Fig. 15. Blood supply of the striate cortex. Medial surface of the left occipital lobe with visual cortex outlined by broken line. Calcarine and parieto-occipital fissures are opened to show the course of the cortical branches of the posterior cerebral artery. Note potential triple supply to macular area, through 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)