is a Staff Radiologist in the Departamento de Radiologia,
Instituto Português de Oncologia, Porto, Portugal.
is a Professor and the Chairman of the Department of Radiology,
Thomas Jefferson University Hospital, Philadelphia, PA.
Approximately 2% of all hospital admissions in the United States
are due to facial fractures. Morbidity results when initial
diagnosis and management are inaccurate, delayed, or suboptimal.
High-resolution CT imaging has replaced conventional radiography
for the evaluation of facial trauma because of its widespread
availability and fast imaging capability. CT can also be performed
with less potentially hazardous positioning of injured patients.
Pre-sently, the necessity of a preliminary 4-film screening series
of radiographs is questioned. A single 30š occipitomental
radiograph can determine accurately which patients should have CT
Axial and coronal CT scans at ¾ 3 mm slice thickness are essential
for complete evaluation of the facial structures. Direct coronal CT
scanning is preferred, but if not feasible due to cervical injury,
thin-section axial helical scans should be performed that allow for
reformations in the coronal plane with optimal resolution.
A recent study undertaken in cadaver heads showed high
sensitivity and specificity for identifying clinically significant
fractures on reformatted images in trauma patients. The authors
suggested reformatted coronal images may be able to replace
dedicated direct coronal maxillofacial scanning that are precluded
in many patients due to suspected or associated cervical spine
Three-dimensional (3D) CT imaging is useful as an adjunct to
high-resolution thin-section CT and allows clinicians to visualize
the fracture fragments and their relationship to one another.
Three-dimensional images have been shown to add significantly in
the evaluation of severe facial trauma in 29% of patients.
These images appear superior in localization of complex fractures
involving multiple planes,
in the evaluation of fracture displacement, and in the assessment
of facial symmetry.
Also, 3D imaging is essential for fabrication of bone grafts used
in complex facial restorations.
However, this does not supplant two-dimensional (2D) imaging for
detection of fractures, especially for the deeper facial
structures. The role of MRI in the evaluation of facial trauma is
limited but may provide complementary information in special
circumstances, such as associated traumatic aneurysms, carotid
cavernous sinus fistula, etc.
Isolated fractures of the nasal pyramid represent approximately
50% of facial fractures.
The majority of nasal bone fractures involve the thinner distal
third of the nasal bones, and the nasal ethmoid complex remains
Nasal injuries may occur as isolated fractures or in conjunction
with other facial injuries.
The naso-orbital-ethmoid (NOE) fracture involves the nasal
bones, as well as the ethmoid sinuses and orbital rim. The anterior
nasal structures are usually displaced posteriorly into the
lacrimal bones and ethmoid sinuses. Changes in orbital volume with
consequent injury to the medial canthal ligament, cribriform
plates, nasofrontal duct, and nasolacrimal duct represent possible
Orbital fractures may be isolated or occur as a component of
more complex mid-face fractures, including the tripod fracture, the
Le Fort II and the Le Fort III fractures. Isolated orbital
fractures may involve one or more of the following: floor, the
lamina papyracea, roof, or lateral wall.
Orbital floor fracture (inferior blowout) (Figure 1) results
from a direct blow to the orbit by an object that is too large to
enter the orbit (ie, fist, baseball, etc.). The force of the blow
is absorbed by the orbital rim and is transmitted to the thinner
orbital floor, which usually fractures in the middle third near the
infraorbital canal. Furthermore, as the eye is pushed back, the
intraorbital pressure increases and this pushes the fracture
fragments down into the maxillary sinus. Usually, the orbital rim
and globe remain intact. These represent 3% to 5% of all mid-face
Herniation of orbital fat, inferior rectus muscle, or the inferior
oblique muscle can occur with muscle entrapment, resulting in
On CT, entrapment may be seen as an abrupt kink in the muscle as
opposed to a smooth prolapse through the site of fracture.
Traumatic subluxation of the globe into the maxillary sinus has
also been reported.
Orbital blowout fracture, where the fracture fragments show near
complete realignment, are called trap door fractures (Figure 2).
