Pseudosubluxation of Cervical Spine

  • Etiology: Physiologic ligamentous laxity usually at C2-C3 and less often at C3-C4 in older children
  • Imaging:
    — Less than 2 millimeters 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 millimeters of posterior cervical line and therefore if deviated less than 2 millimeters it is consistent with pseudosubluxation and if deviated greater than 2 millimeters it is indicative of true subluxation
  • DDX: Fracture or dislocation of cervical spine
  • 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.