Anatomy of the dens and its implications for fracture treatment: an anatomical and radiological study

  • J. Štulík
  • G. Hodasová
  • M. Podhráský
  • P. Nesnídal
  • P. Fojtík
  • O. Naňka
Original Article



The most common injuries to the upper cervical spine are fractures of the dens axis. Therefore, the purpose of our study was to answer three questions, namely (1) whether the size of the dens is adequate at all levels to accommodate two screws, (2) what the angle of the posterior tilt of the dens is in a healthy individual and (3) compare the measured variables between the sexes.


The cohort comprised 50 males and 50 females CT examination of the craniocervical junction. We measured the five diameters of the dens and posterior dens angulation angle (PDAA) and screw insertion angle (SIA). The same dimensions were measured in a control group, consisting of 40 non-pathological second cervical vertebrae specimens.


On CT scans, the mean PDAA was 162.7 degrees in males and 160.26 degrees in females; the mean SIA was 62.0 degrees in males and 60.2 degrees in females. On specimens, the mean PDAA was 169.47 degrees in males and 166.95 degrees in females; the mean SIA was 65.42 degrees in males and 64.47 degrees in females. All obtained values were higher in males; regardless of their measuring on either CT scans or specimens, differences between males and females were statistically significant (p < 0.05) in a, c, d and e values.


The values of our measurements correlate with the dimensions identified previously in other studies. Based on our clinical experience and measurements, we presume that two 3.5-mm screws can be inserted into the dens of all adult patients, except for those with pronounced anatomical anomalies. Posterior dens angulation angle is slightly larger than we expected. The dens is significantly larger in males almost in all measurement.

Graphical abstract

These slides can be retrieved under Electronic Supplementary Material.


C2 anatomy C2 fracture Dens fracture Posterior dens angulation angle Screw insertion angle 



This research was supported by Ministry of Health, Czech Republic—conceptual development of research organization, Motol University Hospital, Prague, Czech Republic 00064203—Jan Štulík. Petr Fojtík is grateful to Charles University for support in program of Specific University Research.

Compliance with ethical standards

Conflict of interest

On behalf of all authors, the corresponding author states that there is no conflict of interest.

Supplementary material

586_2018_5793_MOESM1_ESM.xlsx (17 kb)
Supplementary material 1 (XLSX 17 kb)
586_2018_5793_MOESM2_ESM.xlsx (14 kb)
Supplementary material 2 (XLSX 13 kb)


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Spinal Surgery, First Faculty of Medicine, Teaching Hospital MotolCharles UniversityPrague 5Czech Republic
  2. 2.Department of Imaging Methods, Second Faculty of Medicine, Teaching Hospital MotolCharles UniversityPrague 5Czech Republic
  3. 3.Orthopedic Department, First Faculty of Medicine and Central Military HospitalCharles UniversityPragueCzech Republic
  4. 4.Institute of Anatomy, First Faculty of MedicineCharles UniversityPrague 2Czech Republic

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