Dental Radiography: Maxillary and Mandibular Anatomical Landmarks

Maxillary Radiolucent Landmarks

• Intermaxillary Suture (Incisor Region)

  Appears radiolucent (RL) with a radiopaque (RO) border. Often misinterpreted as a fracture; however, true fractures are irregular and lack a radiopaque border. Located at the midline between the two premaxillae.

• Nasal Fossa (Incisor & Canine Region)

  A pear-shaped radiolucency. Visible in the canine, incisor, and posterior regions.

• Incisive Foramen (Incisor Region)

  A radiolucency located at the midline of the palate, behind the central incisors. Differential Diagnosis: Consider an incisive canal cyst if its size exceeds 1 cm.

• Lateral Fossa (Canine Region)

  A depression appearing as a radiolucency near the canine and lateral incisor.

• Nasolacrimal Canal

  Appears radiolucent, located between the nose and eye. Visible in the canine region on periapical films and the molar region on occlusal films. Clinical Note: May be associated with bilateral runny nose.

• Maxillary Sinus (Canine Region)

  A radiolucency with a radiopaque margin, found in the molar region. Often shows divided compartments (septa) and pneumatization.

Maxillary Radiopaque Landmarks

• Anterior Nasal Spine (Incisor Region)

  Appears radiopaque, V-shaped or triangular, located at the midline.

• Inferior Nasal Concha (Incisor Region)

  A radiopaque shadow within the nasal cavity.

• Nasal Septum (Incisor Region)

  A radiopaque, vertical bony wall at the midline, dividing the nasal cavity.

• Inverted Y-Shape (Incisor & Canine Region)

  A radiopaque, inverted Y-shape in the upper canine region, formed by the floor of the maxillary sinus and the floor of the nasal fossa.

• Shadow of the Nose (Incisor Region)

  A radiopaque shadow superimposed on the roots of the incisors.

• Zygomatic Process & Bone (Malar Bone) (Molar Region)

  A U-shaped radiopacity, visible in the apical region of the first and second molars.

• Nasolabial Fold (Premolar Region)

  A radiopacity found in the canine and premolar region, due to thick cheek tissue.

• Maxillary Tuberosity (Molar Region)

  A rounded prominence posterior to the third molar, appearing as a radiopaque bulge.

• Pterygoid Plates (Molar Region)

  Medial and lateral plates posterior to the maxillary tuberosity, located between the hamular notch.

• Coronoid Process of the Mandible (Molar Region)

  A radiopaque shadow appearing as a triangle at the angle of the film. In the maxillary molar region, it appears as a triangular radiopacity.

Mandibular Radiolucent Landmarks

• Symphysis Menti (Incisor Region)

  Appears radiolucent in infants, located at the midline of the jaw. Fuses by the end of the first year.

• Mental Fossa (Incisor Region)

  A radiolucent depression on the labial aspect of the mandible.

• Lingual Foramen (Incisor Region)

  A radiolucency surrounded by a radiopaque ring (formed by the genial tubercles). It marks the termination of the incisive branch of the mandibular canal.

• Mental Foramen (Premolar & Canine Region)

  The anterior limit of the inferior alveolar canal. It may not appear on X-rays if the opening is located superiorly and posteriorly, not in the direct path of the rays. Typically found in the region of the lower fifth tooth (premolar).

• Mandibular Canal (Premolar & Molar Region)

  Appears radiolucent, a dark linear shadow (tube-like) with two thin radiopaque borders.

• Nutrient Canals

  Visible in approximately 5% of patients, typically in the lower anterior region. Associated with high blood pressure, periodontal disease, Black males, and severe alveolar bone loss.

• Submandibular Gland Fossa (Premolar & Molar Region)

  A radiolucent fossa on the lingual surface, below the mylohyoid ridge.