The parasympathetic preganglionic fibers stems from facial nerve in medulla which traverses as a greater petrosal nerve
. Post ganglionic parasympathetic fibers innervate lacrimal, salivary and nasal glands.
The incus and the malleus' head were removed to provide access to the SGF, which is the triangular anatomical area between the FN (tympanic portion), the GG and the greater petrosal nerve
caudally, the MCF dura cranially, and the labyrinthine bloc dorsally (Figure 2) [4-7].
It then gives branches over the preauricular and temporal areas. The parasympathetic chain to parotid consists of the preganglionic fibers that originate in the inferior salivatory nucleus and travels with the glossopharyngeal nerve, tympanic nerve, and lesser petrosal nerve
to the otic ganglion.
When present the foramen petrosum transmits the lesser petrosal nerve
. When not present the nerve exits via foramen ovale (Feneis & Dauber, 2000).
It connects infratemporal fossa to the middle cranial fossa and transmits the mandibular nerve, accessory meningeal artery and lesser petrosal nerve
and emissary vein which connects the cavernous venous sinus to the pterygoid venous plexus in the infratemporal fossa.
Sensory information from the skin of the external auditory canal, concha, and from the mucous membranes of the nasopharynx and palate is carried via the greater petrosal nerve
that originates from the geniculate ganglion.
The first branch of the facial nerve, the greater superficial petrosal nerve
(GSPN), exits anteriorly from the geniculate ganglion.
(1) Meningiomas can be confined to the IAC because the arachnoid villi can be distributed within the IAC and along the superficial petrosal nerve
. (2) Vestibular schwannomas are isohyperintense, but meningiomas have variable signal intensity on T2-weighted MR images.
The parasympathetic division of cranial nerve VII supplies fibers that contribute to the greater petrosal nerve
(which supplies the lacrimal gland), the lesser petrosal nerve
(which supplies the parotid gland), and the chorda tympani (which supplies the submandibular and sublingual glands).
This nerve's sympathetic component (deep petrosal nerve
) comes from the common carotid plexus and the superior cervical sympathetic ganglion.
It is surrounded by various clinically significant structures, including the cochlea, middle ear, eustachian tube, gasserian ganglion, geniculate ganglion, greater superficial petrosal nerve
, and jugular fossa.
Functional components of the greater superficial petrosal nerve