Under normal circumstances, female breasts can begin to develop during puberty, and the development site should be on the surface of the pectoralis major and pectoralis fascia, from 2-3 ribs upward to 6-7 ribs downward, and the nipples of mature full breasts can usually be located between the 5th ribs, usually presenting as hemispherical or teardrop-shaped, tight, firm, full and elastic. And breast sagging means that women due to age, breastfeeding, hormone secretion abnormalities, trauma and other internal and external factors, resulting in changes in the shape of the breast, the loss of the 2-6th intercostal convexity, showing the nipple sagging, leaving the 5th intercostal state, clinically according to the location of the nipple and breast can be divided into pseudo-sagging and true sagging: a. Pseudo-sagging: that is, the breast may show a sagging state, more The nipple is still horizontal or above the crease with the lower breast wall (i.e., where the breast is connected to the abdomen), that is, pseudo-sagging, which is generally common after women finish breastfeeding, or after unhealthy weight loss resulting in significant weight loss in a short period of time. Second, true sagging: 1, Ⅰ degree: the nipple is lower than the lower breast crease within 1 cm and higher than the lowest point of the breast; 2, Ⅱ degree: the nipple is higher than the lowest point of the breast, but lower than the lower breast crease within 3 cm; 3, Ⅲ degree: the nipple sags more than the lower crease at 3 cm, or is located at the lowest point of the entire breast.