THE SKELETON. 



39 



The malar bone is paired. It forms the cheek as well 

 as the lateral and cranial border of the orbit. The arch 

 largely formed by this bone is the zygoma. The process 

 projecting dorsad toward the postorbital process of the 

 frontal bone is the postorbital process of the malar. The 

 masseter muscle originates on the border of the malar. 



The mandible or inferior max- 

 illary is the single bone forming 

 the lower jaw (Figs. 19 and 

 2 1 ) . It is made up of two halves 

 which are united by an immov- 

 able articulation or symphysis at 

 the chin. Each half consists of 

 a horizontal and an ascending 

 ramus. On its alveolar border 

 the horizontal ramus bears three 

 incisor teeth, a canine, two pre- 

 molars and a molar tooth. In 

 the caudal part of the medial sur- 

 face of this ramus is the inferior 

 dental foramen, which transmits 

 the inferior dental nerve and 

 artery traversing the dental canal 

 extending within the bone to 

 the mental foramen on the lat- 

 eral surface near the base of the 

 canine tooth. The space on the 

 dorsal border between the canine 

 and the first premolar tooth is 

 called the diastema. 



The ascending ramus or por- 

 tion of the bone caudad of the 

 inferior tooth is marked by six features: (i) the fossa on 

 the outer or lateral surface which gives insertion to the 



FIG. 20. VENTRAL ASPECT 

 OF LARYNX, HYOID BONES, 

 AND TONGUE. The tongue 

 has been cut transversely 

 near its middle and its 

 muscles fixing it to the 

 hyoid have been removed. 



bh, Basihyal ; ch, ceratohyal ; 

 cr, cricoid cartilage of the 

 larynx ; eh, epihyal ; ep, 

 epiglottis ; lg, cricothyroid 

 ligament ; lyh, thyrohyal ; 

 rg, rings of cartilage in 

 the trachea; tc, thyroid 

 cartilage of the larynx; 

 tm, tympanohyal ; sh, 

 stylohyal. 



