Lateral Ventricle of the Brain

Overview:

All of the body’s processes occur in a systematic and sequential order, ensuring that every function of the body is executed as perfectly as possible. This necessitates precise processing and appropriate handling of the sensory input received by the organs and tissues, implying a highly functioning brain. Because the human brain is so vital and delicate, it is encased in a bony protective shell to protect it from harm. The brain is also shielded by three meningeal layers: the dura mater, the arachnoid mater, and the pia mater. Despite all of those layers, there is still a region around the brain that is vulnerable to harm.

As a result, this area is filled with clear fluid, suspending the brain within the cranium. The fluid is known as Cerebrospinal fluid (CSF) is produced by the brain’s ventricle system. Cerebrospinal fluid (CSF) is contained in four voids in the brain: two lateral ventricles, a third ventricle, and a fourth ventricle.

The lateral ventricles of the brain are detailed in this article. Their location, anatomical formation, role within the brain area and function in brain protection are all explained. This article also briefly discusses the complications associated with the lateral ventricles of the brain.

Summary of the lateral ventricle of the brain:

• Each lateral ventricle is a C-shaped chamber located deep within the cerebral cortex
• The ventricular walls are made up of the corpus callosum, caudate nucleus, thalamus, fornix, septum pellucidum, hippocampus, amygdala, and deep cerebral white matter
• A posterior, inferior and anterior horn form the structural components of the lateral ventricles
• The lateral ventricle’s posterior (occipital) horn continues posteromedially into the area of the occipital lobe and, like the rest of the lateral ventricle, has a top, lateral wall, and medial wall.
• The far more anterior portion of the corpus callosum trunk forms the roof, whereas the top of the caudate nucleus forms the floor
• The top side of the corpus callosum’s rostrum forms a little portion of the floor towards the midline. The septum pellucidum forms the medial wall.
• The lateral ventricles have a roof, a bottom layer and median walls
• Like the rest of the ventricles of the brain, the lateral ventricles help provide a fluid-filled cavity for the brain and submerge it for its protection, manufacture cerebrospinal fluid and help circulate it
• Ventriculomegaly, hydrocephalus and tumours are some of the clinical complications that concern the lateral ventricles of the brain
• Ventriculomegaly is a disorder that causes the lateral ventricle to develop improperly. It is linked to mental illnesses such as Alzheimer’s disease, dementia, hydrocephalus, bipolar disorder and many more

Location:

Each lateral ventricle is a chamber in the shape of a C and is present deep within the cerebral cortex. As the lateral ventricle loops around the thalamus, or central core of the brain, other components within the ventricle, such as the choroidal fissure, fornix, caudate nucleus, and choroid plexus, take on a C shape. Each lateral ventricle is made up of five sections: the frontal horn, the body, the atrium, the occipital horn, and the temporal horn.

The corpus callosum, caudate nucleus, thalamus, fornix, septum pellucidum, hippocampus, amygdala, and deep cerebral white matter constitute the ventricular walls.

Structure:

On either part of the cerebral hemispheres, there are two lateral ventricles. They connect with the third ventricle on the inferior side via the interventricular foramen. The anterior horn, or initial part, is the section of the lateral ventricle anterior to the foramen. This is followed by the central section. The central part’s front, middle, and back are designated second, third, and fourth, correspondingly. The fourth segment of the ventricle splits into the fifth, also known as the posterior horn, and the sixth, known as the inferior horn. The frontal, temporal, and occipital lobes include the anterior, inferior, and posterior horns, respectively.

The lateral ventricle’s central portion is anteroposteriorly extended. It connects with the anterior horn at the anterior side at the position of the interventricular foramen. The body eventually approaches the splenium of the corpus callosum.

It has a triangular cross-section with a roof, floor, and medial wall, with the top surface layer and bottom surface meeting on the lateral aspects.

The trunk of the corpus callosum forms the top surface layer.

The septum pellucidum and the body of the fornix, which is shared by two lateral ventricles, create the medial wall.

The bottom layer is primarily created medially by the superior layer of the thalamus and on the lateral side by a structure known as the caudate nucleus. The stria terminalis and thalamostriate veins are located between these two structural components.

Posterior or occipital horn of the lateral ventricles:

The lateral ventricle’s posterior (occipital) horn continues posteromedially into the area of the occipital lobe and, like the rest of the lateral ventricle, has a top, lateral wall, and medial wall.

The tapetum forms the ceiling and lateral walls, whereas the medial wall has two peaks, one inferior and one superior, and is known as the calcar avis.

A feature known as the bulb of the posterior horn is located above those altitudes. This bulb is created by fibres of the forceps major running towards the back direction from the corpus callosum’s splenium.

