communication of the upper and deep layers of the tissue occurs.

Subdural the space is located between the hard and arachnoid (arachnoid) membrane. It is filled with cerebrospinal fluid. This is the most frequently changing environment, the volume of which is approximately 150 - 250 ml in an adult. The fluid is produced by the body and is updated 4 times a day. In just a day, the brain produces up to 700 ml of cerebrospinal fluid (CSF).

Liquor performs protective and trophic functions.

1. Under mechanical impact - shock, fall, retains pressure and prevents deformation of soft tissues, even with fractures and cracks in the bones of the spine.
2. The composition of the liquor contains nutrients - proteins, minerals.
3. Leukocytes and lymphocytes in the cerebrospinal fluid suppress the development of infection near the central nervous system by absorbing bacteria and microorganisms.

Liquor is an important fluid that doctors use to determine if a person has had a stroke or brain damage that disrupts the blood-brain barrier. In this case, erythrocytes appear in the liquid, which should not normally be.

The composition of cerebrospinal fluid varies depending on the work of other human organs and systems. For example, in case of violations in the digestive system, the liquid becomes more viscous, as a result of which the flow is difficult, and painful sensations appear, mainly headaches.

Decreased oxygen levels also impair the functioning of the nervous system. First, the composition of the blood and intercellular fluid changes, then the process is transferred to the cerebrospinal fluid.

Dehydration is a big problem for the body. First of all, the central nervous system suffers, which, under difficult conditions of the internal environment, is not able to control the work of other organs.

The subarachnoid space of the spinal cord (in other words, the subarachnoid space) is located between the pia mater and the arachnoid. Here is the largest amount of liquor. This is due to the need to ensure the greatest safety of some parts of the central nervous system. For example - the trunk, cerebellum or medulla oblongata. There is especially a lot of cerebrospinal fluid in the region of the trunk, since there are all the vital departments that are responsible for reflexes and breathing.

In the presence of a sufficient amount of liquid, mechanical external influences on the area of ​​the brain or spine reach them to a much lesser extent, since the liquid compensates and reduces the impact from the outside.

In the arachnoid space, fluid circulates in various directions. The speed depends on the frequency of movements, breathing, that is, it is directly related to the work of the cardiovascular system. Therefore, it is important to observe the regime of physical activity, walking, proper nutrition and drinking water.

Cerebrospinal fluid exchange

Liquor through the venous sinuses enters the circulatory system and is then sent for cleaning. The system that produces the liquid protects it from the possible ingress of toxic substances from the blood, and therefore selectively passes elements from the blood into the cerebrospinal fluid.

The shells and intershell spaces of the spinal cord are washed by a closed system of cerebrospinal fluid, therefore, under normal conditions, they ensure the stable operation of the central nervous system.

Various pathological processes that begin in any part of the central nervous system can spread to neighboring ones. The reason for this is the continuous circulation of cerebrospinal fluid and the transfer of infection to all parts of the brain and spinal cord. Not only infectious, but also degenerative and metabolic disorders affect the entire central nervous system.

Analysis of the cerebrospinal fluid is central to determining the degree of tissue damage. The state of the cerebrospinal fluid allows you to predict the course of diseases and monitor the effectiveness of treatment.

Excess CO2, nitric and lactic acids are removed into the bloodstream so as not to create a toxic effect on nerve cells. We can say that the liquor has a strictly constant composition and maintains this constancy with the help of the body's reactions to the appearance of an irritant. A vicious circle occurs: the body tries to please the nervous system, maintaining balance, and the nervous system, with the help of well-adjusted reactions, helps the body maintain this balance. This process is called homeostasis. It is one of the conditions for human survival in the external environment.

Connection between shells

The connection of the membranes of the spinal cord can be traced from the earliest moment of formation - at the stage of embryonic development. At the age of 4 weeks, the embryo already has the rudiments of the central nervous system, in which various tissues of the body are formed from just a few types of cells. In the case of the nervous system, this is the mesenchyme, which gives rise to the connective tissue that makes up the membranes of the spinal cord.

In the formed organism, some shells penetrate one another, which ensures the metabolism and the performance of general functions to protect the spinal cord from external influences.

