Lymph nodes can be detected by physical examination or imaging. 1. Physical examination: Lymph nodes are mainly detected by visualization and palpation. Visual examination can detect lymph nodes with large diameter, obvious protrusion or skin breakdown. Palpation is more sensitive than visual examination in detecting lymph nodes, and can roughly determine the size, hardness, mobility, pressure and pain, and the connection with the surrounding tissues of lymph nodes. 2. Imaging examination: Imaging examination can be done by ultrasound, CT, magnetic resonance and so on. Imaging examination is more sensitive and accurate than physical examination, and can indicate the specific diameter and size of lymph nodes and their relationship with the surrounding tissues, etc. It is important for the diagnosis of lymph nodes. It is important for the diagnosis of lymph nodes.