Which muscle is targeted to improve the appearance of a furrow between the brows?

The corrugator muscle is the correct choice because it plays a key role in the formation of vertical lines or furrows between the brows, commonly referred to as "frown lines." This muscle is located above the eyebrow and is responsible for drawing the eyebrows down and together, contributing to expressions of concern or concentration. By targeting and effectively relaxing or strengthening the corrugator muscle through various esthetic treatments, practitioners can help reduce the prominence of these furrows, leading to a smoother and more youthful appearance.

In contrast, while the frontalis muscle is involved in raising the eyebrows and can contribute to forehead wrinkles, it does not directly affect the furrow between the brows. The orbicularis oculi muscle primarily encircles the eye and is associated with the formation of crow's feet rather than the furrow itself. The platysma muscle, located in the neck and lower facial region, is primarily responsible for movements of the neck and jawline and does not influence the furrow between the brows. By understanding the specific functions of each muscle in facial expression, one can better determine how to target the issue of furrows effectively.