46 



THE SKELETON OF THE HOESE 



(Facies articularis tuberculi costse) for articulation with the transverse process of 

 the corresponding thoracic vertebra. 



The sternal extremity (Extremitas sternalis) is sUghtly enlarged, and is united 

 with the costal cartilage. 



The first rib is easily distinguished. It is shortest and the shaft widens greatly 

 toward the sternal end. At the lower part of the anterior border there is a smooth 



Tubercle 



Neck 



Head Xeck Tubercle 

 Groove 



Costal groove 



Head 



Anterior border 



Sternal extremity 



Fig. 



22. — Left Eighth Rib of Horse; 

 ERAL View. 



Lat- 



Costo- 

 chondral 

 junction 



Sternal extremity of costal cartilage 



Fig. 23.— Right Eighth Rib and Costal Cartilage of 

 Horse; Medial View. 



impression where the brachial vein curves around it; above this there is commonly 

 a small tubercle (Tuberculum scaleni) which indicates the lower limit of the in- 

 sertion of the scalenus muscle. The costal groove is absent. The head is large and 

 has two facets of unequal extent, which meet at an acute angle in front; the smaller 

 one faces forward and articulates with the last cervical vertebra; the larger one is 

 directed medially and articulates with the first thoracic vertebra. The neck is 

 thick and very short. The tubercle is larger than that of any other rib and has an 



