Introduction: palpation fails to give the correct location.

Introduction: Magnetic Resonance Imaging (MRI) is a non-invasive and radiation less imaging technique to visualize the internal parts of the body. MRI images of the spine and surrounding tissues are clearer and more detailed than other imaging methods. Spinal Cord is a vital organ within the body.  It is important to know the level of the Conus Medullaris (CM) to have a safe spinal block after an intervertebral injection. Counting the intervertebral spaces before spinal block is an important way to evade damage to the spinal cord. In two thirds of the patients; however, finding the intervertebral space with palpation fails to give the correct location. Several Studies stated that the level of the CM can be recognized on the MRI images perfectlyMaterials and Methods: This study was conducted among 122 adult (between 20-80 years old) patients who underwent MRI of whole spine or Lumbosacral spine. T2 STIR sagittal spin echo MRI images were considered for this study to determine the tip of the CM. The tip of the Conus Medullaris (CM) was defined as the most distal point of the spinal cord that could be visualized on the sagittal sequence. The data was analyzed by SPSS 20.0 software with P<0.05 indicating level of significance and using descriptive statistics. In accordance with the method of Saifuddin et al, a straight line perpendicular to the long axis of the spinal cord in the median sagittal plane subtended to the adjacent vertebra or disk space. And the position was defined in relation to the vertebra or disk space. Furthermore vertebral body was divided into 3 equal portions (upper, middle and lower third). Intervertebral disk space viewed as an independent section.Results: Mean level of CM was located at L1 middle in males and females. The mean CM to DST distance of male recorded as 157.37mm and mean CM to DST distance of female recorded as 144.30mm. Mann-Whitney U test showed no association between CM level and gender (p=0.998). According to the Kruskal-wallis H test there was no any association between CM level and age groups (p=0.590). There was statistically significant (p=0.000) negative correlation (R= -0.444) between CM level and CM to DST (Dural Sac termination) distance. Present study showed statistically significant (p=0.007) negative correlation (-0.244) between CM level and height. Significant difference in mean CM to DST distance was seen between male and female patients (p=0.000). No significant association was observed between CM to DST distance and age groups (0.238). Statistically significant (p=0.000) positive correlation (0.460) was observed between CM to DST distance and height   Conclusion: This study concluded that vertebral level of CM in adult Sri Lankan population varies from T12 middle to the L2-L3 disc space.  Key words – MRI, Conus Medullaris, Dural Sac Termination, T2 STIR