8. Anatomy of maxillofacial skeleton and intro to radiological interpretation Flashcards
LOs
- 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
why is it important to be aware of the bony anatomy of the whole skull?
- radiographic images = 2d
- Soft tissue shadowing = mostly irrelevant
- hence important that aware of bony anatomy of whole skull
- particularly maxilla and mandible
maxilla structure front view?
- 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)
- Surface anatomy around teeth themself:
- undulation to accommodate for roots
- where root = bump / prominence
- between roots = dip / concavity
maxilla structure - side view?
- Bony spike of anterior nasal spine at front of nasal cavity
- Posteriorly, maxilla widens and articulates with the zygomatic bone (cheekbone)(bone)
- 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
features of antrum (maxillary air sinus)
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
maxilla structure - lateral view?
- structure below thin bone covering teeth
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
- 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
affects of zygomatic bone on radiograph?
- 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
palate structure
- lid palatal suture
2.
- nasopalatine foramen
- Found palatally positioned between upper central incisors
- Radiolucent appearance
is it buccally or behind teeth in palate?
- radiographically cannot tell
- but features, shape + position indicate it’s palatally positioned nasopalatine foramen
2- nasal septum forms dense thin white line
3- hollow nasal cavity = more radiolucent zone
4 - nasal conchae = less dense, opaque shadow
- slight increase in opacity
- distinct lower margin
- caused by tip of tissues on nose
- thin black line
- 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
- patient LHS, maxillary air sinus creates radiolucent / black shadow
- RHS density of sinus shadow varies
- as shape of sinus varies
- density of overlying bone varies
- periapical radiograph
- radiolucent antal air cavity
- surrounding radiopaque anterior line and wall
- posterior part of maxilla
- periapical
- lower edge of dense zygomatic bone
- posterior aspect of the maxilla = smooth rounded tuberosity
- behind upper posterior teeth
1 = geometrically distorted but 2 not
- pterygoid hamulus
- supports muscles of soft tissues - coronoid process
- zygomatic bone
- u shaped radiopaque edge
- holled out by maxillary air sinus - floor of maxillary sinus
- lower edge of maxillary alveolars
- coronoid process
- zygomatic bone
- mental prominence (chin)
- body
- mental foramina
- bony prominence of external oblique ridge
5.
angle
- angle
- coronoid process
- ascending rami
- lingual aspect anteriorly
- genial tubercles
- bony spurs
- where some of muscles of tongue and neck attach to mandible - lingual pit
- 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
outer buccal surface of bone has been removed
and some internal bone to display roots
1.
- roots of teeth extend into underlying trabecular bone
- inferior dental nerve
- mental nerve
- coming out of dental foramen
sectioned longitudinally
- displays honey cone pattern of trabecular bone
- dense outline of individual sockets of teeth
- very dense cortical bone that forms the lower border
these features can be identified radiographically
- honey comb pattern of internal trabecular bone
- mental foramen
- little, round black, radiolucency in region of 1st + 2nd premolars
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EXTRA SUMMARY AZ NOTES - radiograph features
Maxillary air sinus/antrum
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
Zygomatic Bone
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
Nasopalatine Foramen
- Found palatally positioned between upper central incisors
- Radiolucent appearance
Nose
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
Mid-palatal suture
- Fibrous junction of 2 halves of palate
- Radiographically can be depicted as thin black line
Pterygoid Hamulus
- Spur of bone supporting muscles of soft palate
- Radiopaque structure found posteriorly
Coronoid Process
- Structure from mandible
- Radiopaque structure
Mental Foramen
- Circular black radiolucent appearance
- Located in region of first/second premolars
Lamina Dura
- Effectively the cortical bone surrounding the tooth socket
- Evident as white radiopaque line around tooth root
Lingual Pit
Appears as radiolucent area
- Found in radiographs of lower anterior teeth
Genial Tubercles
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
