What are the differences between medial and lateral menisci?

Structurally, the medial and lateral menisci differ in ways that influence how and why they get injured.

The medial meniscus, located on the inner side of the knee, is more C-shaped and firmly attached to the tibia, joint capsule, and medial collateral ligament (MCL). This rigid attachment makes it less mobile and, therefore, more susceptible to tearing. It bears up to 50% of the load on the inner compartment of the knee, and is more commonly affected than the lateral meniscus.

In contrast, the lateral meniscus, located on the outer side of the knee, is more circular (O-shaped) and has greater mobility. It covers a larger area of the tibial cartilage and is not as firmly fixed to the surrounding structures, allowing it to move back and forth during knee flexion (bending) and extension (straightening). This mobility helps it accommodate the rotational forces of the knee, but it is not immune to injury. It handles approximately 70% of the load on the outer compartment. Lateral meniscus tears often occur alongside ligament injuries, such as an ACL rupture, but they are also more likely to heal due to a better blood supply.