目的　探讨儿童下颈椎椎弓根形态特征及其发育规律，为椎弓根螺钉内固定提供形态学依据。  方法     收集4～12岁儿童颈椎MSCT扫描资料60例，按每隔3岁为一年龄组，共分为3组，每组20例。将原始数据导入Mimics软件3D重建，在3D模型上测量C3~7椎弓根宽（PW）、椎弓根高（PH）、椎弓根骨通道全长（POCL）、外偏角（e角）及尾偏角（f角）并计算PW/PH（I值），按年龄组及节段行统计分析。  结果　PW、PH、POCL及e角总体随增龄呈递增趋势，10~12岁组各椎的PW、PH及POCL均与4~6岁组、7~9岁组有差异（P<0.05），e角和f角在不同年龄组间差异不大。在各组中不同椎序的PW均表现为逐增趋势。PH、POCL及 e角在各组中椎间差异不大。各组中椎间f角差异较大，由正值渐变为负值，C7的f角为负值中最大。I值总体随年龄增长呈递减趋势，不同年龄组间C3~7 的I值由>1.0渐变为<1.0；各组中椎间均无差异（P>0.05）。  结论    不同节段椎弓根形态特征发育规律性明显，但也存在个体差异性。4岁以上儿童下颈椎椎弓根形态上已具有置入椎弓根螺钉的可行性。

Objective　To explore morphological characteristic and developmental pattern of pedicles in lower cervical vertebrae in children for pedicle screw fixation.　Methods　MSCT data of cervical vertebrae were collected from 60 healthy children aged 4～12 years old. Children with an interval of three years were included in one group. There 20 children in each group. . The data were imported into Mimics for 3D image reconstruction the pedicle width (PW), pedicle height (PH), the entire of pedicle osseous channel (POCL), External deflection angle( e angle) and tail deflection angle (f angle) of C3~C7 were measured  and he PW / PH (I value) were calculated. Statistical analysis was performed by age group and segment.　Results　PW, PH, POCL and e angle generally showed an increasing trend with increasing age. PW, PH and POCL of each vertebra in 10~12 years old group had differences with 6~9 years old group and 4~6 years old group (P＜0.05), e and f angle had little difference between the different age groups. PW in each group showed a gradually increasing trend. PH, POCL and e angle had little difference between different vertebrae in each group. f angle had significant differences in each group, showing a gradient from a positive value to a negative values f angle of C7 was the maximally negative in value. I value generally showed decreasing trend with increasing age. I value of C3~C7 changed from ＞1.0 to ＜1.0 in different groups; it had no difference between different vertebrae in each group (P＞0.05).　Conclusion　The developmental pattern in pedicles of different segment is obvious, but there are individual differences. According to the cervical pedicle morphology, pedicle-screw technique in lower cervical pedicle of larger than 4 years old children is feasible.