446 



THE BRAIN 



another, and the corpora quadrigemina of the mid-brain lie 

 between them, on a lower plane. Each thalamus presents a 

 small anterior extremity and a large posterior extremity, and 

 four surfaces. The inferior and lateral surfaces are in apposi- 

 tion with, and, indeed, directly connected with adjacent parts. 

 The superior and medial surfaces are free. 



The lateral surface of each thalamus is applied to a mass 



Cut surface of genu 

 of corpus callosum 



Genu of corpus callosum 



Cavum septi pellucid i- - 



For nix 



Anterior commissure i~_ 



i 

 Massa intermedia 



Groove on thalamus ,J 

 for fornix 



Posterior commissure ,-'' M 



Trochlear nerve 



Brachium pontis - 



Corpora quadrigemina 



Brachium conjunctivum 



- Septum pellucidum 



- Caudate nucleus 



-- Right column of fornij 



__'. _ Anterior tubercle of 



- \ thalamus 



r ~"y Vena terminalis 

 & ~* "" Ventricle in. 

 1 Taenia thalami 



" Trigonum habenulae 

 'Pulvinar 



Stalk of pineal body 

 Pineal body 



Lingula of cerebellum 

 'Medulla oblongata 



FIG. "176. The two Thalami and the Third Ventricle as seen from above. 



of white matter, termed the internal capsule, which is composed 

 largely of fibres from the basis pedunculi of the mid-brain (Fig. 

 1 8 8). The inferior or ventral surface of the thalamus rests 

 chiefly upon the subthalamic region, which is the prolongation 

 upwards of the tegmental part of the pedunculus cerebri. The 

 relation, therefore, which the thalamus presents to the upward 

 continuation of the pedunculus cerebri is very intimate. 



The superior surface of the thalamus is free. On the 

 lateral side it is bounded by the groove which inter- 



