Medial (A) and Lateral (B) ligamentum flavum thickness variation by lumbar level.

<p>Comparison between asymptomatic and chronic low back pain subjects segregated by spinal level. Error bars span one standard deviation. Asterisks denote significant differences with * <i>p</i> < 0.05. In (A) the symptomatic medial thickness tended to be larger than in the normal (L1: p = 0.0839, and L2: p = 0.0652, respectively). All other comparisons did not reach significance.