the csf returns to the bloodstream by way of
Cerebrospinal fluid CSF returns to the vascular system by entering the dural venous sinuses via arachnoid granulations.[2] These are outpouchings of the arachnoid mater into the venous sinuses around the brain, with valves to ensure one-way drainage.[2] This occurs because of a pressure difference between the arachnoid mater and venous sinuses.[3] CSF has also been seen to drain into lymphatic vessels,[17] particularly those surrounding the nose via drainage along the olfactory nerve through the cribriform plate. The pathway and extent are currently not known,[1] 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.[2] CSF has also been seen to be reabsorbed through the sheathes of cranial and spinal nerve sheathes, and through the ependyma.[3]