Menisci

We call meniscus a half moon or rarely disc-shaped intercartilage of collagenfibres, which occurs in a large number of jointss of the body, e.g. in the knee joint.

The task of the meniscus is to improve the guidance and contact of the joint surfaces (articular cartilage), for example from thigh to lower leg, it also contributes through its height to the tightening of the ligaments and thus to the improvement of lateral ligament strength and buffers the joint surfaces against impacts.

https://de.wikipedia.org/wiki/Meniskus_(Anatomy) _{(Wikipedia CC-by-sa-3.0)}