NEUROLOGY 





anterior, raised part, the culmen or summit, and a posterior sloped part, the clivuj; ; 

 the quadrangular lobule is similarly divided. The culmen and the anterior parts 

 of the quadrangular lobules form the lobus culminis; the clivus and the posterior 

 parts, the lobus clivi. 



The Folium Vermis and Superior Semilunar Lobule. The folium vermis (folium 

 cacuminis; cacuminal lobe} 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 (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. 



Ala lobuli centralis Flocculus 



Postnodular fissure 



Ant. medullary velum 

 Lobulus centralis 



Horizontal sulcus 



Tuber vermis 

 FIG. 703. Under surface of the cerebellum. (Schafer. 



The under surface of the cerebellum (Fig. 703) presents, in the middle line, the 

 inferior vermis, buried in the vallecula, and separated from the hemisphere on either 

 side by a deep groove, the sulcus valleculae. Here, as on the upper surface, there 

 are deep fissures, dividing it into separate segments or lobules ; but the arrangement 

 is more complicated, and the relation of the segments of the vermis to those of the 

 hemispheres is less clearly marked. The inferior vermis is subdivided from before 

 backward, into (1) the nodule, (2) the uvula, (3) the pyramid, and (4) the tuber 

 vermis; the corresponding parts on the hemispheres are (1) the flocculus, (2) the 

 tonsilla cerebelli, (3) the biventral lobule, and (4) the inferior semilunar lobule. The 

 three main fissures are (1) the postnodular fissure, which runs transversely across 

 the vermis, between the nodule and the uvula. In the hemispheres this fissure 

 passes in front of the tonsil, crosses between the flocculus in front and the biventral 

 lobule behind, and joins the anterior end of the horizontal sulcus. (2) The pre- 

 pyramidal fissure crosses the vermis between the uvula in front and the pyramid 

 behind, then curves forward between the tonsil and the biventral lobe, to join 

 the postnodular fissure. (3) The postpyramidal fissure passes across the vermis 

 between the pyramid and the tuber vermis, and, in the hemispheres, courses 

 behind the tonsil and biventral lobules, and then along the lateral border of the 

 biventral lobule to the postnodular sulcus; in the hemisphere it forms the anterior 

 boundary of the inferior semilunar lobule. 



The Nodule and Flocculus. The nodule (nodulus vermis; nodular lobe), or anterior 

 end of the inferior vermis, abuts against the roof of the fourth ventricle, and can 



