47-year-old woman with low grade chondral lesion at retro-patellar cartilage.Proton density weighted (repetition time, 2200 msec; echo time, 30 msec) coronal MR image of left knee. Medial margin of PCL is located lateral to line between inferomedial corner of medial femoral condyle and medial tibial spine (arrow). This case was classified as negative for interposition of PCL into medial compartment of knee joint. PCL = posterior cruciate ligament