Normal CSF volume in adults is

(B) 150 ml # CEREBROSPINAL FLUID:> Lumbar CSF pressure is normally 70-180 mm CSF.> Up to pressures well above this range, the rate of CSF formation is independent of intraventricular pressure.> However, absorption, which takes place largely by bulk flow, is proportionate to the pressure.> At a pressure of 112 mm CSF, which is the average normal CSF pressure, filtration and absorption are equal.> Below a pressure of approximately 68 mm CSF, absorption stops.