Chap. 5 



CHAP, V. 



DIVISION OF THE SKELETON, WITH THE BONES 

 OF THE HEAD. 



*The Skeleton briefly defcribed. Bones of the CraniuiH. Bones of the 

 Face of the Nofe of the Palate. The Upper and Under y#<iv.-^- 

 Form and Proportion of the Head.-z-Subjlance omd Structure of the 

 Bones of the Head.- Sutures. 



TH E flteletohj by which is underftood all the 

 bones of the body in their proper fituations, is 

 divided into the head, trunk, and extremities. 



When the bones are put into a natural fituation, 

 fcarcely any one of them will be found to have, a per- 

 pendicular bearing on another ; though the fabric coiii- 

 pofed of them is fo contrived, that in an erecl: pofture 

 a perpendicular line from the common centre of gra- 

 vity falls in the middle of their common bafe. On 

 this accountj we can fupport ourfelves as firmly, as if 

 the ?xis of all the bones had been a ftrait line, per- 

 pendicular to the horizon j and we have much greater 

 quicknefs, eafe, and ftrengthj in feveral of the neceffary 

 motionsj as well as other advantages in the fituation 

 and protection of the vifcera. It is true, indeed, that 

 wherever the bones on which any part of the body is 

 fuftained, decline from a ftrait line, the force of the 

 mufcles required to counteract the gravity is greater 

 than would be otherwife neceflary ; but this is more 

 than compenfated by the advantages above men- 

 tioned. 



The bones of the head are divided into thofe of the 

 cranium and face. The cranium, or that bony cafe 

 which furrounds and prot^fts the bra^, confifts of 



VOL. III. H eight 



