part of frontal lobe middle frontal gyrus 2010-10-08T09:09:10Z BTO:0004834 BrendaTissueOBO It makes up about one-third of the frontal lobe of the human brain. A gyrus is one of the prominent bumps or ridges on the surface of the human brain. The middle frontal gyrus, like the inferior frontal gyrus and the superior frontal gyrus, is more of a region than a true gyrus. The borders of the middle frontal gyrus are the inferior frontal sulcus below; the superior frontal sulcus above; and the precentral sulcus behind. mgr