Abstract: Objective 　To obtain the basic parameters of sagittal curvature of subaxial cervical spine in normal population and analyze its clinical significance.　Methods　150 healthy volunteers who underwent standing neutral cervical spine lateral X-ray in our hospital were selected and divided into different groups according to age and gender. The data of cervical spinal angle (CSA) ,T1-Slope (TS) and C2~7sagittal Vertical Axis (C2~7 SVA）were measured and recorded.　Results　The CSA, TS and C2~7 SVA values of 150 healthy subjects were (20.28±6.86)°, (25.81±5.54)° , (15.74±5.96) mm, respectively. The independent sample T-test showed that there were significant differences in CSA and TS between male and female groups (P<0.05), and there was no significant difference in C2~7 SVA (P>0.05). One-way ANOVA showed that the values of CSA, TS, C2~7 SVA increased gradually with the increasing of age and the differences of TS, C2~C7 SVA in different age groups were statistically significant (P<0.05). The differences of CSA in different age in female group were statistically significant (P<0.05), but there was no statistical significance in male group (P>0.05). Person correlation analysis showed that TS was positively correlated with CSA and C2~7 SVA (r= 0.592, P<0.01; r= 0.308, P<0.01).　Conclusions　There are differences in CSA and TS between different genders. CSA, TS, C2~7 SVA show an increasing trend with the increasing of age. The values of CSA, TS,  C2~7  SVA in normal population and TS are positively correlate with CSA and C2~7 SVA, which can provide reference for the fixation of sagittal curvature of subaxial cervical spine during cervical surgery.

Key words: Normal population；　Cervical spinal angle；　T1-slope；　Distance of the C2~7 sagittal vertical axis