The term anterior calcarine fissure (clfa) refers to a rostral extension of the calcarine fissure, identified by dissection, caudally on the medial surface of the cerebral hemisphere in the human ( Roberts-1970 ). In some cases the extension reaches the hippocampal fissure ( Duvernoy-1992 ) and forms the boundary between the isthmus of the cingulate gyrus (CGG) and the posterior parahippocampal gyrus (PHGp) of the limbic lobe (LLB). While the calcarine fissure of the macaque ordinarily extends equally far into the limbic lobe, the rostral portion is not named ( Martin-2000; Paxinos-2009a ). Comparable structures are not found in the smooth cerebral cortex of the rat or mouse ( NeuroNames ). Updated 21 Aug 2024..