Dental Anatomy Quiz on Radiographs

Radiographic Anatomy of the Head, Neck, and Face

• Radiographs display varying shades of gray, with dark areas being radiolucent (low density, allowing radiation to pass through) and light areas being radiopaque (high density, blocking radiation).
• Examples of radiolucent structures include periodontal ligaments and pulpal tissues.
• Examples of radiopaque structures include dentin, enamel, bone, metal, and resin restorations.

Maxilla

• Composed of two bones joined at the midline by the maxillary suture.
• Houses the upper teeth within the alveolar process.
• Appears radiopaque on radiographs.

Mandible

• A single, movable bone of the lower jaw.
• Consists of the condyloid process, coronoid process, ramus, body, alveolar process, and mental protuberance.
• Houses the lower teeth within the alveolar process.
• Appears radiopaque on radiographs.

Body of the Mandible

• The horizontal portion of the mandible, extending between the rami.
• Appears radiopaque.

Ramus

• The vertical portion of the mandible, perpendicular to the body.
• Plural is rami.
• Appears radiopaque.

Condyle of the Mandible

• Ball-like structure forming the temporomandibular joint.
• Part of the TMJ.
• Appears radiopaque on radiographs, cephalometric images, and CT scans.

Orbit

• Eye cavity.
• Appears radiolucent.

Midsagittal Plane/Midline

• Imaginary vertical plane dividing the body into equal halves.

Francfort Plane

• Imaginary line from the eye socket to the auditory meatus.

Internal Landmarks (Head, Neck, Face)

• Some internal anatomical features visible on radiographs include the lateral venous sinus, frontal sinus, ethmoid sinus, mastoid air cells, sphenoid sinus, frontozygomatic suture, and pharyngeal airspace.
• These typically aren't seen on intraoral images, but may show on extraoral images.

Airspaces (Panoramic Images)

• Panoramic images can show airspaces outlined within the oral cavity.
  • Glossopharyngeal airspace
  • Palatoglossal airspace
  • Nasopharyngeal airspace
  • Oral orifice airspace
  • Uvula
  • Nares airspace

Inverted Y

• A radiopaque area at the junction of the nasal fossa (cavity) and maxillary sinus, above the maxillary canines.

Maxillary Sinus

• Air-filled cavities above the maxillary premolars and molars.
• Appear radiolucent; Dense tissue of the sinus floor appears radiopaque.
• Roots of maxillary molars often appear to penetrate the sinus, but rarely do.

Nutrient Canals

• Small channels through bone, containing blood vessels, nerves, and lymph tissue to supply the teeth.
• Appear as vertical radiolucent lines on periapical images.

Internal Oblique Ridge

• Prominent bone on the internal aspect of the mandible, near molar apices, extending down and forward to the molar region or mylohyoid ridge.
• Radiopaque band, possibly superimposed on the external oblique ridge.

Mandibular Canal

• Passageway through the mandible containing the inferior alveolar nerve and blood vessels.
• Enters through the mandibular foramen and exits via the mental foramen.
• Appears as a radiolucent band bordered by radiopaque lines (cortical bone).

Cortical Bone

• Dense bone forming the outer layers of the maxilla and mandible.

Zygoma (Cheekbone)

• Appears as a radiopaque band on maxillary posterior periapical radiographs.

Coronoid Process

• Prominent bone anterior to the ramus of the mandible; sometimes superimposed on the maxillary tuberosity.
• Appears as a radiopaque triangle.

Zygomatic Process of the Maxilla

• Part of the cheekbone, located above the maxillary molars, and anterior to the zygoma.
• Appears as a J or U-shaped radiopaque structure.

Maxillary Tuberosity

• Round prominence posterior to the maxillary molars, allowing blood vessels and nerve entrance.
• Appears radiopaque.

External Oblique Ridge/Line

• Prominent bone on the external aspect of the mandible, extending from the ramus to third molar roots.
• Appears as a radiopaque band near mandibular molar crowns.

Mental Foramen

• Two openings on the external mandible through which blood vessels and nerves pass.
• Located near apical premolars.
• Appear as small, round radiolucent areas.

Mental Process/Ridge

• Prominent bone on the external anterior mandible, extending to the premolar region.
• Appears as a thick, radiopaque band (or inverted V).

Alveolar Process

• Upper aspect of the mandible, appearing radiopaque.

Alveolar Ridge

• Bony ridge containing tooth sockets, appearing radiopaque.

Nasal Fossa (Cavity)

• Two bone depressions above the maxilla, divided by the nasal septum.
• Appear as radiolucent spaces above maxillary incisors roots.

Mental Fossa

• Depressed area of bone on the external mandible.
• Appears radiolucent above the mental ridge.

Lateral/Canine Fossa

• Slightly concave area below and between maxillary lateral incisors and canines.
• Appears radiolucent.

Anterior Nasal Spine

• Triangular projection from the nasal floor.
• Appears as a V-shaped radiopaque area in maxillary incisor region.

Nasal Septum

• Bone dividing the nasal fossae.
• Vomer bone (visible portion) appears as a radiopaque band.

Median Palatal Suture

• Fusion line between palatine processes of the maxilla.
• Appears as a radiolucent vertical line.

Mylohyoid Ridge

• Prominent internal mandibular bone extending from the lower border.
• Appears as a radiopaque band, potentially superimposed on mandibular roots.

Submandibular Fossa

• Depression on the lingual mandible housing salivary glands.
• Appears as a large radiolucent area below mandibular molars.

Genial Tubercles

• Small, donut-shaped bone spines near the lingual foramen.
• Appear radiopaque.

Lingual Foramen

• Midline opening on the internal mandible.
• Small radiolucent dot in the middle of the genial tubercles' radiopaque ring.

Incisive Foramen

• Pear-shaped opening in the anterior hard palate.
• Allows nasopalatine nerve and vessels exit from the maxilla.
• Appears radiolucent.

Hamulus/Hamular Process

• Small, hook-shaped bone from the sphenoid bone, behind maxillary tuberosity.
• Appears radiopaque.

Full Mouth Series Breakdown (detailed left to right)

• Provides detailed locations of teeth and associated structures.
  • Maxillary and mandibular molars, premolars, and incisors are noted.
  • Bitewings are identified with the corresponding tooth positions.
  • Important anatomical landmarks such as sinuses, orbital structures, mental foramen are identified.
  • Images should clearly show proximal contacts (interproximal areas).