Medial temporal lobe and hippocampal formation. Inferiorly, the inferior temporal gyrus runs adjacent to the occipitotemporal gyrus. The parahippocampal gyrus is separated from the occipitotemporal gyrus by the collateral sulcus, which has an intraventricular prominence called the collateral eminence which runs adjacent and parallel to the hippocampus. The dentate gyrus is adjacent and medial to the fimbria of the fornix. Posteriorly within the temporal horn, the calcar avis is a prominence representing the calcarine fissure. Medial to the hippocampal formation is the ambient cistern, tentorial edge and mesencephalus. (Image courtesy of AL Rhoton, Jr.)