The popliteal fossa is a depressed fossa at the back of the knee joint, which can be clearly palpated when we flex the knee normally and is diamond shaped. It is bounded by the tendon of the biceps femoris at the outer upper border and the semitendinosus and semimembranosus muscles at the inner border. Its lower inner and lower outer boundaries are the medial and lateral heads of the gastrocnemius muscle, respectively, and anteriorly the posterior joint capsule of the knee, popliteal oblique ligament, and popliteal fascia. The top of the popliteal fossa is the popliteal fascia, which is a continuation of the broad fascia of the thigh. It can be said that the popliteal fossa is the channel of the blood vessels, nerves and lymph of the human calf, and it is also a necessary route. If any one of these structures is damaged, it will cause great impact and damage to the human calf.