In addition to elbow flexion, which movement is also a primary action of the biceps brachii?

In addition to elbow flexion, which movement is also a primary action of the biceps brachii?

• A. Pronation
• B. Supination
• C. Adduction
• D. Extension

Answer: (B)

The biceps brachii does more than bend the elbow—it also turns the forearm so the palm faces upward, known as supination. Because it crosses both the elbow and radioulnar joints and attaches to the radius, contracting the biceps rotates the radius around the ulna, producing supination, especially when the elbow is flexed around 90 degrees. Pronation is handled mainly by the pronator muscles, adduction is a different directional movement toward the body's midline, and extension is carried out by the triceps.

The biceps brachii does more than bend the elbow—it also turns the forearm so the palm faces upward, known as supination. Because it crosses both the elbow and radioulnar joints and attaches to the radius, contracting the biceps rotates the radius around the ulna, producing supination, especially when the elbow is flexed around 90 degrees. Pronation is handled mainly by the pronator muscles, adduction is a different directional movement toward the body's midline, and extension is carried out by the triceps.