Bilateral Locked Facets:  Unstable

This results from extreme flexion of head and neck without axial compression.

It occurs with subluxation and locking of both facets, usually due to hyperflexion injury.  

All ligamentous structures at the level of injury are disrupted.  

There is anterior displacement of the dislocated segment at least 50% of the AP diameter of the vertebral body. 

Over 90% of these patients will have neurological Injury.

     
Bilateral Jumped Facets at C5

    
Bilateral Locked Facets at C5 

Findings:  Severe anterolisthesis of the involved Vertebral body (Grade II-III).  Both of the inferior facets of the involved vertebral body are anteriorly locked on the superior facets of the lower vertebral body.  There is no abnormal rotational subluxation, only listhesis and hyperflexion at this site.

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