The spinal cord and brain are covered by three membranes:

outdoor - hard shell (dura mater);

Middle shell - cobweb (arachnoidea);

- inner shell - soft (pia mater).

The membranes of the spinal cord in the region of the foramen magnum continue into the membranes of the same name of the brain.

Directly to the outer surface of the brain, spinal and brain, is adjacent soft (vascular) membrane, which goes into all the cracks and furrows. The soft shell is very thin, formed by loose connective tissue rich in elastic fibers and blood vessels. Connective tissue fibers depart from it, which, together with blood vessels, penetrate the substance of the brain.

Outside of the choroid is located arachnoid . Between the pia mater and the arachnoid, is subarachnoid (subarachnoid) space, filled with liquor -120-140 ml. In the lower part of the spinal canal in the subarachnoid space, the roots of the lower (sacral) spinal nerves freely float and form the so-called "ponytail". In the cranial cavity above large fissures and furrows, the subarachnoid space is wide and forms receptacles - tanks.

The largest tanks cerebellar, lying between the cerebellum and the medulla oblongata cistern of lateral fossa- located in the area of ​​​​the furrow of the same name, cistern of optic chiasm located anterior to the optic chiasm interpeduncular cistern located between the legs of the brain. The subarachnoid spaces of the brain and spinal cord communicate with each other at the junction of the spinal cord with the brain.

Drains into subarachnoid space cerebrospinal fluid, formed in the ventricles of the brain. The lateral, third and fourth ventricles of the brain contain vascular plexus, forming liquor. They consist of loose fibrous connective tissue with a large number of blood capillaries.

From the lateral ventricles through the interventricular openings, the fluid flows into the third ventricle, from the third through the aqueduct of the brain - into the fourth, and from the fourth through three openings (lateral and median) - into the cerebellar-cerebral cistern of the subarachnoid space. The outflow of cerebrospinal fluid from the subarachnoid space into the blood is carried out through protrusions - arachnoid granulation penetrating into the lumen of the sinuses of the hard shell of the brain, as well as into the blood capillaries at the point of exit of the roots of the cranial and spinal nerves from the cranial cavity and from the spinal canal. Thanks to this mechanism, CSF is constantly formed in the ventricles and absorbed into the blood at the same rate.

Outside of the arachnoid is hard shell of the brain , which is made up of dense fibrous connective tissue. In the spinal canal, the dura mater of the spinal cord is a long sac containing the spinal cord with spinal nerve roots, spinal ganglia, pia mater, arachnoid, and cerebrospinal fluid. The outer surface of the dura mater of the spinal cord is separated from the periosteum that lines the spinal canal from the inside epidural space filled with adipose tissue and venous plexus. The hard shell of the spinal cord at the top passes into the hard shell of the brain.

The dura mater of the brain fuses with the periosteum, so it directly covers the inner surface of the bones of the skull. Between the dura mater and the arachnoid there is a narrow subdural space containing a small amount of liquid.

In some areas, the dura mater of the brain forms processes that consist of two sheets and deeply bulge into the cracks that separate parts of the brain from each other. In places where the processes originate, the leaves split, forming triangular channels - sinuses of the dura mater. Venous blood flows into the sinuses from the brain through the veins, which then enters the internal jugular veins.

The largest process of the dura mater is sickle of the brain. The sickle separates the cerebral hemispheres from each other. At the base of the crescent of the brain there is a splitting of its leaves - superior sagittal sinus. In the thickness of the free lower edge of the sickle is inferior sagittal sinus.

Another large branch cerebellum separates the occipital lobes of the hemispheres from the cerebellum. The tentorium of the cerebellum is attached in front to the upper edges of the temporal bones, and behind - to the occipital bone. Along the line of attachment to the occipital bone, the cerebellar mantle is formed between its leaves. transverse sinus, which continues on the sides into a double sigmoid sinus. On each side, the sigmoid sinus passes into the internal jugular vein.

Between the hemispheres of the cerebellum is falx cerebellum, attached behind to the internal occipital crest. Along the line of attachment to the occipital bone of the sickle of the cerebellum in its splitting is occipital sinus.

Above the pituitary gland forms a hard shell Turkish saddle diaphragm which separates the pituitary fossa from the cranial cavity.

