The term frontomarginal sulcus (fms) refers to a superficial feature of the human frontal lobe (FLB). It is a cleft on the orbital surface very near the frontal pole (frp) that separates the frontomarginal gyrus (FMG) from the middle frontal gyrus (MFG) ( Ono-1990 Mai-1997 ). It is a topological feature not found in the macaque, rat or mouse ( NeuroNames ). Updated 5 Sep 2024.