[Anatomy of the knee joint and its clinical relevance]

The stability of the knee joint is ensured by dynamic and static structures. The most important medial structures are the medial collateral ligament, medial capsular ligament, posterior oblique ligament, semimembranous muscle, and the pes anserinus group. The main supportive structures on the lateral side include the iliotibial band, lateral collateral ligament, lateral capsular ligament, popliteal tendon, arcuate ligament, and the biceps muscle. The cruciate ligament pillar is the center of rotation. The classification of knee instability requires new orientation that places the main emphasis on the translation of the joint compartments and the description of the injured structures.