CSF returns to the vascular system by entering the dural venous sinuses via arachnoid granulations.
This occurs because of a pressure difference between the arachnoid mater and venous sinuses.
CSF has also been seen to drain into lymphatic vessels, particularly those surrounding the nose via drainage along the olfactory nerve through the cribriform plate. The pathway and extent are currently not known, but may involve CSF flow along some cranial nerves and be more prominent in the neonate.[3] CSF turns over at a rate of three to four times a day.
CSF has also been seen to be reabsorbed through the sheathes of cranial and spinal nerve sheathes, and through the ependyma.