Just as we don’t understand the earth when we live on it, probably every woman knows that it is important to have beautiful shapely breasts, but doesn’t really understand it, so see below! Normal adult female breast size ranges from 200 grams to 500 grams. Under normal circumstances, the two sides of the breasts of non-lactating women are not equal in size, but should be basically symmetrical on both sides. The size of the female mammary glands is related to race, heredity, age, nutrition, reproductive status, breastfeeding and other factors. Generally, after breastfeeding, the mammary glands tend to sag or become slightly flattened. In older women, the mammary glands are atrophied and sagging, and are more flaccid. After breastfeeding, due to different breastfeeding habits on both sides of the size of the breast can be significantly different and asymmetric. The breasts are positioned on the body surface between the 2nd and 7th ribs, medially at the sternal border, and laterally at the anterior axillary line, with the tail of the gland pointing to the anterior axillary fold. The breast is hemispherical in shape, with skin on its surface, adipose tissue below the skin, and mammary glandular tissue just below. The glandular tissue is divided into many lobules, each of which contains milk ducts and glands, which are the functional units of lactation. The mammary ducts extend from the deep part of the mammary gland in the direction of the nipple and open centrally on the nipple. The breast lobules are separated by many fibrous septa which are radially distributed. Behind the glands is a layer of loose connective tissue called the posterior breast fascia. Its presence is what ensures that the breast can move up and down on the chest wall. In the deeper tissue is the pectoralis major muscle. Further to the center of the surface are the nipple and areola, which have a more pigmented skin surface. The size of the areola varies from person to person, the diameter is about 15-60 mm. The skin of the areola area has openings for sweat glands, sebaceous glands, areola glands, and a small amount of soft, fine sweat hair growth. The breast cast areola contains more circular and radial smooth muscle fibers surrounding the mammary ducts and connecting to the base of the skin. These muscle fibers also control the opening of the ducts, sweat glands, and sebaceous glands. When these muscle fibers contract, they can cause obstruction of the subcutaneous veins in the nipple areola and bruising, resulting in nipple erection. Since the fibers of these nerves are interwoven into a network and have a complementary compensatory effect on each other, the localization of pain in breast disease is not always very accurate, and sometimes radiates to the neck, armpit, inner upper arm, outer chest and back. In the female breast and nipple areola subcutaneous presence of very rich nerve endings, these nerve endings in the nipple areola subcutaneous formation of a number of Meissners vesicles, which are more sensitive to stimulation. When the skin in this area is stimulated, it can cause smooth muscle contraction under the skin of the nipple areola through nerve reflex, forming contraction and erection of the nipple areola.