What type of forces does the LCL stabilize against?

What type of forces does the LCL stabilize against?

• A. Valgus
• B. Posterior shear
• C. Varus
• D. Anterior shear

Answer: (C)

The key idea is that the lateral collateral ligament (LCL) resists varus stress at the knee. It runs on the outer side from the lateral femoral epicondyle to the head of the fibula, so when a force pushes the knee inward (toward the midline) or tries to open the lateral joint space, the LCL tightens to prevent that varus (bow-legged) collapse. It may also help limit external rotation of the tibia, especially with the knee near extension. It does not primarily resist valgus forces—that role belongs to the medial collateral ligament—and it is not the main restraint for anterior or posterior shear movements, which involve the ACL and PCL.

The key idea is that the lateral collateral ligament (LCL) resists varus stress at the knee. It runs on the outer side from the lateral femoral epicondyle to the head of the fibula, so when a force pushes the knee inward (toward the midline) or tries to open the lateral joint space, the LCL tightens to prevent that varus (bow-legged) collapse. It may also help limit external rotation of the tibia, especially with the knee near extension. It does not primarily resist valgus forces—that role belongs to the medial collateral ligament—and it is not the main restraint for anterior or posterior shear movements, which involve the ACL and PCL.