POSTERIOR TIBIAL. 531 



intermuscular fascia, which separates it above from the Gastrocnemius and 

 Soleus muscles. In the lower third, where it is more superficial, it is covered 

 only bv 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 EELATIONS OF THE POSTERIOR TIBIAL .ARTERY. 



In front. 



Tibialis Posticus. 

 Flexor Lon:us Digitorum. 

 Tibia. 

 Ankle-joint. 



Inner side. I p oste rior ) Outer side. 



Posterior tibial nerve, 1 Tibiai. ) Posterior tibial nerve, 



upper third. V / lower two-thirds. 



Behind. 



Gastrocnemius. 



Soleus. 



Deep fascia and integument. 



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

 lowing order, from within outwards : First, the tendons of the Tibialis Posticus 

 and Flexor Longus Digitorum, lying in the same groove, behind the inner 

 nialleolus, the former being the most internal. External to these is the poste- 

 rior 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 supplied 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 trie 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 wound 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 of 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 should be made through 

 the integument, about two inches and a half in length, midway between the heel and inner ankle, 

 or a little nearer the latter. The subcutaneous cellular membrane having been divided, a strong 

 and dense fascia, the internal annular ligament, is exposed. This ligament 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 round the vessel from the heel towards the ankle, 

 in order to avoid the posterior tibial nerve, care being at the same time taken 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, and its being covered by the Gastrocnemius and 

 Soleus muscles. The patient being placed in the recumbent position, 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, along the inner margin- of the tibia, taking care to avoid the internal saphenous 

 vein. The deep fascia having heen 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 



