Where does the Extensor Digitorum Brevis typically insert?

• A. Base of the distal phalanx
• B. Base of the proximal phalanx
• C. Across the extensor hood of the toes
• D. Along the dorsal aspect of the metatarsophalangeal joints

Answer: (B)

Extensor digitorum brevis is a short dorsal foot muscle whose main role is to help extend the toes at the metatarsophalangeal joints. It originates from the calcaneus and splits into slips that insert on the bases of the proximal phalanges of the second through fourth toes. This insertion lets the muscle lift the proximal phalanges upward, producing toe extension at the MTP joints. Some slips may contribute to the extensor expansions, but the primary attachment is at the base of the proximal phalanges, which is why that site is the correct choice. Inserting on the distal phalanx or simply along the dorsal aspect of the MTP joints would not align with the muscle’s typical attachment and function.