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: Ophthalmology
Synergistic muscle for right medial rectus is ? 
Select and explain. 
A. Right lateral rectus, B. Left lateral rectus, C. Right superior rectus, D. Right superior oblique
C: Right superior rectus
Answer: C: Right superior rectus 
Explanation: Ans. is 'c' i.e., Right superior rectus To know this question one should know the difference between synergistic muscles and yoke muscles. Synergists. It refers to the muscles having the same primary action in the same eye e.g.,superior rectus and inferior oblique of the same eye act as synergistic elevators.