356 



ANATOMY IN A NUTSHELL. 



I 



embryonic and so transitory, and have other names when matured They are 

 called anterior, middle, and posterior, corresponding to the fore-brain, mid- 

 braiD ^d hind-brain. They are pmnitive structures and become the ven- 

 tricles of the brain. The three commonly form five by the subdivision of 



' Tbe septum lucidum is the median partition of the lateral ventricles of the 

 ,„,„,. ^dosing the camera, pseudocele, or so-called fifth ventricle. Also called 

 ,,, septum pellucidum, (2) septum medium, (3) septum ventnculorum, (4) 

 ventricular septum. (5) septum medullare tnangulare. 



The fornix is an arch. In the human brain it consists of two Longitudinal 

 bundles of fibres, one on each side, which rise from the corpora albicantia pass 

 up. as the anteriob pillars of the fornix in front of the foramina of Monro 



PLATE CLXXVI. 



ARR SUPPl.kD BY M D3LE CEREBRAL ARTERY. 



Showing Blood Supply on Mesial Surface, (Sagittal Section^f Brain). 

 and behmd the anterior commissure, these somewhat flattened and in apposi- 

 tion to each other, arch backward beneath the corpus callosum and above the 

 velum interpositum, forming the body of the fornix and then diverge toward 

 the back pari of die corpus callosum, to turn down, as the posteriok pillars 

 f the fornix (crura fornices), into the floor of the descending cornua of the 

 lateral ventricles, where their free edges form the fimbriae. 



The fimbria is a narrow band of white fibres running along the median 

 concave side of the hippocampus major. It is a continuation of the pillars of 

 the fornix. Also called taenia hippocampa and corpus fimbriatum. 



The taenia semilunaris consists of commissural fibres between the corpus 

 striatum and the optic thalamus. 



The cerebrum is thai portion of the brain which lies in front of the cere- 

 bellum ami pons Varolii. It comprises aboul seven-eighths of the weight oi 

 the brain. It is the center of intelligence and thought . 



