Murlimanju BV, D'Souza PS, Prabhu LV, et al: Peroneus quartus, an accessory muscle in human: case report and its clinical importance. Clin Ter 163: 307, 2012.
Trono M, Tueche S, Quintart C, et al: Peroneus quartus muscle: a case report and review of the literature. Foot Ankle Int 20: 659, 1999.
Sobel M, Levy ME, Bohne WH: Congenital variations of the peroneus quartus muscle: an anatomic study. Foot Ankle 11: 81, 1990.
White AA III, Johnson D, Griswold DM: Chronic ankle pain associated with the peroneus accessorius. Clin Orthop Relat Res 103: 53, 1974.
Hecker P: Study on the peroneus of the tarsus. Anat Rec 26: 79, 1923.
Kassim MM, Rosenfeld P: Tendoscopic debridement of peroneus quartus muscle for chronic lateral ankle pain: a case report. Foot Ankle Int 33: 1024, 2012.
Zammit J, Singh D: The peroneus quartus muscle: anatomy and clinical relevance. J Bone Joint Surg Br 85: 1134, 2003.
Cheung YY, Rosenberg ZS, Ramsinghani R, et al: Peroneus quartus muscle: MR imaging features. Radiology 202: 745, 1997.
Saupe N, Mengiardi B, Pfirrmann CW, et al: Anatomic variants associated with peroneal tendon disorders: MR imaging findings in volunteers with asymptomatic ankles. Radiology 242: 509, 2007.
Zanetti M: Founder's lecture of the ISS 2006: borderlands of normal and early pathological findings in MRI of the foot and ankle. Skeletal Radiol 37: 875, 2008.
Athavale SA, Gupta V, Kotgirwar S, et al: The peroneus quartus muscle: clinical correlation with evolutionary importance. Anat Sci Int 87: 106, 2012.
Kim DH, Berkowitz MJ: Congenital variation of the peroneus longus and brevis muscle-tendon units in association with peroneus quartus: a case report. Foot Ankle Int 27: 847, 2006.
Yong CK: Peroneus quartus and peroneal tendoscopy. Med J Malaysia 61 (suppl B): 45, 2006.
Cerrato RA, Myerson MS: Peroneal tendon tears, surgical management and its complications. Foot Ankle Clin 14: 299, 2009.
Sobel M, Bohne WH, Markisz JA: Cadaver correlation of peroneal tendon changes with magnetic resonance imaging. Foot Ankle 11: 384, 1991.
Buschmann WR, Cheung Y, Jahss MH: Magnetic resonance imaging of anomalous leg muscles: accessory soleus, peroneus quartus and the flexor digitorum longus accessorius. Foot Ankle 12: 109, 1991.
Thomas JL, Lopez-Ben R, Maddox J: A preliminary report on intra-sheath peroneal tendon subluxation: a prospective review of 7 patients with ultrasound verification. J Foot Ankle Surg 48: 323, 2009.
Park HJ, Cha SD, Kim HS, et al: Reliability of MRI findings of peroneal tendinopathy in patients with lateral chronic ankle instability. Clin Orthop Surg 2: 237, 2010.
Donley BG, Leyes M: Peroneus quartus muscle: a rare cause of chronic lateral ankle pain. Am J Sports Med 29: 373, 2001.
The peroneus quartus muscle is an accessory muscle seen in the lateral compartment of the lower leg. Although the peroneus quartus muscle is asymptomatic in general, it sometimes becomes pathologic. We present the rare case of bilateral ankle pain with crepitation caused by the peroneus quartus muscle. Magnetic resonance imaging should be considered to assist with diagnosing this condition. Foot and ankle surgeons should consider it in the preoperative differential diagnosis when patients present with posterior ankle pain.