Chap, vii.] THE FACE. 113 



be remembered that the mylo-hyoid muscle will be 

 attached to both fragments, and will modify the 

 amount of displacement. Fractures of the ramus 

 ai-e seldom attended with much displacement, muscular 

 tissue being nearly equally attached to both fragments. 



In fractures of the body of the bone, the dental 

 nerve often marvellously escapes injury, a fact that is 

 explained by the supposition that the bones are not 

 usually sufficiently displaced to tear across the nerve. 

 Weeks after the accident, however, the nerve has 

 become so compressed by the developing callus as to 

 have its function destroyed. 



One, or both, condyles have often been broken by 

 falls or blows upon the chin. The gums being firm 

 and adherent, it follows that they are usually torn in 

 fractures of the body of the maxilla, and hence the 

 bulk of the fractures in this part are compound. 



The tcmporo-maxillary articulation is 

 supported by a capsule which varies greatly in thick- 

 ness in different parts. By far the thickest part of 

 the capsule is the external part (the external lateral 

 ligament). The internal part is next in thickness, 

 while the anterior and posterior portions of the capsule 

 are thin, especially the former, which is very thin. 

 Thus, when this joint suppurates, the pus is least 

 likely to escape on the external aspect of the articula- 

 tion, and is most likely to find an exit through the 

 anterior part of the capsule, although this part is to a 

 great extent protected by the attachments of the ex- 

 ternal pterygoid muscle. Immediately behind the con- 

 dyle of the jaw are the bony meatus, and, a little to the 

 inner side, the middle ear. In violent blows upon the 

 front of the jaw, these structures may be damaged, and 

 it is interesting to note that the strongest ligament of 

 the joint (the external lateral) has a direction down- 

 wards and backwards, so as to immediately resist any 

 movement of the condyle towards the slender wall of 



