Pterygoid bone

Skull diagram with 26 colors labeling individual single or paired bones
Skull diagram of Champsosaurus, showing the pterygoid bone in red-violet (visible in inferior view at lower right and posterior to the ectopterygoid bone in lateral view at top)
Skull of the early reptile Milleretta (Millerettidae), showing the pterygoid bearing palatal teeth in green (labeled pt, bottom right)

The pterygoid is a paired bone forming part of the palate of many vertebrates, behind the palatine bones. In fishes, it is often known as the entopterygoid or mesopterygoid, to distinguish it from the ectopterygoid.

Anatomy

The pterygoid is a flat and thin lamina, united to the underside of the sphenoid region. Anteriorly, it typically contacts the vomer; laterally, it contacts the palatine and ectopterygoid; posteriorly it contacts the quadrate. Posterolaterally it forms the border of the subtemporal fenestra. In many early tetrapods the pterygoid bears teeth (palatal dentition), which are retained by some living squamates.

The pterygoid ossifies intramembranously.

Evolution

The entopterygoid is present in teleosts, but its homology is unclear.

In mammals, the pterygoid fuses with the ectopterygoid; the resulting fusion is sometimes referred to simply as the pterygoid.

In humans, the pterygoid-ectopterygoid element fuses with the orbitosphenoids, the alisphenoid, the presphenoid, and the basisphenoid to become to the sphenoid bone, of which it is the pterygoid process.

References

  1. ↑ "Origin of the pterygoid bone and pharyngeal musculature in mammals". crompton.oeb.harvard.edu. Retrieved 2024-01-29.
  2. ↑ Jollie, Malcolm (1986). "A primer of bone names for the understanding of the actinopterygian head and pectoral girdle skeletons". Canadian Journal of Zoology. 64 (2). NRC Research Press: 365–379. doi:10.1139/z86-058. ISSN 0008-4301.
  3. ↑ Kardong, Kenneth (2015). Vertebrates: Comparative Anatomy, Function (7th ed.). McGraw-Hill.
  4. ↑ Matsumoto, Ryoko; Evans, Susan E. (January 2017). "The palatal dentition of tetrapods and its functional significance". Journal of Anatomy. 230 (1): 47–65. doi:10.1111/joa.12534. ISSN 0021-8782. PMC 5192890. PMID 27542892.
  5. 1 2 Mead, James G.; Fordyce, R. Ewan (2009). "The therian skull : a lexicon with emphasis on the odontocetes". Smithsonian Contributions to Zoology. Smithsonian Institution Scholarly Press.
  6. ↑ Gardiner, B. G.; Gardiner, B. G. (1984). "The relationships of the palaeoniscid fishes, a review based on new specimens of Mimia and Moythomasia from the Upper Devonian of Western Australia". Bulletin of the British Museum (Natural History) Geology. 37: 173––428.
  7. ↑ Presley, R.; Steel, F. L. D. (1978-01-01). "The pterygoid and ectopterygoid in mammals". Anatomy and Embryology. 154 (1): 95–110. doi:10.1007/BF00317957. ISSN 1432-0568.
  8. ↑ Hirano-Kawamoto, Ai; Yamamoto, Masahito; Honkura, Yohei; Murakami, Gen; Hayashi, Shogo; Katori, Yukio (2026-06-30). "Distinct delayed development of the basisphenoid–ethmoid interface in human fetuses: a histological study using human fetuses". Anatomy & Cell Biology. 59 (2). Korean Association of Anatomists: 318–328. doi:10.5115/acb.25.299. PMC 13291705. PMID 42056064.

Baumel, J. J. (1993). "4. Osteologia". Handbook of Avian Anatomy: Nomina Anatomica Avium. Publications of the Nuttall Ornithological Club. Vol. 23 (2 ed.). Cambridge, Massachusetts: Nuttall Ornithological Club. LCCN 94102039. OCLC 29278198.