268 
ANATOMY OF THE HORSE. 
Form, —Symmetrical, bearing much resemblance to the letter 
V ; the angular or narrow part being presented forwards, the sides 
diverging and opening backwards. 
Division. —Into body, neck, sides, and limbs or branches, to¬ 
gether with their respective external and internal surfaces and 
borders. 
The body is the anterior undivided portion, reaching back so 
far as to include the tusks within their sockets. The neck is the 
contracted part springing from the body; the two together foim- 
ing a solid bond of union between the sides, sustaining them, 
together with the branches, in immovable relative position. In the 
young subject, a longitudinal median suture, named the inferior 
maxillary symphysis, divides the bone at this part into separable 
symmetrical halves; bony union, however, solidifies the two early 
in life, after which they are no longer distinct pieces. The exter¬ 
nal surface of the body is convex and rounded, and in places rough 
and porous, from the attachment of the levator menti and gums. 
A groove across the neck marks the course of the fonner symphy¬ 
sis. At the place where the neck joins the side, near the supe¬ 
rior border, is the anterior maxillaiy foramen, which fomis the 
outlet of a canal running between the laminse of the bone along 
the roots of the molar teeth: it is traversed by the third division 
of the fifth pair of nerves. The internal surface of the body is 
slightly concave, and is rough and porous from the attachments 
of the gums and membrane of the mouth; that of the neck forms 
a channel for the tongue, and receives the insertion of the froenum 
lingTiae. The border projects forward, forming a parabolic curve, 
and presenting, superiorly, conical alveolar cavities for the six 
lower incisive teeth and the two inferior tusks ; posteriorly, on the 
neck, the border rises into a sharp edge, which is rendered less 
prominent in old horses, in consequence, it would appear, of the 
repeated pressure and friction of the bit. 
The sides are the parts comprehended between the neck and 
the branches : they include all the inferior molar teeth. They in¬ 
crease in breadth from before backward, are flattened laterally, 
and present external and internal surfaces, superior and inferior 
borders. The surfaces, though, generally speaking, they may be 
pronounced to be flat, possess a degree of prominence in eai’ly and 
adult life which they lose in age: this may be ascribed in part to 
the teeth, and in part to the comparative porousness or incompact¬ 
ness of structure of the young bone. The external surface is occu¬ 
pied by the depressor labii superioris ; the internal by the muscles 
- of the hyoidean region. The vacuity between the sides takes tlie 
name of inter-maxillaiy space. Of the borders, the superior exhi¬ 
bits twelve quadrangular alveolar cavities for the molar teeth, 
