Morphological Variations of Peroneus Tertius: A Cadaveric Study with Anatomical and Clinical Consideration

Objective: The objective of this study was to highlight variations in the morphology of peroneus tertius muscle owing to its evolutional, academic, and clinical importance.
Methods: Sixty-six disarticulated lower limbs were used to study the morphological variations of peroneus tertius (PT) muscle like absence, duplication, accessory PT muscle, and abnormal site of origin and insertion. Detailed dissection was performed to study the proximal and distal attachments of PT muscle, and observed variations were recorded.
Results: Twelve out of 66 specimens showed the following variations, accessory and duplicate peroneus tertius was observed in one specimen (1.52%) each. We categorized variations in insertions into six types. The most common variation in the present study was type II (84.8%) followed by type VI (10.6%). Type IIa and IV were observed in one specimen (1.52%) each.
Conclusion: The present study highlights variations in both origin and insertion of PT muscle. We have also postulated a new modified classification which is the first of its kind to highlight two new additional variations in insertions existing in the current literature. Awareness of the above variations would be useful to surgeons performing tendon transfers, tendoplasty, and resection surgeries of the foot.