12 EQUINE ANATOMY. 



no head, two deep concave facets in its place; an articular sur- 

 face below for the odontoid process; transverse process very rudi- 

 mentary. The spinous processes are flattened from above, down- 

 ward, are elongated and show two foramina, the anterior trans- 

 mitting a vein, the posterior the vertebral vessels. 



The 2d or axis is very long, has no head, but, in its place, a 

 process convex and smooth below, concave above, articulating 

 with the body of the atlas, called the odontoid (or tooth-like). 

 The spinous process is very elongated antero-posteriorly and 

 divided into two lips. The transverse are little developed. 



The $th has a heart-shaped tubercle on its inferior spine. 



The 6th or tricuspid has a third prolongation on its transverse 

 process. 



The *jth or prominens has a long spine, demi-facets behind for 

 the ist rib, the transverse processes are single, and the vertebral 

 foramen is absent. 



THE DORSAL VERTEBRA. 



The body is short with a projecting head anteriorly, a marked 

 depression posteriorly, and four articular cavities for the heads of 

 the ribs, two in front, two behind. The spinous processes are long, 

 and flattened on the sides. The transverse processes are short, 

 and have a facet for articulation with the tuberosity of a rib. The 

 length of the spines increases to the 5th and then decreases to 

 the 1 8th. The i8th has no facet on its body behind. 



THE LUMBAR VERTEBRA. 



The body is longer and wider than the preceding, the spinous 

 process is shorter and surmounted by a tubercle; the transverse 

 processes are flattened from above, downward, and pass trans- 

 versely outward, the fifth and sixth, and sixth and front of the 

 sacrum articulating by facets. 



THE SACRUM. 



The sacrum consists of five segments, closely fused. It articu- 

 lates with the last lumbar and its transverse process in front, the 

 coccyx behind and the os innominata laterally. 



It is triangular in shape with a base anteriorly articulating with 

 the body, articular and transverse processes of the last lumbar; 

 showing also the vertebral canal, an apex behind articulating 

 with the coccyx, two lateral borders articulating with the innominate 



