

mi BONK 



second vertebras incline slightly backward; in the third they are more up 

 ri^'ht ; and in the succeeding ones are directed a little forward. In tin- lust 



two they are remarkable for their 

 thickness; in the fifth an oval-shaped 

 articular facet is ohserved on their 

 posterior border: in the sixth, two 

 are present one in front, correspond- 

 ing to the preceding, and one behind, 

 slightly concave, meeting a similar 

 facet on the sacrum. The fourth and 

 fifth vertebra) very often correspond, 

 at their transverse processes, by 

 means of analogous facets. 1 



In tho Ass, and sometimes in the 

 Mule, only five lumbar vertebras are 

 found. According to M. Sanson, this 

 is the natural number in the Arab 

 Horse. - 



4. Sacrum. 



Tho sacrum results, as already 

 stated, from the consolidation of 

 five vertebrte. This single bone 

 articulates, in front, with the last 

 lumbar vertebra; behind, with tin- 

 first coccygeal bone, and on tin- 

 sides with the ossa innominate. It 

 is triangular, flattened above and 

 below, and from before to behind 

 describes a slight curve up- 

 wards. It offers for study a 

 superior and an inferior face, 

 two borders, a base, a sunn nit, 

 and a central canal, tho exten- 

 sion of the spinal canal. 



Faces. The superior face 

 presents, on its middle, tho spi- 

 nous processes of tho sacral 

 vertebrae, which together con- 

 stitute what is called the samil 

 or supersacral spine. These 

 processes ore united at their 

 only, and remain isolated 



UPPER SURFACE OF LUMKAH VERTKI',1! 1 . 



1, Summit of spinous process; 2, 2, Anterior 

 articular processes ; 3, 3, Posterior articu- 

 lnr processes ; 4, 4, Transverse processes. 



Fig. 16. 



LUMBAR VERTEBRA; FRONT VIEW. 

 1, Body; 2, Its articular face ; 3, Superior spinou, 



process; 4, Spinal foramen; 5, Anterior articular .. , 

 processes; 6, 6, Transverse, or costiform pro- * or tho remainder of their ex- 

 cesses; 7, Posterior articular process. tent ; they all incline backwards 



1 We possess the skeleton of a horse which has seven lumbar vertebra', with the 

 normal coinpl'-nic-nt in the other regions. The seventh is no doubt the first sacral. :i> it 

 has all its characters. The fifth sacral vertebra is evidently derived from the coo 

 region. 



* (Thiri statement is scarcely correct. M. Sanson ha established Hie fact that there 

 is in reality no Arab horse; and asserts that tin- >|>rrilic typi- \\ith live lumbar veifdn-.-i-, 

 i* very prolxibly of All lean origin, and that th'-.-e \crtrln;i-, indrpc n<l nlly of their iiuniK<-r. 

 olVi-r individual" characteristic.-, different from those observed in tho vertebra; of the tv|>< 

 which has six.) 



