Figure 13a. Peroneus brevis split and rerouting (Chrisman-Snook procedure) in a 19-year-old woman. (a, b) Anteroposterior (a) and oblique (b) radiographs of the ankle show a fibular tunnel (arrows). (c) Longitudinal US image shows a portion of the split peroneus brevis tendon (solid arrow) entering the anterior end of the fibular tunnel (open arrow). F = fibula. (Left side of image is proximal.) (d) Longitudinal US image shows a segment of the peroneus brevis tendon (solid arrow) between the posterior aspect of the fibular tunnel (open arrow) and the calcaneal periosteal flap (arrowheads). C = calcaneus, CFL = calcaneofibular ligament, PB = spared half of the peroneus brevis tendon, PL = peroneus longus tendon. (Left side of image is superior.) (e) Longitudinal US image shows the peroneus brevis tendon (arrows) exiting the periosteal calcaneal tunnel (arrowheads). C = calcaneus. (Left side of image is posterior.) (f) Transverse US image of the split segment of the peroneus brevis tendon shows a distal tendon anastomosis (arrows).