8. Anatomy of maxillofacial skeleton and intro to radiological interpretation

Question 1

LOs

Answer 1

• Describe the maxilla in detail (including the main foramina and the maxillary antra)
• Describe the mandible in detail, including its shape, internal structure and main foramina

Question 2

why is it important to be aware of the bony anatomy of the whole skull?

Answer 2

• radiographic images = 2d
• Soft tissue shadowing = mostly irrelevant
• hence important that aware of bony anatomy of whole skull
• particularly maxilla and mandible

Question 3

maxilla structure front view?

Answer 3

• UPPER JAW ‘
• hole of Nasal cavity
  1. nasal septum (between nasal septum)
  2. inferior nasal conchae
  3. floor of the nose (above apices of upper anteriors)

4. Surface anatomy around teeth themself:
   - undulation to accommodate for roots
   - where root = bump / prominence
   - between roots = dip / concavity

Question 4

maxilla structure - side view?

Answer 4

1. • Bony spike of anterior nasal spine at front of nasal cavity
2. Posteriorly, maxilla widens and articulates with the zygomatic bone (cheekbone)(bone)
3. displays what lies under surface layer of the maxilla
   = maxillary air sinus / antrum:

Extends posteriorly to hollow the zygoma, and anteriorly extends to the midline = variation in density & size
Thin sinus walls and floor can appear as dense opaque lines when viewed from the front, even though they are thin - can appear as overlapping lobes
Ridges and bumps: surface not smooth
Delimited by the maxillary alveolar bone
–> periapicals of bicuspid-molar area

Question 5

features of antrum (maxillary air sinus)

Answer 5

3.
- can be quite large
- Extends posteriorly to hollow the zygoma
- anteriorly extends almost to midline = variation in density & size

• radiographically evident on most upper posterior teeth

4.
- internally sinus surface not smooth = small and bumps

• cross section = thin sinus walls and floor
• front view = can appear as dense white opaque line radiographically

Question 6

maxilla structure - lateral view?

4. structure below thin bone covering teeth

Answer 6

1.
zygomatic bone

2.
- undulating surface of the maxilla
- bony bump over canine = canine prominence.

3.
- tuberosity
- Posteriorly behind wisdom tooth = smooth rounded end of maxilla

4. • roots of teeth = visible + positioned within alveolar part of maxilla
   • alveolar bone = internal honey-comb trabecular pattern = wide enough to envelope all roots of posterior teeth

Question 7

affects of zygomatic bone on radiograph?

Answer 7

• shows bulk + prominence of zygomatic cheekbone
• can radiographically overline apical tissues of upper molar teeth = cast solid dense white shadow
• if hollowed out by extension of the maxillary air sinus, radiographically it casts a white radiopaque U shape shadow with a radiolucent black centre

Question 8

palate structure

Answer 8

1. • lid palatal suture

2.
- nasopalatine foramen
- Found palatally positioned between upper central incisors
- Radiolucent appearance

Question 9

is it buccally or behind teeth in palate?

Answer 9

• radiographically cannot tell
• but features, shape + position indicate it’s palatally positioned nasopalatine foramen

Question 10

Answer 10

2- nasal septum forms dense thin white line
3- hollow nasal cavity = more radiolucent zone
4 - nasal conchae = less dense, opaque shadow

Question 11

Answer 11

1. • slight increase in opacity
   • distinct lower margin
   • caused by tip of tissues on nose
2. • thin black line

Question 12

Answer 12

• occlusal view
• shows how maxillary air sinus varies in size

1.
- patient RHS maxillary air sinus
- relatively large
- creates large area of radiolucency within palate

2. patient LHS, maxillary air sinus creates radiolucent / black shadow
3. • RHS density of sinus shadow varies
   • as shape of sinus varies
   • density of overlying bone varies

Question 13

Answer 13

• periapical radiograph

Question 14

Answer 14

1. radiolucent antal air cavity
2. surrounding radiopaque anterior line and wall

Question 15

Answer 15

• posterior part of maxilla

Question 16

Answer 16

• periapical

1. lower edge of dense zygomatic bone
2. posterior aspect of the maxilla = smooth rounded tuberosity
   - behind upper posterior teeth

