The maxillae are two large facial bones one on each side of the face that contain the upper teeth and form the upper jaw. Maxilla bones spread below the orbits the bony cavities in the skull where the eyeballs sit and above the jawbone. Each maxilla is hollow and contains a large maxillary sinus an air cavity that pumps mucous uphill to the main sinus opening. The bones that make up the maxilla are the ethmoid frontal and zygomatic (cheek) bones. The maxilla also forms much of the lateral walls of the nasal cavity the floor of the orbital cavity and part of the cheek.
The maxilla contains the alveolar process which forms a firm foundation that holds the top row of teeth such that the lower teeth or mandibular teeth can move against them. This movement is how chewing occurs.
The outer wings of the maxilla are called zygomatic processes. These appear at the point where the maxilla meets the zygomatic (cheek) bones forming the cheek arches. The upper part of the maxilla is called the orbital surface. It forms the lower inner surface of the orbit cavity. The exterior surface of the maxilla is called the frontal process. It lies just between the orbit and the nasal cavity. The maxilla attaches to the palatine bone the bone forming the roof of the mouth just behind the teeth.