62 OSTEOLOGY, OR ANATOMY OF OSSEOUS SYSTEM 



on itself. Its attached margin articulates in front with the 

 inferior turbinate crest of the superior maxilla, and then ascends 

 abruptly as the lacrymal process to complete the lacrymal 

 canal. Behind this, and nearer the back than the front, the 

 bone is folded down as the maxillary process, looking over the 

 aperture of the antrum, and forming part of its inner wall; 

 on the upper border of this process is the ethmoidal process, 

 which articulates with the uncinate of the ethmoid. Posteriorly, 

 the bone is attached to the inferior turbinate crest of the palate; 

 the posterior extremity is elongated and pointed, the anterior 

 flat and broad. 



The bone articulates with the superior maxilla, lacrymal, 

 ethmoid, and palate. No muscle is attached to it. The negro 

 may have four turbinate bones. 



The Inferior Maxillary Bone (Mandible) 



The lower jaw, or mandible, is the strongest bone of the face, 

 and articulates with the glenoid fossae of the temporals. It 

 consists of a curved horizontal portion or body and two ascend- 

 ing branches or rami. The body shows in the median line in 

 front a faint vertical ridge, the symphysis of two originally 

 distinct pieces; this expands below into the mental protuberance, 

 which presents a prominence on each side called the mental 

 tubercle. The superior or alveolar border is hollowed out into 

 sockets for teeth. The inferior border, or base, is thick and 

 rounded, and projects beyond the superior. Below the incisor 

 teeth is the incisor fossa; more externally is the mental foramen 

 midway between the upper and lower borders, under the 

 interval between the two bicuspids; it is the anterior opening 

 of the dental canal. Below the foramen the external oblique 

 line runs up and back from the mental tubercle to the anterior 

 margin of the ramus behind the teeth. The deep surface of 

 the body presents inferiorly near the symphysis an oval fossa 

 for the attachment of the digastric muscle; above it are the 

 mental spines, the lower being a median ridge . for the genio- 

 hyoid muscles, and the upper a pair of tubercles for the genio- 

 hyoglossi; there may be four tubercles (: :) or two (") or a 

 vertical ridge (|) or one prominence ('). Above them a small 

 foramen penetrates the bone, and above this a narrow median 

 groove marks the symphysis. Below the mental spines, and 



