If the lymph nodes are swollen, painful and red on the surface, they are usually caused by inflammation and infection, so it is not necessary to perform ultrasound examination. Of course, if the lymph nodes are swollen without pain, ultrasound examination is needed to determine the nature of the lymph nodes, whether they are benign lesions or caused by tumor metastasis. If it is caused by tumor metastasis, not only the lymph nodes are enlarged, but also the lymph node gate disappears and the shape of the lymph nodes changes, such as oval shape becomes round. If it is suspected that the lymph nodes are enlarged due to tumor metastasis, if necessary, the lymph nodes can be completely removed and sent for pathological examination, so that the nature of the lymph nodes can be clarified.