Surgical and Radiologic Anatomy

, Volume 41, Issue 9, pp 985–1001 | Cite as

Atlas posterior arch and vertebral artery’s groove variants: a classification, morphometric study, clinical and surgical implications

  • Konstantinos NatsisEmail author
  • Evangelia-Theophano Piperaki
  • Moschos Fratzoglou
  • Nikolaos Lazaridis
  • Parmenion P. Tsitsopoulos
  • Αlexandros Samolis
  • Michael Kostares
  • Maria Piagkou
Original Article



The third part of the vertebral artery (VA) coursing in vertebral artery groove (VAG) may be injured during posterior craniocervical junction approaches.


The current study classifies all possible variants of the posterior arch (PA) of the atlas vertebra (C1), focusing on VAG and calculates their incidence. PA and VAG morphometry is studied in correlation with gender and age. Clinical and surgical implications of recorded variants are provided in an effort to explain associated pathology. The usefulness of three-dimensional computed tomography (3D-CT) in detecting PA variants is highlighted.

Materials and methods

Two hundred and forty-four Greek adult dry C1 were classified in types according to PA morphology [i.e. presence of an imprint or a distinct VAG and occurrence of a partially or completely ossified dorsal (PDP or CDP) or lateral (PLP or CLP) ponticle unilaterally or bilaterally]. Combined variants were also included.


A VAG and an imprint were detected in 42.62% and 15.16%. A PDP and CDP were observed in 18.03% and 15.98%, while a CLP and PLP in 2.05% and 1.64%, respectively. Combined PDP and PLP were detected in 2.05%, a CDP and CLP similarly to a CDP and PLP in 1.23% and a PDP and CLP in 0.40%.


Variants’ classification will contribute to an in depth understanding of the complex C1 anatomy and may explain cases of VA entrapment and injury during PA fixation. Surgeons should carefully study 3D-CT imaging to ensure type, location, size and shape of C1 ponticles in combination with VAG morphology and VA course before screw insertion.


Atlas vertebra Posterior arch Posterior ponticle Lateral ponticle Vertebral artery groove Variation Ossification 



Atlas vertebra


Posterior arch


Vertebral artery


Vertebral artery groove




Dorsal ponticle


Lateral ponticle


Partially ossified dorsal ponticle


Completely ossified dorsal ponticle


Partially ossified lateral ponticle


Completely ossified lateral ponticle


Dorsolateral ponticle


Lateral mass


Transverse process


Transverse foramen


Arcuate foramen


Retrotransverse foramen


Right side


Left side


Linear distance of vertebral artery groove from the posterior midline to the most medial edge of vertebral artery groove on the inner cortex


Linear distance of vertebral artery groove from the posterior midline to the most medial edge of vertebral artery groove on the outer cortex


Linear distances of vertebral artery groove from the posterior midline to the most lateral edge of vertebral artery groove to the inner cortex


Linear distances of vertebral artery groove from the posterior midline to the most lateral edge of vertebral artery groove to the outer cortex


Technical error of measurement


Relative technical error of measurement


Coefficient of reliability


Author contributions

KN: project development, data analysis, classification system, manuscript editing and final approval, ETP: data collection, data analysis, schematic drawings, PPT, MF and NL: manuscript editing, AS: data analysis, manuscript editing, MK: data analysis, and MP: project development, data collection, data analysis and manuscript editing.

Compliance with ethical standards

Conflict of interest

There is no conflict of interest.

Informed consent

The authors of the current study express their gratitude to the body donors who donated their bodies before death (written informed consent) and throughout this act; their vertebrae were used for this study.


