The brain is one of the most basic human organs, governing both mental processes and cognitive and emotional capacities as well as the various systems and organs of the body, including the control of vital constants.
It is therefore a fundamental organ and essential to life, being necessary a certain protection against any possible damage which could come from the outside. The skull is an excellent protective barrier, but it is not the only barrier present.
There are a number of membranes called meninges between the skull and the brain. which also serve, among other things, to protect the brain and the nervous system as a whole. One of them is duramater.
The dura mater: the outermost of the meninges
The meninges are a series of three membranes called dura, arachnoid, and piamater that surround and protect the brain. These membranes are located between the skull and the brain, being located one after the other and circulating between them various blood vessels and fluids such as cerebrospinal fluid. Their presence is not only in the brain, which they completely cover, but on top of that, they are present in a large part of the spinal cord.
The outermost of the three this article deals with is duramater. They are the thickest and most resistant meninges, in close contact with the skull. Its rigidity and the various extensions it possesses covering the brain allow it to retain its shape and internal consistency. It also contains a large part of the veins that collect blood used by the brain and return it to the heart. The dura mater covers most of the nervous system with great precision, stretching from the brain to the sacral vertebrae of the spinal cord.
The dura mater and the rest of the meninges contain and are connected by different nerve fibers, possessing several pressure and pain receptors. In the dura itself, the presence of the trigeminal and vagus nerves, as well as the first three spinal nerves, stands out. It is, in short, a layer of the meninges which acts as a “bridge” between the central nervous system and the elements of the body which lie beyond.
Anatomical structure of the dura
If we analyze the dura mater and its composition, we can observe how this meninge possesses and it is mainly composed of two large layers, the periosteal layer and the meningeal layer, From the last four large partitions which divide the cranial cavity into different parts or cells.
1. Periodic coverage
The first of the dura mater layers is the so-called periosteal or endosteal layer, that is, the part of the meninges attached to the skull. It is in this layer that most of the blood vessels that supply the brain are located. It is only found at the cranial level, not being present in the spinal cord.
2. Meningeal cover
Later, the meningeal layer can be found, which is very strong and has a high collagen content. It is from this layer that a series of partitions extend, which are the ones that help shape the brain. maintain the boundaries between the different structures.
These septa of the dura mater, which divide the cranial cavity into different cells, are as follows.
2.1. Brain sickle
The sickle name of this partition is due to the fact that it cuts or divides the cerebral fossa into two parts. It is located in the middle of the skull, vertically.
2.2. Brain shop
This septum of the dura separates the occipital lobes and the cerebellum. Protects the midbrain. It also delimits and protects the trigeminal nerve.
2.3. Cerebellar sickle
Like the sickle in the brain, this septum maintains one of the brain structures divided into two halves. In this case, this partition keeps the two cerebellar hemispheres separate.
2.4. Pituitary store
It is a partition that surrounds the Turkish chair, Part of the skull where the pituitary gland is located, to which it protects.
The existence of the dura mater is a great advantage for human survival. The main functions of this membrane, although they have been seen above, are as follows.
1. Protects the brain and spinal cord
The main function of the dura and other meninges is to protect the nervous system. This protection is given both at the biological level, because it acts as a filter that makes it difficult for the entry of external harmful agents, and at the physical level, because between the presence of the skull, the membrane itself and the liquid cerebrospinal is difficult. that beatings can affect and injure the brain.
2. It helps maintain the shape of the brain
The division into cells of the cranial cavity, which occurs through the partitions of the dura mater, it helps maintain the structure of different locations and parts of the brain, As well as its general shape.
3. Prevents movement of brain mass
The presence of the meninges keeps the brain in place, Limit the displacement which could occur before the simple movement of the body.
4. irrigate the brain
In the dura there is a large number of blood vessels, Especially those which are responsible for returning to the heart the blood from which the brain has already consumed nutrients, that is to say the veins. Thus, this layer of the meninges plays an important role in the proper functioning of a large part of the central nervous system and can drain excess blood.
However, this function of the dura also exposes it to risks in the form of pathologies, such as very dangerous aneurysms, meningitis-type infections or even ischemia.
5. Perception of pain and brain tension
The dura and the rest of the meninges are innervated by different nerves, containing a large number of receptors. These receptors are a physiological detection mechanism for brain problems. They allow for example to perceive the pain associated with the pressure of the brain against the skull, and are even the main culprits that suffer from headaches.
This function is especially vital for survival, because the brain itself does not have receptors that can warn of the onset of internal disease. In other words, without the presence of meninges, we would not be able to detect headaches. warn of problems and give us time to react shortly before very delicate areas of the nervous system are damaged.
- Kandel, ER; Schwartz, JH; Jessell, TM (2001). Principles of neuroscience. Madrid: McGraw Hill
- Martinez, F .; Tomorrow, G .; Panuncio, A. and Laza, S. (2008). Anatomo-clinical examination of the meninges and intracranial spaces with particular reference to chronic subdural hematoma. Mexican Journal of Neuroscience: 9 (1): 17-60.