- The breasts are made up of fat, connective tissue and gland tissue divided into lobes. The lobes are drained by tubes called ducts which spread form the lobes towards the nipple.
- Younger women have denser breast as they have more glandular tissue rather than fat in their breasts. Glandular tissue is gradually replaced by less dense fat after menopause.
- Close to the breast there is a network of lymph nodes which are part of the lymphatic system. They contain a yellow fluid which collects waste products and drains into veins for it to be removed. Lymph glands are located throughout the body. Lymph nodes found in the armpit are the axillary lymph glands. When cancer cells are released from the breast tissue it can travel to the lymph node causing them to increase in size.