166 



SKELETON OF THE PIG 



The backward slope of the posterior ribs is shght. The first rib is prismatic, has a 

 large sternal end, and a very short cartilage. The width is greatest in the third 

 to the sixth, and the leng-th in the sixth and seventh usually. The tubercle fuses 



with the head on the last five or six. The second 

 3 to the fifth form diarthrodial joints with their car- 



tilages, which are wide and plate-like. 



The fifteenth rib, when present, may be fully developed 

 and its cartilage enter into the formation of the costal arch; 

 but in most cases it is floating, and in some cases it is only 

 about an inch (ca. 2-3 cm.) in length. 



THE STERNUM 



The sternum consists of six segments and re- 

 sembles that of the ox in general form. The first 

 segment (Manubrium) is long, flattened laterally, 



Fig. 175. — Eighth Rib of Pig; L.^t- 



ERAL View. 

 1, Head; 2, neck; 3, tubercle; 4, ante- 

 rior border; 5, sternal extremity. 



1, Head; 



Fig. 176. — Fiest Rib of Pig; Lateral View. 

 neclc; 3, tubercle; 4, anterior border; 5, vascular impression; 

 6, sternal extremity. 



and bears a blunt-pointed cartilage on its anterior end; its posterior end forms a 

 diarthrodial joint with the body. The latter is flattened, wide in its middle, narrow 

 at either end. The widest segments are formed of two lateral parts, which are 

 not completely fused in the adult. The last segment has a long, narrow part which 

 bears the xiphoid cartilage. 



The thorax is long and is more barrel-shaped than in the horse or ox, since the 

 ribs are more strongly curved and differ less in relative length. 



BONES OF THE SKULL 

 Cranium 



The occipital bone has an extensive squamous part, which forms a very broad 

 and prominent nuchal crest. The latter is concave, and is thick and rough above, 

 where it forms the highest part of the skull; laterally it becomes thinner, turns 



