Intra-Oral Radiography Anatomy

Question 1

What is pictured here?

Answer 1

Cervical Burnout

Caused by the overexposure of the lateral portion of the roots between the enamel and the alveolar crest and results in an ill-defined radiolucent zone (arrows)

Question 2

What is pictured here?

Answer 2

Root Canal – Apical Third

Although the root canal is typically not radiographically visible in the apical 2mm of a tooth, anatomically it is present & contains the vascular and neural supply to the pulp (arrow)

Question 3

What is pictured here?

Answer 3

Developing Tooth

A developing root shown by a divergent apex around the dental papilla (arrow) which is enclosed by an opaque bony crypt.

The apices of the first molar are still open but nearing closure.

Question 4

What is pictured here?

Answer 4

Periodontal Ligament space

The periodontal ligament space (arrows) is seen as a narrow radiolucency between the tooth root and the lamina dura

Question 5

What is pictured here?

Answer 5

Lamina dura

The lamina dura (arrows) appears as a thin opaque layer of bone around teeth (A) and around a recent extraction socket (B)

It will eventually disappear as the bone remodels

Question 6

What is pictured here?

Answer 6

Alveolar Crest

The alveolar crests (arrows) are seen as cortical borders of the alveolar bone.

The alveolar crest is continuous with the lamina dura

In perio will become more radiolucent

Question 7

What is pictured here?

Answer 7

Trabecular Pattern

The trabecular pattern in the posterior mandible is quite variable, generally showing large marrow spaces and sparse trabeculation, especially inferiorly (arrow)

Question 8

What is pictured here?

Answer 8

Intermaxillary Suture

The intermaxillary suture (arrows) appears as a curved radiolucency in the midline of the maxilla

Question 9

What is pictured here?

Answer 9

Intermaxillary Suture

The intermaxillary suture may terminate in a V shaped widening (arrow) at the alveolar crest.

This is a normal variation and should not be confused with alveolar bone loss associated with periodontal disease

Question 10

What is pictured here?

Answer 10

Anterior Nasal Spine

The anterior nasal spine is seen as an opaque, irregular, or V-shaped projection from the floor of the nasal aperture in the midline (arrow)

Question 11

What is pictured here?

Answer 11

The anterior floor of the nasal aperture (arrows) appears as opaque lines extending laterally from the anterior nasal spine

Question 12

What is pictured here?

Answer 12

The nasal septum (black arrow) arises directly above the anterior nasal spine and is covered on each side by mucosa (white arrow)

Question 13

What is pictured here?

Answer 13

Nasal Floor

The floor of the nasal cavity, or hard palate (arrows) extends posteriorly, superimposed over the maxillary sinus

Question 14

What is pictured here?

Answer 14

The floor of the nasal aperture (arrows) often may be seen extending posteriorly from the anterior nasal spine above the maxillary lateral incisor & canine

Question 15

What is pictured here?

Answer 15

Incisive Canal

Often termed nasopalatine duct

It is a midline structure in the maxilla

Carries neurovascular structures

Superimposed over the intermaxillary suture (vertical line)

The whole shadow is the incisive canal

Can even be superimposed over the teeth

Question 16

What is pictured here?

Answer 16

Sagittal cone beam computed tomography sections through the midsagittal plane showing the course of the nasopalatine canal (yellow arrow) and the opening of the incisive foramen (white arrow)

Canals can vary in size

Question 17

What is pictured here?

Answer 17

The superior foramina of the nasopalatine canal (arrows) appear just lateral to the nasal septum and posterior to the anterior

Question 18

What is pictured here?

Answer 18

Lateral Fossa

(A) CBCT section through the long axis of a maxillary lateral incisor showing the lateral fossa as a depression on the buccal surface (arrow)

(B) the lateral fossa is a diffuse radiolucency (arrows) int eh region of the apex of the lateral incisor

Question 19

What is pictured here?

Answer 19

Soft tissue of the nose

The soft tissue outline of the nose (arrows) is superimposed on the anterior maxilla

Question 20

What is pictured here?

Answer 20

Nasolacrimal Canals

The nasolacrimal canals are commonly seen as ovoid radiolucencies (arrows) on maxillary occlusal projections

They should not be confused with the greater palatine foramina, which are not apparent on maxillary occlusal projections

Question 21

What is pictured here?

Answer 21

Maxillary Sinus

The inferior border of the maxillary sinus (arrows) appears as a thin radiopaque line near the apices of the maxillary premolars and molars

Here the 6 is not piercing through the maxillary sinus floor it’s just sitting behind it. Sinus floor can be superimposed over the apical 3rdof roots, doesn’t mean its extending into the apical 3rd

Question 22

What is pictured here?

Answer 22

The anterior border of the left maxillary sinus (white arrows) crosses the floor of the nasal fossa (black arrow)

Question 23

What is pictured here?

