The knee is one of the most frequently injured joints because of its anatomic structure, its exposure to external forces, and the functional demands placed on it. Basic to an understanding of knee injuries is an understanding of the normal knee anatomy. Although much emphasis has been placed on the ligaments of the knee, without the supporting action of the associated muscles and tendons, the ligaments are not enough to maintain knee stability. The structures around the knee have been classified into three broad categories: osseous structures, extraarticular structures, and intraarticular structures.
