The pterion–asterion relationship in Anatolian skulls: a morphological and morphometric study

Abstract

Objectives: The pterion and asterion are important cranial landmarks used in anatomical orientation. Although both have been widely studied individually, data on their combined morphology and spatial relationship remain limited. This study aimed to evaluate the morphology and morphometric relationships of the pterion and asterion in adult dry skulls and to compare findings between two anatomical collections. Methods: A total of 38 adult dry human skulls from the anatomical collections of Demokrasi University and Selçuk University were examined. The pterion was classified according to Murphy’s classification, and the asterion based on the presence of a sutural bone. Positional classification of the pterion was performed relative to the zygomatic arch and frontozygomatic suture. Bilateral morphometric measurements were obtained using a digital caliper and analyzed statistically. Results: The sphenoparietal type was the most common pterion configuration. A sutural bone at the asterion was observed in 35.5% of the examined sides. Several morphometric parameters differed significantly between collections. The pterion–zygomatic arch and pterion–frontozygomatic suture distances were greater in Selçuk skulls. High and posterior pterion types were also more frequent in this group. The mean pterion–asterion distance was approximately 89 mm, with no significant side or collection-related difference. Conclusion: The findings demonstrate intercollection differences in the position of the pterion and in several morphometric relationships. These data provide additional morphometric information on their spatial relationship and may provide additional reference data for anatomical studies.

Keywords

• anatomic landmarks
• anatomic variation
• asterion
• cephalometry
• pterion
• skull

References

1. Day JD, Kellogg JX, Tschabitscher M, Fukushima T. Surface and superficial surgical anatomy of the posterolateral cranial base: significance for surgical planning and approach. Neurosurgery 1996;38:1079–84.
2. Tubbs RS, Loukas M, Shoja MM, Bellew MP, Cohen-Gadol AA. Surface landmarks for the junction between the transverse and sigmoid sinuses: application of the “strategic” burr hole for suboccipital craniotomy. Neurosurgery 2009;65(6 Suppl):37–41.
3. Oguz O, Sanli SG, Bozkir MG, Soames RW. The pterion in Turkish male skulls. Surg Radiol Anat 2004;26:220–4.
4. Standring S, editor. Gray’s anatomy: the anatomical basis of clinical practice. 42nd ed. London: Elsevier; 2021.
5. Yasargil MG. Microsurgical pterional approach to the aneurysms of the basilar bifurcation. Surg Neurol 1976;6:83–91.
6. Luzzi S, Giotta Lucifero A, Bruno N, Baldoncini M, Campero A, Galzio R. Pterional approach. Acta Biomed 2021;92(Suppl 4):e2021420.
7. Ukoha U, Oranusi CK, Okafor JI, Udemezue OO, Anyabolu AE, Nwamarachi TC. Anatomic study of the pterion in Nigerian dry human skulls. Niger J Clin Pract 2013;16:325–8.
8. Dutt V, Shankar VV, Shetty S. Morphometric study of pterion and asterion in adult human skulls of Indian origin. International Journal of Anatomy and Research 2017;5:3837–42.

