目的　探讨对髌股关节切线位摄影的新技术。方法　在 6 2例病人膝关节侧位平片上测量了膝关节屈曲角 ,髌骨后缘线与股骨长轴、胫骨长轴及胫骨前皮肤线之间的夹角。分析其间的相互关系 ,得出髌骨后缘线和股骨之间夹角与膝关节屈曲角成直线相关关系 ,其直线方程为 :^y =2 +0 8x。髌骨后缘线与胫骨长轴及胫骨前皮肤线之间的夹角的平均值分别为 3 3°和 12 7°。根据测量结果研制出辅助摄影台 ,提出了用仰卧位屈膝 30°上下投照的新方法。结果　应用此方法成功地摄取了 40例病人的 5 8个髌股关节 ,此 5 8个髌股关节切线位X线片的显示情况按优、良、中、差四级评判 ,其中优 18个 (占 31% ) ,良 30个 (占 5 2 % ) ,中 8个 (占 14% ) ,差 2个 (占 3% )。优良率达 83%。造成照片质量差的原因是由于髌韧带过短而导致髌胫前角过小或成负角 ,髌股关节切线位摄影困难。结论　此新的摄影位置具有准确、舒适、简便易行及稳定的特点 ,可作为髌股关节疾病检查的常规位置推广应用 Objective To explore the new technique of tangent position photography of patellofemoral joint. Methods The flexion angle of knee joint, the angle between the posterior edge of patella and the long axis of femur, the long axis of tibia and the anterior tibial line were measured on the knee plain films of 62 patients. The relationship between the patella posterior margin and the femur was linearly related to the knee flexion angle. The linear equation was: ^ y = 2 +0 8x. The average value of the included angle between the posterior margin of the patella and the long axis of the tibia and the anterior tibial skin was 33 and 12 7, respectively. According to the results of the development of ancillary imaging stage, put forward the use of supine knee bent 30 ° up and down the new method of projection. Results Fifty-eight patellofemoral joints of 40 patients were successfully inoculated by this method. According to excellent, good, moderate and poor grades, the radiographs of the 5 8 patellofemoral joint tangential radiographs were excellent. Among them, 18 (31%), good 30 (52%), middle 8 (14%) and poor 2 (3%). Excellent rate of 83%. Caused by poor quality photos due to patellar ligament is too short and leads to anterior patellofemoral angle is too small or negative angle, patellofemoral joint tangent position photography difficult. Conclusion This new photographic location is accurate, comfortable, easy and stable, and can be used as a general location for patellofemoral joint disease examination