28 ANATOMY OF THE HORSE. 



circular borders, sloped ofF behind, which, posteriorly, lie upon 

 the wings of the sphenoid, laterally, are embraced by the bifid 

 orbital plates of the frontal bone, and, in fine, received into the 

 mortise of the same. Upon their internal surfaces the alae sup- 

 port the anterior lobes of the cerebrum : their opposite surfaces 

 constitute within the orbits the ossa plana. 



Connection — With the sphenoid and frontal, the vomer and 

 superior turbinated bones ; and with the cartilaginous septum 

 of the nose. 



H.— THE FACE. 



The face constitutes the antero-superior, anterior, and inferior 

 parts of the head, making altogether (including the inferior 

 maxilla) about four-fifths of the whole: it is the part to which the 

 head owes its prolongation anteriorly, and principally its lateral 

 breadth. It is bounded, behind, by the cranium ; at the sides, 

 by the zygomatic and orbital arches ; infero-posteriorly, by the 

 ethmoid and sphenoid bones, and the basilar process of the oc- 

 cipital. It is composed of two perfectly distinct and separable 

 parts ; viz. the superior maxilla or syncranium • and the inferior 

 maxilla or diacranium : the latter consists of a single or indivi- 

 sible piece, called the lower jaw ; the former or upper jaw is con- 

 stituted of seventeen pieces, but which are closely and immove- 

 ably united ; viz. the nasal bones, the superior and anterior 

 maxillary, the malar, the lachrymal, the palatine, the superior 

 and inferior turbinated, and the vomer : the teeth are equally 

 distributed between the jaws. First, of the superior maxilla. 



NASAL BONES. (OSSA NASI.) 



Situation. Superior part of the face j where they constitute 

 the roof of the cavity of the nose. 



Figure — Vaulted, thin, elongated ; mostly convex externally, 

 concave internally ; broad posteriorly, tapering and terminating 

 in a sharp point anteriorly : the single bone represents the sec- 

 tion (about one-third) of a hollow cone, split longitudinally ; the 

 two bones together form the outline of a heart as painted on 

 cards. 



Division — Into two surfaces, two borders, a base and an apex. 



Surfaces. The External is not merely smooth ; it is polish- 

 ed. It is not everywhere uniformly convex : indeed, the sides 

 are towards their middle slightly concave ; and the outward side 

 is most depressed. — The Internal Sutface is concave, that it may 

 enlarge the area of the cavity of the nose : the channel it forms 