On the sides of the Turkish saddle is located cavernous sinus. Through this sinus passes the internal carotid artery, as well as the oculomotor, trochlear and abducens cranial nerves and the ophthalmic branch of the trigeminal nerve,

Both cavernous sinuses are interconnected transverse intercavernous sinuses. Paired upper and inferior petrosal sinuses, lying along the edges of the pyramid of the temporal bone of the same name, they are connected in front with the corresponding cavernous sinus, and behind and laterally with transverse and sigmoid sinuses.

On each side, the sigmoid sinus passes into the internal jugular vein.

Cerebrospinal fluid (CSF)

A biological fluid necessary for the proper functioning of brain tissue.
The physiological significance of liquor:
1.mechanical protection of the brain;
2. excretory, i.e. removes metabolic products of nerve cells;
3. transport, transports various substances, including oxygen, hormones and other biologically active substances;
4. stabilization of brain tissue: maintains a certain concentration of cations, anions and pH, which ensures normal excitability of neurons;
5.performs the function of a specific protective immunobiological barrier.

Physico-chemical properties of liquor
Relative density. The specific gravity of the cerebrospinal fluid is normally

1, 004 - 1, 006. An increase in this indicator is observed in meningitis, uremia, diabetes mellitus, etc., and a decrease in hydrocephalus.
Transparency. Normally, cerebrospinal fluid is colorless, transparent, like distilled water. CSF turbidity depends on a significant increase in the number of cellular elements (erythrocytes, leukocytes, tissue cellular elements), bacteria, fungi and an increase in protein content.
Fibrin (fibrinous) film. Normally, CSF contains virtually no fibrinogen. Its appearance in the cerebrospinal fluid is due to diseases of the central nervous system that cause a violation of the blood-brain barrier. The formation of a fibrinous film is observed in purulent and serous meningitis, tumors of the central nervous system, cerebral hemorrhage, etc.
Color. Normally, cerebrospinal fluid is colorless. The appearance of color usually indicates a pathological process in the central nervous system. However, a grayish or grayish-pink color of the cerebrospinal fluid may be due to an unsuccessful puncture or subarachnoid hemorrhage.
Erythrocytarchia. Normally, erythrocytes in the cerebrospinal fluid are not detected.
The presence of blood in the CSF can be detected macro- and microscopically. There are travel erythrocytarchia (artifact) and true erythrocytarchia.
Travel erythrocytarchia caused by the ingress of blood into the cerebrospinal fluid when injured during the puncture of blood vessels.
True erythrocytarchia occurs with hemorrhages in the cerebrospinal fluid spaces due to rupture of blood vessels in hemorrhagic stroke, brain tumors, craniocerebral injuries.
Bilirubinarchia (xanthochromia)- the presence of bilirubin and other blood breakdown products in the cerebrospinal fluid.
Normally, bilirubin is not detected in the cerebrospinal fluid.
Distinguish:
1.Hemorrhagic bilirubinarchy caused by the ingress of blood into the cerebrospinal fluid spaces, the decay of which leads to the coloring of the cerebrospinal fluid in pink, and then in orange, yellow.
It is observed in: hemorrhagic stroke, traumatic brain injury, rupture of an aneurysm of a cerebral vessel.
The determination of blood and bilirubin in the CSF allows you to diagnose the time of bleeding into the CSF spaces, its cessation and the gradual release of the CSF from blood decay products.
2.congestive bilirubinarchy- this is the result of a slow blood flow in the vessels of the brain, when, due to an increase in the permeability of the walls of the vessels, the blood plasma enters the cerebrospinal fluid.
This is observed with: tumors of the central nervous system, with meningitis, arachnoiditis.
pH. This is one of the relatively stable indicators of cerebrospinal fluid.
The normal pH of CSF is 7.4 - 7.6.
The change in pH in the cerebrospinal fluid affects the cerebral circulation and consciousness.
Primary CSF acidosis manifests itself in diseases of the nervous system: severe cerebral hemorrhage, traumatic brain injury, cerebral infarction, purulent meningitis, status epilepticus, brain metastases, etc.
PROTEINARCHY(total protein) - the presence of protein in the cerebrospinal fluid.
Normally, the protein content in the cerebrospinal fluid is 0.15 - 0.35 g / l.
Hyperproteinarchia - an increase in the protein content in the cerebrospinal fluid, serves as an indicator of the pathological process. It is observed in: inflammation, tumors, brain injuries, subarachnoid bleeding.
GLYCOARCHY- the presence of glucose in the cerebrospinal fluid.
Normally, in the cerebrospinal fluid, the glucose level is: 4, 10 - 4, 17 mmol / l.
The level of glucose in the CSF is one of the most important indicators of the function of the blood-brain barrier.
Hypoglycoarchia - a decrease in the level of glucose in the cerebrospinal fluid. It is observed in: bacterial and fungal meningitis, tumors of the meninges.
Hyperglycoarchia - an increase in the level of glucose in the cerebrospinal fluid, is rare. Observed with: hyperglycemia, with brain injury.
Microscopic examination of cerebrospinal fluid.
Cytological examination of the cerebrospinal fluid is performed in order to determine cytosis - the total number of cellular elements in 1 µl of cerebrospinal fluid, followed by differentiation of cellular elements (liquor formula).
Normally, there are practically no cellular elements in the cerebrospinal fluid: the content of cells is 0 - 8 * 10 6 /l.
An increase in the number of cells ( pleocytosis ) in the cerebrospinal fluid is considered as a sign of damage to the central nervous system.
After counting the total number of cells, cell differentiation is carried out. The following cells may be present in the cerebrospinal fluid:
Lymphocytes. Their number increases with tumors of the central nervous system. Lymphocytes are found in chronic inflammatory processes in the membranes (tuberculous meningitis, cysticercosis arachnoiditis).
plasma cells. Plasma cells are found only in pathological cases with long-term inflammatory processes in the brain and membranes, with encephalitis, tuberculous meningitis, cysticercosis arachnoiditis and other diseases, in the postoperative period, with sluggish wound healing.
tissue monocytes. They are found after surgery on the central nervous system, with long-term ongoing inflammatory processes in the membranes. The presence of tissue monocytes indicates an active tissue reaction and normal wound healing.
macrophages. Macrophages are not found in normal cerebrospinal fluid. The presence of macrophages in normal cytosis is observed after bleeding or during an inflammatory process. As a rule, they occur in the postoperative period.

