Table 1 Lumbar finite element model: unit type and material properties
Structure | Unit Type | Thickness(mm) | Elastic Modulus(MPa) | Poisson’s ratio |
|---|---|---|---|---|
Vertebra cortical bone | S3R | 0.4 | 12,000 | 0.3 |
Vertebra cancellous bone | C3D4 | N/A | 100 | 0.2 |
Vertebra endplate cartilage | S3R | 0.25 | 1000 | 0.2 |
Vertebra posterior structure | C3D4 | N/A | 3500 | 0.25 |
Fibrous annulus(Normal) | C3D4 | N/A | 2.6 | 0.4 |
Nucleus pulposus(Normal) | C3D4 | N/A | 1.0 | 0.49 |
Fibrous annulus(Degenerative) | C3D4 | N/A | 12.3 | 0.35 |
Nucleus pulposus(Degenerative) | C3D4 | N/A | 1.7 | 0.4 |