Anomalous Pattern of Tendinous Slips of Peroneus Tertius and Extensor Digitorum Longus Muscles in the Foot- A Clinically Important Variation

Abstract

The peroneus tertius (PT) is a small muscle with a small single tendon which gets inserted to the dorsal surface of the 5 th metatarsal base. Normally, the tendon of extensor digitorum longus (EDL) muscle divides into 4 slips on the dorsum of the foot which go to the lateral 4 toes. Variations in the tendons of these muscles are very rare. We observed a case where the tendon of EDL divided into only 3 slips which were inserted into the 2 nd , 3 rd and 4 th toes through dorsal digital expansion. The PT tendon was quite thick and it divided into 2 slips. The lateral slip was getting inserted to the dorsal surface of the 5 th metatarsal base and medial slip was continuing on to the little toe to form the dorsal digital expansion. This variation was observed during routine dissection on the left lower limb of about 55 year old female cadaver. Such anomalies are important clinically to the treating surgeon, being a tendon of importance in normal function and surgeries of the foot. Functional significance and the clinical relevance of the variations are discussed.

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

“…No incidence of Type I or Type III was observed in the present study. A case report of anomalous insertion of PT muscle was reported by Abhinitha et al 8 . They observed distal end PT muscle dividing into medial and lateral slips.…”