Right cerebral hemisphere (upper and lower left, and left half of basal view). All cortical branches of the ACA arise directly from pericallosal artery and are shown in blue, green, and red. The callosomarginal artery is absent in 18% of hemispheres. Left hemisphere (upper and lower right, and right half of basal view) shows four of the major cortical branches arising from the callosomarginal artery (yellow area). The anterior internal frontal through the paracentral arteries arise from the callosomarginal artery. The maximum number of cortical branches that arise from the callosomarginal artery is five. The terminal branch of the pericallosal artery passes around the splenium of the corpus callosum toward the foramen of Monro. The inferior parietal artery is absent. (Images courtesy of AL Rhoton, Jr.)