The only branch which cannot be investigated neurophysiologically. Involvement of all distal nerves by peripheral neuropathy will also produce hand numbness. EMG remains the electrophysiologic procedure for radiculopathy, but is unable to detect pure sensory radicular lesions. Dermatomals somatosensory evoked potentials may be used in sensory radiculopathies, though the difficulties encountered in performing these tests make them suitable only in selected cases. An imaging study, usually magnetic resonance imaging, is usually required when a central nervous lesion is suspected.
Evoked potentials are useful when it becomes necessary to test the integrity of the sensory pathway.