menisci

Menisci (singular: meniscus) are crescent-shaped fibrocartilaginous structures located between the femur and tibia in the knee joint. In humans, the knee contains two menisci: the medial meniscus on the inner side and the lateral meniscus on the outer side. Each is wedge-shaped in cross-section, with a thicker outer rim and a thinner inner edge. Both are anchored to the tibial plateau and joint capsule by ligaments, and the anterior and posterior horns connect to surrounding structures to help stabilize movement.

The primary functions of the menisci are to distribute axial load across the articular surfaces, absorb shock, enhance joint stability and lubrication, and guide knee motion. By increasing the contact area between the femur and tibia, they reduce peak stresses and help maintain joint congruence during flexion, extension, and rotation. The outer third of each meniscus has a relatively better blood supply, while the inner portion is largely avascular, a factor that influences healing potential.

Clinically, meniscal injuries are common in athletes and can occur with twisting or trauma (or degeneratively in older adults). Symptoms include pain along the joint line, swelling, catching or locking, and reduced motion. Diagnosis is via physical examination and magnetic resonance imaging. Treatment ranges from conservative management with rest, physical therapy, and activity modification to surgical repair or partial meniscectomy. Complete removal of meniscal tissue is rare today and tissue preservation is emphasized to maintain function and reduce long-term risk of osteoarthritis.