Anterior Cruciate Ligament: Connects the anterior aspect of the intercondylar eminence of the tibia; runs superiorly, laterally, and posteriorly to attach to the medial aspect of the lateral femoral condyle. This ligament protects against anterior displacement of the tibia on the femur, and conversely, posterior displacement of the femur on the tibia. It also tightens on knee extension limiting hyperextension, and also extreme knee flexion. Provides rotary stability.
Posterior Cruciate Ligament: Connects the posterior aspect of the intercondylar fossa of the tibia; runs superiorly, medially, and anteriorly to attach to the anterolateral aspect of the medial condyle of the femur. This ligament protects against posterior displacement of the tibia on the femur, and conversely, anterior displacement of the femur on the tibia. It also tightens on knee flexion. Provides rotary stability.
Oblique Popliteal Ligament: Attaches posteriorly from the lateral femoral condyle to the distal tendon of the semitendinosus muscle. Reinforces the posterior knee joint capsule and resists full knee extension.
Medial Meniscus (C shaped): Located on top of the medial tibial plateau. Has attachments to the MCL and capsule. Because of this, its movement is restricted and is more susceptible to injury.
Lateral Meniscus (circular shaped): Located on top of the lateral tibial plateau. Has attachments to the arcuate popliteal ligament and popliteus muscle. Able to move more than medial meniscus and is less susceptible to injury.
Both menisci are thicker on their periphery compared to the internal edge of the meniscus and as such serve to deepen the joint to enhance stability, congruency, and to absorb shock. They carry 70% of the weight bearing load on the tibia. Only the outer 1/3 has vascularization and therefore is very poor at healing.
The open ends are named “horns” and are secured to the tibia via horn ligaments. Coronary ligaments attach the periphery of the menisci to the tibial condyles. The Transverse ligament attaches the anterior horns of the two menisci to each other.
The menisci are somewhat mobile with the greatest mobility occurring in the lateral meniscus. They move posteriorly during flexion and anterior during extension. They tend to follow the femoral condyles during rotation.