Tags: Anatomical Structure.
Arachnoid granulations (or arachnoid villi) are small protrusions of the arachnoid (the thin second layer covering the brain) through the dura mater (the thick outer layer). They protrude into the venous sinuses of the brain and allow cerebrospinal fluid (CSF) to exit the sub-arachnoid space and enter the blood stream.Largest granulations lie along the superior sagittal sinus a large venous space running from front to back along the centre of the head (on the inside of the skull).
