Table 3 Element type and material attributes of normal lumbar finite element model

Cortical bone

6 node points triangular facet shell element

12,000/0.3

1.2 mm

Cancellous bone

10 node points tetrahedron solid element

100/0.3

Lamina terminalis

10 node points tetrahedron solid element

4000/0.4

0.5 mm

Groundmass of annulus fibrosus

10 node points tetrahedron solid element

4.2/0.45

Nucleus pulposus

10 node points tetrahedron solid element

4/0.49

Fiber of annulus fibrosus

2 node points cord element

–

Articular cartilage

10 node points tetrahedron solid element

1000/0.3

0.5 mm

Contact face of superior articular process

6 node points triangular facet object element

Contact face of inferior articular process

6 node points triangular facet shell element

Anterior longitudinal ligament

2 node points cord element

75.9 mm²

Posterior longitudinal ligament

2 node points cord element

51.8 mm²

Ligamentum flavum

2 node points cord element

78.7 mm²

Capsular ligament

2 node points cord element

102.5 mm²

Interspinous ligament

2 node points cord element

36.3 mm²

Supraspinous ligament

2 node points cord element

75.7 mm²

Intertransverse ligament

2 node points cord element

40.5 mm²