Carpal tunnel syndrome involves
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.
Median nerve
Anterior interosseous nerve
Ulnar nerve
Radial nerve