FIGURE 112.18 A: Posterior cervical line of Swischuk A line is drawn from the cortex of the spinous process of C1 to the cortex of the spinous process of C3 Relationship of the line to cortex of the spinous process of C2 is noted If the line is situated more than mm anterior to the cortex of the spinous process of C2, underlying cervical pathology should be present This line should be used only with anterior displacement of C2 on C3 B: Pseudosubluxation of C2 on C3 with normal posterior cervical line in a 2-year-old child Note apparent widening of prevertebral soft tissue (asterisk ) C: Abnormal posterior cervical line with an underlying hangman’s fracture (star indicates anterior cortex of spinous process) Actual offset is mm (C : Reprinted with permission from Swischuk L Emergency Radiology of the Acutely Ill or Injured Child 2nd ed Baltimore, MD: Williams & Wilkins; 1986:562–563.)