An anatomic variant insertion of peroneus longus in a cadaver – a case report

Introduction Peroneus longus is one of the two muscles in the lateral compartment of the leg [1.] It arises from head of fibula, proximal 2/3 of lateral surface of fibula, deep surface of fascia cruris, anterior and posterior crural intermuscular septa and few fibers from lateral condyle of tibia. The tendon inserts by two slips. One is inserted on the lateral side of base of first metatarsal and the other on the medial cuneiform [2]. The function of peroneus longus is the eversion and plantar flexion at the ankle joint and also stabilization of subtalar motion [1, 3, 4]. Orthopedic pathologies related to the peroneus longus insertion may be tendinitis, tenosynovitis, dislocation, acute rupture, chronic tear, and avulsion fractures. The study of peroneus longus tendon insertion is clinically important because of its importance in maintaining the arch of the foot [5]. The use of an accessory tendon obviates the sacrifice or weakening of a tendon that is used for routine function of the foot and the ankle [6]. Morphologically, peroneus longus should be inserted on the fibular side of the foot. Peroneus longus has shifted its insertion from the base of the fibular digit, across the sole, to the base of tibial digit and finally also to the medial cuneiform. The migration of the tendon of muscle across the sole of the foot from fibular to the tibial border is a gradual process in the ontogeny of man and a repetition of the phylogeny of the muscle. The morphological evolution of the muscle can readily be followed in the mammalian series. The muscle may get inserted anywhere between these two digits and also give fibrous expansions to the neighboring structures [7].