PEROXEAL ARTERY. 



445 



scending beyond the outer malleolus, it terminates in branches on the outer 

 surface and back of the os calcis. 



Fig. 304. DEEP POSTERIOR VIEW OF THE ARTERIES OP Fig. 304. 



TIIE LEQ (from Tiedeinann). 



a, insertion of the adductor magnus muscle ; b, origin 

 of the inner head of the gastrocnemius ; c, outer head 

 and plantaris ; d, tendon of the semimembranosus 

 muscle; e, popliteus; /, upper part of the soleus divided 

 below its origin from the head of the fibula ; g, peronens 

 longus; h, flexor longus pollicis; i, flexor communis 

 digitorum ; 1, upper part of the popliteal artery ; 2, 

 origin of the superior articular branches ; 3, origin of 

 the inferior articular branches ; the middle or azygos 

 branch is seen between these numbers ; 4, division of 

 the popliteal artery into anterior and posterior tibial 

 arteries ; 5, 5', posterior tibial ; 6, peroneal artery ; 6', 

 its continuation as posterior peroneal ; between 5', and 

 6', the communicating branch ; 7, calcaneal branches ; 8, 

 external branches of the metatarsal of the dorsalis pedis 

 artery. 



The peroneal artery gives off the following 

 branches. 



(a) Muscular branches from the upper part of the 

 peroneal artery pass to the soleus, the tibialis posticus, 

 the flexor longus pollicis, and the peronei muscles. 



(b) A nutrient artery enters the fibula. 



(c) The anterior peroneal artery arises about two 

 inches above the outer malleolus, and, immediately 

 piercing the interosseous membrane, descends along 

 the front of the fibula, covered by the peroneus tertius 

 muscle, and, dividing into branches, reaches the outer 

 ankle, and anastomoses with the external malleolar 

 branch of the anterior tibial artery. It supplies vessels 

 to the ankle-joint, and ramifies on the front and outer 

 side of the tarsus, inosculating more or less freely with 

 the tarsal arteries. 



(d) The terminal branches anastomose with the 

 external malleolar and with the tarsal arteries on the 

 outer side of the foot ; and behind the os calcis with 

 ramifications of the posterior tibial artery. 



(e) The communicating branch, lying close behind 

 the tibia, about two inches from its lower end, is a 

 transverse branch situated close to the bones, which 

 connects the peroneal with the posterior tibial artery. 



PECULIARITIES. The posterior tibial artery, as well 

 as the anterior tibial, is lengthened in those instances 

 in which the popliteal artery divides higher up than 

 usual. Not unfrequently the posterior tibial artery is 

 diminished in size, and is subsequently reinforced 

 either by a transverse branch from the peroneal in the 

 lower part of the leg, or, in rare instances, by two trans- 

 verse vessels, one crossing close to the bone, and one 

 over the deep muscles. In other instances the posterior 

 tibial may exist only as a short muscular trunk in the 

 upper part of the leg, while an enlarged peroneal 

 artery takes its place from above the ankle downwards into the foot. 



The peroneal artery has been found to arise lower down than usual, about three 



