By: Terry Yochum, DC, DACBR, Fellow, ACCR and Michael S. Barry, DC, DACBR
This young adult male patient was in a motor vehicle accident, where he received a severe hyperextension-hyperflexion injury. A complete set of conventional radiographs was performed and an abnormality was detected on the lateral projection. Can you identify the pathology?
Figure 1. Diagnosis: Hangman’s fracture of C2. Observe the radiolucent defect present at the posterior vertebral body line of C2 representing a fracture of the pedicle-laminar junction.
Fractures of the neural arch of the axis are one of the most common injuries of the cervical spine. Up to 40% of axis fractures are hangman’s fractures. They are usually the result of automobile accidents in which there is abrupt deceleration from a high speed, though the fracture occurs during hyperextension. The distribution of the fracture is similar to that resulting from judicial hanging. This has prompted the term hangman’s fracture; though this is actually a misnomer, since the hangman does not receive the fracture. It should more accurately be called the hangee’s fracture.
The fracture occurs as a bilateral disruption through the pedicle of the axis, sometimes referred to as the pars interarticularis. The fracture lines are best seen on CT or the lateral view just anterior to the inferior facet, usually in association with anterior displacement of C2 upon C3. This displacement is usually persistent following osseous union, a sign of previous injury, which should be recognized. Occasionally the axis body will be flexed and distracted superiorly. Prevertebral hemorrhage is common, increasing the retropharyngeal interspace that may compromise the adjacent airway. This may produce dysphagia clinically. Up to 25% have an accompanying fracture, usually of the atlas. An avulsion of the anterior-inferior corner of the vertebral body (teardrop fracture) often occurs simultaneously.
There is a surprising lack of neurological findings in fractures of the neural arch of the axis due to the large spinal canal at this level. Extension of the fracture into the transverse foramen may precipitate vertebral artery injury.
About the Authors
Dr. Terry R. Yochum is a second generation Chiropractor and a cum laude graduate of the National College of Chiropractic, where he subsequently completed his radiology specialty. He is a Diplomate of the American Chiropractic Board of Radiology and served as its vice-president and president for seven years (1983–1990).
Dr. Michael S. Barry is a 1988 cum laude graduate of Palmer College of Chiropractic. He completed a three-year radiology residency at Logan College of Chiropractic following two years of clinical practice in Las Vegas, Nevada. He received his diplomate in radiology from the American Chiropractic Board of Radiology in 1992.