Which is the insertion of the extensor digitorum longus?

• A. Middle and distal phalanges of the 2nd to 5th toes
• B. Proximal phalanges of the 2nd to 5th toes
• C. Base of the 2nd to 5th metatarsals
• D. Distal phalanges of the great toe

Answer: (A)

The key idea is where the extensor digitorum longus attaches to the toes. It sends four tendons to the dorsal aspect of the lateral four toes, inserting into the middle and distal phalanges of toes 2 through 5 via the extensor expansions. This arrangement lets it extend those toes at the metatarsophalangeal and interphalangeal joints. The tendon that extends the great toe belongs to the extensor hallucis longus, not the extensor digitorum longus, which is why the distal phalanx of the big toe isn’t its insertion. The base of the metatarsals isn’t the insertion for this muscle.