Radiolucent – Refers to structures that are less dense and permit the x-ray beam to pass through them. Radiolucent structures appear dark or black in the radiographic image.
Radiopaque – Refers to structures that are dense and resist the passage of x-rays. Radiolucent structures appear light or white in a radiographic image.
Anterior nasal spine – a radiopaque V-shaped structure in the maxilla that intersects the floor of the nasal cavity and the nasal septum.
External auditory meatus – a round radiolucent passage way to the ear (bilateral).
Genial tubercle – a round/oval radiopaque structure inferior to the mandibular incisors.
Hard palate – a radiopaque bony structure that separates the nasal cavity from the oral cavity.
Internal oblique ridge – a radiopaque structure which is located on the internal surface of the mandible and proceeds downward to become the mylohyoid ridge (bilateral).
Maxillary sinus – a radiolucent area located above the apices of the maxillary premolars and molars. The floor of the maxillary sinus often appears as a thin wavy radiopaque line (bilateral).
Mandibular canal – a radiolucent tube-like structure outlined by two radiopaque lines that starts at the mandibular foramen and proceeds to the mental foramen (bilateral).
Mandibular condyle – a rounded radiopaque structure, which extends from the ramus and articulates with the glenoid fossa (bilateral).
Mental foramen – a round/oval radiolucent structure inferior to the mandibular premolars (bilateral).
Nasal septum – a radiopaque vertical bony structure that divides the nasal cavity into two.
Orbit – a radiolucent area superior to the maxillary sinus (bilateral).
Styloid process – a long, pointed radiopaque structure that extends from the temporal bone anterior to the mastoid process (bilateral).
Submandibular fossa – a radiolucent area toward the middle of the mandible that lies inferior to the mylohyoid line (bilateral).
Zygomatic process – a "J or U" shaped radiopaque structure in the maxilla that lies superior to the maxillary first molars (bilateral).
Nasopharyngeal air space – a radiolucent area that extends from the nasal cavity to the pharynx.
Glossopharyngeal air space – a radiolucent area that extends posteriorly from the tongue and oral cavity to the pharynx.
Palotoglossal air space – a radiolucent band that lies superior to the apices of the maxillary teeth and inferior to the hard palate.