Which muscle assists in elevating the corners of the mouth?

The muscle that assists in elevating the corners of the mouth is the zygomaticus major. This muscle runs from the zygomatic bone to the corners of the mouth and is primarily responsible for the upward movement of the mouth's corners, contributing to expressions such as smiling. Its contraction pulls the mouth's corners laterally and upward, creating a facial expression that conveys happiness or friendliness.

In contrast, the depressor labii inferioris functions to pull the lower lip downward, which is contrary to elevation. The buccinator, while important for actions like chewing and blowing, does not contribute to elevating the corners of the mouth but instead helps in manipulating food within the mouth. The temporalis muscle, primarily involved in jaw movement (specifically chewing), does not play a role in facial expressions or mouth elevation.

This distinction clarifies why the zygomaticus major is the correct choice, effectively highlighting its role in facial expressions and movements associated with smiling.