Question 17

Answer 17

1 = geometrically distorted but 2 not

Question 18

Answer 18

1. pterygoid hamulus
   - supports muscles of soft tissues
2. coronoid process

Question 19

Answer 19

1. zygomatic bone
   - u shaped radiopaque edge
   - holled out by maxillary air sinus
2. floor of maxillary sinus
3. lower edge of maxillary alveolars
4. coronoid process
5. zygomatic bone

Question 20

Answer 20

1. mental prominence (chin)
2. body
3. mental foramina
4. bony prominence of external oblique ridge

5.
angle

6. angle
7. coronoid process
8. ascending rami

Question 21

Answer 21

• lingual aspect anteriorly

4. genial tubercles
   - bony spurs
   - where some of muscles of tongue and neck attach to mandible
5. lingual pit
6. mylohyoid ridge
   - ridgid bone to which mylohyoid muscle attaches to form floor of mouth

1+2.
- thicken bone of mylohyoid ridge
- indentation of submandibular fossa

Question 22

Answer 22

outer buccal surface of bone has been removed
and some internal bone to display roots

1.
- roots of teeth extend into underlying trabecular bone

2. • inferior dental nerve
3. mental nerve
   - coming out of dental foramen

Question 23

Answer 23

sectioned longitudinally

1. • displays honey cone pattern of trabecular bone
2. • dense outline of individual sockets of teeth
3. • very dense cortical bone that forms the lower border

these features can be identified radiographically

Question 24

Answer 24

1. honey comb pattern of internal trabecular bone
2. mental foramen
   - little, round black, radiolucency in region of 1st + 2nd premolars

Question 25

Answer 25

Question 26

Answer 26

Question 27

Answer 27

finish 25 minutes

Question 28

Answer 28

finish 26 minutes

Question 29

Answer 29

finish 26:30

Question 30

Answer 30

Question 31

EXTRA SUMMARY AZ NOTES - radiograph features

Question 32

Maxillary air sinus/antrum

Answer 32

Lies underneath surface of maxilla
- Extends anteriorly almost to midline
- Posteriorly can hollow out the body of zygoma
- Walls and floor of sinus can appear as dense white opaque white line
- Density of sinus shadow caries due to variation of sinus shape and density
of overlying bone

Question 33

Zygomatic Bone

Answer 33

Lateral view of skull shows bulk and prominence of zygoma
- Radiographically can overlie the apical tissues of upper molar teeth
casting solid dense white shadow – radiopacity
- Can be hollowed out by extension of sinus hence radiographically casts
white radiopaque U shape shadow with black radiolucent centre

Question 34

Nasopalatine Foramen

Answer 34

• Found palatally positioned between upper central incisors
• Radiolucent appearance

Question 35

Nose

Answer 35

When X-ray passes through tip of nose can sometimes cast shadow
superimposed over top of image of teeth
- Usually affects apices of 2 central incisors where there is slight increase in
opacity

Question 36

Mid-palatal suture

Answer 36

• Fibrous junction of 2 halves of palate
• Radiographically can be depicted as thin black line

Question 37

Pterygoid Hamulus

Answer 37

• Spur of bone supporting muscles of soft palate
• Radiopaque structure found posteriorly

Question 38

Coronoid Process

Answer 38

• Structure from mandible
• Radiopaque structure

Question 39

Mental Foramen

Answer 39

• Circular black radiolucent appearance
• Located in region of first/second premolars

Question 40

Lamina Dura

Answer 40

• Effectively the cortical bone surrounding the tooth socket
• Evident as white radiopaque line around tooth root

Question 41

Lingual Pit

Answer 41

Appears as radiolucent area
- Found in radiographs of lower anterior teeth

Question 42

Genial Tubercles

Answer 42

Radiolucent band
- Located within posterior part of body of mandible
- Edges of canal may appear as thin white opaque lines sometimes referred
to as tramlines