<prompt> Insal-Salvati index is used forOlecranonPatellaTalusScaphoid  <response>: a-length of patellar ligament b-length of patella INSAL-SALVATI indexab Normal range is 0.8 -1.2 If ratio increases it suggests patella is at a higher level-PATELLA ALTA If ratio decreases it suggests patella is at a lower level -PATELLA BAHA ref:apleys 9th edition pg no.565 