This document provides an outline and overview of imaging of facial trauma, focusing on nasal fractures and naso-orbital-ethmoidal fractures. It describes the relevant anatomy, mechanisms of injury, diagnostic imaging techniques including CT and x-rays, clinical findings, and complications. Radiologic examples are provided to demonstrate nasal septum fractures and NOE fractures from frontal blows. The goal is to aid in the diagnosis and management of these types of facial fractures.

1. Imaging of Facial Trauma
Part 2: Pathology
Rathachai Kaewlai, MD
Specialized in Body Imaging and Emergency Radiology
rathachai@gmail.com
January 2007
The author is willing to receive any input, comments and corrections,
Please do not hesitate to contact at the email address provided above. 1
Emergency Radiology: Imaging of Facial Trauma

2. Outline
• Facial and mandibular fractures
– Nasal fractures
– Naso­orbital­ethmoidal (NOE) fractures
– Frontal sinus fractures
– Orbital fractures
• Blowout fractures
• Blow­in fractures
• Floor fracture
• Orbital apex fracture
– Zygomatic fractures
• Zygomatic complex (ZMC) fractures
• Isolated zygomatic arch fracture
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Emergency Radiology: Imaging of Facial Trauma

3. Nasal Fractures
• Most common fracture of the facial bone
• Etiology: motor vehicle collisions (MVC) most common, followed
by assaults
• Relevant anatomy: Nasal pyramid consists of
– Nasal bones
• Inferior part of nasal bones is thinner than superior, more prone to fx
– Frontal processes of maxilla
– Nasal septum (superior = perpendicular plate of ethmoid, inferior =
vomer, anterior = quadrangular cartilage)
– Lateral cartilages (upper and lower lateral cartilages)
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Emergency Radiology: Imaging of Facial Trauma

4. Nasal Fractures
• Pattern of nasal fractures depend on direction of force
– Frontal direction (frontal blow)
• May cause a simple nasal fx
• Can be more severe with flattening of nose, septum and more
complicated fx such as naso­orbital­ethmoidal fx
– Lateral direction (lateral blow)
• May cause depression of ipsilateral nasal bone
• May also fracture contralateral nasal bone
• Interlocking of nasal bone and cartilage may occur; requiring open
reduction for adequate cosmetic result
– Inferior direction (blow from below)
• Usually with septum (quadrilateral cartilage, bony septum) fx and
dislocation
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Emergency Radiology: Imaging of Facial Trauma

5. Nasal Fractures
• Diagnosis:
– Made based on physical examination findings
• Visible bony deformity in displaced fx
• Laceration, ecchymosis, hematoma, mucosal tear and epistaxis in the
inner surface of the nasal cavity strongly suggest fx
– Presence of epistaxis and septal hematoma requires prompt
diagnosis and treatment
• Epistaxis can be life threatening
• Septal hematoma may lead to cartilage necrosis and resultant saddle
nose deformity
– Telecanthus is an indication of more severe injury, further
workup including CT scan is required
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Emergency Radiology: Imaging of Facial Trauma

6. Nasal Fractures
• Plain film radiography
– Plain film can miss up to nearly half of the patients with nasal
fractures
– Nasal bone series:
• Lateral nasal views (soft tissue technique)
• Water’s view
• CT
– CT better depicts fx, especially frontal process of maxilla.
Depressed fx of frontal process of maxilla can lead to facial
deformity if left untreated
– CT should be performed if there is more than a simple nasal
fracture on x­ray
– Presence of telecanthus prompts CT workup
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Emergency Radiology: Imaging of Facial Trauma

7. Nasal Fractures,
frontal blow
39­yo­man (cop vs.
robber) was punched from
the front
Comminuted bilateral
nasal bone fractures (red
arrows) with displaced
fragments.
N = nasal bone
M = Frontal process of maxilla
Black arrow = Intact
nasomaxillary suture
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Emergency Radiology: Imaging of Facial Trauma

