You may need to expose a patient's popliteal artery in wounds of his popliteal fossa. This is difficult. Although the popliteal fossa looks easy in diagrams, in reality all its contents are cramped together. Nerves, arteries, and veins all look much the same until you dissect them out carefully. Unless you have previously exsanguinated the patient's leg with an Esmarch bandage, blood will flood up everywhere, and you can easily injure his common peroneal nerve.
The popliteal artery begins as the continuation of the femoral artery, at the opening in adductor magnus. It then runs downwards in the popliteal fossa until it reaches the lower border of the popliteus muscle, where it divides to form the anterior and posterior tibial arteries, and the peroneal artery. The popliteal vein lies medial to the lower end of the popliteal artery and crosses it posteriorly to lie posterolateral to its upper part. The medial popliteal nerve crosses the popliteal artery and vein posteriorly from the lateral side above, to the medial side below. The lateral popliteal nerve lies more superficially in the lateral part of the fossa.
TYING THE POPLITEAL ARTERY Lay the patient prone. If he is having a general anaesthetic he must be given a relaxant and intubated, and his respiration controlled. Exsanguinate his leg with an Esmarch bandage and apply a tourniquet.
Make a 15 cm ''lazy S' incision over the centre of his popliteal fossa, with the distal end on the medial side, so as to avoid his superficially placed lateral popliteal nerve. Carefully cut through his superficial fascia. Find his sural nerve and hold it aside. Now incise the fascial roof of his popliteal fossa vertically, and retract his hamstring muscles and the two heads of gastrocnemius.
CAUTION ! Before you tie his popliteal artery, carefully separate it from the vein and nerves which accompany it.
If necessary, you can carry the incision downwards to expose the lower part of his popliteal artery and the origin of his two tibial arteries. Divide the fibrous arch which crosses these vessels and the fibres of his soleus muscle which arise from it.
The popliteal artery has few collateral branches, so preserve as much of its length as you can by by tying it close to the lesion. Pass an aneurysm needle round it, tie it with zero silk or linen, and don't divide it.