These are rather subtle and may be missed easily. There is a fine
fibrovascular network that binds the tendon sheath of the inferior
rectus muscle to the orbital floor periosteum and is prone to
disruption resulting in limitation of ocular motility due to
ischemic necrosis of the muscle. Failure to detect these fractures
early precludes surgical intervention and results in poor clinical
Fracture of the lamina papyracea (medial blowout) (Figure 3) may
occur either as an isolated fracture or in conjunction with an
orbital floor fracture. Since these different types of fractures
imply different surgical approaches, a classification based on
location and severity of injury has been proposed.
The mechanism of injury is similar to that of the inferior blowout
fracture. A medial blowout fracture may be present in as many as
50% of patients with orbital floor fractures.
Orbital emphysema, resulting from the ethmoid sinus fracture,
occurs commonly in patients with medial blowout.
Herniation of orbital fat and entrapment of medial rectus muscle
may occur. Indications for immediate surgery include definite
muscle entrapment and acute enophthalmos. Orbital soft-tissue
injuries include extraocular muscle entrapment, orbital hematoma,
rupture of the globe (Figure 4), dislocation of the lens (Figure
5), retinal or choroidal detachment, and optic nerve injury.
The blow-in fractures involve the orbital roof with inferior
displacement of fracture fragments into the soft tissues of the
orbit. In more than half of such cases, it is associated with
frontal sinus or skull fractures.
It has been reported that 14% to 29% of patients with blow-in
fractures show ocular injuries.
Zygomatic maxillary complex fractures (ZMC)
These are the second most common facial fractures.
Fracture lines extend in three directions, resulting in separation
of the zygoma from the orbit, maxilla, and the temporal bone
(Figure 6). Three components of the fracture include: 1) fracture
of the lateral orbital wall extending through the zygomaticofrontal
suture and the zygomaticosphenoid suture; 2) fracture of the
anterior lateral walls of maxillary sinus extending through the
zygomaticomaxillary suture; and 3) fracture through the zygomatic
arch dorsal to or through the zygomaticotemporal suture. The
infraorbital nerve is impaired in 94.2% of the cases.
In a simple ZMC injury, there is separation of the zygoma without
angulation, while a complex or ZMC fracture reveals rotation and/or
depression of the zygoma.
Zygomatic arch fracture
Depressed fracture of the zygomatic arch may be seen as an
isolated fracture. It usually shows two distinct fracture fragments
that are displaced medially and inferiorly. The fracture fragments
may impinge on the temporalis muscle or coronoid process of the
mandible and in some cases may alter dental occlusion.
Mid-face fractures (Le Fort classification)
Mid-face fractures are traditionally classified as Le Fort I,
II, and III types according to the portions of the midface involved
By definition, these fractures are bilateral and symmetrical, and
include extension through the pterygoid plates. Malocclusion of the
maxilla and mandible is found almost universally.
Le Fort I fractures result from a direct blow to the upper jaw
region and are characterized by detachment of the upper jaw with
tooth-bearing segment at a level just above the floor of the nasal
cavity. The fracture lines extend through the lower nasal septum,
the lower aspect of the maxillary sinuses, and the lower pterygoid
plates. The constellation of fractures results in a floating
Le Fort II fractures (pyramidal fracture) result from a direct
forceful blow to the central facial region. This results in
posterior displacement of the central mid-face. Fractures extend
through the nasion, separating the nose from the cranium. The
fracture lines extend on each side to involve the lacrimal bone,
medial orbital wall, orbital rim, orbital floor, anterior lateral
maxillary walls, and pterygoid plates in a pyramidal fashion. The
zygomatic arches remain intact.
