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: Anatomy
Carpal tunnel syndrome involves 
Select and explain. 
A. Median nerve, B. Anterior interosseous nerve, C. Ulnar nerve, D. Radial nerve
A: Median nerve
Answer: A: Median nerve 
Explanation: CARPAL TUNNEL SYNDROME:-

Injury to median nerve in carpal tunnel.

Causes:-
Tenosynovitis of flexor tendons.
Myxedema
Retention of fluid in pregnancy 
Fracture dislocation of lunate bone.
Osteoarthritis of wrist.
Symptoms:-
1. Feeling of burning pain or " pins & needles " along lateral 3 and half digits especially at night.
2. Weakness of thenar muscles.
3. No sensory loss over thenar eminence.
4. Ape thumb deformity if left untreated.
5. Positive phalens and tinel's sign.
Phalen's sign-flexion of both wrists against each other for one minute reproduces the symptoms.
Tinel's sign- percussion over flexor retinaculum reproduces symptoms.