What is a Meniscus?

Tricia Christensen
Tricia Christensen

The meniscus is cartilage tissue that protects and helps promote flexibility in the human knees. The meniscus has a half moon shape, and there are two in each knee. In plural, the meniscus is referred to as menisci. Both are between the tibia, also called the shinbone, and the femur or thighbone.

A diagram of the knee, showing the lateral and medial menisci.
A diagram of the knee, showing the lateral and medial menisci.

Menisci are further classified by their location. The medial meniscus is on the inside of the knee, supporting the femur’s rounded edge in the inside of the thigh. The lateral meniscus is on the outside of the knee supporting the outside rounded part of the femur. The two act in concert as shock absorbers, so the weight of the femur does not smash into the smaller tibia. Both also are responsible for helping the knee to bend and flex without causing the bones to grind against each other.

A person wearing a meniscus brace.
A person wearing a meniscus brace.

The pressure of the femur causes each meniscus to look somewhat squashed. The curved part of the meniscus is toward the middle of the knee. The widest part of the meniscus sits at the outside of each side of the knee, as that is the area that needs the most cushioning. The inner part of each meniscus is made of liquid that helps lubricate the joints as they hinge and straighten.

There are two menisci in each knee.
There are two menisci in each knee.

Often when one refers to a knee cartilage injury, he or she is referring to a tear in the meniscus. In young adults, tears are most likely to be the result of traumatic injury during athletic games or practice. Suddenly twisting the knee can result in a small tear. Pain and swelling begins almost immediately, and a diagnosis of a torn meniscus is often confirmed with magnetic resonance imaging (MRI). Most tears are quite easily repairable with excellent outcomes after surgery.

After a meniscus tear, applying ice to the knee can help relieve pain and reduce swelling.
After a meniscus tear, applying ice to the knee can help relieve pain and reduce swelling.

Meniscus tears in older adults may be the cause of degeneration of the cartilage. As we age, the watery part of cartilaginous tissue tends to reduce. This type of injury caused by degenerative disease is sadly not reparable, though there may be some treatment, which can help reduce pain. Most doctors of Osteopathy recommend taking glucosamine once daily to increase and preserve joint health.

The best meniscus tear treatment depends on the severity of the injury.
The best meniscus tear treatment depends on the severity of the injury.
Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent wiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

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