CIRCULATORY SYSTEM. 187 



into the inferior coronary artery; though other short twigs are sent 

 both upward and downward from it. 



The above two, just described, may be considered as the ante- 

 rior branches of importance : we now proceed to those arising 

 posteriorly : the first we need notice particularly is — 



3. The artery of the frog. It comes off opposite to 

 the pastern-joint, and descends obliquely inward through the sub- 

 stance of the fatty frog, wherein it bifurcates: both divisions 

 take nearly the same direction, one passing down upon the side 

 of the cleft along which it continues, distributing branches in its 

 course to the toe of the frog, and forming communications with 

 the vessels of the sole ; the other ramifies over the heel of the 

 frog, and sends branches outward to the cartilages. 



4. The lateral laminal artery leaves the trunk just 

 as the latter reaches the os pedis, passes through the foramen in 

 the ala, and proceeds within a superficial groove to the front of 

 the foot, distributing branches upward and downward to the 

 lamince, and disappearing through a small foramen in the anterior 

 and lateral part of the coffin, whose substance it enters in order 

 to form a communication with the circulus arteriosus. From 

 this vessel a branch descends upon the side of the bone to join 

 the circumflex artery. 



5. The circulus arteriosus, resulting from the coalition 

 of the main trunks, preserves, to a certain extent around the toe of 

 the coffin, the same curve interiorli/ that is made by the exterior 

 edge of the bone itself, at the distance of about an inch above it. 

 From the circulus arise two principal sets of vessels. 



1. The anterior laminal arteries, numerous, small, 

 short branches springing from the front of the circulus, and 

 making their exit though the various foramina in the front and 

 sides of the coffin, to ramify among the laminae, and anasto- 

 mose with the descending and lateral coffin arteries. 



2. The inferior communicating arteries, '* thirteen, 

 and sometimes fourteen," in number, according to the Professor, 

 arise from the convexity of the circulus arteriosus, and descend 

 through the foramina in front of the coffin, a little above its 

 boundary edge: having made their exit, they continue the same 

 direction to gain the extreme edge, around which they are all 

 received by the 



3. Circumflex artery, which is commonly described as 

 encircling "the toe" of the coffin-bone. Then again, from this 

 vessel spring 



The solar arteries (which may be so named, as well 

 from their radiated arrangement, as from their destination), thir- 

 teen or fourteen in number, though they run from the same 



