Which nerve is primarily responsible for forearm pronation, finger flexion, and thumb motion?

Which nerve is primarily responsible for forearm pronation, finger flexion, and thumb motion?

• A. Axillary
• B. Musculocutaneous
• C. Median
• D. Radial

Answer: (C)

The median nerve best explains these actions because it supplies the key forearm and hand muscles involved. Forearm pronation is done by pronator teres and pronator quadratus, both innervated by the median nerve (via the anterior interosseous branch). Finger flexion relies on flexor digitorum superficialis and the lateral part of flexor digitorum profundus, which receive median nerve input. Thumb motion depends on the thenar muscles (abductor pollicis brevis, opponens pollicis, flexor pollicis brevis) supplied by the recurrent branch of the median nerve, plus flexor pollicis longus via the anterior interosseous branch. While other nerves contribute to related functions, the median nerve uniquely covers these movements, making it the correct choice.

The median nerve best explains these actions because it supplies the key forearm and hand muscles involved. Forearm pronation is done by pronator teres and pronator quadratus, both innervated by the median nerve (via the anterior interosseous branch). Finger flexion relies on flexor digitorum superficialis and the lateral part of flexor digitorum profundus, which receive median nerve input. Thumb motion depends on the thenar muscles (abductor pollicis brevis, opponens pollicis, flexor pollicis brevis) supplied by the recurrent branch of the median nerve, plus flexor pollicis longus via the anterior interosseous branch. While other nerves contribute to related functions, the median nerve uniquely covers these movements, making it the correct choice.