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