Microganglia

In addition to microganglia in the nerve of the pterygoid canal and also near outstanding glands, microganglia take place in several various other branches of the facial and also glossopharyngeal nerves (Figure 5.1).

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A prominent group of microganglia wake up in the cavernous plexus, lied intracranially but extradurally. The biggest ganglion, containing around 500 neurons, sits between the internal carotid plexus and also the abducens nerve (6n; Gellert, 1934; Ruskell and also Simons, 1987). In the same region are number of smaller ganglia (Mitchell, 1953c), while one more collection lies in between the abducens nerve and also the ophthalmic nerve (Gellert, 1934). Much more rostrally, these microganglia and also their interconnections kind the retroorbital plexus (Ruskell, 1970a; Ruskell and also Simons, 1987), i m sorry communicates directly with the pterygopalatine ganglion via the orbital rami (Ruskell, 1970a).

The facial nerve communicates with the cavernous plexus via the better superficial petrosal nerve (Chorobski and also Penfield, 1932). The glossopharyngeal nerve communicates through the cavernous plexus via the lesser petrosal nerve and tiny filaments indigenous the tympanic plexus situated in the middle ear (Rosen, 1950; Mitchell, 1954; Chu, 1968). Teams of ganglion cells happen along every these pathways (Chorobski and also Penfield, 1932; valve Buskirk, 1945; Gibbins et al., 1984) and also probably contribute to cerebral vasodilation (Walters et al., 1986).

Another significant aggregation that ganglion cell lies along the lingual nerve. The anterior two-thirds of the tongue has up come 1500 microganglia (Gomez, 1961; Chu, 1968; Fitzgerald and also Alexander, 1969). They get preganglionic input native both the glossopharyngeal nerve (Gomez, 1961; Fitzgerald and Alexander, 1969) and the face nerve, via the chorda tympani (Hellekant, 1972). These neurons wake up vasodilation and also mucous secretion from the lingual glands (Hellekant, 1972), probably mediated by VIP and also NO (Lundberg et al., 1984).


Jeffrey D. Petersohn MD, in Pain measures in Clinical exercise (Third Edition), 2011

Anatomy

The sphenopalatine (pterygopalatine) ganglion resides in the pterygopalatine fossa, located posterior to the middle nasal concha and also anterior come the pterygoid canal. That is adjacent to and inferior to the maxillary nerve, a branch of the trigeminal nerve, and also connects v it via the pterygopalatine nerves. Just parasympathetic fibers developing in the facial nerve synapse in the ganglion via yarn of the nerve the the pterygoid canal and the better petrosal nerve. Postganglionic fibers continue to the lacrimal, palatine, and also nasal glands via orbital branches of the maxillary, lacrimal, and zygomatic nerves. Postganglionic sympathetic yarn originating in the internal carotid plexus pass with the ganglion (without synapsing) via the nerve the the pterygoid canal and also the deep petrosal nerve. Sensory fibers connect the maxillary nerve come the ganglion by means of branches the the ganglion (primarily maxillary nerve fibers) that extend from the nasopharynx, nasal cavity, palate, and orbit. 5 branches space usually described: The pharyngeal branch provides the sphenoid sinus and the mucosa of the roof the the pharynx, the greater palatine nerve provides posterior inferior sleep branches that supply the palate via the higher palatine foramen (with materials of the maxillary and facial nerves). The tonsil and soft palate are supplied via the lesser palatine nerve together it occurs from the lesser palatine foramen. The nasopalatine nerve emerges through the sphenopalatine foramen, passes follow me the nasal septum, and emerges through the typical incisive foramen to reach the difficult palate. Posterior ethmoid and also sphenoid sinuses listed below the periosteum that the orbit are provided via orbital branches. The nasal cavity is offered via the posterior premium nasal branches.

