806 



THE NERVOUS SYSTEM 



The superior semilunar lobe [lobulus semilunaris superior] (postero-superior 

 lobe) of each hemisphere lies between the horizontal and the posterior semilunar 

 fissures. It largely composes the outer border of the cerebellum, and, therefore, 

 is the longest of the lobes. 



The adjacent surface of the hemispheres, because of the frequently less com- 

 plete development of the anterior semilunar fissure, is sometimes referred to as the 

 quadrangular lobe, with its posterior and its anterior portions. On the other 

 hand, especially when the anterior semilunar fissure is well marked, this area may 

 be divided into— (1) the posterior semilunar lohe, between the posterior and 

 anterior semilunar fissiues, and (2) the anterior semilunar lohe, anterior to the 

 anterior semilunar fissure (fig. 635). 



Anterior to the quadrangular lobe on each hemisphere is the ala of the 

 central lobule, bounded by the postcentral and the precentral sulcus. Anterior 

 to this, on the anterior margin of the hemisphere, is the vinculum lingulae, 

 a slender process continuous with the lingula of the vermis (fig. 658). 



Fig. 634. — Median Section Through Cerebellum and Brain-stem. (Allen Thompson, 



after Reichert.) 

 1. culmen monticuU; 2, superior semilunar lobe; 3, inferior semilunar lobe; 4, slender lobe; 



5, biventral lobe; 6, tonsil. 



Massa intermedia 

 Thalamus 



Epiphysis (pineal body) 

 Corpora quadrigemina 



Declive r-T»».J''^-i^ ' 



Cerebral peduncle 



Aquaeductus cerebri (Sylvii) 



Stria medullaris thalami 



Third ventricle 

 Column of fornix 

 Anterior commissure 



Lamina terminalis 



Tuber cinereum 

 Recessus infun- 



dibuli 

 Hypophysis (pit- 

 uitary body) 



Uvula of 



vermis 



Pyramid 



of vermis 



Fourth ventricle 



Tela chorioidea of fourth ventricle 



Medulla oblongata 



The superior aspect of the vermis, the superior vermis, because of the fusion of 

 the hemispheres, is, for the most part, a slight ridge, the monticulus (fig. 635), 

 instead of a depression. However, in the posterior portion of the dorsal surface the 

 depression of the posterior notch begins, and here the horizontal and the posterior 

 semilunar fissures approach each other so closely that the corresponding sub- 

 division of the vermis is seldom more than a single folium, the folium vermis 

 (cacuminis) . 



The monticulus proper is divided into an inferior lobule, the declive, and a 

 superior lobule, the culmen. These appear as continuations across the mid- 

 line of the posterior and anterior semilunar lobes of the hemispheres, and are 

 separated by the corresponding fissures (fig. 635). 



At the extreme anterior part of the superior surface and in the bottom of che 

 anterior cerebfillar notch lies a more definitely defined portion of the vermis. 

 This is the central lobule (fig. 635). It is broadened laterally into two pointed 

 wings, the alw of the central lobule, the folia of which, if present, are parallel with 

 those of the anterior semilunar lobes and separated from them by the post- 

 central sulcus. 



If the anterior margin of the central lobule be lifted, the lingula cerebelli 



