Up to 80% of the lateral tibial plateau articular cartilage is covered by the circular lateral meniscus.
Anteriorly, it is attached to the tibia behind the attachment of the ACL. Along its peripheral margin the lateral meniscus is loosely attached to the joint capsule by the coronary ligament. The absence of an attachment of the meniscus to the lateral collateral ligament (LCL) allows passage of the popliteal tendon between the lateral meniscus and LCL—the popliteal hia- tus. Behind the intercondylar eminence and anterior to the posterior horn of the medial meniscus the posterior horn of the lateral meniscus is attached to the tibia. In 50% of people, the posterior horn of the lateral me- niscus receives extra stability from the me- niscofemoral ligaments of Humphry and Wrisberg.
Knowledge of the meniscal attachments helps in understanding the differential mo- bility of the medial and lateral menisci. With knee flexion and extension, the menisci are able to slide relative to the articular surface of the tibial plateau. Through three- dimensional MRI, the less constrained lat- eral meniscus has been shown to have an average excursion of 11 mm, with the more extensively fixed medial meniscus averaging only 5 mm of excursion (Fig. 6).
The more limited range of motion of the medial menis- cus allows it to serve as an anterior stabilizer but also makes it more vulnerable to tearing and injury. In both menisci, the anterior horns are more mobile than the wider poste- rior horns, rendering the posterior horns more susceptible to injury.