In carpal tunnel syndrome, numbness and tingling most commonly involve which digits?

• A. Little finger and ring finger
• B. Ring finger and small finger
• C. Thumb, index, middle, and radial half of ring finger
• D. Thumb and little finger

Answer: (C)

Compression of the median nerve at the wrist in carpal tunnel syndrome produces sensory loss in its cutaneous distribution: the palmar surfaces of the thumb, index finger, middle finger, and the radial (thumb-side) half of the ring finger. Numbness and tingling in these digits reflect the median nerve’s innervation pattern, especially since CTS often affects these areas first and is commonly worse at night. The little finger and the ulnar-side ring finger are supplied by the ulnar nerve, so they’re not typically involved in CTS. Thus, the digits most commonly affected are the thumb, index, middle, and radial half of the ring finger.