396 NAVIX ON THE HORSE. 



and passes up, forming the metacarpal veins, which pass up the 

 leg, one, on each side, until they reach the back part of the 

 knee, when they spread out into several branches, which again 

 come together above the knee, forming two branches, called 

 the radial veins, or veins of the arm. The principal one 

 passes up the inside of the arm to the elbow, where it, having 

 received the ulna veins, and a few other branches, unites with 

 the smaller radial vein and forms the humeral vein, or vein of 

 the upper arm, which accompanies the artery of this part 

 through the deep-seated muscles to the inner and back" part of 

 the humerus, up to where this bone joins with the shoulder. 

 At this place the humeral vein becomes the axillary vein, or 

 vein of the armpit, which receives several other branches of 

 considerable size from the muscles of the chest and shoulder, 

 and finally terminates within the chest in the anterior vena cava. 

 There are three other branches which emjDty into the vena 

 cava. They come from the muscles of the chest and spine. 



The anterior vena cava is a short, large trunk, within the fore- 

 part of the chest. It receives, as we have seen, the jugular 

 veins, the axillary veins from each fore-limb, a large vein on 

 each side from the chest, also from the neck, and two other 

 pairs from the region of the withers, and another pair from the 

 muscles of the ribs. The anterior vena cava emj^ties into the 

 right auricle; so, also, does the coronary vein, which comes 

 from the body of the heart itself. 



Branches of the Posterior Vena Cava. — The innumerable veins 

 within the hind-foot, just as in the fore-foot, pass up to the 

 pasterns, and, by their union, form the plantar veins, external 

 and internal. These unite and form the principal vein before 

 the hough, the large metatarsal, which passes behind the can- 

 non, and by the side of the back tendons, and forward over the 

 inside of the hough. The continuations of its branches above 

 the hough unite and form the anterior tibial veins, which receive 

 one other large branch, and i:)ass up between the tibia and 

 fibula to the back of the head of the femur. 



