Structures and Functions of the Cranial Meninges

00:01 Welcome to this presentation on the cranial meninges. Our first slide is going to demonstrate structural considerations of the cranial meninges. The first consideration or the take home message here is there are three meningeal layers. The first is the dura mater and that is highlighted in green. This will be the external or outermost meningeal layer. The middle of the three layers is referred to as the arachnoid or arachnoid mater. That is shown here also now in green. It is a thinner structure. Our third and final meningeal layer is referred to as the pia mater. The pia mater is shown here as a very thin, green line on the surface of the brain. At this point, it will serve us well to define the leptomeninges. The leptomeninges comprise the innermost two layers of the meninges. So we would have the arachnoid layer again shown in green, as well as the pia mater. With meningitis, these are the layers that would be involved in this inflammatory state. The last structural consideration is that the cranial meninges are continuous with the spinal meninges. Now, let’s take a look at functional considerations. The first is the cranial meninges provide for protection of the brain.

02:09 They also allow support for vascular structures that traverse this region of our anatomy.

02:18 Lastly, cerebrospinal fluid is found in a space called the subarachnoid space. Cerebrospinal fluid helps to confer normal brain function. The subarachnoid space is identified right in through here. We’ll discuss this space in additional detail shortly.