The granulations are thought to mediate the draining of cerebrospinal fluid (CSF) from the subarachnoid space into the venous system.

[2] The arachnoid granulations may be lodged within granular foveae — small pits upon the inner surface of the cranial bones.

[2] The granulations develop during childhood as separate arachnoid villi gradually aggregate into macroscopic clumps.

[8] A suggested alternative or additional function of the granulation may be the dispersal of the overpressure wave formed within the subarachnoid space by the pulsation of arteries during systole.

As the venous sinuses are enclosed in rigid dural structures, they represent a non-distensible compartment into which subarachnoid pressure increases may be dispersed.