Very small organs of the lymphatic system. Lymph nodes are located in many areas of the body, mainly in the neck, under the arms, and in the groin. Lymph nodes play a crucial role in the immune system. When lymph is filtered through the lymph nodes, foreign substances are trapped and destroyed by the lymphocytes that line the walls of the lymph nodes. (Clinicalinfo Glossary. 2025. Lymph nodes. https://clinicalinfo.hiv.gov/en/glossary/lymph-nodes)
Lymphadenitis refers to lymphadenopathies that are due to inflammatory processes. It is characterized not only by nodal swelling, but also by pain, skin changes, fever, edema, and/or purulent collections. (Gosche JR, Vick L. Acute, subacute, and chronic cervical lymphadenitis in children. Semin Pediatr Surg. 2006 May;15(2):99-106. doi: 10.1053/j.sempedsurg.2006.02.007. PMID: 16616313; PMCID: PMC7111159.)