Answer 23

Sinus Septum

Normal variant

Not pathological

Question 24

What is pictured here?

Answer 24

Zygomatic Process

The zygomatic process of the maxilla (arrows) protrudes laterally from the maxillary wall

Its size may be quite variable: small with thick borders (A) or large with thin borders (B)

Question 25

What is pictured here?

Answer 25

**Nasolabial Fold** The nasolabial soft tissue fold (arrows) extends across the canine-premolar region

Question 26

What is pictured here?

Answer 26

**Pterygoid Plates** Pterygoid plates (arrows) located posterior to the maxillary tuberosity

Question 27

What is pictured here?

Answer 27

**Genial Tubercules** The genial tubercles (arrow) appear as a radiopaque mass, in this case without evidence of the lingual foramen

Question 28

What is pictured here?

Answer 28

**Lingual Foramen & Canal** (A) lingual foramen on a periapical view (arrow) with a sclerotic border, in the symphyseal region of the mandible (B) cone beam sagittal section through mandibular midline shows superior lingual foramen extending deep into the mandible from the lingual surface

Question 29

What is pictured here?

Answer 29

**Mental Fossa** The mental fossa is a depression on the anterior surface of the mandible and is seen as a radiolucent area with ill-defined borders (arrows) in the region of the incisor roots

Question 30

What is pictured here?

Answer 30

**Mental Foramen** The mental foramen (arrow) appears as an oval radiolucency typically near the apex of the second premolar

Question 31

What is pictured here?

Answer 31

**Mental Foramen** The mental foramen (arrow) (over the apex of the 2ndpremolar) may stimulate periapical disease However, continuity of the lamina dura around the apex indicates the absence of periapical abnormality

Question 32

What is pictured here?

Answer 32

**Mandibular Canal** (A) on periapical view, arrows denote radiopaque superior and inferior cortical borders (B) cone beam section through the body of the mandible shows corticated borders of the inferior alveolar canal (C) Cone beam cross-sectional view shows the circular inferior alveolar canal with corticated borders lying adjacent to the lingual plate

Question 33

What is pictured here?

Answer 33

Superimposition of the inferior alveolar canal over the apex of a molar causes the image of the periodontal ligament space to appear wider (arrow) However, the presence of an intact lamina dura indicates that there is no periapical disease

Question 34

What is pictured here?

Answer 34

**Nutrient canals** Nutrient canals (arrows), demonstrated by radiopaque cortical borders, descend from the mandibular first molar Nutrient canals at this location are a common finding

Question 35

What is pictured here?

Answer 35

**Nutrient Canals** Nutrient canals seen as vertical radiolucent structures (arrows) in the anterior mandible are often associated with periodontal disease as in this patient Not fractures !! just normal nutrient canals – if you were to extract these teeth there would be more bleeding

Question 36

What is pictured here?

Answer 36

**Mylohyoid Ridge** Mylohyoid ridge (arrows) running at the level fo the molar apices and above the inferrio alveolar canal

Question 37

What is pictured here?

Answer 37

**Submandibular Fossa / Concavity** Submandibular gland fossa (arrows) indicated by a radiolucent region with ill-defined borders & sparse trabecular bone lying inferiorly to the mandibular molars

Question 38

What is pictured here?

Answer 38

**Oblique Ridge** External oblique ridge (arrows) on the buccal surface of the mandible, seen as a radiopaque line near the alveolar crest in the mandibular third molar region

Question 39

What is pictured here?

Answer 39

**Inferior cortical border of the mandible** The inferior border of the mandible (arrows) is seen as a dense, broad radiopaque band

Question 40

Label this diagram

Answer 40

1. anterior nasal spine 2. interseptal bone 3. crestal alveolar bone 4. inferior turbinate (concha) 5. cartilaginous nasal septum 6. inferior process of ethmoid bone 7. nasal fossa 8. infraorbital foramen 9. zygomatic process of maxilla 10. mental ridge 11. mental foramen 12. external oblique ridge 13. retromolar trigone 14. zygomatico-maxillary suture 15. zygomatic bone 16. zygomatico-temporal suture 17. zygomatic process of temporal bone 18. nasal bone 19. zygomatico-frontal suture

Question 41

Label this diagram

Answer 41

1. common carotid artery 2. external carotid artery 3. internal carotid artery 4. facial artery 5. inferior alveolar artery 6. internal maxillary artery 7. posterior superior alveolar arteries 8. infraorbital artery 9. labial artery 10. incisive artery

Question 42

Label this diagram

Answer 42

1. hard palate 2. infundibulum 3. ostium of nasolacrimal canal 4. inferior turbinate 5. middle turbinate 6. nasal bone 7. nasolacrimal canal 8. frontal sinus 9. sphenoid sinus 10. pituitary fossa 11. medial pterygoid plate 12. lateral pterygoid plate 13. hamular process of medial pterygoid plate (hamulus) 14. maxillary tuberosity 15. incisive foramen 16. median maxillary suture (midpalatal suture) 17. palatal process of maxilla 18. palato-maxillary suture (transverse) 19. shadow of nasolacrimal duct 20. palatine bone 21. greater palatine foramen 22. lesser palatine foramen 23. posterior nares 24. foramen of Stenson 25. incisive canal 26. foramen of Scarpa

