Right pterional approach to frontal, parietal, and temporal lobes and orbit. For orientation, anterior is toward the upper left corner of the image, superior is toward the bottom border of the image. An osteotomy through portions of zygomatic, frontal, parietal, and temporal bones provides exposure to lateral orbital contents and the anterolateral cerebral hemisphere. The frontal and parietal lobes of the cerebrum are separated from the temporal lobe by the lateral sulcus or Sylvian fissure. Shown coursing in this fissure is the superficial middle cerebral vein or Sylvian vein. It is a member of the superficial cerebral vein family of vessels. It curves anteriorly around the temporal lobe to drain into the sphenoparietal or cavernous sinuses. On the upper lateral surface of this hemisphere are superior cerebral veins that will drain to the midline superior sagittal sinus. The central sulcus separates the precentral gyrus (primary motor cortex) of the frontal lobe from the postcentral gyrus (primary somatosensory cortex) of the parietal lobe. Respective, pre- and postcentral sulci lie anterior and posterior to these gyri. On the lateral surface of the temporal lobe, the superior temporal sulcus (the first sulcus inferior to the lateral sulcus) separates the superior and middle temporal gyri, while the inferior temporal sulcus separates the middle temporal gyrus from the inferior temporal gyrus. (Image courtesy of AL Rhoton, Jr.)