In a classic case of carpal tunnel syndrome, the median nerve is compressed beneath the transverse carpal ligament. Which specific sensory territory of the hand is classically spared from numbness because its nerve branch arises proximal to the tunnel?

Explanation:
The correct option is d. The palmar cutaneous branch of the median nerve provides sensation to the skin directly over the base of the thenar eminence (the palmar triangle). This specific nerve branch exits the main trunk of the median nerve approximately 5 to 7 cm proximal to the wrist crease. It runs superficially, traveling above and completely outside of the transverse carpal ligament. Therefore, in true carpal tunnel syndrome, this nerve branch is never compressed, and sensation over the thenar eminence remains perfectly normal, helping differentiate CTS from a more proximal median nerve lesion (like pronator syndrome). Reference: Campbell's Operative Orthopaedics.