Which nerve corresponds to the sensory distribution of the thumb and thenar area?

The correct answer is the median nerve. This nerve plays a crucial role in the sensory distribution of the thumb and the thenar eminence, which consists of the muscles at the base of the thumb responsible for its movement. The median nerve innervates the skin on the palmar side of the thumb and the first two or three fingers, along with the corresponding part of the palm, making it essential for sensation in these areas.

The significance of the median nerve in terms of hand function and sensation cannot be overstated, as it enables fine motor skills and tactile feedback necessary for grasping and manipulating objects. Damage to this nerve can lead to decreased sensation or pain in the thumb and thenar area, illustrating its importance in both sensory perception and motor control.

In contrast, the ulnar nerve primarily supplies the intrinsic muscles of the hand and provides sensation to the ulnar side of the hand (the little finger and part of the ring finger). The radial nerve is more involved with the extensor muscles of the forearm and the back of the hand. The medial antebrachial nerve, while it provides sensory innervation to part of the forearm, does not play a role in the sensory distribution of the thumb or thenar area.