=====Anterior perforated substance=====
Irregularly quadrilateral area in front of the [[optic tract]] and behind the olfactory trigone, from which it is separated by the fissure prima; medially and in front, it is continuous with the subcallosal gyrus; it is bounded laterally by the lateral stria of the olfactory tract and is continued into the [[uncus]].

Its gray substance is confluent above with that of the corpus striatum, and is perforated anteriorly by numerous small blood vessels that supply such areas as the [[internal capsule]].