The meniscus is a C-shaped piece of fibrocartilage which is located at the peripheral aspect of the joint. The majority of the meniscus has no blood supply. For that reason, when damaged, the meniscus is unable to undergo the normal healing process that occurs in most of the rest of the body. In addition, with age, the meniscus begins to deteriorate, often developing degenerative tears. Typically, when the meniscus is damaged, the torn piece begins to move in an abnormal fashion inside the joint.
The Meniscus : Shock Absorber for the Knee (OA Centers for Orthopaedi cs)
Torn cartilage (Meniscus) (The Center for Orthopaedics & Sports Medicine)