260 



THE NERVOUS SYSTEM 



bral cortex (Fig. 193). Of these, the corticobulbar tract to the motor nuclei of 

 the cranial nerves occupies the genu, and the cor tico spinal tract the adjacent 

 portion of the posterior limb. The fibers of the corticospinal tract are so ar- 



Caudate nucleus 



Frontopontine tract 

 Anterior thalamic radiation 



^Corticobulbar tract 

 'Globus pallidus 

 ^-Corticorubral tract 



- Corticospinal tract (arm) 

 -Corticospinal tract (leg) 

 -Putamen 



- Thalamic radiation (sensory fibers) 



Auditory radiation 



Thalamus 



Optic radiation 

 Fig. 193. Diagram of the internal capsule. 



ranged that those for the innervation of the arm are nearer the genu than those 

 for the leg. Accompanying the corticospinal tract are descending fibers from 

 the cortex of the frontal lobe to the red nucleus, the corticorubral tract. Those 



Coronal fibers from posterior limb of 

 internal capsule 



Coronal fibers from anterior L^ 

 limb of internal capsule 



Lentiform nucleus 



Coronal fibers from retro- 

 lenticular part of inter- 

 nal capsule 



Coronal fibers from sublenticular part 

 of internal capsule 



Anterior commissure-' 

 Ansa peduncularis'' 



Fig. 194. The lentiform nucleus and the corona radiata dissected free from the left human 



cerebral hemisphere. Lateral view. 



fibers of the thalamic radiation which run to the posterior central gyms and con- 

 vey general sensory impulses from the lateral nucleus of the thalamus are sit- 

 uated behind the corticospinal tract. The retrolenticular part of the internal 



