THE POSTERIOR TIBIAL ARTERY 703 



Behind the inner malleolus the tendons and bloodvessels are arranged, under cover of the 

 internal annular ligament, in the following order, from within outward: First, the tendons of 

 the Tibialis posticus and Flexor longus digitorum, lying in the same groove, behind the inner 

 malleolus, 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 hallucis. 



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

 its place being supplied by a large peroneal artery which passes inward at the lower end of the 

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



Surface Marking. The course of the posterior tibial artery is indicated by a line drawn from 

 a point one inch below the centre of the popliteal space to midway between the tip of the internal 

 malleolus and the centre of the convexity of the heel. 



Applied Anatomy. The application of a lif/attire 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 wound of the artery 

 low down, the vessel should be tied in the middle of the leg. But in aneurism ef the posterior 

 tibial high up it would be better to tie the femoral artery. 



To tie the posterior tibial artery at the ankle, a semilunar incision, convex backward, should 

 be made through the integument, about two inches and a half in length, midway between the 

 heel and the inner ankle or a little nearer the latter. The subcutaneous cellular tissue having 

 been divided, a strong and dense fascia, the internal annular ligament, is exposed. This liga- 

 ment is continuous above with the deep fascia of the leg, covers the vessels and nerves, and is 

 intimately adherent to the sheaths of the tendons. This having been cautiously divided upon a 

 director, the sheath of the vessels is exposed, and, being opened, the artery is seen with one of 

 the venae comites on each side. The aneurism needle should be passed around the vessel from 

 the heel toward the ankle, in order to avoid the posterior tibial nerve, care being taken at the 

 same time not to include the venae comites. 



The vessel may also be tied in the lower third of the leg by making an incision, about three 

 inches in length, parallel with the inner margin of the tendo Achillis. The internal saphenous 

 vein being carefully avoided, the two layers of fascia must be divided upon a director, when the 

 artery is exposed along the outer margin of the Flexor longus digitorum, with one of its venae 

 comites on either side and the nerve lying external to it. 



To tie the posterior tibial in the middle of the leg is a very difficult operation, on account of 

 the great depth of the vessel from the surface. The patient being placed in the recumbent posi- 

 tion, the injured limb should rest on its outer side, the knee being partially bent and the foot 

 extended, so as to relax the muscles of the calf. An incision about four inches in length should 

 then be made through the integument a finger's breadth behind the inner margin of the tibia, 

 taking care to avoid the internal saphenous vein. The deep fascia having been divided, the 

 margin of the Gastrocnemius is exposed, and must be drawn aside, and the tibial attachment of 

 the Soleus divided, a director being previously passed beneath it. The arterv may now be 

 felt pulsating beneath the deep fascia about an inch from the margin of the tibia. The fascia 

 having been divided, and the limb placed in such a position as to relax the muscles of the calf 

 as much as jxxssible, the veins should be separated from the arterv, and the aneurism needle 

 passed around the vessel from without inward, so as to avoid wounding the posterior tibial nerve. 



Branches. The branches of the posterior tibial artery are: 



Peroneal. Cutaneous. 



Nutrient. Communicating. 



Muscular. Internal calcaneal. 



Malleolar cutaneous. 



The peroneal artery (a. peronaea} (Fig. 483) lies, deeply seated, along the back 

 part of the fibular side of the leg. It arises from the posterior tibial about an inch 

 below the lower border of the Popliteus muscle, passes obliquely outward to the 

 fibula, and then descends along the inner border of that bone, contained in a 

 fibrous canal between the Tibialis posticus and the Flexor longus hallucis, or in 

 the substance of the latter muscle to the lower third of the leg, where it gives off 

 the anterior peroneal. It then passes across the articulation between the tibia and 

 fibula to the outer side of the os calcis, where it gives off its terminal branches, the 

 external calcaneal. 



