ANATOMY OF THE HORSE. 
69 
it,) is defective in the essential vertebral properties ; being sim¬ 
ply an irregular ring with broad projecting sides. It has no 
body 5 the place being in part supplied, in the articulated spine, 
by the odontoid process of the second vertebra, for the recep¬ 
tion of which, the infero-posterior part of the ring is made 
smooth and articulatory; this somewhat reduces the dimensions 
of the vertebral hole, though it remains even then the most ca¬ 
pacious of any, and measures more from side to side than con¬ 
trariwise : its inferior surface is deeply impressed by the odon¬ 
toid ligaments. It has no superior spinous process, but there 
is a prominence in the situation of it; and the inferior spine is 
shorter, thicker, and more obtuse than the others. The trans¬ 
verse processes are broad undivided lateral plates, sloping 
downwards, perforated by three pairs of foramina :—one posteri¬ 
orly to their middles, through which run the vertebral arteries ; 
two through their anterior parts, one of which is directed out¬ 
wards and downwards, the other runs inward and opens into 
the vertebral canal: the latter give exit to the sub-occipital 
nerves. The anterior articular processes are represented by four 
horizontal projections, with simicircular borders, whose internal 
surfaces are smooth, placed opposite each other, and together 
form two lateral concavities for the reception of the condyles 
of the occipital bone. The posterior articular processes are 
formed into broad, triangular, convex, smooth surfaces, looking 
backwards, with an inclination inwards. 
The Second Vertebra, ox axis, also denominated the den- 
tata (from a peculiar projection anteriorly, which in the human 
subject is resembled to a tooth) is the largest of the cervical class, 
exceeding the others however more in length than in breadth. 
The body is elongated, and (in place of a hemi-spherical termi¬ 
nation) anteriorly, presents the remarkable process named the 
odontoid, which is smooth and convex below, where it articu¬ 
lates with the infero-posterior part of the ring of the atlas; ex¬ 
cavated and impressed above by the odontoid ligaments. The 
spinous process is very broad, and forms an elevated crest, 
bifid posteriorly. In front of the body are two oval foramina, * 
corresponding to the holes of conjugation. The transverse pro¬ 
cesses are slender, and have only posterior extremities; the 
holes through them are also small. The anterior articular pro¬ 
cess are represented by two broad ovoid smooth surfaces ; unit¬ 
ed with the sides of the odontoid projection ; and sloped off 
backwards, both above and below, to admit of free motion be¬ 
tween them and the posterior articular surfaces of the atlas. 
The Third, Fourth, and Fifth possess the genuine cha- 
