**Core Concept**
The posterior gliding of the tibia on the femur is a normal movement that occurs during knee flexion. However, excessive posterior movement can lead to instability and compromise the function of the knee joint. The mechanism that prevents this excessive movement involves the static and dynamic stabilizers of the knee.

**Why the Correct Answer is Right**
The primary mechanism that prevents posterior gliding of the tibia on the femur is the medial and lateral collateral ligaments, particularly the medial collateral ligament. The medial collateral ligament provides a strong attachment between the femur and the tibia, preventing excessive posterior movement during knee flexion. Additionally, the posterior cruciate ligament (PCL) and the popliteus muscle also contribute to the stability of the knee joint.

**Why Each Wrong Option is Incorrect**
**Option A:** The anterior cruciate ligament (ACL) is primarily responsible for preventing excessive anterior movement of the tibia on the femur, not posterior gliding.
**Option B:** The quadriceps tendon, while an important stabilizer of the knee, does not directly prevent posterior gliding of the tibia on the femur.
**Option C:** The medial meniscus, although an important structure within the knee joint, is not primarily responsible for preventing posterior gliding of the tibia on the femur.

**Clinical Pearl / High-Yield Fact**
The medial collateral ligament is often injured in valgus stress injuries, which can compromise the stability of the knee joint and lead to excessive posterior gliding of the tibia on the femur.

**Correct Answer: D. Medial collateral ligament. Medial collateral ligament.**