Accessory Peroneal Muscle: A Case Report of an Anomolous Symptomatic Peroneus Quartus Muscle


  • Matthew Sperle, MAT, ATC Oklahoma State University Center for Health Sciences
  • Aric Warren, EdD, ATC Oklahoma State University Center for Health Sciences College of Osteopathic Medicine (OSU-COM)
  • Kevin Middlemist, DO Oklahoma State University Center for Health Sciences
  • Jaclyn Jones, DO Hillcrest Medical Center


Accessory peroneal muscle, peroneus quartus, anatomical variant, surgical repair


Introduction: A 26-year old Caucasian female presented to the clinic with chronic pain and discomfort in the left ankle after a fall. Chief complaints were lateral ankle pain, perceived weakness, and ankle instability. The patient presented with full range of motion and strength despite persistent tenderness along the peroneal tendons. Initial treatment for the tendinopathy consisted of protected immobilization in a walker boot with anti-inflammatory medication. Unresolved pain and tenderness led to subsequent imaging studies that revealed a split-tendon tear of the peroneus brevis. The patient underwent an open repair of the left peroneus longus and brevis tendons to reduce discomfort. An accessory peroneal tendon (peroneus quartus) with an abnormal calcaneal insertion was discovered during the procedure and excised. Surgical exploration determined good health of the peroneal tendons. Conclusion: It was suspected that the anatomical variant contributed to the patient’s lateral ankle pain. Surgical ablation of the accessory peroneal muscle produced a complete recovery and resolution of symptoms. This specific case report is unique due to the discovery of the variant accessory muscle and its location within the affected extremity.






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