450 ARTERIES. 



of the external plantar artery, to complete the plantar arch. It here gives off 

 two digital branches ; one runs along the inner side of the great toe, on its plantar 

 surface, the other passes forwards along the first metatarsal space, and bifurcates 

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



i 



POSTERIOR TIBIAL ARTERY. 



The Posterior Tibial is an artery of large size, which extends obliquely down- 

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

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

 the origin of the Abductor pollicis, 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. It lies successively upon the Tibialis posticus, the Flexor longus 

 digitorum, and, below, upon the tibia and back part of the ankle-joint. It is 

 covered by the intermuscular fascia, which separates it above from the Gastroc- 

 nemius and Soleus muscles. 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. 



PLAN OF THE RELATIONS OF THE POSTERIOR TIBIAL ARTERY. 



In front. 

 Tibialis posticus. 

 Flexor longus digiterum. 

 Tibia. 

 Ankle-joint. 



Inner side. / \ Outer side. 



Posterior tibial nerve, [ Posterior j Posterior tibial nerve, 



upper third. I Tibial. I lower two-thirds. 



Behind. 

 Gastrocnemius. 

 Soleus. 

 Deep fascia and integument. 



Behind the Inner Ankle, the tendons and bloodvessels are arranged in the 

 following order, from within outwards : First, the tendons of the Tibialis posticus 

 and Flexor longus digitorum, lying in the same groove, behind the inner mal* 

 leolus, the former being the most internal. External to these is the posterior 

 tibial artery, having a vein on either side ; and, still more externally, the posterior 

 tibial nerve. About half an inch nearer the heel is the tendon of the Flexor 

 longus pollicis. 



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

 its place being compensated for by a large peroneal artery, which passes inwards at the lower end 

 of the tibia, and either joins the small tibial artery, or continues alone to the sole of the foot. 



Surgical Anatomy. The application of a ligature to the posterior tibial may be required in 

 cases of wound of the sole of the foot, attended with great hemorrhage, when the vessel should 

 be tied at the inner ankle. In cases of wound of the posterior tibial, it will be necessary to enlarge 

 the opening so as to expose the vessel at the wounded point (excepting where the vessel is injured 

 by a punctured wound from the front of the leg). In cases of aneurism from injury of the artery 



