Fig. 1
From: Local torsion of distal femur is a risk factor for patellar dislocation
Three lines were drawn to evaluate the femoral torsion in CT images. The first line passes through the center of the femoral head and neck. (FNA, a). The second line is the tangent line to the gastrocnemius muscle in the posterior compartment of the leg (DFL, b). The third line is the tangent line to the posterior condyles (PCL, c). The angle between FNA and PCL (femoral anteversion)and the angle between DFL and PCL (distal femoral torsion) were measured.