Anterior or frontal horn of the lateral ventricles:

The anterior (also known as the frontal) horn of the lateral ventricle is isolated from the centre half by an imagined vertical path that passes at the position of the interventricular foramen. This addition features a triangle cross-section and a roof, medial wall and a base layer or floor. The corpus callosum’s genu and rostrum help to shut it off on the anterior end.

The far more anterior portion of the corpus callosum trunk forms the roof, whereas the top of the caudate nucleus forms the floor. The top side of the corpus callosum’s rostrum forms a little portion of the floor towards the midline. The septum pellucidum forms the medial wall.

Inferior or temporal horn of the lateral ventricles:

The hippocampus, along with the alveus and fimbriae, composes the majority of the base of the inferior horn. The collateral eminence is uplift in the lateral region of the surface caused by the inner folding of the white mater that lays deep to the collateral sulcus.

The lateral section of the roof (lateral wall) is made up of tapetum fibres, whereas the medial portion is made up of the caudate nucleus tail and the stria terminalis. From the base of the central portion, these components continue through the top layer of the inferior horn. The caudate nucleus tail and the stria terminalis cease on the anterior side of the amygdaloid complex, which is present in the most anterior portion of the top surface layer of the lateral ventricles.

The lateral ventricle’s significant aspect is the inferior (temporal) horn. It goes anteroinferiorly into the temporal lobe from the posterior end of the central area. It has an anterior edge that is adjacent to the cerebrum’s uncus, a base, and a top surface layer/roof. The inferior horn’s roof is mostly produced by the tapetum of the corpus callosum and the cauda of the caudate nucleus.

The inferior horn features a small hollow in cross-section that is bordered on the top and laterally by the top, and beneath it and medially by the base.

This arrangement is the reason why the lateral section of the ceiling is known as the lateral wall, while the medial part of the floor is known as the medial wall.

Function:

Cerebrospinal fluid is produced by the ventricle covering (CSF). The cerebrospinal fluid (CSF) is then absorbed in the subarachnoid region after passing through the ventricular system.

Cerebrospinal fluid (CSF) is thought to have several key roles in the brain. It helps to make the brain buoyant, reducing the stress and agony that gravity and movements could otherwise produce.

The reality is that if the brain is not maintained in some form of a liquid phase, it will become altered and twisted beneath its bodily mass, and sensitive tissue cells will begin to rip and be harmed. The barrier of Cerebrospinal fluid (CSF) that covers the brain also acts as a barrier against potential hazards connected with mechanical stress or any other type of applied force, such as if a person falls. Another example would be, if a person falls and harms their head severely, or if they are beaten and a blunt force is applied to the head.

Moreover, as Cerebrospinal fluid (CSF) passes across the brain, it transfers poisonous compounds as well as other waste materials and substances into the bloodstream, where they are then discharged by processes such as the kidney’s filtration system. Regardless of pressure fluctuations within the ventricles, the rate of Cerebrospinal fluid (CSF) production in the ventricles stays constant.

If the flow of Cerebrospinal fluid (CSF) is impeded at any point or site in the ventricular system, it might be a problem. Cerebrospinal Fluid (CSF) will continue to be available and produced, but it will be unable to leave the platform.

As a result, the stress inside the ventricles would rise, and the increasing pressure may effectively cause the ventricles to enlarge. The expanding ventricles may then clash with other brain regions, leading to a variety of health complications (based on where the blockage occurred and which structures or tissues are most influenced by this expansion). When this occurs in children whose skulls have not fully ossified (typically under the age of 2), the head may enlarge.

When CSF is produced in the lateral ventricle, it fills the cavity before passing through the interventricular foramen of Monro and entering the third ventricle. Cerebrospinal fluid (CSF) produced in the third ventricle departs the area via the Sylvius cerebral aqueduct and enters the fourth ventricle in addition to CSF produced in the lateral ventricle.

The lateral ventricles are the biggest of the brain’s four interconnected chambers that are filled with fluid.  The cerebral ventricular system is made up of these chambers and their interconnected passages.

The third and fourth ventricles are the system’s other two cavities, while the cerebral aqueduct of Sylvius is one of the interconnecting systems that guarantee interaction between the third and fourth ventricles. The ventricles’ job is to hold the cerebrospinal fluid (CSF) and provide a pathway for its movement.

Complications involving the lateral ventricles of the brain:

A CT scan can be used to determine the volume of the lateral ventricles and other structures within the brain. Physicians can use the scan to determine not just the length of the ventricles, but also the density of the cerebrospinal fluid (CSF) they hold. This data can be utilized to prevent and manage brain disorders such as hydrocephalus, which is an excessive accumulation of fluid in the ventricle.

Ventriculomegaly:

Ventriculomegaly is a disorder that causes the lateral ventricle to develop improperly. It is linked to mental illnesses such as Alzheimer’s disease, dementia, hydrocephalus, bipolar disorder, schizophrenia as well as brain disorders related to movements such as Huntington’s disease and Parkinson’s disease.

