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
[{'content': 'Locking of the knee joint occurs with all except- \nSelect and explain. \nA. Vastus intermedius, B. Vastus medialis, C. Popliteus, D. Rectus femoris', 'role': 'user'}, {'content': 'Answer: C \nExplanation: 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.\nQuadriceps femoris- Vastus medialis, vastus lateralis, vastus intermedius, rectus femoris. Unlocking occurs with popliteus.', 'role': 'assistant'}]