The daily production of CSF is

(A) 550 ml# Cerebrospinal fluid (CSF)> Total volume of CSF is 150 mis.> Daily production is 550 mls/day so the CSF turns over about 3 to 4 times per day.> CSF is formed by the choroid plexus (50%) and directly from the walls of the ventricles (50%).> CSF flows through the foramens of Magendie & Luschka into the subarachnoid space of the brain and spinal cord.> It is absorbed by the arachnoid villi (90%) and directly into cerebral venules (10%).> Normal intracerebral pressure (ICP) is 5 to 15 mmHg.> Rate of formation of CSF is constant and is not affected by ICR> Absorption of CSF increases linearly as pressure rises above about 7 cms H20 pressure.> At a pressure of about 11 cms H20, the rate of secretion & absorption are equal.