The term orbital sulcus refers to an H shaped combination of sulci on the ventral surface of the frontal lobe (FLB) in the human. Identified by dissection, it is composed of the lateral orbital sulcus (los), the medial orbital sulcus (mos) and the transverse orbital sulcus (tos) (Wikipedia). It is not found in the macaque ( Martin-2000 ) nor the smooth cerebral cortex (CTX) of the rat or mouse ( NeuroNames ). See also: orbital sulci. Updated 7 Sep 2024.