====== Subarachnoid space ======

Anatomic space between the [[arachnoid]] membrane and [[pia mater]],the two innermost layers covering the brain.

The subarachnoid space contains [[cerebrospinal fluid]] (CSF) and [[blood vessel]]s.

It is occupied by spongy tissue consisting of trabeculae (delicate connective tissue filaments that extend from the arachnoid mater and blend into the pia mater) and intercommunicating channels in which the [[cerebrospinal fluid]] is contained.
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see [[Subarachnoid cistern]]
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[[Tarlov cyst]] is an abnormal expansion of the [[spinal nerve]] sleeve, and communicates with the [[subarachnoid space]] via a perineural fistula.

===== Subarachnoid hemorrhage =====

see [[Subarachnoid hemorrhage]].