Introductory Notes
     Most spinal cord injuries are attributed to trauma.  
Absence of radiographic findings does not exclude a 
spinal cord injury.  A substantial portion of spinal cord 
injuries in children (25% to 50%) have no radiographic 
abnormalities--SCIWORA (spinal cord injury without 
radiographic abnormalities).  Some patients with 
cervical spine injury may also have thoracolumbar 
lesions.  In the younger child, injuries to the cervical 
spine often involve the upper three vertebrae.

Pediatric Considerations
     Pediatric anatomy differs from the adult in several 
important ways, particularly in the ossification pattern of 
the cervicocranium (occiput-atlas-axis) and the normal 
laxity of the developing soft tissue structures of the 
cervicocranium.  These differences can lead to false 
positive interpretation as fractures, subluxations, and/or 
tumors etc. (Refer to Case 5 of Volume 1, Cervical 
Spine Malalignment - True or Pseudo Subluxation?, 
and Case 1 of Volume 5, Fever With Neck Stiffness . . . 
Rule Out Meningitis). 

Clinical Aspects
     The assessment of cervical spine injuries must first 
be a clinical evaluation.  Clinical and radiographic data 
should be interpreted  together to yield the most 
accurate assessment.
     Diagnostic strategies depend on whether the patient 
is conscious and can freely move his or her neck.  
Unconscious or poorly conscious patients should be 
examined radiographically while maintaining cervical 
spine immobilization since history and examination will 
be unreliable.
     A conscious patient with a significant cervical spine 
injury will complain of pain.  A significant cervical spine 
injury is not likely to be present in a patient without neck 
pain who is alert, not intoxicated, and lacks other painful 
injuries (that may distract neck pain).  Normal cervical 
range of motion is consistent with the absence of a 
cervical spine injury and such patients generally do not 
need any radiographs.

Anatomy
     In order to properly evaluate the radiographic 
images of the cervical spine, an understanding of the 
cervical spine anatomy is necessary to appreciate the 
structural organization that lends to spinal stability.  The 
vertebrae are bony building blocks connected  by 
ligamentous and muscular structures.  This resulting 
stable skeleton provides the scaffold for the soft tissue 
structures that communicate between the head and the 
thorax, the spinal cord being one of the most delicate 
and important.
     The cervical spine is made up of seven sequentially 
numbered cervical vertebrae, C1 through C7.  
Superiorly, C1 is connected to the occiput of the 
cranium.  Inferiorly, C7 is connected to the first thoracic 
vertebrae, T1.  The upper portion of the cervical spine, 
C1 and C2, together with the occiput is also referred to 
as the cervicocranium.  All vertebrae share many 
common features.  These will be reviewed along with 
features unique to the cervical vertebrae.  C1 and C2 
are atypical cervical vertebrae and will be treated 
separately. 

Vertebral Body
     The anterior and most easily identifiable structure of 
a vertebra is the vertebral body, also known as the 
centrum.  The body is the largest and appropriately the 
main weight-bearing structure of a vertebra.  The back 
of the body also forms the anterior border of the spinal 
canal.  

View C4.

     The three line diagrams on the left from top to 
bottom include an axial view, viewed from the top (Top), 
an anterior view (AP), and a lateral view (Lat).  The 
three photographs of C4 on the right from top to bottom 
include a view from the top (Top), a view from the 
bottom (Bottom), and an oblique view from the bottom 
(Bottom oblique).
     Identify the following structures on these diagrams 
and photos:
     SP - spinous process
     L - lamina (forms roof of the neural arch)
     P - pedicle (forms supports of the neural arch)
     SC - spinal canal 
     VB - vertebral body
     SAF - superior articular facet
     IAF - inferior articular facet
     TF - transverse foramen
     Gr - groove for spinal nerve (transverse process)
     U - uncinate process

     The neural arch is formed by the laminae, the base 
of the spinous process and the pedicles.  The pedicles 
are very short in the cervical spine.  The facet joints are 
formed by the inferior and superior facets such that the 
C4-C5 facet joint is formed by the inferior articular facet 
of C4 and the superior articular facet of C5.

