A ligament is a band of tissue that connects a bone to another bone. The collateral ligaments of the knee are located on the outside part of your knee joint. They help connect the bones of your upper and lower leg, around your knee joint.

• The lateral collateral ligament (LCL) runs on the outer side of your knee.
• The medial collateral ligament (MCL) runs along the inside of your knee.

A collateral ligament injury occurs when the ligaments are stretched or torn. A partial tear occurs when only part of the ligament is torn. A complete tear occurs when the entire ligament is torn into two pieces.

Often, a cruciate ligament injury does not cause pain. Instead, the person may hear a popping sound as the injury occurs, followed by the leg buckling when trying to stand on it, and swelling. However, each individual may experience symptoms differently.

Learn more about Media and Lateral Collateral Ligament Injuries through our educational images: