In adult women, when the nipple is sunken beneath the skin surface of the areola and does not protrude from the areola plane, resulting in a large orifice shape, it is called nipple invagination. The degree of nipple invagination varies from a receding nipple to a concave nipple or even an overturned nipple in severe cases. The nipple is not only an obstacle to the beauty of the breast, but also to the function of breastfeeding, and it is difficult to clean the local area, the sunken part is easy to hide dirt and often cause local infection, and the ducts of the breast are connected to the sunken place, inflammation can spread to the breast and cause mastitis, so it should be corrected. The nipple invagination not only affects the overall beauty of the breast but also prevents normal breastfeeding and affects the normal growth and development of the baby; some statistics show that the incidence of breast cancer is higher in women who are not breastfeeding than in those who are breastfeeding normally; the invagination of the nipple is not easy to clean because of the accumulation of dirt and causes local erosion and infection or mastitis. Unmarried or married women who have not had children should be prepared for breastfeeding after childbirth, therefore, women with nipple invagination should be treated as soon as possible. The causes of nipple indentation can be classified as congenital or acquired. The specific causes of congenital nipple indentation 1, the nipple and areola smooth muscle dysplasia: the nipple has an opening for the milk duct, the milk duct is surrounded by smooth muscle fibers, the indented nipple is pulled inward around the milk duct and the muscle fiber bundle inserted into the dermis of the nipple. The texture of these muscle bundles differs significantly from that of the milk ducts. The ducts themselves are underdeveloped: underdeveloped ducts fail to ductalize and behave as striae. 3, the lack of support tissue under the nipple is also the cause of nipple invagination. The specific causes of acquired nipple indentation are 1, clothing is too tightly bound. Especially women in the breast development period underwear is too tight, it is easy to lead to nipple indentation. 2, improper use of bras. Bra too small, too tight, use too early, can cause nipple indentation. 3, breast disease, malignant tumor, mastitis, nipple infection, etc.