374 



THE ANATOMY OF THE HORSE 



Each rib is divisible into a body and two extremities. The body has 

 two flat surfaces and two borders ; the latter of which are concave and thin, 

 anteriorly convex, and rounded posteriorly. The head or superior extremity 

 varies in the true and false ribs, as will be better seen by reference to the 



Fig. 21.— a True and False Rib. 



A. Profile view of a >eft true or sternal rib. 



2. Tubi^rclp for altachment to transverse process 



of vertebra. 



3. Head, true. 



4. Body. 



5. Junction of rib and its corresponding sternal 



cartilage. 

 0. Sternal cartilago^ 



B. Profile view of left false or asternal rib (eigh- 



teenth). 



2. Tubercle fused in one witli the head. 



3. Head. 



4. Body. 



5. Junction of false rib and asternal cartilage. 



G. Asternal cartilage. 



C. View of the upper extremity of sternal rib inverted 



to show tlie mode by wiiich tlie articulating 

 surfaces on the upper part of tlie rib corre- 

 spond to the nine anterior dorsal vertebrse. 



1. Body. 



2. Tubercle, separate. 



3. 4. Head (true), showing the two surfaces of 



articulation, and the notch in which tlie 

 round ligament is attached. 



D. View of the last asternal rib, also inverted to show 



the fusion of tubercle and head together. 



1. Body. 



2, 3. Tubercle fused with head. 



engraving (Fig. 21), where one of each kind is delineated. The cartilages 

 are all attached to the ribs by firm union of their fibres to a deejD pit in the 

 extremity of each rib. They serve the double purpose of giving elasticity 

 to the thorax in the act of respiration and of enabling it to bear severe 

 shocks without fracture. 



Among the several ribs, the first is the thickest and shortest, and is 

 irregularly arched ; the second is very slightly curved : from this point they 



