Anat Cell Biol.  2016 Jun;49(2):143-150. 10.5115/acb.2016.49.2.143.

Incidence of pterygospinous and pterygoalar bridges in dried skulls of Koreans

  • 1Department of Oral Anatomy, BK21 PLUS Project, School of Dentistry, Pusan National University, Yangsan, Korea.
  • 2Department of Anatomy, Catholic Institute for Applied Anatomy, College of Medicine, The Catholic University of Korea, Seoul, Korea.


Understanding of morphological structures such as the sphenoid spine and pterygoid processes is important during lateral transzygomatic infratemporal fossa approach. In addition, osseous variations such as pterygospinous and pterygoalar bridges are significant in clinical practice because they can produce various neurological disturbances or block the passage of a needle into the trigeminal ganglion through the foramen ovale. Two hundred and eighty-four sides of Korean adult dry skulls were observed to carry out morphometric analysis of the lateral plate of the pterygoid process, to investigate, for the first time among Koreans, the incidence of the pterygospinous and pterygoalar bony bridges, to compare the results with those available for other regional populations, and to discuss their clinical relevance as described on literatures. The mean of maximum widths of the left and right lateral plates of the pterygoid process were 15.99 mm and 16.27 mm, respectively. Also, the mean of maximum heights of the left and right lateral plates were 31.02 mm and 31.01 mm, respectively. The ossified pterygospinous ligament was observed in 51 sides of the skulls (28.0%). Ossification of the pterygospinous ligament was complete in four sides (1.4%). In 47 sides (16.6%), the pterygospinous bridge was incomplete. The ossified pterygoalar ligament was observed in 24 sides of the skulls (8.4%). Ossification was complete in eight sides (2.8%) and incomplete in 16 sides (5.6%). This detailed analysis of the lateral plate of the pterygoid process and related ossification of ligaments can improve the understanding of complex clinical neuralgias associated with this region.


Pterygoid process; Sphenoid spine; Pterygospinous bridge; Pterygoalar bridge

MeSH Terms

Foramen Ovale
Trigeminal Ganglion


  • Fig. 1 Classification of the pterygospinous and pterygoalar bridges including degree of completeness. (A) Incomplete pterygospinous bridging (arrows). (B) Complete pterygospinous bridging. (C) Incomplete pterygoalar bridging. (D) Complete pterygoalar bridging. AT, articular tubercle; FO, foramen ovale; FS, foramen spinosum; LPP, lateral plate of the pterygoid process; MF, mandibular fossa; SP, styloid process.

  • Fig. 2 (A, B) Illustrations showing the morphometric items measured on the lateral plate of the pterygoid process and around structures. Written descriptions of these measurements can be found in Table 1.

  • Fig. 3 Ossified pterygospinous ligament. Incomplete pterygospinous bridges (arrows) (A) and pterygospinous foramina (arrowheads) (B) formed by complete pterygospinous bridges. FO, foramen ovale; FS, foramen spinosum; LPP, lateral plate of the pterygoid process.

  • Fig. 4 Ossified pterygoalar ligament. Incomplete pterygoalar bridge (arrows) (A) and pterygoalar foramen (arrow head) (B) formed by complete pterygoalar bridge. FO, foramen ovale; LPP, lateral plate of the pterygoid process.