     On a lateral film, the body is a rhomboid with the 
posterior portion slightly taller than the anterior portion.

View lateral C-spine view.

     The lateral view of a very young child is shown on 
the left compared to the lateral view of a teenager on 
the right.  Alignment is assessed by the integrity of lines 
drawn along:  1) the anterior borders of the vertebral 
bodies, 2) the posterior borders of the vertebral bodies 
and 3) the anterior borders of the vertebral arch's apex 
(spinolaminal line).  The facet joints should be clearly 
visible.

View identifying landmarks.

     The contour lines of alignment are shown.  Identify 
the following areas on the radiographs:
     F - facet joint
     SP - spinous process
     L - lamina
     Od - odontoid


     On an AP view, the lateral superior edges of the 
body form bilateral ridges, called the uncinate  
processes (U).

View AP C-spine view.

     A posterior view of the cervical spine is shown on 
the left.  An anterior view  is shown in the center.
     Axial compression can result in compression 
fractures which can lead to decreased vertebral body 
height or a burst fracture that fragments the vertebral 
body.  A strong lateral force can cause a shearing 
action and create fractures of an uncinate process.  
Hyperflexion and hyperextension may also result in 
teardrop fractures of the anterior superior or inferior 
corner of the body.
     Between the vertebral bodies are the intervertebral 
disks.  These function as shock absorbers.  As in the 
lumbar region, rupture of the annulus can lead to 
encroachment into the spinal canal.  The vertebral body 
also serves as the attachment site of the anterior and 
posterior longitudinal ligaments.  Tears in these 
ligamentous structures can result from displacement or 
extensive fractures of the vertebral body.  Without 
these ligamentous connections, the vertebral column is 
unstable.   

Neural Arch
     Posterior to the vertebral body is the neural arch 
(vertebral arch covering the spinal canal).  The neural 
arch refers to all the structures dorsal to the body.  The 
arch serves to protect the spinal cord, provide 
attachment sites for ligaments and muscles, and forms 
synovial joints that facilitate movement of the vertebral 
column.  The major structures that make up the arch 
include:  1) the pedicles, 2) the laminae, 3) the spinous 
process, 4) the articular processes and facets, and 5) 
the transverse processes. 

View C4.

Pedicles
     The pedicles ("little feet") form the supports of the 
neural arch as it is attached to the vertebral body.  In 
the cervical spine, the pedicles are short.  They project 
posteriorly (dorsally) from the body and form the lateral 
borders of the spinal canal.  Superior and slightly larger 
inferior vertebral notches above and below the pedicles 
form intervertebral foramina in the articulated vertebral 
column.  Through these foramina pass the cervical 
spinal nerves.

View lateral.

     On a lateral film, the pedicles appear as small 
connections between the body and the articular 
processes (see below).  On the AP view, the pedicles 
appear as small doughnut densities on the lateral upper 
portion of the vertebral body, just below the uncinate 
processes.  Fractures in this region can disrupt the 
spinal nerves or the spinal cord itself.

View AP.
  

Laminae
     The laminae (meaning "layers") form a roof over 
the neural arch, supported by the pedicles.  In addition 
to the obvious protective function, the laminae also 
serve as the site of attachment for the ligamentum 
flavum.  Because the laminae are thinner in the C-spine 
compared to other vertebrae, their relative radiolucency 
appears as an apparent gap between the posterior 
cortex of the articular facets and the anterior cortex of 
the spinous process (posterior aspect of the neural 
arch) on the lateral view.  In general, the laminae (L) 
are not easily appreciable on an AP view. 

View lateral.

