Representative T1-weighted MR anatomical image of the thigh, axial (left) and sagittal (right) views. The 12 muscles are: sartorius SAR, vastus medialis VM, vastus intermedius VI, vastus lateralis VL, rectus femoris RF, biceps femoris short head BFS, biceps femoris long head BFL, semitendinosus ST, gracilis GRA, semimembranosus SM, adductor longus AL, adductor magnus AM. Panel A: Manually segmented tissues and individual muscles. Panel B: results of automated segmentation of individual muscles.