84 



Anatomy oi^* the Rabbit. 



shorter folds decreasing in length from above downward. In the natural 

 condition the turbinated bones bear a considerable portion of the nasal 

 epithelium, the surface of which is greatly increased by the folding of 

 the underlying bone. That covering the ethmoturbinal contains the 

 olfactory sense organs, while that covering the maxilloturbinal is non- 

 sensory and possesses the mechanical function of freeing the air of the 

 respiratory tracts from foreign materials, as well as of warming it slightly in 

 its passage. On this account the respective structures are conveniently 

 distinguished as sensory (olfactory) turbinals and respiratory turbinals. 

 The mandible (mandibula) is composed of two portions, united 

 anteriorly by the symphysis mandibulae. Each half comprises a hori- 

 zontal portion, forming in conjunction wdth that of the opposite side 

 the body of the mandible (corpus mandibulae), and a posterior, vertical 

 portion, the ramus mandibulae, the latter serving for the insertion of 

 the muscles of mastication and for artticulation with the skull. The 



Fig. 34. Lateral surface of the left ramus of the mandible: a.m., 

 angle; cm., body of mandible; cp.m., articular portion (head) 

 of mandible; d.i., d.m., and d.pin., incisor, molar and premolar 

 teeth; f.m., mental foramen; i.m.a. and i.m.p., anterior and 

 posterior mandibular incisures; p.c, coronoid process; p.cd., 

 condyloid process; t.m. and t.pt., masseteric and pterygoid 

 tuberosities. 



body of the mandible bears on its dorsal margin the alveoli of the lower 

 teeth. The mandibular ramus forms a broad plate, the lateral surface 

 of which is occupied in the natural condition by the masseter muscle, 

 while the medial surface forms an area of insertion for the external and 

 internal pterygoids. The surface of the ramus is greatly increased 

 in its posteroventral portion through the expansion of the bone to 

 form the angle (angulus mandibulae), or angular apophysis. The elon- 

 gated articular surface is borne at the end of a vertical, or slightly oblique 

 condyloid process (processus condyloideus). The nerve and vessels of 

 the mandible enter at the mandibular foramen (foramen mandibulare), 

 the latter being situated on the medial surface of the bone immediately 

 behind the last cheek-tooth. 



