The knee has two menisci, an inner or medial meniscus and an outer or lateral meniscus. These c-shaped "donuts" are made of cartilage and allow the bones (femur and tibia) to glide smoothly against one another during flexion (bending) and extension (straightening) of the knee.
These structures act as shock absorbers and will distribute weight-bearing load on the knee.
Meniscal knee injuries
are very common in athletes, especially in sports that require pivoting (tennis/squash), pounding (running), and turning (skiing). Degenerative changes due to the aging process can also affect the knee menisci.