Which muscle inserts into the radial tuberosity?

Which muscle inserts into the radial tuberosity?

• A. Brachialis
• B. Brachioradialis
• C. Biceps Brachii
• D. Pronator Teres

Answer: (C)

Muscle attachments determine its action. The radial tuberosity on the radius is where the tendon of a major elbow flexor inserts. The biceps brachii attaches its tendon at this site (with the bicipital aponeurosis spreading distally), so it is the primary muscle responsible for flexing the elbow, especially when the forearm is supinated. The other muscles don’t insert there. Brachialis attaches to the ulna, not the radius, and drives elbow flexion regardless of forearm position. Brachioradialis attaches to the distal radius near the styloid process and acts mainly to flex the elbow in a neutral forearm position. Pronator teres attaches to the lateral mid-radius and the ulna, aiding pronation and some elbow flexion, but not inserting into the radial tuberosity.

Muscle attachments determine its action. The radial tuberosity on the radius is where the tendon of a major elbow flexor inserts. The biceps brachii attaches its tendon at this site (with the bicipital aponeurosis spreading distally), so it is the primary muscle responsible for flexing the elbow, especially when the forearm is supinated.

The other muscles don’t insert there. Brachialis attaches to the ulna, not the radius, and drives elbow flexion regardless of forearm position. Brachioradialis attaches to the distal radius near the styloid process and acts mainly to flex the elbow in a neutral forearm position. Pronator teres attaches to the lateral mid-radius and the ulna, aiding pronation and some elbow flexion, but not inserting into the radial tuberosity.