Le Fort III fractures (craniofacial dysjunction) result in
complete separation of the facial skeleton from the skull base. The
fracture lines extend through the nasal ethmoid complex and extend
horizontally through the lacrimal bones, medial orbital wall, and
separate the frontozygomatic suture. These fractures extend across
the floor of the orbit to the inferior orbital fissure and the
pterygoid plates. The zygomatic arches are also fractured. These
patients are prone to complications such as cerebrospinal fluid
(CSF) rhinorrhea, hemorrhage, injury to the inferior orbital nerve,
and malocclusion. It is not unusual to find a combination of Le
Fort II and III fractures in the same patient. Le Fort III
fractures represent an extension of Le Fort II, and include
fractures extending through the zygomatic arch and the
The mandible is frequently fractured in association with severe
midfacial injuries, particularly those of the LeFort variety. The
mandible is fractured in more than one place 50% to 60% of the
The condylar fracture (Figure 8) is the most frequently undiagnosed
but is seen readily by coronal CT.
Frontal sinus fractures
Frontal sinus fractures may occur in isolation, or in
conjunction with mid-face fractures or cranial fractures. In the
vast majority of patients, fractures extend only through the
anterior table. Involvement of both the anterior and posterior
tables may be seen in 25% of the fractures (Figure 9).
Complications of fractures involving the posterior frontal sinus
wall include CSF leak, meningitis, pneumocephalus, etc. When facial
CT is performed for trauma, the absence of free fluid in a sinus
cavity virtually excludes a fracture of the sinus walls.
Temporal bone fractures
Temporal bone fractures are seen in 6% to 8% of patients with
severe head trauma.
Up to 30% of temporal bone fractures can be bilateral.
Typically, these fractures are described as longitudinal,
transverse, and mixed. The longitudinal fractures run along the
long axis of the petrous bone and account for approximately 80% of
all temporal bone fractures.
The transverse fractures run at right angles to the longitudinal
axis and account for about 20% of all temporal bone fractures.
Fractures with both components are described as complex or mixed.
Dahiya et al
have proposed a classification of temporal bone fractures with an
emphasis on the integrity of the otic capsule. This classification
offers the advantage of correlating radiographic utility and
stratification of clinical severity, including severity of Glasgow
Coma Scale scores and intracranial complications, such as
subarachnoid hemorrhage and epidural hematoma. The presence of an
otic capsule violating fracture is significantly more likely to be
associated with the latter two complications.
For complete evaluation, in addition to the fracture lines, special
note should be made of the following: 1) ossicular injury, 2)
facial nerve injury, 3) integrity of the tegmen tympani, 4) bony
labyrinth, 5) mastoid air cells, and 6) carotid canal.
Longitudinal fractures are the most common type of temporal bone
fractures and usually result from a lateral blow in the
temporo-mastoid region. The longitudinal fractures are subdivided
into an anterior and a posterior type. The anterior type course
along the anterior aspect of the squamous temporal bone and extend
along the roof of the external canal, tegmen tympani, and end in
the region of the geniculate ganglion. The posterior type course
along the posterior aspect of the squamous temporal bone and extend
through the mastoid air cells, posterior wall of the external
canal, through the tympanic cavity, and terminate in the region of
the geniculate ganglion. The inner ear structures are usually
spared because the fracture paths of least resistance are
Conductive hearing loss commonly accompanies the longitudinal
fracture, which may be transient due to hemotympanum or a ruptured
tympanic membrane. However, ossicular injury may occur in
approximately 50% of patients and result in persistent conductive
The most easily dislocated ossicle is the incus, resulting from the
disruption of the incudostapedial joint. The incudomallear
dislocation is less common (Figure 10). Facial nerve injury,
usually delayed and incomplete, occurs in only 10% to 20% of
patients with longitudinal fractures.
