Fibularis longus

Peroneus longus
Lateral aspect of right leg.
Peroneus longus labeled at right
Details
Origin	Upper part of lateral surface of shaft of fibula
Insertion	first metatarsal, medial cuneiform
Artery	fibular (peroneal) artery
Nerve	Superficial fibular (peroneal) nerve
Actions	plantarflexion, eversion, support arches
Antagonist	Tibialis anterior muscle, T.A. does Inversion and Dorsiflexion
Identifiers
Latin	Musculus peronaeus longus, musculus fibularis longus
TA	A04.7.02.041
FMA	22539
Anatomical terms of muscle []

In human anatomy, the peroneus longus (also known as fibularis longus) is a superficial muscle in the lateral compartment of the leg, and acts to evert and plantarflex the ankle.

The muscle, the longest and most superficial of the three fibularis muscles, is attached proximally to the head of the fibula and its 'belly' runs down most of this bone. It becomes a tendon that goes posteriorly around the lateral malleolus of the ankle, then continues under the foot to attach to the medial cuneiform and first metatarsal.

The terms Peroneus (i.e., Longus and Brevis) and Peroneal (i.e., Artery, Retinaculum) are derived from the Greek word Perone (pronounced Pair-uh-knee) meaning pin of a brooch or a buckle. In medical terminology, both terms refer to being of or relating to the fibula or to the outer portion of the leg.

It arises from the head and upper two-thirds of the lateral surface of the body of the fibula, from the deep surface of the fascia, and from the intermuscular septa between it and the muscles on the front and back of the leg; occasionally also by a few fibers from the lateral condyle of the tibia. Between its attachments to the head and to the body of the fibula there is a gap through which the common fibular nerve passes to the front of the leg.

It ends in a long tendon, which runs behind the lateral malleolus, in a groove common to it and the tendon of the fibularis brevis; the groove is converted into a canal by the superior fibular retinaculum, and the tendons in it are contained in a common mucous sheath.

The tendon then extends obliquely forward across the lateral side of the calcaneus, below the trochlear process, and the tendon of the fibularis brevis, and under cover of the inferior fibular retinaculum.