This results in sudden bleeding into the space between the middle lining of the brain (arachnoid membrane) and the brain itself.

Arachnoid cyst (between the surface of the brain and the cranial base or on the arachnoid membrane)

A subarachnoid hemorrhage is bleeding into the subarachnoid space-the area between the arachnoid membrane and the pia mater surrounding the brain.

Researchers believe that most cases of arachnoid cysts are developmental malformations that arise from the unexplained splitting or tearing of the arachnoid membrane.

The outermost membrane, the dura mater, is a thick durable membrane, which is attached to both the arachnoid membrane and the skull.

Using a microscope and micro-instruments, the arachnoid membrane is dissected allowing visualization of the 8th, 7th and finally the trigeminal nerve.

Subarachnoid hemorrhage involves bleeding into the space between the arachnoid membrane and the pia mater.

In the central nervous system, the subarachnoid cavity (subarachnoid space) is the interval between the arachnoid membrane and pia mater.

The condition may be caused by foreign agents such as anesthesia drugs or testing dyes injected into the spine or arachnoid membrane.

Intrathecal is an adjective that refers to something introduced into or occurring in the space under the arachnoid membrane of the brain or spinal cord.