Lymph nodes are found in all parts of the human body, including the head, neck, armpits, chest, inside the chest, inside the abdomen, inguinal region, lower limbs, and ankles. Generally, lymph nodes cannot be touched on the surface of the body, but they can be touched behind the ear because of the thin subcutaneous fat, and in the groin area because of the large size of the lymph nodes, which can usually be touched when lying flat on the bed. If the lymph nodes appear swollen and accompanied by painful lymph nodes, it is mostly caused by bacterial infection, and different antibiotics should be used according to the bacteria of infection. If painless lymph node enlargement occurs, it should be considered to be caused by tumor metastasis, which may be thyroid cancer metastasis to the neck or breast cancer metastasis to the armpit, further examination is needed, and radical tumor treatment is required after diagnosis.