Lymph nodes (also called lymph glands) are small oval structures scattered all over the body. Lymph nodes contain lymph cells (called lymphocytes). Lymphocytes grow and mature inside a lymph node. These cells are a type of white blood cell (WBC) that helps the body fight against infections. Lymph nodes are a part of the lymph system of the body. (See the article on the Lymph System).
Lymph nodes are connected to each other by lymph channels called the lymphatics –- small tubes (like blood vessels)-– through which lymph nodes as well as proteins and other substances move from one part of the body to another.
Lymph nodes in different parts of the body are named differently
- Cervical lymph nodes – lymph nodes in the neck
- Axillary lymph nodes – lymph nodes in the armpits
- Mediastinal lymph nodes – nodes inside the chest
- Inguinal lymph nodes – those in the groin
- Retroperitoneal and Mesenteric lymph nodes – lymph nodes in different parts of the abdomen.
- Pelvic lymph nodes – nodes in the pelvis.
When lymph nodes increase in size, they are called enlarged lymph nodes. When enlarged nodes can be felt by the doctor (in areas like the neck, armpits and groin) they are called palpable lymph nodes.
Lymph nodes can increase in size in a number of conditions. Infections, cancer and many immune diseases can affect lymph cells and cause an enlargement of lymph nodes. Enlarged lymph nodes are often the first sign of lymphoma, a cancer of lymph cells. But all enlarged nodes are not lymphoma. (See the article Are Enlarged Lymph Nodes Always a Lymphoma?). Any enlarged node should be brought to the notice of a physician and investigated for the correct diagnosis.