THE CEREBRUM 



491 



produced by a superjacent collection of grey matter, termed 

 the amygdaloid nucleus. The stria terminalis and the greatly 

 attenuated and expanded tail of the caudate nucleus are both 

 prolonged into the inferior horn, and are carried anteriorly in 

 its roof to the amygdaloid nucleus. 



On the floor of the inferior horn the dissector will note 

 the following parts: (i) the hippocampus; (2) the chorioid 

 plexus; (3) the fimbria; and (4) the eminentia collateralis. 



Hippocampus (O.T. Hippocampus Major). This is over- 

 lapped by the chorioid plexus, which must be turned aside. 



Stria terminal 



Chorioid plexus 



Caudate nucleus ', 



Inferior cornu of lateral ventricle \ \ 



Optic tract 



| Fimbria 



Subthalamic body 

 ! Basis pedunculi 

 ! .' Red nucleus 



Collateral eminence ! Pia-mater 



Collateral fissure Cerebellum 



FIG. 200. Frontal Section to show relations of Inferior Cornu of 

 Lateral Ventricle. (Part of Fig. 217 enlarged. ) 



It is a prominent elevation on the floor of the inferior horn 

 of the lateral ventricle, and is strongly curved in conformity 

 with the course taken by the horn in which it lies. It pre- 

 sents, therefore, a medial concave margin and a lateral convex 

 margin. Narrow posteriorly, it enlarges as it is traced 

 anteriorly, and it ends, below the amygdaloid tubercle, in a 

 thickened extremity, the pes hippocampi. The surface of the 

 pes hippocampi is marked by some faint grooves which inter- 

 vene between a number of ridges called the hippocatnpal 

 digit at ions. The hippocampus is the internal elevation which 

 corresponds to the hippocampal fissure on the exterior of the 

 wall of the ventricle. 



Fimbria (Hippocampi). The fimbria is a narrow but very 



