Mayo Clinic Health Library

Slide show: Female breast anatomy

Updated: 10-19-2011

Female breast anatomy

Illustration showing breast anatomy

The structure of the female breast is complex — including fat and connective tissue, as well as lobes, lobules, ducts and lymph nodes.

Lobules and ducts

Illustration showing lobules, ducts and other breast structures

Each breast has a number of sections (lobules) that branch out from the nipple. Each lobule holds tiny, hollow sacs (alveoli). The lobules are linked by a network of thin tubes (ducts). If you're breast-feeding, ducts carry milk from the alveoli toward the dark area of skin in the center of the breast (areola). From the areola, the ducts join together into larger ducts ending at the nipple.

Fat, ligaments and connective tissue

Illustration showing fat, ligaments and connective tissue in the breast

Spaces around the lobules and ducts are filled with fat, ligaments and connective tissue. The amount of fat in your breasts largely determines their size. The actual milk-producing structures are nearly the same in all women. Female breast tissue is also sensitive to cyclic changes in hormone levels. Younger women might have denser and less fatty breast tissue than do older women who've gone through menopause.

Muscles

Illustration showing muscle underneath the breast

The breast has no muscle tissue. Muscles lie underneath the breasts, however, separating them from your ribs.

Arteries and capillaries

Illustration of arteries and capillaries in the breast

Oxygen and nutrients travel to breast tissue through the blood in your arteries and capillaries — thin, fragile blood vessels.

Lymph nodes and lymph ducts

Illustration of lymph nodes and lymph ducts in the breast

The lymphatic system is a network of lymph nodes and lymph ducts that helps fight infection. Lymph nodes — found under the armpit, above the collarbone, behind the breastbone and in other parts of the body — trap harmful substances that may be in the lymphatic system and safely drain them from the body.

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