Herniated Nucleus Pulposus can be diagnosed by clinical findings, myelography, diskography, and Electromyography.

The electromyographic findings include increased insertional activity, increased polyphasic potentials, bizarre high frequency discharges. Fibrillation and positive sharp potentials and characteristic "chugging sound".

Motor and sensory nerve conduction studies in cases of root compression by disc herniation were reported as not impaired in the periphery, and reduced amplitudes of motor nerve action potentials due to axonal degenerations were reported only.

Nerve conduction velocities, amplitudes and durations of motor and sensory nerve action potentials were studied, and the mean values of affected and unaffected extremities were compared in 23 HNP suspected patients, 21 male and 2 female.

The results were as follows:

1. Amplitudes of peroneal motor nerve action potentials were lowered in affected extremities, significantly (p<0.005, Table 1).

2. Conduction velocities of tibial sensory nerves were reduced in affected extremities, significantly (p<0.005, Table 4).