Peroneus Tertius

Peroneus tertius
Muscles of the front of the leg. (peroneus tertius visible at center left)
Details
Origin	distal anterior surface of the fibula also the interosseous membrane
Insertion	dorsal surface of metatarsal 5
Artery	anterior tibial artery
Nerve	deep fibular nerve
Actions	dorsiflexion and eversion of the foot
Identifiers
Latin	Musculus peronaeus tertius, musculus fibularis tertius
TA	A04.7.02.039
FMA	22538
Anatomical terms of muscle []

The peroneus tertius (also known as fibularis tertius) is a muscle of the human body located in the lower limb.

The muscle arises from the lower third of the anterior surface of the fibula (anterior compartment of lower leg); from the lower part of the interosseous membrane; and from an intermuscular septum between it and the peroneus brevis muscle. The septum is sometimes called the intermuscular septum of Otto.

The tendon, after passing under the superior extensor retinaculum of foot and inferior extensor retinaculum of foot in the same canal as the extensor digitorum longus, is inserted into the dorsal surface of the base of the metatarsal bone of the fifth digit.

It is innervated by the deep fibular nerve, unlike the other peroneal muscles which are innervated by the superficial fibular nerve, since the peroneus tertius is a member of the anterior compartment.

Its action is that of weak dorsiflexion of the ankle joint and to evert the foot at the ankle joint.

The muscle may be absent in humans; it is seldom found in other primates, a fact that has linked its function to efficient terrestrial bipedalism.

Bones of the right foot (dorsal surface).

The mucous sheaths of the tendons around the ankle (lateral aspect).

Dorsum of Foot. Deep dissection.

Dorsum of Foot. Deep dissection.

This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)