Bones of the Skull. 29 



Sutura intermaxillaris 



Foramen incisivum 

 f Os incisivum 



Sutura incisiva 



Septa interalveolaria -- ^jjj^jif^ ^K^fcv Sutura palatina mediana 



-- Alveoli dentales 



,- Processus alveolaris 



Processns palatinns - 



Spinae Sulci 

 palatinae palatini ^ 



Limbus alveolaris 



36. The two upper jaw bones, maxillae, united, from below. 



The processus palatinus (see also Figs. 35, 59, 60 and 7375) is a transversely 

 placed plate of bone which goes off medianward from the inferior margin of the facies nasalis 

 and helps to form the bony septum between the nasal and the buccal cavity. At the medial 

 rough margin the two maxillae unite with one another to form the sutura palatina mediana; 

 above the same on each maxilla runs a ridge, crista nasalis, the union of the two ridges 

 serving for the attachment of the vomer and the cartilage of the septum of the nose. The 

 posterior margin lies on the anterior border of the pars horizontalis oss. palatini (sutura 

 palatina transversa). The upper surface is smooth and slightly concave in frontal direction; 

 the inferior surface is rougher and presents near the posterior extremity usually two sulci 

 palatini (for the branches of the a. palatina major) bounded by small ridges, spinae palatinae. 



The processus alveolaris (see also Figs. 34, 35, 55 60 and 6568) is dependent 

 in its development on that of the teeth and extends downward like an arch convex in front 

 and externally, concave behind and internally, from the lower margin of the body. The 

 broader, free, inferior margin, limbus alveolaris, contains eight tooth cavities, alveoli dentales, 

 which are separated from one another by the septa interalveolaria; they have wide mouths 

 and grow narrower in the depth ; they are exact impressions of the corresponding roots of the 

 teeth. The anterior surface of the proc. alveolaris presents oblong projections, jug a alveolaria, 

 corresponding to the anterior five alveoli. The portion of the bone lying most medianward 

 including the most anterior two (incisor-teeth) alveoli represents what is in the foetus a special 

 bone (os incisivum) which fuses early with the rest of the bone; remains of the suture 

 originally present at the site, of union, the sutura incisiva , are usually distinct in the new- 

 born, sometimes also in the adult ; medianward they extend, arch-like, backward to an unpaired 

 opening, foramen incisivum, situated on the inferior surface of the combined proc. palatini; 

 from it proceeds upward the symmetrically forking canalis incisivus (for branches of the a. 

 palatina major, branches of the n. nasopalatinus) and ends on the upper surface of each proc. 

 palatinus by an opening on each side. The two processus alveolares unite in the median plane 

 by the sutura intermaxillaris, the anterior continuation of the sutura palatina mediana ; above 

 this suture there is continued forward on each upper jaw, the crisla nasalis (nasal crest); it 

 is higher in the region of the sutura intermaxillaris than it is behind and ends in front in 

 a projection, the spina nasalis anterior. 



