Which action is associated with the biceps brachii?

• A. Elbow extension
• B. Wrist flexion
• C. Pronation
• D. Elbow flexion

Answer: (D)

The biceps brachii mainly bends the elbow. It crosses the elbow joint in front of the arm, so when it contracts it pulls the forearm up toward the upper arm, producing elbow flexion. It also helps rotate the forearm to turn the palm upward (supination) when the elbow is flexed. It does not extend the elbow—this motion is carried out by the triceps. Wrist flexion is carried out by forearm muscles that cross the wrist, and pronation (turning the palm downward) is produced by pronator muscles. So elbow flexion is the action most closely associated with the biceps brachii.