Spinous Process
     The spinous process projects dorsoinferiorly from 
the point of union of the laminae.  Unique to the typical 
cervical vertebrae, the spinous processes of C3 through 
C6 are typically bifid at the tips.  The spine of C7 is an 
easily visible surface landmark called the vertebra 
prominens.  The spinous processes are the site of 
attachment for a number of ligamentous and tendinous 
structures.  The major ligaments associated with the 
spine include the interspinous and supraspinous 
ligaments as well as the ligamentum nuchae.  A number 
of intrinsic muscles of the spine as well as large back 
muscles such as the trapezius, the levator scapularis,  
and the rhomboids are attached to the cervical spinous 
processes.  Excessive load on these muscles may 
result in avulsion of the spinous processes of C6 and 
C7, commonly known as the clay shoveller's fracture.  
This fracture is more commonly found in adults.

View lateral.

     On a lateral view, the spinous processes appear as 
triangular extensions.  The anterior border with the 
laminae (spinolaminal line) is an easily visible feature 
marking the posterior border of the vertebral canal 
(spinal canal).  On an AP view, the spinous processes 
appear as a midline density superimposed on the 
vertebral body.  The bifid nature of some of the cervical 
spines can be easily appreciated in this view.

View AP.

Articular Processes and Articular Facets
     The articular processes are cylindrical structures at 
the junction of the pedicles and the laminae.  Like the 
pedicles, articular processes also delimit the lateral 
margins of the spinal canal.  The articular facets, the 
oblique elliptical ends of the cylinders, are higher 
anteriorly and lower posteriorly.

View articular facets of C4.

     Capsular articular ligaments join adjacent inferior 
and superior articular facets of successive vertebrae to 
form synovial joints.  Strong rotary forces can stretch or 
tear these ligaments resulting in unilateral or bilateral 
dislocated facets.

View lateral.

     On a lateral view, the articular processes are 
rhomboidal in shape and superimposed upon one 
another.  Unlike the vertebral body which slopes 
downward anteriorly, the articular processes slope 
sharply downward posteriorly.  They appear 
superimposed on the spinal canal.

View oblique view.

     The skeletal model on the left shows variability in 
the intervertebral disk spacing due to poor positioning of 
the model bones during photography.  This oblique view 
shows the intervertebral foramina formed by the inferior 
notch of the pedicle of the vertebrae above and the 
superior notch of the pedicle of the vertebrae below. 

Transverse Processes
     The transverse processes project outward 
anteroinferiorly from the pedicles like half-cylindrical 
scoops.

View C4.

     Along the grooved portion of the transverse 
process pass the ventral rami of the cervical nerves.  
The dorsal rami pass more posteriorly.  In the middle 
of the transverse process is a foramen for the vertebral 
artery as it courses upward toward the foramen 
magnum.  Lesions in this region can damage the 
nerves of cervical and brachial plexi as well as 
compromise the arterial supply of the posterior brain.

The Cervicocranium
     The articulations between the occiput, the atlas 
(C1), and the axis (C2) are highly specialized to allow 
the extensive range of motion of the head upon the 
neck.  As such, C1 and C2 differ sufficiently from the 
typical vertebrae that they deserve special mention.

View odontoid view.

     The atlas (C1) articulates superiorly with the 
occipital bone.  The occipital bone forms the base of the 
cranium, and articulation with the cervical spine is via 
the pair of large convex occipital condyles situated on 
either side of the anterior half of the foramen magnum.  
The brain stem becomes the spinal cord as it leaves the 
cranium through the foramen magnum.  Anterior to the 
foramen magnum is an upward incline to the dorsum 
sellae called the clivus.  The posterior aspect of the 
foramen magnum is in-line with the posterior arch of C1 
and C2 (the spinolaminar line).
     Lacking a body, the atlas is essentially a ring with 
prominent articular processes that are appropriately 
called lateral masses.  The lateral masses divide the 
ring into a smaller anterior and a larger posterior arch.  

View C1-C2 cross section CT scan.

     On the inner aspects of the lateral masses are 
tubercles for the transverse ligament that run between 
these tubercles.  The concave superior facets articulate 
with the convex condyles of the occipital bone, while the 
larger inferior facets (of C1) articulate with C2.  
Because the atlas lacks a body, the lateral masses are 
the major weight bearing structures, and a compression 
force (axial load) can result in a bursting fracture of the 
ring of C1.  The upper CT image shows such fracture of 
the C1 ring.

