98 EQUINE ANATOMY. 



PEDAL. 



Divides opposite the second tarsal row into the perforating 

 pedal, which passes between cuboid and scaphoid to anastomose 

 with plantars and collateral artery of the cannon. This passes 

 downward, then backward between external and middle meta- 

 tarsus, then down to top of fetlock, where it divides into the two 

 collateral arteries of the digits, which pass downward to the 

 basilar process of the pedal bone, dividing into the plantar and 

 preplantar ungual. 



Branches. 



To upper bones of digits, joints, tendons, etc. 



To plantar cushion. 



Coronary circle, to structures around os coronae. 



Pre-plantar, enter foramina in os pedis. 



Plantar, passes into plantar fissure, plantar canal and semi- 

 lunar sinus, uniting with opposite to form the semilunar anas- 

 tomosis. 



PULMONARY ARTERY. 



Arises from right ventricle, passes upward and backward divid- 

 ing into two branches, which enter the lungs and ramify in them. 

 At its middle is a fibrous cord, running to the arch of the aorta, 

 the remains of the ductus arteriosus of foetal life. 



The artery carries venous blood to the lungs for oxygenation. 



THE VEINS. 



The veins carry venous blood from the periphery to the heart, 

 except the pulmonary, that carry arterial blood to the left heart. 

 They have three coats, an internal serous, middle muscular and 

 external fibrous. In the lumen of the veins are valves with their 

 concavity toward and their convexity away from the heart. They 

 are absent in the pulmonary and portal veins and vena cava and 

 very large and numerous in the extremities. 



The venae comites are two veins accompanying each small 

 artery; the larger arteries have only one. 



Coronary. 



Small branches and great coronary empty into right auricle 

 after receiving the bronchial veins. 



