The nodular white excresences seen here over the cerebral hemispheres at the vertex on both sides of the central fissure with falx cerebri of the brain are the arachnoid granulations. This is where the cerebrospinal fluid produced in the choroid plexuses of the ventricles and which has circulated out of the foramina of Magendie and Luschka and into the subarachnoid space is reabsorbed.