182 



TOPOGRAPHICAL ANATOMY OF THE 



dorso-lateral and ventral surfaces. The dorso-lateral surface (facies 

 convexa), for the most part convex, is applied to the Avails of the 

 cranium. The medial surface (facies medialis), on the contrary, is 

 flattened, and much of it faces the corresponding surface of the opposite 

 hemisphere : the more posterior portion, however, faintly concave, joins 

 the rest at an angle and faces the cerebellum, from which it is separated 

 by the tentorium only. The ventral surface (basis cerebri) is irregular 

 and is formed by the olfactory and piriform lobes. 



Frontal pole. _ 



Supras3-lvian sulcus. 



Ectolateral sulcus. 



Lateral sulcus.--^'— 



Occipital pole. 



Vermis of cerebellum. ^ 



Olfactory bulb. 

 Cruciate sulcus. 



-Longitudinal fissure. 



— Transverse fissure. 

 -Hemisphere of cerebellum. 



--Medulla oblongata. 



Fig. 84. — Dorsal aspect of the brain. 



The extremities of the hemisphere are known as the frontal and 

 occipital poles (polus frontalis : polus occipitalis), of which the anterior 

 is laterally flattened, and the posterior is bluntly pointed. 



If, in the intact specimen, the hemispheres are separated as far as 

 possible by opening the longitudinal fissure, it will be found that they 

 are connected by a broad, white, commissural band, the corjnis callosum. 

 It will be observed, moreover, that the commissure does not extend to 

 either the frontal or the occipital pole of the hemisphere, and that it is 

 not placed in a horizontal plane, but slopes downwards and forwards. 



The surface of the hemisphere is sculptured by lines, known as 



