Fig. 15 Blood supply of striate cortex. Medial surface of left occipital lobe with visual cortex outlined by broken line. Calcarine and parieto-occipital fissures are opened to show course of cortical branches of posterior cerebral artery. Note potential triple supply to macular area, via the calcarine, posterior temporal, and middle cerebral arteries. (Smith CG, Richardson WFG: The course and distribution of the arteries supplying the visual (striate) cortex. Am J Ophthalmol 61:1391, 1966)