Which of the following is true about posterior cruciate ligament:
**Core Concept**
The posterior cruciate ligament (PCL) is a vital stabilizing ligament of the knee joint, connecting the femur and tibia. It plays a crucial role in preventing excessive posterior translation of the tibia relative to the femur.
**Why the Correct Answer is Right**
The PCL is composed of two bundles: the anteroinferior bundle and the posterousuperior bundle. The anteroinferior bundle is more taut in flexion and is responsible for preventing posterior tibial translation in this position. The PCL is also in close proximity to the popliteus tendon and the menisci, which can be involved in its injury. The mechanism of PCL injury often involves a posterior force on a flexed knee, such as in a dashboard injury during a car accident.
**Why Each Wrong Option is Incorrect**
**Option A:** The PCL is not the most commonly injured ligament in the knee. The anterior cruciate ligament (ACL) is more frequently injured.
**Option B:** The PCL is not responsible for preventing excessive anterior translation of the tibia. This is the role of the ACL.
**Option C:** The PCL is not a bony structure. It is a ligamentous structure connecting the femur and tibia.
**Clinical Pearl / High-Yield Fact**
The PCL is often injured in combination with other ligaments, such as the ACL and medial collateral ligament (MCL), in a knee injury known as the "trifecta" injury.
**Correct Answer:** C.