Lateral Anatomical Structure of the Extensor Hallucis Brevis Muscle

Description

Laterally on the dorsum of the foot, the extensor hallucis brevis (EHB) sits deep to the extensor digitorum brevis, arising from the superolateral surface of the calcaneus just anterior to the calcaneal tuberosity. Its short muscle belly courses anteriorly and medially toward the hallux, transitioning into a tendon that passes dorsal to the talonavicular region and in close apposition to the anterior ankle joint capsule and extensor retinacula. Superiorly, the distal tibia and talus define the ankle mortise, while the EHB lies distal to the lateral malleolus and lateral to the dorsalis pedis artery as it continues toward the first ray. Clinical relevance centers on the crowded anterior ankle and dorsal midfoot, where extensor tendons, retinaculum, and capsular tissue share limited space. Painful swelling over the dorsolateral midfoot after inversion injury or repeated plantarflexion can represent EHB strain, tenosynovitis, or synovial irritation from the talonavicular or subtalar joint, and this view helps separate those entities from peroneal tendon pathology that sits more posterior to the lateral malleolus. A useful landmark. The EHB tendon also becomes pertinent during dorsal approaches to the talonavicular joint and when interpreting ultrasound or MRI for dorsal midfoot ganglion cysts that track along the extensor tendon sheaths. Educators can pair this image with cadaver lab teaching in lower-limb anatomy, emphasizing dorsal foot compartment relationships and tendon routing to the hallux. It also suits atlases, surgical technique chapters, and radiology teaching files that need a clear lateral reference for the anterior ankle joint capsule, extensor retinaculum, and short hallux extensor anatomy. Anatomical accuracy verified by SciePro's Medical Advisory Board.