What is a meniscus? There are actually two menisci in each knee that distribute the weight of the body and reduce friction in the knee. The menisci sit in the knee joint between the femur and the tibia along with cartilage, a smooth, gliding layer that allows pain-free motion at the joint. The menisci are crescent-shaped fibrocartilage structures that protect the cartilage from damage and allow the joint to continue to move freely.