Elbow flexion is primarily performed by which muscles, with assistance from which?

Elbow flexion is primarily performed by which muscles, with assistance from which?

• A. Brachialis and brachioradialis are primary, with assistance from biceps.
• B. Biceps brachii and brachialis are primary, with assistance from brachioradialis.
• C. Biceps brachii alone.
• D. Brachioradialis and brachialis.

Answer: (B)

Elbow flexion is driven mainly by two muscles that cross the elbow and shorten to bring the forearm toward the upper arm: the brachialis and the biceps brachii. The brachialis sits deep to the biceps and attaches from the humerus to the ulna, making it a pure elbow flexor that works regardless of how the forearm is rotated. The biceps brachii also crosses the shoulder and acts as a forearm flexor, with its effectiveness enhanced when the forearm is supinated. The brachioradialis, while a helpful elbow flexor, especially when the forearm is in a neutral position, acts more as a synergist rather than a primary mover. Therefore, the best description is that the primary elbow flexors are the biceps brachii and brachialis, with the brachioradialis providing assistance.

Elbow flexion is driven mainly by two muscles that cross the elbow and shorten to bring the forearm toward the upper arm: the brachialis and the biceps brachii. The brachialis sits deep to the biceps and attaches from the humerus to the ulna, making it a pure elbow flexor that works regardless of how the forearm is rotated. The biceps brachii also crosses the shoulder and acts as a forearm flexor, with its effectiveness enhanced when the forearm is supinated. The brachioradialis, while a helpful elbow flexor, especially when the forearm is in a neutral position, acts more as a synergist rather than a primary mover. Therefore, the best description is that the primary elbow flexors are the biceps brachii and brachialis, with the brachioradialis providing assistance.