A 7-year-old male was diving off a ledge when he 
landed head first in shallow water.  He was pulled 
semiconscious from the water by lifeguards.  While 
maintaining his airway, the lifeguards placed the patient 
in full C-spine immobilization.  When the patient 
became more alert, he complained of pain to his upper 
neck region.  Paramedics transported the patient to the 
ED.
     Upon arrival, the patient is awake, alert, cooperative, 
and in C-spine immobilization.  His vital signs are 
normal, and the neurologic exam is nonfocal.  He 
continues to complain of upper neck pain.
     A cross table lateral neck radiograph is obtained.

View lateral neck radiograph.

     With the patient in in-line manual immobilization, the 
cervical collar is released, and the cervical spine is 
palpated.  The exam is remarkable for tenderness in 
the upper cervical spine region.  The lateral neck 
radiograph is suggestive of mild prevertebral soft tissue 
widening.
     AP and odotoid open mouth views are obtained.  
The AP view is normal.

View the odontoid views.
 
     This is a poorly taken radiograph.  The ideal open 
mouth odontoid view should have the odontoid centered 
in the mouth with the lateral masses of C1 clearly 
visible.  However, emergency physicians are commonly 
presented with such poorly positioned radiographs 
because it is often very difficult to properly position a 
patient, with neck pain.  It is often impossible to obtain a 
satisfactory open mouth view in very young children 
who are not cooperative.  In such patients, a CT scan 
may be necessary.  Avoid the pitfall of misinterpreting a 
poorly positioned odontoid view.  In this radiograph, 
only the lower lateral corners of the lateral masses of 
C1 are visible.  However, this should be sufficient to 
make the diagnosis of a Jefferson fracture.

View the alignment of the lateral masses.

     The lateral margins of the lateral masses (inferior 
articular facets of C1) should align with the lateral 
margins of the structures below it (superior articular 
facets of C2).  The space between these two facets is 
the atlanto-axial joint.  In  this radiograph, the lateral 
masses of C1 are displaced outward, indicating a 
"bursting" of the ring of C1 (the Jefferson Fracture).

     A Jefferson fracture is a compression and/or 
bursting fracture of C1.  This unstable fracture is the 
result of a direct blow to the vertex of the head (axial 
compression load), either from a fall or from an object 
striking the vertex of the head.  Neurologic injury is rare 
but can occur if there is involvement of C2.
     The axial load to the head (skull and occipital 
condyles) focuses the stress on the C1 lateral masses, 
causing them to be compressed against the superior 
articular facets of C2.  In the most classic cases, the 
damage to C1 usually occurs in four places, with 
fractures in two sites anteriorly and two sites 
posteriorly.  The transverse diameter of the spinal canal 
is increased as a result of the displacement of the 
lateral masses.  When C1 is fractured in less than four 
places, transverse ligament tears are common and can 
lead to more instability.  If the transverse ligament 
remains intact, there will be no neurologic deficits, and 
the lateral cervical spine X-ray may appear normal.  If 
the transverse ligament is ruptured, C1 will move 
forward on C2, and the spinal cord will be compressed.
     Radiographic findings can show bilateral 
displacement of the C1 lateral masses when compared 
to the C2 articular pillars.  There can be unilateral 
lateral displacement of the C1 lateral mass if there is no 
movement of the opposite lateral mass.  Routine 
radiographs sometimes may not show evidence of a 
fracture.
     The open mouth odontoid view will best show the 
lateral displacement of the C1 lateral masses.  Neck 
rotation can cause false positive radiographs.  A 
pseudo-Jefferson fracture has the radiographic 
appearance of a true Jefferson, but is the result of 
cartilage artifact and the increased growth of the atlas 
in comparison to C2.  CT of the upper cervical spine is 
indicated if there is any suggestion of a Jefferson 
fracture.
     Approximately one-third of Jefferson fractures are 
associated with other cervical spine fractures, with C2 
associated fractures being the most common.


     A repeat open mouth odontoid view of our patient is 
obtained.

View repeat odontoid view.

     The lateral (outward) displacement of the lateral 
masses is clearly visible in this radiograph.

View anatomic outlines for above.

     The lateral masses are clearly displaced.



View normal odontoid radiographs.

     These two odontoid views show the normal 
alignment of the lateral masses and the superior facets 
of C2 below them.


View our patient's CT scan.

     This CT image of our patient shows the unilateral 
fracture of the "ring" of C1.  The odontoid process is 
visible.  The spinal cord is faintly visible posterior to the 
odointoid within the neural arch.


References:
     Cornelius R, Leah J.  Imaging evaluation of cervical 
spine trauma.  Neuroimaging Clinics of North America 
1995;5(3),451-463.
     Fesmire F, Luten R.  Pediatric cervical spine.  
Journal of Emergency Medicine 1989;7:133-142.
     Roberge R.  Facilitating cervical spine radiography in 
blunt trauma.  Emergency Medicine Clinics of North 
America 1991;9(4):733-742.
     Daffner R.  Evaluation of cervical vertebral injuries.  
Seminars in Roentgenology 1992;27(4); 239-253.
     Gerlock A, et al.  The cervical spine in trauma.  WB 
Saunders Company, Philadelphia, 1978.