Anatomy Of The Peroneus Brevis Muscle

Courtesy: Prof Nabile Ebraheim, University of Toledo, Ohio, USA

• The peroneus brevis muscle runs along the lateral aspect of the lower leg

• It lies deep to the peroneus longus muscle

• Compared to peroneus longus, it has:

  • A shorter muscle belly

  • A shorter tendon

• It is located within the lateral compartment of the leg

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Lateral Compartment of the Leg

• Contains two muscles:

  • Peroneus brevis

  • Peroneus longus

• Innervation:

  • Both muscles are supplied by the superficial peroneal (fibular) nerve

• Blood supply:

  • Supplied by the peroneal artery

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Origin and Insertion

Peroneus Brevis

• Origin:

  • Inferior two-thirds of the lateral surface of the fibular shaft

• Insertion:

  • Lateral aspect of the base of the 5th metatarsal

• The muscle becomes tendinous approximately 2–4 cm proximal to the tip of the lateral malleolus

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Peroneus Longus (for comparison)

• Origin:

  • Head of fibula

  • Upper two-thirds of the lateral fibular shaft

  • Anterior and posterior intermuscular septa of the leg

• Insertion:

  • Plantar posterolateral surface of the medial cuneiform

  • Base of the first metatarsal

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Peroneal Tendons

• The peroneus brevis and longus tendons:

  • Share a common synovial sheath

  • Curve around the posterior aspect of the lateral malleolus

• At the level of the calcaneus:

  • The peroneal tubercle separates the two tendons

• Retinacular support:

  • Superior peroneal retinaculum

    • Located over the posterior aspect of the distal 3 cm of fibula

  • Inferior peroneal retinaculum

    • Continuous with the inferior extensor retinaculum

• Behind the fibula:

  • The tendons lie within a bony groove known as the peroneal groove

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Innervation

• Superficial peroneal nerve

• Root values: L5, S1, S2

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Functions

• Peroneus brevis

  • Primary evertor of the hindfoot

• Peroneus brevis and longus (together)

  • Assist in plantarflexion of the ankle

  • Contribute to lateral ankle stability

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Clinical Correlation

• Longitudinal split tear of the peroneus brevis

  • Often associated with peroneal tendon subluxation or instability

• Avulsion fracture of the base of the 5th metatarsal

  • Caused by the traction force of the peroneus brevis tendon

• Peroneus brevis pathology is commonly implicated in:

  • Chronic lateral ankle pain

  • Recurrent ankle sprains

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Key Take-Home Points

• Peroneus brevis is a key lateral stabilizer of the ankle

• It plays a critical role in hindfoot eversion

• Its insertion at the 5th metatarsal explains common avulsion injuries

• Understanding tendon anatomy is essential for diagnosing:

  • Lateral ankle instability

  • Peroneal tendon disorders