Hello, female breasts are made up of fat, glands and fibrous tissue. There are blood vessels, mammary ducts, fat, glands and sensory nerves in the breast. Below the gland is pectoralis major, and there is a gap between the gland and pectoralis major, which is clinically called the posterior space of breast tissue. Breast augmentation is to place the breast augmentation prosthesis under pectoralis major or in the posterior space of breast tissue, and the human body should form a coating to wrap the prosthesis.