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 - 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. 

     Approximately one-third of Jefferson fractures are associated with other cervical spine fractures, with C2 associated fractures being the most common.

In this patient C2 Vertebral body fracture was noted.

  

 

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