Anatomy and physiology assign an important role to the membranes of the brain (spinal and brain). Special attention is paid to their features, structure and functions, since the functioning of the entire human body depends on them.
What is the meninges?
The medulla is a membranous connective tissue structure that surrounds both the spinal cord and the brain. It could be:
- solid;
- spider;
- soft or vascular.
Each of these species is present both in the brain and in the spinal cord and is a single whole, passing from one brain to another.
Next, we will talk about the dura mater.
Anatomy of the membrane covering the brain
The dura mater of the brain is a formation with a dense consistency, which is located under the inner surface of the skull. Its thickness in the region of the arch varies from 0.7 to 1 mm, and at the base of the cranial bones - from 0.1 to 0.5 mm. In places wherethere are openings, vascular grooves, protrusions and sutures, and also at the base of the skull it fuses with the bones, and in other areas its connection with the bones of the skull is more loose.
In the process of development of pathologies, detachment of the described membrane from the cranial bones can occur, as a result of which a gap is formed between them, which is called the epidural space. In places where it is present, in case of violation of the integrity of the cranial bones, the formation of epidural hematomas occurs.
The walls of the dura mater of the brain are smoother from the inside than from the outside. There, it loosely connects to the arachnoid membrane below it with the help of a multilayer accumulation of specific cells, rare connective tissue filaments, thin vascular stems and nerves, as well as pachyon granulations of the arachnoid membrane. Normally, there is no space or gap between these two shells.
In some places, the dura mater may separate, resulting in the formation of two sheets. Between them there is a gradual formation of the venous sinuses and the trigeminal cavity - the location of the trigeminal node.
Processes extending from the hard shell
Between the brain formations, 4 main processes depart from the hard shell. These include:
Sickle brain. 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, locatedon the ethmoid bone, is the beginning of this process. Further, its convex edge is fastened to the lateral ribs of the furrow located on the superior sagittal sinus. This process of the meninges reaches the occipital protuberance and then passes into the outer surface, which forms the cerebellar tenon
- Sickle of the cerebellum. It originates on the internal occipital protuberance and follows its crest to the posterior edge of the large foramen in the occiput. There he 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.
- The cerebellar basting. This process of the hard shell of the brain stretches over the fossa of the posterior 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 the middle part pulled upwards. Its free edge, which is located in front, has a concave surface, forming a notch notch, which limits its opening. This is the location of the brain stem.
- Saddle diaphragm. This process got its name due to the fact that it is stretched over the Turkish saddle and forms its so-called roof. Below the diaphragm of the saddle is the pituitary gland. In its middle there is a hole through which passes a funnel that holds the pituitary gland.
Anatomy of the meninges of the spinal cord
Thicknessthe dura mater of the spinal cord is smaller than that of the brain. With its help, a sac (dural) is formed, in which the entire spinal cord is located. A thread from a hard shell departs from this bag, leading down, subsequently attached to the coccyx.
There is no fusion between the dura and periosteum, resulting in the formation of an epidural space, which is filled with loose irregular connective tissues and internal venous vertebral plexuses.
With the help of the hard shell, the formation of fibrous sheaths located near the roots of the spinal cord is carried out.
Rigid shell functions
The main function of the dura mater is to protect the brain from mechanical damage. They perform the following role:
- Provides blood circulation and its removal from the vessels of the brain.
- Due to their dense structure, they protect the brain from external influences.
Another function of the dura mater is to create a shock-absorbing effect as a result of CSF 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 developmentbrain. In this case, the hard shell of the brain remains underdeveloped and the formation of defects in the skull itself (windows) is possible. In the spinal cord, developmental pathology can lead to local splitting of the dura mater.
Craniocerebral or spinal cord injury can lead to damage.
Inflammation in the dura mater is called pachymeningitis.
Inflammatory disease in the lining of the brain
Often the cause of the inflammatory process in the dura mater of the brain becomes an infection.
In the practice of doctors, the development of hypertrophic (basal) pachymeningitis or GPM occurs in patients. It is a manifestation of pathology in the described structure. More often this disease affects men at a young or middle age.
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 sickle or cerebellar tenon is located.
In the case of an autoimmune variant of GLM, examination of the cerebrospinal fluid can reveal pleocytosis, elevated proteins, and no microbial growth.
Pathology of the dura mater of the spinal cord
Often develops external pachymeningitis. In the process of its development, inflammation occurs that affects the epidural tissue, after which it spreadsinflammation on the entire surface of the hard shell of the spinal cord.
Diagnosing an ailment is quite difficult. But the incidence of spinal pachymeningitis is higher than the development of pathologies associated with inflammation in the dura mater. To identify it, it is necessary to start from the patient's complaints, anamnesis, as well as laboratory studies of cerebrospinal fluid and blood.
Tumors
Dura mater can be subject to the development of both benign and malignant tumors. So in the described structures or their processes, meningiomas can develop, growing towards the brain and squeezing it.
Malignant tumors in the dura mater most often occur due to metastases, resulting in the formation of single or multiple nodes.
Diagnosis of such a pathology is carried out by examining cerebral or cerebrospinal fluids for the presence of tumor cells.
