A 14 yo female c/o neck pain in the ED, no radicular symptoms, numbness or weakness.  She is a soccer player who does head the ball frequently.  She has full range of motion, no neurological deficit,  and she is diffusely tender on the midline cervical spine.  A plain radiograph is completed.  What's the diagnosis?  Scroll down for answer

Diagnosis based on this radiograph : unilateral jumped facet versus congenital cervical spine abnormality

Unilateral facet dislocations

• mechanism often flexion rotation injury
• patients may present with head cocked to one side, in a "locked" position; could be misdiagnosed as torticollis
• patients may have symptoms of nerve root compression (25-73%) or spinal cord compression (8-48%)
• considered "stable" as the inferior articular facet of a vertebra slips above and anterior to the superior articular facet of the vertebra below and then is "locked" in place
• ED management involves cervical collar, advanced imaging, and spine specialty consultation. There are reports of successful closed reduction with sedation and traction in the ED, however evidence suggests better long term outcomes with surgical reduction over conservative management.  
• If the displacement is more than 50% diameter of the vertebral body consider bilateral facet dislocation 

This radiograph was initially interpreted as unliateral jumped facet.  CT, MRI, and orthopedic spine consultation were obtained.  The plain radiograph abnormality that was suggestive of unilateral jumped facet was deemed a congenital anomaly 

References

Santucci K. Chapter 20. Trauma. In: Shah BR, Lucchesi M, Amodio J, Silverberg M. eds. Atlas of Pediatric Emergency Medicine, 2e New York NY: McGraw-Hill; 2013 http://accessemergencymedicine.mhmedical.con/content.aspx?bookid=577$sectionid=42532506. Accessed October 17,2018

Payer M, Gluf W., Schmidt M. "Management of a Traumatic Unilateral Locked Facet of the Subaxial Cervical Spine."  Contemporary Neurosurgery, 26(1),  15 Jan 2004