Common fibular nerve

At a glance

English

Common fibular nerve

Latin (TA2)

Nervus fibularis communis

System

Nerve

Region

Lower limb

Side

Paired, left and right

About the common fibular nerve

The common fibular (common peroneal) nerve carries fibres from L4 to S2 and is the lateral of the two branches into which the sciatic nerve divides, usually at the top of the popliteal fossa. It runs downwards and outwards along the medial edge of biceps femoris and its tendon, crosses the lateral head of gastrocnemius and leaves the fossa at its lateral corner. It then winds forwards round the fibular neck, lying directly on bone beneath the skin, passes into fibularis longus and divides there into the superficial and deep fibular nerves.

Before it divides it gives off several branches. Two are cutaneous: the lateral sural cutaneous nerve, for skin over the upper lateral calf, and the sural communicating branch, which runs over the back of the calf to join the sural nerve. Three are articular: the superior lateral and inferior lateral genicular nerves, which travel with the matching arteries above the lateral femoral condyle and above the fibular head, and the recurrent genicular nerve, which arises at the point of division and climbs beside the anterior recurrent tibial artery towards the front of the knee and the top of tibialis anterior. In the thigh, the fibular part of the sciatic nerve also supplies the short head of biceps femoris, the only muscle above the knee it serves.

Through its two terminal branches the nerve controls the extensors of the anterior compartment, which lift the foot and toes, and the fibular muscles of the lateral compartment, which evert the foot, as well as most skin of the lower lateral leg and the top of the foot.

Its exposed course at the fibular neck makes it the lower limb nerve most often injured on its own. Habitual leg crossing, long bed rest, tight casts, prolonged kneeling or squatting, sudden weight loss, a blow to the side of the knee or a fibular fracture can all damage it. The result is foot drop: the foot hangs, the toes drag and the patient lifts the knee high to clear the ground, with numbness over the lower lateral leg and dorsum of the foot. Surgical decompression through an incision over the fibular neck can release a trapped nerve.

Course and supply

Arises from

The lateral terminal division of the sciatic nerve (L4-S2), usually at the apex of the popliteal fossa.

Ends in

Divides beside the fibular neck, within fibularis longus, into the superficial and deep fibular nerves.

Supplies

Through its branches, motor to the anterior and lateral compartment muscles of the leg (and, via the fibular part of the sciatic, the short head of biceps); sensory to the lateral leg, dorsum of foot and knee joint.