Posterior Tibial Artery 489 



Division of its tendon may be performed above the malleolus by 

 a puncture made close behind the posterior border of the tibia, which 

 is exactly halfway between the anterior and posterior aspects of the 

 limb ; or in the hollow between the tip of the malleolus and the tube- 

 rosity of the scaphoid. The latter is the better site for its division, 

 as there the tendon is quite subcutaneous, and out of the way of the 

 posterior tibial artery. But it is equally convenient for the surgeon to 

 divide it deep in the sole, by the same wound by which he cuts every 

 other fibrous structure which hinders his straightening the deformed 

 foot. 



The three muscles of the deep layer of the back of the leg are 

 supplied by the posterior tibial nerve. They all extend the foot ; 

 two of them also flex the toes, whilst the third inverts the foot. 



The posterior tibial artery is one of the trunks coming from the 

 bifurcation of the popliteal, at the lower border of the popliteus, the 

 other being the anterior tibial (p. 492). It divides under cover of the 

 abductor hallucis into the two plantars. 



Its course may be marked by a line which begins about an inch 

 below the lower part of the ham, and ends in the mid-space between 

 the inner malleolus and the os calcis. 



Relation s. At its origin, and for an inch or two down, it rests on 

 the tibialis posticus, then on the flexor longus digitorum, and afterwards, 

 as the muscles narrow into tendons, and the tibia expands, it lies 

 upon the bone, and finally upon the posterior ligament of the ankle- 

 joint. 



Posterior to it are the skin, superficial and deep fascia, the gastro- 

 cnemius and soleus ; the sub-soleus fascia (that is the second layer 

 of deep fascia) ; and the posterior tibial nerve, which crosses the artery 

 two or three inches below its origin. 



70 the injter side are the tibial origin of the soleus, the first few 

 inches of the posterior tibial nerve, and, near the ankle, the tendons of 

 the tibialis posticus and flexor longus digitorum. 



To the outer side is the fibular origin of the soleus, the flexor 

 longus hallucis, and, in the lower three-fourths of its course, the posterior 

 tibial nerve. 



Venae comites, one on either side, join with each other by short 

 branches across the artery, and they ultimately flow into the popliteal 

 vein. 



Xii?ation of the posterior tibial artery in the upper part of its 

 course is performed by bending the knee and extending the foot, so 

 as to slacken the deep fascia and the gastrocnemius, and by resting 

 the limb upon the fibular side. An incision of four inches is made 

 down the leg about a finger's breadth behind the posterior border of 

 the tibia, care being taken not to wound the long saphenous vein. 

 The deep fascia is then incised on a director, and the inner belly of the 

 gastrocnemius, if encountered, is turned outwards. The tibial origin of 



