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Indications
Who needs radiographic studies of the cervical spine?
Indications for X-ray are:
1. Mental status less than alert or intoxicated
2. Reports neck pain
3. Midline neck tenderness
4. Neurologic signs and symptoms
5. Distracting injury (i.e. painful injuries elsewhere, e.g. extremity fractures)
Not all trauma patients with a significant injury need c-spine films. Criteria for excluding
cervical spine fractures on a clinical basis are: no neck pain, no neck tenderness on
palpation, having full, painless, active range of motion of c-spine, no history of loss of
consciousness, no mental status change, no neurologic deficit from neck injury, and no
distracting symptoms. If patient meets all these criteria, cervical spine injury is excluded
on clinical basis and the cervical collar may be removed.
Question: A patient arrived at the ED on backboard and a cervical collar. He has a blood
alcohol level of 0.2. He does not complain of any neck pain. Shoud he get a complete
cervical series? (push the button for answer)

Plain Films

Plain films provide the quickest way to survey the cervical spine. An adequate
spine series includes three views: a true lateral view (which must include all
seven cervical vertebrae as well as the C7-T1 junction), an AP view, and an
open-mouth odontoid view. These three views do not require the patient to move
his neck, and should be obtained without the removal of the cervical collar.

The Lateral View
The single most important radiographic
examination of the acutely injured cervical
spine is the horizontal-beam lateral

radiograph that is obtained before patient is
moved. This film should be obtained and
examed before any other films are taken.
All 7 cervical vertebrae and C7-T1 junction
must be visualized because the
cervicothoracic junction is a common place
for traumatic injury.
Visualization of C7-T1 may be limited by
the amount of soft tissue in the shoulder
region and can be enhanced by:
1. traction on arms if no arm injury is
present, or,
2. swimmer's view (taken with one arm
extended over the head).
Repeat lateral views with the cervical collar
removed may also help in clarifying subtle
abnormalities.
The lateral view is obtained as follows:

AP and Odontoid Views
The complete radiographic examination includes AP and open-mouth views.
If there are no obvious fractures or dislocations on the lateral view and the patient's
condition permits, then proceed with the AP and the open-mouth views.
It is important to obtain technically adequate films. The most frequent cause of
overlooked injury is an inadequate film series. Patient should be maintained in cervical
immobilization, and plain films should be repeated or CT scans obtained until all
vertebrae are clearly visible.
The AP view and Odontoid view are obtained as follows:

Flexion and Extension Views

What if no fracture is seen on initial films and pain is present?
Flexion and extension views may be used if a pure soft tissue injury is
suspected or an injury of questionable stability is noted. The patient should
perform the flexion and extension voluntarily. Flexion/extension views are
absolutely contraindicated in documented unstable injuries.


CT
Up to 20 % of fractures are missed on conventional radiographs. CT can help.
CT scan is not mandatory for every patient with cervical spine injury. Most injuries can
be diagnosed by plain films. However, if there is a question on the radiograph, CT of the
cervical spine should be obtained. CT scan are particularly useful in fractures that result
in neurologic deficit and in fractures of the posterior elements of the cervical canal (e.g.
Jefferson's fracture) because the axial display eliminates the superimposition of bony
structures.
The advantages of CT are:
1. CT is excellent for characterizing fractures and identifying osseous compromise of the
vertebral canal because of the absence of superimposition from the transverse view.
The higher contrast resolution of CT also provides improved visualization of subtle
fractures.
2. CT provides patient comfort by being able to reconstruct images in the axial, sagittal,
coronal, and oblique planes from one patient positioning.
The limitations of CT are:
1. difficult to identify those fractures oriented in axial plane (e.g. dens fractures).
2. unable to show ligamentous injuries.
3. relatively high costs.
At the University of Virginia, the CT protocol for cervcial spine trauma to rule out fracture
or dislocation is as follows: patient is put on a supine position in the CT scanner. Patient
is scaned from top of the vertebral body above the fracture or question of fracture to
bottom of the vertebral body below the fracture with slice thickness of 1.5 mm and 1.5

mm spacing. Sagittal and coronal reconstructions are done in all cases. Click here to
see an example of coronal reconstruction.

