Zygomatic zygomatic arch fracture is a fracture that occurs in the zygoma and zygomatic arch (in the lower lateral part of the orbit to before the ear screen), which may be caused by traffic accidents, sports, work injuries and so on. Common clinical symptoms after the fracture include facial asymmetry, zygomatic bone depression, localized pain and subcutaneous bruising. In addition, some patients also have the symptom of not being able to open their mouths. Some patients ask: zygomatic arch is far away from the jaw, why the fracture of zygomatic bone and zygomatic arch can cause jaw movement disorder? To answer this question, we first need to understand how the mandible moves when opening the mouth. There are two anatomical structures on the posterior border of the mandible that are closely related to the opening of the mouth, which are the “condyle” (put your finger in front of the ear, and feel the condyle rotating when you open your mouth) and the “rostral protuberance” (in front of the condyle, the position of the condyle is medial, which is hard to reach on the surface of the body). ). The condyle is the center of rotation of the mandible during mouth opening movements, while the rostral process moves downward from the medial aspect of the zygomatic arch. When a zygomatico-zygomatic arch fracture occurs, the fracture fragment may want to displace the zygomatic arch medially, limiting the movement of the rostral process. The patient may then show symptoms of limited mouth opening. If the zygomaticozygomatic arch fracture is immediately repositioned, the fracture may heal inappropriately or the rostral process may be scarred with the surrounding tissues, resulting in uncorrectable mouth opening restriction. Therefore, we would like to remind the patients not to think that the change in the shape of the fracture can be “tolerated” or “it doesn’t matter if it is ugly”. If the fracture is not treated in time in a regular hospital, severe mouth opening restriction may occur, and the difficulty of treatment will also increase.