ANATOiMY OF THE HORSE. 29 



is the nasal fossa, the posterior and inferior parts of which are 

 occupied by the superior turbinated bone; the unoccupied part 

 constituting the upper nasal meatus. Posteriorly, between the 

 two bones a sinus is formed, which, though sometimes called 

 the nasal, proves to be nothing more than the anterior chamber 

 of the frontal, the two uniting into one cavity. 



Borders. The Superior is straight; but its edge is turned 

 inward, forming a sort of internal crest, which along with its 

 fellow is embraced by the superior border of the cartilaginous 

 septum of the nose. Along their superior borders the two nasal 

 bones are united — in the young subject by a sort of mortise- 

 connection ; in the adult, by a suture half denticulated and half 

 plain or smooth-edged. — The Inferior Border is waving, and is 

 denticulated and mortised in its articulation with the superior 

 and anterior maxillary bones ; it is united also by denticulation 

 with the lachrymal. 



The Base has its border broadly sloped off and denticulated, 

 and is united with the frontal bone, lying upon its anterior 

 border. 



The Apices of the two bones form together the nasal peak ; a 

 perfectly insulated or unconnected and remarkable projection, 

 which gives support to the nostrils, and has attached to it the 

 dilatator narium anterior. 



Connection — With the frontal, superior and anterior maxillary, 

 and lachrymal bones : the two together maintain, superiorly, in 

 its place, the septum nasi. 



SUPERIOR MAXILLARY BONES. 

 (OSSA MAXILLARIA SUPERIORA.) 



Situation. Supero-lateral parts of the face. 



Figure — Trilateral : thick in the middle ; posterior part, gib- 

 bous ; anterior, thin, tapering and laminous. 



Division — Into three surfaces, two extremities, and three bor- 

 ders. 



27ie External or Facial Surface is partially subdivided into 

 antero-superior and postero-inferior portions by a protuberant 

 ridge named the superior maxillary spine, which forms one 

 continuous line with the zygomatic spine and ends abrubtly op- 

 posite to the third molar tooth : the upper subdivision is much 

 the larger, and affords attachment to the masseter. Rather 

 above the middle of the upper surface opens the infra-orbital 

 foramen, traversed by bloodvessels and nerves bearing the same 

 name. 



The Inferior or Palatine Surface exhibits the concave side of 



