Editing Arachnoid granulation (section)

{{short description|Protrusions of the arachnoid mater for returning cerebrospinal fluid to circulation}}
{{Infobox anatomy
| Name        = Arachnoid granulation
| Latin       = granulationes arachnoideae
| Image       = Gray769-en.svg
| Caption     = Diagrammatic representation of a section across the top of the skull, showing the membranes of the brain, etc. ("Arachnoid granulation" label is at top right.)
| Image2      = Arachnoid granulations.jpg
| Caption2    = Arachnoid granulations seen on [[autopsy]], where the dura mater has been removed but the arachnoid mater is left in place.
| System      =
}}
'''Arachnoid granulations''' (also '''arachnoid villi''', and '''Pacchionian granulations''' or '''bodies''') are small outpouchings of the [[arachnoid mater]] and [[subarachnoid space]] into the [[dural venous sinuses]] of the brain. The granulations are thought to mediate the draining of [[cerebrospinal fluid|cerebrospinal fluid (CSF)]] from the [[subarachnoid space]] into the [[venous system]].<ref>{{cite book |last1=Hall |first2=John E. |last2=Hall |first1=Michael E. |title=Guyton and Hall textbook of medical physiology |year=2021 |publisher=Elsevier |location=Philadelphia, PA |isbn=978-0-323-59712-8 |edition=14th |pages=781–782}}</ref>

The largest and most numerous granulations lie along the [[superior sagittal sinus]]; they are however present along other dural sinuses as well.