Lymph nodes are the organs responsible for the functioning of immune system. They are located in groups mostly in the neck, armpit, collarbone, and groin. In this article, we will discuss the location and function of this immune system organ.
Lymph nodes are small, bean-shaped organs of the lymphatic system. The lymphatic system circulates the interstitial fluid called lymph to the body cells and tissues. It also collects waste substances from the bloodstream. Lymph contains white blood cells (WBCs) as its major component. It is more or less similar to the blood plasma. Lymph nodes, on the other hand, are made up of various types of cells and tissues, of which WBCs and lymphoid tissues are more abundant.
Location of Lymph Nodes
The size of lymph glands in adults is smaller, as compared to those in children between the age group 10 – 12. Lymph node is located in the lymphatic system, which is distributed throughout the body. It can be present independently or in groups. About 500 – 600 lymph nodes are present in the human body. Groups of lymph nodes are present in the neck, collarbone, under the arms (armpit), and groin. Following is the list of lymph nodes with their placement in the body.
Cervical lymph nodes
These lymph nodes are located in the head and neck region. Basically found deep in the neck, behind the ears and bottom of the jaw. In total, they are six in number. They draw lymph from the scalp, face, nasal cavity and pharynx.
Supraclavicular lymph nodes
Situated along the collarbone or clavicle, they drain lymph from the parts of the collarbone and the upper parts of the chest. These nodes can also be considered a part of the cervical lymph nodes.
Axillary lymph nodes
These nodes are present in the armpit area. They are divided into two types, namely, superficial and deep lymph nodes. They drain lymph from arm, walls of thorax and breast.
Mediastinal lymph nodes
They are present in the central part of the chest, between the lungs. It drains from the middle section of chest cavity, parts of the upper abdomen and lungs.
Supratrochlear lymph nodes
These nodes are present on the arms just above the elbow joint. They drain from the fingers, hand on the ulnar side of the arm and superficial areas of the forearm.
Mesenteric lymph nodes
Distributed in the lower abdomen, they lie close to the small intestine. They drain cecum, jejunum, ileum, colon and upper part of rectum.
Inguinal lymph nodes
These nodes are located in the groin area. They may be superficial or deep lymph nodes. They receive lymph from the genital areas, buttock, anus, abdominal wall and legs.
Femoral lymph nodes
Located in the upper thigh portion along the femoral veins. They are immediately below the inguinal lymph nodes. They drain from some of the genital parts, buttock, thigh and the medial side of the leg.
Popliteal lymph nodes
These lymph nodes are present in the knee area called popliteal fossa. There are two sets of popliteal lymph nodes some are present beneath the popliteal fascia and some are found between the popliteal artery and the posterior surface of the knee joint. They drain from the knee, thigh, calf and feet.
Functions of Lymph Nodes
As already mentioned, lymph nodes are essential organs of the immune system and play a crucial role in the normal functioning of the system. Here are the major functions of lymph nodes:
Lymph Collection and Filtration
Lymph is drained and collected from the adjoining parts of the lymph nodes. To be more precise, the afferent lymphatic vessels deliver unfiltered body fluid to the lymph node for filtration. These nodes act as filters for disease-causing agents like bacteria, viruses, and other microorganisms. The foreign particles or the disease causing agents collected in the lymph nodes are then destroyed by the WBCs. The filtered fluid is collected by the efferent lymphatic vessel, which is then emptied into the cardiovascular system.
Production of Antibodies
According to medical studies, lymph nodes are the major sites for initiation of autoimmune responses. Lymph nodes contain lymphocytes, which is a type of WBC. At the time of infection, in response to the antigen, lymphocytes make antibodies which target the pathogens and destroy them. Due to this activity, there is an increase in the production of beta cells which results in swollen, inflamed, painful and sensitive nodes. Significant change in their size can be observed during mild infection like cold and life-threatening condition like cancer.
Many a time, biopsy is conducted in order to diagnose a swollen or inflamed lymph node. The pathophysiology of breast cancer reveals that the disease spreads from the breast to the lymph nodes located in the armpit. Considering this, analyzing the presence of cancer in the axillary lymph nodes serves as a basic technique to identify the stage of breast cancer. If required, the concerned physician will prescribe medications based on the current status of the lymph nodes.
Hence, we can say that the size of a lymph node plays a very important role in determining various medical conditions. This is the reason why a health care specialist checks for any swollen nodes in the major locations such as neck, armpit, collarbone, and groin during physical examination. Though swelling and inflammation of the lymph nodes is a part of autoimmune response and it subsides on its own, if the swelling lasts for more than two weeks, consult your doctor immediately.