The parts of the breast that are visible are the breast tissue, nipple, and areola. On the inside, there are lobules (milk producing glands), ducts (milk passages that connect the lobules and the nipple), and stroma (fatty tissue and ligaments surrounding the ducts and lobules, blood vessels, and lymphatic vessels).
Axillary lymph nodes are located under the arm, near each breast. Lymph nodes are small masses of tissue that are part of the body’s immune system. Lymph nodes filter a fluid called lymph. Lymph nodes attack bacteria, viruses, and other foreign substances that enter the body. These lymph nodes, however, are susceptible to infections and cancer.