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: Orthopaedics
In Carpal tunnel syndrome, features are of - 
Select and explain. 
A. Compression of ulnar nerve, B. Compression of median nerve under the flexor retinaculum, C. Anaesthesia over thenar eminence, D. Atrophy of hypothenar muscles
B: Compression of median nerve under the flexor retinaculum
Answer: B: Compression of median nerve under the flexor retinaculum 
Explanation: The carpal bones form an arch which is convex on the dorsal side of the hand and concave on the palmar side.
The groove on the palmar side is covered by flexor retinaculum, thus forming carpal tunnel.
Carpal tunnel syndrome is caused by compression of median nerve.