Neutrophils. The presence of neutrophils in the CSF, even in minimal amounts, indicates either a former or an existing inflammatory reaction.

Eosinophils occur with subarachnoid hemorrhages, meningitis, tuberculous and syphilitic brain tumors.
epithelial cells. Epithelial cells limiting the subarachnoid space are rare. They are found in neoplasms, sometimes in inflammatory processes.

The membranes of the brain and spinal cord are represented by hard, soft and arachnoid, having the Latin names dura mater, pia mater et arachnoidea encephali. The purpose of these anatomical structures is to protect the conductive tissue of both the brain and spinal cord, as well as to form a volumetric space in which cerebrospinal fluid and cerebrospinal fluid circulate.

Dura mater

This part of the protective structures of the brain is represented by connective tissue, dense in consistency, fibrous structure. It has two surfaces - external and internal. The outer one is well supplied with blood, includes a large number of vessels, and is connected to the bones of the skull. This surface functions as a periosteum on the inner surface of the cranial bones.

Dura mater (dura mater) has several parts that penetrate the cranial cavity. These processes are duplications (folds) of connective tissue.

The following formations are distinguished:

• falx cerebellum - located in the space bounded by the halves of the cerebellum on the right and left, the Latin name is falx cerebelli:
• the crescent of the brain - like the first is located in the interhemispheric space of the brain, the Latin name is falx cerebri;
• the tentorium of the cerebellum is located above the posterior cranial fossa in a horizontal plane between the temporal bone and the transverse occipital groove, it delimits the upper surface of the cerebellar hemispheres and the occipital cerebral lobes;
• diaphragm of the Turkish saddle - located above the Turkish saddle, forming its ceiling (operculum).

Layered structure of the meninges

The space between the processes and sheets of the hard shell of the brain is called the sinuses, the purpose of which is to create space for venous blood from the vessels of the brain, the Latin name is sinus dures matris.

