- Fracture of C2 pars interarticularis: This fracture is typically through the pars interarticularis, although in children it may be the odontoid epiphysis instead.
- Hyperextension injury: In both adults and children, a hangman’s fracture is due to a hyperextension and distraction force.
- Must be differentiated from pseudosubluxation: In children, it is important to differentiate from a pseudosubluxation, a condition that can be seen in up to 40% of children younger than 8 years at C2-3 and 14% at C3-4 (7).
- Swischuk’s Line:This line is from the anterior cortical surface of the arch of C1 to the anterior cortical surface of the spinous process of C3.7. The anterior cortical surface of C2 should be on or within 1.5 mm of the line. A hangman’s fracture is suspected when it is >1.5 mm behind it. X-ray must be true lateral to evaluate.