Table of Contents
Key Takeaway
Bootcamp.com’s Normal Radiographic Anatomy for the INBDE
Understanding what normal radiographic anatomy is important in order to be able to identify when a radiographic finding is abnormal.
Tooth Anatomy

We can zoom in and see some additional structures:

Additional landmarks:

Some additional pulp features:

In some radiographs, the gingiva can be visible. This will appear as:

Additional supporting structures include cancellous/trabecular bone and cortical bone:

Maxillary Region
There are several other anatomic features that can be recognized in maxillary periapicals.
Intermaxillary suture
- Linear or slightly undulating radiolucent line between maxillary central incisors


Lateral fossa
- Diffuse radiolucent region apical and overlying maxillary lateral incisor


Canine fossa
- Diffuse radiolucent region distal to the maxillary canine


Anterior nasal spine
- diffuse , v-shaped radiopaque region apical to maxillary central incisors


Incisive foramen
- Oval radiolucency in region of maxillary central incisors


Nasopalatine canal
- Radiolucent channel between maxillary central incisors


Nasal septum
- Vertical radiopaque line at midline superior to central incisor


Nose
- Outline of soft tissue


Nasolabial fold
- Outline of soft tissue


Zygomatic arch
- Broad, radiopacity projected mostly superior and posterior to maxillary molars


Zygomatic process of maxilla
- U-shaped, radiopaque line in region of maxillary molars


Floor of maxillary sinus
- Bottom portion of the pyramidal-shaped cavity above the roots of the maxillary premolars and molars


- The nasal cavity and sinuses can have many variations
- The nasal cavity and sinus can be normal, not visible, or large
- The paranasal sinuses can vary in size, shape, and internal septations
- The sinuses have many variants related to their outline, shape, and internal appearance
- The size of the maxillary sinus increases as an individual ages until skeletal maturity is gained
This characteristic “Y” shape is commonly tested!


Maxillary tuberosity
- Radiopaque, rounded prominence distal to maxillary molars


Hamulus
- Hook-like, radiopaque process projected posterior to maxillary tuberosity


Mandibular Region
Periapical radiographs in the mandibular posterior region can include anatomic features of the mandible.

Genial tubercles
- Poorly defined, irregular, radiopaque region apical to mandibular central incisors


Mental ridge
- Radiopaque, triangular shaped area below the mandibular anterior teeth


Mental foramen
- Round or oval radiolucency in apical region of mandibular premolars or first molars


- Variant of normal: two on one side or posteriorly positioned (this could be real or tube angulation)
Submandibular gland fossa
- Poorly defined, broad radiolucency apical to mandibular molars and premolars


Inferior Alveolar Canal
- Curvilinear, radiolucent channel in posterior mandible


- Variant of normal: anterior looping (shown below), multiple canals, canal diameter large or small


Mental fossa
- Poorly defined, broad, radiolucent region superimposed on mandibular incisor roots


Nutrient canals
- Radiolucent lines extending between tooth roots


Lingual Foramen
- Round, radiolucent point apical to mandibular central incisors

Sialolith
- Round or oval-shaped radiopacity located on the inside of the mandible
- Due to the calcification and formation of stones in the major salivary glands

Mandibular tori
- Broad radiopacity overlaying the roots of posterior mandibular teeth


Cervical burnout
- This term refers to the radiolucency found just below the CEJ on the root due to anatomical variation or a gap between the enamel and bone covering the root
- It can appear similarly to caries


Sinus pneumatization
- The continuous physiological process that causes the paranasal sinuses to increase in volume
- Although it it seems like there is pathology between the roots of tooth 3 and 5, it is just the expanded sinus


Panoramic Features
There are several common anatomic features recognizable in the panoramic radiograph.


- Mandibular ramus- Broad radiopaque region in the mandible that connects the body to the condyle and coronoid process
- Mandibular angle- Junction of the posterior and inferior border of the mandibular ramus
- Condyle- Oval radiopaque process that extends posteriorly and superiorly from the mandibular ramus
- Coronoid process- Triangular radiopaque process that extends anterior and superiorly from the ramus
- Sigmoid notch- Concavity between the condyle and coronoid process
- Antegonial notch- Concavity on inferior border of the mandible
- Cervical spine- Irregular, radiopaque column behind the mandible and maxilla
- Hyoid- Radiopaque process inferior or even superimposed onto the mandible
- External auditory meatus- Radiolucent oval behind the mandibular condyle
- Styloid process- Pointed radiopacity behind the mandibular ramus
- Glenoid fossa- Thin radiopaque concavity where the condyle meets
- Articular eminence- Radiopaque convexity in front of the glenoid fossa
Soft tissue features can also superimpose onto the panoramic radiograph.


- Tongue- Creates an arch that superimposes over the mandibular teeth and portions of the maxillary teeth
- Soft palate- Creates an arch that superimposes above the tongue
- Epiglottis- Radiopaque structure seem behind the tongue
- Oropharynx- Creates a column of soft tissue that superimposes behind the mandible
- Nasopharynx- Creates a column of soft tissue that superimposes behind the mandible and is located above the oropharynx