884 



THE NERVOUS SYSTEM 



The hypothalamic nuclues (fig. 698), or body of Luys, is the principal nucleus of 

 termination of the medial lemniscus, the great sensory spino-cerebral pathwayl 

 It is a biconvex plate of grey substance situated on the basal aspect of the latera. 

 and anterior nuclei of the thalamus, and between these and the basis of the cerebral 



Fig. 696. — Horizontal Sections of the Prosencephalon through the Thalamus and 



Corpus Striatum. 

 The plane of the section of the left hemisphere splits the medullary stria of the thalamus and 



is about 15 millimeters superior to the plane through which the rieht hemisphere is cut. 



(After Toldt.) 



Trunk of corpus callosum 

 Septum pellucidum 



Body of fornix 



Genu of corpus callosum 



Anterior cornu of lateral ventricle 

 Head of caudate nucleus 

 ' ^ — •' Column of fornix 



Internal capsule 



\ Island of Reil 

 \/~ (insula) 



X, \y External capsule 

 b//^ Putamen 



Inferior cornu of 

 lateral ventricle 



Chorioid glomus 



Occipito- 

 thalamic 

 radiation 



Splenium of corpus callosum 



Posterior cornu of lateral 

 ventricle 



Calcarine fissure 



peduncle, or rather tlie substantia nigra, which is spread upon the dorsal surface 

 of the peduncle, and which, tliough greatly diminished, extends into the hypo- 

 thalamic region. The hypothalamic nucleus presents a brownish-pink colour 

 in fresh material, due to pigment in its cells and to its abundant blood capillaries. 



It contains the cell-bodies of the neurones of the third order in this pathway, those of the 

 first order beinR situated in the spinal gnnglia, and those of the second order in the nuclei of the 

 fasciculus Kracilis and fasciculus cuiicatus. It is enclosed by a thin capsule of white substance, 

 Bome of the fibres of which seem to dc'cussato with those of the opposite side in the floor of the 

 third ventricle, above and just bcshind tlie region of tlie corpora mammillaria. By far the greater 

 part of the fibres arising from the nucleus join the internal capsule, and through it ascend to 



