Background: In the lumbosacral region, anatomical variations occur with changes in the number of sacral vertebra by deletion of first sacral vertebra or by the union of fifth lumbar or first coccyx with sacrum. The fifth lumbar vertebra may be fused with the sacrum in the case of sacralisation, or the first sacral vertebra may be fused with fifth lumbar vertebra in the case of lumbarisation. This may cause serious problems during spinal surgery if we may fail to recognise the lumbosacral transitional vertebra. Materials and methods: We studied 117 dry human sacra of South Indian population of known sex. Out of 117 sacra, 70 male and 47 female. The sacra with four vertebral segments were selected and studied its morphology. Its features were carefully examined and noted. Result: A typical sacrum consisting of five segments was observed in 103 (88.03%) specimen, while presence of lumbarisation was noted in 2 (1.70%) cases and sacralisation was noted in 12 (10.25%) cases. Sacrum with 3 pairs of sacral foramina is 1.70%. Among the 2 specimen, we got 1 male and 1 female respectively Conclusion: Present study shows that the lumbarisation of first sacral vertebra leads to the formation of three pairs of sacral foramina, which is 1.70% in South Indian population. This awareness of lumbosacral transitional vertebra (LSTV) will help to understand its importance during surgical procedures and also in reporting the radiographs such as X-rays, CT and MRI.
Anatomic variations, congenital anomaly, lumbarisation, sacral foramina