ABSTRACT
The knee is composed of several distinct articulations including medial and lateral tibiofemoral articulations as well as the patellofemoral articulation. Proper gliding and rolling in the knee are provided through a complex network of ligaments, fibrocartilagenous menisci, and capsular structures. The knee is surrounded by several large muscle groups that also play an important role in its dynamic stability. Anteriorly, the quadriceps inserts onto the patella which is then connected to the tibia through the patellar tendon. This series of muscles and tendons is called the extensor complex. The hamstring muscles run posteriorly from the ischium to the tibia (semi-membranosis, semi-tendinosis) and the fibula (biceps femoris). The major static stability is afforded the knee by the medial and lateral collateral ligaments and the anterior and posterior cruciate ligaments, which serve to restrain valgus and varus forces as well as anterior and posterior forces, respectively.
