Pseudosubluxation of Cervical Spine

Etiology: physiologic ligamentous laxity usually at C2-C3, less often at C3-C4 in older children
Imaging: < 2 mm of subluxation at C2-C3 is OK, assess by posterior cervical line which is line drawn from C1-C3 and which touches anterior aspect of posterior arches – anterior aspect of posterior arch of C2 should come within 1-2 mm of posterior cervical line and therefore if deviated < 2 mm it is consistent with pseudosubluxation and if deviated > 2 mm it is indicative of true subluxation
DDX: fracture / dislocation
Complications: none
Treatment: none
Clinical: usually not seen after 7 years

Radiology Cases of Pseudosubluxation of Cervical Spine

Radiograph of pseudosubluxation of the cervical spine — Lateral radiographs of the cervical spine in flexion (left) show anterior subluxation of the C2 vertebral body on the C3 vertebral body which reduces on extension (right) and is now in normal alignment.