ANATOMY. 45 



coronary arch is the name given to this arrangement of the arteries, 

 and branches from this arch also supply the coronary band. 



The artery of the frog rises behind the pastern joint at the upper 

 border of the lateral cartilage. It has two branches — a posterior, 

 which runs back and supplies the bull) of the heel, and an anterior, 

 which runs forward and downward through the plantar cushion and 

 supplies the sensitive frog. 



The pre plantar ungual artery is given off inside the wing of the os 

 pedis, passes through the preplantar notch, and runs forward along 

 the preplantar groove on the side of the bone. It helps supply the 

 sensitive lamina: with blood and sends some small branches into the 

 bone to join branches from other arteries. 



The plantar ungual artery is the terminal or last branch of the 

 digital artery (is a continuation of that artery) and enters the os 

 pedis at the plantar foramen. 



The two plantar ungual arteries run forward within the bone and 

 unite to form the circulus arteriosus. From this circle spring ascend- 

 ing and descending branches. The ascending branches, called the 

 anterior laminal arteries, leave the bone through the small openings 

 (foramina ) and supply the sensitive laminae in front. The descending 

 blanches, called the inferior communicating arteries, are about fourteen 

 in number and emerge from the bone by the openings just above its 

 lower edge; they unite to form a large trunk, running around the toe 

 of the os pedis, called the circumflex artery, and this artery gives off 

 ascending and descending branches. The ascending branches pass 

 into the sensitive laminae, and the descending branches, called the 

 solar arteries, numbering about fourteen, run backward through the 

 sensitive sole to form a second circle, called the inferior circumflex 

 artery. 



The veins of the foot are arranged in networks, each network or 

 plexus named from the parts in which it is located. The solar plexus 

 is found running all through the sensitive sole. The laminal plexus 

 runs through and under the sensitive laminae. The coronary plexus 

 surrounds the os corona 1 and upper part of the os pedis, just under 

 the coronary band. 



The veins of the frog are those found in the plantar cushion and 

 sensitive frog; the interosseous veins form a network within the os 

 pedis. The veins of the foot all unite above to form a large trunk, 

 called the digital vein, which runs along the digital artery and carries 

 the blood back toward the heart. The veins of the foot are valveless 

 below the middle of the pastern, an arrangement which allows the 

 blood to flow in either direction when pressure is applied and thus 

 prevents injury. 



