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
Proximal muscle weakness is not a feature of 
Select and explain. 
A. Polymyositis, B. Myotonic dystrophy, C. Becker's muscular dystrophy, D. Duchene's muscular dystrophy
B: Myotonic dystrophy
Answer: B: Myotonic dystrophy 
Explanation: In Myotonic dystrophy the Muscles affected are Face(including ptosis), sternocleidomastoids, distal limb, generalised later. In all other above mentioned options the proximal muscles are affected. Reference : Harrison20th edition pg 2278