634 



THE NEKVOUS SYSTEM. 



backwards from the superior and posterior part (i.e. the convexity) of the primitive 

 cavity. 



Cornu Anterius. The anterior horn forms the foremost part of the cavity, and 

 extends in a forward and lateral direction in the frontal lobe. When seen in 

 frontal section (Fig. 562) it presents a triangular outline, tKe floor sloping upwards 

 and laterally to meet the roof at an acute angle. It is bounded in front by the 

 posterior surface of the genu of the corpus callosum ; the roof also is formed by the 



Corpus callosum 

 Cavum septi pellucidi 



Foramen interventriculare 

 Caudate nucleus 

 Thalamus 



Chorioid plexus 



Stria terminalis 



Trigonum collateral 



Hippocampus 



Fimbria ; 



Occipital part of the radiation of the corpus callosum 



Calcar avis 



Bulb of the cornu 



Hippocampus 

 Crus of the fornix 



Body of the fornix 



FIG. 563. DISSECTION, to show the fornix and lateral ventricles ; the body of 'the corpus callosum 



has been turned over to the left. 



corpus callosum. The medial wall, which is vertical, is formed by the septum 

 pellucidum; whilst the sloping floor presents a marked elevation or bulging, 

 viz., the smooth, rounded, and prominent extremity of the pear-shaped caudate 

 nucleus. 



Pars Centralis. The central part or body of the cavity is likewise roofed by the 

 corpus callosum. On the medial side it is bounded by the posterior part 'of the 

 septum pellucidum which attaches the fornix to the inferior surface of the corpus 

 callosum. On the lateral side it is closed, as in the case of the anterior horn, by the 

 meeting of the floor and the roof of the cavity. On the/oor a number of important 



