First, the main causes of primary nipple invagination
1. nipple areola smooth muscle dysplasia: the nipple has an opening of mammary duct, and there are smooth muscle fibers around the mammary duct. The invaginated nipple is pulled inward by the muscle fiber bundles around the mammary duct and inserted into the nipple dermis. The texture of these muscle bundles is obviously different from that of mammary ducts.
2. The mammary duct itself is hypoplastic: the hypoplastic mammary duct can't be transported, and it shows a cord shape.
3. The lack of supporting tissue under nipple is also the cause of nipple invagination.
Second, the main causes of secondary nipple invagination
Secondary nipple invagination (acquired nipple invagination) is rare, because the nipple is pulled by the pathological tissue in the breast, or the abdomen is unreasonable or the bra is worn too tightly. Diseases caused by diseases are more common in inflammation, tumors and other diseases, which invade the ducts, ligaments and fascia of the breast and contract the invaded ducts, ligaments and fascia; Unreasonable corset or tight bra occurs in adolescence, which leads to breast dysplasia and acquired nipple invagination due to tight chest and poor blood circulation.
In acquired nipple inversion, infection is one of the main factors, mainly mammary duct inflammation with fibrous scar contracture, which affects its normal development and causes nipple inversion.
Breast malignant tumor has inverted nipple, which has different meanings. Women with normal breasts should be examined by mammography if they have nipple invagination without obvious reasons, which is helpful for the diagnosis of this kind of nipple invagination.
Breast surgery can also lead to nipple inversion, which is a nipple deformity. When using dermal pedicle in breast reduction plastic surgery, tension and scar contraction can also cause nipple invagination.
The most common specific reasons for nipple depression are as follows:
1, the clothes are too tight. In particular, women's underwear is too tight during breast development, which easily leads to nipple depression.
2. Improper use of bra. If the bra is too small, too tight and used too early, it will cause nipple depression.
3. Nipple depression is also related to heredity. Clinical observation shows that the incidence of nipple depression in the next generation of mothers with a history of nipple depression and their mothers' generation may be higher than that of normal people.