EEGIONAL ANATOMY 25 



to join with the coronary circle in forming the circumflex 

 artery of the coronet. 



5. Under the Lateral Cartilage two transverse branches, 

 an anterior and a posterior, to form the Coronan/ Circle. 

 The numerous ramifications of these branches anastomose 

 both anteriorly and posteriorly with their corresponding 

 branches of the artery of the opposite side. This circle 

 closely embraces the os coronse. Among the larger branches 

 given ofi' from its anterior portion are two descending, one 

 on each side of the extensor pedis, to assist in the formation 

 of the Circumflex Arteri/ of the Covonarij Cushion. The 

 formation of this last-named artery is completed posteriorly 

 by the before-mentioned branch from the artery of the 

 plantar cushion. 



The Preplantar (Ungual*) Artery.^ — This, the smaller 

 of the two terminal branches of the digital, is situated 

 inside the basilar process of the os pedis. It turns round 

 this to gain the fissure between the basilar and retrossal 

 processes, and becomes lodged in the preplantar fissure. 

 Here it terminates in several divisions which bury them- 

 selves in the os pedis. Before leaving the inner aspect of 

 the pedal wing it supplies a deep branch to the heel and 

 the villous tissue. Gaining the outer aspect of the wing, 

 it distributes a further backward branch, which passes 

 behind the circumflex artery of the pedal bone, and, during 

 its passage in the preplantar fissure, gives off ascending and 

 descending branches, which ramify in the laminal tissue. 



The Plantar (Ungual*) Artery.— This, the larger of 

 the two terminals of the digital, may be looked upon as 

 a continuation of the main vessel. Piunning along the 

 plantar groove, it gains the plantar foramen. Here it 

 enters the interior of the bone (the semilunar sinus) and 

 anastomoses with the corresponding artery of the opposite 

 side. The circle of vessels so formed is called the Plantar 

 Arch or the Semilunar Anastomosis. 



* The epithet ' ungual ' is added by Chauveau to distinguish these 

 arteries from the properly so-called plantar arteries — the terminal 

 divisions of the posterior tibial artery. 



