Entrapment neuropathy of common peroneal nerve by fabella: A case report

Figure 1 Results of the neuromuscular ultrasound. A: The atrophic peroneus longus and peroneus brevis muscles on a short axis scan of the symptomatic side, graded 3/4 on the modified Heckmatt scale; B: The peroneus longus and peroneus brevis muscles of the contralateral asymptomatic side; C: The common peroneal nerve in the popliteal fossa (arrowhead); D: The common peroneal nerve adjacent to the fabella (arrow). The nerve was enlarged when it lied closer to the fabella. PL: Peroneus longus; PB: Peroneus brevis.

Figure 2 Results of the computed tomography scan of both lower extremities. Cross sectional area of the right peroneal muscles: 209.55 mm²; average Hounsfield unit for the right peroneal muscles: -50.16; cross sectional area of the left peroneal muscles: 332.22 mm²; Hounsfield unit for the left peroneal muscles: 34.28.