Ascending ramus of lateral sulcus

The ascending ramus of lateral sulcus starts from the stem of lateral sulcus, which extends sideways between the frontal and temporal lobes on the inferior surface of the brain and reaches the outer side of the brain. At this point, the lateral sulcus divides into three branches. The first and most anterior branch is called the anterior ramus, followed by the second branch known as the ascending ramus. The ascending ramus of lateral sulcus extends upward about 2.5 cm into the inferior frontal gyrus, creating a separation between the front part called the pars triangularis and the back part called the pars opercularis (fronto-parietal operculum).