8. Nasal Septum
Fractures
33­yo­man was
punched by a right­
handed person
S = Bony nasal septum
E = Ethmoid sinus
Sp = Sphenoid sinus
 = Orbital emphysema
(in this case, from
maxillary sinus fracture)
Fractures of the left frontal process of maxilla (red arrow) and right nasal bone (green
arrow) are noted. The fractures are displaced to the right, indicating the force of impact
from the left. The right­handed person hit the left side of the nose of the victim.
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Emergency Radiology: Imaging of Facial Trauma

9. Nasal Septum
Fractures
67­yo­man involved in
a motor vehicle
collision
S = Bony nasal septum
E = Ethmoid sinus
Blue arrows = Frontal
process of maxilla
 = Trapped air in
preseptal region
(anterior to the globe)
Deformity of the nose pointing toward the left. Angulation of the cartilagenous portion of
the nasal septum (red arrows). Blood in the nasal cavity is present as soft tissue density.
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Emergency Radiology: Imaging of Facial Trauma

10. Naso­orbital­ethmoidal (NOE)
Fractures
• Etiology:
– Forceful frontal blow to the central aspect of midface.
– Most common from motor vehicle collisions (MVC), followed by
assaults
• NOE fractures involve the central upper face, disrupting the
medial orbit, nose and ethmoid sinuses
• NOE fractures are distinguished from simple nasal
fractures by
– Posterior disruption of medial canthal region, ethmoids and
medial orbital walls
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Emergency Radiology: Imaging of Facial Trauma

11. Naso­orbital­ethmoidal (NOE)
Fractures
• Relevant anatomy:
– NOE complex consists of nasal, frontal, maxillary,
ethmoid, lacrimal and sphenoid bones
– Superior to NOE complex is anterior cranial fossa
– Lateral to NOE complex is globe
– Deep to NOE complex is optic canal and sphenoid
bone
– Center of NOE complex is interorbital space,
consisting of ethmoid sinuses, lacrimal drainage
system, nasofrontal ducts
– NOE fractures can injure significant
surrounding structure
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Emergency Radiology: Imaging of Facial Trauma

12. Naso­orbital­ethmoidal (NOE)
Fractures
• Relevant anatomy
– Medial canthal tendon
• A crucial soft tissue component of NOE complex
• Medial portion of orbicularis oculi, inserting to the medial orbital wall
• Acts as a suspensory sling for the globe and ensure close apposition of
the eyelid
• In NOE fractures, medial canthal tendon pulls the fragment laterally, or
(rarely) torn, causing telecanthus
• Helpful clinical signs to detect traumatic telecanthus
– Intercanthal distance > interpalpebral distance of the eyes
– Intercanthal distance more than one­half of interpupillary distance
– Clinically, the most obvious deformity is loss of nasal
projection in profile and apparent telecanthus
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Emergency Radiology: Imaging of Facial Trauma

13. Naso­orbital­ethmoidal (NOE)
Fractures
• Three types of NOE fractures
– Type I: Large fragment of medial orbit, medial canthal insertion is
intact
– Type II: Comminution of bones, fracture line does not extend into
area of medial canthal insertion
– Type III: Comminution of bones, fracture line extends into area of
medial canthal insertion
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Emergency Radiology: Imaging of Facial Trauma

14. Naso­orbital­ethmoidal (NOE)
Fractures
• Pertinent radiologic information
– Degree of comminution of medial orbital wall, especially in the
lacrimal fossa where medial canthus attaches
– Involvement of nasofrontal ducts require surgical obliteration of
frontal sinus to prevent frontal mucocele
– Extension
• Posterior extension to the optic canal
• Superior extension to the frontal sinus, intracranial structures
• Complications
– Persistent telecanthus
– Injury to lacrimal system
– Nasofrontal duct impingement
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Emergency Radiology: Imaging of Facial Trauma

15. NOE Fractures,
bilateral, type II or III
21­yo­man was assaulted
E = Ethmoid
M = Maxillary sinus
Sp = Sphenoid sinus
= Orbital emphysema
A Frontal blow to the nasion results
in a comminuted fracture
involving the medial walls of both
orbits (green circle), nasal bones
(green arrow) and frontal
processes of maxillae (red arrows)
as shown in image A. Blue arrows
indicate the attachment sites for
medial canthal tendons. Posterior
displacement (depression) of the
nasion is noted in image B.
B
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Emergency Radiology: Imaging of Facial Trauma

