This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ocular motility and squint, Subject name: Ophthalmology
Longest and thinnest extrocular muscle - 
Select and explain. 
A. SR, B. IR, C. SO, D. IO
C: SO
Answer: C: SO 
Explanation: SO arises from the bone above and medial to the optic foramina. It runs forward and turns around a pulley- " the trochlea" and is inseed in the upper and outer pa of the sclera behind the equator. Ref;A.K.Khurana; 6th edition;Page no:336