Lymph nodes are small, bean-shaped glands that are a vital part of the body’s lymphatic system. This network of vessels, tissues, and organs maintains fluid balance and protects against infection. They act as filtering stations, playing a significant role in immune defense.
Locating Armpit Lymph Nodes
The armpit, also known as the axilla, is home to a cluster of lymph nodes, typically numbering between 20 and 49. These axillary lymph nodes are situated deep within the armpit’s fatty tissue, not superficially on the skin’s surface.
When healthy, these nodes are generally small, less than 1 to 2 centimeters in diameter, and oval-shaped. They feel soft and pliable, making them difficult to feel under normal circumstances. Their deep location and soft texture contribute to them usually going unnoticed.
Their Role in Health
The lymph nodes in the armpit are crucial centers for immune activity. They receive and filter lymph fluid, a clear liquid containing white blood cells, from the entire upper limb, chest wall, upper abdominal wall above the navel, and a significant portion of the breast.
Within these nodes, specialized immune cells, such as lymphocytes (B and T cells) and macrophages, are present. As lymph fluid passes through, these cells trap and remove harmful substances like bacteria, viruses, and abnormal cells, including cancer cells. The nodes also activate immune cells to mount a targeted response against detected threats.
What Swollen Lymph Nodes Mean
When armpit lymph nodes enlarge, a condition known as axillary lymphadenopathy, it typically indicates an active response. This swelling occurs as the nodes filter unwanted substances or produce more immune cells to fight an infection or disease. The enlargement can make them noticeable as a lump under the arm.
Common causes for swollen armpit lymph nodes include infections affecting the arm, hand, or chest, such as cellulitis. Viral infections like the flu or mononucleosis can also cause swelling. Recent vaccinations can temporarily enlarge lymph nodes as the immune system responds.
Less common, but more serious, reasons for axillary lymph node swelling include certain types of cancer, such as breast cancer that has spread, or lymphomas. While most instances of swollen lymph nodes are benign, consult a healthcare provider if the swelling persists for more than two to four weeks, continues to grow, feels hard or rubbery, or is accompanied by other symptoms like fever, unexplained weight loss, or night sweats.