The principle of magnetic resonance examination is simply based on the hydrogen ion concentration of the examined area, and the higher the hydrogen ion concentration, the higher the magnetic resonance will show a high brightness signal shadow. When a ligament is injured or torn, due to local hemorrhage and edema, coupled with inflammatory infiltration, there will be an increase in local fluid and a higher concentration of hydrogen ions, and the corresponding injury site will show a high-brightness signal shadow on MRI. Tears of ligaments behave differently on MRI depending on the degree of injury. If there is only a mild injury to the ligament, the ligament integrity is present on MRI and a high-intensity signal shadow will appear around the ligament. If there is a strain of the ligament, the ligament will show thickening and tortuosity on MRI, and a high-intensity signal shadow in the ligament will be found. If there is a complete rupture of the ligament, the magnetic resonance will show high brightness signal shadows of the ruptured ligament, diffuse swelling of the ligament, extensive high brightness signal shadows, and also high brightness signal shadows of the ruptured transverse ligament.