View odontoid view.

     On an open-mouth odontoid view, the lateral 
masses are easily visible as trapezoidal wedges.  The 
anterior and posterior arches are superimposed over 
the odontoid process.
     Radiographically, the surfaces of the anterior 
atlantoaxial gap are parallel to each other and the 
distance is less than 5 mm in a child.  Widening of this 
space can be a result of a transverse ligament tear, 
allowing unstable motion between the two bones.

View lateral.

     On a lateral view, the atlas is a simple ring structure 
seen edge on.  The lateral masses are superimposed 
on the odontoid process of C2 and are difficult to 
identify.  The inner aspect of the anterior arch can be 
easily appreciated, as can the inner aspect of the 
posterior arch.  Note that the anterior arch articulates 
with the anterior aspect of the odontoid, while the 
posterior arch forms the very first posterior border of 
the vertebral canal.
     The most prominent feature of C2 (axis) is the 
odontoid process, also called the dens.  Both names 
refer to its resemblance to a tooth.  The odontoid 
process projects superiorly from the body of the axis. 
Articular processes centered around the odontoid have 
smooth superior facets that facilitate rotational 
articulation within the atlas.  The inferior facets are 
more posterior and in-line with the articular processes 
of the rest of the cervical vertebrae area.  On a lateral 
view, the axis appears much like a typical cervical 
vertebra, however, it is easily identified by the odontoid 
process projecting vertically from the body and the large 
and wide spinous process.

View odontoid view.

     On an open-mouth odontoid view, the axis is shaped 
like a fat bowling pin with wings.  The odontoid and the 
body form the bowling pin, and the articular processes 
are the wings.
     The articulation of the odontoid and the atlantal 
anterior arch is unique.  Anteriorly, it is between the two 
bones; posteriorly, the dens articulates with the 
transverse ligament that is attached to the inner 
aspects of the atlantal lateral masses.  The spinal cord 
travels in the space posterior to the transverse 
ligament.

View C1-C2 cross section CT scan.

     The upper image is a CT scan axial image through 
the ring of C1.  The odontoid process is visible 
anteriorly in the ring.  The transverse ligament is not 
easily visible on this CT cut; however, it is posterior to 
the odontoid.  The spinal cord is visible in the posterior 
portion of the ring of C1 (the spinal canal).  Note the 
fracture in the anterior aspect of C1.  The gap in the 
posterior portion of C1 is a growth plate.  Compare this 
CT image with the bony model of C1 and C2.

View open mouth odontoid view.

     Developmentally, the bodies of the axis and the 
dens arise from separate ossification centers. The 
odontoid (dens) itself has three ossification centers.  
There are two columnar centers, forming the body of 
the odontoid that typically fuse before birth, and a 
third center at the tip of the odontoid.  During infancy, 
before the tip of the odontoid has ossified, the 
superior end of the odontoid may have a cleft in it 
radiographically.  The odontoid of children may have a 
separate ossification center at the tip of the 
odontoid--the os terminale.  A finding of a fragment at 
the superior-most tip of the odontoid may be due to a 
fracture or it may a normal ossification pattern.
     The most common normal radiographic pattern 
mistaken for an odontoid fracture is the subdental 
synchondrosis.  This is a linear lucency at the base of 
the dens.  The dens usually fuses with the body of C2 
somewhere between ages 3 and 6 years.  However, a 
thin, sclerotic "scar" of the synchondrosis may be 
appreciable on the lateral view for many years 
thereafter.
     Normal laxity of the soft tissues of the 
cervicocranium in the developing pediatric patient can 
make radiologic interpretations more difficult.  Laxity of 
the prevertebral tissues can resemble abscesses, 
hematomas, or tumors, particularly if the film is taken in 
exhalation or in flexion.  Laxity of the transverse atlantal 
ligaments -- spanning from the dens to the inner aspect 
of the lateral masses of the atlas -- allow greater range 
of motion between these two bones.  This, in addition to 
the cartilaginous (non-ossified) nature of the outer 
layers of the odontoid, accounts for an increased 
anterior atlanto-odontoid (atlantodental) interval of 3-5 
mm in infants. In addition, the margins of the anterior 
atlanto-odontoid interval can lose their parallelism 
during neck flexion.  These pediatric norms can 
resemble atlantoaxial subluxation.   Furthermore, laxity 
of the ligamentous structures around C3 can also 
resemble subluxation at the C2-C3 or C3-C4 junctions.

