Sanai et al. from the Brain Tumor Research Center, Department of Neurological Surgery, UCSF Medical Center USA, also proposed a different subdivision of the insular surface into quadrants, with the horizontal line set along the sylvian fissure and the vertical line perpendicular to it along the foramen of Monro, with a more straightforward application for insular gliomas, which were mostly located underneath the anterior half of the insula in their series 1).