Arkansas Esthetician Practice Exam 2025 - Free Esthetician Practice Questions and Study Guide.

The function of the risorius muscle is to draw the corners of the mouth up and out, creating a smile. This function is unique to this muscle, which means options A, B, and D are incorrect. Option A's function belongs to the pronator teres muscle, which is responsible for rotating the forearm to turn the palm down. Option B's function belongs to the orbicularis oris muscle, which creates facial expressions such as puckering and wrinkling the lips. Option D's function belongs to the orbicularis oculi muscle, which is responsible for closing the eyelid. It is important to distinguish between these muscles and their functions to better understand the functions of the risorius muscle. This is why option C is the correct answer.