Superior lateral view of left subcortical nuclei. The frontal lobe has been resected between the premotor cortex and precentral gyrus. The lentiform nucleus is comprised of the putamen laterally and globus pallidus medially. The internal capsule divides the lentiform nucleus from the caudate nucleus anteromedially and the thalamus posteromedially. The insula can be visualized with the removal of the frontal lobe as it lies deep within the lateral fissure (of Sylvius). The corpus callosum forms the roof of the lateral ventricle and on its floor is a choroid plexus that produces cerebrospinal fluid. The foramen of Monro communicates the lateral ventricle with the midline third ventricle.  (Image courtesy of AL Rhoton, Jr.)