BOUNDS OF LATERAL VENTRICLE. 201 



losum (a), descends in a curved direction in the temporo-sphenoidal lobe, 

 with the concavity of the bend turned inwards. 



For the purpose of examining its boundaries, the ventricle may be di- 

 vided into an upper or horizontal, and a lower or descending part. 



The upper or horizontal portion reaches from the frontal to the occipital 

 lobe, and is shaped like the italic letter/. 



Fig. 63. 



VIEW OF THE LATERAL VENTRICLES; ON THE LEFT SIDE THE DESCENDING CORNC is LAID 

 OPEN. (From a cast iu a museum of University College, London.) 



a. Kemains of the corpus callosum. g. Optic thalatnus. 



b. Septum lucidum, iuclosiug the small space h. Choroid plexus. 



of the fifth ventricle. i Hippocampus minor. 



c. Fornix. k. Eminentia collat^ralis. 



d. Posterior cms or tniaof the foruix. /. Hippocampus major. 



e. Corpus striatum. o. Digital fossa. 

 /. Ttenia semicircular! s. 



The roof is formed by the corpus callosum. The floor is irregular in 

 outline, and presents from before backwards the following objects : first, 

 a small piece of the under part of the corpus callosum ; next, a large, gray 

 body, the corpus striatum (e) ; behind this, the large white projection, 

 named optic thalamus (g} ; and between the two last bodies is a white 

 band (/), t&nia semicircularis. On the surface of the optic thalamus is a 

 vascular fold of the pi a mater (/*) the plexus choroides, together with 

 the thin white half of the fornix (c). Close behind the thalamus is the 

 beginning of a projection (hippocampus major) (e), in the floor of the de- 

 scending part of the lateral ventricle ; and in the posterior cornu is an 

 elongated eminence, the hippocampus minor (/). 



