[Ligaments of the knee].

The ligaments of the knee can be divided into four groups. Ventral reinforcements are the patellar retinaculae. The posteromedial complex stabilizes the valgus stress. It consists of the medial collateral ligament, the thickened posteromedial capsule and a branch of the tendon of the semimembranosus muscle as well as the oblique popliteal ligament. On the lateral side the posterolateral complex protects the knee against varus stress. Here the lateral collateral ligament, the tendon of the popliteus muscle and the so-called popliteofibular fibres work together. The cruciate ligaments control the contact between femoral condyles and tibial plateau during flexion-extension of the knee. They course between the two layers of the capsule, the membranous and the synovial layer.