Which major knee ligament is not classified as intra-articular?

The lateral collateral ligament (LCL) is classified as an extra-articular ligament, which means it is located outside the joint capsule of the knee. This distinguishes it from other major knee ligaments such as the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), and medial collateral ligament (MCL), all of which are intra-articular and lie within the knee joint itself. The distinction is significant because intra-articular ligaments are surrounded by synovial fluid and are subject to different types of injuries and healing processes compared to extra-articular ligaments. Understanding the anatomy and classification of these ligaments is crucial for diagnosing knee injuries and planning appropriate treatment strategies.