The meniscus is a crescent-shaped fibrocartilage filling the joint space between the femur and tibia. There are two menisci in each knee joint, the medial and lateral menisci, which have a thicker peripheral portion attached to the edge of the tibial plateau and a thinner central portion, which is slightly concave on the upper portion touching the femoral condyle and flat on the lower portion touching the tibial condyle. The inner part of the meniscus has no blood supply, and its nutritional evaluation is mainly from synovial fluid. Only the marginal part connected with the tibial rim can get blood supply from the synovial membrane. Because of the poor blood supply to the meniscus, it has poor healing ability after rupture and usually needs to be partially or completely removed. The medial meniscus is relatively large and C-shaped, with two anterior and posterior corners, the anterior foot is narrow and the posterior corner is wide and thick, the anterior corner is attached to the anterior cruciate ligament attachment point in front of the intercondylar ridge, the posterior corner is attached to the posterior cruciate ligament stop in front of the posterior intercondylar ridge, there is no articular surface there, the central outer edge is connected to the deep fibers of the medial collateral ligament, so only the anterior half of the medial meniscus is slightly loose and has room for movement. The lateral meniscus is smaller and O-shaped, with the anterior horn attached to the lateral side of the anterior cruciate ligament stop and anterior to the intercondylar ridge, while the posterior horn is attached to the posterior side of the intercondylar ridge and anterior to the posterior cruciate ligament stop, with the outer edge attached to the tendon and not to the lateral collateral ligament, so the mobility of the lateral meniscus is greater than that of the medial meniscus.