Posterior cruciate ligament–true statement is:
**Core Concept**
The posterior cruciate ligament (PCL) is a crucial ligament in the knee joint that plays a vital role in maintaining knee stability. It is one of the four major ligaments that connect the femur (thigh bone) and tibia (shin bone) in the knee joint.
**Why the Correct Answer is Right**
The PCL prevents excessive posterior translation of the tibia in relation to the femur, thereby maintaining knee stability. It is most taut during knee flexion and is composed of two bundles: the anteroinferior bundle and the posterousuperior bundle. These bundles provide different mechanical functions and are responsible for the PCL's proprioceptive and stabilizing properties.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the PCL is not the most taut during knee extension.
**Option B:** This option is incorrect because the PCL is not the primary stabilizer of the knee during varus and valgus stress.
**Option C:** This option is incorrect because the PCL is not the primary stabilizer of the knee during rotational stress.
**Clinical Pearl / High-Yield Fact**
The PCL is often injured in combination with other knee ligaments, particularly in high-energy trauma such as motor vehicle accidents or falls from a height.
**Correct Answer:** C.