What is the primary action of the triceps brachii muscle?

The primary action of the triceps brachii muscle is elbow extension. This muscle is located at the back of the upper arm and is primarily responsible for straightening the elbow joint. When the triceps contract, they pull on the olecranon process of the ulna, effectively extending the arm at the elbow.

Understanding the role of the triceps brachii is crucial, especially in activities that require pushing or extending movements, such as pushing off from a surface or performing overhead lifts. This muscle plays a significant role in stabilizing the elbow during these actions as well.

Elbow flexion is primarily performed by muscles such as the biceps brachii and brachialis, while shoulder flexion and shoulder abduction involve muscles like the deltoids and pectoralis major. Therefore, the triceps brachii's specific function is focused on extending the elbow, distinguishing it from those other actions.