- The medial collateral ligament (MCL) provides stability to the inner (medial) aspect of the knee.
- The lateral collateral ligament (LCL) provides stability to the outer (lateral) aspect of the knee.
- The anterior cruciate ligament (ACL), in the center of the knee, limits rotation and the forward movement of the tibia.
- The posterior cruciate ligament (PCL), also in the center of the knee, limits backward movement of the tibia.
Other ligaments are part of the knee capsule, which is a protective, fiber-like structure that wraps around the knee joint. Inside the capsule, the joint is lined with a thin, soft tissue, called synovium.