greater petrosal nerve

Preganglionic parasympathetic fibres arise in the superior salivary nucleus of the pontine tegmentum. They join with general somatic sensory and special sensory fibres to form the nervus intermedius. The nervus intermedius exits the cranial cavity at the internal auditory meatus, and joins with the motor root of the facial nerve at the geniculate ganglion. While preganglionic parasympathetic fibres pass through the geniculate ganglion, they neither synapse, nor have their cell bodies located there.{{Citation needed|date=July 2023}}

Preganglionic parasympathetic fibres exit the geniculate ganglion as the greater petrosal nerve.{{Citation needed|date=July 2023}}

The greater petrosal nerve also conveys some special sensory nerve fibres which carry gustatory (taste) sensory information from the palate{{Rp|page=22}} that are relayed to the pterygopalatine ganglion by the lesser palatine nerves and are in turn conveyed to the geniculate ganglion by the greater petrosal nerve to synapse in the ganglion.{{Rp|page=370}}

The greater petrosal nerve enters the petrous part of the temporal bone and travels anteromedially through it at a 45° angle. It emerges into the middle cranial fossa upon the anterosuperior surface of the bone{{Rp|page=498}} through the hiatus for greater petrosal nerve alongside the petrosal branch of the middle meningeal artery.{{Cite book |last1=Moore |first1=Keith L. |title=Clinically Oriented Anatomy |last2=Dalley |first2=Arthur F. |last3=Agur |first3=Anne M. R. |publisher=Wolters Kluwer |year=2018 |isbn=978-1-4963-4721-3 |edition=8th |location=}}{{Rp|page=842}}

In the middle cranial fossa, the nerve is situated between the two layers of the dura mater{{Rp|page=450, 498}} and passes obliquely anterior-ward{{Rp|page=450}} along a groove upon the floor of the fossa{{Rp|page=509}} - the groove for the greater petrosal nerve - that is situated upon the anterosuperior aspect of the petrous part of the temporal bone{{Rp|page=842}} and anteromedial to the arcuate eminence, and adjacent and parallel to the lesser petrosal nerve and its own groove.{{Rp|page=509}} The nerve passes deep to the trigeminal ganglion to reach the foramen lacerum.{{Rp|page=498, 509}}

At the foramen lacerum, it unites with the (sympathetic) deep petrosal nerve, forming the nerve of the pterygoid canal (which continues anterior-ward through the pterygoid canal to reach the pterygopalatine fossa and form the pterygopalatine ganglion).{{Rp|page=498}}

During surgery of the middle cranial fossa, manipulation of the dura mater may damage the greater petrosal nerve,{{Rp|page=450, 498}} causing bleeding{{Rp|page=498}} or swelling at the geniculate ganglion; this can compress the facial nerve and cause facial paralysis.{{Rp|page=450, 498}}

File:Gray789.png|Course and connections of the facial nerve in the temporal bone.

File:Gray841.png|Sympathetic connections of the sphenopalatine and superior cervical ganglia.

File:Head lateral gr petrosal nerve.jpg|Head lateral gr petrosal nerve

File:Autonomic Innervation to the Lacrimal Gland (and other glands of the deep face).svg|Depicts nerve branches that are involved in the autonomic innervation of the lacrimal gland. The terminal parts of the pathway are variable between individuals and differ for the other glands of the deep face.

{{Reflist}}

• {{NormanAnatomy|cranialnerves}} ({{NormanAnatomyFig|VII}})
• [https://web.archive.org/web/20060824034327/http://anatomy.med.umich.edu/nervous_system/ear_ans.html University of Michigan Medical School "Dissector Answers - Ear and Nasal Cavity"]

{{Cranial nerves}}

{{Authority control}}

Category:Facial nerve

Category:Cranial nerves

Category:Otorhinolaryngology