Pediatric dens anatomy and its implications for fracture treatment: an anatomical and radiological study



Separation of C2 growth plates and dens fractures are the most common types of injuries to the axis (C2) in children. Operative treatment of these injuries with the use of direct osteosynthesis requires a profound knowledge of detailed anatomy and dimensions of the axis. The main issue addressed by the study was the age at which the size of the dens is adequate at all levels to accommodate two screws, and the size of the posterior dens angulation angle (PDAA) in a healthy child in individual age periods.


Dimensions and angles of the dens and C2 in individual age categories in both boys and girls were measured in a series of 203 CT scans of individuals 0–18 years old and on anatomical specimens (42 samples). In addition, 5 histological series of this region from the fetal period were reviewed.


Dimensions of the dens gradually increase with age, with a considerable acceleration during growth spurt periods that are different in boys and girls. PDAA is markedly changing with age; in the fetal period, the dens shows a slight anterior angulation which gradually transforms into posterior angulation, as early as between 4 and 6 years of age. The screw insertion angle changes accordingly.


During growth, there occur changes in PDAA that should be respected in evaluation of transformation of anterior into posterior angulation, as shown by imaging methods. Dens dimensions theoretically allow insertion of two 3.5 mm screws as early as from the age of 1 year.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5


  1. 1.

    Babu RA, Arivazhagan A, Devi BI et al (2016) Peculiarities and patterns of cervical spine injuries in children and adolescents: a retrospective series of 84 patients from a single institute. Pediatr Neurosurg 51:1–8.

    Article  PubMed  Google Scholar 

  2. 2.

    Fassett DR, McCall T, Brockmeyer DL (2006) Odontoid synchondrosis fractures in children. Neurosurg Focus 20:E7.

    Article  PubMed  Google Scholar 

  3. 3.

    Fulkerson DH, Hwang SW, Patel AJ, Jea A (2012) Open reduction and internal fixation for angulated, unstable odontoid synchondrosis fractures in children: a safe alternative to halo fixation? J Neurosurg Pediatr 9:35–41.

    Article  PubMed  Google Scholar 

  4. 4.

    Tokunaga S, Ishii Y, Aizawa T et al (2011) Remodeling capacity of malunited odontoid process fractures in kyphotic angulation in infancy: an observation up to maturity in three patients. Spine 36:E1515–E1518.

    Article  PubMed  Google Scholar 

  5. 5.

    Huber H, Ramseier LE, Boos N (2010) Open mouth digital reduction of an odontoid synchondrosis fracture: a case report. J Pediatr Orthop 30:115–118.

    Article  PubMed  Google Scholar 

  6. 6.

    Godard J, Hadji M, Raul JS (1997) Odontoid fractures in the child with neurological injury. Direct anterior osteosynthesis with a cortico-spongious screw and literature review. Childs Nerv Syst 13:105–107.

    CAS  Article  PubMed  Google Scholar 

  7. 7.

    Wang J, Vokshoor A, Kim S et al (1999) Pediatric atlantoaxial instability: management with screw fixation. Pediatr Neurosurg 30:70–78.

    CAS  Article  PubMed  Google Scholar 

  8. 8.

    Castellana C, Kósa F (1999) Morphology of the cervical vertebrae in the fetal-neonatal human skeleton. J Anat 194:147–152.

    Article  PubMed  PubMed Central  Google Scholar 

  9. 9.

    Ogden JA (1984) Radiology of postnatal skeletal development. XII. The second cervical vertebra. Skelet Radiol 12:169–177.

    CAS  Article  Google Scholar 

  10. 10.

    Çokluk C, Aydın K, Rakunt C et al (2006) The borders of the odontoid process of c2 in adults and in children including the estimation of odontoid/body ratio. Eur Spine J 15:278–282.

    Article  PubMed  Google Scholar 

  11. 11.

    Lee HJ, Kim JT, Shin MH et al (2015) Quantification of pediatric cervical spine growth at the cranio-vertebral junction. J Korean Neurosurg Soc 57:276–282.

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  12. 12.

    Koebke J, Saternus K-S (1986) Inclination of the odontoid process in children and adults—an anatomical and functional investigation. In: Wenker H, Klinger M, Brock M, Reuter F (eds) Spinal cord tumors experimental neurosurgery neurosurgical intensive care: advances in neurosurgery, vol 14. Springer, Berlin, pp 165–169

    Chapter  Google Scholar 

  13. 13.