Radiographic Views
     The three most common views employed in the 
emergency department are:  1) the lateral view, 2) the 
AP view, and 3) the AP open mouth odontoid.  The 
lateral view can be taken as a cross-table lateral while 
the patient is still on a spine board in the emergency 
department.  The anteroposterior views often require 
transporting the patient to the imaging department.  
Below is an introduction to reading these three common 
views.

Lateral neck
     The lateral cervical spine radiograph is the most 
useful view.  As many as 80-90% of cervical spine 
injuries can be detected on the lateral view alone.  The 
quality of the film image obtained should be assessed.  
All cervical vertebrae, C1-C7, and the top part of T1 
should ideally be visible.  It is important to be able to 
count all 7 cervical and one thoracic vertebrae since the 
most common lesions occur at the upper and lower 
ends of the cervical spine.  The most commonly missed 
lesions occur at the C7-T1 junction simply because it is 
not shown on the film.
     To assess C-spine alignment, four imaginary lines 
can be drawn on the lateral film; which aid evaluation of 
vertebral alignment:  1) anterior longitudinal line, 2) 
posterior longitudinal line, 3) posterior facet margins 
(not shown on diagram), and 4) spinolaminar line.

View lateral.

     The anterior and posterior longitudinal lines simply 
correspond to the locations of the anterior and posterior 
longitudinal ligaments.  The spinolaminar line 
demarcates the posterior limits of the spinal canal.  
These lordotic contours should be smooth and without 
step-offs.
     The neck is normally positioned with lordosis 
(extension).  In adults, a straight C-spine (lack of 
lordosis) indicates the presence of muscle spasm and a 
possible occult fracture.  In children, the absence of 
lordosis is commonly seen.  When positioned on a 
spine board, the large occiput of most children positions 
their neck in a straight (without lordosis) or in a flexed 
alignment.  This is common and does not necessarily 
indicate the presence of a significant injury.  However, it 
does make interpretation of the radiographs more 
difficult since such poor positioning may cause 
artifact radiographic abnormalities.   
     Proper positioning of the atlantoaxial bones with the 
occiput can be assessed by noting the alignment of two 
imaginary lines.  First, extension of a line down the 
slope of the clivus should point to the superior end of 
the dens (the os terminale).  The posterior margin of the 
foramen magnum should be in line with the 
spinolaminar line.  Such an alignment places the 
foramen magnum in-line with the spinal canal, this 
corresponds to the junction of the brain stem and the 
spinal cord.
     Dislocation of articular facets or a fractured 
vertebrae may result in a discontinuity of the contours 
of these lines with implications of instability and 
decreased patency of the spinal canal lumen resulting 
in impingement of the spinal cord.
     Widening of the retropharyngeal space is a sign of 
injury to either soft tissue or the adjacent vertebrae.  
The retropharyngeal space (essentially, the 
pre-vertebral soft tissue space) should be roughly half 
the width of a vertebral body.  Fractures of the C-spine 
can result in hemorrhaging into the retropharyngeal 
space, resulting in widening of this soft tissue space on 
the lateral neck view. 
     The spacing of the facet joints, intervertebral 
spaces, and interspinous gaps can provide hints to the 
integrity of the mechanical stability of the connections 
between vertebrae.  The width of these spaces should 
be fairly constant between sequential vertebrae.  The 
articular surfaces should be parallel to each other.  In 
addition, the spinous processes are generally 
equidistant from each other but converge toward a point 
at the base of the posterior neck.  Pathologically, 
increased spacing often results from tearing of the 
supporting ligaments.  Increased interspinous 
distances, "fanning," is often associated with a posterior 
longitudinal ligament tear.  Decreased spacing could 
lead to invagination of connective tissue into the spinal 
canal.
     The major features of all vertebra should be 
examined.  The height of each vertebral body should be 
fairly constant from C3 through T1.  A slight decrease in 
height of a vertebral body may be a compression 
fracture.  A difference of greater than 25% can occur 
only if the posterior intervertebral ligaments are torn.  
The pedicles, facets, and laminae of each vertebra 
should be superimposed upon each other in a properly 
taken radiograph.  Doubling of facets and articular 
columns should be examined for evidence of unilateral 
or bilateral dislocated facets. 
     The cortical surfaces of each vertebra should be 
scrutinized for steps, breaks, or abnormal angulations.  
Blurred edges may result from fractures or dislocations.  
Often the tendons and ligaments are stronger than the 
bones themselves, and tear-drop shaped pieces of 
bone could be avulsed by a strong force acting on the 
anterior longitudinal ligament.  In the clay shoveller's 
fracture (spinous process fracture), a downward force 
on the supraspinous ligament shears most of the C6 or 
C7 spinous process off its base. 

