Superficial fibular nerve

At a glance

English

Superficial fibular nerve

Latin (TA2)

Nervus fibularis superficialis

System

Nerve

Region

Lower limb

Side

Paired, left and right

About the superficial fibular nerve

The superficial fibular (superficial peroneal) nerve serves the leg's lateral, fibular compartment. It arises at the division of the common fibular nerve, beside the fibular neck on its outer side, within fibularis longus. It runs down through the fibular muscles, at first between fibularis longus and the bone and then, in the middle third, between fibularis longus and fibularis brevis. It comes forward to the front edge of brevis and lies in the groove between it and extensor digitorum longus, still beneath the deep fascia.

In the lower third of the leg the nerve pierces the deep fascia and becomes subcutaneous, usually at the junction of the middle and lower thirds and about a hand's breadth above the lateral malleolus. Here, or just above, it divides into the medial and intermediate dorsal cutaneous nerves, which cross the front of the ankle into the foot. The medial branch ends as digital nerves for the inner edge of the great toe and the facing sides of the second and third toes; the intermediate branch ends in digital nerves for the facing sides of the third, fourth and fifth toes.

Its muscular branches supply fibularis longus and brevis, which evert the foot and help steady the ankle. Its cutaneous branches cover the lower lateral leg and most of the top of the foot. The edges of that territory belong to other nerves: the saphenous nerve along the medial border, the sural nerve along the lateral border, the deep fibular nerve in the first web space, and the plantar nerves on the sole. Its medial branch communicates with the saphenous and deep fibular nerves, and its lateral branch with the sural nerve.

Injury weakens eversion and leaves the top of the foot numb, while sparing the first web space. The nerve is most vulnerable where it pierces the fascia, where it can be trapped, causing burning pain over the top of the foot, especially after ankle sprains. It is also at risk during ankle arthroscopy and surgery on fibular fractures, and its course is marked before placing lateral ankle portals. Pointing the foot downwards and inwards often makes it visible under the skin.

Course and supply

Arises from

The common fibular nerve, at its division beside the neck of the fibula within fibularis longus.

Ends in

Divides in the lower leg into the medial and intermediate dorsal cutaneous nerves, which end as dorsal digital nerves of the toes.

Supplies

Motor to fibularis longus and fibularis brevis (eversion); sensory to the lower lateral leg and most of the foot's dorsum and toes, sparing the first web space.