View of a lateral section of the brain. The roof and the lateral surface of the temporal horn were dissected. The three hippocampal segments are shown—head, body, and tail forming the floor of the temporal horn. The origin of the posterolateral choroidal artery in the P2P segment, the intraventricular trajectory, and the anastomoses with anterior choroidal artery in the choroid plexus glomus are shown in the figure. 1, P2P segment in the ambient cistern; 2, anterior choroidal artery; 3, posterolateral choroidal artery; 4, fimbria; 5, subiculum; 6, choroid plexus glomus; 7, bulb of the corpus callosum; 8, calcar avis; 9, collateral trigone; 10, body of the caudate nucleus; 11, putamen; 12, globus pallidus; 13, internal capsule; 14, thalamus. (Image courtesy of E de Oliveira)