Concluding the last portion of imaging of facial trauma.

1. Imaging of Facial Trauma
Part 3: Pathology
(Zygomatic, Maxillary and Mandibular Fractures)
Rathachai Kaewlai, MD
www.RadiologyInThai.com
Created: January 2007
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2. Outline
 Facial and mandibular fractures
 Nasal fractures
 Naso-orbital-ethmoidal fractures
 Frontal sinus fractures
 Orbital fractures
 Zygomatic fractures
 Maxillary fractures
 Mandibular fractures
 Imaging approach
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3. Zygomatic Fractures
 Two types of zygomatic fractures
 Zygomatic complex fracture
 Isolated zygomatic arch fracture
 Relevant anatomy
 Malar eminence = surface anatomy of the
body of zygoma
 Zygomatic fractures can cause limitation of
mandibular motion, especially when
fractures are depressed
 Masseter muscle arises from zygomatic arch
 Coronoid process is located underneath the
zygomatic arch
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4. Zygomatic Fractures
 Zygomatic complex fractures
 AKA ZMC fracture, trimalar fracture, malar eminence fracture
 Tripod fracture is a misnomer (zygoma actually has 2 attachments
to cranium and 2 to maxilla)
 Principal lines involve 3 components
 Orbital process of zygoma
 Inferior rim of orbit
 Zygomatic arch
 Main fragment is zygoma, which is separated from its three
areas of attachment
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5. Zygomatic Fractures
 Zygomatic complex fractures
 Fractures almost invariably traverse the infraorbital nerve foramen
(located in the orbital floor), causing impaired sensation of the
cheek and a portion of the upper lip. However in majority of
cases, the nerve is usually intact
 Image interpretation should pay additional attention to
 Alignment of zygoma (depressed, rotated)
 Lateral orbital wall alignment (posterior relationship of zygoma and
sphenoid bones)
 Angulation of the wall results in increased orbital volume and
enophthalmos
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6. Zygomatic Fractures
 Isolated zygomatic arch fracture
 Etiology: direct blow by small object
 Commonly consists of 3 fracture lines:
 One at each end and the third in the center with depression of
fracture fragment
 Limited motion of mandible may occur if the fracture
impinges on coronoid process or simply because the masseter
muscle arises from zygomatic arch
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7. Zygomatic Complex Fractures
60-year-old man fell onto the left cheek.
Axial and coronal reformatted CT images show typical left ZMC fractures: anterior/
posterior walls of maxillary sinus including rim (red arrows), zygomatic arch (green arrow), and
orbital process of zygoma (blue arrow). Left orbital floor ‘blow-out’ fracture with intraorbital
fat herniation is seen in coronal image. Orbital floor fracture is commonly associated with
ZMC fractures.
H = Hemosinus, = Soft tissue emphysema due to communication with fractured sinus
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8. Zygomatic
Complex Fractures
Same patient as in the
previous page
3D image shows all
components of left
ZMC fractures
including the inferior
orbital rim (red arrows),
zygomatico-frontal
separation (blue arrow),
zygomatic arch (green
arrow).
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9. Isolated Zygomatic Arch Fractures
23-year-old man was punched by a left-handed.
Classic zygomatic arch fractures occur in three sites along the arch. The middle
fracture causes fracture fragment depression.
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10. Maxillary Fractures
 Types of maxillary fractures
 Maxillary sagittal fracture (maxillary sinus fracture)
 Palate fracture
 Alveolar process fracture
 LeFort fractures
 LeFort I fracture
 LeFort II fracture
 LeFort III fracture
 Combination (bilateral, hemi-)
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11. Maxillary Fractures
 Maxillary sagittal fracture
 AKA maxillary sinus fracture
 Fracture of a maxilla in sagittal plane, involving anterior-lateral
wall of a maxillary sinus (LeFort fractures represent bilateral
maxillary fractures)
 Due to direct blow to either right or left midface
 Plain film shows opacified maxillary sinus, however it is
usually inadequate for diagnosis
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12. Maxillary Sagittal Fracture
68-year-old man was found
down.
There is a sagittal plane
fracture of the left maxillary
sinus (red arrow) with
hemosinus (H)
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13. Maxillary Fractures
 Isolated alveolar process fracture
 Fracture of any portion of the alveolar process
 Clinically evident by malalignment and displacement of teeth
contained within fractured segment
 Even on CT, fracture may be subtle and easily overlooked
 Further imaging may be needed when the diagnosis is made
 X-ray of the teeth or a panoramic view (look for dental injuries)
 Chest radiograph (look for aspirated teeth)
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14. Maxillary Alveolar Process Fractures
Middle age women fell onto her mouth.
Red arrows show the comminuted fractures of the maxillary alveolar process on
the right side. These fractures are considered ‘open’ as they are connected to the
oral cavity.
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15. LeFort Fractures
 Among the most severe fractures seen in face and associated with
high-energy trauma
 Named after René LeFort, a French physician, who studied facial
fractures in cadavers. Result was published in 1901
 Key facts
 In each type, there is a partial or complete separation of maxilla from
the remainder of the facial skeleton
 All LeFort fractures must extend through posterior face, transects the
pterygoid processes
 Any combination of LeFort I, II, and III patterns can occur
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16. LeFort Fractures
 LeFort I fracture
 Definition: transmaxillary fracture
 Transverse (horizontal) fracture of inferior maxillae, involving maxillary
sinuses (all except superior walls), lateral margin of nasal fossa, nasal
septum and pterygoid plates
 Clinical: free floating and movable hard palate with maxillary teeth
 Imaging findings
Opacified bilateral maxillary sinuses

