peroneusbrevis

Peroneus brevis, also known as fibularis brevis, is a muscle of the lateral compartment of the leg. It arises from the distal two-thirds of the fibula and adjacent intermuscular septa, and its tendon runs behind the lateral malleolus to insert on the tuberosity at the base of the fifth metatarsal. The muscle lies with the peroneus longus in the lateral compartment and contributes to movements of the foot.

Functionally, peroneus brevis everts the foot and assists in plantarflexion. It also helps stabilize the lateral aspect of the ankle and supports the transverse and longitudinal arches during locomotion, working together with the peroneus longus.

Innervation is provided by the superficial peroneal nerve (fibular nerve). Vascular supply comes from perforating branches of the fibular (peroneal) artery.

Clinical significance includes injuries such as peroneus brevis tendinopathy or tearing, often associated with ankle inversion injuries. The tendon can avulse the base of the fifth metatarsal, causing an avulsion fracture at its tuberosity (sometimes referred to in the context of fifth metatarsal fractures). Such injuries may contribute to lateral ankle instability and are diagnosed by imaging modalities like MRI or ultrasound. Treatment ranges from conservative measures (rest, immobilization, physical therapy) to surgical repair in cases of tendon rupture or substantial avulsion.