Overview of lymph nodes

Lymph nodes, sometimes called lymph glands, are an important part of the immune system. Lymph nodes are located throughout the body and act as filters to remove foreign objects from the fluid flowing through the lymphatic vessels.

Lymph nodes contain dense groups of white blood cells, called lymphocytes, that help neutralize foreign substances such as bacteria.

This article describes the structure and function of lymph nodes and the types and locations of lymph nodes throughout the body. It also lists different diseases, including cancer, that can affect the lymph nodes.


Lymph nodes are small, bean-shaped organs that are part of the lymphatic system. The lymphatic system is a network of blood vessels and organs that isolate and neutralize foreign substances and particles that can cause harm to the body.

In addition to lymph nodes, lymph fluid, and lymphatic vessels, this system includes the thymus, tonsils, spleen, and bone marrow.

Lymph nodes vary in size from a few millimeters to up to 2 centimeters in diameter. There are hundreds of them all over the body, but they are mostly concentrated in certain parts of the body.


Lymph nodes are small, bean-shaped organs that gather throughout the body and are interconnected with lymphatic vessels. They act as filters, helping to trap and kill foreign substances circulating in the lymph fluid.


Many of the functions of the lymph nodes are to filter and identify foreign substances that cause infection. For this purpose, lymph nodes contain two different types of white blood cells:

  • B lymphocytes (B cells) produce called antibodies that help fight bacteria, viruses, fungi, and other infectious agents
  • T lymphocytes (T cells) that initiate adaptive immune responses (ie, immune responses against infectious agents)

When foreign substances are captured and immune defenses activated, the body responds with inflammation. This can cause the lymph nodes to swell.

swollen lymph nodes lymphadenopathy, is a sign that the body is fighting an infection. Swollen lymph nodes can often be felt and seen, but not always. Some may be painful; others are not.

Not all particles filtered by lymph nodes can be neutralized. An example is cancer cells shed from nearby tumors. Although lymph nodes cannot kill cancer cells, they may be able to isolate and control them in the early stages of the disease.


The main function of lymph nodes is to fight infection by trapping bacteria, viruses and other pathogenic agents. The body then mounts an immune attack to neutralize the invader, causing the lymph nodes to swell.

Are swollen lymph nodes a sign of cancer?

type and location

Lymph nodes gather in key parts of the body.These include the armpits, neck, groin, upper abdomen and mediastinum (The area between the lungs, containing all the major organs of the chest).

Swollen lymph nodes in the armpits, neck, and groin can often be felt. Those in the mediastinum and upper abdomen may only be visible with imaging tests such as computed tomography (CT) scans or ultrasound.

The types and locations of lymph nodes vary as follows:

cervical lymph nodes

cervical lymph nodes It’s the ones on the neck. They are further broken down by location:

  • Anterior cervical lymph nodes are the lymph nodes closest to the front of the neck. These usually swell up when you have a cold or strep.
  • The lymph nodes in the back of the neck are located behind the muscular band on the side of the neck. These usually swell up when you have infectious mononucleosis.
  • The occipital lymph nodes are located at the back of the neck at the base of the skull. These usually swell with infections like HIV.

axillary lymph nodes

axillary lymph nodes are lymph nodes located in the armpit (armpit). There are usually 10 to 40 lymph nodes in the armpit.

Axillary lymph nodes are important in the diagnosis of breast cancer. When cancer cells are shed from a breast tumor, they first metastasize to the lymph nodes in the armpit. Because cancer cells tend to spread through lymph nodes in specific patterns, doctors can often tell how advanced the cancer is.

supraclavicular lymph nodes

supraclavicular lymph nodes Located above the clavicle (clavicular). Most of the time, swollen supraclavicular lymph nodes are a sign of a serious disease such as lung cancer or lymphoma (a type of blood cancer).

mediastinal lymph nodes

mediastinal lymph nodes Located in the center of the chest cavity between the two lungs. Mediastinal lymph nodes cannot be felt, but they can be seen on imaging studies such as CT scans or positron emission tomography (PET) scans.

Examination of mediastinal lymph nodes is critical for staging lung cancer and some lymphomas.

inguinal lymph nodes

inguinal lymph nodes located in the groin. Because they are responsible for filtering lymph fluid from the feet to the groin, they can swell for a variety of reasons. These include injuries, sexually transmitted diseases, skin infections, yeast infections and cancer.

retroperitoneal lymph nodes

retroperitoneal lymph nodes The back of the abdomen is located behind the tissue covering the abdominal wall. These are the nodes that testicular cancer first spreads to. They can only be seen in imaging studies.

mesenteric lymph nodes

mesenteric lymph nodes Located deep in the abdomen around the intestinal lining. These lymph nodes are usually swollen from gastroenteritis (stomach flu), but are also sometimes affected by inflammatory bowel disease (IBD) and lymphoma.

pelvic lymph nodes

Pelvic lymph nodes are located in the lower abdomen and include the hip bones, bladder, rectum, and reproductive organs. Pelvic lymph nodes can only be seen on imaging studies. Swollen pelvic lymph nodes can be a sign of bladder, prostate, cervical, ovarian, or anal cancer.