AP View
     The AP view is helpful in evaluating the vertical 
alignment of the spinous processes and the 
visualization of the vertebral body from the AP 
perspective.  This view is also important in evaluating 
lateral displacement of fractures or entire vertebrae.

View AP.

     Typically, in this view, the mandible and occiput are 
superimposed over C1 and C2, and sometimes the 
upper portions of C3 may be obscured.  An adequate 
film should clearly show the vertebral column from C3 
to T1.
     Spinous processes should be aligned in the midline 
and be generally equidistant from one another.  
Misalignment of the spinous processes may suggest a 
dislocation or a fracture of an articular surface. 
     Increased spacing between spinous processes or an 
apparent missing spinous process in this view may 
suggest a fractured spinous process, as in the clay 
shoveller's fracture (spinous process fracture).  A 
widened gap may also be due to a tear of the posterior 
longitudinal ligament, resulting in "fanning" as seen on a 
lateral radiograph.  
     The trachea is easily visualized in this view.  
Disruption of tracheal radiolucency may also indicate 
nearby lesions. 
     The intervertebral spaces should be evaluated for 
uniformity from one vertebral pair to another.  The 
spaces should be of similar distances apart and the 
articular surfaces should be fairly parallel to each other.  
Dislocations and ligamentous tears may produce 
widened or narrowed joint spaces in an AP view.
     Lastly, the vertebrae should be evaluated for 
fractures.  The cortical surfaces should be continuous 
and well defined.  Each vertebral body should be 
rectangular and of similar size.  The uncinate 
processes (U), bilateral raised lips on the superior 
surface of the vertebral bodies, are most easily 
evaluated for fractures from this AP view.  

Open-Mouth Odontoid View
     The AP open-mouth odontoid radiograph is used to 
evaluate the cervicocranium from another perspective.  
It is most valuable in assessing the relationship 
between the lateral masses of the atlas and the axis.  
The junction between C1 and C2 should be clearly 
visible.  Visibility of the entire odontoid process is of 
secondary importance.

View odontoid view.

