Fig. 3From: Patellar instability: the reliability of magnetic resonance imaging measurement parametersMeasurements for patellar height: a Insall–Salvati index (ISI) = C/A; b modified Insall–Salvati index (MISI) = E/B; c Caton–Deschamps index (CDI) = D/B; d Blackburne–Peel index (BPI) = F/B; and (e) patellar trochlear index (PTI) = G/BBack to article page