54 OF THE HEAD. 



CHAPTER II. 



Of the skeleton and its different parts, and the individual bones of which they 



are composed. 



The bones of an animal arranged and connected to each other 

 in their natural order, separate from the soft parts, compose a 

 skeleton. 



The skeleton is said to be natural when the bones are 

 connected by their own ligaments, which have been allowed to 

 remain for that purpose. 



It is called artificial when the bones are connected with wire, 

 or any foreign substance. 



The artificial skeleton is best calculated for studying the 

 motions of the different bones, because the dry and hard 

 ligaments of the natural skeleton do not allow the bones to 

 move ; but the bones of young animals do not admit of the 

 preparation necessary for an artificial skeleton, as their epiphyses 

 would separate, and they are therefore formed into natural 

 skeletons. 



The study of the skeleton and its mechanical properties, as a 

 piece of machinery, is absolutely necessary to a perfect under- 

 standing of many motions of the body, and of the action and 

 co-operation of muscles ; but any observations on this subject 

 will be better understood after the individual bones and the 

 muscles have been described. 



The skeleton is divided into the head, the trunk, the superior 

 and the inferior extremities. 



Of the Head. 



The Head comprehends the Cranium, and Face. 



The cranium consists of eight distinct bones, which, when 

 placed in their natural order, form a large spheroidal cavity .for 

 containing the brain, with many foramina or apertures that 

 communicate with it. 



