A, Sylvian and insular veins. Lateral view of the sylvian fissure. The posterior two-thirds of the superficial sylvian vein is larger than the anterior third, which is very small. The large posterior segment of this superficial sylvian vein joins the vein of Labbé and the anterior end joins an anastomotic vein crossing the frontal lobe. Duplicate anastomotic veins fitting the criteria for a vein of Trolard connect the sagittal sinus to the sylvian veins: one crosses the frontal lobe and the other crosses the parietal lobe. The lip of the sylvian fissure has been retracted to expose a small deep sylvian vein, which crosses the insula and passes medially below the anterior perforated substance to join the basal vein. The lower retractor is on the planum polare, an area free of gyri on the upper surface of the temporal lobe. Further posteriorly on the upper surface of the temporal lobe are the transverse temporal gyri that form the planum temporale. B, Enlarged view of another specimen. The lower opercular lip has been retracted to expose the deep sylvian veins passing around the lumen insula to course below the anterior perforated substance and join the anterior end of the basal vein. C, The frontoparietal operculum has been removed. The veins draining the opercular lips and insula pass predominantly to the large superficial sylvian vein rather than forming a large deep sylvian vein. D, Another specimen showing the veins on the insula converging to form a deep sylvian vein that passes above the middle cerebral artery and below the anterior perforated substance to join the anterior end of the basal vein. The most anterior of the transverse temporal gyri is Heschl’s gyrus. (Images courtesy of AL Rhoton, Jr.)