NASAL BONES. 45 



fossa, the upper boundary of the middle meatus. The anterior border 

 presents a number of incomplete cells, which are closed by the 

 superior maxillary and lachrymal bones ; and the posterior border is 

 irregularly cellular, to articulate with the sphenoid and palate bones.* 



The lateral masses are composed of cells, which are divided by a 

 thin partition into anterior and posterior ethmoidal cells. The ante- 

 rior, the most numerous, communicate with the frontal sinuses, and 

 open by means of an irregular and incomplete tubular canal, the 

 infundibulum, into the middle meatus. The posterior cells, fewer in 

 number, open into the superior meatus. 



Developement By three centres ; one for each lateral mass, and 

 one for the perpendicular lamella. 



Articulations. With thirteen bones ; two of the cranium, the 

 frontal and sphenoid; the rest of the face, viz. the nasal, superior 

 maxillary, lachrymal, palate, the inferior turbinated, and the vomer. 



No muscles are attached to this bone. 



BONES OF THE FACE. 



The face is composed of fourteen bones ; viz. the 

 Two nasal, Two palate, 



Two superior maxillary, Two inferior turbinated, 



Two lachrymal, Vomer, 



Two malar, Inferior maxillary. 



NASAL BONES. The nasal (fig. 23) are two small quadrangular 

 bones, forming by their union the bridge and base of the nose. 

 Upon the upper surface they are convex, and pierced by a foramen, 

 for a small artery ; on the under surface they are somewhat con- 

 cave, and marked by a groove, which lodges the nasal branch of 

 the ophthalmic nerve. The superior border is narrow and thick, the 

 inferior broad, thin, and irregular. 



Developement. By a single centre for each bone. 



Articulations. With four bones ; frontal, ethmoidal, nasal, and 

 superior maxillary. 



Attachment of Muscles. It has in relation with it the pyramidalis 

 nasi, and compressor nasi ; but neither of these muscles is inserted 

 into it. 



SUPERIOR MAXILLARY BONES. The superior maxillary are the 

 largest bones of the face, with the exception of the lower jaw ; they 

 form, by their union, the whole of the upper jaw, and assist in the 

 construction of the nose, the orbit, the cheek, and the palate. Each 

 bone is divisible into a body and four processes. 



* Mr. Wilson has entirely omitted the description of the pyramids of Wistar, which 

 in their early stage project as thin triangular laminae from the posterior borders of the 

 lateral masses. As they become developed the edges of the laminae fold over so as to 

 form an imperfect triangular pyramid, encroaching upon the body of the sphenoid 

 bone on its under surface, and finally coalescing with it so as to perfect the sphenoidal 

 cells. The remains of these pyramids may be seen on the adult bone, and are called 

 by Wilson the sphenoidal spongy bones. They were first studied by Professor Wistar, 

 and are called after him. G. 



