Peroneus brevis muscle

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The peroneus brevis muscle, also known as the fibularis brevis muscle, is a muscle in the lateral compartment of the leg. It lies deep/medial to the adjacent peroneus longus, and is a shorter and smaller muscle. Both brevis and longus travel together along the lateral aspect of the ankle within a shared synovial sheath . Together the tendons wrap around the lateral malleolus, specifically within the retromalleolar groove of the distal fibula.

At the level of the retromalleolar groove, the peroneus brevis tendon is located more anteromedial to the larger/rounder peroneus longus tendon. This can be remembered using the memory aid: "brevis closer to bone" (closer to the bones of the ankle, anteromedial to the peroneus longus tendon).

Summary

origin: lower two thirds of lateral surface of the fibula
insertion: lateral tubercle at base of fifth metatarsal
innervation: superficial fibular nerve
action: plantar flexion and eversion of foot

Gross anatomy

Origin

lower two thirds of the lateral shaft of the fibula

Insertion

the peroneal brevis tendon passes down the leg deep to the peroneus longus muscle, and curves around the lateral malleolus creating the retromalleolar groove
both peroneal tendons then course anteriorly toward the peroneal trochlea of the lateral calcaneum, at which point the tendon of brevis runs superior to the trochlea before terminating at the tubercle of the base of the fifth metatarsal