Hypoesthesia testing shows which finding suggestive of carpal tunnel syndrome?

Hypoesthesia testing shows which finding suggestive of carpal tunnel syndrome?

• A. Pinky finger sharper than the thumb
• B. Thumb significantly numb
• C. Wrist swelling without numbness
• D. Temperature difference across the wrist

Answer: (A)

The key idea is the sensory map of the hand and how carpal tunnel affects the median nerve. Carpal tunnel syndrome causes hypoesthesia in the median nerve distribution—that is, the thumb, index, middle, and the radial half of the ring finger. When you test sensation, a relative difference between fingers is highly informative: the pinky finger (which is supplied by the ulnar nerve) remains relatively sharp, while the thumb loses sensation. This pattern points to median nerve impairment at the carpal tunnel. So the finding that the pinky is sharper than the thumb reflects preserved ulnar-nerve sensation with impaired median-nerve sensation in the thumb area, which fits carpal tunnel syndrome. In contrast, swelling without numbness or a simple temperature difference isn’t a typical sign, and while a numb thumb can occur in CTS, the relative comparison across digits is the classic indicator tested in hypoesthesia assessments.

The key idea is the sensory map of the hand and how carpal tunnel affects the median nerve. Carpal tunnel syndrome causes hypoesthesia in the median nerve distribution—that is, the thumb, index, middle, and the radial half of the ring finger. When you test sensation, a relative difference between fingers is highly informative: the pinky finger (which is supplied by the ulnar nerve) remains relatively sharp, while the thumb loses sensation. This pattern points to median nerve impairment at the carpal tunnel.

So the finding that the pinky is sharper than the thumb reflects preserved ulnar-nerve sensation with impaired median-nerve sensation in the thumb area, which fits carpal tunnel syndrome. In contrast, swelling without numbness or a simple temperature difference isn’t a typical sign, and while a numb thumb can occur in CTS, the relative comparison across digits is the classic indicator tested in hypoesthesia assessments.