The main components of breast

Breasts are very important organs for nurturing offspring. For women, it is important to take good care of their breasts and ensure breast health. The main component of breasts is fat, and they are not reproductive organs. Nowadays, there are many kinds of breast diseases. It is important to have regular check-ups and actively prevent breast diseases. Having a comprehensive understanding of breast conditions will help you better deal with possible problems.

The breast is composed of skin, fibrous tissue, fat 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. There are fibrous tissue septa embedded between the mammary lobes, dividing the gland into 15 to 20 lobes of Mammary gland. Each gland lobe has an excretory duct, called the lactiferous duct, which runs to the nipple. Near the nipple, the lactiferous duct swells into the lactiferous sinus, whose end becomes thinner and opens into the nipple. The mammary lobes and lactiferous ducts are arranged radially with the nipple as the center. During breast surgery, radial incisions should be made as much as possible to reduce damage to the mammary lobes and milk ducts. The fibrous tissue around the breast sends small fiber bundles deep into the breast and connects to the pectoral fascia. Small fiber bundles also extend from the fibrous tissue on the surface of the breast to connect to the skin and nipple. These fiber bundles in the upper part of the breast are more developed. These fiber bundles are called suspensory ligaments of breast or Cooper Ligament, which stabilize the breast. In the early stages of breast cancer, the suspensory ligaments of the breast are invaded, the fibrous tissue proliferates, and the ligaments shorten, causing some depressions in the surface skin. In the late stage of cancer, due to obstruction of lymphatic return, tissue edema occurs, and the cancerous area is tightly adhered to the skin, especially the hair follicles of the skin are more tightly adhered to the deeper layer, causing many small depressions to appear on the skin, and the skin appears orange peel-like. These features aid in the diagnosis of breast cancer.

Internal structure of the breast: The breast is mainly composed of glands, ducts, adipose tissue and fibrous tissue. The mammary gland is composed of 15 to 20 lobes, each lobe is divided into several lobules, and each lobule is composed of 10 to 100 alveoli. The alveoli are closely arranged around the small milk ducts, and their openings are connected to the small milk ducts. Many small milk ducts gather into interlobular milk ducts, and multiple interlobular milk ducts gather into a mammary duct of an entire gland lobe, also known as the lactiferous duct. There are 15 to 20 lactiferous ducts, arranged radially with the nipple as the center, converging at the areola, and opening at the nipple, called the lactiferous foramen. The lactiferous duct is narrower at the nipple, and then expands into an ampulla, called the lactiferous sinus, which can store milk. The opening of the mammary duct is composed of stratified squamous epithelial cells, the narrow part is composed of transitional epithelium, the ducts at all levels below the ampulla are composed of double-layer columnar epithelium or single-layer columnar epithelium, the terminal ducts near the alveoli are composed of cuboidal epithelium, and the alveoli are lined with cuboidal epithelium. The fat tissue in the breast is wrapped around the mammary gland in a sac-like shape, forming a hemispherical whole. This sac-like fat tissue is called a fat cyst. The thickness of fat cysts can vary greatly from person to person due to age, childbirth and other reasons. The amount of fat tissue is one of the important factors that determine breast size.

External structure of the breast: The nipple is composed of dense connective tissue and smooth muscle. The smooth muscle is arranged in a circular or radial pattern. When there is mechanical stimulation, the smooth muscle contracts, causing the nipple to erect and squeezing the ducts and lactiferous sinuses to discharge their contents. The skin of the areola has hair and glands. The glands include sweat glands, sebaceous glands and mammary glands. Its sebaceous glands, also known as areola glands, are large and superficial. Their secretions have the function of protecting the skin and lubricating nipples and baby's lips.

The mammary gland is located between the superficial and deep layers of the subcutaneous superficial fascia. The superficial fascia extends into the breast tissue to form lobular septa, one end of which is connected to the pectoralis muscle fascia. The other end is connected to the skin, fixing the mammary gland in the subcutaneous tissue of the chest. These fibrous connective tissues that support and hold the breast in place are called suspensory ligaments. The deep layer of the superficial fascia is located deep in the breast and is connected to the superficial layer of the pectoralis major fascia by loose tissue. It allows the breast to be relatively fixed while having a certain degree of mobility on the chest wall. Sometimes, part of the breast gland can penetrate through the loose tissue into the superficial layer of the pectoralis major muscle. Therefore, during radical surgery for breast cancer, the pectoralis major muscle fascia and muscle should be removed together.

1. Position and morphological structure: Breasts are underdeveloped in children and males, and the breasts of adolescent women who are not breastfeeding are hemispherical. Located at the height of the 2nd to 6th ribs, between the superficial and deep layers of the superficial fascia, on the surface of the pectoral fascia, extending from the parasternal line outward to the mid-axillary line. The breasts contain milk glands and fat. The mammary gland is divided into 15 to 20 lobes by connective tissue, and each lobe is divided into several lobules. Each gland lobe has a lactiferous duct, which is arranged radially with the nipple as the center and opens at the nipple. When draining a breast abscess by incision, radial incisions should be made to avoid cutting the milk ducts, and attention should be paid to separating the connective tissue intervals to facilitate drainage. There are many fiber bundles perpendicular to the skin in the connective tissue between the glandular lobes, one end of which is connected to the skin and the superficial layer of the superficial fascia, and the other end is connected to the deep layer of the superficial fascia, which is called the suspensory ligament of the breast or Cooper's ligament. Because the two ends of the ligament are fixed and cannot stretch, breast cancer causes depression in the skin there. There is a gap between the deep layer of the superficial fascia and the pectoral muscle fascia, called the retromammary space, which contains loose connective tissue, fat and lymphatic vessels. The latter collects lymph from the deep part of the breast. Breast cancer can metastasize to the deep part from here. When inflammation occurs in this space, it tends to spread downward, so low incision and drainage should be performed.

2. Lymphatic return: Women's breasts are rich in lymphatic vessels, which are divided into two groups: superficial and deep. The superficial group was located within the skin and subcutaneously, and the deep group was located around the mammary lobules and within the walls of the lactiferous ducts, with extensive anastomosis between the two groups. The breast lymph mainly flows into the axillary lymph nodes, and some flows into the parasternal lymph nodes, interpectoral lymph nodes and diaphragmatic lymph nodes.