Which muscles are responsible for forearm supination?

Which muscles are responsible for forearm supination?

• A. Pronator teres
• B. Brachialis
• C. Deltoid
• D. Supinator and Biceps Brachii

Answer: (D)

Supination of the forearm is the action of turning the palm up by rotating the radius over the ulna at the radioulnar joints. The primary muscles that accomplish this are the supinator and the biceps brachii. The supinator wraps around the upper radius and pulls it into a supinated position, especially when the elbow is extended. The biceps brachii, though famous as an elbow flexor, has a strong tendon attached to the radial tuberosity and, with the elbow flexed, its contraction effectively twists the radius to produce supination. By contrast, the pronator teres mainly pronates the forearm, the brachialis focuses on elbow flexion, and the deltoid is a shoulder muscle and does not rotate the forearm. So the muscles responsible for forearm supination are the supinator and the biceps brachii.

Supination of the forearm is the action of turning the palm up by rotating the radius over the ulna at the radioulnar joints. The primary muscles that accomplish this are the supinator and the biceps brachii. The supinator wraps around the upper radius and pulls it into a supinated position, especially when the elbow is extended. The biceps brachii, though famous as an elbow flexor, has a strong tendon attached to the radial tuberosity and, with the elbow flexed, its contraction effectively twists the radius to produce supination. By contrast, the pronator teres mainly pronates the forearm, the brachialis focuses on elbow flexion, and the deltoid is a shoulder muscle and does not rotate the forearm. So the muscles responsible for forearm supination are the supinator and the biceps brachii.