The Peroneal Nerve
Place the recording electrode over the Extensor Digitorum Brevis (EDB) muscle, over the lateral aspect of the dorsum of the foot, located by asking the subject to wiggle their toes. Place the reference electrode over the base of the little toe.
Stimulate the nerve distally at the ankle, lateral to the anterior tibial tendon; stimulate it proximally in the lateral popliteal space.
In the work-up of a peroneal neuropathy, stimulation below the fibular head should be done to rule out lesions at tat level. When an absent or a low response is evoked on stimulation of the peroneal nerve at the ankle (smaller than the response obtained from proximal stimulation), stimulate the area behind the lateral malleolus to pick up a variant in the innervation of the extensor digitorum brevis by way of the accessory peroneal nerve. If stimulation of either site does not give a response, then study of the anterior tibial muscle may give information of peroneal nerve function.
The peroneal nerve is most frequently involved, by pressure or injury, at the fibular head, causing the classical foot drop; as part of a sciatic nerve injury; or at the ankle in the anterior tarsal tunnel (deep branch).