Table 1. Average Mechanical Parameters across all Discs.

In-plane strain calculated from displacement-encoded imaging (dualMRI) and relative shear moduli were averaged over the entire disc regions of interest in the indicated image planes. Strains were calculated with respect to the image plane (E_xx, E_yy, E_xy) as well as in in-plane principal directions (E₁, E₂). Maximum shear strain (γ_max) was also determined per pixel. Data represents mean ± standard deviation (n=3 biological replicates). Significant differences in a mechanical parameter estimated from compression vs. estimated from bending experiments are indicated in bolded p values.

Mechanical Parameter	Image Plane	Compression	Bending	Paired t Test (p)
Exx	Coronal	0.017 ± 0.003	0.010 ± 0.001	0.061
	Sagittal	0.023 ± 0.002	0.023 ± 0.004	0.835
E yy	Coronal	−0.035 ± 0.005	−0.034 ± 0.008	0.924
	Sagittal	−0.026 ± 0.005	−0.0311 ± 0.006	0.189
Exy	Coronal	0.001 ± 0.002	0.001 ± 0.002	0.505
	Sagittal	0.003 ± 0.001	0.002 ± 0.001	0.039
E 1	Coronal	0.017 ± 0.007	−0.001 ± 0.005	0.029
	Sagittal	0.029 ± 0.005	0.022 ± 0.004	0.127
E 2	Coronal	−0.051 ± 0.004	−0.048 ± 0.005	0.700
	Sagittal	−0.035 ± 0.010	−0.037 ± 0.008	0.814
γ max	Coronal	0.034 ± 0.002	0.024 ± 0.003	0.013
	Sagittal	0.031 ± 0.004	0.030 ± 0.006	0.923
Relative shear modulus	Coronal	18.3 ± 5.8	38.9 ± 16.8	0.031
	Sagittal	8.4 ± 1.6	50.4 ± 13.0	0.133