Meniscus tear. Coloured CT (computed tomography) scan of a meniscus tear (purple line on border of blue region, to the right of small yellow dot, lower right) in a knee joint. The thigh bone (femur, yellow, upper right) and shin bone (tibia) articulate at the knee joint. Here, two cartilage discs, or menisci, lie between the surfaces of the bones, providing a smooth surface for movement. A tear can occur for a number of reasons, including violent trauma, degeneration of tissue with age, or prolonged physical activity. The injury is particularly common in athletes. Most tears heal with rest, anti-inflammatory drugs and physical therapy.