What nerve innervates the muscle responsible for the abduction of the thumb?

The muscle responsible for the abduction of the thumb is the abductor pollicis brevis, which is primarily innervated by the median nerve. This muscle plays a crucial role in thumb movements, allowing for the thumb to be moved away from the palm, which is essential for various hand functions, including grasp and opposition.

The median nerve's action in innervating this muscle highlights its importance in fine motor skills of the hand, especially regarding pinch grips and other intricate hand motions. Understanding the innervation of thumb muscles is vital for diagnosing and treating conditions that may impair hand function, particularly those involving nerve injuries or entrapments.

While the other nerves listed play significant roles in the innervation of different muscles in the arm and hand, they do not innervate the abductor pollicis brevis. This emphasizes the importance of understanding specific muscle innervations in neuroanatomy and their clinical relevance.