Fig. 7From: Mild (not severe) disc degeneration is implicated in the progression of bilateral L5 spondylolysis to spondylolisthesisAverage values of posteroanterior (+) and anteroposterior (−) shear stresses in the annulus fibrosus of the L5-S1 disc at peak flexion (Fx) and extension (Ex) loads of 10 Nm. The mildly degenerate L5-lytic model experienced the greatest increase in average anteroposterior stress in Fx and average posteroanterior stress in Ex from the baseline INTACT stateBack to article page