One may describe 4 types of individual dispositions for the postero-median choroideal and thalamic system: Type A with a single artery of anterior origin, type P with two consecutive arteries (a mesencephalothalamic artery and a posteromedian artery of posterior origin), type D with two parallel arteries and type O. One may also describe 4 types of individual dispositions for the postero-lateral choroideal and thalamic system. Type C is constituted by a single postero-lateral chorideal artery giving off thalamic branches. Type D comprises two arteries, a postero-lateral choroideal and a postero-lateral thalamic artery. According to the relative importance of the two arteries one may describe subtypes Dc, De and Dt. Type T is constituted by a single postero-lateral thalamic artery giving off choroideal branches. In type H hippocampothalamic arteries intervene. We also studied the variations of the ending point of the anterior choiroideal artery.