Lymph nodes are important immune organs of the human body and are a kind of lymphatic tissue throughout the body, mainly concentrated in the neck, armpits and groin of the human body. In normal people, superficial lymph nodes are small, mostly within 0.5 cm in diameter, with smooth, soft surfaces, no adhesions to surrounding tissues, and no pressure pain. Lymph nodes are round or oval structures, mainly composed of lymphatic tissue and lymphatic sinuses, covered with a dense connective tissue perithelium, which extends into the lymph nodes, forming many intervals or trabeculae, forming a meshwork scaffold for the lymph nodes and separating the lymph node parenchyma into many parts. Lymph nodes mainly have the functions of filtering lymph, removing bacteria and foreign bodies, and producing lymphocytes and antibodies. Lymph nodes are also the most sensitive “alarms” for human diseases. Most of the lymph nodes on the surface of the body cannot be touched normally, but only when there are lesions or inflammatory reactions, they may be felt on the superficial surface of the body, so the lymph nodes reflect to a certain extent the local physical conditions of the body, such as acute and chronic inflammation caused by viral and bacterial infections, tumors, reactive hyperplasia, and antibodies. Tumors, reactive hyperplasia, and abnormal cell proliferation and metabolism can all cause swollen lymph nodes. There are many factors that can cause lymph node enlargement, which can be an inflammatory reaction, lymph node tuberculosis, or a metastatic tumor. Therefore, if you find that the lymph nodes continue to be abnormally enlarged, you must go to the hospital for systematic examination to clarify the cause and intervene early for treatment.