ANATOMY OF THE HORSE. 
307 
eighth pair of nerves, and the inferior maxillary neiTe. This fora¬ 
men is bounded in front by the ala of the sphenoid bone, whose 
borders are joined to the temporal and ethmoid bones by the sphe¬ 
noidal suture. Cumno; forw^ards and downwards from the ala is 
the pterygoid process; it aiticulates along its front part with the 
palatine styloid process, w^hich is comparatively slender and de¬ 
scends beyond it. x4tthe root of the pterygoid process is seen the 
pterygoid foramen, forming one continued passage with the infero- 
posterior orbital hole. 
2. The INFERIOR facial region constitutes the remain¬ 
der of the inferior surface: it is bounded, posteriorly, by. the 
sphenoid and ethmoid bones; and, anteriorly, by the incisive teeth. 
Beginning from behind, we perceive,—in the middle, the broad 
part of the vomer, embracing the body of the ethmoid; and its 
superior cornua extending under that of the sphenoid bone, at 
whose points are found the spheno-palatine foramina, vA\\q\\ open 
again under the infero-posterior orbital: anteriorly to this it arti¬ 
culates with the palate bones, both laterally and along their mid¬ 
dle—Laterally, the palatine styloid processes, and the nasal and 
palatine surfaces and borders of the palate bones, by which latter 
is formed the posterior opening of the nose: this aperture in its 
general figure is oval lengthwise, and is equally divided into two 
semilunar halves by the shaft of the vomer,about one-third of whose 
length is seen through the orifice. Farther outward, on the sides 
of this opening, the maxillary tuberosities; immediately above 
them, the maxillary hiatus or entrance to the posterior palatine 
foramen, the infra-orbital canal, and the anterior palatine con¬ 
duit; extending forward from the tuberosities in parallel lines, 
the alveolar processes and cavities for the twelve superior molar 
teeth; from which project inward the palatine processeshctXonfuig 
to the same bone, joined by the palate bones above, and the j)a- 
latine processes of the anterior maxillary bones below: these 
parts, altogether, constitute the bony palate. The anterior third 
of the palate takes the name of interdental space; it is, in fact, a 
longitudinally oval interval, which is incompletely filled by the an¬ 
terior palatine processes. At the junction of the contributing por¬ 
tions of the palate and maxillaiy bones to the palatine arch, oppo¬ 
site and near to the last molar tooth, is the yalato-maxillary fo¬ 
ramen; from which takes its rise the palato-maxillary canal, 
which courses the roots of the alveolar processes, and conducts an 
artery of the same name forwards. Along the middle of the arch 
runs the palatine suture, uniting the palate and superior and an¬ 
terior maxillary bones of one side to their fellows on the other. 
At the external borders of the interdental space, formed by the 
superior and anterior maxillary bones, are the alveolar cavities for 
