Anatomy of the peroneal nerve. The sciatic nerve branches into the tibial and common peroneal nerves superior to the popliteal fossa. The orange bands represent areas of potential injury to the peroneal nerve. The peroneal nerve is most commonly injured during childbirth from prolonged or forceful external compression to the fibular head while grasping and flexing the knee when pushing in the semi-Fowler-lithotomy position. The superficial location of the peroneal nerve as it courses around the fibular head increases the risk of injury or trauma to the peroneal nerve.