Which ligament prevents varus stress to the knee?

• A. Anterior cruciate ligament
• B. Lateral collateral ligament
• C. Medial collateral ligament
• D. Meniscus

Answer: (B)

Varus stress on the knee is resisted mainly by the lateral collateral ligament. This ligament runs along the outer side of the knee and tightens when a force tends to push the knee outward or open the lateral side, preventing that varus (bowing) movement. The medial collateral ligament, in contrast, resists valgus stress (pushing the knee inward toward the midline). The anterior cruciate ligament mainly controls anterior translation and rotation of the tibia, while the meniscus provides cushioning and joint stability but is not the primary restraint to varus stress. So, the lateral collateral ligament is the best answer because its primary role is resisting varus forces.