The common fibular nerve (common peroneal nerve; external popliteal nerve; peroneal nerve; lateral popliteal nerve), about one-half the size of the tibial nerve, is derived from the dorsal branches of the fourth and fifth lumbar and the first and second sacral nerves.
It descends obliquely along the lateral side of the popliteal fossa to the head of the fibula, close to the medial margin of the biceps femoris muscle. Where the common peroneal nerve winds round the head of the fibula, it is palpable.
Previous to its division it gives off articular and lateral sural cutaneous nerves.
The articular branches (rami articulares) are three in number:
Two of these accompany the superior and inferior lateral genicular arteries to the knee; the upper one occasionally arises from the trunk of the sciatic nerve.
The third (recurrent) articular nerve is given off at the point of division of the common fibular nerve; it ascends with the anterior recurrent tibial artery through the tibialis anterior to the front of the knee.
The lateral sural cutaneous nerve (n. cutaneus suræ lateralis; lateral cutaneous branch) supplies the skin on the posterior and lateral surfaces of the leg.
The motor branches:
As the common fibular nerve exits the popliteal fossa, it courses around the lateral aspect of the leg just below the head of the fibula. Here it is apposed with fibula and gives off two branches, the superficial fibular (peroneal) branch and deep fibular (peroneal) branch.
The superficial peroneal nerve supplies the muscles of the lateral compartment of the leg namely: peroneus longus and peroneus brevis. These two muscle help in eversion and plantar flexion of the foot.
The deep peroneal nerve also innervates intrinsic muscles of the foot including the extensor digitorum brevis and the extensor hallucis brevis.
Chronic peroneal neuropathy can result from, among other conditions, bed rest of long duration, hyperflexion of the knee, peripheral neuropathy, pressure in obstetric stirrups, and conditioning in ballet dancers. The most common cause is habitual leg crossing that compresses the common fibular nerve as it crosses around the head of fibula. Transient trauma to the nerve can result from peroneal strike.
Damage to this nerve typically results in foot drop, where dorsiflexion of the foot is compromised and the foot drags (the toe points) during walking; and in sensory loss to the dorsal surface of the foot and portions of the anterior, lower-lateral leg. A common yoga kneeling exercise, the Varjrasana has, under the name "yoga foot drop," been linked to foot drop.
Peroneal nerve decompression:
In the surgical treatment of fibular nerve compression, an incision is made over the neck of the fibula. Fascia surrounding the nerves to the lateral side of the leg is released.
Deep peroneal nerve decompression:
In the surgical treatment of deep fibular nerve entrapment in the foot, a ligament from the extensor digitorum brevis muscle that crosses over the deep peroneal nerve, putting pressure on it and causing pain, is released.
Front and posterior views of cutaneous nerves of the right lower extremity
A schematic of the sacral plexus showing the origin of the common fibular nerve (labeled at the bottom left)