The meniscus is a cushion of cartilage that exists between the femur bone and the tibia bone that provides a shock absorbing function within the knee joint. There's typically two menisci one on the inside part of the knee as well as one on the outside part of the knee. One of the most common injuries to the meniscus is a meniscal tear where the shock absorbers or cushions of cartilage are torn. There are many different kinds of tears of meniscus depending on the mechanism of injury.