Numbness on the lateral half of the palm of the hand would indicate a lesion to which nerve?

Numbness in the lateral half of the palm of the hand is typically associated with the median nerve. This is due to the specific areas supplied by this nerve, which is responsible for innervating the majority of the palmar surface of the hand, particularly the thumb, index finger, middle finger, and half of the ring finger. The median nerve also provides sensory innervation to the lateral aspect of the palm.

In cases where there is damage or compression of the median nerve, often experienced in conditions such as carpal tunnel syndrome, individuals may report numbness or tingling sensations in these areas. Understanding this anatomical distribution helps clarify why a lesion affecting the median nerve would result in numbness confined to the lateral half of the palm, reflecting its role in sensory function.

The other nerves listed either do not supply the palm or have different sensory distributions, making them less relevant to the symptoms described. For instance, the ulnar nerve primarily innervates the medial aspect of the hand, the radial nerve is responsible for the posterior aspect of the arm and forearm, and the superficial radial nerve innervates the skin over the lateral dorsal aspect of the hand rather than the palm itself.