Deep fibular nerve

The deep fibular nerve (deep peroneal nerve) begins at the bifurcation of the common peroneal nerve, between the fibula and upper part of the fibularis (peronæus) longus, passes infero-medially, deep to extensor digitorum longus, to the anterior surface of the interosseous membrane, and comes into relation with the anterior tibial artery above the middle of the leg; it then descends with the artery to the front of the ankle-joint, where it divides into a lateral and a medial terminal branch.

It lies at first on the lateral side of the anterior tibial artery, then in front of it, and again on its lateral side at the ankle-joint.

In the leg, the deep peroneal nerve supplies muscular branches to the tibialis anterior, extensor digitorum longus, fibularis (peronæus) tertius, and extensor hallucis longus (propius), and an articular branch to the ankle-joint.

Lateral terminal branch
The lateral terminal branch (external or tarsal branch) passes across the tarsus, beneath the extensor digitorum brevis, and, having become enlarged like the dorsal interosseous nerve at the wrist, supplies the extensor digitorum brevis.

From the enlargement three minute interosseous branches are given off, which supply the tarsal joints and the metatarsophalangeal joints of the second, third, and fourth toes.

The first of these sends a filament to the second interosseus dorsalis muscle.

Medial terminal branch
The medial terminal branch (internal branch) accompanies the dorsalis pedis artery along the dorsum of the foot, and, at the first interosseous space, divides into two dorsal digital nerves (nn. digitales dorsales hallucis lateralis et digiti secundi medialis) which supply the adjacent sides of the great and second toes, communicating with the medial dorsal cutaneous branch of the superficial peroneal nerve.

Before it divides it gives off to the first space an interosseous branch which supplies the metatarsophalangeal joint of the great toe and sends a filament to the first Interosseous dorsalis muscle.