In general it is difficult to diagnose the level of lumbar disc herniation accompanied with transitional vertebra by neurological signs because of hard decision either L5 or S1 vertebra.It was made clear that the definite spinal nerve root passed through the intervertebral foramen below the transitional vertebra by demonstrating the Cul de sac and sacral nerve roots shadow by means of myelography with water soluble contrast media.That is, both L5 and S1 spinal nerve roots may pass through the intervertebral foramen below each transitional vertebral body when the number of lumbar vertebrae counts five and six respectively including the transitional vertebra.Therefore, the level of the herniated intervertebral disc accompanied with the transitional vertebra can be estimated by the neurological diagnostic method.