Extensor digitorum brevis
Extensor digitorum brevis is the only muscle located on the dorsum of the foot. It originates primarily from the superolateral surface of the calcaneus, just anterior to the sinus tarsi, and inserts dorsally into the medial four toes. Note that extensor digitorum brevis does not insert into the fifth toe. Asking your patient to extend their toes at the interphalangeal and metatarsophalangeal joints will assist in identifying this muscle and its tendons of insertion. The muscle belly will become prominent on the dorsum of the foot just lateral to the tendons of extensor digitorum longus and peroneus tertius. It will be located medial to the lateral malleolus however.