Coronal oblique proton density-weighted scan showing various measurements of the notch width. All widths were measured in the same orientation as the reference line (RL). BW, bicondylar width; NW_AA, notch width at the anterior attachment of the anterior cruciate ligament (ACL); NW_I, notch width at the inlet; NW_MA, notch width at the midattachment point of the ACL; NW_O, notch width at the outlet.