What is the action of the triceps brachii?

• A. Extend elbow, flex shoulder
• B. Flex elbow
• C. Abduct manus, flex carpus
• D. Abduct digit I, extend carpus

Answer: (A)

The action of the triceps brachii involves extending the elbow joint. The triceps brachii is a large muscle located in the posterior compartment of the arm and is primarily responsible for elbow extension. Its long head also plays a role in shoulder extension when the arm is in certain positions. Therefore, the correct answer encompasses both the extension of the elbow and the potential impact on shoulder movement.

In contrast, the other options describe actions associated with different muscles or movements that do not align with the primary functions of the triceps brachii. For example, flexing the elbow is contrary to the action of the triceps, while movements described in the remaining options are related to other muscle groups in the forearm or hand, which are not relevant to the triceps brachii's function.