Chapter 108 focuses on knee MRI, first discussing some general technical considerations of musculoskeletal MRI, and then discussing individual components, including the menisci, cruciate and collateral ligaments and articular cartilage, which often contribute to knee pathology. After initial radiographic assessment, MRI is the most helpful imaging modality to detect internal derangement of the knee, and the knee is the most commonly ordered extremity MRI examination. MRI is an extremely powerful tool for determining the source of the patient’s symptoms and directing future treatment, and it is the most sensitive imaging study to evaluate the menisci, ligaments, tendons, and muscles in the setting of knee pain or instability. Additionally, MRI is also an excellent tool to evaluate the bones and articular cartilage.