Introduction: Unilateral or bilateral fusion of fifth lumber vertebra with the sacrum producing partial or complete sacralisation. due to many changes at this level .person suffers from low back pain with advancing age. Method: The present study was conducted on 30 dry human sacra and 30 dry fifth lumber vertebrae with the help of digital Varnier Caliper. Result: The transverse diameter of vertebra foramen is maximum in sacralisation as compared to L5 and S1. While, the transverse as well as anteroposterior diameter of vertebral body was maximum in sacralisation. Conclusion: Earlier diagnosis of sacralisation with the measurements of vertebral body and vertebral canal by CT scan in patients suffering from low back pain can be advised with proper exercises and precautions to strengthen the joints ,ligaments and muscles so that the disabilities could be prevented.