What type of action does the triceps muscle perform at the elbow joint?

The triceps muscle is primarily responsible for extension at the elbow joint. This muscle is located at the back of the upper arm and functions by contracting to straighten the arm at the elbow. When the triceps contract, they pull on the olecranon process of the ulna, which results in the extension of the forearm relative to the upper arm. This action is crucial not only in isolated movements such as pushing or throwing but also supports stability during various upper body exercises and functional movements.

In the context of the provided choices, flexion refers to bending the elbow, which is primarily performed by the biceps and other flexor muscles. Stabilization typically involves keeping a joint in a fixed position, and while the triceps do contribute to stability, it is not their primary action at the elbow. Abduction involves movement away from the midline of the body, which is not relevant to the actions of the triceps at the elbow joint. Thus, the primary and defining action of the triceps at the elbow is extension.