Fibularis (peroneus) longus

Anatomy

Origin:
Head and upper two-thirds of the lateral surface of fibula and the intermuscular septa.

Insertion:
Lateral surface of the medial cuneiform and the base of the 1st metatarsal.

Key relations:
-One of the two muscles of the lateral compartment of the leg.
-The fibularis longus tendon passes posterior to the lateral malleolus along the lateral surface of the calcaneus, directly posterior to the fibularis brevis tendon. The two tendons lie deep to the inferior fibular retinaculum.
-The fibularis longus tendon passes diagonally across the sole of the foot.

Functions

-Everts the foot.
-Plantarflexes the ankle joint.
-Supports the lateral longitudinal and transverse arches of the foot e.g. walking on uneven surfaces..

Supply

Nerve Supply:
Superficial fibular (peroneal) nerve (L5, S1).

Blood Supply:
-Fibular (peroneal) artery
–Anterior tibial artery.

Clinical

Peroneal tendinopathy involves inflammation or injury (e.g a small tear) to the two peroneal tendons (peroneus brevis and longus). The patient may present with pain and inflammation or tenderness on the outside of the ankle or heel, which is worsened by activity, by passive inversion, by active eversion and by pressure applied to the two peroneal tendons. Causes of peroneal tendinopathy include repetitive overuse injuries e.g basketball, acute trauma to the ankle and overpronation of the foot.

Treatment involves rest, NSAIDs, stretching the peroneal and calf muscles and surgery in more severe cases.

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