20 HORSESHOEING. 



3. The radius (12) and the ulna (13), to form the elbow 

 joint. These two bones are the basis of the forearm. The 

 ulna, smaller and weaker than the radius, lies behind and 

 projects above it to form the point of the elbow. The lower 

 end of the radius articulates with — 



4. The carpus, or knee (14), which comprises seven small, 

 cubical bones disposed in two horizontal rows, one above the 

 other. The upper row comprises four bones and the lower row 

 three. The lower row rests upon^ — 



5. The large metacarpal or cannon hone, and the two rudi- 

 mentary metacarpal or splint-hones. The lower end of the 

 radius, the upper ends of the metacarpal bones, and the small 

 carpal bones together form the carpal or knee-joint (wrist of 

 man). Of the metacarpals, the middle on© is the largest, 

 longest, strongest, and most important, and is called the large 

 metacarpal, cannon, or shin-hone (15). It articulates at its 

 lower end with the o's suffraginis, or long pastern (17), and with 

 the two small sesamoid bones (20). On each side of the upper 

 part of its posterior surface lie the two long, slender splint- 

 bones (16). The inner splint-bone is sometimes affected with 

 bony thickenings (exostoses) called " splints." 



6. The bones of the phalanges (all bones below the cannon) 

 will be fully described in another place. 



The bones of the hind limbs articulate directly with the 

 pelvis at the hip-joint. They are stronger than the bones of 

 the anterior limbs. We distinguish the following bones in the 

 hind legs : 



1. The highest bone in the hind limb is the femur (21). It 

 is the strongest bone in the entire body. It lies in an oblique 

 direction downward and forward, and at its lower end articu- 

 lates with — 



2. The patella (22), the tibia (23), and the fibula (24), to 

 form the stifle-joint (knee of man). The patella plays over the 

 anterior surface of the lower end of the femur. The fibula is 

 small, and lies against the upper and outer side of the tibia. 

 The latter at its lower end articulates with — 



