Muscle · Foot

Extensor digitorum brevis

Musculus extensor digitorum brevis

The only muscle on the top of the foot. It arises from the front of the heel bone, runs forward and inward as a flat belly, and divides into three tendons that join the long extensor tendons of the second, third and fourth toes. Its belly forms a soft rounded fullness on the outer side of the foot just in front of the ankle — a normal, symmetrical feature of the dorsum that is easily read as a lump by anyone who has never looked closely at that part of the foot. Its job is to straighten the middle three toes independently of the long extensors coming down from the leg.