  1. 1.
    Ansari MS, Singla M, Ravi KS, Goel P (2015) Morphometric analysis of atlas and its clinical significance: an anatomical study of indian human atlas vertebrae. Indian J Neurosurg 4:92–97CrossRefGoogle Scholar
  2. 2.
    Arslan D, Ozer MA, Govsa F, Kıtıs O (2018) The ponticulus posticus as risk factor for screw insertion into the first cervical lateral mass. World Neurosurg 113:579–585. (Epub 2018 Feb 25) CrossRefGoogle Scholar
  3. 3.
    Barge JAJ (1918) Problems in kranio-vertebral Gebiet section. Verh K Akad Wetensch Amsterdam 20(2):102–105Google Scholar
  4. 4.
    Bodon G, Grimm A, Hirt B, Seifarth H (2016) Applied anatomy of screw placement via the posterior arch of the atlas and anatomy-based refinements of the technique. Eur J Orthop Surg Traumatol 26:793–803CrossRefGoogle Scholar
  5. 5.
    Chevrel JP, Pineau H, Delmas A (1965) L’arc postérieur de l’atlas, ses variations, étude morphologique et statistique. CR Assoc Anat 50:280–288Google Scholar
  6. 6.
    Christensen DM, Eastlack RK, Lynch JJ, Yaszemski MJ, Currier BL (2007) C1 anatomy and dimensions relative to lateral mass screw placement. Spine 32:844–848CrossRefGoogle Scholar
  7. 7.
    Cirpan S, Yonguc GN, Edizer M, Mas NG, Magden AO (2017) Foramen arcuale: a rare morphological variation located in atlas vertebrae. Surgi Radiol Anat 39(8):877–884CrossRefGoogle Scholar
  8. 8.
    Srijit Das, Suri R, Kapur V (2005) Double foramen transversarium. An osteological study with clinical implications. Int Med J 12:311–313Google Scholar
  9. 9.
    De Carvalho MF, Rocha RT, Monteiro JTS, Pereira CU, Leite RF, Defino HLA (2009) Vertebral artery groove anatomy. Acta Ortop Bras 17:50–54CrossRefGoogle Scholar
  10. 10.
    Dhall U, Chhabra S, Dhall JC (1993) Bilateral asymmetry in bridges and superior articular facets of atlas vertebra. J Anat Soc India 42:23–27Google Scholar
  11. 11.
    Ebraheim NA, Xu R, Lin D, Ahmad M, Heck BE (1998) The quantitative anatomy of the vertebral artery groove of atlas and its relation to the posterior atlanto-axial approach. Spine 23:320–323CrossRefGoogle Scholar
  12. 12.
    El-S Hassanein GH (2013) Injury risk of vertebral artery during screw placement through atlas posterior arch. Basic Sci Med 2:21–23Google Scholar
  13. 13.
    Gosavi SN, Vatsalaswamy P (2012) Morphometric study of the atlas vertebra using manual method. Malays Orthop J 6:18–20CrossRefGoogle Scholar
  14. 14.
    Gupta C, Radhakrishnan P, Palimar V, D’Souza AS, Kiruba NL (2013) A quantitative analysis of atlas vertebrae and its abnormalities. J Morphol Sci 30(Suppl 2):77–81Google Scholar
  15. 15.
    Gupta T (2008) Quantitative anatomy of vertebral artery groove on the posterior arch of atlas in relation to spinal surgical procedures. Surg Radiol Anat 30:239–242CrossRefGoogle Scholar
  16. 16.
    Hasan M, Shukla S, Siddiqui MS, Singh D (2001) Posterolateral tunnels and ponticuli in human atlas vertebrae. J Anat 199:339–343CrossRefGoogle Scholar
  17. 17.
    Huang DG, He SM, Pan JW, Hui H, Hu HM, He BR, Li H, Zhang XF, Hao DJ (2014) Is the 4 mm height of the vertebral artery groove really a limitation of C1 pedicle screw insertion? Eur Spine J 23:1109–1114CrossRefGoogle Scholar
  18. 18.
