38 



ANATOMY FOK NUKSES. 



[CHAP. IV. 



Ceroneid process. 



QmdyU. 



for facM artery. 



-AngU. 



tains the teeth is called the alveolar process, and is excavated 

 into cavities, varying in depth and size according to the size of 

 the teeth they contain. There are eight cavities in each bone : 

 those for the canine teeth are the deepest ; those for the molars 

 are widest and subdivided into minor cavities; those for the 

 incisors are single, but deep and narrow. 



The inferior maxillary, or lower jaw, is the largest and 

 strongest bone of the face, and serves for 

 the reception of the lower teeth. At birth, 

 it consists of two lateral halves, which join 

 and form one bone during the first or sec- 

 ond year. The lower jaw undergoes sev- 

 eral changes in shape during life, owing 

 mainly to the first 

 and second denti- 

 tion, to the loss of 

 teeth in the aged, 

 and the subsequent 

 absorption of that 

 part of the bone 

 which contained 



them. It articulates, by its condyles, with the sockets in the 

 temporal bones. 



The hyoid, os hyoides, or tongue bone, is an isolated, U-shaped 

 bone lying in front of the throat, just 

 above " Adam's apple " ; it supports the 

 tongue, and gives attachment to some of 

 its numerous muscles. 



The irregular bones of the trunk are 

 comprised in the spine, which is formed 

 of a series of bones called vertebrae. 

 The vertebrae are thirty-three in num- 

 ber, and according to the position they 

 occupy are named : 



Cervical 7 



Dorsal . 12 



Lumbar 5 



Sacral 5 



Coccygeal 4 



33 



FIG. 39. INFERIOR MAXILLARY BONE. Outer surface. 



FIG. 40. HYOID BONE. 



