A B S T R A C TBackground: Thickened ligamentum flavum(LF) has been traditionally related to lumbar canal stenosis. Till date many studies has been done to evaluate thickened LF and its association with age, gender, disc degeneration, mean LF thickness, increment in LF thickness at lumbar levels and right-left asymmetry or side dominance. But many discrepancies were found. Present study aimed to study these associations in the central India population. Material and methods: 345 individuals of 20 to 70 years old, with complains of low back ache and/ or leg pain whose Magnetic Resonance Imaging (MRI)of lumbosacral spine was done , were studied retrospectively. LF thickness was measured on axial T1WI of MRI at L3-4,L4-5 and L5-S1 levels. Mean and standard deviations of the parameters and t tests were taken. Significant difference was set at P < 0.05. Results: LF thickness significantly increased with age at all females than males. Increment was larger at L4-5 than at L5 thickness was observed with type IV -V disc degeneration, but was not statistically significant (p>0.05). Mean LF thickness at L5-S1 level on i.e 4.56 mm followed by L4-5(right-4.36 ,left-3.70mm) and L3 2.86mm). Mean thickness at L5-S1level on left side was found to be less i.e 1.28mm. Significant asymmetry was found between LF thickness lumbar level and right sided dominance was found at each level. Conclusion: LF thickness is an age and gender dependent phenomenon. Right sided dominance is found at each lumbar level. LF thickness is increased at L5 levels.The ligamentum flavum originates from the anterior aspect of lamina and inserts on the lamina Ligamentum flavum appearance on sagittal MRI from midline to linear, low signal intensity band that attaches to the superior border of one spinous process and the inferior surface of the spinous process below it. On parasagittal scans, LF is seen as an inhomogenous triangle with broader base near the lamina and (fig 1a and b). On axial MR studies, shaped structure that covers the laminae and facet joint anteriorly. LF is similar to signal But the signal intensity can be variable on MR because ligamentum flavum undergoes age related degenerative changes or become infiltrated with fat. Rarely it may undergo ossification or calcification. The elasticity of LF decreases with age.As a consequence to hypertrophy of ligamentum flavum diameter of the spinal canal gets reduced posteriorly. This reduced diameter of the spinal canal may notably squeeze the dural sac and nerve roots resulting in symptoms and these symptoms are strangely without any herniated or disc protrusion.3 Whenever there is increase LF, a posterior protrusion of th two, they causes nerve root compression. Hypertrophy of the ligament can be unilateral or bilateral and results from either injury or scar tissue. Normal ligaments are composed of yellow elastic fibres and grossly ha elasticity. It appears that during injury rupture of some of the elastic fibres of the ligamentum flava occurs, causing them to expand. Eventually repair takes place an...