The anatomical structures in posterolateral corner of the knee are complex and were classified to layers.The lateral compartment of the knee is stabilized by complex arrangement of ligaments, tendons and muscles, these guards against various angulations, rotation, and translation of the tibia.The Concept of posterolateral region of the knee was introduced as functional tenoligamentous structures.MRI interpretation would ensure better diagnosis and anatomical reconstruction. There are variable surgical techniques to treat posterolateral instability,so it is vital to know the appropriate anatomy of this region. This book which is based on a research study conducted on discussing anatomical and radiological ( MRI ) study of the posterolateral corner structures of knee. It will be valuable for anatomists, radiologists, and orthopaedic surgions and medical doctors interested in studying this region.