1. Standring S, Borley NR, Collins P, Crossman AR, Gatzoulis MA, Healy JC, Johnson D, Mahadevan V, Newell RL, Wigley K. Gray's anatomy: the anatomical basis of clinical practice. 40th ed. London: Churchill Livingstone;2008. p. 415.
2. Donovan MG, Ondra SL, Illig JJ, Dickerson NC. Combined transmandibular-zygomatic approach and infratemporal craniotomy for intracranial skull base tumors. J Oral Maxillofac Surg. 1993; 51:754–758.
3. Mickey B, Close L, Schaefer S, Samson D. A combined frontotemporal and lateral infratemporal fossa approach to the skull base. J Neurosurg. 1988; 68:678–683.
4. Prades JM, Timoshenko A, Merzougui N, Martin C. A cadaveric study of a combined trans-mandibular and trans-zygomatic approach to the infratemporal fossa. Surg Radiol Anat. 2003; 25:180–187.
5. Kapur E, Dilberović F, Redzepagić S, Berhamović E. Variation in the lateral plate of the pterygoid process and the lateral subzygomatic approach to the mandibular nerve. Med Arh. 2000; 54:133–137.
6. Gerber AM. Improved visualization of the foramen ovale for percutaneous approaches to the gasserian ganglion. Technical note. J Neurosurg. 1994; 80:156–159.
7. Gusmao S, Oliveira M, Tazinaffo U, Honey CR. Percutaneous trigeminal nerve radiofrequency rhizotomy guided by computerized tomography fluoroscopy. Technical note. J Neurosurg. 2003; 99:785–786.
8. Peuker ET, Fischer G, Filler TJ. Entrapment of the lingual nerve due to an ossified pterygospinous ligament. Clin Anat. 2001; 14:282–284.
9. Srisopark SS. Ossification of some normal ligaments of the human skull which produce new structures: the pterygospinous and pterygoalar bars and foramina, and the caroticoclinoid foramen. J Dent Assoc Thai. 1974; 24:213–224.
10. Saran RS, Ananthi KS, Subramaniam A, Balaji MT, Vinaitha D, Vaithianathan G. Foramen of civinini: a new anatomical guide for maxillofacial surgeons. J Clin Diagn Res. 2013; 7:1271–1275.
11. Chouke KS. Injection of mandibular nerve and gasserian ganglion: an anatomic study. Am J Surg. 1949; 78:80–85.
12. Patnaik VV, Singla RK, Sanju B. Bilateral pterygo-alar bar and porus crotaphitico buccinatorius: a case report. J Anat Soc India. 2001; 50:161–162.
13. Antonopoulou M, Piagou M, Anagnostopoulou S. An anatomical study of the pterygospinous and pterygoalar bars and foramina: their clinical relevance. J Craniomaxillofac Surg. 2008; 36:104–108.
14. Shaw JP. Pterygospinous and pterygoalar foramina: a role in the etiology of trigeminal neuralgia? Clin Anat. 1993; 6:173–178.
15. Chouke KS, Hodes PJ. The ptergoalar bar and its recognition by roentgen methods in trigeminal neuralgia. Am J Roentgenol Radium Ther. 1951; 65:180–182.
16. Hauser G, De Stefano GF. Epigenetic variants of the human skull. Stuttgart: E. Schweizerbart'sche Verlagsbuchhandlung. 1989. p. 156–161.
17. Peker T, Karaköse M, Anil A, Turgut HB, Gülekon N. The incidence of basal sphenoid bony bridges in dried crania and cadavers: their anthropological and clinical relevance. Eur J Morphol. 2002; 40:171–180.
18. Piagkou MN, Demesticha T, Piagkos G, Androutsos G, Skandalakis P. Mandibular nerve entrapment in the infratemporal fossa. Surg Radiol Anat. 2011; 33:291–299.
19. Krmpotić-Nemanić J, Vinter I, Hat J, Jalsovec D. Mandibular neuralgia due to anatomical variations. Eur Arch Otorhinolaryngol. 1999; 256:205–208.
20. Skrzat J, Walocha J, Srodek R. An anatomical study of the pterygoalar bar and the pterygoalar foramen. Folia Morphol (Warsz). 2005; 64:92–96.
21. Lang J. Skull base and related structures: atlas of clinical anatomy. Stuttgart: Schattauer;1995. p. 55–57.
22. Suazo GI, Zavando MD, Smith RL. Anatomical study of the pterygospinous and pterygoalar bony bridges and foramens in dried crania and its clinical relevance. Int J Morphol. 2010; 28:405–408.
23. Newton TH, Potts DG. Radiology of the skull and brain. St. Louis, MO: Mosby;1971. p. 307.
24. Rouviere H, Delmas A. Descriptive, topographical, and functional human anatomy. Barcelona: Masson;1999.
25. Tebo HG. The pterygospinous bar in panoramic roentgenography. Oral Surg Oral Med Oral Pathol. 1968; 26:654–657.
26. von Ludinghausen M, Kageyama I, Miura M, Alkhatib M. Morphological peculiarities of the deep infratemporal fossa in advanced age. Surg Radiol Anat. 2006; 28:284–292.
27. Lepp FH, Sandner O. Anatomic-radiographic study of ossified pterygospinous and "innominate" ligaments. Oral Surg Oral Med Oral Pathol. 1968; 26:244–260.
28. Pinar Y, Arsu G, Aktan Ikiz ZA, Bilge O. Pterygospinous and pterygoalar bridges. Sendrom. 2004; 16:66–69.
29. Priman J, Etter LE. The pterygospinous and pterygoalar bars. Med Radiogr Photogr. 1959; 35:2–6.
30. Das S, Paul S. Ossified pterygospinous ligament and its clinical implications. Bratisl Lek Listy. 2007; 108:141–143.
31. Nayak SR, Saralaya V, Prabhu LV, Pai MM, Vadgaonkar R, D'Costa S. Pterygospinous bar and foramina in Indian skulls: incidence and phylogenetic significance. Surg Radiol Anat. 2007; 29:5–7.
Full Text Links
  • ACB
export Copy
  • Twitter
  • Facebook
Similar articles
Copyright © 2023 by Korean Association of Medical Journal Editors. All rights reserved.     E-mail: