Abstract: Objective To evaluate the MR findings of normal and abnormal collateral ligament and the meaning of medical jurisprudence appraisal.Methods The MR findings of12normal and13surgically confirmed injured collateral ligaments were retrospectively reviewed and compared.Results The normal tibial and fibular collateral ligaments were hypointense string on both T 1 and T 2 coronal MR images,with average length of6.8cm for tibial collateral ligament and5.7cm for fibular collateral ligament.13collateral ligaments were injured,including6tibial and3fibular collateral ligaments.Two cases(4ligaments)had both tibial and fibularcollateral ligaments injuries.The injury of collateral ligament was classified as:Grade I(5ligaments),Grade II(5ligaments),and Grade III(3ligaments).The complications of anterior cruci - ate ligament sprains(3cases),posterior cruciate ligament sprains(4cases),meniscal tear(2cases)were found in7patients(63.6%).Conclusion Coronal MR imaging can clearly demonstrate the structure of the knee collateral ligaments,accurately diagnose and classify the ligament injury,and correctly detect the compli - cations,MRI is very valuable for medical jurisprudence appraisal.

Key words: collateral ligament injury, magnetic resonance imaging, medical jurisprudence appraisal