The anatomy of the breast is somewhat complex: the breast sits on the chest muscles and is made up of lobes, lobules, and ducts. The lymph vessels in each breast lead to the lymph nodes found near the breast in the axilla, above the collar bone, and in the chest.
The breasts sit on the chest muscles, which cover the ribs. The breast itself is made up of lobes and ducts.
Each breast has 15 to 20 sections called lobes, which have many smaller sections called lobules. Lobules end in dozens of tiny bulbs that can produce milk. The lobes, lobules, and bulbs are linked by thin tubes called ducts.
Milk flows from the lobules through these ducts to the nipple. The nipple is in the center of a dark area of skin called the areola. Fat fills the spaces between the lobules and the ducts.
Each breast also contains blood vessels and lymph vessels. The lymph vessels carry an almost colorless fluid called lymph. Lymph vessels lead to organs called lymph nodes. Lymph nodes are small bean-shaped structures that are found throughout the body. They filter substances in lymph and help fight infection and disease. Clusters of lymph nodes are found near the breast in the axilla (under the arm), above the collarbone, and in the chest. Together, the lymph vessels and lymph nodes make up the lymphatic system, which circulates lymph throughout the body. Lymph contains cells that help fight infection and disease.