A, Left cerebral hemisphere. The pre- and postcentral gyri adjoin the central sulcus. The precentral gyrus is located behind the pars opercularis and the postcentral gyrus is located in front of the supramarginal gyrus. B, The frontal, parietal, and temporal operculi have been removed to expose the insula. The corona radiata and some of the fibers joining the internal capsule are exposed above the insula. The insular surface is composed of long and short gyri. The superior longitudinal fasciculus courses around the outer margin of the insula and lentiform nucleus. The retrolenticular part of the optic radiations are exposed behind the insula and deep to the superior longitudinal fasciculus. C, The claustrum and the posterior part of the external capsule have been removed to expose the putamen. The anterior part of the external capsule has been preserved. The uncinate fasciculus interconnects the frontal and temporal lobes. The retrolenticular part of the optic radiations is exposed behind the lentiform nucleus. The superior longitudinal fasciculus courses superficial to the optic radiations and deep to the extreme and external capsules. D, The frontal horn, body, atrium, and temporal horn of the lateral ventricle have been exposed. The fibers of the external capsule superficial to the putamen have been removed. The internal capsule courses medial to the lentiform nucleus, the outer segment of which is formed by the putamen. The lower part of the uncinate fasciculus has been removed to expose amygdala and the head of the hippocampus. The amygdala forms the anterior wall of the temporal horn. The calcar avis, overlying the deep end of the calcarine sulcus, and the bulb of the corpus callosum, overlying the fibers of the forceps major, are exposed in the medial wall of the atrium. (Images courtesy of AL Rhoton, Jr.)