Located on the top portion of the foot, the extensor hallucis brevis muscle assists in moving the big toe. This digit is the closest to the foot's instep and it is often referred to as the first digit of the foot.
The muscle inserts into the digit's proximal phalanx, which is the bone the makes up the lower part of the big toe. It extends from here to its point of origin in the heel bone.
The dorsalis pedis artery services the extensor hallucis brevis muscle with oxygenated blood and runs the length of the tibia, or shinbone.
The deep fibular nerve innervates the muscle. Both the artery and the nerve also serve other muscles on the dorsal (top) side of the foot.
The extensor hallucis brevis muscle is closely associated with the extensor digitorum brevis, which helps extend the rest of the foot's toes. Still, the extensor hallucis brevis works only to extend the large toe. The flexor hallucis brevis controls flexing the large toe. The rest of the toes are flexed by the flexor digitorum longus and brevis muscles.