Extensor Hallucis Brevis Muscle

The extensor hallucis brevis muscle arises from the dorsal side of the calcaneous to insert at the big toe's proximal phalanx, serving to help extend the big toe. The hallux (plural, hallucis) are muscles pertaining to the big toe. The extensor hallucis longus are muscles used in extending the toe; the flexor hallucis longus are used in flexing it and moving it to the side.