THE CEREBRUM 



489 



The caudate nucleus as it passes posteriorly, on the lateral 

 part of the?' floor of the central part of the lateral ventricle, 

 narrows very rapidly. 



The terminal vein is seen through the ependyma in the 

 groove between the caudate nucleus and the thalamus. It 

 joins the internal cerebral vein (O.T. vein of Galen) at the 

 interventricular foramen. In the same groove is placed the 

 stria terminalis a narrow band of white matter, which bends 

 downwards and disappears from view in the region of the 



Bulb of cornu 



Splenium 



Bulb of cornu 



Calcar avis 

 \ \ Tapetum 

 \ Optic radiation 

 Inferior longitudinal bundle 



FIG. 199. Frontal section through the Posterior Horns of the 

 Lateral Ventricles. 



interventricular foramen. Its fibres ultimately reach the 

 substantia perforata anterior, in which they end. 



The portion of the upper surface of the thalamus, which 

 appears in the floor of the lateral ventricle is, in great part, 

 covered by the chorioid plexus of the lateral ventricle. The 

 plexus is a rich vascular fringe which appears from under 

 cover of the sharp lateral edge of the fornix. It is con- 

 tinuous anteriorly, through the interventricular foramen, with 

 the corresponding chorioid plexus of the opposite side ; whilst 

 posteriorly, it is carried into the inferior horn of the ventricle. 

 Although the chorioid plexus has all the appearance of lying 

 free within the ventricle it is invested by an epithelial layer 



