What is the primary function of the triceps brachii?

The primary function of the triceps brachii is to extend the arm at the elbow joint. This muscle is located on the posterior aspect of the upper arm and is composed of three heads: the long head, the lateral head, and the medial head. When the triceps brachii contracts, it pulls the forearm backward, straightening the elbow. This action is essential for various movements, such as pushing, throwing, and performing exercises like push-ups or bench presses.

The triceps brachii is crucial for stabilizing the shoulder joint during arm movements as well, playing a vital role in activities requiring upper body strength and coordination. Understanding the function of the triceps helps in grasping how it contributes to overall upper limb movement and strength training.