Dr. Foville on the Anatomy of the Brain. 29 



pairs of eminences which I have just pointed out;it extends 

 also to the form of the skull in general, which, in fact, it con- 

 tributes to determine. 



The different transverse sections, which I have supposed to 

 be made on a level with the centre of all these pairs of emi- 

 nences on the median zone of the cranial vault, divide this me- 

 dian zone into four regions, always perceptible during life, and 

 each of them presenting an angular curve on the transverse 

 line which separates it from the neighbouring regions. All 

 of them display too an agreement in form and proportions 

 with the corresponding region of the envelope of the ventricles, 

 which seems to me incontestable. 



The first region, comprised between the frontal eminences 

 and the inferior boundary of the forehead, answers exclusively 

 to the convolutions developed in front of and beneath the cor- 

 pus callosum, and presents but a small projection from above 

 downwards, like the corresponding part of the ventricles. The 

 lower projection on this part of the forehead does not always 

 indicate a considerable development of the corresponding part 

 of the brain. It may, in fact, be simply owing to the great 

 size of the frontal eminences, and in this case the fact may 

 be ascertained by percussion. 



The second region, included between the frontal and pa- 

 rietal eminences, always forms the largest division of the 

 median zone of the cranial vault ; it is arched like the cor- 

 pus callosum itself, and corresponds to the convolutions above 

 this body. Its size, compared with that of the other regions 

 of the bony arch, bears the same proportion to theirs, that the 

 extent of the superior part of the corpus callosum does to 

 the other fibrous parts enveloping the serous cavities of the 

 brain. 



A considerable eminence is very often seen on the median 

 line towards the centre of this region, in the upper part of 

 the os frontis. This also appears to me, like all the other 

 projections on the median line, to be owing to a thickening of 

 the bones. 



The third region, intermediate between the transverse sec- 

 tion of the parietal eminences and the superior occipital pro- 

 tuberances, is scarcely ever convex longitudinally. It is 

 mostly straight or concave in this direction. Frequently even 

 it presents on the median line a well-marked fossa. The 

 complete separation for the two hemispheres at this part, the 

 absence of the corpus callosum, lifted up as in the others by 

 the fluid of the ventricles, and the superior concavity observed 

 in passing from those parts of the ventricles covered by the 

 corpus callosum, to those formed by a distinct fibrous cone 