Transverse fracture through the inferior maxillae above hard palate

Best shown and confirmed by coronal and sagittal reformatted CT images

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17. LeFort I Fracture
48-year-old man was kicked by a horse.
LeFort I fracture line along bilateral maxillary sinuses (red arrows). Pterygoid plate
fractures are not shown
H = Hemosinus, Blue arrow = Mandibular fracture
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18. LeFort Fractures
 LeFort II fracture
 Pyramid-shaped maxillary fracture, involving maxillary sinuses
(anterior-lateral walls), inferior orbital rim, orbital floor and
nasofrontal suture
 Clinical: free floating, movable midface including maxillary
teeth, hard palate and nose
 Imaging findings:
 Opacified bilateral maxillary sinuses and orbital emphysema
 Fractures of anterior/lateral walls of maxillary sinuses, inferior
orbital rims/floors and disruption of nasofrontal suture
 Best seen and confirmed by coronal reformatted CT images
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19. LeFort II Fracture
Middle age man in motor vehicle accident.
Fracture lines are demonstrated in red arrows.
Fracture of pterygoid plates are present in all
type of LeFort fractures.
H = Hemosinus
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20. LeFort Fractures
 LeFort III fracture
 AKA craniofacial disjunction
 This fracture separates calvaria (skull) from the facial bones. Most severe
of all LeFort fractures
 Definition: separation of facial bones from the skull
Zygomas separated from sphenoid at zygomatico-sphenoid sutures

 Nasal bones and medial orbital walls separated from frontal bone at nasofrontal
sutures
 Best seen in coronal images
 Clinical: movement of face relative to the skull
 Imaging findings:
 Plain film will underestimate degree of injury due to severe soft tissue swelling
obscuring the bony details. CT is recommended
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21. Combined LeFort II and
III Fractures
32-year-old man, unrestrained
driver in a motor vehicle
accident.
Blue arrows define LeFort II
fracture.
Red arrows define the
LeFort III fracture.
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22. Mandibular Fractures
 Motor vehicle collisions and assaults together account for more than
80% of mandible fractures
 Incidence
 Ratio of mandibular to facial fractures = 2:1
 Co-existence of mandibular and facial fractures = 6-10%
 Rare in children
If occurs, condyle is the most common location

Condyle is the growth center of mandible. Trauma to this area can retard

growth and cause facial asymmetry
 Clinical
 Laceration under chin (common)
 Pain, malocclusion, deviation of mandible on opening mouth
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23. Mandibular Fractures
 Mandible is divided into region for purpose of describing location
of fractures
 Symphysis (= within the boundaries of central incisors)
 Parasymphysis (within the boundaries of vertical lines distal to canine
teeth)
Body (include the region of third molar)

Angle (distal to the third molar)

Ramus

Condylar process (has separate classification system)

Coronoid process

Alveolar process (region normally contains teeth)

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24. Mandibular Fractures
 Relevant anatomy
 Mandible is a ring or arc bone which is usually difficult to break in
one location. Approximately half of mandible fractures occur in
multiple locations.
 Search for a second fracture after initial fracture is identified!
(usually at contralateral side)
 In angle fracture: 3 muscles attaching to the ramus of mandible
(masseter, temporalis and medial pterygoid) pull the proximal
fragment upward and medially
 In symphyseal, parasymphyseal fractures: Digastric, geniohyoid
and genioglossus muscles pull the symphysis downward
posteriorly
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25. Mandibular Fractures
 Imaging recommendation
 Plain film mandible series (PA, lateral, Towne’s and bilateral obliques)
show nearly all fractures BUT may be difficult to obtain in multi-trauma
patients
 Panoramic radiography (orthopantography)
Need patient in upright position

