The extensor digitorum brevis is the only intrinsic muscle on the dorsum of the foot.
The medial aspect of the muscle forms a distinct slip which forms a thin tendon which crosses the dorsalis pedis artery, inserting into the dorsal base of the proximal phalanx of the hallux. This medial muscle is sometimes referred to as the extensor hallucis brevis.
The intrinsic muscles of the foot consist of one intrinsic muscle on the dorsal aspect of the foot (the extensor digitorum brevis), and 4 layers of muscles on the plantar aspect of the foot:
- 1st layer: abductor hallucis, flexor digitorum brevis, abductor digiti minimi
- 2nd layer: quadratus plantae, lumbricals
- 3rd layer: flexor hallucis brevis, adductor hallucis, flexor digiti minimi brevis
- 4th layer: dorsal interosseri, plantar interossei
- Superolateral calcaneus
- Base of proximal phalanx of great toe
- Lateral portion of tendons of extensor digitorum longus of toes II to IV
- Extension of great toe at metatarsophalangeal joint
- Flexion of toes II to IV
- Deep fibular nerve: S1,S2
- Dorsalis pedis artery