Fig. 5From: Mild (not severe) disc degeneration is implicated in the progression of bilateral L5 spondylolysis to spondylolisthesisAverage values of compressive (−) and tensile (−) stresses in the annulus fibrosus of the L5-S1 disc at peak flexion (Fx) and extension (Ex) loads of 10 Nm. Regardless of the bending load and model type, the annulus fibrosus experienced a significantly higher average compressive stress compared with the average tensile stressBack to article page