Folium of 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.

Laterally, it expands in either hemisphere into a considerable lobule, the superior semilunar lobule, which occupies the posterior third of the upper surface of the hemisphere, and is bounded below by the horizontal sulcus.