The tibial nerve is located on the most superficial surface of the popliteal fossa, where it divides from the sciatic nerve in the superior horn of the popliteal fossa and travels down the midline of the popliteal fossa to the inferior border of the popliteal muscle through the tendon arch of the flounder muscle into the posterior region of the calf. Inside the popliteal fossa, it gives off a muscular branch and arthritic cord to the nearby muscles and knee joint. It also gives off the medial peroneal cutaneous nerve with the saphenous vein descending to the back of the calf to join the peroneal nerve. The common peroneal nerve is another terminal branch of the sciatic nerve, which generally originates from the upper corner of the popliteal fossa, travels outward and downward along the medial border of the biceps tendon, crosses the surface of the lateral head of the gastrocnemius muscle, and travels under the head of the fibula to wrap around the fibular neck, where it divides into the superficial peroneal and deep peroneal nerves. The common peroneal nerve is close to the bone surface at the fibular neck, and the surface is not covered by muscle tissue. Therefore, when the fibular neck is fractured or traumatized, it is easy to damage the common peroneal nerve, causing paralysis of the anterior and lateral muscles of the lower leg, resulting in foot drop. The common peroneal nerve in the popliteal fossa sends out the joint branch and cutaneous branch (peroneal nerve traffic branch and peroneal nerve lateral cutaneous nerve)