Which ligament resists posterior displacement of the tibia at 30-90 degrees of flexion?

Which ligament resists posterior displacement of the tibia at 30-90 degrees of flexion?

• A. PCL
• B. ACL
• C. MCL
• D. LCL

Answer: (A)

The posterior cruciate ligament (PCL) is the structure that plays a critical role in resisting posterior displacement of the tibia, particularly when the knee is flexed at angles between 30 to 90 degrees. The PCL connects the posterior aspect of the tibia to the anterior aspect of the femur and is particularly engaged during activities that involve knee flexion, such as running or squatting. When the knee is bent, the PCL helps provide stability by preventing the tibia from moving too far backwards relative to the femur, which is essential during activities that involve weight-bearing or changes in direction. This ligament is crucial for maintaining the integrity of the knee joint, especially in high-contact sports where posterior tibial translation could lead to injury or instability. Other ligaments, such as the anterior cruciate ligament (ACL), medial collateral ligament (MCL), and lateral collateral ligament (LCL), serve different roles in knee stability and movement, but they do not primarily resist posterior displacement of the tibia in the same manner as the PCL does.

The posterior cruciate ligament (PCL) is the structure that plays a critical role in resisting posterior displacement of the tibia, particularly when the knee is flexed at angles between 30 to 90 degrees. The PCL connects the posterior aspect of the tibia to the anterior aspect of the femur and is particularly engaged during activities that involve knee flexion, such as running or squatting.

When the knee is bent, the PCL helps provide stability by preventing the tibia from moving too far backwards relative to the femur, which is essential during activities that involve weight-bearing or changes in direction. This ligament is crucial for maintaining the integrity of the knee joint, especially in high-contact sports where posterior tibial translation could lead to injury or instability.

Other ligaments, such as the anterior cruciate ligament (ACL), medial collateral ligament (MCL), and lateral collateral ligament (LCL), serve different roles in knee stability and movement, but they do not primarily resist posterior displacement of the tibia in the same manner as the PCL does.