The peroneus tertius muscle may be called the fifth tendon and is part of the extensor digitorum longus. From the lower third of the fibula’s anterior surface, at the interosseous membrane’s lower portion and from an intermuscular septum amid the peroneus brevis and it, come the fibers that belong to this tendon.
The tendon enters the dorsal surface of the base of the little toe’s metatarsal bonemycontentbreak after it goes under the transverse and cruciate crural ligaments in the canal that also includes the extensor digitorum longus.
The deep fibular nerve activates the peroneus tertius muscle. This is not the case for the other peroneal muscles. The superficial fibular nerve activates them. This is because the peroneus tertius is part of the anterior compartment.
The peroneus tertius muscle functions to flip the foot at the ankle joint and has weak dorsiflexion of the ankle joint.