Posterior clinoid processes

{{Move section portions to|Petroclinoid ligament|date=July 2023}}

The petroclinoid ligament is a fold of dura matter. It extends between the posterior clinoid process and anterior clinoid process and the petrosal part of the temporal bone of the skull. There are two separate bands of the ligament; named the anterior and posterior petroclinoid ligaments respectively. The anterior petroclinoid ligament is considered to be an extension of the tentorium cerebelli and the posterior petroclinoid ligament arises from the posteromedial extensions of the tentorial notch. The anterior and posterior petroclinoid ligaments are bands composed of collagen and elastic fibres that are densely packed in fascicles {{Cite journal|last=J. Skrzat, J. Walocha, J.K. Jaworek, I. Mróz|date=23 November 2006|title=The clinical significance of the petroclinoid ligament|journal=Via Medica|volume=66|pages=39–43|s2cid=10568096}}

Their function:

The anterior petroclinoid ligament acts to laterally limit the superior wall of the cavernous sinus. The posterior petroclinoid ligament limits the posterior wall of the cavernous sinus. The angle between the two ligaments varies from 20 to 55 degrees.{{Cite book|title=Skull base and related structure. Atlas of clinical anatomy.|last=Lang|first=Johannes|publisher=Schattauer|year=1995|location=Stuttgart}}{{Cite book|title=Clinically oriented anatomy. 4th Edition.|vauthors=Moore KL, Dalley AF |publisher=Lippincott Williams & Wilkins|year=1999|location=Philadelphia}}

Anatomical Relations and Clinical significance:

The posterior petroclinoid ligament is in close proximity to the oculomotor nerve. During head trauma, it acts as a fulcrum following the downward displacement of the brainstem. This can cause injury to the pupillomotor fibres of the oculomotor nerve, consequently leading to internal ophthalmoplegia{{Cite journal|vauthors=Nagaseki Y, Shimizu T, Kakizawa T, Fukamachi A, Nukui H |date=1989|title=Primary internal ophthalmoplegia due to head injury.|journal=Acta Neurochir (Wien)|volume=97|issue=3–4|pages=117–122|pmid=2718803|doi=10.1007/BF01772821|s2cid=358411}}

The petroclinoid ligament attaches across the notch at the petrosphenoid junction. This forms a foramen, and within this lies the abducens nerve. The abducens nerve travels inferiorly to the petroclinoid ligament {{Cite journal|vauthors=Piffer CR, Zorzetto NL |date=1980|title=Course and relations of the abducens nerve|journal=Anat Anz|volume=147|issue=1|pages=42–46|pmid=7396225}}

Ossification

The petroclinoid ligament could calcify. An ossified form of the ligament may create a syndrome, and this can be seen on a radiograph. The ossified ligament is a typical anatomical anomaly.{{Cite journal|vauthors=Kimonis VE, Mehta SG, Digiovanna JJ, Bale SJ, Pastakia B |date=2004|title=Radiological features in 82 patients with nevoid basal cell carcinoma (NBCC or Gorlin) syndrome.|journal=Genet Med|volume=6|issue=6|pages=495–502|pmid=15545745|doi=10.1097/01.GIM.0000145045.17711.1C|doi-access=free}}{{Cite journal|vauthors=Reddy DR, Prasad VS, Reddy JJ, Prasad BC |date=1993|title=Neuro-radiology of skeletal fluorosis.|journal=Ann Acad Med Singapore|volume=22|issue=3 Suppl|pages=493–500|pmid=8215206}}File:Posterior clinoid process.jpg

Clinoid likely comes from the Greek root klinein or the Latin clinare, both meaning "sloped" as in "inclined."

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• {{cite web|url=http://www.tk.de/rochelexikon/pics/s34257.000-2.html|title=Anatomy diagram: 34257.000-2|work= Roche Lexicon - illustrated navigator|publisher= Elsevier|archive-url=https://web.archive.org/web/20130622050647/http://www.tk.de/rochelexikon/pics/s34257.000-2.html|archive-date=2013-06-22}}
• {{SUNYAnatomyFigs|22|5b|06}}

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Category:Bones of the head and neck

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