In enhancement to sensory fibers, the nasopalatine, palatine, and nasal nerves contain vasomotor fibers and secretory fibers to the palatine and also nasal glands. Also, fibers related to taste can be found in the palatine nerves that pass via the greater petrosal nerve to with the facial nerve.38


E.E. Benarroch, in Encyclopedia that the Neurological scientific researches (Second Edition), 2014

Pterygopalatine (Sphenopalatine) Ganglion

The pterygopalatine (or sphenopalatine) ganglion receive preganglionic axons from the face nerve via the better superficial petrosal nerve and also the nerve of the pterygoid canal (Vidian nerve). The pterygopalatine ganglion neurons innervate the lacrimal glands, the blood vessels of the eye, the blood vessels and secretory glands that the nasal cavity and also palate, and also the cerebral blood vessels. Many pterygopalatine ganglion neurons room cholinergic and stimulate secretion of lacrimal, nasal, and palatine glands; VIP and NO are mainly responsible for vasodilation the eye, nasopharynx, and also cerebral vessels.


William DeMyer, in stroke in Children and also Young adults (Second Edition), 2009

Course of internal Carotid Arteries

After developing from the brachiocephalic and subclavian arteries, the usual carotid artery and also ICAs food rostrally through the neck. The ICAs enter the carotid canal in the petrous bone at the basic of the skull, just anterior to the jugular foramen. They leave from the carotid canal with the foramen lacerum, traverse the cavernous sinus, pierce the dura, and also enter the subarachnoid space lateral to the sella turcica. Every ICA to produce extradural, interdural, and intradural branches.

Extradural Branches

Extradural branches that the ICA to happen in the carotid canal before the ICA beginning the cavernous sinus:

Caroticotympanic artery to the tympanic membrane

Pterygoid artery to the pterygoid canal, in firm with the vidian (pterygopalatine = sphenopalatine) nerve


Because the cavernous sinus is a cleft in between two dural layers, the next arteries arise interdurally (inter = existing within or between) (Fig. 2-10).10 Cavernous branches that the ICA prolong to the bordering dura, and also cranial nerves (CNs) III, IV, V, and VI, every one of which run along the cavernous sinus. Branches anastomose with the center meningeal arteries, v the meningeal rami of the ophthalmic arteries (OphtAs), and openly v each other across the midline. The branches and also distribution the the meningohypophyseal tribe (see Fig. 2-10) space as follows:

Inferior hypophyseal artery sends branches to the neurohypophysis

Dorsal meningeal artery (also provides CN through as the runs v Dorello canal in ~ the guideline of the petrous bone)

Tentorial artery (also sends minute branches come CNs III and also IV)

Inferior cavernous sinus artery sends out branches to CNs III, IV, and also VI; the trigeminal ganglion; and also branches the anastomose v the center meningeal arteries


Segments the the ICA are concerned its siphon. To facilitate description on frontal and also lateral angiograms, Fischer-Brügge11 numbered the cavernous an ar of the ICA, MCA, and ACA (Fig. 2-11).

Intradural Branches

The ICA pierces the dural wall of the cavernous sinus to get in the subarachnoid an are just lateral to the optic chiasm currently intradural, the ICA originates in sequence:

OphtA (see Fig. 2-10)—runs forward v the optic foramen come the retina, accompanied by the optic nerve and also ophthalmic vein

Superior hypophyseal artery—supplies the portal device through i m sorry blood-borne messengers indigenous the hypothalamus regulate the relax of adenohypophysial hormones

PcomA (see Fig. 2-4)

AchorA (see Fig. 2-4)


The ICA terminates by bifurcating into the ACA and MCA in the vallecula, which is the beginning of the sylvian fissure. The vallecula is a cistern in the subarachnoid space. The vallecula is roofed by the anterior perforated substance and also bounded medially by the optic chiasm and posterolaterally through the uncus (Fig. 2-12; watch Figs. 2-4 and also 2-22). The first numerical segment of the ICA, MCA, and ACA—C1, M1, and also A1—begin at the vallecula (see Fig. 2-12).