    Ishak B, Schneider T, Tubbs RS, Gimmy V, Younsi A, Unterberg AW, Kiening KL (2017) Modified posterior C1 lateral mass screw insertion for type II odontoid process fractures using intraoperative computed tomography-based spinal navigation to minimize postoperative occipital neuralgia. World Neurosurg 107:194–201CrossRefGoogle Scholar
  19. 19.
    Karau PB, Ogeng’o JA, Hassanali J, Odula P (2010) Anatomy and prevalence of atlas vertebrae bridges in a Kenyan population: an osteological study. Clin Anat 23:649–653CrossRefGoogle Scholar
  20. 20.
    Khanfour AA, El Sekily NM (2015) Relation of the vertebral artery segment from C1 to C2 vertebrae: an anatomical study. Alexandria J Med 51:143–151CrossRefGoogle Scholar
  21. 21.
    Koutsouraki E, Avdelidi E, Michmizos D, Kapsali SE, Costa V, Baloyannis S (2010) Kimmerle’s anomaly as a possible causative factor of chronic tension-type headaches and neurosensory hearing loss: case report and literature review. Int J Neurosci 120:236–239CrossRefGoogle Scholar
  22. 22.
    Le Double AF (1912) Traité des variations de la colonne vertébrale de l’homme. Vigot, ParisGoogle Scholar
  23. 23.
    Le Minor JM (1997) The retrotransverse foramen of the human atlas vertebra: a distinctive variant within primates. Acta Anat (Basel) 160(3):208–212CrossRefGoogle Scholar
  24. 24.
    Ma X-Y, Yin Q-S, Wu Z-H, Xia H, Lu J-F, Zhong S-Z (2005) Anatomic considerations for the pedicle screw placement in the first cervical vertebra. Spine 30:1519–1523CrossRefGoogle Scholar
  25. 25.
    Macalister A (1869) Notes on the homologies and comparative anatomy of the atlas and axis. J Anat 3:54–64Google Scholar
  26. 26.
    Ouyang ZY, Qiu MJ, Zhao Z, Wu XB, Tong LS (2017) Congenital anomaly of the posterior arch of the atlas: a rare risk factor for posterior circulation stroke. J Neurointerventional Surg 9(7):e27CrossRefGoogle Scholar
  27. 27.
    Patel NP, Gupta DS (2016) A morphometric study of adult human atlas vertebrae in South Gujarat population, India. Int J Res Med Sci 4:4380–4386CrossRefGoogle Scholar
  28. 28.
    Pękala PA, Henry BM, Pękala JR, Hsieh WC, Vikse J, Sanna B, Walocha JA, Tubbs RS, Tomaszewski KA (2017) Prevalence of foramen arcuale and its clinical significance: a meta-analysis of 55,985 subjects. J Neurosurg Spine 27:276–290CrossRefGoogle Scholar
  29. 29.
    Pękala PA, Henry BM, Phan K, Pękala JR, Taterra D, Walocha JA, Tubbs RS, Tomaszewski KA (2018) Presence of a foramen arcuale as a possible cause for headaches and migraine: systematic review and meta-analysis. J Clin Neurosci 54:113–118CrossRefGoogle Scholar
  30. 30.
    Radojevic S, Negovanovic B (1963) La gouttière et les anneaux osseux de l’artère vertébrale de l’atlas. Acta Anat (Basel) 55:186–194CrossRefGoogle Scholar
  31. 31.
    Ravichandan ND, Shanthi KC, Shrinivasan V (2011) Vertebral artery groove in the atlas and its clinical significance. J Clin Diagnos Res 5:542–545Google Scholar
  32. 32.
    Rekha BS, D’Sa Divya Shanthi (2016) Morphometric anatomy of the atlas (C1) vertebra among Karnataka population in India. Int J Anat Res 4:1981–1984CrossRefGoogle Scholar
  33. 33.
    Sanchis-Gimeno JA, Llido S, Perez-Bermejo M, Nalla S (2018) Prevalence of anatomic variations of the atlas vertebra. Spine J. 2018Google Scholar
  34. 34.
    Sato E, Noriyasu S (1978) Studies on the ponticulus posterior and ponticulus lateralis of the human first cervical vertebra. Sapporo Med J 47:599–617Google Scholar
  35. 35.
