fibularis tertius
A muscle located in the lower limb that arises from the lower third of the anterior surface of the fibula; from the lower part of the interosseous membrane; and from an intermuscular septum between it and the peroneus brevis and inserted into the dorsal surface of the base of the metatarsal bone of the 5th digit. It is innervated by the deep fibular nerve. Its action is that of weak dorsiflexion of the ankle joint and to evert the foot at the ankle joint.