The branches that the face nerve have the right to be separated into intratemporal and also extratemporal branches. The intratemporal branches the the facial nerve room as follows:

Greater petrosal nerve

This branch arises from the geniculate ganglion and is join by the nerve the the pterygoid canal. It includes secretomotor fibers for the lacrimal and also nasal glands.

Nerve come stapedius

Supplies the stapedius muscle, i beg your pardon is responsible for “dampening down” according to noises protecting the middle and inner ear structures

Chorda tympani nerve

This nerve join the lingual nerve (of the mandibular department of the trigeminal nerve—see chapter on trigeminal nerve) and also is distributed to the anterior two-third of the tongue. It contains the following:a.Taste and also sensation yarn from the former two-third the the tongue and also the soft palate.

b.

Preganglionic secretory and also vasodilator fibers that synapse in the submandibular ganglion.


Erin P. Fillmore, note F. Seifert, in Nerves and Nerve Injuries, 2015

Pterygopalatine Ganglion

The PPG is the largest of the peripheral parasympathetic ganglia. It is formed by the cabinet bodies of postganglionic parasympathetic neurons and resides in the PPF just below the maxillary nerve to which that connects by brief ganglionic branches. It is situated anterior come the pterygoid canal and also lateral come the sphenopalatine foramen. This is crucial ganglion the receives three roots: sensory, parasympathetic, and sympathetic. The sensory root is obtained from the maxillary nerve and also conveys the majority of sensory yarn of this nerve via the ganglionic branches (Standring, 2008). These sensory nerves pass v the ganglion without synapsing and also are spread in the nerves leaving the ganglion. The parasympathetic root is obtained from the greater petrosal nerve via the pterygoid canal and also consists the preganglionic parasympathetic yarn from the face nerve, i beg your pardon synapse in ~ the ganglion. Postganglionic parasympathetic fibers get in the maxillary nerve through its ganglionic branches for circulation to the lacrimal gland and also to nerves leaving the ganglion come palatine and also nasal mucous glands (Piagkou et al., 2011). Finally, the ganglion obtain the sympathetic root together postganglionic sorry fibers the arise native the remarkable cervical ganglion and also travel by means of the deep petrosal nerve and nerve of the pterygoid canal. They are dispersed with the postganglionic parasympathetic fibers. Thus, each branch off the PPG consists of sensory, postganglionic parasympathetic, and postganglionic forgiveness fibers.


Understanding the anatomy of the vidian canal is a vital element come the approach and thus the success the the procedure (Fig. 23.1).

The vidian nerve is formed by the confluence the the higher superficial petrosal and also deep petrosal nerves and travels in the pterygoid canal carrying the parasympathetic fibers, which synapse in the pterygopalatine ganglion, and also the postganglionic yarn are dispersed with the branches that the maxillary nerve.

Computed tomography (CT) scans permit for an ext precise evaluation of the place of the vidian nerve to the sphenoid sinus (type 1 and type 2 lying over or ~ above the sphenoid sinus floor and form 3 canal being much more embedded and deep).6

The opened of the vidian canal into the pterygopalatine fossa is uncovered at the junction of the medial pterygoid plate and the floor of the sphenoid sinus and also is lateral to the smaller sized palatovaginal canal that homes the pharyngeal nerve, which runs in a medial to lateral direction.

Understanding the connection of the vidian canal and the palatovaginal canal (lies inferomedial to the vidian canal transmitting the pharyngeal branches the the maxillary artery and also pterygopalatine ganglion and also is regularly mistaken because that the vidian canal) is therefore vital for a successful outcome.