MRI

MRI is indicated in cervical fractures that have spinal canal involvement, clinical
neurologic deficits or ligamentous injuries. MRI provides the best visualization of the soft
tissues, including ligaments, intervertebral disks, spinal cord, and epidural hematomas.
The advantages of MRI are:
1. excellent soft tissue constrast, making it the study of choice for spinal cord survey,
hematoma, and ligamentous injuries.
2. provides good general overview because of its ability to show information in different
planes (e.g. sagital, coronal, etc.).
3. ability to demostrate vertebral arteries, which is useful in evaluating fractures
involving the course of the vertebral arteries.
4. no ionizing radiation.
The disadvantages of MRI are:
1. loss of bony details.
2. relatively high cost.
At the University of Virginia, the protocol for MRI in cervical spine trauma follows five
sequential scans: T1 turbo spin echo in sagittal plane, Turbo T2 in sagittal plane, 2D
flash in sagittal plane, 2D flash in axial plane and T1 turbo spine echo in axial plane.
Here is an example of a MRI image of the cervical spine demostrating a ligamentous
injury. Notice that the spinal cord is also very well delinated. A dens fracture is not
obvious on the lateral film, but is clearly revealed on MRI.

Interpretation

It is important to approach a cervical spine film series in a stepwise fashion. One
can follow an easily remembered mnemoic AABCDS. On each film, sequentially

evaluate adequacy, alignment, bone, cartilage, disc, and soft tissue.
A adequacy,
A alignment,
B bone,
C cartilage,
D disc, and
S soft tissue.

The Lateral View

The lateral view is the most
important film of all.
Interpretation follows the
mnemonic AABCDS.
First, is the film Adequate?
An adequate film should
include all 7 vertebrae and C7-
T1 junction. It should also have
correct density and show the
soft tissue and bony structures
well.

Alignment

Assess four parallel lines. These are:
1. Anterior vertebral line (anterior
margin of vertebral bodies)
2. Posterior vertebral line (posterior
margin of vertebral bodies)
3. Spinolaminar line (posterior margin

of spinal canal)
4. Posterior spinous line (tips of the
spinous processes)
These lines should follow a slightly
lordotic curve, smooth and without
step-offs. Any malalignment should
be considered evidence of ligmentous
injury or occult fracture, and cervical
spine immobilization should be
maintained until a definitive diagnosis
is made.
Sometimes, misalignment may be
physiological.
Subluxation
Pseudosubluxation

Atlanto-occipital Alignment

Atlanto-occipital alignment
The anterior margin of the foramen
magnum should line up with the dens.
A line projected downward from the
dorsum sellae along the clivus to the
basion should point to the dens.
The posterior margin of foramen
magnum should line up with the C1
spinolaminar line.
The ratio of Basion - spinolaminar line
of C1 to Opisthion - posterior cortex of
C1 anterior arch normally ranges from

0.6 to 1.0, with the mean being 0.8. A
ratio greater than 1.0 implies anterior
cranio-cervical dislocation.

Bony Landmarks

Trace the unbroken outline of each
vertebrae (including Odontoid on
C2). The vertebral bodies should line
up with a gentle arch (normal
cervical lordosis) using the anterior
and posterior marginal lines on the
lateral view. Each body should be
rectangular in shape and roughly
equal in size although some
variability is allowed (overall height
of C4 and C5 may be slightly less
than C3 and C6) . The anterior
height should roughly equal posterior
height (posterior may normally be
slightly greater, up to 3mm).


Bony Landmarks
Pedicles project posteriorly to support the
articular pillars, forming the superior and inferior
margins of the intervertebral foramen. The left
and right pedicels should superimpose on true
lateral views. If fracture is suspected, get
oblique views or CT.

