26 



THE NERVOUS SYSTEM 



The medial wall of the lateral ventricle is formed, anteriorly, 

 by the septum pellucidum, and, posteriorly, by the union of 

 the fornix with the corpus callosum. The interventricular 

 foramen (of Monro), which connects the lateral with the third 

 ventricle, is situated on this wall behind the column (anterior 



FIG. 15. The Tela Chorioidea (velum interpositum) viewed from above. 



1. Tela chorioidea. 5. Septum pellucidum (cut). 



2. Chorioid plexus. 6. Vein of corpus striatum. 



3. Thalamus. 7. Stria terminalis. 



4. Caudate nucleus. 8. Great cerebral vein (of Galen). 



9. Internal cerebral vein. 



pillar) of the fornix and in front of the anterior extremity of 

 the thalamus. 



When the corpus callosum, the septum pellucidum, and 

 the fornix are completely removed, the cavities of the two 

 lateral ventricles are thrown into one and the tela chorioidea 

 (velum interpositum) is exposed in its entirety (Fig. 13). It 