16. C D
3D images better depict degree of displacement and depression of the NOE fractures. The
fractures also extend to frontal sinuses (F). Comminuted fractures of bilateral nasal bones
(N) and frontal processes of maxillae (M). Small images on right lower corners represent
normal anatomy in the same projections. From radiological perspective, type II and II NOE
fractures may not be differentiated.
Radiologic description should comment on degree of comminution of medial orbital
wall especially in the region of lacrimal fossa, where the medial canthus attaches and
nasofrontal ducts locate.
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Emergency Radiology: Imaging of Facial Trauma

17. Frontal Sinus Fractures
• Etiology: motor vehicle collision (most common), followed by
high­impact sport related injuries
• Clinical
– Gross depression or laceration over supraorbital ridge,
glabella or lower forehead (most common finding on clinical
exam)
– Ophthalmologic evaluation may be necessary because up to
half of patients have orbital trauma
• Classification of fractures
– Location: anterior wall, posterior wall, or both
– Appearance: linear, comminuted, depressed or nondisplaced
• Isolated anterior wall fracture is most common
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Emergency Radiology: Imaging of Facial Trauma

18. Frontal Sinus Fractures
• Relevant anatomy
– Frontal sinus first appear 6­8yrs, fully pneumatized in adolescence.
– It can be asymmetric/partial incomplete pneumatized up to
20% of population
– Frontal sinus drainage via either nasofrontal duct located
posteriomedially in the sinus (the only drainage pathway of frontal
sinus ­ may be absent in general population) or in conjunction with
anterior ethmoid air cells. The nasofrontal duct, if present and
fractured, can be obstructed ­ leading to chronic drainage
complication
– Frontal sinus is closed to dura, frontal lobe, crista galli and
cribiform plate
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Emergency Radiology: Imaging of Facial Trauma

19. Frontal Sinus Fractures
• Indication for surgery
– Fracture potentially injures nasofrontal duct (fx involves base of
frontal sinus, medial to supraorbital notch)
– Depressed anterior wall ­ cosmetic deformity
– Posterior table fx with gross CSF leak, more than one table width
displacement
• Pertinent radiologic information
– Status of nasofrontal duct, posterior wall, frontal lobe injury
• Complication
– Early complication: frontal sinusitis (retained FB in sinus) leading to
meningitis, osteomyelitis, orbital abscess or brain abscess
– Late complication: mucocele, mucopyocele, delayed CSF leak
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Emergency Radiology: Imaging of Facial Trauma

20. Frontal Sinus Fractures
Two examples. Young
patients who were
assaulted.
Above: Isolated anterior
wall fracture (red arrows)
with hemosinus. Intact
posterior wall (blue arrow).
This type of depressed
fracture causes cosmetic
deformity
Below: Both anterior and
posterior table fractures
(red and green arrows),
which are nondepressed.
Pneumocephalus (white
arrow)
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Emergency Radiology: Imaging of Facial Trauma

21. Frontal Sinus Fractures
Scout CT: Asymmetrical haziness of the left frontal sinus (normal frontal sinus on
AP skull radiograph should have same density to the orbit) indicates hemosinus (red
arrow).
Axial CT: Fracture of the posterior wall of the left frontal sinus (green arrows) is
demonstrated. There is displacement of the fracture fragments into the sinus. Small
pneumocephalus is noted deep to the fracture. The patient also has anterior wall
fracture (not shown). Isolated posterior wall fracture is rare.
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Emergency Radiology: Imaging of Facial Trauma

22. Orbital Fractures
• Plain film radiography has false negative rate of 7­30%
• CT in axial, and coronal planes are essential to determine
presence of fractures and status of intraocular muscle
– Axial: medial, lateral wall fracture, entrapment of medial rectus
muscle
– Coronal: floor, roof fracture, entrapment of inferior rectus muscle,
fracture involving nasolacrimal duct
– Both are helpful for fx of optic canal, retro­orbital hematoma
• Two main types
– Blowout fractures
– Blow­in fractures
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Emergency Radiology: Imaging of Facial Trauma

