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Understanding the Breast

Your breasts lie on your pectoral, or chest, muscles, and are made up primarily of fat and glandular tissues, together with nerves, blood vessels, and connective tissue.

Women’s breasts contain 15 to 20 lobes, which radiate outward along branching tubes, called ducts, from the nipple. Each lobe is composed of many small lobules that end in tiny bulb-shaped mammary glands that can produce milk. The ducts link the lobes, lobules, and bulbs together to transport milk to the nipple.

Breasts also contain lymph vessels that carry the colorless fluid known as lymph to the small kidney-bean-shaped organs called the lymph nodes. There are 400 to 500 lymph nodes throughout the human body, including clusters of them in the armpit, above the collarbone, and in the chest. These lymph nodes filter bacteria, other toxic substances, and cancer cells out of the lymph that drains out of the breast area.

Men’s breasts are similar to women’s, except they typically contain far fewer, if any, milk-producing glands. They do, however, have ducts, although they are much less developed.

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