What muscle is positioned below the lower lip and pulls the lip down or to the side?

The muscle positioned below the lower lip that pulls the lip down or to the side is the Quadratus labii inferioris. This muscle plays a significant role in facial expressions, specifically in actions that involve lowering the lower lip or creating a frowning look. Its name comes from its location and function: "quadratus" suggesting a quadrilateral shape and "labii inferioris" indicating its connection to the lower lip.

The role of the Quadratus labii inferioris is particularly important in esthetic practices, as understanding facial muscular anatomy can help practitioners recognize how to enhance or alter expressions through procedures. By being aware of this muscle's function, estheticians can better anticipate how treatments might impact the appearance of the mouth and overall facial aesthetics.