     From this perspective, left and right symmetry is 
most helpful in evaluation.  The two atlantal lateral 
masses should be equidistant from the dens, and the 
articular surfaces of the atlantoaxial lateral masses 
should be in perfect alignment.  The inferior facets of 
the atlantal (C1) lateral masses should be parallel to 
and aligned with the upper facets of the axial (C2) 
lateral masses (white arrows point to the lateral margin 
of the facet joint).  Lateral displacement of one or both 
of the atlantal lateral masses (black arrow) is 
suggestive of a Jefferson fracture in which the ring of 
C1 is fractured, bursting it open displacing the lateral 
masses outward.
     The lateral masses should also be scrutinized for 
unequal size.  In rotary subluxation, the atlas is turned 
such that one lateral mass is farther than the other from 
the radiographic film and may appear larger.  However, 
rotary subluxation is best confirmed on a CT scan.
     Laxity of ligamentous attachments surrounding the 
odontoid and incomplete ossification of the odontoid 
may allow up to two-thirds of the anterior atlantal arch 
to be above the tip of the odontoid process.
     Fractures of the odontoid are common and can be 
seen on lateral and open-mouth odontoid views.  These 
fractures are classified according to the location of the 
fracture.  Type I is an oblique fracture through the upper 
portion of the odontoid.  It should be noted that 
sometimes the upper incisors can obscure portions of 
the upper odontoid and simulate a Type I fracture.  
Type II fractures occur at the base of the odontoid 
where it joins the body of C2.  This is the most common 
odontoid fracture.  Unfortunately, this is also the 
location of the subdental synchondrosis.  

     NOTE:  While it is not unusual for the odontoid to be 
tilted posteriorly, it should NOT be tilted anteriorly.  This 
is more indicative of an odontoid fracture.  Widening of 
the subdental synchondrosis coupled with anterior tilting 
of the odontoid are highly indicative of an odontoid 
fracture.

     A Type III odontoid fracture extends into the 
vertebral body of C2.
     The odontoid image shows three open mouth 
odontoid radiographs on the right.  The upper 
radiograph shows the odontoid well.  However, the 
lateral margins of the lateral masses of C1 and C2 are 
obscured by the patient's lower teeth, making it 
impossible to assess the lateral alignment of the C1-C2 
facet joints.
     The middle image shows a bursting ring fracture of 
C1 with outward displacement of the C1 lateral masses 
(black arrow).  The lower image shows normal 
alignment of the C1-C2 facet joints.  The white arrow 
points to the lateral margin of the facet joint.

Other Special Views
     In addition to the standard three views (lateral, AP, 
odontoid), other radiographic views can aid in obtaining 
a better perspective on a suspected lesion.
     Swimmer's View:  Recall that an adequate lateral 
film should reveal all seven cervical vertebrae and 
upper T1.  Typically, downward traction on the arms will 
produce the adequate visualization in most cases.  
Should the C7/T1 junction still be obscured, a 
swimmer's view can be obtained by elevating the arm 
closest to the film.  This posture yields a slightly oblique 
view of the vertebral column, but moves the shoulder 
joint above the C7/T1 junction.  C7/T1 can easily be 
seen in this view; however, it is often overlapping with 
dense soft tissue and the bones of the shoulder.

View swimmer's view.

     In this swimmer's view, note that the lower cervical 
spine can be seen, but in this case, it is still not optimal 
since C7 is still not visualized.  

     Oblique Projections:  The oblique views provide 
good visualization of the posterior structures of the 
vertebral column, such as the intervertebral foramina 
and articulation of the facets.  They are particularly 
helpful in evaluating suspected unilateral facet 
dislocations since only one half of the facets and 
intervertebral foramina are viewed at a time.  The 
foramina are also best visualized on these views.

View oblique views.

     Lateral Flexion and Extension Views:  The flexion 
and extension views are obtained on a conscious 
patient who can actively bend their neck.  Care must be 
taken in obtaining these views as there is risk of further 
displacement.  In appropriate circumstances, these 
views may be particularly helpful in excluding 
ligamentous injury and potential instability.  Some 
physicians have found the flexion view invaluable in 
detecting occult posterior ligamentous injuries resulting 
from hyperflexion. 

References
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Emergency Radiology: Cervical Spine - II.  BMJ 
Oct1993:307(2):855-859.
      3.  Ellis GL.  Imaging of the Atlas (C1) and Axis 
(C2).  Emergency Medicine Clinics of North America. 
1991;9(4):719-731.
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Diagnositic Radiology - 11: The Cervical Spine in 
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1978.
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