THE FACE. 143 



the nasal processes of the superior maxillary bones. They are 

 oblong and of a dense compact structure, being so applied to 

 each other as to form a strong arch called the bridge of the 

 nose, which is farther sustained by the nasal spine and the 

 continuous oblique serrated surface of the os frontis. 



The ossa nasi are thick and serrated at their upper margins; 

 below, they are thin and irregular. The surfaces by which 

 they unite with each other are broad, having their edges raised 

 where they join the nasal lamella of the ethmoid bone. The 

 edge by which they join the nasal process of the upper maxil- 

 lary bone is concave; the upper part of this edge is overlapped 

 bv the nasal process, but the lower part of it overlaps the na- 

 sal process. 



On the posterior face of the os nasi is to be seen a small 

 longitudinal groove, formed by the internal nasal branch of the 

 ophthalmic nerve, which nerve penetrates the foramen orbitale 

 anterius and the cribriform plate of the ethmoid bone. 



The ossa nasi articulate with each other in front, with the 

 nasal processes of the upper maxillary behind, with the septum 

 narium where they are in contact with one another, and with 

 the os frontis above. 



4. Unguiform Bones, (Ossa Ungues, Os Lacrymaux.) 



The unguiforrn is a very small thin bone, "placed at the in- 

 ternal side of the orbit, between the nasal process of the upper 

 maxillary and the os planum of the ethmoid. Its orbitar sur- 

 face is divided into a face which is in a line with that of the 

 os planum, and into an oblong vertical concavity, continuous 

 with the concavity on the posterior surface of the nasal pro- 

 cess, for lodging the lachrymal sac. Its inferior anterior cor- 

 ner is elongated into the nose, so as to join with a process of 

 the inferior turbinated bone, whereby the ductus ad nasum is 

 rendered a complete bony canal. 



This bone lies on the orbitar side of the most anterior eth- 

 moid cells, and completes them in that direction. 



An important variety in the structure of this part of the or- 

 bit occasionally occurs, in which the whole fossa for lodging 



