Table 1

Material Properties of Components of the Spinal and Pelvic Finite Element Model.

ComponentElement FormulationYoung's Modulus(MPa)Poisson's Ratio
BonyStructure
Vertebral Cortical BoneIsotropic, elastic hexelements12,0000.3
Vertebral Cancellous BoneIsotropic, elastic hexelements1000.2
Posterior Cortical BoneIsotropic, elastic hexelements12,0000.3
Posterior Cancellous BoneIsotropic, elastic hexelements1000.2
Pelvic Cortical BoneIsotropic, elastic hexelements17,0000.3
Pelvic Cancellous BoneIsotropic, elastic hexelements100.2
Intervertebral Disc
Annulus (ground)Neo-Hookean, hexelementsC10 = 0.348, D1 = 0.3
Annulus (fiber)Rebar357-5000.3
Nucleus PulposusIncompressible fluid, cavity elements10.499
Ligaments
Anterior LongitudinalTension-only, Trusselements7.8(<12%),20.0(>12%)0.3
Posterior LongitudinalTension-only, Trusselements10.0(<11%),20.0(>11%)0.3
LigamentumFlavumTension-only, Trusselements15.0(<6.2%),19.5(>6.2%)0.3
IntertransverseTension-only, Trusselements10.0(<18%),58.7(>18%)0.3
InterspinousTension-only, Trusselements10.0(<14%),11.6(>14%)0.3
SupraspinousTension-only, Trusselements8.0(<20%),15.0(>20%)0.3
CapsularTension-only, Trusselements7.5(<25%),32.9(>25%)0.3
Anterior SITension-only, Trusselements125(<2.5%),175(>5%),325(>10%),316(>15%)0.3
Inner posteriorSITension-only, Trusselements43(<2.5%), 61(>5%),113(>10%),110(>15%)0.3
Outer posterior SITension-only, Trusselements150(<2.5%),211(>5%),391(>10%),381(>15%)0.3
IntraosseusTension-only, Trusselements40(<2.5%), 57(>5%),105(>10%),102(>15%)0.3
SacrospinousTension-only, Trusselements304(<2.5%),428(>5%),792(>10%),771(>15%)0.3
SacrotuberousTension-only, Trusselements326(<2.5%),458(>5%),848(>10%),826(>15%)0.3
Joint
ApophysealJointsNon-linear Soft contact, GAPPUNIelements--
Sacroiliac JointsSoft Contact with ExponentialBehavior--