Fig. 4From: Effect of facet-joint degeneration on the in vivo motion of the lower lumbar spineThe range of primary rotations for different facet-joint degeneration categories at the L3–S1 levels during flexion-extension, left-right bending, and left-right twisting activities: a L3–L4; b L4–L5; c L5–S1. Asterisk and double asterisks represent statistical significance between group comparisons (p < 0.05, p < 0.01)Back to article page