 Better to look for subtle tooth fracture
 CT
 Show all mandibular fractures AND other facial fractures (co-existence
6-10%), as well as position and alignment of fragments
 Display associated soft tissue injuries
 Easy to perform in multi-trauma patient
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26. Bilateral Mandibular Fractures/Dislocations
Red arrows = Mandibular condyles which are located
‘too anterior’ than usual
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27. Bilateral Mandibular Fractures/Dislocations
Same patient as in previous page. If plain film is to be used,
CT shows left symphyseal/ parasymphyseal fracture extending to the tooth make sure to have all
(green arrows), and bilateral mandibular condyle fractures (red arrows). The projections, adequate
findings represent ‘Flail mandible’.
coverage and optimal
Limitation of plain films in previous page is likely due to 1. Inadequate
technique. If in doubt, CT is
coverage (PA projection does not include the inferior part of mandible) 2.
the solution
Suboptimal technique (Oblique views are not true oblique)
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28. Mandibular Fractures
43-year-old man, fell from height, presented with Search for second site of
malocclusion fracture is warranted
Orthopantogram demonstrates a fracture of the right when one sees
ramus of mandible (red arrows). Subtle ‘second’ site of
mandibular fracture
fracture is at the left body (green arrows) which is confirmed
in CT scan (next page).
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29. Right Sagittal
Mandibular Fractures
Same patient as in previous page.
CT confirms the fractures of the right angle of mandible (red arrows) and left body (green
arrows). Axial image shows extension of fracture into the root of the left mandibular
tooth, indicating an open fracture
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30. Mandibular Fractures
21-year-old man was punched at his left face by the right-handed person.
Orthopantogram shows a nondisplaced fracture of the left angle of mandible (red arrows),
extending to the root of unerupted ADA #18.
Where is the second site of fracture?
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31. Mandibular Fractures
Same patient as previous page.
CT Orthopantogram (post-processing images from axial CT) shows an additional
nondisplaced fracture of the left parasymphysis (blue arrows).
Plain orthopantogram should not be used as a single imaging to look for mandibular
fractures. It is useful for tooth fracture, not for mandible.
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32. B
A
Mandibular Fractures with TMJ Dislocation
19-year-old woman in a rollover motor vehicle accident.
Axial CT image (A) shows ‘empty glenoid sign’ (red line) indicating right
temporomandibular joint dislocation. Image B in a more inferior slice reveals a fracture of
the right mandibular condyle (red arrow) with anterior medial displacement of the condyle
due to the pull of lateral pterygoid muscle. The left glenoid fossa is normal.
C = Left condyle of mandible
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33. Mandibular
Fractures with TMJ
Dislocation
Same patient as in previous
page.
3D image on right lateral
view makes it easier to
understand the fracture
site, dislocation and
orientation of the
fragment.
Red arrows = fracture of the
base of right condyle of
mandible
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34. Mandibular Fractures with Tooth Fracture
Young man in a motor vehicle accident.
Tooth fracture of ADA #29 is apparent (blue arrow) in this orthopantogram. However,
fracture of the right body of mandible is very subtle (red arrow) and may be detected only
retrospectively. This confirms that orthopantogram is not an appropriate imaging
technique to rule out or characterize mandible fractures.
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35. Mandibular Fractures with Tooth Fracture
Same patient as in previous page.
In this case, CT demonstrates comminuted fracture of the right body of mandible (red
arrow) and tooth fracture (blue arrow).
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36. Imaging Approach - Plain Film
 Friendly line (anterolateral antral wall of maxillary sinus)
 Both intact
 NO ZMC or LeFort fractures
 Blowout fracture
 Isolated fractures of lateral orbital wall, zygomatic arch
 One disrupted
 ZMC fractures
 Maxillary sagittal fracture (isolated sinus fracture)
 Both disrupted
 LeFort fractures
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37. Imaging Approach - CT
 Clear sinus sign (= all sinuses and mastoid are clear of fluid), there
are three possible facial fractures:
 Nasal bone fractures
 Isolated zygomatic arch fractures
 Mandible fractures
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38. Imaging Approach - CT
 Bloody sinuses
 Pterygoid plate fracture present - probable LeFort fracture
With fracture of lateral margin of nasal fossa = LeFort I

With fracture of inferior orbital rim = LeFort II

With fracture of zygomatic arch = LeFort III

 Maxillary wall fractures
 Orbital floors, NOE region fractures
 ZMC fractures
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39. Checklist for Facial
Radiograph/CT
 Treat life-threatening injury first (ABC of trauma)
 CT is more accurate, faster to do than plain films and can be
performed at the same time as trauma head CT
 Facial structures are quite symmetrical
 Do not stop searching when see one abnormality
 If suspect for more than simple nasal fracture, do CT
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40. Checklist for Facial
Radiograph/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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41. Checklist for Facial
Radiograph/CT
 Emergency in face injury
 Airway compromise due to severe soft tissue swelling, fracture
or obstructed foreign body
 Life threatening hemorrhage can be from nasal injury
 Facial fractures that compromise vision
 Orbital apex fracture may injure optic nerve, requiring urgent Rx
 Entrapment of intraocular muscle requires urgent Rx
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42.  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.
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