Accessory deep peroneal neuropathy: collision technique diagnosis.

Accessory deep peroneal nerve (ADPN), a common anatomic variant, is traditionally suspected when common peroneal nerve stimulation evokes a greater amplitude extensor digitorum brevis compound muscle action potential than deep peroneal nerve (DPN) stimulation. Posterolateral ankle stimulation over the ADPN is confirmatory. We report a rare patient with ADPN neuropathy in whom the collision technique was necessary to confirm the presence of an ADPN and to distinguish between neuropathy of the ADPN and the DPN.