Subtemporal Approach to the Medial Temporal Region. A, Coronal section through the right temporal lobe. The temporal horn is approached through the occipitotemporal sulcus on the basal surface (red arrows). The medial disconnection is directed through the choroidal fissure (red dotted line) medially and the amygdala, uncus, hippocampus, and parahippocampal and fusiform gyri are removed (horizontal blue lines). B–F, Stepwise cadaveric dissection demonstrating the subtemporal transoccipitotemporal sulcus approach. B, The right temporal lobe has been exposed from the sylvian fissure to the floor of the middle fossa. If the patient has a bulky temporal muscle, it may be necessary to divide the zygomatic arch to fold the temporalis muscle downward to decrease the temporal lobe retraction (pretemporal zygomatic approach). C, The inferior temporal gyrus has been elevated gently, cerebrospinal fluid has been aspirated from the perimesencephalic cisterns, and the occipitotemporal sulcus has been opened. D, The temporal horn is exposed through an incision directed upward and medially through the occipitotemporal sulcus. The choroid fissure will be opened on the side of the fimbria of the fornix, not on the thalamic side, to expose the structures inside ambient cistern. E, The choroidal fissure has been opened and the incision extended forward into the amygdala along Wen’s line, which extends from the level of the carotid bifurcation to the level of the entry of the oculomotor nerve into the roof of the cavernous sinus. F, The uncus, anterior portion of the hippocampus and parahippocampal and fusiform gyri, and all but the upper part of the amygdala have been removed, exposing the contents of crural and ambient cisterns. G, Preoperative, contrast-enhanced magnetic resonance imaging scan of a 64-year-old man harboring a metastatic lung tumor in the anterior part of the left medial temporal lobe. H, Postoperative magnetic resonance imaging scan after a subtemporal transoccipitotemporal sulcus approach and lesion resection. (Images courtesy of AL Rhoton, Jr.)