827 



struct urcs of the floor of the anterior and ventral portion of the third ventricle. 

 The area extends anteriorly from the corpora niaminillaria in the interpeduncular 

 fossa, and includes the tuber cinereum and hypophysis liehind the optic chiasma, 

 and some of the anterior perforated substance in front of it. 



The most anterior portion of the third ventricle is in the form of a ventral ex- 

 tension. The wall of this portion is almost wholly non-nervous and quite thin, 

 and thus the cavity of the ventricle js lint thinly separated from the exterior of the 

 brain. The front portion of this wall is the lamina terminalis and in the ventri- 

 cular side of the dorsal part of this lamina the anterior commissure of the brain 



Fin. 616. VENTKAL ASPECT OK BKAIX-STK.M I\< LI DIM; MAMMILLAKY AND OPTIC PORTION* 



OF TI1K llVl-OIHAI.AM! B, 



IS8VLA 



Ill.l'AfTilliY TRACT 

 llYl'al-IDSIS 



ANTERIOR 



l'i:i;rai:.t n:n - . 



K OI-THTN (II) 

 ,OfIK TH.ICT 



- TCJII:/: fi\i-:i:i-:r.\i 



\. OCl l.li.MO- 

 ,_- Taint's (III ! 

 LATERAL 



1:11/1} 



un 



-~,, A'. 7v;/';/:.i//.\T.v 



(-V. I'.) 



("') 



A'. ASDVCEN& 



(i/i 

 lIKM-IIIf.M 



---- .V. l--.tflM.ls 



(\'ll) 

 .'.v l.\TKl:MKlll.\ 



.V. Afl'STIfl's ( fill) 



. 



ll Kl s (I \ 



s (.IV) 

 TI/ accrstory) 



is apparent. The optic chiasma lies across and presses into the lower portion of 

 the lamina terminalis, and in so doinsr produces an anterior recess in the cavity of 

 the ventricle known as the optic recess. The posterior and most evident part of 

 this portion of the wall of the third ventricle bulges slitrhtly, giving the outward 

 appearance known as the tuber cinereum, and the cavity bounded by this termin- 

 ates in the infundibular recess. 



The tuber cinereum then is a hollow, conical projection of the floor of the third 

 ventricle, between the corpora mainmillaria and the optic chiasma. Its wall is 

 continuous anteriorly with the lamina terminalis and laterally with the anterior 

 perforated substance. 



