34 



Bones of the Skull. 



Processus condyloideus 



Collum 



Capitnlum 



Incisura mandibulae 



Processus coronoideus 



< Kaniiis mandibulae 



Crista buccinatoria 



Juga alveolaria 



._. Limbus 

 alveolaris 



Pars 

 alveolaris 



Angulus mandibulae 



Basis mandibulae 



Linea obliqua 

 A 



Corpus mandibulae 



Tuberculum 

 mentale 



Protuberautia 

 mentalis 



43. Lower jaw bone, mandibula, right halt; from without. 



The mandibula (lower jaw bone), (0. T. inferior maxillary bone) (see also Figs. 42, 4450, 

 55 58, 65 66) is unpaired and forms the interior anterior part of the facial skull. It consists 

 of the parabolically curved corpus, and two rami, which ascend from the ends of the corpus. 



The corpus mandibulae (body of lower jaw) (see also Figs. 42, 44 50, 55 58, 65 

 and 66) consists originally of two halves united with one another in the median plane, the 

 union taking place in the first or second year of life. The point of union is often indicated 

 by a groove. Each half represents a mass of bone which is higher than it is thick, and curved 

 in front so as to be markedly convex externally. Its inferior margin, basis mandibulae, is 

 somewhat thickened and rounded; close above this, near the median plane, is situated the 

 somewhat roll- shaped, transversely placed protuberantia mentalis (0. T. mental process), which, 

 lateralward, runs out into the tuberculum mentale. Somewhat lateralward and upward from 

 the latter a round foramen mentale (for the a. mentalis ; n. mentalis) is visible ; it is usually 

 situated below the alveolus of the second praemolar, about half-way between the base and 

 the upper margin. Beneath it, or somewhat further back, begins the line a obliqua (0. T. ex- 

 ternal oblique line) extending obliquely upward to the anterior margin of the ramus. The 

 upper part of the body, pars alveolaris , dependent in development upon that of the teeth, 

 is bounded above by a narrow border, the limbus alveolaris. It contains on each side eight, 

 altogether then sixteen, alveoli deutales which are separated from one another by thin septa 

 interalveolaria ; the alveoli are wide at the opening and become narrower in the depth, being- 

 exact impressions of the roots of the teeth which they hold. Oblong projections, jug a alveolaria, 

 usually caused by the three anterior alveoli only, are observable on the outer surface. The 

 medial surface of the corpus presents, close to the median plane, the single or double, short 

 spina mentalis (0. T. genial tubercles) (for the mm. geniohyoid., geniogloss.) and on each side 

 below it, somewhat lateralward, the fossa difjastrica (for the m. digastricus). 



