Lymph node ultrasound is an important help for us to judge lymph nodes. Here is a brief explanation: 1. Look at the size: normal lymph nodes have 2-5mm (here refers to the short diameter), so if the short diameter of lymph nodes is less than 10mm, generally the problem is not too big. 2. Look at the structure: the structure of lymph nodes caused by inflammation and other lesions is generally normal, and the medulla, cortex and lymph node gate are clearly delineated, while in tumor lesions, the structure is often destroyed and the delineation is unclear. 3. Look at the blood flow: in lymph nodes enlarged by inflammation, the blood flow tends to be central; while in tumorous lesions, the blood flow tends to be mixed or peripheral. If the lymph node ultrasound findings reveal that the lymph nodes are relatively large or structurally disorganized, or the blood flow signal is rich and not central, then it is best to do a biopsy to rule out malignant disease.