The main causes of clavicular lymph node enlargement include lymphadenitis, lymphatic tuberculosis, tumor metastasis, etc. 1. Lymphadenitis: Because the neck is rich in lymph nodes, it is a common site of bacterial invasion, therefore, lymphadenitis in the neck, upper limbs and shoulders is a common cause of clavicular lymph node enlargement. Patients suffering from clavicular lymph node swelling are often accompanied by pain, localized swelling and other phenomena. 2. Lymphatic tuberculosis: The swollen lymph nodes in the clavicle are also difficult to be the cause of lymphatic tuberculosis. Mycobacterium tuberculosis can spread to the lymph nodes in the neck through the bloodstream and cause lymphatic tuberculosis, which leads to swollen lymph nodes in the clavicle. It is usually accompanied by hot flashes, fatigue, night sweats and other symptoms. 3. Tumor metastasis: the cause of enlarged lymph nodes in the clavicle may also be caused by tumor metastasis. It is mostly seen in the surface lymph node metastasis of some malignant tumors, such as lung cancer, breast cancer, gastric cancer, etc., which can be drained to the supraclavicular lymph nodes through thoracic ducts, leading to lymph node enlargement. If patients have enlarged lymph nodes in clavicle, they should go to regular hospitals in time to find out the cause of the disease and actively cooperate with doctors for treatment, so as to avoid delaying the condition.