Deep fibular (peroneal) nerve
The deep fibular (peroneal) nerve is one of two terminal branches of the common fibular (peroneal) nerve, the other being the superficial fibular (peroneal) nerve.
The deep fibular nerve is located in the anterior compartment of the leg. It runs through the interosseous membrane and descends down the leg, between the extensor muscles of the foot, for which it provides supply.
The nerve terminates around the ankle joint by dividing into lateral and medial terminal branches which innervate the muscles and skin of the foot.
This article will discuss the anatomy and function of the deep fibular (peroneal) nerve.
|Origin||Nervus fibularis communis (L4-S2)|
|Branches||Rami musculares, rami articulares, ramus lateralis, ramus medialis|
Motor: Tibialis anterior, extensor digitorum longus, extensor hallucis longus, fibularis tertius, extensor digitorum brevis, extensor hallucis brevis muscle
Sensory: skin of web between the first two digiti pedis, articulatio talocruralis, articulatio tarsalis and articulationes metatarsophalangeae
Origin and course
The common fibular nerve terminates with a bifurcation between the fibula and the proximal part of fibularis longus, providing two terminal branches: the deep fibular (peroneal) nerve and the superficial fibular (peroneal) nerve.
From its origin in the lateral compartment of the leg, the deep fibular nerve runs anteriorly, deep to the extensor digitorum longus, and onto the anterior surface of the interosseous membrane of the leg. From here, the nerve descends within the anterior compartment of the leg, along with the anterior tibial artery.
At first, the nerve runs lateral to the artery, but in the distal portion of the leg, the nerve becomes anterior to the anterior tibial artery. Just proximal to the ankle joint, the nerve is again positioned lateral to the artery and together, they enter the dorsum of the foot deep to the extensor retinaculum. Distal to the ankle, the nerve terminates by dividing into lateral and medial terminal branches.
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Branches and innervation
The deep fibular nerve provides several muscular and articular branches on its path through the anterior compartment of the leg. The muscular branches innervate the following muscles: tibialis anterior, extensor digitorum longus, extensor hallucis longus and fibularis tertius. The articular branches innervate the ankle joint.
Additionally, the deep fibular nerve provides two terminal branches: medial and lateral terminal branches.
- The medial terminal branch courses distally through the dorsal compartment of the foot alongside the dorsalis pedis artery, which lies medial to it. At the first interosseous space, the nerve merges with the medial branch of the superficial fibular nerve. The medial terminal branch provides cutaneous innervation to the adjacent sides of the first two toes as well as the web space between these digits. In addition, the medial branch of the deep fibular (peroneal) nerve gives an articular branch to the first metatarsophalangeal joint.
- The lateral terminal branch runs deep to the extensor digitorum brevis muscle as it crosses the ankle joint. It supplies the extensor digitorum brevis and extensor hallucis brevis muscles, the tarsal joint as well as the middle three metatarsophalangeal joints.
The most common isolated injury to the deep fibular nerve is due to compartment syndrome. This syndrome is caused by bleeding or swelling within an enclosed bundle of muscles – known as a muscle compartment. The muscle compartment does not have the ability to increase its size and volume capacity due to surrounding tough fascia. Thus, any major swelling leads to the compression of the neurovascular structures that run through the compartment.
Patients with compartment syndrome of the anterior leg compartment usually present with weakness of ankle dorsiflexion and extension of all toes but normal foot eversion. Sensory impairment is confined to the first interdigital web space.