38 



ANATOMICAL CONSIDERATIONS. 



to gain a cheap livelihood by a' careless proprietor. These American 

 herds are liable to the claim of some man, almost as wild as the animals 

 themstlves; so also the reported Asian quadrupeds turn out to be the 

 recognized possession of some wandering Tartar. 



However, to leave the consideration of particular parts, and to view 

 the entire body anatomically, the vertebrae or spinal cliain, as forming 

 the base of the skeleton, becomes of primary importance. The back- 

 bone of the horse consists of various pieces, so firmly held together by 

 interlacing ligaments and muscles that students, when desirous of divid- 

 ing the spine of a dead animal, often find it easier to saw the bones 

 asunder than .to separate them with the knife. The neck is composed 

 of seven bones ; the back is formed by eighteen* vertebrae ; i^e loins 

 consist of six pieces, and the sacrum is made up of five distinct parts, 

 although long before adultism all of these last are united by osseous 

 junction. 



SOME OP THE DEBP-SEATED MTJSCIES IMMBDIATELT INVBBTINQ THE SPINE OF THE HORSE. 



1. The hair. 2. The skin. 3. Tlie adipose, or fatty tissue directly under the skin. 4. The burspe mucosae, 

 or synovial sacks placed above each dorsal spine. 5. The yellow, elastic ligament connectinp: the dorsal 

 spines together. 6. The spines of the dorsal vertehrje. 7. The semi-spinalis dorsi muscle. 8. The heads of 

 Uie ribs. 9. The levatores costarum muscle. 10. The ribs. 



The sacrum, therefore, is not reckoned among the true vertebrae, the 

 number of which, however, amounts to thirty-two. Of these many divi- 

 sions, the bones of the neck alone are not subject to deviations. The 

 lumbar may be five or seven, and the dorsal limitation is either one 

 above or one below the usual amount, neither of which varieties are of 

 very rare occurrence. The links of the back-bone differ in form and in 

 function. The dorsal vertebrae seem, at first sight, to possess no lateral 

 processes; whereas in the lumbar region these developments are so ex- 

 tended as to constitute the principal features of the several parts. So 

 also the two first bones of the neck enjoy great motion, and all the links 

 of the neck are very far from stationary. But the parts of the back, on 

 the contrary, are all but fixed; yet, although each is endowed with a 



