Which statements describe the primary movement and insertion of the biceps brachii?

Which statements describe the primary movement and insertion of the biceps brachii?

• A. Insertion at radial tuberosity; Flex elbow and flex the shoulder
• B. Flex elbow and flex the shoulder; Insertion at the radial tuberosity
• C. Extend the elbow; Insertion at radial tuberosity
• D. Pronation of forearm; Insertion at coronoid process

Answer: (B)

The biceps brachii functions across two joints, so its actions include moving the elbow and providing some shoulder assistance. Its tendon inserts on the radial tuberosity (with the bicipital aponeurosis continuing toward the forearm), which is where the force pulls to produce elbow motion. The primary action at the elbow is to flex the elbow, and when the forearm is supinated, the muscle also works to rotate the forearm more effectively. The long head crosses the shoulder joint, so it can contribute to shoulder flexion as well, though elbow flexion is the main movement. So the best description is that the biceps brachii flexes the elbow and can assist shoulder flexion, with insertion at the radial tuberosity. The other statements conflict with this: elbow extension is not a primary action, the coronoid process is not where the biceps inserts, and pronation is not the action of the biceps (it mainly supinates the forearm).

The biceps brachii functions across two joints, so its actions include moving the elbow and providing some shoulder assistance. Its tendon inserts on the radial tuberosity (with the bicipital aponeurosis continuing toward the forearm), which is where the force pulls to produce elbow motion. The primary action at the elbow is to flex the elbow, and when the forearm is supinated, the muscle also works to rotate the forearm more effectively. The long head crosses the shoulder joint, so it can contribute to shoulder flexion as well, though elbow flexion is the main movement.

So the best description is that the biceps brachii flexes the elbow and can assist shoulder flexion, with insertion at the radial tuberosity. The other statements conflict with this: elbow extension is not a primary action, the coronoid process is not where the biceps inserts, and pronation is not the action of the biceps (it mainly supinates the forearm).