成人寰椎后弓部分结构测量及意义

目的　获得成人寰椎后弓部分解剖参数，为后弓内固定钉板系统的设计提供依据。 方法　对60名成人（男30，女30）寰椎三维CT及40具干燥寰椎标本进行测量，测量指标有后结节中央及距中央5、10、15 mm处高度（矢状面垂直距离）及厚度（轴位垂直距离）、后弓水平面夹角、内侧面椎动脉沟半距、外侧面椎动脉沟半距，比较CT测量数据与标本测量数据有无差异。 结果　CT测量：后结节中央高度为（9.48±0.95）mm，厚度为（7.80±1.60）mm，后弓夹角为（130.70±12.31)°，内侧面椎动脉沟半距为（11.08±1.28）mm，外侧面椎动脉沟半距为（20.13±1.53）mm；标本测量：后结节中央高度为（9.97±2.18）mm，厚度为（7.44±1.32）mm，后弓夹角为（135.07±9.59）°，内侧面椎动脉沟半距为（11.33±0.52）mm，外侧面椎动脉沟半距为（20.86±0.84）mm。CT测得内、外侧面椎动脉沟半距均小于标本测得数据，且差异有统计学意义。 结论　CT资料可较好反映实体的解剖特征，解剖学测量可为临床实践提供有力参考。

Measurements of posterior arch of atlas and its significance

Objective　 To acquire partial anatomical parameters of posterior arch of atlas, and to provide a reference for design of screw-plate fixation system.　Methods　A total of 60 3D CT and 30 dry atlas specimens were used to measure anatomical data．The parameters included anterior-to-posterior thickness and superior-to-inferior height of the posterior ring of C1 at the midline as well as at 5mm, 10mm, 15mm lateral to the midline, angle of the posterior arch, the semi-distance of vertebral artery groove in inner surface and the semi-distance of vertebral artery groove in outer surface. The data gained from CTs and specimens was then compared.　Results　CTs measurement: The height of the center of posterior nodule was(9.48±0.95)mm, and the respective thickness was (7.80±1.60)mm. The angle of posterior arch was (130.70±12.31) °. The semi-distance of vertebral artery groove in inner surface and the semi-distance of vertebral artery groove in outer surface was (11.08±1.28) mm and (20.13±1.53) mm, respectively. Specimens measurement: The height and thickness of the midline was (9.97±2.18) mm and (7.44±1.32) mm, respectively. The angle of posterior arch was（135.07±9.59）°. The semi-distance of vertebral artery groove in inner and outer surface was（11.33±0.52）mm and（20.86±0.84） mm, respectively. The data of the semi-distance of vertebral artery groove gained from CTs was smaller than that measured from specimens with statistical difference.　Conclusion　Data measured from CT can present anatomical structure precisely and anatomical study is of referable significance in clinical practice.