What Is the Lateral Meniscus?

It is a 2-month-tooth-shaped fibrocartilage located on the articular surfaces on the inside and outside of the tibial plateau. Its cross section is triangular, thick outside and thin inside, and slightly concave at the top to fit the femoral condyle, and the bottom is flat to connect with the tibial plateau. Such a structure makes the femoral condyle form a deep depression on the tibial plateau, thereby increasing the stability of the spherical femoral condyle and the tibial plateau.

Chinese name: Lateral meniscus
Foreign name: lateral meniscus

Category: medicine
Definition: 2 month tooth-shaped fibrocartilage
Location: Articular surfaces on the medial and lateral sides of the tibial plateau

Fiber bundles between the lateral angle of the lateral meniscus and the anterior cruciate ligament

Starting from the anterior horn of the lateral meniscus and continuing to the anterior lateral surface of the anterior cruciate ligament in 50 cases (50 cases), the fiber bundle has a small amount of fibers and is scattered.

Artery of lateral meniscus fiber bundle

The arteries of the fiber bundles between the anterior horn of the lateral meniscus and the anterior cruciate ligament are issued by the arteries of the anterior horn of the lateral meniscus and the arteries of the ACL These arteries are small (less than 0.1 mm in outer diameter) and are faintly visible to the naked eye.

Biomechanics of lateral meniscus in knee joint

Outer meniscus bearing

When not bearing weight, the tibia and femur are not in contact with each other, and they are entirely between the meniscus pads. When loading, about 70% of the load-bearing area is on the meniscus, which greatly reduces the stress on the tibial plateau, thereby protecting the cartilage. If the meniscus is removed, the peak pressure on the tibial plateau can rise twice and will cause cartilage degeneration. Under load, the meniscus receives axial stress. Because the anterior and posterior tibia ligaments of the meniscus limit the lateral swelling of the meniscus, the axial stress is converted to its internal hoop stress. If these two ligaments are broken, then Its weight-bearing capacity is completely lost. The cartilage degeneration caused by cutting the anterior and posterior tibia ligaments of the meniscus is similar to the cartilage degeneration caused by the total meniscectomy. It can be inferred that when the meniscus is transected, the load-bearing function of the meniscus is completely lost.

The size of the meniscus resection is proportional to the peak stress on the tibial plateau and proportional to the degeneration of the tibial plateau. This requires us to cut as little as possible when the meniscus is partially removed.

Lateral meniscus maintains knee coordination

The meniscus moves with the tibia, the medial meniscus shifts less than the lateral meniscus, and the meniscus can deform during knee flexion and extension to adapt to the anatomical shape of the knee joint. The coordination of the geometry of the knee joint is maintained, so that the movement of the knee joint is maintained.

Outer meniscus remains stable

Meniscectomy does not cause tibia advancement when the anterior cruciate ligament is intact, and it causes greater tibia advancement when the anterior cruciate ligament is broken.

Outer meniscus absorbs shocks

In some patients with knee pain, arthroscopic pathology did not reveal any abnormalities, and the symptoms were obvious. Later inspection revealed that the meniscus had a poor absorption function.

In addition, the meniscus also has functions such as lubricating joints. The meniscus can evenly apply joint fluid to the joint surface, which greatly reduces the friction coefficient of the joint.