Table 1

Summary of element type and material properties used in FEM

Component	Element type	Thickness or cross-sectional area	Young modulus (MPa)/Stiffness Parameter	Poisson ratio
Cortical bone³¹	Shell	0.4 mm	12,000	0.3
Vertebral endplate³²	Shell	0.25 mm	1,000	0.2
Cancellous bone²⁹ ^{, 30}	Tet	N/A	4,730ρ^1.56/1,987ρ^1.56/1,357ρ^1.56	0.2
Posterior elements³³	Tet	N/A	3,500	0.25
Annulus fibrosus ground substance³⁴	Hex	N/A	1.36	0.45
Annulus fibrosus collagen fibers³⁵	Fabric	N/A	Stress-strain curve
Nucleus pulposus³¹	Hex	N/A	K 1,666.7	Incompressible
Ligaments^{36, 37}	Spring	N/A	Hyperelastic	N/A
Cartilage endplate³⁸	8-Noded hex	N/A	24	0.4