Which muscle's primary action is to compress the cheeks for actions such as blowing?

The buccinator muscle plays a crucial role in the function of compressing the cheeks, which is essential for activities such as blowing, chewing, and sucking. Its primary action helps keep food between the teeth while chewing and assists in facial expressions related to various actions, such as playing a wind instrument or blowing a kiss. This muscle is located in the cheek area, and its contraction effectively pushes the cheeks inward, making it vital for oral and facial movements.

In contrast, the mentalis muscle is mainly responsible for elevating and protruding the lower lip, contributing to the pouting expression. The caninus muscle is involved in elevating the corners of the mouth, aiding in facial expressions associated with smiling or sneering, while the zygomaticus muscle assists in smiling and elevating the mouth's corners. None of these perform the primary action of compressing the cheeks like the buccinator does. Thus, the buccinator is the clear choice as it specializes in the functions necessary for blowing and similar actions.