Which of the following muscles raises each labial commissure of the lips to contribute to a patient's smile?

Question

Quizplus · Accepted Answer

The zygomaticus major muscle is responsible for raising each labial commissure of the lips, which contributes to a patient's smile. It originates from the zygomatic bone and inserts into the angle of the mouth. When it contracts, it pulls the corner of the mouth upward and backward, elevating the labial commissure and creating a smile. The buccinator muscle helps to keep the cheeks tight against the teeth and is not directly involved in smiling. The platysma muscle is involved in facial expressions of sadness or tension and is not typically activated in a smile. The epicranius muscle is responsible for raising the eyebrows and is not involved in smiling.

Which of the Following Muscles Raises Each Labial Commissure of the Lips