Which muscles serve as prime movers for wrist flexion?

• A. Flexor Carpi Radialis & Flexor Carpi Ulnaris
• B. Flexor Digitorum Superficialis & Flexor Pollicis Longus
• C. Extensor Carpi Radialis Longus & Extensor Carpi Radialis Brevis
• D. Palmaris Longus & Flexor Digitorum Profundus

Answer: (A)

Wrist flexion is produced most effectively by two powerful forearm flexors that cross the radiocarpal joint: the flexor carpi radialis and the flexor carpi ulnaris. These muscles originate from the common flexor tendon on the medial side of the elbow and insert on the metacarpals and nearby carpal bones, allowing the hand to move toward the forearm when they contract. Flexor carpi radialis mainly adds flexion with some radial (thumb-side) deviation, while flexor carpi ulnaris adds flexion with some ulnar (pinky-side) deviation. Together, they provide the strongest flexion torque at the wrist, making them the primary movers for wrist flexion. Other muscles listed either focus on finger or thumb flexion (which can indirectly assist wrist flexion) or extend the wrist, so they are not the prime wrist flexors. Palmaris longus, when present, is a weak flexor and not a primary contributor.