The labial red line of the upper lip is arched, which is called labial arch. Slightly below the center line, slightly protruding forward is called kerf (kerf). The highest point of the labial arch on both sides is called the labial peak. The middle lip of the upper lip is red and beaded, which is called lip bead. People with lip bead have vivid lips and strong three-dimensional sense. For the flat upper lip, the effect will be more obvious after surgical reconstruction of lip bead.