In a young and fat child, where the inner edge of the tibia cannot be distinctly felt, the best guide to the tendon is a point midway between the front and the back of the ankle. An incision in front of this point might injure the internal saphena vein; behind this point, the posterior tibial artery. 119. =Tendons behind outer ankle.=--Behind the malleolus externus we feel the two peroneal (long and short) tendons. They lie close to the edge of the fibula, the short one nearer to the bone. In dividing these tendons, the knife should be introduced perpendicularly to the surface, and about two inches above the apex of the ankle, so as to be above the synovial sheaths of the tendons. =Tendons in front of ankle.=--Over the front of the ankle, when the muscles are in action, we can see and feel, beginning on the inner side, the tendons of the tibialis anticus, the extensor longus pollicis, the extensor longus digitorum, and the peroneus tertius. They start up like cords when the foot is raised, and are kept in their proper relative position by strong pulleys formed by the anterior annular ligament. Of these pulleys the strongest is that of the extensor communis digitorum. When the ankle is sprained, the pain and swelling arise from a stretching of these pulleys and effusion into their synovial sheaths. A laceration of one of the pulleys and escape of the tendon is extremely rare. The place for the division of the tendon of the tibialis anticus, so as to divide it below its synovial sheath, is about one inch before its insertion into the cuneiform bone. The knife should be introduced on the outer side, so as to avoid the dorsal artery of the foot. Now trace the lines of the arteries, and the landmarks near which they divide. 120. =Popliteal artery.=--About one inch and a quarter below the head of the fibula, or say one inch below the tubercle of the tibia, the popliteal artery divides into the anterior and posterior tibial. The peroneal comes off from the posterior tibial about three inches below the head of the fibula. Consequently we may lay down, as a general rule, that, in amputations one inch below the head of the fibula, only one main artery, the popliteal, is divided. In amputations two inches below the head of the fibula, two main arteries, the anterior and posterior tibial, are divided. In amputations three inches below the head, three main arteries, the two tibials and the peroneal, are divided.