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Review article

The Dens: Normal Development, Developmental Variants and Anomalies, and Traumatic Injuries.

William T O'BrienPeter ShenPaul Lee
Department of Radiology, University of California, Davis, Sacramento, Department of Radiology, David Grant USAF Medical Center, Travis AFB, California, Department of Radiology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
Date of Submission: 25-May-2015, Date of Acceptance: 16-Jun-2015, Date of Web Publication: 30-Jun-2015.
Corresponding Author:
Corresponding Author

William T O’Brien Sr

Department of Radiology, David Grant USAF Medical Center, 101 Bodin Circle, Travis AFB, California ‑ 94535, USA.
E-mail: william.obrien.3@us.af.mil

Corresponding Author:
Corresponding Author

William T O’Brien Sr

Department of Radiology, David Grant USAF Medical Center, 101 Bodin Circle, Travis AFB, California ‑ 94535, USA.
E-mail: william.obrien.3@us.af.mil

DOI: 10.4103/2156-7514.159565 Facebook Twitter Google Linkedin


Accurate interpretation of cervical spine imagining can be challenging, especially in children and the elderly. The biomechanics of the developing pediatric spine and age-related degenerative changes predispose these patient populations to injuries centered at the craniocervical junction. In addition, congenital anomalies are common in this region, especially those associated with the axis/dens, due to its complexity in terms of development compared to other vertebral levels. The most common congenital variations of the dens include the os odontoideum and a persistent ossiculum terminale. At times, it is necessary to distinguish normal development, developmental variants, and developmental anomalies from traumatic injuries in the setting of acute traumatic injury. Key imaging features are useful to differentiate between traumatic fractures and normal or variant anatomy acutely; however, the radiologist must first have a basic understanding of the spectrum of normal developmental anatomy and its anatomic variations in order to make an accurate assessment. This review article attempts to provide the basic framework required for accurate interpretation of cervical spine imaging with a focus on the dens, specifically covering the normal development and ossification of the dens, common congenital variants and their various imaging appearances, fracture classifications, imaging appearances, and treatment options.
Keywords: Cervical Vertebrae, Dens Axis, Odontoid Process, Spinal Anatomy, Spinal Injuries

Cited in 11 Documents

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  6. Nicola Montemurro, Paolo Perrini, Vittoriano Mangini, Massimo Galli and Andrea Papini (2019) The Y-shaped trabecular bone structure in the odontoid process of the axis: a CT scan study in 54 healthy subjects and biomechanical considerations. :1. doi: 10.3171/2018.9.SPINE18396
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  8. Dimitrios S. Korres, Dimitrios G. Chytas, Konstantinos N. Markatos, Nicolaos E. Efstathopoulos and Vasileios S. Nikolaou (2017) The “challenging” fractures of the odontoid process: a review of the classification schemes. Eur J Orthop Surg Traumatol 27(4):469. doi: 10.1007/s00590-016-1895-3
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