444 



THE MECHANICAL FUNCTIONS. 



elongated, that the muscles which raise the head 

 have been enlarged and strengthened, and that the 

 spinous processes of the back and neck have been 

 much expanded in order to allow of sufficient sur- 

 face for the attachments of these muscles. The 

 effort requisite to raise, and even support the head 

 is very considerable ; as will appear when we reflect 

 that its weight acts by means of an extremely long 

 lever ; for such is the mechanical office of the 

 elongated neck. But in order to economize the 

 muscular power, an elastic ligament is employed to 

 sustain the weight of the head. This, which is 

 termed the Ugamentum iiucIke, and is represented 

 at N, in Fig. 217, is formed of a great number of 



bands, which connect the hinder part of the cra- 

 nium, at the ridge of the occipital bone, and all the 

 spinous processes of the neck, with those of the 

 back ; the separate slips from each being succes- 

 sively joined together, and composing a ligament of 

 great length and power. It differs in its structure 

 from ordinary ligaments, being highly elastic ; so 

 that it yields to the extension of the neck when the 

 animal lowers its head, and gives considerable as- 

 sistance to the muscles in raising it. In the Deer 



