OBJECTIVE  The objectives of this study were to record the values of Insall-Salvati (IS) index and its modification in dogs classified into four different body weight groups and to determine whether these index values were influenced by sex. STUDY DESIGN  Bilateral mediolateral radiographs of 86 dogs were obtained. The dogs were classified into four different body weight groups: small, medium, large and giant. The patellar length (PL), caudal and cranial patellar ligament lengths (LLca and LLcr), stifle angle and superimposition of the femoral condyles were measured on the radiographs. The IS index and its modification (LLcr:PL) were calculated by dividing LLca or LLcr by the PL respectively. Spearman's correlation test and analysis of variance were used for statistical analyses. RESULTS  The sex of the dog and the presence of enthesophytes at the apex of the patella were two influential factors for the IS and LLcr:PL values. The mean IS values were 1.60 ± 0.28 in small dogs, 1.73 ± 0.27 in medium dogs, 1.82 ± 0.21 in large dogs and 1.97 ± 0.13 in giant dogs. The mean LLcr:PL for the same groups were 2.05 ± 0.23, 2.13 ± 0.19, 2.23 ± 0.21 and 2.27 ± 0.16 respectively. CONCLUSION  The reference intervals for the IS index were 1.04 to 2.16 in the small dogs, 1.19 to 2.27 in the medium dogs, 1.40 to 2.24 in the large dogs and 1.71 to 2.23 in the giant dogs. The reference intervals for the LLcr:PL index were 1.59 to 2.51 in the small dogs, 1.75 to 2.51 in the medium dogs, 1.81 to 2.65 in the large dogs and 1.95 to 2.59 in the giant dogs. Dogs with values exceeding these reference intervals have patella alta and those with values below these intervals have patella baja.

中文翻译：

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四种不同体重组的正常犬Insall-Salvati指数及其变化的比较。

目的本研究的目的是记录Insall-Salvati（IS）指数的值及其在分为四个不同体重组的狗中的变化，并确定这些指数值是否受性别影响。研究设计获得了86只狗的双侧中外侧X光片。将狗分为四个不同的体重组：小，中，大和巨型。在X光片上测量骨长度（PL），c骨和颅骨pa韧带长度（LLca和LLcr），st骨角和股骨con的重叠。通过分别用LLca或LLcr除以PL来计算IS指数及其修改（LLcr：PL）。使用Spearman相关检验和方差分析进行统计分析。结果狗的性别和the骨顶点处的肠胃菌的存在是影响IS和LLcr：PL值的两个因素。小型犬的平均IS值为1.60±0.28，中型犬为1.73±0.27，大型犬为1.82±0.21，巨型犬为1.97±0.13。同一组的平均LLcr：PL分别为2.05±0.23、2.13±0.19、2.23±0.21和2.27±0.16。结论小型犬的IS指数参考区间为1.04至2.16，中型犬为1.19至2.27，大型犬为1.40至2.24，大型犬为1.71至2.23。LLcr：PL指数的参考区间在小型犬中为1.59至2.51，在中型犬中为1.75至2.51，在大型犬中为1.81至2.65，在大型犬中为1.95至2.59。