Lymph nodes are classified by their location and include:

  • Axillary lymph nodes (armpits)
  • Lymph nodes in the neck (neck)
  • Inguinal lymph nodes (groin)
  • Mediastinal lymph nodes (intrathoracic cavity)
  • Pelvic lymph nodes (in the pelvis)
  • Retroperitoneal lymph nodes (back of abdomen)
  • Supraclavicular lymph nodes (above the collarbone)

Related conditions

There are many conditions that can directly or indirectly affect lymph nodes. Some are relatively mild and treatable, while others are more severe.


Lymphadenopathy, or swollen lymph nodes, is not a disease, but a symptom of a disease. Depending on its location and characteristics, lymphadenopathy can reveal a lot about what’s going on in the body.

Lymphadenopathy can be characterized as:

  • Mobile vs. Fixed: Mobile lymph nodes are those that can be moved easily, while fixed lymph nodes are stuck to internal structures. Mobile nodes are usually benign (non-cancerous), while fixed nodes are often cancerous.
  • Pain and painless: Swollen lymph nodes are usually accompanied by infection, while cancerous lymph nodes are usually painless.
  • Local versus systemic: Enlarged regional lymph nodes that affect one part of the body, usually due to a localized infection such as strep throat. Systemic lymphadenopathy, which affects many parts of the body, can occur in conjunction with autoimmune disease, cancer, or a drug reaction.


Lymph nodes can “trap” viruses and bacteria, but are themselves susceptible to infection.

  • Lymphadenitis is the enlargement of one or more lymph nodes, usually due to infection.
  • Lymphangitis is inflammation of the lymphatic vessels, mainly due to infection, but may also involve lymph nodes

One such example is a bacterial infection in cats called cat scratch fever. The disease causes swollen lymph nodes along with fever, muscle aches and nausea that last for months.


Lymph nodes are often associated with cancer, but their role varies depending on whether a solid tumor or lymphoma is involved.

With solid tumors such as breast cancer, cancer cells often reach nearby lymph nodes before metastasizing (spreading to other parts of the body).

Solid tumor cancers are often staged based on the TNM system. The TNM system describes disease severity based on tumor size (T), the number and location of cancer lymph nodes (N), and the presence or absence of metastases (M).

With lymphoma, the cancer starts in the lymph nodes. When lymphoma spreads to other parts of the body, it is not called metastasis, but “extranodal involvement.”

Lymphomas are staged based on the number and location of lymph nodes involved, whether one or both sides of the body are involved, and whether there is extranodal involvement.


Diseases that directly or indirectly affect lymph nodes include:

  • Lymphadenopathy: swollen lymph nodes caused by the presence of an infection or disease somewhere in the body
  • Lymphadenitis: swollen lymph nodes caused by infection of the lymph nodes
  • Lymphangitis: Inflammation of the lymphatic vessels can also affect the lymph nodes
  • Cancer: Caused by cancer that has spread to or started in the lymph nodes (lymphoma)


Lymph nodes are small, bean-shaped organs that support the immune system by trapping foreign substances and killing them. The main function of lymph nodes is to fight infection. They do this by filtering bacteria, viruses, and other disease-causing agents that circulate in the lymphatic system. White blood cells called lymphocytes are then recruited to control the infection.

Lymph nodes are found throughout the body, including in the neck (neck lymph nodes), groin (inguinal lymph nodes), and armpits (axillary lymph nodes). There are also internal lymph nodes in the abdomen (mesenteric and retroperitoneal), thoracic cavity (mediastinum), and lower abdomen (pelvis).

Swollen lymph nodes (enlarged lymph nodes) can occur in response to infection or disease anywhere in the body. When the lymph nodes become infected and swollen, it is called lymphadenitis. Cancer can also affect the lymph nodes as it spreads from the tumor or starts in the lymph nodes themselves (lymphoma).

Frequently Asked Questions

  • Where are my lymph nodes?

    There are about 600 lymph nodes in the body. The main lymph node clusters are in the armpit, groin, and neck.

    understand more:

    How to find lymph nodes

  • Why are lymph nodes swollen?

    Swollen lymph nodes indicate that your body is fighting an infection. When viruses or bacteria are trapped in lymph nodes, white blood cells called lymphocytes aggressively attack. The resulting inflammation causes the lymph nodes to swell.

  • What does swollen lymph nodes feel like?

    Cancerous lymph nodes are swollen, painless, and feel elastic when pressed. They are usually fixed rather than movable.