There are the following sinuses:

• superior sagittal sinus - located in the region of the large crescent process on the protruding side of its upper edge. Blood through this cavity enters the transverse sinus (transversus);
• the lower sagittal sinus, which is located in the same area, but at the lower edge of the falciform process, flows into the direct sinus (rectus);
• transverse sinus - located in the transverse groove of the occipital bone, passes to the sinus sigmoideus, passing in the region of the parietal bone, near the mastoid angle;
• the straight sinus is located at the junction of the cerebellum and the large falciform fold, the blood from it enters the sinus transversus as well as in the case of the large transverse sinus;
• cavernous sinus - located on the right and left near the Turkish saddle, has the shape of a triangle in a transverse section. In its walls are the branches of the cranial nerves: in the upper - the oculomotor and trochlear, in the lateral - the ophthalmic nerve. The abducens nerve is located between the ophthalmic and trochlear. As for the blood vessels of this area, inside the sinus is the internal carotid artery, along with the carotid plexus, washed by venous blood. The upper branch of the ophthalmic vein flows into this cavity. There are messages between the right and left cavernous sinus, called the anterior and posterior intercavernous sinuses;
• the superior stony sinus is a continuation of the previously described sinus, located in the region of the temporal bone (at the upper edge of its pyramid), being the connection between the transverse and cavernous sinuses;
• lower petrosal sinus - located in the lower petrosal groove, along the edges of it are the pyramid of the temporal bone and the occipital bone. Communicates with sinus cavernosus. In this area, by merging the transverse connecting branches of the veins, the basilar plexus of veins is formed;
• occipital sinus - formed in the region of the internal occipital crest (protrusion) from the sinus transversus. This sinus is divided into two parts, covering the edges of the foramen magnum on both sides and flowing into the sigmoid sinus. At the junction of these sinuses there is a venous plexus called the confluens sinuum (the fusion of the sinuses).

Arachnoid

Deeper than the hard shell of the brain is the arachnoid, which completely covers the structures of the central nervous system. It is covered with endothelial tissue and is connected to hard and soft supra- and subarachnoid septa formed by connective tissue. Together with the solid, it forms the subdural space, in which a small volume of cerebrospinal fluid (cerebrospinal fluid, cerebrospinal fluid) circulates.

Schematic representation of the meninges of the spinal cord

On the outer surface of the arachnoid in some places there are outgrowths represented by rounded pink bodies - granulations. They penetrate into the solid and contribute to the outflow of cerebrospinal fluid through filtration into the venous system of the skull. The surface of the membrane adjacent to the brain tissue is connected by thin strands to the soft one, between them a space is formed, called the subarachnoid, or subarachnoid.

soft shell of the brain

This is the shell closest to the medulla, consisting of connective tissue structures, loose in consistency, contains plexuses of blood vessels and nerves. Small arteries passing through it connect with the bloodstream of the brain, separated only by a narrow space from the upper surface of the brain. This space is called supracerebral, or subpial.

The pia mater is separated from the subarachnoid space by a perivascular space with many blood vessels. In the transverse purposes of the encephalon and cerebellum, it is located between the areas limiting them, as a result of which the spaces of the third and fourth ventricles are closed and connected to the choroid plexuses.

Meninges of the spinal cord

The spinal cord is similarly surrounded by three layers of connective tissue membranes. The hard shell of the spinal cord differs from that adjacent to the encephalon in that it does not adhere tightly to the edges of the spinal canal, which is covered with its own periosteum. The space that forms between these membranes is called the epidural, it contains the venous plexus and fatty tissue. The hard shell penetrates with its processes into the intervertebral foramina, enveloping the roots of the spinal nerves.

The spine and adjacent structures

The soft shell of the spinal cord is represented by two layers, the main feature of this formation is that many arteries, veins and nerves pass through it. The medulla is adjacent to this membrane. Between the soft and hard is the arachnoid, represented by a thin sheet of connective tissue.

On the outside, there is a subdural space, which in the lower part passes into the terminal ventricle. In the cavity formed by the sheets of the hard and arachnoid membranes of the central nervous system, cerebrospinal fluid, or cerebrospinal fluid, circulates, which also enters the subarachnoid spaces of the encephalon ventricles.

The spinal structures throughout the brain are adjacent to the dentate ligament, which penetrates between the roots and divides the subarachnoid space into two parts - the anterior and posterior spaces. The back section is divided into two halves by an intermediate cervical septum - into the left and right parts.