CSF outflow isn't only through the arachnoid granulations

We teach our medical students that CSF outflow is through the arachnoid granulations into the venous sinuses. That's true, and good enough for a second year medical school curriculum. But we should keep in mind that some CSF appears to be absorbed by the ependymal lining of the ventricles, as well as in the spinal subarachnoid space and through the walls of the capillaries in the pia mater. Additionally, to quote my source on all of this (Clinically Oriented Anatomy, 2nd edition, by Keith Moore), "some CSF is probably absorbed into the lymphatics adjacent to the subarachnoid space around cerebrospinal nerves (e.g., the optic nerves)."