The leg has three main arteries, the anterior tibial, posterior tibial, and peroneal. The popliteal artery divides into the anterior and posterior tibial at the lower border of the popliteus muscle just below the lower edge of the tibial tubercle.

Two and a half cm. (1 in.), or a little more, below the edge of the popliteus muscle the peroneal artery is given off from the posterior tibial.

The Anterior Tibial Artery

Ligation. - The line of the anterior tibial artery may be taken as from just internal to the head of the fibula to a point on the front of the ankle midway between the malleoli. The anterior tibial artery pierces the interosseous membrane, but the anterior tibial nerve winds around the head of the fibula and joins the artery 5 to 7 cm. (2 to 3 in.) or more lower down on its outer side.

In The Upper Third

The artery lies between the tibialis anterior and the extensor longus digitorum muscles. This interspace is better recognized by touch than by sight, though a yellowish line of fat or the presence of some small vessels may indicate its position. The tendency is to make the incision too close to the tibia. This mistake will be avoided if the line of the artery has been marked and the incision made in it. After separating the muscles, the outer edge of the tibia can be felt and on the membrane close to it is the artery with venae comites to each side and the nerve farther out. The needle is passed from without inward, and the veins may be included because they are so firmly bound to the artery and membrane as to be separated only with difficulty (Fig. 561).

Fig. 561.   Ligation of the anterior tibial artery in its upper and lower thirds.

Fig. 561. - Ligation of the anterior tibial artery in its upper and lower thirds.

In The Middle Third

The incision having been made in the line of the artery, the septum between the tibialis anterior and extensor longus digitorum is usually visible as a depressed line. Flex the foot to relax the tendons, and on drawing the extensor digitorum outward the upper part of the extensor longus hallucis is seen, it also is drawn outward and the artery is found lying on the membrane with the nerve in front of it.

In The Lower Third

Here, above the flexure of the ankle, the artery lies on the tibia between the tibialis anterior and the extensor longus hallucis. The nerve is to its outer or inner side or in front of the artery. Flexing the foot allows the tendons to be more readily separated, and movement of the foot and big toe will assist in identifying the muscles.

Posterior Tibial Artery

Ligation. - The line of the posterior tibial artery is from the middle of the popliteal space to the middle of the line joining the internal malleolus and internal tuberosity of the calcaneum; at this latter point it divides into the internal and external plantar arteries (Fig. 562).

In The Middle Of The Leg

The incision should be made 2 cm. (3/4 in.) behind the edge of the tibia, avoiding the long saphenous vein. If the edge of the gastrocnemius comes into view draw it outward, incise the soleus muscle through its entire thickness, dividing the tendinous fibres in the body of the muscle. Separate the edges of the incision and seek for the artery on the obliquely running fibres of the flexor longus digitorum muscle. The nerve is to its outer side. The artery lies directly over the outer edge of the tibia, which can be felt with the finger. It is covered with a thin fascia. The ligature is passed from without inward.

Low Down In The Leg

The incision may be made midway between the inner edge of the tibia and the edge of the tendo calcaneus (Achillis). The artery lies beneath the deep fascia on the flexor longus digitorum muscle with the nerve to the outer side. The muscle has fibres as low down as the malleolus and the artery is to the outer side of its tendon. If the artery is sought behind the ankle then it has the tendons of the tibialis posterior and flexor longus digitorum in front of it. Care should be taken that the main trunk is ligated and not one of its plantar branches in case of a high division.

Fig. 562.   Ligation of the posterior tibial artery.

Fig. 562. - Ligation of the posterior tibial artery.

Peroneal Artery

The peroneal artery is given off from the posterior tibial 2.5 cm. (1 in.) below the lower edge of popliteus muscle. It follows the inner edge of the fibula beneath or in the fibres of origin of the flexor longus hallucis. If it is desired to ligate it, the incision is to be made over the inner edge of the fibula, the edge of the soleus is drawn inward, the fibres of the flexor longus hallucis divided, and the artery found at the junction of the inner edge of the fibula and interosseous membrane. At the lower extremity of the interosseous membrane the artery pierces it to be distributed to the outer anterior portion of the tarsus and ankle.