Click to see larger diagrams of the anterior view and cross-section view of the breast. Breast cancer is a disease in which cells in the breast grow out of control. There are different kinds of breast cancer. The kind of breast cancer depends on which cells in the breast turn into cancer. Breast cancer can begin in different parts of the breast. A breast is made up of three main parts: lobules, ducts, and connective tissue.
Breast Anatomy - National Breast Cancer Foundation
Each breast has 15 to 20 sections, or lobes, that surround the nipple in a radial manner, like spokes on a wheel. Inside these lobes are smaller sections, called lobules. At the end of each lobule are tiny "bulbs" that produce milk. These structures are linked together by small tubes called ducts, which carry milk to the nipples. Fat fills the spaces between the lobes and ducts.
As you learn about breast cancer, we will repeatedly reference the anatomy of the breast. Understanding the different parts and functions will help you better grasp the details of breast cancer. The female breast is mostly made up of a collection of fat cells called adipose tissue. This tissue extends from the collarbone down to the underarm and across to the middle of the ribcage. A healthy female breast is made up of 12—20 sections called lobes.