The mouth and lips are the organ of speech and the gateway to food intake, while it is closely related to the facial expression muscles and therefore also has a highly specialized expression function. The lips speak as well as the eyes and can convey emotions, which is why some people call it the charming point of the face. The shape of the lips is closely related to how well they combine the three basic elements of line, proportion and color. A beautiful lip shape must have characteristics such as coordinated upper and lower lips, proper thickness, smooth curves, and rosy color. Anatomical name: The upper boundary is the bottom of the nose, the lower boundary is the chin-lip groove, and both sides are the nasolabial groove. The upper and lower lips are divided into three parts, one is the skin part (also called white lips), the second is the red part of the lips, the skin is extremely thin, there is no horny layer and pigment, so the blood color of the blood vessels below can be clearly revealed, and the third is the mucous membrane part, inside the lips, part of the oral mucosa, the color is darker, and there is a sense of light and secretion function. From the frontal view, the junction of the skin and mucous membrane of the upper lip forms an arch-shaped curve called the lip arch; the two highest points on the lip arch of equal height are the lip peaks; the lowest point in the center of the two lip peaks is called the lip arch concave; the lip red in the middle of the lip is nodular and prominent called the lip bead, which makes the shape of the lip red more vivid and rich in beauty. In the middle of the upper lip, there is a longitudinal groove whose depth varies from person to person, which is a unique human structure and an important part of the ideal upper lip appearance. Aesthetic parameters: Upper lip height refers to the distance from the bottom of the nose to the peak of the lip. The height of the upper lip for adults in China is between 13 and 22 mm. Thickness of the lips The thickness of the upper and lower lips when the upper and lower lips are lightly closed. The ratio of the thickness of the upper and lower lips is 2:3. The width of the oral fissure is approximately equivalent to the vertical line extending downward from the two pupils when both eyes are looking at each other. The shape of the lip arch is generally classified as bowed, bridged and curved. The most aesthetically pleasing of these is the arch shape. Types of lip aesthetics: thick lips, thin lips, heavy lips, lip bead reconstruction, lip deficiency, lip ectropion, crooked corners of the mouth, small mouth deformity, large mouth deformity, cleft lip and second stage repair, etc.