Table 1.
Material properties of current FEA models.
| Young's modules (MPa) | Poisson ratio | Cross-sectional areas (mm2) | Element types | Element sizes (mm) | ||
|---|---|---|---|---|---|---|
| Cortical | 12000 | 0.3 | 2.0 | |||
| Cancellous | 100 | 0.2 | 3.5 | |||
| Posterior structures | 3500 | 0.25 | 2.8 | |||
| Endplates | 1000 | 0.4 | — | Tetrahedral | 0.8 | |
| Cartilages | 10 | 0.4 | 0.6 | |||
| Annulus | 4.2 | 0.1 | 1.3 | |||
| Nucleus | 1 | 0.499 | 1.8 | |||
| Capsules | 7.5 (a < 25%) | 33 (>25%) | 0.3 | 30 | — | |
| ALL | 8 (<12%) | 21 (>12%) | 0.3 | 60 | — | |
| PLL | 11 (<11%) | 22 (>11%) | 0.3 | 21 | — | |
| LF | 15 (<6.2%) | 19 (>6.2%) | 0.3 | 60 | Cable | — |
| ITL | 10 (<18%) | 59 (>18%) | 0.3 | 10 | — | |
| ISL | 10 (<14%) | 12 (>14%) | 0.3 | 40 | — | |
| SSL | 9 (<20%) | 16 (<20%) | 0.3 | 30 | — | |
ALL: anterior longitudinal ligament; PLL: posterior longitudinal ligament; LF: ligamentum flavum; ITL: intertransverse ligament; ISL: interspinous ligament; SSL: supraspinous ligament (SSL).