Meniscus (anatomy)

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Overview
In anatomy, a meniscus is a moon-shaped figure. It usually refers to either of two specific parts of cartilage of the knee. The knee contains a lateral meniscus and a medial meniscus. Both are cartilaginous tissues that provide structural integrity to the knee when it undergoes tension and torsion. The menisci are also known as 'semi-lunar' cartilages - referring to their half-moon "C" shape - a term which has been largely dropped by the medical profession, but which led to the menisci being called knee 'cartilages' by the lay public.

Although menisci are largely associated with the knee, they are similar in function to structures called articular disks in other parts of the body.

Anatomy
The menisci are two pads of cartilaginous tissue which serve to disperse friction in the knee joint between the lower leg (tibia) and the thigh (femur). They are shaped concave on the top and flat on the bottom, articulating the tibia. They are attached to the small depressions (fossae) between the condyles of the tibia (intercondyloid fossa), and towards the center they are unattached and their shape narrows to a thin shelf.

Function
The menisci act to disperse the weight of the body and reduce friction during movement. Since the condyles of the femur and tibia meet at one point (which changes during flexion and extension), the menisci spread the load of the body's weight. This differs from sesamoid bones, which are made of osseous tissue and whose function primarily is to protect the nearby tendon and to increase its mechanical effect.

Injury


In sports and orthopedics, people will sometimes speak of "torn cartilage" and actually be referring to an injury to one of the menisci.

The Unhappy Triad is a set of commonly co-occurring knee injuries which includes injury to the medial meniscus.