summary Pseudosubluxation of the cervical spine is a physiologic radiographic variant due to the horizontal nature of the cervical facet joints found in young children Diagnosis is made radiographically with a relative anterior translation of C2 on C3 (up to 4 mm) that resolves with cervical spine extension Treatment is observation as the condition resolves when the cervical facet joints become more vertical with age Epidemiology Incidence ~20% of children admitted for polytrauma will demonstrate this incidental finding no associations with gender, trauma, intubation status, or injury severity have been demonstrated Demographics seen in children <8 y/o Anatomic location C2 on C3 is the most common location C3 on C4 is the second most common location Etiology Pathophysiology caused by the horizontal nature of the facet joints at younger ages facet joints become more vertical with age Imaging Radiographs recommended views lateral radiograph with flexion and extension views findings reduction of subluxation with extension x-rays absence of anterior soft-tissue swelling (usually seen with a traumatic cause) measurements Swischuk's line spinolaminar line drawn from spinolaminar point on C1 to C3 spinolaminar point on C2 should be within 1.5 mm of the spinolaminar line helpful to differentiate pseudosubluxation from a true injury Differential True traumatic subluxation factors that support pseudosubluxation as opposed to true traumatic subluxation include: reduction of subluxation with neck extension spinolaminar line within 1.5mm of C2 no history or physical findings of significant trauma absence of anterior soft-tissue swelling true traumatic subluxation may be caused by Hangman's fracture Treatment Nonoperative observation indications pseudosubluxation outcomes no association with increased morbidity or mortality