Cerebrospinal Fluid

Cerebrospinal fluid is a clear colorless fluid consisting of glucose, urea, proteins and salts in addition to some white blood cells. Cerebrospinal fluid circulates continuously around the brain where it acts as a cushion against jarring or sudden shocks. It also circulates nutritive substances filtered from the blood. The formation of cerebrospinal fluid is continuous and the direction in which it circulates is from top to bottom i.e., from the lateral ventricles down through the third and fourth ventricles and into basal cisterns. The basal cisterns area dilated portion of the subarachnoid space at the base of the brain. The cerebrospinal fluid is eventually absorbed back into the general venous circulation by way of the arachnoid villi that project into the various venous sinuses of the brain. This formation and absorption rate results in a fairly constant volume of circulating fluid. If there is increased production, decreased absorption or blockage of flow, an increased accumulation of fluid within the ventricles will result, resulting in raised intracranial pressure