Deep fibular nerve
Nervus fibularis profundus
Also known as: deep peroneal nerve, anterior tibial nerve
The motor nerve of the anterior compartment of the leg, the ankle dorsiflexors and toe extensors, and of the dorsal foot muscles. Its only cutaneous territory is the first web space between the great and second toes.
Overview
The deep fibular nerve begins at the neck of the fibula, between the bone and fibularis longus. It pierces the anterior intermuscular septum and extensor digitorum longus and descends on the interosseous membrane with the anterior tibial artery. In the anterior compartment it supplies:
• tibialis anterior;
• extensor hallucis longus;
• extensor digitorum longus;
• fibularis tertius.
It crosses the front of the ankle deep to the extensor retinaculum, between the tendons of extensor hallucis longus and extensor digitorum longus, lateral to the dorsalis pedis artery. On the dorsum of the foot it gives:
• a lateral branch to extensor digitorum brevis and extensor hallucis brevis;
• a medial branch, which supplies the skin of the first dorsal web space, the adjacent sides of the great and second toes.
- Location
Anterior compartment of the leg on the interosseous membrane → front of the ankle → dorsum of the foot.
Anatomy
- Innervation
- Motor: tibialis anterior, EHL, EDL, fibularis tertius, extensor digitorum brevis and extensor hallucis brevis.
• Sensory: the first dorsal web space, and the ankle and tarsal joints.- Nerve roots
L4, L5, S1 (mainly L5).
- Course
Fibular neck → through EDL → interosseous membrane with the anterior tibial artery → deep to the extensor retinaculum (between the EHL and EDL tendons) → medial and lateral terminal branches on the dorsum of the foot.
Function
- Dorsiflexion of the ankle (tibialis anterior), clearing the toes during the swing phase
- Extension of the toes, including the great toe (EHL, EDL, EDB, EHB)
- Inversion assistance (tibialis anterior)
- Sensation of the first web space
Clinical significance
Anterior compartment syndrome
Raised pressure in the tight anterior compartment, after a tibial fracture, crush injury or exertion, compresses the deep fibular nerve and the muscles. Early warning signs are numbness of the first web space, pain out of proportion to the injury, and pain on passive plantarflexion of the toes. Emergency fasciotomy is required.
Anterior tarsal tunnel syndrome
Compression under the inferior extensor retinaculum, for example from tight shoe laces, ski boots or dorsal osteophytes, causes dorsal foot pain and first web space paraesthesia, sometimes with wasting of extensor digitorum brevis.
Compiled from standard anatomy and physiology references — see the Nervous System sources. For education only; not medical advice.