Fig. 1

CSF circulation. Overview of the ventricular system. CSF is produced and flows from the choroid plexuses in the lateral ventricles into the third and then fourth ventricle via the foramina of Monro and the cerebral aqueduct, respectively. From the IVth ventricle, CSF empties into the cisterns of the skull base through the foramen of Magendie and foramina of Luschka and subsequently into the lumbar CSF space and the subarachnoid space at the sagittal sinus. Cardiac contraction induces an arterial distension during systole and a subsequent recoiling during diastole. A portion of this energy is transferred to the brain in the form of brain pulsation and to the CSF in the form of CSF pulsation. This dissipation of arterial blood flow energy by the CSF pulsation energy provides for the maintenance of low intracranial pressure (ICP) according to the Windkessel effect on CSF flow