Objective To explore a new approach to determining the location of S1 screw for percutaneous screw fixation of the sacroiliac joint using a targeting device. Methods Virtual three-dimensional pelvic models were reconstructed using the computed tomography (CT) scan data obtained from 100 adult subjects without any bony abnormalities. Mimics software was used to determine the ideal operating plane for S1 sacroiliac screw fixation based on the osseous marks. The parameters for screw fixation on the plane were measured, including the entry point, the needle angle (γ) and the safety range, and the accuracy of these parameters was verified using the digital models. Results The ideal operating plane could be determined by the osseous prominences of ASIS (A) and PSIS (B) and the midpoint of S1 vertebral spines. The point at the posterior 1/3 of the line connecting points A and B could be defined as the entry point on the plane. The range of the needle angleγwas 101.4-117.2° for male and 109.5-120.78° for female patients, showing a significant sexual difference. Simulation results based on these parameters resulted in a total success rate of 91.25%(92.5%in male and 90%in female). Conclusion These parameters of the S1 screw can ensure a high success rate for percutaneous screw fixation of the sacroiliac joint and provide anatomical evidence for the development of a targeting device for the procedure.%目的：探讨一种新的第一骶椎（S1）骶髂螺钉定位方式，为导向器引导经皮骶髂螺钉固定的可行性提供应用解剖学基础。方法纳入100例正常成人骨盆CT原始数据，重建骨盆三维模型。利用Mimics软件中的相关功能寻找到以体表骨性标志定位的S1骶髂螺钉理想操作平面，继而逐步测量该平面上的置钉参数，包括进针点、进针角度γ及安全范围，最后利用数字模型检验新的置钉参数的准确性。结果（1）髂前后上棘骨性突出点（分别为A、B）与S1椎体棘突中点构成的平面可作为操作平面；（2） AB连线中后1/3交点可作为此平面上的有效进针点；（3）男性角γ范围：101.4°~117.2°，女性：109.5°~120.78°，左右无差异，性别间有差异；（4）按照新的参数置钉，80例半骨盆模型中置钉成功率统计：男性成功率：92.5%，女性成功率：90%。结论以A、B和S1椎体棘突中点定位操作平面，AB连线中后1/3交点为进针点，男性采取角γ=110°，女性采取γ=115°置钉满意，可作为新的螺钉定位方式及进一步研发经皮导向器设计的应用解剖学依据。
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