Anatomic origin of the cervical N13 potential evoked by upper extremity stimulation

There is a large consensus, based on converging evidence, that N13-recorded at lower cervical levels has a segmental postsynaptic origin in the gray m atter of the cervical cord and that because of the orientation of its dipol e field, the Cv6-anterior cervical derivation should be used whenever the d iagnostic problem requires that this potential be assessed selectively in t erms of latency and amplitude. The diagnostic utility of the lower cervical N13 recording in dorsal horn deafferentation and in lesions at the Cv6-Cv8 metameric levels has been validated in all types of cervical cord lesions. Unfortunately, such clear-cut conclusions do not apply to the N13 potentia l recorded at upper cervical levels. Currently, this component is not consi dered to provide enough reliable information, in addition to P13-P14 scalp recordings, to be used routinely in the diagnosis of cervicomedullary lesio ns.