The shape and structure of breasts

Breasts are composed of skin, fibrous tissue, adipose tissue, and mammary glands. Adipose tissue is mainly located under the skin. The fibrous tissue mainly surrounds the mammary gland but does not form a complete capsule.

A lactation organ unique to humans and mammals. In humans, it is located in the fourth intercostal space at the midclavicular line, one on each side. It is not obvious in normal children and men. Women grow up during puberty due to the stimulation of sex hormones. The breasts of adult women are hemispherical, the nipples are cylindrical, the skin in the central part is light red, and there are sebaceous glands called areola.

The inside of the breast is mainly composed of 15 to 20 gland (breast) lobules and fatty tissue. The glands are arranged radially, and their lactiferous ducts face the areola and open into the nipple. The glands are most developed during pregnancy and lactation, and the breasts are enlarged, protruding forward or drooping; the areola is enlarged and darkened, and veins can be seen on the surface of the breast skin. After menopause, the ovaries cease activity, and the breast volume and fat degenerate and are replaced by fibrous tissue.

Extended information:

Affected by factors such as region and race, the time at which female breasts begin to develop varies. Most female breasts begin to develop between the ages of 8 and 13, and become fully mature between the ages of 14 and 18. Breast development mostly starts from the left side, and it takes about 3-5 years from initial development to full maturity.

The first period (1 to 9 years old): Before puberty, the breasts have not yet developed.

The second stage (10 to 11 years old): In the early stage of breast development, the breast germ under the nipple begins to grow, showing an obvious dome-shaped bulge.

The third stage (12 to 13 years old): The breasts become round and adult-like, but still small.

The fourth stage (14-15 years old): The breasts enlarge rapidly, and the nipples and areola protrude forward, shaped like small balls.

The fifth stage (16-18 years old): Normal adult breasts form, and the small balls of the nipple and areola merge into the round shape of the breast.

Baidu Encyclopedia - Breasts