THE INTERNAL CAPSULE. 



717 



striatum consists of an intra-ventricular part, the caudate nucleus ; and an extra- 

 ventricular part, the lenticular nucleus. The lenticular nucleus consists of three 

 parts, best seen in a vertical section (fig. 501, 1, 2, 3), with white matter between 

 them, the striae medullares. The anterior limb of the internal capsule sweeps 



Septum lucidum 

 Columnae fornicis 



Corpus striatum. 

 Stria terminal: 



Thalamus opticus 



Biachiuni o^njunc 

 tivum anticum. 

 Pedunculus cerebri 



" ad corpora 

 quadrige- 

 mina. 

 ad medullam 

 oblongatam 



Crus 



oerebelli 



adpontem 



Corau anticum. 



Caput nuclei caudati. 



Capsula interna 

 (anterior limb). 



Capsula externa. 



Island of Reil. 



Nucleus lentiformis. 

 Olaustrum. 



Capsula interna 

 (posterior limb). 

 - Thalamus opticas. 



Corpus genicula 

 tuui niediale. 



Caui'ate nucleus 



Hippocampus. 



Funiculus cuneatus 

 Funiculus gracilis. 



Fig. 500. 

 Human brain, with the hemispheres removed by a horizontal incision on the right side. 4, 

 trochlear ; 8, acoustic nerve ; 6, origin of the abducens ; F, A, L, position of the pyramidal 

 (motor) fibres for the face, arm, and leg ; S, sensor}- fibres. 



between the caudate and lenticular nucleus, while the posterior segment lies between 

 the optic thalamus and the lenticular nucleus (fig. 500). External to the first 

 division of the lenticular nucleus is the external capsule (figs. 500, 501), whose 

 function is unknown. External to this is the claustrum, whose function is also 