    Saunders SR, Popovich S (1978) A family study of two skeletal variants: atlas bridging and clinoid bridging. Am J Phys Anthropol 49:193–204CrossRefGoogle Scholar
  36. 36.
    Sengul G, Kadioglu HH (2006) Morphometric anatomy of atlas and axis vertebra. Turkish Neurosurgery 16:69–76Google Scholar
  37. 37.
    Senoglu M, Gümüşalan Y, Yüksel KZ, Uzel M, Celik M, Ozbag D (2006) The effect of posterior bridging of C-1 on craniovertebral junction surgery. J Neurosurg Spine 5:50–52CrossRefGoogle Scholar
  38. 38.
    Smith JD, Jack MM, Harn NR, Bertsch JR, Arnold PM (2016) Screw placement accuracy and outcomes following O-Arm-navigated atlantoaxial fusion: a feasibility study. Global Spine J 6:344–349CrossRefGoogle Scholar
  39. 39.
    Song MS, Lee HJ, Kim JT, Kim JH, Hong JT (2017) Ponticulus posticus: morphometric analysis and Its anatomical Implications for occipito-cervical fusion. Clin Neurol Neurosurg 157:76–81CrossRefGoogle Scholar
  40. 40.
    Tan M, Wang H, Wang W, Zhang G, Yi P, Li Z, Wei H, Yang F (2003) Morphometric evaluation of screw fixation in atlas via posterior arch and lateral mass. Spine 28:888–895Google Scholar
  41. 41.
    Vaněk P, Bradáč O, de Lacy P, Konopková R, Lacman J, Beneš V (2017) Vertebral artery and osseous anomalies characteristic at the craniocervical junction diagnosed by CT and 3D CT angiography in normal Czech population: analysis of 511 consecutive patients. Neurosurg Rev 40:369–376CrossRefGoogle Scholar
  42. 42.
    Von Torklus D, Gele W (1972) The upper cervical spine. Grune and Stratton, New York, pp 28–30Google Scholar
  43. 43.
    Wright NM, Lauryssen C (1998) Vertebral artery injury in C1–C2 transarticular screw fixation: results of a surgery of the AANS/CNS section on disorders of the spine and peripheral nerves. J Neurosurg 88:634–640CrossRefGoogle Scholar
  44. 44.
    Yamaguchi S, Eguchi K, Kiura Y, Takeda M, Kurisu K (2008) Posterolateral protrusion of the vertebral artery over the posterior arch of the atlas: quantitative anatomical study using three-dimensional computed tomography angiography. J Neurosurg Spine 9:167–174CrossRefGoogle Scholar
  45. 45.
    Yeom JS, Kafle D, Nguyen NQ, Noh W, Park KW, Chang BS, Lee CK, Riew KD (2012) Routine insertion of the lateral mass screw via the posterior arch for C1 fixation: feasibility and related complications. Spine J 12:476–483CrossRefGoogle Scholar

Copyright information

© Springer-Verlag France SAS, part of Springer Nature 2019

Authors and Affiliations

  • Konstantinos Natsis
    • 1
    Email author
  • Evangelia-Theophano Piperaki
    • 2
  • Moschos Fratzoglou
    • 3
  • Nikolaos Lazaridis
    • 1
  • Parmenion P. Tsitsopoulos
    • 4
  • Αlexandros Samolis
    • 5
  • Michael Kostares
    • 5
  • Maria Piagkou
    • 5
  1. 1.Department of Anatomy and Surgical Anatomy, Faculty of Health Sciences, School of MedicineAristotle University of ThessalonikiThessalonikiGreece
  2. 2.Department of Microbiology, School of MedicineNational and Kapodistrian University of AthensAthensGreece
  3. 3.Department of NeurosurgeryGeneral District Hospital of NikaiaPiraeusGreece
  4. 4.Department of Neurosurgery, Hippokratio General Hospital, School of MedicineAristotle University of ThessalonikiThessalonikiGreece
  5. 5.Department of Anatomy, Faculty of Health Sciences, School of MedicineNational and Kapodistrian University of AthensAthensGreece

Personalised recommendations