Subarachnoid spaces

Spatium subarachnoideum

One, compared to subdural space, extensive space between the arachnoidean (the cobweb-like meninge) and the pian (the faithful meninge). The room is permeated by thin connective tissue strands that connect the arachnoidea with the pian. The subarachnoid space contains cerebrospinal fluid and surrounds the entire central nervous system.