Welcome to this presentation on the ventricular system. The ventricular system is a series of fluid-filled
cavities that are found in the brain. These cavities do communicate with one another. This ventricular
system is in communication with the spinal cord as well. So let’s take a look at our first slide.
What I want you to understand from this slide is that the fluid-filled cavities in the brain and the fluid is
cerebrospinal fluid are termed ventricles. So what are the ventricles then that contain the cerebrospinal fluid?
The first to point out to you are the large, paired lateral ventricles. You can see the various components
of the lateral ventricle in this particular view. It will wrap around and curve into the temporal lobe.
This extension of the lateral ventricle projects toward the occipital lobe. The next ventricular component
is a single third ventricle which we see here. This has an anatomic relationship with the diencephalon.
Then your last component is the fourth ventricle that we see down in through here. It has a relationship
with the brainstem lying anterior to it and then a cerebellum that lies posterior to it. These fluid-filled
ventricles communicate with one another and that allows the movement or circulation of the cerebrospinal
fluid from one filled cavity to another. So the components that allow for this communication then are
firstly is that the lateral ventricles, each one will communicate with the third ventricle via this communication here.
This is referred to as an interventricular foramen. So there will be one on the left side as we see here.
There will be another interventricular foramen from the right lateral ventricle that would also then
communicate with the third ventricle. From the third ventricle to the fourth ventricle, there is yet another
opening or form of communication. This is termed the cerebral aqueduct. We see the beginning portion
of it here. Then it is out of view here located behind this portion of the lateral ventricle in the temporal lobe.
Then we see it terminating in the fourth ventricle below. There are also communications between the
fourth ventricle and other structures. There are two lateral apertures. Here is one. Then here is the other.
These communicate with the subarachnoid space of the brain. This space is in communication with the spinal cord,
so that the cerebrospinal fluid would also flow within the subarachnoid space of the spinal cord as well as the brain.
The final communication of the fourth ventricle is with the subarachnoid space as well. That is referred
to as the median aperture. The last communication that we see here is a continuation of the fourth
ventricle inferiorly. This is going to communicate with the central canal of the spinal cord itself. So three
apertures, two lateral, one median, and that allows the passage of cerebrospinal fluid from the fourth
ventricle into the subarachnoid spaces of the brain and spinal cord. Then the central canal allows the flow of
cerebrospinal fluid from the fourth ventricle into the spinal cord itself. This particular slide or table
that you’re going to see is a summary of the ventricles and how they communicate with another structure.
So with the interventricular foramen, that communicates with the lateral ventricle. Then the lateral ventricles
will communicate with the third ventricle. The cerebral aqueduct is going to allow for the communication
of cerebrospinal fluid with the third ventricle into the fourth ventricle. You have two lateral apertures.
This will allow the movement of cerebrospinal fluid from the fourth ventricle into the subarachnoid space.
The subarachnoid space between the brain and spinal cord would be continuous. Then the
median aperture of the fourth ventricle would also communicate with the subarachnoid space.