Radiological evaluation of patellofemoral instability and possible causes of assessment errors

Figure 6 Measurement. A: Patellar tilt (a: The line joining the posterior femoral condyles; b: The transverse patellar axis); B: Lateral trochlear inclination (a: The line tangent to the posterior edge of the femoral condyles; b: The line drawn tangent to the lateral facet); C: Trochlear angle (a: the angle between the line passing posteriorly to both femoral condyles; b: The line joining the foremost parts of the medial and lateral facets); D: Trochlear depth in axial magnetic resonance imaging (a: The maximal anterior-posterior diameter of the medial femoral condyle; b: The maximal anterior-posterior diameter of the lateral condyle; c: The minimum distance of the deepest point of the trochlea).