Temporal pole anatomy and Meyer's loop. The lateral surfaces of the right frontoparietal and temporal lobes have been dissected to reveal underlying white matter and medial temporal structures.  The anterior region of the temporal horn of the lateral ventricle has been opened.  The ventromedial wall and floor of the temporal horn is formed by the hippocampal head.  Superior and medial to the hippocampal head is the amygdala; the two structures are separated by a narrow cleft known as the uncal recess.  Fibers in the optic radiation, including its anterior extension into the temporal lobe known as Meyer's loop, travel along the lateral border of the inferior horn of the lateral ventricle towards the primary visual cortex in the occipital lobe.  Fibers in Meyer's loop carry specifically information from the superior half of the visual field, hence, lesions here produce a contralateral superior quadrantinopia (pie-in-the-sky visual defect).   Dorsal to the optic radiations and forming part of the white matter of the frontal and parietal lobes, are the external capsule and superior longitudinal fasciculus. (Image courtesy of PA Rubino)