The term posterior supraprincipal dimple refers to a small vertical depression variably present on the dorsal surface of the frontal lobe of the macaque. It is located anterior to the superior limb of the arcuate sulcus ( Walker-1940 ) and posterior to the anterior supraprincipal dimple ( Paxinos-2004 ). While some authors refer to it as the sulcus frontalis superior, they do not consider it homologous to the superior frontal sulcus ( Bonin-1947 ). It has no equivalent in rodents.