Anatomy & Organs

Cerebral ventricles – structure, function & diseases

Hind ventricle

The cavities in the brain that produce the vital cerebrospinal fluid are called cerebral ventricles . The ventricular system of the brain consists of a total of four ventricles that communicate with each other and are connected to the outer cerebrospinal fluid space in the connective tissue layer of the spinal cord . One of the most common complaints associated with the cerebral ventricles is a cystic mass in the third ventricle, which can block CSF drainage and initiate intracranial hypertension .

What are the cerebral ventricles?

Neurology understands the cerebral ventricles to be extensive cavities in the brain that are filled with liquor, i.e. cerebrospinal fluid. The ventricular system is thus a system of cavities that is roughly divided into four ventricles. In addition to the ventricles of the two cerebral hemispheres , there is a third ventricle in the diencephalon , i.e. the diencephalon, and the fourth in the caudally located rhomcephalon.

The individual ventricles differ in their anatomy. They are connected to each other by so-called foramina, i.e. holes, as well as structures such as the aquaeductus mesencephali and are in permanent communication via these connections. The starting point of the ventricular system is the central canal of the neural tube, which has formed the individual ventricles through growth processes. All cerebral ventricles are lined on the inside. This lining is called the ependyma.

This is a special tissue that is traversed by the so-called choroid plexus. The cerebrospinal fluid is located in this network of veins. For this reason, the ventricular system is also referred to as the inner liquor space. This liquor-filled cavity communicates in the area of ​​the fourth ventricle with the outer liquor space, which sits between the arachnoid and the pia mater, i.e. between the meninges and the connective tissue layer in the spinal cord.

Anatomy & Structure

The two ventricles of the cerebrum are made up of anterior horn, middle part, posterior horn and inferior horn. The so-called rostrum corporis callosi forms the anterior horn floor. The anterior wall of the structure, on the other hand, forms the genu corporis callosi. The lateral wall forms the Caput nuclei caudati. The inner walls are formed by the septum pellucidum, while the truncus corporis callosi forms the roof. The stria terminalis together with the lamina affixa plexus choroideus and the so-called crus fornicis form the middle part of the two ventricles.The lateral walls are formed by the corpus nuclei caudati and the inner walls by the septum pellucidum and the crus fornicis. The truncus corporis callosi forms the roof of the ventricles. At the bottom of the posterior horn, the ventricles end with the eminentia collateralis and the trigonum collaterale, while the calcar avis forms the inner boundary and the tapetum the lateral boundary. The floor of the lower horn consists of the alveus hippocampi and the eminentia collateralis.

The choroid plexus forms the inner wall together with the fimbria hippocampi, while the tapetum forms the lateral wall together with the cauda nuclei caudati. The lateral walls of the cornu posterius and the cornu inferius each correspond to the roof of these two structures. The posterior and anterior horns are secondary protuberances and therefore remain entirely free of the choroid plexus. The third ventricle of the diencephalon sits under the fornix and is formed at the floor by portions of the optic chiasm, infundibuli recess, and supraoptic recess, and the midbrain cap.

Der Plexus choroideus ventriculi tertii und die Tela choroidea ventriculi bilden das Dach, während die Commissura anterior, die Columna fornicis, die Lamina terminalis und der Recessus triangularis die vordere Wand ausformen. Die hintere Wand des dritten Ventrikels besteht aus der Commissura posterior, der Commissura habenularum, dem Recessus suprapinealis und dem Recessus pinealis. Der Thalamus bildet zusammen mit der Stria medullaris thalami, dem Adhaesio interthalamica und dem Sulcus hypothalamicus sowie dem Hypothalamus die seitliche Wand.

The fourth ventricle of the rhombencephalon is located in the rhomboid fossa and bounded by the cerebellar cusps, the obex, and the tela choroidea, and the ventriculi quarti, the nodulus, and the fastigium. Unlike the rest, this ventricle has three openings that connect to the outer CSF space and ensure CSF drainage.

Function & Tasks

The most important task of the cerebral ventricular system is the management of the cerebrospinal fluid. The liquor serves as protection against impact, friction and pressure. Apart from that, the cerebrospinal fluid nourishes the entire brain as well as the spinal cord with glucose. It also removes metabolic products from the brain and serves to protect the brain system from heat.

The capillary networks, i.e. the plexus choroidei of the vnetricle system, form the vital cerebrospinal fluid via filtration and secretion processes from blood plasma . Overall, the ventricular system produces between 500 and 700 milliliters of liquor per day, with resorption processes in the radices spinales and the granulationes arachnoideales keeping the circulating volume of cerebrospinal fluid at around 150 milliliters. The cerebrospinal fluid flows out of the ventricular system into the outer liquor space.

This task of the system is also vital and can lead to pathological changes in the brain in the event of malfunctions. The liquor is also clinically relevant with regard to liquor diagnostics, in which the cerebrospinal fluid is removed from the outer liquor space in order to examine diseases of the central nervous system .

Diseases

One of the most common diseases related to the cerebral ventricular system is the colloid cyst, which corresponds to a benign cyst structure in the third cerebral ventricle. If the cystic formations displace the foramen of Monro, cerebrospinal fluid stasis occurs. Such a liquor congestion increases the intracranial pressure and can sometimes be fatal. To prevent this, colloid cysts are removed using minimally invasive neuroendoscopic procedures.In addition to these cyst formations, a pathological expansion of the cerebrospinal fluid spaces can also occur in connection with the ventricles, which is usually preceded by an overproduction of cerebrospinal fluid. Such overproduction may be associated with masses such as tumors or blood clots . Under certain circumstances, however, an inflammatory process in the central nervous system or the destruction of brain tissue is responsible for the phenomenon. This disease also often has increased intracranial pressure. The course of treatment depends on what caused the CSF overproduction.

Typical & common brain diseases

Lisa Newlon
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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.