The Insall-Salvati Ratio is the ratio of the length of the patellar tendon to the length of the patella, when measured on an X-ray or MRI with the knees bent to 30 degrees.


Normal Insall-Salvati ratio

The normal ratio is 0.75 - 1.50. Higher ratios suggest that the patella is abnormally high.


The patella - important anatomical relationships

The kneecap or patella is part of a chain of structures that help to straighten the knee.



Evaluation of patella alta using MRI measurements in adolescents. Yılmaz B, Ozdemir G, Sirin E, Cicek ED, Anıl, BS and Bulbun G. Indian J Radiol Imaging. 2017 Apr-Jun; 27(2): 181–186.

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