CHAPTER XXIV 

 THE CEREBELLUM 



The cerebellum is situated in the inferior fossae of the occipital bone 

 eneath the posterior lobes of the cerebrum, from which it is separated by the 

 ntorium cerebelli, a semilunar fold of the dura mater. It is partially 

 ivided into hemispheres by a longitudinal fissure, more apparent on the 

 iferior surface, though united by a central lobe, the vermiform process, 

 ach hemisphere is connected with the cerebrum, the pons, medulla, and 

 Dinal cord by three bundles of nerve-fibers known respectively as the superior, 

 liddle and inferior peduncles. The surface of the cerebellum presents a 

 eries of lobes and fissures of which the former have received more or less 

 anciful names. A section of the cerebellum shows that it is composed 

 f gray matter externally and white matter internally. The general 

 ppearance presented on section is shown in Fig. 255. 



Structure of the Gray Matter .-The gray matter consists mainly of 

 lerve-cells of varying size and shape, which are arranged in two layers: 

 iz an outer or molecular and an inner or granular. 



The molecular layer consists of stellate and multipolar cells of small 



ize from which dendrites and axons pass horizontally and vertically 



anular kyer consists, as its name implies, of granular-shaped cells and 



rTe stellate cells These cells are characterized by the possession of den- 



^ Sd axoS! the course and relation of which have not been clearly 



determined^ mo lecular layer presents a series of large cells 



r JnallvTscribed by Purkinje and known by his name From the outer 

 nl nfL r e ll body one or more dendrities emerge which soon divide and 



