The main functions of the meniscus include stabilizing the joint, absorbing shock, lubricating the joint, and assisting knee movement, as follows: First, stabilizing the joint: the special shape of the meniscus, which is thick on the outside and thin on the inside, concave on the top and flat on the bottom, can fill the joint space of the femur and tibia, making the joint more stable. Second, shock absorption: the meniscus is composed of fibrocartilage, which is rich in elasticity and can withstand gravity and absorb local shocks. Third, lubricate the joint: the meniscus can spread synovial fluid, lubricate the articular cartilage, and protect the articular cartilage. Fourth, assist knee joint activities: assist knee joint flexion and extension activities and rotation activities, the meniscus can move back and forth when the knee joint is straightened and flexed, and when the knee joint is rotated, the two menisci are one forward and one backward, so the meniscus is most likely to be damaged or even torn during the rotation activities. You should pay attention to protecting the meniscus of the knee joint, avoiding joint sprains and enhancing the strength and power of the muscles around the knee joint.