Fractures and Dislocations: C1 (Jefferson Fracture)

Jefferson Fracture  (C1 Burst Fracture)  -  Unstable

Fractures of the posterior arch = 67%, 

• 25% associated with C7 Spinous process fx, 

• 15% with hangman’s Fx’s

C1 or atlas fractures consist of unilateral or bilateral vertical fractures through the neural arch. Compression force is applied to C1 that usually results from a blow to the vertex of the head (driving injury).

Treatment:  Halo placement for 3 months

Displacement of lateral masses.

CT should be obtained (if available) for defining full extent of fracture and detecting fragments in spinal cord.

More than 7mm outward displacement of the lateral masses means tear or avulsion of the transverse ligament.

    
C1 Burst, Jefferson Fracture, Ondontoid View

Findings:  The open mouth ondontoid view shows displacement of the lateral masses of C1 approx 9mm.  Remember >2mm bilateral offset of C1 Relative to C2 is always abnormal,  <1-2mm or unilateral offset can be due to head rotation/tilt.

C1 Burst, Jefferson Fracture, CT Scan

This section written by:

LCDR Ron Boucher, MC, USN
LT Hugh McSwain, MC, USN

With some assistance from:

CDR Michael Puckett, MC, USN
ENS Robert Post, MC, USNR