Nerve supply to the posterior longitudinal ligament and the intervertebral disc of the rat vertebral column as studied by acetylcholinesterase histochemistry. II. Regional differences in the distribution of the nerve fibres and their origins.

Regional differences of the distribution and the origin of the nerve fibres of the posterior longitudinal ligament (PLL) and the intervertebral disc (IVD) were investigated by acetylcholinesterase (AchE) enzyme histochemistry in the rat. The deeper nerve network was well-developed at the lower thoracic and the upper lumbar vertebral levels, but it was hardly seen at the mid-thoracic level. This difference can be correlated with the extensibility of the PLL. The experimental study revealed that the AchE-positive nerve fibres in the PLL and the IVD were mostly derived from the spinal ganglia, that the superficial nerve network was supplied by the spinal ganglia bilaterally and polysegmentally, and that the deeper nerve network was supplied bilaterally but unisegmentally.