中文摘要：

目的：为经口前路枢椎椎弓根螺钉固定系统的临床应用提供解剖学依据。方法：60具成年人枢椎干骨标本，观察并确定前路枢椎椎弓根螺钉的安全进钉点，测量其与枢椎上关节面、前正中矢状面及与横突孔内侧壁的距离，前路枢椎椎弓根螺钉的骨性钉道长度，安全的进钉方向（向外倾斜角度、向下倾斜角度）。结果：经口前路枢椎椎弓根螺钉的安全进钉点为：与枢椎上关节面的距离为（5．0±1．0）mm；与前正中矢状面的距离为（7．8±0．7）mm；与横突孔内侧壁的距离为（6．1±1．7）min。前路枢椎椎弓根的骨性钉道长度为（26．4±1．5）mm。安全置钉方向为向外倾斜（18±4）°，向下倾斜（14±4）°。结论：（1）经121前路枢椎椎弓根螺钉的最佳进钉点为：枢椎上关节面下5．0mm，距离前正中失状面7．8mm处；（2）安全进钉方向为：向外倾斜18°，向下倾斜14°，置入的枢椎椎弓根螺钉均位于骨性钉道内，安全可靠。

英文摘要：

Objective： To assess the feasibility ofpedicle screw fixation transoral approach to axis, based on the anatomical observation and measurement of axis. Methods： Sixty dry axis specimens were underwent anatomic measurement, including the distances from screw entrance point to superior articular process, to the sagittal midIine of spine, to medial edge of transverse foramen; the screw length in axial pedicle; the extraversion angle （α） and declination angle （β） of screw insertion. Results： The mean distance from screw entrance point to superior articular process was about （ 5.0± 1.0 ） mm, to the sagittal midline （7.8±0.7） mm, and to medial wall of transverse foramen （6.1± 1.7 ） mm. The averaged length of the pedicle was about （26.4± 1.5） mm,and the angle （α） was about （18±4）° ,angle （β） （14±4）°. Conclusions： （1） The best screw entrance point of the transoral approach is under the inferior edge of midline of axis about 7.8 mm. （2） For safe operating, keep right screw insertion. superior articular process of axis about 5.0mm, part from the angle （α） should be 18°, and angle （β） 14°, which will