Meniscus: What to Know

Medically Reviewed by Poonam Sachdev on October 03, 2022
4 min read

The term meniscus comes from the Greek word for "crescent" because of its moon-like shape. This band forms a concave support pad for the thigh bone to rest on. Without the meniscus, you wouldn't be able to move your leg much without causing severe stress to your knee. 

Let's take a closer look at the meniscus. What does the meniscus do? Where is the meniscus located? What are some signs of damage and conditions affecting your meniscus? 

We'll also look at ways to prevent meniscus damage so you can keep yours healthy and strong.

The meniscus is a crescent-shaped piece of soft, rubbery fibrocartilage that provides shock protection for your knee. In addition, it provides a cushion between your tibia and femur. 

The meniscus safeguards the hyaline cartilage that lines the knee joint. Each knee joint has two wedge-shaped pieces of soft cartilage that make up the meniscus. They are collectively called menisci or the meniscus. The medial meniscus rests on the inside part of your knee. The lateral meniscus is set on the outside of the knee.

Some interesting facts about the meniscus:

  • The meniscus's extracellular matrix (ECM) in a healthy knee is composed of 72% water; the remaining 28% is composed of organic matter and cells. 75% of this organic matter is collagens.
  • Collagens (primarily, type 1 collagen) provide strength to the menisci. These large quantities of collagen set the meniscus apart from the hyaline or articular cartilage.
  • Only about 10 to 30% of the medial meniscus receives blood directly. The rest of the meniscus receives blood from diffusion, thanks to the synovial fluid. The lack of direct blood flow causes potential issues with healing, though, following a meniscus injury.

The lateral and medial meniscus are essential to your knee. They help while you are flexing or extending your leg.

The different meniscus functions in the knee joint include the following:

  • Load bearing
  • Shock absorption and protection
  • Joint lubrication
  • Joint stability
  • Weight distribution

The meniscus pads protect against osteoarthritis and hyaline cartilage degeneration. They allow the knee to bend and straighten without the femur and tibia rubbing together. The menisci also relieve weight-bearing stress on the knees. They provide support while compressing and distributing the load evenly within your knee.

When you put weight on a meniscus, it will compress and extend out to provide stability. "Hoop Stress" refers to the circular shape of circumference tension resulting from even distribution of weight load on the knee.

The menisci also help the femur and tibia flex and extend, so when you are walking, they lessen the resulting friction and protect the hyaline cartilage around the bones. As you move, the meniscus changes its shape to help with the movement of the knee.

Another function of the meniscus is to stabilize the knee joint.

The menisci are found on the medial and lateral sides of the knee. They are located inside and outside the knees, between the medial condyles of the tibia and femur bones. The menisci cover roughly 60% of the surface of the tibia. 

A transverse ligament connects the two menisci in the knee joint. The menisci attach to such parts of your leg tissues to help them stay in place when you move.

The medial meniscus connects to the knee at three points. This means it is less mobile than the lateral meniscus, which is attached at two points. As a result, the medial meniscus tears more frequently than the lateral meniscus.

When you first tear your meniscus, you may not feel any discomfort. However, you may notice pain or swelling in your knee. Stiffness in your knee joint is another sign of a meniscus tear.

The following are additional red flags:

  • A popping knee
  • Pain when you stand up
  • Your knee joint locking up
  • An inability to fully bend or stretch out your knee 
  • Limping

If you have any of these symptoms, don't ignore them. Consult a medical professional because a meniscus tear may not heal properly on its own.

Discoid meniscus is a congenital disability resulting in a meniscus that is thicker than usual and shaped like an oval instead of a crescent. Discoid meniscus often affects the lateral side of the knee. 

There are three types of a discoid meniscus, including:

  • Incomplete: The meniscus is thicker than average.
  • Complete: The meniscus covers the tibia entirely. 
  • Hypermobile Wrisberg: This occurs when the ligaments do not attach the meniscus to the femur and tibia.

Meniscus injury: You can tear your meniscus in three ways: vertically, horizontally, or radially. Such a tear in your meniscus will cause swelling and pain in your knee. Most often, you will need surgery to fix a serious meniscus injury. You are also more likely to develop arthritis following a meniscus tear.

If you want to try to strengthen your meniscus, you should exercise the muscles around it. The quadriceps on your lower thighs are a good place to start. Exercising these muscles will help strengthen your meniscus without harming your knee. 

Some other things you can do to help prevent your meniscus from tearing include:

  • Staying flexible
  • Stretching
  • Increasing range of motion
  • Exercising your hamstrings
  • Exercising your knee
  • Wearing proper shoes for different activities