[Antidromic sensory action potentials of the median and ulnar nerve.--Normal value and discussion of methodology (author's transl)].

The sensory conduction velocities of the median and ulnar nerve and the amplitudes of the evoked nerve action potentials were measured and evaluated statistically in 116 healthy subjects with the antidromic technique. Both conduction times and amplitudes were correlated to age and to the nerve segment studied (finger--wrist or wrist--elbow). Moreover amplitudes varied with the distance between the recording electrodes; in spite of their great interindividual differences they may be of diagnostic help. In clinical electrophysiology this method is useful in revealing especially minor injuries of the brachial nerves and plexus with little or no involvement of the motor fibres. In such cases the antidromic action potentials can be registered quickly, reliably and nearly painless. The orthodromic technique is much more complicated, an averager or some other technical supplement often is necessary for recording clearly visible potentials, because the amplitudes are lower. On the other hand, orthodromic potentials may still detectable with an averager in severe nerve lesions where antidromic potentials are absent.