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

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

[8] The granulations are sparse during early life, possibly underscoring the importance of alternate mechanisms of drainage.

[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.