132 EQUINE ANATOMY. 



fifth, then diminish to the last ; their obliquity is less 

 pronounced as it is more posterior, the articular facets 

 are closer to the median line, going towards the tenth, 

 and increase to the last ; the transverse processes, as well 

 as the articular surfaces, diminish from forward back- 

 wards ; the last has no facets on the posterior border. 



Ribs. — Elongated bones, eighteen on each side, leaving 

 between them the intercostal spaces, and being pro- 

 longed downwards by the costal cartilages. 



General characters. — Division : A middle part 

 and two extremities. Middle part : External face has 

 a groove in front and muscular impressions above. 

 Internal face is concave and smooth. The anterior 

 border is concave and sharp, the posterior convex, thick 

 and with vasculo-nervous fissure. The superior ex- 

 tremity has a head formed of two convex facets, 

 separated by a groove and a tuberosity with a flat dia- 

 throdial facet. Tlie inferior extremity has a small 

 irregular cavdty. Development : three nuclei, one for 

 the head, one for the tuberosity, one for the balance 

 of the bone. 



Specific characters. — Division : Eight sternal or 

 true ribs, ten asternal or false ribs ; their length in- 

 creases from the first to tlie ninth, then diminishes to 

 the last, their width increases from the first to the sixth, 

 then diminishes backwards, their curve is shorter and 



