# The Meninges --- The **cranial meninges** are the layers of protective tissue that surround and protect the [[brain]]. There are a similar set that cover the [[spinal cord]], with some variations. ![[meninges.png]] ## Pia Mater The **pia mater** is the innermost meninge. It is a thin layer of [[loose connective tissue|areolar tissue]] that attaches directly to the brain, and follows every little bump and ridge. ## Arachnoid Mater The **arachnoid mater** is named for it's spiderweb-like formation. It fills in the space between the other two meninges, and can act as a cushion, compressing and expanding in response to stresses. The **arachnoid traberculae** are the string-like formations that allow for the compression and expansion. A lot of interesting things can happen with this layer, as it is associated with the **subarachnoid space**. This is where [[blood vessels]] move around the outside of the brain. ## Dura Mater The **dura mater** is the outermost meninge, attached to the arachnoid layer and the inner layer of the skull's [[bone|periosteum]]. ## Problems with the Meninges - [[hemorrhagic stroke]] can be caused by a bleed in the subarachnoid space - [[meningitis]] is an inflammation of the meninges, and is a very serious condition typically caused by a bacterial or viral infection. ___