A meniscus is a piece of cartilage (rubbery tissue) that acts as a shock absorber between bones and stabilizes the joints by evenly distributing the load across the joint area. Menisci (plural of meniscus) protect and cushion the joint surface and bone ends.
In the knee, the crescent-shaped menisci are positioned between the ends of the upper (femur) and lower (tibia) leg bones. The menisci protect the knee joint surface and absorb the shock produced by activities such as walking, running, and jumping.
WebMD Medical Reference from Healthwise