114 DISTRIBUTION OF ARTERIES. 



spring three or four vessels of considerable size, running in 

 waving lines upon the inner side of the lower end of the 

 humerus. The upper one- is directed to the ulnar, splitting 

 before it reaches the bone, and sending one branch upward 

 upon the elbow, and another downward to the heads of the 

 flexors ; to which muscles the other branches of this vessel 

 are distributed. 



The spiral artery, the outermost division, turns round the 

 os humeri, passing under the flexor brachii, and sending a 

 recurrent branch to it, to arrive at the front of the radius, 

 where it splits into several branches, of which — 1. Some 

 run into the elbow joint. 2. Others, larger and more numer- 

 ous, penetrate the heads of the extensors. 3. Two long, 

 slender ones descend upon the radius, and give branches, in 

 their course, to the extensor muscles as low as the knee, and 

 there end in ramifications about and into the joint joining 

 with others coming from the radial. 



The radial artery, the principal division humeral, con- 

 tinues its descent along the radius, about the middle of the 

 arm ; the nerve accompanies it first on its outer side, and sub- 

 sequently behind it. A short way above the knee, it splits 

 into the metacarpal arteries. 



The small metacarpal artery descends, within a cellular 

 sheath, along the inner and back part of the knee. It con- 

 tinues its descent along the metacarpal vein, (which runs to 

 its inner side,) till it gets below the knee, and then transmits 

 its divisions down the front of the suspensary ligament ; 

 between it and the canon bone, it sends off branches over 

 the front of the knee, the canon, and suspensary ligament. 



The large metacarpal artery, a continuation of the radial 

 trunk, continues its course down the leg, by the side of the 

 tendo perforatus, passing under the posterior annular liga- 

 ment, approaches the fetlock just above the joint, and then 

 splits into three vessels ; from the middle division three re- 

 current arteries are given out ; the side divisions become the 

 plantar arteries. From the arch below come off two other 

 branches, which descend into the joint. The plantar arte- 



