638 ANGIQLOGY 



tendons of the Tibialis posterior and Flexor digitorum longus, lying in the same groove, behind 

 the malleolus, the former being the more medial. Next is the posterior tibial artery, with a vein 

 on either side of it; and lateral to the vessels is the tibial nerve; about 1.25 cm. nearer the heel 

 is the tendon of the Flexor hallucis longus. 



Peculiarities in Size. The posterior tibial is not infrequently smaller than usual, or absent, 

 its place being supplied by a large peroneal artery, which either joins the small posterior tibial 

 artery, or continues alone to the sole of the foot. 



Branches. The branches of the posterior tibial artery are : 



Peroneal. Posterior Medial Malleolar. 



Nutrient. Communicating. 



Muscular. Medial Calcaneal. 



The peroneal artery (a. peroncea) is deeply seated on the back of the fibular 

 side of the leg. It arises from the ppsterior tibial, about 2.5 cm. below the lower 

 border of the Popliteus, passes obliquely toward the fibula, and then descends 

 along the medial side of that bone, contained in a fibrous canal between the Tibialis 

 posterior and the Flexor hallucis longus, or in the substance of the latter muscle. 

 It then runs behind the tibiofibular syndesmosis and divides into lateral calcaneal 

 branches which ramify on the lateral and posterior surfaces of the calcaneus. 



It is covered, in the upper part of its course, by the Soleus and deep transverse 

 fascia of the leg; below, by the Flexor hallucis longus. 



Peculiarities in Origin. The peroneal artery may arise 7 or 8 cm. below the Popliteus, or from 

 the posterior tibial high up, or even from the popliteal. 



Its size is more frequently increased than diminished; and then it either reinforces the posterior 

 tibial by its junction with it, or altogether takes the place of the posterior tibial in the lower 

 part of the leg and foot, the latter vessel only existing as a short muscular branch. In those 

 rare cases where the peroneal artery is smaller than usual, a branch from the posterior tibial 

 supplies its place; and a branch from the anterior tibial compensates for the diminished anterior 

 peroneal artery. In one case the peroneal artery was entirely wanting. 



Branches. The branches of the peroneal are: 



Muscular. Perforating. 



Nutrient. Communicating. 



Lateral Calcaneal. 



Muscular Branches. The peroneal artery, in its course, gives off branches to 

 the Soleus, Tibialis posterior, Flexor hallucis longus, and Peronei. 



The Nutrient Artery (a. nutricia fibulas) supplies the fibula, and is directed 

 downward. 



The Perforating Branch (ramus perforans; anterior peroneal artery) pierces the 

 interosseous membrane, about 5 cm. above the lateral malleolus, to reach the front 

 of the leg, where it anastomoses with the anterior lateral malleolar; it then passes 

 down in front of the tibiofibular syndesmosis, gives branches to the tarsus, and 

 anastomoses with the lateral tarsal. The perforating branch is sometimes enlarged, 

 and takes the place of the dorsalis pedis artery. 



The Communicating Branch (ramus communicans) is given oft' from the peroneal 

 about 2.5 cm. from its lower end, and joins the communicating branch of the 

 posterior tibial. 



The Lateral Calcaneal (ramus calcaneus lateralis; external calcaneal) are the ter- 

 minal branches of the peroneal artery; they pass to the lateral side of the heel, 

 and communicate with the lateral malleolar and, on the back of the heel, with the 

 medial calcaneal arteries. 



The nutrient artery (a. nutricia tibiae) of the tibia arises from the posterior 

 tibial, near its origin, and after supplying a few muscular branches enters the 

 nutrient canal of the bone, which it traverses obliquely from above downward. 

 This is the largest nutrient artery of bone in the body. 