    Tubbs RS, Wellons JC, Blount JP et al (2003) Inclination of the odontoid process in the pediatric Chiari I malformation. J Neurosurg 98:43–49.

    Article  PubMed  Google Scholar 

  14. 14.

    Ladner TR, Dewan MC, Day MA et al (2015) Posterior odontoid process angulation in pediatric Chiari I malformation: an MRI morphometric external validation study. J Neurosurg Pediatr 16:138–145.

    Article  PubMed  Google Scholar 

  15. 15.

    Štulík J, Hodasová G, Podhráský M et al (2019) Anatomy of the dens and its implications for fracture treatment: an anatomical and radiological study. Eur Spine J 28:317–323.

    Article  PubMed  Google Scholar 

  16. 16.

    Baumann F, Ernstberger T, Neumann C et al (2015) Pediatric cervical spine injuries: a rare but challenging entity. J Spinal Disord Tech 28:E377–E384.

    Article  PubMed  Google Scholar 

  17. 17.

    Piatt JH, Grissom LE (2011) Developmental anatomy of the atlas and axis in childhood by computed tomography. J Neurosurg Pediatr 8:235–243.

    Article  PubMed  Google Scholar 

  18. 18.

    Gore PA, Chang S, Theodore N (2009) Cervical spine injuries in children: attention to radiographic differences and stability compared to those in the adult patient. Semin Pediatr Neurol 16:42–58.

    Article  PubMed  Google Scholar 

  19. 19.

    Karwacki GM, Schneider JF (2012) Normal ossification patterns of atlas and axis: a CT study. AJNR Am J Neuroradiol 33:1882–1887.

    CAS  Article  PubMed  Google Scholar 

  20. 20.

    Hosalkar HS, Greenbaum JN, Flynn JM et al (2009) Fractures of the odontoid in children with an open basilar synchondrosis. J Bone Joint Surg Br 91:789–796.

    CAS  Article  PubMed  Google Scholar 

  21. 21.

    Rusin JA, Ruess L, Daulton RS (2015) New C2 synchondrosal fracture classification system. Pediatr Radiol 45:872–881.

    Article  PubMed  Google Scholar 

  22. 22.

    Gupta R, Narayan S (2015) Sublaminar wiring for odontoid synchondrotic fracture stabilization in a 4-year-old: a case report. Childs Nerv Syst 31:2185–2187.

    Article  PubMed  Google Scholar 

  23. 23.

    Labbe J, Peres O, Leclair O et al (2016) Posterior C1–C2 fixation using absorbable suture for type II odontoid fracture in 2-year-old child: description of a new technique and literature review. J Pediatr Orthop.

    Article  PubMed  Google Scholar 

  24. 24.

    Bapuraj JR, Bruzek AK, Tarpeh JK et al (2019) Morphometric changes at the craniocervical junction during childhood. J Neurosurg Pediatr 24:227–235.

    Article  Google Scholar 

  25. 25.

    Krmpotić-Nemanić J, Keros P (1972) Functional significance of adaptation of dens axis in the human. Verh Anat Ges 67:393–397

    PubMed  Google Scholar 

Download references


Supported by Ministry of Health, Czech Republic—conceptual development of research organization, Motol Univesity Hospital, Prague, Czech Republic 00064203—Jan Štulík. Petr Fojtík and Lucie Salavcová are grateful to Charles University for support in program of Specific University Research.

Author information




All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by GG, MB (CT scans) and LS, PF, ON (anatomical specimen). The first draft of the manuscript was written by JŠ and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

Corresponding author

Correspondence to Ondřej Naňka.

Ethics declarations

Conflict of interest

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

Ethics approval

We certify that the study was performed in accordance with the ethical standards as laid down in the 1964 Declaration of Helsinki and its later amendments.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Štulík, J., Geri, G., Salavcová, L. et al. Pediatric dens anatomy and its implications for fracture treatment: an anatomical and radiological study. Eur Spine J 30, 416–424 (2021).

Download citation


  • Pediatric C2 anatomy
  • Developmental changes
  • Posterior dens angulation angle
  • Screw insertion angle