The explanation of ventriculomegaly is uncertain, but it is extremely debated that atrophy of structural components present around the lateral ventricles, as well as a decrease in the amount of the nearby periventricular structures, may be major factors responsible, allowing the ventricles to broaden and fill in the region.

One possibility is a stoppage of venous blood or Cerebrospinal fluid (CSF) circulation which leads to an increase in the volume of cerebrospinal fluid (CSF) in the ventricles. A further explanation is that mechanical pressure and shear pressures cause injury and atrophy of surrounding structures that encircle the ventricles.

A few of the hypothesized reasons for deformation and shear stresses include venous blood and Cerebrospinal fluid (CSF) flow obstruction, venous back pressure, anomalous pressure waves, and pounding-type waves known as water hammers.

Tumours of the lateral ventricles:

Tumours of the lateral and third ventricles constitute a special problem to neurosurgeons due to their deep placement and proximity to critical neuronal and circulatory systems. Supratentorial and infratentorial intraventricular tumours are frequent in kids, accounting for roughly 41% of lateral and third ventricular tumours. However, only 7 per cent of occurrences are in the older population.

In adults, nearly half of all intraventricular mass lesions are situated in the lateral ventricle, however, in kids, the ratio is significantly smaller. Intraventricular mass lesions are caused by a wide range of benign and malignant malignancies. In the elder age group, the most common lateral ventricle tumours comprise astrocytoma, meningioma, glioblastoma, ependymoma, and choroid plexus papilloma.

In comparison, the most common lateral ventricle cancers in children include subependymal giant cell astrocytoma, ependymal, choroid plexus papilloma, choroid plexus carcinoma and astrocytoma. 

Although numerous surgical methods can be used to access intraventricular lesions, surgical excision remains the primary treatment method for lateral and third ventricular malignancies.

The surgical technique is determined mostly by the position, length, and nature of the lesion; the surface area of the ventricles; the tumour’s proximity to the third ventricle; vascularity; venous outflow; and the lesion’s connection to nearby tissues.

While transcortical or transcallosal methods can yield in full tumour excision, they are linked with an elevated risk of brain parenchymal damage.

Hydrocephalus:

Hydrocephalus is a condition characterised by excessive cerebrospinal fluid (CSF) production and ventricular size expansion or enlargement, also known as ‘water on the brain’. A hydrocephalus-causing blockage can be caused by several reasons, including a tumour, infection, or congenital abnormalities.

Hydrocephalus is commonly treated by surgically placing a shunt that drains excess Cerebrospinal fluid (CSF) from the ventricles into the abdominal cavity. This treatment has the potential to be effective; but, if the reason for the obstruction is not addressed, more surgical procedures may be required to resolve this issue. 

These include procedures such as the replacement of an overgrown shunt or the treatment of an infected shunt.

Conclusion:

Each lateral ventricle is a C-shaped chamber located deep within the cerebral cortex. Other ventricle components, such as the choroidal fissure, fornix, caudate nucleus, and choroid plexus, take on a C shape when the lateral ventricle loops around the thalamus, or central core of the brain. The structural components of the lateral ventricles are a posterior, inferior, and anterior horn. There is a roof, a bottom layer, and median walls in the lateral ventricles. The lateral ventricles, like the rest of the brain’s ventricles, help provide a fluid-filled compartment for the brain and immerse it for safety, as well as produce and circulate cerebrospinal fluid. Ventriculomegaly, hydrocephalus and tumours are some of the clinical complications that concern the lateral ventricles of the brain. 

Reference list

• Chaichana, K. and Quiñones-Hinojosa, A. (2019) Comprehensive overview of modern surgical approaches to intrinsic brain tumors. London, United Kingdom: Academic Press. Available at: https://books.google.com.pk/books?id=erKKDwAAQBAJ.
• Crossman, A.R. and Neary, D. (2010) Neuroanatomy: An illustrated colour text. illustrated by Ben Crossman. 4th edn. (Illustrated Colour Text). Edinburgh: Churchill Livingstone/Elsevier. Available at: https://doctorlib.info/anatomy/neuroanatomy-illustrated-colour-text/6.html (Accessed: 20 July 2021).
• Elwatidy, S.M. et al. (2017) ‘Tumors of the lateral and third ventricle: surgical management and outcome analysis in 42 cases’, Neurosciences (Riyadh, Saudi Arabia), 22(4), pp. 274–281. doi: 10.17712/nsj.2017.4.20170149
• Okpe, O. (2021) Lateral Ventricles: Anatomy and Function. Available at: https://www.kenhub.com/en/library/anatomy/lateral-ventricles (Accessed: 20 July 2021).
• ThoughtCo (2021) Ventricles of the Brain, 20 July. Available at: https://www.thoughtco.com/ventricular-system-of-the-brain-3901496 (Accessed: 20 July 2021).