Morphology of nerve rootlets and spinal segments in the lumbosacral region: An anatomical study

The objective of the present study was to investigate the number of the spinal nerve rootlets and to determine the length of the spinal segments in the lumbosacral region of the spinal cord. Meticulous dissection was performed to expose the nerve rootlets. The nerve rootlets were macroscopically counted in the lumbosacral region and also communications between the nerve roots. The length of the spinal segments was measured in the lumbosacral region using vernier caliper. The data was analyzed statistically. The mean number of dorsal rootlets of the fifth sacral segment was significantly less compared to L5, S1, S2 and S3 segments. The dorsal rootlets were found to be thinner than ventral rootlets in the lower segment, however the ventral rootlets tend be thinner in the higher segments investigated. The present study also observed that the mean length of the third lumbar segment was highest and thereafter the length reduced gradually until the fifth sacral segment. The mean number of dorsal rootlets was more compared to the ventral rootlets on both right and left sides. There was a highly significant difference in the mean number of ventral and dorsal nerve rootlets in all the spinal segments investigated, except for third lumbar segment on the right side and third and fourth lumbar segments on left side. The morphometric data of the present study will be enlightening to the orthopedicians and neurosurgeons during their surgical practice. The details are also required to the neuroscientists and the researchers.