Bones of the Skull. 35 



Incisura mandibulae Fovea pterygoidea 

 Processus coronoideus \ Capitulum 



v s Processus condyloideus 



Pars _ 

 alveolaris 



Angulus mandibulae 



Sulcus mylohyoideus 

 Fovea submaxillaris 



Linea mylohyoidea 

 Fossa digastrica j > Foyea sublingualis 



Spina mentalis ^ 



Corpus mandibulae 



44. Lower jaw bone, mandibula, right half, from within. 



Above the fossa digastrica on each side begins the linea mylohyoidea (0. T. internal 

 oblique line) (for the mm. mylohyoid., mylopharyng.), which ascends obliquely backward to the 

 medial surface of the ramus. Above the medial part of the latter lies the fovea sublingualis 

 (0. T. sublingual fossa) (for the gland, subling.), usually distinctly marked ; beneath the lateral 

 portion, often less well indicated, the fovea submaxillaris (0. T. submaxiJlary fossa) (for the 

 gland, submax ). Extending forward and downward from the foramen mandibulare (see below), 

 below the lateral part of the linea mylohyoid., is the sulcus mylohyoideus (for the r. mylohyoid. 

 a. alveol. inf. ; n. mylohyoid.). 



The ramus mandibulae (0. T. perpendicular portion) (see also Figs. 42, 43 and 5558) 

 is a broad plate of bone which extends from the posterior end of the body perpendicularly 

 upward or obliquely backward. Its posterior, thicker margin forms with the basis corporis 

 the angulus mandibulae ; its anterior margin begins laterally at the posterior end of the linea 

 obliqua, medianly at the last alveolus, with a small triangular surface on which is often visible 

 the crista buccinatoria (for the m. buccinat.). The lateral surface is smooth, the medial 

 presents about its middle an opening, foramen mandibulare (0. T. inferior dental foramen), 

 which is bounded medianward by a small leaflet of bone , the lingula mandibulae. In the 

 foramen mandibulare begins the canalis mandibulae (0. T. inferior dental canal) (for the a. alveol. 

 inf. ; n. alveol. inf.) which extends, within the spongiosa of the bone, arch -like, downward and 

 forward as far as the median plane; before reaching this, however, it opens also on the ex- 

 ternal surface at the foramen mentale, at the foramen mandibulare the sulcus mylohyoideus 

 (see above) also begins. The upper end of the ramus supports two processes separated from one 

 another by the incisura mandibulae (0. T. sigmoid notch) ; the anterior, processus coronoideus, 

 (for the insertion of the m. temporal.) is bent backward somewhat hook-like, the posterior, 

 processus condyloideus, serves for articulation of the lower jaw with the rest of the skull and 

 supports a roller-like capitulum mandibulae, covered over with cartilage, the long axis of which 

 converges with that of the other side backward toward the anterior circumference of the foramen 

 occipit. magnum. The capitulum sits upon a narrower neck, collum (proc. condyloidei) man- 

 dibulae , and this presents in the medial part of its anterior surface the fovea pterygoidea 

 proc. condyloidei (for the attachment of the m. pterygoid. ext.). 



3* 