23. Orbital Fractures
• Blowout fractures
– Bone is displaced away from the orbit
– May involve the roof, floor, and medial or lateral walls of the orbit
• Most common = floor
– If orbital rim is intact = ‘pure’ blow­out fracture (classic fx)
– Up to 30% have ocular injury
– Two proposed mechanism of injury
• Hydraulic mechanism: pressure on eyeball increases intraorbital
pressure, then the orbit ruptures at its weakest point (thin floor)
• Buckling mechanism: blow to orbital rim results in fx of orbital wall
– Clinical
• Enophthalmos, diplopia and hypoesthesia (infraorbital nerve
distribution). This can be obscured due to swelling
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Emergency Radiology: Imaging of Facial Trauma

24. Orbital Fractures
• Blowout fractures
– Pertinent radiologic information
• Appearance of inferior rectus muscle on coronal images
– Normal = oval shape
– Abnormal = round shape
• Location of inferior rectus muscle
– Abnormal = located below the expected level of orbital floor
• Abnormal inferior rectus can be
– Entrapped: muscle lies completely beneath or within the defect and
appears round on coronal images
– Hooked: portion of muscle lies within the defect
– Entrapment of inferior rectus in children can be easily missed, since
flexible bone springs back into place like a trap door, looking normal
at CT except for entrapped muscle beneath it
• This requires urgent Rx within 24­72 hours to minimize motility problem
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Emergency Radiology: Imaging of Facial Trauma

25. Orbital Blowout Fractures
Middle age patient involved in
motor vehicle collision
Coronal images (in bone and soft
tissue windows) show the defect
(red arrow) in the floor of the right
orbit with a small hematoma in the
right maxillary sinus (green arrow).
Light blue arrows point to the inferior
rectus muscle, where its inferior
portion (blue arrow) is hooked to the
defect. Clinically, the patient does
not have entrapment
O = Optic nerve
= Facial soft tissue edema
Clinical ophthalmologic
exam is required to confirm
or rule out evidence of
intraocular muscle
entrapment.
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Emergency Radiology: Imaging of Facial Trauma

26. Orbital Blowout Fractures
81­year­old woman fell from stairs
Intraorbital fat herniation (green arrow) through the defect in the floor of the left orbit. The
inferior rectus (blue arrow) is far from the site of fracture. 3D image shows intact orbital
rim (red arrows) indicative of ‘pure’ blow­out fracture.
O = Optic nerve, H = Hemosinus
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Emergency Radiology: Imaging of Facial Trauma

27. Orbital Fractures
• Blow­in fractures
– Bone is displaced into the orbit, intraorbital volume is decreased
– May involve the roof, floor, and medial or lateral walls of the orbit
– If orbital rim is intact = ‘pure’ blow­in fractures
– Clinical
• Exophthalmos (due to decreased orbital volume)
• Decreased visual acuity (eyeball trauma, optic neuropathy, fracture of
optic canal)
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Emergency Radiology: Imaging of Facial Trauma

28. Orbital Blow­in Fractures
80­year­old man fell onto his face.
Fractures of the floor of the left orbit (red arrow) displace superiorly into the
orbit. The medial rectus muscle (blue arrows) is pushed upward by the
fracture fragment. Intraorbital volume is further decreased by retroorbital
hematoma (blue star).
H = Hemosinus
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Emergency Radiology: Imaging of Facial Trauma

29. Orbital Fractures
• Orbital floor fractures
– Most common portion of orbit to sustain a fracture
– Usually associated with other complex midface fractures (ZMC,
LeFort II and LeFort III fractures)
– Can be linear, comminuted, or segmental
– Herniation of intraorbital contents
• Best seen in coronal projection
• What determines chance of herniation, entrapment?
– Size of fragment, degree of depression
• Inferior rectus muscle can be free, hooked, or entrapped
– Indications for surgery
• Involvement > 50% of the floor, combined floor and medial wall fx with
soft tissue herniation, significant enophthalmos (> 2mm), significant
diplopia
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Emergency Radiology: Imaging of Facial Trauma

