Microsurgical Anatomy of the Temporal Lobe and Its Implications on Temporal Lobe Epilepsy Surgery
(a) The inferior view of the roof of the temporal horn. The roof and the lateral wall of the temporal horn are formed by the tapetum fibers of the corpus callosum, which is covered by optic radiations with the only exception of the anterior portion of the lateral wall. Optic radiations arise from lateral geniculate body as three unseperable bundles. The anterior bundle making a prominent anterior curve is referred to as the Meyer’s loop. (b) Inferomedial view of the left hemisphere. The cortical gray matter of the isthmus and the lingual, parahippocampal, and fusiform gyri have been removed. The cingulum travels inside the isthmus and parahippocampal gyrus. The fasciolar gyrus and its continuation, the subsplenial gyrus, form part of the hippocampal tail below the splenium. (c) Superolateral view of the temporal subcortical structures, the central core, and the lateral ventricular space. The insula and the underlying extreme and external capsules have been removed to expose the central core. The internal capsule course between the caudat nucleus medially and lentiform nucleus laterally. The corpus callosum forms the anterior wall and the roof of the lateral ventricle. The uncinate fasciculus (UF) and the inferior occipitofrontal fasciculus (IFOF) form the temporal stem. The UF forming the anterior part of the temporal stem interconnects the orbitofrontal cortex and the anterior part of the temporal lobe. (d) Closer view of the UF. The UF travels in the extreme and extrenal capsules and deep to the limen insula to connect the the orbitofrontal cortex to the temporal pole and the amygdala. (e) The view of the left hemisphere. The anterior and middle short gyri of the insula and the callosal fibers forming the anterior portion of the roof of the lateral ventricle have been removed to expose the central core. The lateral wall of the frontal horn is formed by the head of the caudate nucleus situated medial to the internal capsule. The lentiform nucleus formed by the putamen and the globus pallidus is located lateral to the internal capsule. (f) The fibers contributing to the lateral wall of the lateral ventricle and the atrium have been removed. The medial wall of the atrium is built by two prominences. The superior prominence, referred to as the bulp of corpus callosum, is formed by the fibers in the forceps major, and the inferior prominence, referred to as the calcar avis, is the bulge of the calcarine sulcus to the ventricular space. Globus pallidus has an external and internal parts seperated by the internal medullary lamina. The anterior commissure is located ventral to the globus pallidus. The inferior longitudinal fasciculus (ILF) connecting the anterior temporal lobe to the posterior part of the temporal lobe and occipital lobe is situated lateral to the optic radiations at the lateral wall of the temporal horn. (g) The view of the superior longitudinal fasciculus (SLF) in a left hemisphere. The SLF consists of three segments: a frontoparietal segment, a parietotemporal segment, and a frontotemporal segment, referred to as the Arcuate fasciculus providing a direct connection between the speech areas located at the inferior frontal gyrus and the posterior part of the superior temporal gyrus. AF: Arcuate Fasciculus; Ant.: anterior; Calc.: calcarine; Call.: callosum; Cap.: capsule; Chor.: choroidal; Col.: column; Coll.: collateral; Comm.: commissure; Corp. Corpus; Ext.: external; Fasic.: fasciculus; Front.-Occip.: fronto-occipital; Front.-Par.: frontoparietal; Gen.: geniculate; Glob.: globus; Hippo.: hippocampus; Inf.: inferior; Insulo-operc.: insulo-opercular; Int.: internal; Lat.: lateral; Long.: longitudinal; Mam.: mamillary; Mid.: middle; Operc.: operculum; Pall.: pallidus; Post.: posterior; Rad.: radiation; Seg.: segment; Subspl.: subsplenial; Sulc.: sulcus; Supramarg.: supramarginal; Temp.: temporal; Triang.: trianguler; Uncin.: uncinate.
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