CEREBELLUM 



485 



to the inferior quadrigeminal body, the small trochlear nerves 

 emerge. 



Certain of the sulci which traverse the surface of the 

 cerebellum, deeper and longer than the others, map out 

 districts which are termed lobes. The most conspicuous of 

 all the clefts is the horizontal sulcus. 



Sulcus Horizontalis Cerebelli. The horizontal sulcus 

 begins anteriorly, where its lips separate from one another 

 to enclose the large brachia pontis, and it passes round the 



Pons 



Mesencephalon 



Central lobule 



Culmen monticuli 



Anterior crescentic lobule 



Posterior crescentic lobule 



Superior semilunar 

 lobule 



Declive monticuli 



Folium vermis 



Inferior semilunar lobule 



Tuber vermis 

 Posterior notch 



FIG. 196. Upper surface of the Cerebellum. 



circumference of the cerebellum, cutting deeply into its lateral 

 and posterior margins. By means of the horizontal sulcus 

 the cerebellum is divided into an upper and a lower part, 

 which may be studied separately. 



Lobes on the Upper Surface of the Cerebellum. It has been noted 

 already that the upper surface of the vermis superior is subdivided. The 

 divisions, commencing at the anterior end, are: (i) the lingula ; (2) the 

 central lobule ; (3) the culmen monticuli ; (4) the declive monticuli ; (5) the 

 folium vermis. With the exception of the lingula, each part is continuous 

 on each side with a corresponding district on the upper surface of the hemi- 

 sphere, and forms with those districts a cerebellar lobe. Thus, the central 

 lobule is prolonged laterally on each side in an expansion called the ala 



