Breast Anatomy

The developing of breasts in embryo begins around seven to eight weeks after the conception.  At this stage they are just thickening tissues. Between twelve and sixteen weeks after the conception, the cells start to group and lay the foundation of what will be duct and milk producing glands in the future. Some of these tissues become muscle cells and form the nipples and the darkened tissues around them, called the areola. In later stages of the pregnancy, tube like structures are organized from cells and later form milk ducts. This procedure is caused by the mother's hormones. Milk producing glands, called lobules, will mature during the last eight weeks of the pregnancy and secrete a liquid substance called colostrum. Because of the effects of mother's hormones, for a few weeks after birth, swelling under nipple and the discharge of colostrum is noticeable in both male and female infants, but it will subside gradually.

There is no difference between female and male breasts during childhood and up to puberty. As the puberty begins in the females, estrogen is released. This will be accompanied by progesterone when the ovaries mature and become functional. The combination of them causes the breast to form their mature shape. It usually takes three to four years for the procedure to become complete, but it usually is done by the age of sixteen. The tissues continue to mature during lactation, which to some extent protects the breasts cancer.

The mature breast consists of lobules (glands), milk ducts, fat and connective tissue. A group of lobules is called a lobe. There are usually fifteen to twenty of them arranged in a circular pattern emanating from nipples and areola area. Lobes are not arranged evenly and there are more of them in upper outer portions of the breasts. The tenderness that some women experience before their menstrual cycle begins is caused by these tissues. Half the breast cancers appear in this area as well. They turn into milk ducts, which go toward the nipple and areolar area. From there, they change into six to ten collecting ducts. They connect with the outside through the nipples. This is the passage milk goes through during the breast feeding.

The way lobes arrange differ from woman to woman. They might also be different from side to side in each individual. The breast fat surrounds the lobes. Unlike the lobes that feel somewhat nodular, the surrounding fat is soft.  The difference in their densities makes mammographic imaging possible and allows for palpating. Unless they are inflamed, filled with milk or there is a tumor, the ducts are not palpable.

The amount of the fat in the breasts in younger women is very low. Glandular tissues are more noticeable in them and that makes them firmer. As women age, the lobes are replaced by fat. Loss of estrogen during menopause is the major reason for this replacement of fat. The mammography is more accurate at this time as the breasts are softer.

The glandular tissues are much more sensitive than the other components of the breasts and are more influenced by hormones. Therefore, they change dramatically during the menstrual cycle. Before the start of menstruation, as the estrogen and progesterone are at their highest level, these changes are more dramatic. Breasts become tender and softer as these hormones subside after the cycle. That is the ideal time for a mammogram or self examination.

By the start of menopause, the estrogen reduces and most of the breast tissues turn into fat. Therefore, any change in the body weight has dramatic influences on the shape and size of the breasts.

There are some abnormalities present from the birth in the breasts. Accessory nipples or breast tissues are probably the most common one of them, but it less recognized and occurs in two to six percent of the women. They could be anywhere along the milk line. Milk line only exists in fetuses. It is a tissue developing into breasts, starting from underarm and ending in groin. There are not important at all.

Another one of these abnormalities, which is very rare, is the absence or underdevelopment of one or both of the breasts. Usually the nipple is present at the site of the abnormality. Plastic surgery is a solution to this problem. Usually this abnormality comes along with muscle and rib cage problems as well.