Where does the extensor digitorum brevis insert?

Where does the extensor digitorum brevis insert?

• A. Extensor expansion of FDL near the MPJ
• B. Base of the proximal phalanx of the great toe
• C. Calcaneal tuberosity
• D. Lateral aspect of the metatarsal

Answer: (A)

The extensor digitorum brevis attaches where it can influence toe extension through the extensor mechanism: it inserts into the extensor expansions of the toes, specifically digits two to four, near the metatarsophalangeal joints. Its slips merge with the tendons of the extensor digitorum longus to form the extensor hood over the proximal phalanges, enabling coordinated extension at the MP joints and aiding extension of the IP joints via the expansion. This differs from other potential sites: the base of the proximal phalanx of the great toe is where the extensor hallucis brevis would insert, not the extensor digitorum brevis. The calcaneal tuberosity is the origin area for the muscle, not its insertion, and the lateral aspect of a metatarsal is not where these slips attach.

The extensor digitorum brevis attaches where it can influence toe extension through the extensor mechanism: it inserts into the extensor expansions of the toes, specifically digits two to four, near the metatarsophalangeal joints. Its slips merge with the tendons of the extensor digitorum longus to form the extensor hood over the proximal phalanges, enabling coordinated extension at the MP joints and aiding extension of the IP joints via the expansion.

This differs from other potential sites: the base of the proximal phalanx of the great toe is where the extensor hallucis brevis would insert, not the extensor digitorum brevis. The calcaneal tuberosity is the origin area for the muscle, not its insertion, and the lateral aspect of a metatarsal is not where these slips attach.