The zygoma appears as a U-shaped radiopaque line with the round portion superimposing the area of the first and second molars. Depending on the angle in which the x-ray beam passes through the zygoma, it will vary in size, width, and definition. The nasolabial fold may appear as an oblique line traversing the premolar region. The line of contrast is well-defined and the area of increased radiopacity is caused by the superimposition of the cheek tissue. This feature increases with age and can be used to identify the side of the maxilla if the area is edentulous.
Typical appearance is a single radiopaque shadow with no trabecular pattern.
The hamulus may be seen extending inferiorly from the medial pterygoid plate and does show trabecular pattern. Normal Mandibular Radiographic Anatomy On periapical radiographs of the central incisors the mental fossa appears as a radiolucent depression extending laterally from the midline and between the alveolar ridge and the mental ridge. Due to the thinness of the bone in the area, the mental fossa appears slightly radiolucent compared to adjacent bone and may be mistaken for periapical disease. Typically it is positioned halfway between the lower border of the mandible and the alveolar crest, in the region of the apex of the second premolar. It may appear over the apex of a tooth, mimicking periapical pathoses.