Which muscle is responsible for elevating the lower lip?

The mentalis muscle is crucial for elevating the lower lip. This muscle is located at the tip of the chin and plays a vital role in various facial expressions, particularly in actions related to pouting or protruding the lower lip. When the mentalis contracts, it lifts the lower lip upwards and can also cause the skin of the chin to wrinkle, contributing to the expression of doubt or contemplation.

The orbicularis oris primarily encircles the mouth and is involved in closing and shaping the lips rather than elevating the lower lip specifically. The buccinator muscle helps with chewing by keeping food between the teeth and does not function to elevate the lip. The risorius muscle assists in drawing the corners of the mouth laterally, contributing to expressions like smiling, but does not elevate the lower lip itself. Therefore, the mentalis is the correct muscle associated with the action of elevating the lower lip.