Microanatomy of the pericallosal arterial complex

Object. The pericallosal arterial complex supplies the callosal and perical losal regions, as well as the anterior two thirds of the medial and superom edial aspects of both hemispheres. It is composed of the pericallosal arter y (that is, the segment of the anterior cerebral artery located distal to t he anterior communicating artery [ACoA]) and the median callosal artery (or third pericallosal artery), which originates from the ACoA. This system wa s studied in 46 specimens (23 human cadaver heads) injected with colored la tex. Methods. After being injected with colored latex, embalmed, and bleached, t he specimens were studied with the aid of optic magnification. The pericallosal artery was found to be divided into four segments (A,A, in the proximodistal direction). After giving rise to central, callosal, and cortical branches, it terminated near the splenium of the corpus callosum a s the posterior pericallosal artery, or on the precuneus as the inferomedia l parietal artery. Conclusions. The authors propose a logical classification of the different variations in the pericallosal arterial complex based on embryological deve lopment. This complex can be considered a hemodynamic solution to an abnorm al regression of one of its parts, which is balanced by the development of supplemental channels from other parts.