30. Orbital Fractures
• Medial wall fractures
– Usually associated with other complex midface fractures
– Risk of medial rectus herniation (either hooked or entrapped) ­
relatively rare
• Orbital roof fractures
– Risk of brain herniation into the orbit (better seen with coronal
reformatted CT or MRI)
• Orbital apex fractures
– Emergent surgical cases if there is radiologic and clinical
evidence of optic nerve impingement
– May be associated with blindness
– May be associated with carotid artery injury (cavernous portion)
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Emergency Radiology: Imaging of Facial Trauma

31. Orbital Fractures
• Soft tissue injuries of the orbit
– Eyeball rupture
• Usually there is extrusion of vitreous (normal intraocular pressure is
higher than intraorbital pressure) ­ leading to ‘flat tire’ sign and
‘deepening’ of anterior chamber sign seen in CT
– Lens injury: subluxation, dislocation, traumatic cataract
• Zonular fibers hold lens in place to ciliary muscle. If torn (partial or
complete), subluxation or dislocation occurs
• Traumatic cataract (acute lens edema): affected lens has density 30HU
less than normal side
– Intraorbital hemorrhage
– Intraorbital foreign body
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Emergency Radiology: Imaging of Facial Trauma

32. Globe Rupture and Vitreous Hemorrhage
21­year­old man was assaulted.
Right globe rupture is evident by flattening of the posterior wall of the globe “flat tire
sign” (red arrow) and narrowing of the space between cornea and lens “deepening of
anterior chamber” (red line). = Vitreous hemorrhage
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Emergency Radiology: Imaging of Facial Trauma

33. Hemorrhage: Preseptal, Vitreous and Choroidal
Preseptal hemorrhage = bleeding in the space anterior to the globe (green arrows, line)
Vitreous hemorrhage = bleeding in the posterior chamber of the globe (red star), usually making
‘obtuse’ angle with the surrounding vitreous
Choroidal hemorrhage = bleeding in the choroid (white stars) along the wall of the globe
Blue arrows represent subcutaneous edema/hemorrhage.
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Emergency Radiology: Imaging of Facial Trauma

34. Traumatic Lens Dislocation
60­year­old man was found down.
Traumatic left lens dislocation (red arrow) is noted. Dislocation occurs due to tear of
zonular fibers normally surrounding the lens. Blue arrows point to normal lens at the
locations of zonular fiber attachment. The patient also has diffuse subarachnoid
hemorrhage (red stars) and multiple facial fractures.
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Emergency Radiology: Imaging of Facial Trauma

35. 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 the
fractures are depressed
• Masseter muscle arises from zygomatic arch
• Coronoid process is located underneath the
zygomatic arch
35
Emergency Radiology: Imaging of Facial Trauma

36. 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 has become separated from
its three areas of attachment
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Emergency Radiology: Imaging of Facial Trauma

37. 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
– Pertinent radiologic information
• 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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Emergency Radiology: Imaging of Facial Trauma

38. Zygomatic Fractures
• Isolated zygomatic arch fracture
– Etiology: direct blow by small object
– Commonly consists of 3 fractures:
• One at each extremity
• 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
38
Emergency Radiology: Imaging of Facial Trauma

39. Zygomatic Complex Fractures
60­year­old 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 ‘blow­out’
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
39
Emergency Radiology: Imaging of Facial Trauma

40. Zygomatic
Complex Fractures
Same patient as in
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).
40
Emergency Radiology: Imaging of Facial Trauma

41. Isolated Zygomatic Arch Fractures
23­year­old man was punched by a left­handed.
Classic zygomatic arch fractures occur in three sites along the arch. The
middle fracture causes fracture fragment depression. The depressed
fragments impinge on masseter muscle and can limit jaw movement.
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Emergency Radiology: Imaging of Facial Trauma

42. • The information provided in this presentation…
– Does not represent the official statements or views of the Thai
Association of Emergency Medicine.
– 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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Emergency Radiology: Imaging of Facial Trauma