Breast

Each breast has 6-9 overlapping sections called lobes. Each lobe comprises many smaller lobules, which ends in dozens of tiny bulbs that can produce milk. Thin tubes, called ducts, link all the lobes, lobules, and bulbs. These ducts lead to the nipple in the centre of a dark area of skin called the areola. Fat fills the spaces around the lobules and ducts. There are no muscles in the breast, but muscles lie under each breast and cover the ribs.

Each breast contains blood vessels and vessels that carry colourless fluid called lymph. The lymph vessels lead to small bean-shaped structures called lymph nodes. Clusters of lymph nodes are found in the axilla (under the arm), above the collarbone and in the chest. Lymph nodes are also found in many other parts of the body.