The Insular Region. K, Schematic drawing depicting a posterosuperior view of the walls of the insula. The anterior wall is in yellow, the superolateral facet is in light blue, and the inferolateral facet is in red. L, Basal view of the right frontal lobe. 1, anterior orbital gyrus; 2, lateral orbital gyrus; 3, medial orbital gyrus; 4, posterior orbital gyrus; 5, rectus gyrus; 6, pars orbitalis; 7, transverse gyrus; 8, insular pole. The arrows indicate anterior insular cleft. The arrowheads indicate posteromedial limb of the orbital sulcus. Asterisk, posteromedial orbital lobule, just anterior to the lateral olfactory stria and lateral to the olfactory sulcus. (Images courtesy of AL Rhoton, Jr.)