The cerebrospinal fluid is secreted by the choroids plexuses in the lateral third and fourth ventricles. It leaves the ventricular system through the foramina of magendie and luschka and flows through the cerebral and spinal subarachnoid spaces. It is returned into the venous sinuses by the arachnoids villi. In health the fluid is clear and colorless. The pressure at the lumber theca with the action lying on his side is 50 to 150mm if cerebral. Spinal fluid. It contains less than 5 lymphocytes prêt cm. and it’s important chemical constituents are protein 20 45 mg glucose 50 80 mg chloride as sodium chloride 700-750 mg all per 100ml.