424 PTTYSTOLOCJY 



hemispheres, from which it is separated bv the velum interpositum 

 and by the ependyma, the epithelium completm- flu- inferior wall of 

 the lateral ventricle in this region. It consists of three masses of 

 grey matter the anterior nucleus, the lateral nucleus (the lar-rst 

 of the three), and the mesial nucleus. Its outer surface is in contact 

 with the layer of nerve fibres formed by the crusta of each cms cerebri 



;|S if di\er-e, from Its lel|o\\ to |KISS II)) Illto the Cerebral hemispheres. 



Into this layer, * the internal capsule,' fibres proceed from nil 

 parts of the thalamus to pass to the cerebral oortez, The anterior 



FlO. 191. Transverse section llncii^li upper part ol nii.l i.rain. 

 Tli, tlialamiiH ; />/'*, luacliium supcrioi ; cf/x, antrritir (or sii])cri(>r) rurpus 

 quadrigCiniiniin ; <-</i, <-t/< , nit.-iii.il ami i-xlrrnal L'riiiciilal r Ixulics ; /. lilld ; 

 . .M|ih dii. t ; /i/. posterior lon^itiidi mi I I MI IK Hi- ; /', raplie ; ///. t liinl nerve ; 

 nlll, its inn I. -11., ; Ipp, posterior -perforated space ; *//, sn list an) ia in 

 (/, crusta; //. oplic h.irl ; .!/, niediil l.i i \ ..-nli.- ..I lli<- In-niisplici r ; 

 //c, nucleus caudal us ; .s7. si i ia Icriuinalis. 



cxtnMiiity of the t li;il;imus. known as the anterior tubercle, forms 8 

 inarkctl project ion into t lie lateral venlriclr. In tVont of this, the 

 foramen of Mourn leads from the third vent rule into the lateral 

 ventricle. This foramen is bounded anteriorly l>y a strand of fibres, 

 known as the ' anterior pillar of the formx." which lies just behind the 

 anterior commissure and forms a conspicuous feature in the anterior 

 part of the lateral wall of the third ventricle. It passes in the wall 

 down to the corpus niammillare. Krom the corpus inammillare a 

 well-marked bundle of fibres passes up into the optic thalamus to end 

 round the large cells in the anterior nucleus of the thalamus. The 

 posterior extremity of the thalamus forms a definite prominence, 

 the imlrimir. To the outer and back part of the pnlvinar two bodies 



