Magnetic resonance imaging is the best test to evaluate ligament injuries. Conventional ligament injuries are graded into three levels.1. Level 1, is a mild injury. A mild ligament injury is one in which there is a slight elongation of the ligament and a change in morphology, but the signal within the ligament is normal, with no abnormal signals and edema in the soft tissue surrounding the ligament. 2. Grade 2 is a partial tear of the ligament. Grade 2 is a partial ligament strain, showing thickening and tortuosity of the ligament, partial fiber disruption, moderate signal on T1-weighted images, diffuse high signal on T2-weighted images, and diffuse swelling of the surrounding soft tissues. 3. Grade 3 is a complete ligament tear. A third-degree injury is a complete rupture of the ligament. It can be seen that the ligament is completely torn, the severed end can be separated, the severed end is cauda equina, the T2-weighted image shows a significant high signal, and the surrounding soft tissues show diffuse swelling. According to the site of ligament injury, the ligament injury is divided into avulsion fracture of the ligament attachment point and injury of the ligament.