What is the primary action of the triceps brachii?

The primary action of the triceps brachii is elbow extension. The triceps brachii is a large muscle located on the back of the upper arm, consisting of three heads: the long head, lateral head, and medial head. When the muscle contracts, it pulls on the olecranon process of the ulna, resulting in the straightening of the elbow joint. This action is fundamental to many movements, such as pushing or throwing, and is crucial for any activity where the arms need to extend.

Understanding this action is vital for various practical applications, including rehabilitation and strength training, as well as for ensuring proper techniques in sports and everyday activities. The function of the triceps is also essential for balance and stability in upper body movements, indicating its importance in overall arm mechanics.