Which muscle is primarily involved in extending the elbow?

The muscle primarily involved in extending the elbow is the triceps brachii. This muscle is located on the posterior side of the arm and plays a crucial role in the extension of the forearm at the elbow joint. When the triceps contracts, it pulls on the olecranon process of the ulna, resulting in the straightening of the arm.

The primary function of the triceps is to counteract flexion caused by the biceps brachii and other flexor muscles. While the biceps primarily facilitates elbow flexion, the triceps serves as the chief extensor, making it essential for actions that require pushing or straightening the arm. This distinct role of the triceps distinguishes it from other muscles listed, such as the latissimus dorsi, which mostly influences the shoulder joint, and the flexor muscles, which are responsible for bending the elbow rather than extending it.