folium vermis folium vermis the folium vermis is a short, narrow, concealed band at the posterior extremity of the vermis, consisting apparently of a single folium, but in reality marked on its upper and under surfaces by secondary fissures. folium (vermis)upper surface of the cerebellum.identifiersneuronames675ta98a14.1.07.206ta25828fma83889anatomical terms of neuroanatomy laterally, it expands in either hemisphere into a considerable lobule, the superior semilunar lobule (lobulus semilunaris superior; postero-superior lobules), which occupies the posterior third of the upper surface of the hemisphere, and is bounded below by the horizontal sulcus. the superior semilunar lobules and the folium vermis form the lobus semilunaris. additional images cerebellum. superior surface. cerebellum. superior surface.