Swollen neck and mouth can not be opened may be due to trauma, mumps, swollen lymph nodes in the neck. 1. Trauma: As the neck and jaw are subjected to external forces such as collision and blows, the neck and jaw tissues will become swollen and painful when squeezed. Due to the swelling of the surrounding tissues, it restricts the movement of the jaw joints, resulting in the symptoms of a swollen neck and an inability to open the mouth. 2. Mumps: An acute self-limiting respiratory infection caused by mumps virus infection, which causes non-purulent swelling and pain in the parotid gland. As the parotid glands are on both sides of the jaws and close to the neck, the swelling will compress the neck tissues, which will lead to swelling of the neck and jaw joints, thus causing the neck to swell and the mouth to become inoperable. 3. Enlarged lymph nodes in the neck: when the lymph nodes in the neck are enlarged, they will squeeze the neighboring tissues and organs, and when they are pressed to the jaw joints, they will cause swelling of the jaw joints, which will make it impossible to open the mouth, and thus, the symptom of having a swollen neck and a mouth that cannot be opened will occur. It is recommended to go to the hospital in time when the neck is swollen and the mouth can not be opened, so that the diagnosis is clear and the treatment is immediate. Pay attention to the protection in the daytime to avoid injury.