This is a compound word. First of all, it is called the oral cavity, which means that it is inside the mouth. The jaw is divided into the upper jaw and the lower jaw. The upper jaw is the bone plate between the nasal cavity and the oral cavity, and the lower jaw is commonly known as the chin. .When combined, the oral and maxillofacial surfaces refer to the upper and lower sides of the mouth, that is, the two sides where teeth grow. There are only the upper and lower jaws