Milady Esthetics State Board Practice Test

What role does the radial nerve play in the body?

1. Supplies the thumb side of the arm

2. Controls eye movement

3. Regulates heart rate

4. Is responsible for balance

The correct answer is: Supplies the thumb side of the arm

The radial nerve plays a crucial role in supplying sensation and motor function to parts of the arm. Specifically, it innervates the muscles in the posterior compartment of the arm and forearm, which are responsible for extending the elbow, wrist, and fingers. Additionally, it provides sensory nerve fibers that supply the skin on the back of the arm, the forearm, and the hand, particularly on the thumb side. Therefore, stating that the radial nerve supplies the thumb side of the arm accurately reflects its anatomical functions. The other options refer to different nerves and systems in the body. For example, eye movement is controlled by cranial nerves, such as the oculomotor nerve, while heart rate regulation is managed by the autonomic nervous system and specifically the vagus nerve. Balance is primarily supported by the vestibulocochlear nerve and proprioceptive input from various parts of the body. Understanding the specific functions of the radial nerve helps in recognizing its importance in both motor and sensory activities in the arm.