226 
ANATOMY OF THE HORSE. 
transverse septa into six conical alveolar cavities, for lodging 
the incisive teeth. The posterior border is narrow and sloped 
off, and denticulates with the nasal bone. The internal border 
is * broad, quadrilateral, and curved, and denticulates with its 
fellow, forming thereby the superior maxillaiy symphysis, 
through which runs the foramen incisivum, for the transmission 
of the palatine arteries. 
Particularities. —These bones are remarkable for smoothness 
of surface, and closeness and hardness of texture. They are 
united at the symphysis, in the young subject by a fibrous car¬ 
tilage, in the adult by osseous matter; so that, by maceration, 
they are separable in the one instance, inseparable in the other. 
Their alveolar cavities increase in number and size with the aj^e 
and growth of the animal. 
Connexion. —With the superior maxillary and nasal bones, 
and with each other. 
MALAR BONES. (oSSA MALARUM.) 
Situation. —Antero-external part of the orbit. 
Figure. —Irregularly triangular, presenting a broad basis 
forwards. 
Division. —Into three surfaces, three angles, a basiform and 
an apiform extremity. 
Surfaces. — The internal or facial surface is divided into 
two portions by the zygomatic angle or spine : the upper division 
is smooth and nearly flat, with the exception of a depression 
anteriorly, which marks the attachment of the nasalis longus 
labii superioris; the lower part is narrow, and roughened by the 
adherence of the masseter. From this surface, posteriorly, 
arises the zygomatic process, which is very obliquely sloped off, 
and laminated for adaptation to the process of the same name, 
meeting it from the temporal bone, the two together forming the 
zygomatic arch. The internal or maxillary surface is concave, 
to enlarge the capacity of the maxillaiy sinus, to which it con¬ 
tributes. The orbital surface presents a smooth concavity, 
which forms the infero-external part of the orbit, and is separated 
from the facial surface by the orbital angle. 
Angles. — The inferior angle constitutes the principal part 
of the zygomatic spine : it is continuous with the temporal bone 
behind, and in front with the superior maxillaiy. The superior 
angle is lunated, and constitutes the infero-extemal portion of 
the orbital circumference. The posterior angle, or rather bor¬ 
der, is jagged and irregular, and unites with the superior max- 
illaiy bone. 
