Between the femur and tibia, sitting centrally in the knee joint, are two C-shaped pads (the medial and lateral menisci) that act as a cushion or shock absorber between the two bones.
The meniscal pads are made of cartilage. The meniscus has a poor blood supply except on the very periphery of the meniscus.
Peripheral tears, although rare, can be repaired, especially in the younger patients. With the inner portion of the meniscus having a poor blood supply, the meniscus has little healing potential, which leads many tears to surgery to help resolve the symptoms.
The meniscus is often injured with twisting the knee while in a squatting position. This creates a split or flap to occur while the meniscus is being compressed.