Where Are the Lymph Nodes Located?

Overview
Most people are only aware of the lymph system when they have a swollen gland somewhere. In fact, lymph glands are present throughout the body and play an important role in immunity and other bodily functions. Lymph nodes are just one part of an amazing body system--the lymph system--that rivals the circulatory system in importance.

Significance
The lymph system's best known function is to protect the body from viruses, bacteria, fungi and other infectious organisms. It is also responsible for making sure that fats and vitamins are absorbed from the intestine. The lymph system acts like the body's sponge. Leakage of fluid from tissues and the bloodstream occurs all the time, and the lymph system mops up this fluid and returns it to circulation.

Function
Like the circulatory system, the lymph system transports a fluid, called lymph fluid. Lymph fluid is clear and consists mostly of blood plasma, plus a few red and white blood cells and a fluid called chyle, which is drained from the intestines and contains protein and fat. The lymph system works together with the circulatory system to help transport nutrients to cells and waste products away from cells.
In addition to lymph fluid, the lymph system also includes organs with immune functions, such as the bone marrow, lymph nodes, spleen, tonsils, adenoids and thymus gland, which is located in the neck. The bone marrow produces immune cells called lymphocytes.

Types
Wherever there are lymph channels, there are lymph nodes, which are oval-shaped structures packed with several different types of immune cells. It is the job of the lymph nodes to filter the lymph fluid before it is returned to the general circulation. Even though lymph nodes are present nearly everywhere (except the brain), they are heavily clustered in the groin, armpits and neck.

Size
Under normal circumstances, lymph nodes are so small that they cannot be felt. When a lymph node swells to about 1 cm in diameter, you can usually feel it if you press on it. That's why your doctor feels under your jawline when you have a sore throat or ear infection; she is checking for swollen lymph nodes. These so-called swollen glands may develop as the result of infection. The nodes trap the invading organisms, which causes them to become enlarged. Swollen nodes can also be caused by cancer in nearby tissue.

Identification
The cervical lymph nodes are located on the neck and face. Specifically, there are groups behind, below and straight down from the ear, on the lower neck stretching over toward the front of the shoulder, along the lower jaw and in a line diagonally up from the ear lobe. All told, there may be as many as 300 nodes in this region. The axillary lymph nodes are clustered in the armpit. The inguinal lymph nodes are located in the groin. Some are close to the surface, and others are deeper. There are fewer axillary and inguinal nodes than cervical ones.

Warning
The fact that a gland is swollen does not reveal anything about why it might be swollen. It could be caused by an infection. Common infectious causes of swollen lymph nodes include tonsillitis, mouth infections, gum infections, ear infections and abscesses. Cancer may also cause swollen glads. If the cancer cells are drained away from the tumor, they may lodge in a nearby lymph node. The lymph system can also develop its own type of cancer, such as Hodgkin's disease and various types of lymphoma. HIV disease and immune disorders like rheumatoid arthritis can cause lymph swelling.
Go to your doctor if your swollen glands do not shrink within a few weeks after you first notice them or if they continue to grow. A gland that is red and swollen may need medical treatment. Fever and night sweats in a person who has swollen glands could suggest a lymphoma. Hard, swollen lymph nodes may also need prompt medical attention. A node that grows quickly is more likely to be the result of an infection. One that grows slowly may suggest cancer, especially if it doesn't hurt. But don't drive yourself crazy with what-ifs and self-diagnosis. See a doctor.

Resources
Breastcancer.org
Loyal University Medical Education Network
Medcyclopaedia
MedlinePlus