Table 2 Element type and material attributes of DS finite element model

Cortical bone

6 node points triangular facet shell element

8000/0.3

1.2 mm

Cancellous bone

10 node points tetrahedron solid element

34/0.3

Lamina terminalis

10 node points tetrahedron solid element

4000/0.4

0.5 mm

Groundmass of annulus fibrosus

10 node points tetrahedron solid element

16/0.4

Nucleus pulposus

10 node points tetrahedron solid element

8/0.45

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

Ligament umflavum

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