Facets: the articular pillars are osseous masses
connected to the posterolateral aspect of
vertebral bodies via the pedicles. The facet
joints are formed between each lateral mass.
On the lateral view, the lateral masses appear
as rhomboid-shaped structures projecting
downward and posterior. "Double cortical lines"
results from slight obliquity from lateral
projection. The distance of the joint space
should be roughly equal at all levels.
Lamina: the posterior elements are seen poorly
on the lateral film. They are best demostrated by
CT.
Spinous process: generally get progressively
larger in the lower vertebral bodies. The C7
cervical spine is usually the largest.

Cartilaginous Space

The Predental space (distance from dens to C1 body) should not measure
more than 3 mm in adults and 5mm in children. If the space is increased, a
fracture of the Odontoid process or disruption of the transverse ligament is
likely. If fracture is suspected, CT should be obtained. If ligamentous
disruption is suspected, a MRI should be obtained.

Disc Spaces

Disc spaces should be roughly
equal in height at anterior and
posterior margins.

Disc spaces should be
symmetric.
Disc space height should also be
approximately equal at all levels.
In older patients, degenative
diseases may lead to spurring
and loss of disc height.

Soft Tissue Space
Preverteral soft tissue swelling is
important in trauma because it is usually
due to hematoma formation secondary to
occult fractures. Unfortunately, it is
extremely variable and nonspecific.
Maximum allowable thickness of
preverteral spaces is as follows:
Nasopharyngeal space (C1) - 10 mm
(adult)
Retropharyngeal space (C2-C4) - 5-7 mm
Retrotracheal space (C5-C7) - 14 mm
(children), 22 mm (adults). Soft tissue
swelling in symptomatic patients should
be considered an indication for further
radiographic evaluation. If the space
between the lower anterior border of C3
and the pharyngeal air shadow is > 7
mm, one should suspect retropharyngeal
swelling (e.g. hemorrhage). This is often
a useful indirect sign of a C2 fracture.
Space between lower cervical vertebrae

and trachea should be < 1 vertebral body.

Soft Tissue Swelling
Some fractures can be very subtle, and soft tissue swelling may be the only sign of
fracture. In this case, the lateral view shows only slight soft tissue swelling anterior to
C2, and no obvious fracture is seen. On the subsequent CT, a type III dens fracture
(fracture of the dens and extends into the body of C2) is demostracted.

The AP View

Alignment on the A-P view should be
evaluated using the edges of the
vertebral bodies and articular pillars.
The height of the cervical vertebral
bodies should be approximately equal
on the AP view.
The height of each joint space should
be roughly equal at all levels.
Spinous process should be in midline
and in good alignment. If one of the
spinous process is displaced to one
side, a facet dislocation should be
suspected.

The Odontoid View
First, assess if the film is Adequate.
An adequate film should include the entire
odontoid and the lateral borders of C1-C2.
Then, examine the Alignment.
Occipital condyles should line up with the

lateral masses and superior articular facet of
C1.
The distance from the dens to the lateral
masses of C1 should be equal bilaterally (see
figure below). Any asymmetry is suggestive of
a fracture of C1 or C2 or rotational
abnormality. It may also be caused by tilting of
the head, so if the vertebrae is shifted in on
one side, then it should be shifted out on the
other side.
The tips of lateral mass of C1 should line up
with the lateral margins of the superior
articular facet of C2. If not, a fracture of C1
should be suspected.
Finally, examine the Bony Margins.
the Odontoid should have uninterrupted
cortical margins blending with the body of C2.




Mechanism of Injury

The cervical spine may be subjected to forces of different directions and
magnitude. The most common mechanisms of cervical spine injury are
hyperflexion, hyperextension and compression.


Hyperflexion refers to
excessive flexion of the neck

in the sagital plane. It results
in disruption of the posterior
ligament. A common cause of
hyperflexion injury is diving in
shallow water, which may
result in flexion tear drop
fracture.

Hyperextension refers to
excessive extension of the neck in
the sagital plane. A common cause
of hyperextension injury is hitting
the dash board in MVA, which may
result in Hangman's fracture.