Objective The changes of microstructure in different areas of cervical articular process

C2 to C7 and left and right side of cervical spine in adults and their relationship with micro-finite element mechanical response of articular process was analyzed

to predict and evaluate the risk of cervical spondylosis such as cervical instability

osteoporosis and articular process fracture caused by the change of micromorphology and mechanical load of articular process. Methods Fresh upper and inferior processes of cervical vertebrae from 36 adults were scanned by Micro-CT.The (VOI) of the two regions of interest of the upper and inferior processes of the cervical vertebrae were selected manually and the microstructure parameters of the articular processes were calculated.The micro-finite element analysis of the cubes with the volume of 8 mm×8 mm×8 mm taken by ring drill was made

and the relationship between the microstructure and the mechanical parameters of the facet was analyzed and compared. Results The main effect analysis showed that there were statistically significant difference in the BV/TV

BS/BV

Tb.Sp parameters between the upper and lower articular processes（P＜0.05）

and the Tb.Th parameters were statistically significant between the left and right sides of the articular process（P＜0.05）.There were significant differences in BV/TV

Tb.N

BS/BV

Tb.Th

Tb.Sp

Tb.Pf parameters of articular process among different vertebrae sequences（P＜0.05）.The Tb.N parameters of interaction between different intervertebral sequences and upper and lower articular processes were statistically significant（P＜0.05）.The stress components in the six directions of the facet bone microfinite element model were σx

σy

σz

σxy

σxz

σyz.The stress components in the six directions of the facet microfinite element model were as follows:S11

S22

S33

S12

S13

S23.The axial stress value of S33 was the largest in the axial stress of σz

which accord with the direction of the loading of the joint process (along the direction of the Z axis)

and the stress of the twodimensional plane of S12 was the smallest

which indicated that the shear stress of the articular process of the cervical spine was less than the principal stress during movement. Conclusion The BV/TV

Tb.N parameters of C3 articular process are the largest.BV/TV

Tb.Th is positively correlated with the stress of articular process

negatively correlated with the degree of fracture

the degree of stress concentration and internal shear force.Therefore

the loading ability of C3 articular process is better

the risk of fracture and other injuries is relatively lower.BS/BV

Tb.Sp

Tb.Pf parameter value of C2 joint process are the largest

Tb.Pf

Tb.Sp are negatively correlated with stress

and positively correlated with fracture

osteoporosis

hyperplasia

degeneration and so on.It is suggested that the risk of cervical spine diseases such as fracture

osteoporosis

hyperplasia and degeneration of C2 joint process is higher than that of other joints.The cumulative result of plastic strain in the whole finite element model of facet bone is zero during the whole deformation process

that is to say

there is no plastic deformation nor yield under this load condition.It is shown that there is no fracture in the finite element model of facet bone under normal physiological load in adults.