Transverse fractures are subdivided into a lateral and a medial
type, according to their relationship to the arcuate eminence. The
lateral type of fracture extends across the vestibule, basal turn,
and promontory of the cochlea, posterior and lateral semicircular
canals. The medial type of fracture extends across the internal
Transverse fractures are almost always accompanied with
sensorineural hearing loss, either due to transection of the
cochlear nerve or cochlear injury. Vertigo, dizziness, and tinnitus
may result from injury to vestibular nerves, the vestibule, the
semicircular canals, and the vestibular aqueduct associated with
transverse fractures. Facial nerve injury may occur in 30% to 50%
of patients, and immediate facial nerve paralysis is usually
indicative of nerve transection or severe compression by fracture
fragments. Delayed onset of facial nerve paralysis may be secondary
to fracture of the facial nerve canal, with associated contusion,
edema, or intraneural hematoma. A facial nerve hematoma can be
recognized as a high-signal intensity region on the unenhanced
T1-weighted images, and the damaged nerve segment can appear as a
thickened, strongly enhancing region on gadolinium-enhanced
Other complications of trauma include CSF otorhinorrhea,
perilymph fistula, posttraumatic meningocele, and
meningoencephalocele. Cerebrospinal fluid otorhinorrhea is usually
due to dural tear from fractures of the tegmen, most commonly as a
consequence of a longitudinal fracture. Disruption of the mastoid,
the internal auditory canal, and the petrous air cells are other
causes of otorhinorrhea. High-resolution CT cisternography is the
most useful study for the localization of the site of CSF leak.
Persistent vertigo may indicate a perilymph fistula. These result
from a tear either in the round window membrane or in the
ligamentous attachment of the stapedial footplate and are often
undetectable on CT. In the absence of a demonstrable fracture, the
presence of pneumolabyrinth is highly suggestive of this entity.
Internal carotid artery occlusion or pseudoaneurysm and jugular
vein-sigmoid sinus laceration or occlusion are other potential
complications that can occur when these vessels are in the path of
the fracture line.
The incidence of laryngotracheal trauma is estimated to be 1 in
30,000 emergency department visits in the United States.
These injuries result from motor vehicle collisions in the adult
population, and from accidents involving contact sports and hanging
type injuries in the young adult, adolescent, and pediatric
populations. A wide spectrum of injuries may be encountered.
High-resolution spiral CT imaging is the modality of choice, due to
its ability to obtain volumetric data acquisition and
retrospectively generate thin axial sections and, subsequently,
optimal multiplanar and 3D reconstructed images.
Blunt trauma to the larynx may result in soft-tissue injuries
with or without associated framework injuries.
If large enough or strategically located, endolaryngeal edema or
hematoma will produce a significant narrowing of the airway. It can
occur in three specific locations: in the pre-epiglottic space, in
the paralaryngeal space, and in the mucosal space.
Posttraumatic changes in the CT appearance of the false and true
cords may relate to the presence of edema, hematoma, laceration, or
avulsion. The thyroid and cricoid cartilages interact dynamically
to protect the airway from blunt injury.
The thyroid cartilage may reveal single or multiple fractures in
both the vertical and horizontal plane, depending on the degree of
the impact. Although the cricoid ring is shielded initially by the
anterior projection of the thyroid cartilage, it may reveal a
single median fracture or multiple paramedian vertically oriented
fractures with forceful impact and pose a danger of airway collapse
(Figure 11). The true cords may be paralyzed as a consequence of an
injury to the recurrent laryngeal nerve or dislocation of the
cricoarytenoid or cricothyroid joints. The former dislocation
typically manifests by an anterior and medial dislocation of the
involved arytenoid cartilage.
Frequently a paralyzed, paramedian vocal cord is present.
Dislocations of the cricothyroid joint manifest by widening of the
If the force is severe or low in the neck, complete
laryngotracheal separation may occur.
Separation usually occurs between the cricoid cartilage and the
first tracheal ring, resulting in displacement of the trachea
inferiorly and soft-tissue collapse into the airway, with
consequent airway obstruction. Other specific CT signs include
nonalignment of the laryngotracheal airway on serial CT images,
abrupt decrease or increase in airway caliber on sequential images,
the presence of a ragged or misshapen airway or the formation of a
The primary concern in the initial management of patients with
laryngotracheal trauma is the establishment and maintenance of an
Clinical examination is often limited in patients with trauma to
the head and neck region due to obscuration by overlying edema,
hemorrhage, and soft-tissue injury. High-resolution CT is essential
for accurate delineation of bony and soft-tissue injuries.