Sensory nerve action potential

Since the ganglion of the sensory nerves lies within the neural foramen, preganglionic lesions (injury to the nerve root proximal to the neural foramen, e.g. root compression by herniated disc or root avulsion) does not affect the cell body, and therefore the distal SNAP is unaffected.

Postganglionic lesions (distal to the neural foramen, e.g. peripheral nerve injury) reduces SNAP amplitudes and/or slows the sensory conduction velocity.

F-wave: stimulation of a nerve causes orthodromic and antidromic conduction. Some anterior