BASAL GANGLIA 



459 



it will divide the anterior part of the corpus callosum, the lamina 

 terminalis, the anterior commissure and the optic chiasma. 

 In the interval between the columns of the fornix and the corpus 

 callosum the knife should pass through the cavity between the 

 layers of the septum pellucidum. Posteriorly, the incision will 

 bisect the pineal body and its peduncle, and the upper part of 

 the lamina quadrigemina, which is still attached to the cerebrum ; 

 then it will pass through the upper part of the aquaeductus cerebri, 



Genu of corpus callosum 



Anterior horn of lateral ventricle 



Head of caudate nucleus 



Anterior limb of internal capsule 

 Cavum septi pellucidi 



Genu of internal capsule 

 Globus pallidus 



Fasciculus mamillo-thalamicus 

 Posterior limb of internal capsule 



Thalamus 



Retrolenticular part 



of internal capsule 



Tail of caudate nucleus 



Hippocampus 



Splenium 



Posterior horn of lateral ventricle 

 Stria gennari - 



Calcarine fissure .-- 



Tapetum 





Optic radiation 



Inferior longitudinal bundle 



FIG. 182. Horizontal section through the Right Cerebral Hemisphere at the 

 level of the widest part of the lentiform nucleus. 



and, ventral to the aqueduct, it will separate the cerebral 

 peduncles of opposite sides from one another. As the knife 

 passes through the base of the brain, that is, through the floor 

 of the third ventricle, from before backwards, it will divide the 

 tuber cinereum ; then it will pass between the mamillary bodies, 

 and, posteriorly, it will bisect the posterior perforated substance. 

 The massa intermedia, which unites the adjacent surfaces of 

 the thalami, will be divided as the knife passes through the 

 cavity of the third ventricle. After the division has been made 

 the dissector should note the positions and relations of the 



