Dura Mater - Outermost layer
Tough, inflexible and 'leather like'.
Lines the inside of the skull where it's attached to the bones.
Arachnoid mater - Middle layer (separated from the pia mater by the subarachnoid space)
Delicate spider-web like structure
Attached to the inside of the dura
Surrounds the inside of the brain and spinal cord
(aracnoidea encephali & spinalis)
Pia mater - Delicate innermost layer
Thin / mesh like
Closely envelops entire surface of brain
Runs down fissures of the cortex
Supplies brain tissue with blood vessels
Subarachnoid space - Between arachnoid mater and pia mater is the CSF which absorbs and disperses excessive mechanical forces that might otherwise cause serious injury. It's produced by the choroid plexuses in the lateral ventricles and drains into the dural venous sinus into the internal jugular vein.