96 MAXILLA INFERIOR. 



maxillary and palate bone. These edges of the bone are much 

 thicker than its middle, which is as thin as paper ; in conse- 

 quence of which, and of the firm union or connexion this bone 

 has above and below, it can very seldom be separated entire in 

 adults ; but in a child it is much more easily separated entire, 

 and its structure is more distinctly seen. 



Its situation is not always perpendicular, but often inclined 

 and bent to one side, as well as the nasal plate of the ethmoid 

 bone. 



It is united above to the os sphenoides and the nasal plate 

 of the ethmoid bone ; before to the middle cartilage of the 

 nose ; and below, to the ossa palati and ossa maxillaria supe- 

 riora. 



Maxilla Inferior, or Lower Jaw. 



The form and situation of this bone are so generally known, 

 that they do not require description. To acquire an accurate 

 idea of the lower jaw, it is, however, necessary to examine 

 attentively its different parts : viz. the chin, or mental protuber- 

 ance, the sides, the angles, and the processes. 



In subjects where the bones are strongly marked, there 

 is a prominent vertical ridge in the middle and most inferior 

 part of the chin which becomes broad below so as to form a 

 triangle, and on each side of this triangular prominence are 

 transverse ridges ; from these eminences the muscles of the lower 

 lip originate. 



On each side of the jaw, commonly under the second of the 

 bicuspides, or small molar teeth, is the anterior maxillary or 

 mental foramen, through which pass out branches of the 

 inferior maxillary nerve and blood-vessels.^ This foramen, 

 has a direction upward and backward. At a ?mall distance 

 behind these foramina, on each side, is the commencement of a 

 ridge which continues backward until it forms the edge of the 

 anterior or coronoid process. The alveolar processes, which 

 form the upper edge of the jaw, are on the inside of this ridge ; 

 the alveoli or sockets corresponding with the roots of the teeth, 

 in number and form. The lower edge of the jaw, which is 



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