21 



Branches of the A. digitalis lateralis. 



(i) Numerous small branches to the ergot, joints, tendons and tendon 

 sheaths. 



(2) A. phalangis primae. (Artery of the first phalanx). This is a 

 short trunk which arises at a right angle near the middle of the first phalanx 

 and divides almost immediately into an anterior and a smaller posterior 

 branch. The anterior branch divides into an ascending and a descending 

 portion both of which are distributed on the anterior face of the first phalanx. 

 A branch passes between the extensor tendon, which should be cut, and the 

 first phalanx and anastamoses with the corresponding artery of the oppo- 

 site side. The small posterior branch of the A. phalangis primae divides 

 into several branches of which one passes between the infrasesamoidean 

 ligaments and the first phalanx and anastomoses with the opposite artery; 

 the other branches are distributed to the structures on the posterior face 

 of the first, phalanx. 



(3) A. toricae phalangis tertia (artery of the plantar cushion) arises 

 at a right angle from the digitalis, at the proximal border of the lateral 

 cartilage. It extends postero-distally and is distributed to the plantar 

 cushion and to the matrix of the frog. 



(4) A. dorsalis phalangis secundae (dorsal or anterior artery of the 

 second phalanx) . This artery arises at a right angle from the digitalis, 

 near the middle of the second phalanx, and under cover of the lateral 

 cartilage. It extends anteriorily beneath the lateral cartilage and the 

 extensor tendon and anastomes with its fellow of the opposite side. Just 

 as it passes beneath the extensor tendon it gives off a branch to the coronary 

 band or matrix ; it also supplies small branches to the tendon and to the 

 joint capsule. A branch of the volar nerve accompanies the artery. 



(5) A. volaris phalangis secundae (ventral or posterior artery of the 

 second phalanx) is smaller than the preceding opposite to which it arises. 

 It passes above the proximal border of the navicular bone and anastomoses 

 with its fellow of the opposite side. 



(6) A. dorsalis phalangis tertiae (dorsal artery of the third phalanx) arises 

 from the digitalis at the inner or medial side of the wing of the third phalanx. 

 In company with the posterior branch of the N. volaris, it passes through 

 the notch (or foramen) of the wing of this bone and extends anteriorly in 

 the vascular groove on the lateral surface of the bone. It gives off a pos- 

 terior branch to the plantar cushion. 



The branches of the A. digitalis mediahs are the same as those of the 

 A. digitalis laterales. 



