8 4 



ELEMENTAL Y ANA TOMY. 



[LESS. 



in the inner wall of the orbit as what is called the os planum, 

 which is bounded above by the frontal, behind by the sphe- 

 noid, in front by the lachrymal, and below by the maxilla. 

 The inner surface is swollen and irregular. That part of it 

 immediately below the cribriform plate is called the upper 

 spongy bone, or superior turbinate, or turbinal, 1 the part 

 below being termed the middle turbinate. 



Besides the junctions already noted, the ethmoid unites 

 with the sphenoid behind, and with the nasals, vomer, lachry- 

 mals, palatines, and lower turbinate bones (or turbinals). 



8. The MAXILLARY bone supports on each side the teeth 

 of the upper jaw, and forms the bulk of that jaw, and con- 

 tributes to form the cheek, the orbit, the nasal passage, and 

 the palate. The two maxillary bones meet in the middle 

 line below the anterior nares, where each projects as a 

 sharp process the anterior nasal spine. Each sends up a 

 prolongation (the nasal process) to the frontal, bounding the 

 inner side of the orbit anteriorly, and having at its hinder 

 side a lachrymal bone, and on its anterior side a nasal bone. 

 Its hinder surface exhibits a vertical groove. On the opposite 

 or external side the maxillary 

 bone sends a process outwards, 

 which joins the malar, and is 

 called the malar process. Above, 

 the bone exhibits a smooth hori- 

 zontal surface (the orbital plate), 

 which forms the floor of the 

 orbit. In front the bone has a 

 concavity, termed the canine 

 fossa, between which and the 

 lower margin of the orbit is a 

 foramen (called infra-orbital] 

 which transmits the second 

 branch of the fifth nerve. 



From within the alveolar bor- 

 der each maxilla sends inwards 

 &. palatine plate, which is joined 

 by the palate bone posteriorly, 

 but which internally meets its fellow of the opposite side, 

 except where the opening of the anterior palatine canal 

 separates them. 



In the body of the bone is a large cavity called the Cave 

 ot Highmore, or the Antrum Highmori. 



1 So called from being curved like a turbinated shell. 



FIG. 88. FRONT VIEW OF THE 

 RIGHT ORBIT OF MAN. 



<?, greater wing of the sphenoid ; 

 f, frontal bone ; /, lachrymal ; 

 le, qs planum ; ;, malar ; mx, 

 maxillary ; , nasal ; i, optic 

 foramen ; 2, sphenoidal fissure ; 

 3, infra-orbital foramen. 



