This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
Locking of the knee joint occurs with all except- 
Select and explain. 
A. Vastus intermedius, B. Vastus medialis, C. Popliteus, D. Rectus femoris
C: Popliteus
Answer: C: Popliteus 
Explanation: During last stages of extension, femur rotates medially on tibia due to quadriceps femoris to lock the knee joint. Femur rotates laterally on tibia during flexion.
Quadriceps femoris- Vastus medialis, vastus lateralis, vastus intermedius, rectus femoris. Unlocking occurs with popliteus.