9. Triantafyllou G, Karangeli N, Duparc F, Piagkou M, Galzio R, Tsakotos G, Botis G, Kalamatianos T, Luzzi S. Unveiling pterion variability: a meta-analytic approach to enhance neurosurgical precision. Surg Radiol Anat 2025;47:66.
10. Amini A, Swiatek VM, Stein KP, Rashidi A, Sandalcioglu IE, Neyazi B. Pterional vs. lateral supraorbital approach in the management of middle cerebral artery aneurysms: insights from a phantom model study. Neurosurg Rev 2024;47:344.
11. Ersoy M, Evliyaoglu C, Bozkurt MC, Konuskan B, Tekdemir I, Keskil IS. Epipteric bones in the pterion may be a surgical pitfall. Minim Invasive Neurosurg 2003;46:363–5.
12. Cowan PT, Sandhu G, Adigun OO. Anatomy, head and neck: asterion. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023.
13. Saygın DA, Aydin Kabakci AD, Alpa S, Buyukmumcu M, Yilmaz MT. Typing and morphometric analysis of the pterion on human skull of central Anatolia. Journal of Anatomical Society of India 2022;71:61–70.
14. Aksu F, Akyer SP, Kale A, Geylan S, Gayretli O. The localization and morphology of pterion in adult West Anatolian skulls. J Craniofac Surg 2014;25:1488–91.
15. Ucerler H, Govsa F. Asterion as a surgical landmark for lateral cranial base approaches. J Craniomaxillofac Surg 2006;34:415–20.
16. Coşkun O, Yiğit M, Çelikgün B, Ok F, Ertaş A, Gayretli O. The morphological and morphometric examination of the asterion in terms of surgical approaches to the posterior cranial fossa. European Journal of Therapeutics 2025;31:90–101.
17. Yadav SK, Shrestha A, Pandey N, Yadav BP, Yadav P, Sharma A, Yadav S, Yadav U. Study of the variations of asterion, pterion and inion in human dry skulls and its anthropological importance. Janaki Medical College Journal of Medical Science 2022;10:23–7.
18. Priya A, Jain A. Morphological and morphometric study of pterion in adult dry human skulls. Academia Anatomica International 2020;6:63–8.
19. Murphy T. The pterion in the Australian aborigine. Am J Phys Anthropol 1956;14:225–44.
20. Kalthur SG, Vangara SV, Kiruba L, Dsouza AS, Gupta C. Metrical and non-metrical study of the pterion in South Indian adult dry skulls with notes on its clinical importance. Marmara Medical Journal 2017;30:30–9.
21. Candy NG, Van Der Veken J, Van Velthoven V. ‘What’s in a name’, a systematic review of the pterional craniotomy for aneurysm surgery and its many modifications with a proposal for simplified nomenclature. Acta Neurochir (Wien) 2024;166:11.
22. Sindel A, Ögüt E, Aytaç G, Oguz N, Sindel M. Morphometric study of pterion. International Journal of Anatomy and Research 2016;4:1954–7.
23. Vasudha TK, D’Sa DS, Gowd S. Study of morphology of pterion and its clinical implications. International Journal of Anatomy and Research 2017;5:4674–8.
24. Lucena JD, Sanders JVS, Brito HM, Collyer MC, Santos Cerqueira G, Diniz de Magalhães DD, de Sá Braga Oliveira A. Morphometric study of the pterion in dry human skulls in Northeastern Brazil. Journal of Morphological Sciences 2020;37:57–63.
25. Uabundit N, Chaiyamoon A, Iamsaard S, Yurasakpong L, Nantasenamat C, Suwannakhan A, Phunchago N. Classification and morphometric features of pterion in Thai population with potential sex prediction. Medicina (Kaunas) 2021;57:1282.
26. Khan Y, Ishwarkumar S, Pillay P. Morphology and morphometry of the asterion in the South African sample within KwaZulu-Natal. Translational Research in Anatomy 2023;32:100258.
27. Kumar TMV, Kumar V, Yadav N. The occurrence of wormian bones within the cranial sutures and their clinical significance. International Journal of Anatomy and Research 2016;4:3082–6.
28. Toro-Ibacache V, Muñoz VZ, O’Higgins P. The relationship between skull morphology, masticatory muscle force and cranial skeletal deformation during biting. Ann Anat 2016;203:59–68.
29. Liang C, Landi F, Çetin IE, Profico A, Buzi C, Dutel H, Khonsari RH, O’Higgins P, Moazen M. Functional adaptation of the infant craniofacial system to mechanical loadings arising from masticatory forces. Proc Biol Sci 2024;291:20240654.
30. Uz A, Ugur HC, Tekdemir I. Is the asterion a reliable landmark for the lateral approach to posterior fossa? J Clin Neurosci 2001;8:146–7.
31. Day JD, Tschabitscher M. Anatomic position of the asterion. Neurosurgery 1998;42:198–9.
32. Mwachaka PM, Hassanali J, Odula PO. Anatomic position of the asterion in Kenyans for posterolateral surgical approaches to cranial cavity. Clin Anat 2010;23:30–3.
33. Li J, Yang H, Ma L, Li Y. Morphological types and localization patterns of pterion in the skulls of adults from southeastern China. Surg Radiol Anat 2022;44:913–24.
34. Aggarwal N, Kaur N, Patra A, Gupta M. Analysis of the variations in the morphology, topography of the pterion, and their implications in neurosurgery: an osteometric study. Asian J Neurosurg 2023;18:581–6.
35. Ari I, Kafa IM, Bakirci S. A comparative study of variation of the pterion of human skulls from 13th and 20th century Anatolia. International Journal of Morphology 2009;27:1291–8.