Meningar
The meninges are the protective membranes surrounding the brain and spinal cord. They consist of three layers: the dura mater (outer), the arachnoid mater (middle), and the pia mater (inner). Together they enclose the subarachnoid space, which contains cerebrospinal fluid (CSF) and major blood vessels.
The dura mater is a tough, fibrous outer membrane. In the skull there are two dural layers,
The arachnoid mater is a thin, avascular membrane beneath the dura. It forms a web-like network, and
The pia mater is the delicate innermost layer that closely follows the contours of the brain and
Clinically relevant spaces include the subdural space, a potential space between dura and arachnoid, and the
A related term is meningioma, a usually slow-growing tumor that arises from the meningeal layers, most often