Picture of Torn Meniscus

The knee is a joint where the bone of the thigh (femur) meets the shinbone of the leg (tibia). The knee is the largest joint in the body. It acts like a hinge, allowing the knee to flex (bend) and extend (straighten). There are four ligaments of the joint (the medial and lateral collateral ligaments and the anterior and posterior cruciate ligaments) that provide stability and steady the knee movement.

Cartilage within the joint provides cushioning to protect the bones from the regular trauma of walking, running, and climbing. Articular cartilage lines the joint surfaces of the bones in the knee (tibia, femur, and patella, or kneecap). The medial and lateral meniscus are two thicker wedge-shaped pads of cartilage attached to the leg bone (tibia). Each meniscus is curved in a C-shape, with the front part of the cartilage called the anterior horn and the back part called the posterior horn.

If the meniscus is damaged, irritation occurs with each flexion or extension of the knee. Damage to the meniscus may occur due to a twisting or over-flexing injury. Meniscal cartilage can also deteriorate or wear out because of age and overuse.

A tear of, or rent in, the cartilage in the knee is called a torn meniscus. Tears are described by how they look and where they are located. This information is usually found during a diagnostic procedure, like an MRI or knee arthroscopy. Common meniscus tears are described according to how they look, including longitudinal, bucket handle, parrot beak, and transverse.