Figure 13a. Common peroneal nerve at the fibular neck. (a) Drawing of the anterolateral aspect of the leg shows the course of the common peroneal nerve (dark gray region) and its superficial and deep branches. The light gray region represents the insertion of the peroneus longus muscle. (b, c) Transverse 5-12-MHz US scans show the common peroneal nerve (arrow) before (b) and after (c) winding around the fibular neck. Note the close relationship of the nerve to the osseous surface of the fibula (F).