THE VEETEBEAL COLUMN. 25 



from the second to the tenth vertebra, the summit of the spinous process is 

 large and tuberculous; in the last seven it is flattened laterally. Their 

 obliquity is less marked as they proceed backwards ; in the sixteenth and 

 seventeenth vertebra, the spinous process is nearly vertical; it inclines 

 slightly forward in the eighteenth. Those of the tenth, eleventh, and 

 twelfth vertebras are slightly curved like an S. 4. The articular processes, 

 from the first to the tenth vertebra, gradually contract and approach the 

 median line ; in the succeeding vertebrae they, on the contrary, increase, 

 and become concave and wider apart from those of the opposite side. 

 5. The volume of the transverse processes and the size of their diarthrodial 

 facets diminish from before to behind. In the three first vertebras this 

 facet is concave ; in the first nine the articular facet looks outwards and 

 backwards, while the facet on the body looks forwards ; in the last the two 

 facets are directed forwards. These two facets are generally confounded in 

 the seventeenth and eighteenth vertebrae. The first dorsal vertebra much 

 resembles the prominens ; it is distinguished from it, however, by the 

 presence of four diarthrodial facets on its extremities. It also differs from 

 the other vertebras by the shortness of its spinous process, which terminates 

 in a point ; by the size and prominence of its articular processes ; and by the 

 depth of its notches. The last vertebra never has facets on the contour of 

 its posterior cavity. 1 



3. Lumbar Vertebrce. 



GENERAL CHARACTERS. A little longer and wider than the dorsal vertebra), 

 which they resemble in the arrangement of their bodies, these vertebras are 

 characterised : 1, By their short, thin, and wide spinous processes, which 

 are slightly inclined forwards, and are provided at their summits with a 

 scabrous tubercle ; 2, By their largely developed transverse processes, 

 flattened above and below, and directed horizontally outwards; 2 3, By the 

 salient anterior articular processes, hollowed out on each side, and provided 

 externally with a tubercle for insertion ; 4, By their equally prominent 

 posterior articular processes, rounded in the form of a half-hinge. 



SPECIFIC CHARACTERS. The characteristics which may serve to distinguish 

 these vertebras from one another are derived from the body, and the spinous 

 and tran verse processes. 1. From the first to the last there is a progressive 

 diminution in the vertical diameter of the bodies, and an increase in their 

 transverse diameter. The inferior spine on the body becomes shorter and 

 wider from the first to the last vertebra ; in the six vertebras it resembles an 

 elongated triangle whose summit is directed forwards. 2. The spinous 

 processes decrease in width from before to behind, and their anterior 

 border becomes more and more concave ; their summits are thickened and 

 tuberculous in the three first, and thin and sloping forward in the three 

 last. 3. The transverse processes are longer in the middle vertebras 

 than in those placed before and behind. The processes in the first and 



1 In well-formed horses, it is not uncommon to find nineteen dorsal vertebrae, with an 

 equal number of ribs; though in these instances there are most frequently only five 

 lumbar vertebrae. Husson and Goubaux have sometimes met with nineteen, and the 

 normal number in the other regions. Sometimes there are only seventeen dorsal 

 vertebrae. 



2 It has been correctly stated that these processes are the representatives of rudi- 

 mentary ribs which have become united to the vertebras. Therefore it is that they are 

 frequently designated costiform processes. 



