The calcarine sulcus is a fissure that begins slightly above the occipital pole, usually on the middle surface but at times on the side of the occipital lobe of the brain. It travels along the middle of the cerebrum between the cuneus and the lingual gyrus and is joined by the descending parieto-occipital sulcus. It continues in the lower front of the isthmus of the cingulate gyrus and splenium of the corpus callosum, where it forms the upper boundary of the parahippocampal gyrus for a short distance before it ends.