110 



Cerebellum. 



451. The Cerebellum, view from below. Natural size. 



At tlie base of the brain (Fig. 450) there are further seen : 



c) The Tuber cinereum and the Infmidibulum. The Tuber cinereum is 

 situated behind the chiasma and forms part of the floor of the third 

 ventricle. From the middle of its under surface a hollow conical 

 process, the Infimdibulum, is continued downwards and forwards. 



d) The pituitary body or Hypophysis ccrcbri, situated in the 

 Sella turcica. It is a small vascular mass, consisting of an anterior and 

 a posterior lobe, which are separated from one another by a fibrous lamina. 



e) The Corpora albicantia or inamniillaria s. Globuli mcdullares, two 

 small, round, white masses, each about the size of a pea. 



f) The posterior perforated space, Snbstantla perforata 

 posterior, placed in the angle between both Crura ccrcbri, composed of 

 grey matter, is continued anteriorly into the Tuber cinereum. 



g) The Crura cercbri s. Pedunculi cercbri, two thick, cylindrical bundles 

 of white matter, which emerge from the anterior border of the "pons, 

 and diverge as they pass forwards and outwards to enter the under 

 part of either hemisphere. In a transverse section, each Cms cerebri is seen 

 to consist of a lower, flat bundle of fibres, the proper Pedunculus s. Caudex, 

 which is hollowed out for the upper, larger bundle, the Tcc/mentum caudkis ; 

 between both is a mass of dark grey matter, the Substantia nigra peduncuU. 



The two hemispheres of the cerebellum are connected with each 

 other by the Pons Varolii, and behind the pons, between the two hemi- 

 spheres of the cerebellum is the Jfedutta ollonfjata. 



The Pons Varolil or Tuber anmdare presents an under (anterior) 

 and an upper (posterior) surface, an anterior and a posterior border. 

 On the middle of its under surface is seen a longitudinal groove, Sidcus 

 basilaris, which lodges the basilar artery. At the anterior border the Crura 

 cercbri diverge ; at the sides are the middle peduncles of the cerebellum 

 or Processus cercbelli ad pontem, which connect the pons with the hemi- 

 spheres of the cerebellum. The posterior border of the pons is in relation 

 with the Medulla oblonyata. 



