This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.N.S., Subject name: Medicine
In Duchenne's muscular dystrophy, which muscle is not involved : 
Select and explain. 
A. Gastrocnemius, B. Vastus medialis, C. Brachioradialis, D. Infraspinatus
B: Vastus medialis
Answer: B: Vastus medialis 
Explanation: Ans. is 'b' & 'd' Vastus medialis and infraspinatus (Ref. O.P. Ghai, 5/e, p 425; Harrison, 17/e p 2682, 2683 & 16/e, p 2528 (15/e, p 2530)).