What’s the platysma muscle under my chin?

The platysma muscle is a thin sheet of muscle that stretches from your lower face to your collarbone. It’s primarily responsible for the movement in your lower face. Your skin’s loss of elasticity—usually caused by aging—can make the skin sag over the platysma muscle, creating what are called “platysmal bands.” Also, If the platysma muscle weakens, that also causes skin droop and the appearance of bands.

A neck lift can tighten the skin and platysmal muscle at their weakest points, making the skin tighter and smoother, and giving you a sharper jawline.