Breast Anatomy

The breast is composed of adipose tissue (fat), glandular epithelium (tissue that lines the cavities and surfaces of structures throughout the body), blood vessels, lymph glands, supporting collagenous fibers, capillaries, ducts and nipples.

The amount and distribution of fat affects the overall size and shape of breasts. When women are younger, their breasts have less fat and are mostly comprised of glands.

The average sized breast of a pre-menopausal woman is about one-third fatty tissue. Larger breasts usually only have more fatty tissue, but not more lobular tissue. Lobular tissue, one of the two types of tissue that make up breasts, consists of groups of cells that make the breast milk. Responsible for producing milk, these milk glands expand and shrink in response to the hormone changes that accompany different stages of the menstrual cycle and pregnancy. They are mostly concentrated in the top outer portion of each breast, which is why this area can get tender and achy in the pre-menstrual phase. During pregnancy and before menstruation, the glands in the breast expand and become more sensitive.

Breasts also contain ductal tissue, which drains milk from the glands where it is made, and carries it to the nipple. After pregnancy and menopause, and as a woman continues to age, the milk glands shrink and the breast becomes mostly fat tissue in composition.

Breasts are supported by ligaments (a type of connective tissue) and skin. As breasts expand and then shrink during pregnancy and with age, the skin and ligaments that support the breasts often become stretched out, resulting in breasts responding to the call of gravity.

Inside the breast, connecting the back-side of the breast skin to the pectoral muscles, is connective tissue known as Cooper's Ligaments. These ligaments extend from the base of the chin clear down to the breast. They pull in on the skin, while the fatty tissue and the lobules press outward. There is some disagreement about the function of these ligaments, and some believe they provide the shape of the breast. It is often written that breasts sag due to the constant pulling down on the Cooper Ligaments. A pendulous look can begin to develop. Then, the delicate breast tissue begins to roll off the chest wall, over the pectoral muscle, and displaces itself under the arm and in the midriff area. This is not healthy as the proper blood flow to the breast area is now being blocked and the tissue under the arm is being bumped and battered with every move. Wearing a well fitted and properly supportive bra discourages the breast tissue from pulling on the ligaments, thereby reducing sagging and allowing for proper blood flow.

A bra that is properly fitted will accommodate the breast tissue that has been displaced back under the arm. An important function of a custom Bra Fitter is to teach a woman how to encourage that breast tissue forward, which will result in a more comfortable, healthy, and attractive bust contour.

A - Ducts

B - Lobular tissue

C - Dilated section of duct to hold milk

D - Nipple

E - Fat

F - Pectoralis major muscle

G - Chest Wall/Rib cage

Enlargement:

A -  Normal duct cells

B - Membrane

C - Lumen (center of duct)