702 THE VASCULAR SYSTEMS 



the anterior perforating branches from the digital arteries. The outermost 

 interosseous artery gives off a branch which supplies the outer side of the little 

 toe. 



The dorsalis hallucis, or the first dorsal interosseous (a. dor sails Jtalluds), is one 

 of the terminal branches of the dorsalis pedis. It runs forward along the outer 

 border of the first metatarsal bone, and at the cleft between the first and second 

 toes divides into two branches, one of which passes inward, beneath the tendon 

 of the Extensor proprius hallucis, and is distributed to the inner border of the 

 great toe; the outer branch bifurcates, to supply the adjoining sides of the great and 

 second toes. 



The communicating artery (ramus plantaris profundus}, the other terminal 

 branch of the dorsalis pedis, dips down into the sole of the foot, between the two 

 heads of the First dorsal interosseous muscle, and anastomoses with the termina- 

 tion of the external plantar artery, to complete the plantar arch! It here gives 

 off its plantar digital branch, which is named the arteria magna hallucis, or the 

 princeps hallucis. This artery passes forward along the first interosseous space, 

 and, after sending a branch along the inner side of the great toe, bifurcates for 

 the supply of the adjacent sides of the great and second toes. 



The Posterior Tibial Artery (A. Tibialis Posterior) (Fig. 483). 



The posterior tibial is an artery of large size, which extends obliquely down- 

 ward from the lower border of the Popliteus muscle, along the tibial side of the 

 leg, to the fossa between the inner malleolus and the heel, where it divides beneath 

 the origin of the Abductor hallucis, on a level with a line drawn from the point 

 of the internal malleolus to the centre of the convexity of the heel, into the internal 

 and external plantar arteries. At its origin it lies opposite the interval between 

 the tibia and fibula; as it descends, it approaches the inner side of the leg, lying 

 behind the tibia, and, in the lower part of its course, is situated midway between 

 the inner malleolus and the tuberosity of the os calcis. 



Relations. The posterior tibial artery lies successively upon the Tibialis posticus, the 

 Flexor longus digitorum, the tibia, and the back part of the ankle-joint. It is covered by the deep 

 transverse fascia, which separates it above from the Gastrocnemius and Soleus muscles: at its 

 termination it is covered by the Abductor hallucis muscle. In the lower third, where it is more 

 superficial, it is covered only by the integument and fascia, and runs parallel with the inner 

 border of the tendo Achillis. It is accompanied by two veins and by the posterior tibial nerve, 

 which lies at first to the inner side of the artery, but soon crosses it, and is, in the greater part 

 of its course, on its outer side. 



M 



PLAN OF THE RELATIONS OF THE POSTERIOR TIBIAL ARTERY. 



In front. 



Tibialis posticus. 

 Flexor longus digitorum. 

 Tibia. 

 Ankle-joint. 



Inner side. Outer side. 



Posterior tibial nerve, Posterior tibial nerve, 



upper third. lower two-thirds. 



Behind. 



Integument and fascia. 

 Gastrocnemius. 

 Soleus. 



Deep transverse fascia. 

 Posterior tibial nerve. 

 Abductor hallucis. 



