The Medial Temporal Region. E, Superior view of the left MTR showing the relation of the ventricular and the cisternal components of the MTR to the tentorial edge and cerebral peduncle. The part of the uncus behind the apex faces the cerebral peduncle across the crural cistern. The apex of the uncus is positioned lateral to the oculomotor nerve. The tentorial edge crosses below the medial part of the uncus. F, Lateral view of the ventricular surface of the medial temporal lobe. The anterior segment of the uncus contains the amygdala and faces the carotid, anterior choroidal, and MCA arteries. The posterior segment of the uncus, which forms the posterior part of the anterior segment of the medial temporal lobe, contains the head of the hippocampus and is located anterior to the inferior choroidal point. The lateral geniculate body is located just above the choroidal fissure and the middle segment of the medial temporal lobe. The choroidal fissure, along which the choroid plexus (removed) attaches, is located between the fimbria and the thalamus. G, The lateral part of the thalamus has been removed to expose the body and head of the hippocampus and the body, crus, and fimbria of the fornix forming the outer margin of the choroidal fissure. The uncal recess extends medially between the ventricular surface of the amygdala and the head of the hippocampus. The amygdala and head of the hippocampus are located in the anterior segment of the medial temporal lobe and the body of the hippocampus is positioned in the middle segment of the medial temporal lobe. H, Lateral view of another temporal horn following a fiber dissection to show the relation of Meyer’s loop of the optic radiation to the roof of the anterior segment of the MTR. The uncal recess extends medially between the amygdala and hippocampal head. (Images courtesy of AL Rhoton, Jr.)