Washington Esthetician State Board Practice Exam

What is the primary area supplied by the radial nerve and its branches?

1. The forearm and thumb

2. The back of the hand, thumb, and side of the arm

3. The fingers and wrist

4. The elbow and shoulder

The correct answer is: The back of the hand, thumb, and side of the arm

The radial nerve is responsible for providing motor and sensory innervation primarily to the posterior aspect of the arm and forearm, extending down to the back of the hand. It innervates muscles that allow for the extension of the elbow, wrist, and fingers, and it supplies sensation to the skin over the back of the hand, specifically the thumb and the radial side of the index finger and part of the middle finger. The statement regarding the back of the hand, thumb, and side of the arm accurately encompasses the key areas affected by the radial nerve's distribution. In contrast, other answer choices might suggest a coverage of areas that do not fall exclusively under the radial nerve's domain. For example, the forearm and thumb focus on a more limited area, and options involving the elbow and shoulder are not relevant, as they are more associated with other nerves like the musculocutaneous and axillary nerves. Therefore, B is the best choice as it reflects the accurate sensory and motor supply of the radial nerve and its branches.