The common fibular nerve originates from the sciatic nerve in the posterior compartment of the thigh or in the popliteal fossa (Fig. 6.92A), and follows the medial margin of the biceps femoris tendon over the lateral head of the gastrocnemius muscle and toward the fibula. Here it gives origin to two cutaneous branches, which descend in the leg: the sural communicating nerve, which joins the sural branch of the tibial nerve and contributes to innervation of skin over the lower posterolateral side of the leg; and the lateral sural cutaneous nerve, which innervates skin over the upper lateral leg.