English

Abstract

INTRODUCTION: Fibularis tertius (FT) was formerly called as the peroneus tertius 1 . FT muscle is a relatively small unipennate muscle found in the anterior compartment of the leg. It assists in dorsiflexion and eversion of foot 2 . The FT muscle originates from the distal third or more of the medial surface of fibula, the adjoining anterior surface of the interosseous membrane and the anterior crural intermuscular septum. Thereafter, tendon runs beneath the superior extensor retinaculum, inferior extensor retinaculum and gets inserted on the medial aspect of the dorsal surface of the base of the fifth metatarsal. FT muscle is supplied by the deep peroneal nerve (2, 3, and 4) . FT has been described as a part of the extensor digitorum longus (EDL) muscle in classical textbooks 2 . CASE REPORT: During routine dissection for the first MBBS students, we observed that the peroneus tertius was absent on the dorsum of the Right lower limb of a 50 years old, donated embalmed male cadaver in the Department of Anatomy, Lady Hardinge Medical College, New Delhi, India. Both the limbs were carefully observed and examined to differentiate the absence of FT muscle. There was no scar mark or sign of injury on the limb. The other muscles of the compartment were present normally with their normal anatomical features. The photographs of the dorsum of the foot were taken for proper documentation and for ready reference. The absence of the peroneus tertius is very rare and not found in literature. Usually, the peroneus tertius is involved in dorsiflexion and eversion of the foot.