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Imaging Of Facial Trauma Part 2
1. Imaging of Facial Trauma
Part 2: Introduction and Anatomy
Rathachai Kaewlai, MD
www.RadiologyInThai.com
Created: January 2007
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2. Outline
Facial fracture epidemiology Types of facial fracture
Nasal bone fracture
Initial management Naso-orbital-ethmoid fracture
Frontal sinus fracture
Imaging: CT versus radiography Orbital fracture
Zygomatic fracture
Normal anatomy
Maxillary fracture
3D Mandibular fracture
CT (axial, coronal and sagittal planes)
Radiography Imaging approach
Biomechanics
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3. Plain Film Radiography
Can be obtained to screen for facial injury if CT is not immediately
available
If plain film identify a fracture other than a simple nasal bone
fracture, further evaluation by CT is indicated
Multiple plain film projections are relative to ‘canthomeatal line’; an
imaginary line drawn from outer canthus to external auditory meatus
Proper positioning (of patient’s head), alignment of x-ray beam is
critical for evaluation because facial skeletal anatomy is complex
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4. Plain Film Radiography
Remember: plain film is a 2D image of a 3D object
Overlapping structures significantly obscure anatomic detail
This problem is solved by standard views (to minimize overlap,
allow visualization of important structures, familiarity for
interpretation)
Rule of symmetry: two sides of the face are quite symmetrical
Symmetry is usual, and asymmetry is suspect
Multiplicity: fractures of facial bones are frequently multiple.
Do not stop looking for others when see one
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5. Plain Film Radiography
Facial series Mandible
Water’s view (PA view with Oblique view, Towne’s view
cephalad angulation)
Caldwell view (PA view) Orthopanthogram
Towne’s view
Lateral view
Base view
Additional view
Lateral view of the nasal bone
(nasal technique)
Note: The lecture series are focused on CT scan
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6. Water’s View
The most comprehensive single
projection display
Excellent view of
- Maxilla
- Maxillary sinuses
- Zygoma
- Zygomatic arches
- Rims of orbits, esp. floor
- Nasal bones
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7. Water’s View
Key structures
1 = Frontal sinus
2 = Maxillary sinus
3 = Frontal process of
Zygoma
4 = Body of Zygoma (malar
eminence)
5 = Temporal process of
Zygoma
Dotted line = zygomatico-
frontal suture
Dolan’s lines of reference
Line A, B, C
Rule:
smooth, non-disrupted, same
contour on both sides
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8. Line A
- Begins at inner surface of
zygomatico-frontal suture,
follows orbital surface of
zygoma, maxilla, frontal
process of maxilla and arch
of nasal bone
- If drawn to both sides, the
line is similar to lazy ‘W’ or
half frame of reading glasses
Line B
- egins at lateral and inferior
B
margin of maxilla and
extends along lateral wall of
maxillary sinus and inferior
surface of zygomatic arch
- Ends at glenoid fossa
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9. Line C
- Begins at lateral and inferior
margins of maxilla, extends
along lateral wall of
maxillary sinus and inferior
surface of zygomatic arch
- Ends at glenoid fossa
“Friendly Line”
- Medial half of Line C is the
anterolateral wall of the
maxillary sinus.
- If it is disrupted, the
possibilities of fx include
1) Isolated maxillary
antrum
2) Zygomatico-maxillary
complex (ZMC)
3) LeFort (unilateral or
bilateral)
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10. Caldwell’s View
Excellent view of
- Entire rim of orbit, esp.
superomedial rim
- Ethmoid sinus
- Floor of orbit may be well
seen in petrous bones are
projected below the inferior
orbital rim (not in this
example)
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11. Key structures
1 = Ethmoid sinuses
2 = Orbit
Line A, B, C, D = superior,
2 lateral, inferior and medial
walls of the orbit, respectively
Line E = midline nasal
septum and vomer
Rule:
- Ethmoid sinuses density
should be equal, darker than
orbit
- Smooth non-disrupted
orbital walls
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12. Lateral View
Excellent view of
- Frontal sinus: anterior wall
- Maxillary sinus: anterior
and posterior wall
- Sphenoid sinus
- Pterygoid plate
- Floor of anterior cranial
fossa, hard palate
- Lateral rim of orbit
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13. Key structures
1 = Frontal sinus
2 = Maxillary sinus
3 = Sphenoid sinus
4 = Hard palate
5 = Anterior wall of temporal
fossa
Between green arrows =
Pterygoid plate
Line A = Anterior wall of
frontal sinus
Line B = Anterior cranial
fossa
Line C = Anterior wall of
maxillary sinus
Line D = Posterior wall of
maxillary sinus
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14. Line A
- Connects anterior surface of
frontal sinus and anterior
surface of hard palate
Line B
- Connects anterior wall of
temporal fossa and posterior
edge of hard palate
Line C
- Along planum sphenoidale
Line D
- Along hard palate
Rule:
- Line A & B parallel
- Line C & D parallel
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16. Key structures
1 = Zygomatic arch
Line A = Posterolateral wall
of maxillary sinus
Rule:
- Smooth, non-disrupted line
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17. Orthopanthogram or Panorex®
Key structures
R = Temporomandibular joint
13 = Mandible, condyle 14 = Mandible, ramus 17 = Mandible, body
18 = Mandible, angle 19 = Mandible, coronoid process 20 = Mandible, symphysis
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18. 8 9
25 24
Counting the teeth on Orthopanthogram or Panorex®
American Dental Association (ADA) system preferred this system because you will speak same ‘language’ with
dentists.
Count from midline and go laterally (some individuals may not have #1, #16, #17, and #32)
Maxillary Arch ADA#1 - 8 (right), #9-16 (left)
Mandibular Arch ADA#32-25 (right), #24-17 (left)
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19. Oblique View of Mandible
Key structures
R = Temporomandibular joint
13 = Mandible, condyle 14 = Mandible, ramus 17 = Mandible, body
18 = Mandible, angle 19 = Mandible, coronoid process 20 = Mandible, symphysis
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20. Biomechanics
LeFort described areas of
relative strength within the
facial skeleton
Alveolar process of maxilla
(1)
Frontal process of maxilla
(2)
Body of zygoma or malar
eminence (3)
Line of fracture tends to
avoid these areas
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21. Checklist for Facial
Radiograph/CT
Facial structures are quite symmetrical
Do not stop searching when see one abnormality
If suspect for more than simple nasal fracture, do CT
Significant (but can be subtle) fractures
Fracture involves the optic foramen which can cause permanent visual loss if
not treated promptly
Fracture of the posterior wall of frontal sinus requires neurosurgical
evaluation and may require antibiotics prophylaxis
Fracture/dislocation of the TMJ usually missed on initial survey. It can cause
significant disability if left untreated
Look for significant soft tissue injuries
Globe rupture, hemorrhage
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23. The information provided in this presentation…
Is intended to be used as educational purposes only.
Is designed to assist emergency practitioners in providing
appropriate radiologic care for patients.
Is flexible and not intended, nor should they be used to
establish a legal standard of care.
Thanks, MGH Radiology, for cases I’ve seen and things I’ve
learned.
R.K.
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