424 



THE BRAIN 



continuous white area which consists of the corpus callosum 

 and the medullary centres of the two hemispheres. 



Corpus Callosum. The corpus callosum is the great 

 transverse commissure of the cerebrum. It is placed nearer 

 the anterior than the posterior end of the brain, and it unites 



Cingulum 



Fibres of corona radiata 



Intersection of C 

 callosal and corona I 

 radiata systems of| 

 fibres 



Corpus callosum 



Frontal fibres 

 Genu 



- Cut surface 



Transverse fibres 

 , of corpus 

 callosum 



v Inferior longitu- 

 dinal fasciculus 



Cingulum 



Splenium 



'} 



'. rTapetum 

 P'orceps major 

 Stria longitudinalis medialis 



FIG. 1 6 1. The Corpus Callosum exposed from above and the right half 

 dissected to show the course taken by the fibres. 



the medial surfaces of the two cerebral hemispheres throughout 

 very nearly a half of their antero-posterior length (Fig. 161). 



Its upper surface, which forms the floor of the central part 

 of the longitudinal fissure, is convex antero-posteriorly and 

 concave from side to side. In the posterior part of its extent 

 it is touched, in the median plane, by the falx cerebri ; 

 anteriorly, that fold of dura mater does not pass so deeply into 

 the fissure. On each side of the fissure the corpus callosum 

 is covered by the gyrus cinguli (O.T. callosal gyms). The 



