Extensor Digitorum Brevis

Extensor Digitorum Brevis

The Extensor Digitorum Brevis originates from the anterior part of the dorsal surface of the calcaneus. Four tendons insert into the proximal phalanx of the big toe and long extensor tendons to toes 2, 3, and 4. The medial part of the muscle is known as the extensor hallucis brevies and ends in a tendon that is inserted into the dorsal surface of the base of the proximal phalanx of the big toe.

The other three tendons insert into the lateral side of the tendons of the extensor digitorum longus of toes number 2, 3, and 4. The extensor digitorum brevis helps to extend the first four digits. The extensor digitorum brevis is innervated by the deep peroneal nerve (predominantly L5 nerve root). The EDB muscle has the same innervation as a disc herniation at L4-L5 which will also involve the L5 nerve root. It is probably the only muscle of the foot that is innervated by the deep peroneal nerve. The deep peroneal nerve supplies sensation to the first web space. The EDB is the only muscle on the foot that makes a fleshy enlargement anterior to the lateral malleolus. The extensor digitorum brevis can cause pain on the top of the foot. Irreducible dislocation of the medial subtalar joint can result from interposition of the extensor digitorum brevis muscle. Irreducible dislocation of the lateral subtalar joint can result from interposition of the tibialis posterior tendon.