The lateral meniscus is a crescent-shaped piece of cartilage that sits on the outer side of the knee joint. Some other synonyms for this term include the outer meniscus, the outside meniscus, the lateral semilunar cartilage, and the fibrocartilage disc. These synonyms all refer to the same structure, which plays an important role in stabilizing the knee joint, cushioning the bones, and distributing weight and pressure across the joint. Injuries to this area can cause pain, swelling, and limited mobility, so it is important to seek medical attention if you experience these symptoms.