Meningitis is the inflammation of the pia and arachnoid mater.

The arachnoid mater is the middle protective layer.

The arachnoid mater continues down the spinal cord too, and the subarachnoid layer with it.

The arachnoid mater is a thin, transparent membrane.

The cerebrospinal fluid that surrounds the spinal cord is contained by the arachnoid mater.

In subdural hematoma, bleeding occurs between the dura and the arachnoid mater.

The arachnoid mater is one of the three meninges, the protective membranes that cover the brain and spinal cord.

The other two meningeal layers are the pia mater and the arachnoid mater.

The middle element of the meninges is the arachnoid mater, so named because of its spider web-like appearance.

In contact with the inner surface of the dura is another membrane called the arachnoid mater ("arachnoid").

The term leptomeningeal refers to the two deep layers of the meninges - the pia mater and the arachnoid mater.

It may also be the site of trauma, such as a subdural hematoma, causing abnormal separation of dura and arachnoid mater.

There are two subdivisions of arachnoid mater within the velum interpositum, the dorsal layer and the ventral layer.

Subdural hemorrhage results from tearing of the bridging veins in the subdural space between the dura and arachnoid mater.

Most meningiomas grow from the arachnoid mater inward applying pressure on the pia mater and therefore the brain or spinal cord.

Subarachnoid hematoma - between the arachnoid mater and pia mater (the subarachnoid space)

The dura mater is a sac (aka thecal sac) that envelops the arachnoid mater.

The arachnoid mater (so named because of its spider-web-like appearance) is a loosely fitting sac on top of the pia mater.

In the cadaver, due to the absence of cerebrospinal fluid in the subarachnoid space, the arachnoid mater falls away from the dura mater.

In mammals, the meninges consist of three layers: the dura mater, the arachnoid mater, and the pia mater.

Other patients have seen the onset of bobble-head doll syndrome from the presence of a suprasellar cyst in the arachnoid mater of the meninges.

They drain via the arachnoid villi, which are outgrowths of the arachnoid mater (the middle meningeal layer) that extend into the venous sinuses.

The arachnoid mater covering the brain is referred to as the "arachnoidea encephali", and the portion covering the spinal cord as the "arachnoidea spinalis".

Blood gathers within the outermost meningeal layer, between the dura mater, which adheres to the skull, and the arachnoid mater, which envelops the brain.

It is separated from the subarachnoid space by the diaphragma sella, therefore the arachnoid mater and thus cerebral spinal fluid cannot enter the sella turcica.