The term intermediate orbital gyrus (ORGin) refers to a convolution on the ventral surface of the frontal lobe (FLB) in the human and macaque ( NeuroNames ). Identified by dissection, it is separated from the lateral orbital gyrus (ORGl) by the lateral orbital sulcus (los) and from the medial orbital gyrus (ORGm) by the medial orbital sulcus (mos). In the human the ORGin is divided into an anterior orbital gyrus (ORGa) and a posterior orbital gyrus (ORGp) by the transverse orbital sulcus (tos). Histologically, the rostral part of the ORGin in the human is area 11l ( Ongur-2003 ); in the macaque it includes area 11l and the medial part of area 12m as well ( Carmichael-1994 ). The caudal part in the human is area 13l; in the macaque it includes area 13l and area 13m. For some decades the ORGin of the macaque has was confusingly named ‘lateral orbital gyrus’ ( Krieg-1975 Martin-2000 ). An equivalent structure is not found in the smooth cerebral cortex (CTX) of the rat or mouse ( NeuroNames ). Updated 9 Sep 2024.