Question 43

Label this diagram

Answer 43

1. lateral fossa 2. maxilla 3. vertical process of maxilla 4. floor of nasal fossa 5. vomer bone 6. palato-maxillary suture 7. palatal bone 8. posterior nasal spine 9. sinus recess / alveolar recess of sinus 10. maxillary sinus 11. bony septum of maxillary sinus 12. anterior nasal spine

Question 44

Label this diagram

Answer 44

1. mental ridge 2. mandibular symphysis 3. mental foramen 4. mandibular body 5. external oblique ridge 6. angle of mandible 7. retromolar trigone 8. ramus 9. neck of condyle 10. head of condyle 11. sigmoid notch 12. coronoid process 13. medial sigmoid depression 14. mandibular foramen 15. lingula

Question 45

Label this diagram

Answer 45

1. coronoid process 2. sigmoid notch 3. head of condyle 4. medial sigmoid depression 5. mandibular foramen 6. angle of mandible 7. inferior cortex of mandible 8. digastric fossa 9. submandibular (salivary gland) fossa 10. mylohyoid (internal oblique) ridge 11. inferior genial tubercle of geniohyoid muscle 12. superior genial tubercle of genioglossus muscle 13. accessory lingual foramen for lingual vessels (lingual foramen)

Question 46

Label this diagram

Answer 46

1. Mylohyoid ridge / internal oblique ridge 2. Submandibular fossa (left) 3. Left mandibular canal OR Left inferior dental/alveolar canal 4. Left mental foramen 5. Incisive branches & anterior loop of the mandibular canal

Question 47

Label this diagram

Answer 47

1. inferior cortex of mandible 2. inferior alveolar canal 3. lamina dura (radiopaque thin white line) 4. periodontal membrane space (radiolucent thin black line) 5. coronal pulp space (pulp chamber) 6. interproximal contact point 7. dentin 8. enamel 9. interseptal alveolar bone (interradicular alveolar bone) 10. crestal plate (thin white radiopaque line) 11. root canal space (containing the dental pulp) 12. cementum (frequently not distinguishable from the subadjacent dentine unless hypercementosis is present)

Question 48

Label this diagram

Answer 48

1. soft tissue shadow of upper lip 2. cervical margin (line) of enamel 3. alveolar bone margin (dark band between 2 and 3 is the root) 4. median maxillary suture 5. soft tissue outline of nose 6. incisive foramen

Question 49

Label this diagram

Answer 49

1. orifice of nasolacrimal duct (at infundibulum of the inferior turbinate not seen) 2. lateral wall of nasal fossa 3. #23 4. #24 5. #25 6. #21 7. #22 8. #63 9. #64 10. #65

Question 50

Label this diagram

Answer 50

1. embossed dot on film 2. soft tissue outline of nasolabial fold 3. floor of maxillary sinus 4. bony septum in maxillary sinus 5. air space of maxillary sinus 6. metal part in bite-block

Question 51

Label this diagram

Answer 51

1. zygomatic process of maxilla 2. hard palate/floor of nose 3. nasal mucosa 4. nasal cavity 5. maxillary sinus air space 6. sinus septum 7. floor of maxillary sinus 8. mucosa of alveolar ridge 9. alveolar bone of maxilla

Question 52

Label this diagram

Answer 52

1. sinus floor mucosa 2. floor of maxillary sinus 3. zygomatic process of maxilla 4. air space of maxillary sinus 5. bony septum in maxillary sinus 6. sinus mucosa on both sides of septum 7. mucosal lining 8. soft tissue superimposition

Question 53

Label this diagram

Answer 53

1. maxillary sinus air space 2. zygomatic arch 3. medial pterygoid plate 4. lateral pterygoid plate 5. hamular process of medial pterygoid plate 6. maxillary tuberosity 7. floor of maxillary sinus 8. coronoid process of mandible 9. embossed dot in film 10. “ks” marking indicating “D” speed film 11. bite-block

Question 54

Label this diagram

Answer 54

1. mental foramen (does not usually have a corticated margin) 2. inferior cortex of mandible

Question 55

Label this diagram

Answer 55

1. inferior cortex 2. inferior cortical border 3. genial tubercles 4. lingual foramen 5. lingual canal 6. mental ridge 7. soft tissue shadow of lower lip

Question 56

Label this diagram

Answer 56

1. genial tubercles 2. lingual foramen 3. inferior cortex 4. #31 5. #32 6. #73 7. #74 8. #33 9. #34 10. #35