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ANATOMY OF THE CENTEAL NEEVOUS SYSTEM. 



posterior limb of the internal capsule, all the sensory fibers and the fibers 

 connected with the nerves of special sense. Besides these, moreover, there 

 are here fonnd coronal fibers to the thalamus from the cortex of the tem- 

 poral and occipital lobes, and the temporo-occipital tract to the pons. The 

 following figure shows diagrammatieally the relative positions of the sepa- 

 rate tracts composing the internal capsule. 



All of these fiber-masses, therefore, converge from the cortex toward the region 

 lying lateral to the thalamus. A part of them enters the thalamus (corona radiata 

 of the thalamus) ; another part — and that the larger — passes under the thalamus, 

 where it ends in ganglia or passes on farther down to the spinal cord. Lesions that lie 

 in the centrum semiovale must, therefore, involve part of the fibers of the corona . 



Fig. IBS. — Diagram of the internal capsule, in which the location of most 

 of the tracts of fibers which compose it is indicated by their respective names. 

 Extremitaten mot. Bahti, Motor tract to the extremities. Fasern aus Nucleus 

 Gaudatus, Fibers from nucleus caudatus. Fasern aus N. Lentiformis, Fibers from 

 nucleus lentiformis. Frontale Briickevljalni, Frontal cortical tract to the pons. 

 Opticusfasem, Optic fibers. Seusorische Fasern, Sensory fibers. Stabkranz des 

 Thalamus, Corona radiata of the thalamus. Stahlcrnnz zum Thalamus, Coronal 

 fibers to the thalamus. Temporo-occipitale Briiokenbahn, Temporo-occipital cor- 

 tical tract to the pons. 



radiata. But by no means always do they produce symptoms which lead us to 

 suspect an interruption in the conducting pathway from the cortex to the periphery. 

 This is probably on account of the fact that the coarser lesion-symptoms which may 

 be detected by our present means of diagnosis arise only whenever the entire tract 

 involved is destroyed. It appears that small remnants are sufficient to conduct 

 voluntary impulses from the cortex to the deeper parts, or to convey sensory im- 

 pressions from the periphery to the cortex. 



Lesions, in particular, that do not lie in the medullary substance under the 