Shu-Ting Chen, Jr-Wei Wu, in development in brain Research, 2020

3.3 The brainstem modulation that trigeminovascular system

The trigeminal ganglion creates a reflex connection with the sphenopalatine ganglion v the TCC come the superior salivatory cell core (SSS) in the pons, namely trigeminal-autonomic reflex (Fig. 1) (Akerman et al., 2011; May and Goadsby, 1999). The preganglionic parasympathetic fibers construct from the SSS in the pontine tegmentum, the efferent parasympathetic fibers transverse the geniculate ganglion however do no synapse, then exit the geniculate ganglion as the greater petrosal nerve (Robbins et al., 2016). The better petrosal nerve passes through the facial canal and enters the pterygoid canal (Robbins et al., 2016). In the pterygoid canal, the efferent parasympathetic fibers join the deep petrosal nerve (a sympathetic nerve) to type the nerve of the pterygoid canal, and finally synapsing in pterygopalatine ganglion (Robbins et al., 2016). This connection provides parasympathetic input come the cranial structures and is responsible because that autonomic symptom of primary headache disorders, such as trigeminal autonomic cephalalgias (Goadsby, 2002; May and also Goadsby, 1999).

The TCC contains second-order neurons, which send projections come the rostral ventromedial medulla (RVM), ventrolateral periaqueductal gray (vlPAG), thalamus, and also other brainstem nuclei (Goadsby et al., 2017a; Weiller et al., 1995). In the brainstem, nociceptive signals space modulated by to decrease input from the RVM and vlPAG (Fields and also Heinricher, 1985). These frameworks then send further ascending projections to cortical and subcortical structures. The central projections of the trigeminovascular device are shown in Fig. 1.


Derald E. Brackmann, Bruce L. Fetterman, in Textbook that Clinical Neurology (Third Edition), 2007

Parasympathetic Nucleus

The general visceral efferent yarn originate from the exceptional salivatory nucleus and also the lacrimal cell nucleus in the dorsal pons and also are carried distally within the nervus intermedius. ~ joining the motor root of the face nerve, two main branches bring the parasympathetic fibers to your destination. In ~ the geniculate ganglion, the better superficial petrosal nerve branches in ~ the hiatus of the face canal and travels anteromedially through the center fossa in ~ the pterygoid canal. Had within this nerve room preganglionic fibers destined because that the lacrimal gland and the minor salivary glands of the sleep cavity, paranasal sinuses, and palate. The deep petrosal nerve, transferring postganglionic sorry fibers, join the better superficial petrosal nerve to type the nerve that the pterygoid canal (vidian nerve). In ~ the pterygopalatine ganglion (found within the pterygopalatine fossa), the parasympathetic fibers synapse with postganglionic neurons, which continue toward your target organs.

The preganglionic fibers because that the submandibular and also sublingual salient glands pass with the geniculate ganglion and also then leave the mastoid segment that the facial nerve in ~ the chorda tympani. The chorda tympani travels through the temporal bone within the canal of Huguier and also enters the infratemporal fossa via the petrotympanic fissure, wherein it joins the lingual nerve (CN V). Within the submandibular ganglion, the parasympathetic yarn synapse v the postganglionic cells the innervate the submandibular and also sublingual outstanding glands.


B.C. Anderson, L.K. McLoon, in Encyclopedia that the Eye, 2010

Parasympathetic innervation come the lacrimal gland

The brainstem neurons, i beg your pardon every an easy anatomy textbook defines as providing rise to the parasympathetic secretomotor nerve fibers of the lacrimal gland, are found within the ventral subgroup the neurons in the exceptional salivatory cell core located in between the root of the face nerve and the premium olive nuclei. The preganglionic parasympathetic secretomotor fibers departure the brainstem in ~ the intermediate root of the facial nerve. The intermediate root joins the motor source of the face nerve and also exits the cranium v the internal acoustic meatus. In ~ the temporal bone, the parasympathetic fibers departure the face nerve in ~ the geniculum and also leave the temporal bone together the higher petrosal nerve. This nerve process anteriorly, crosses the center cranial fossa, and also enters the pterygoid canal whereby it is joined by the deep petrosal nerve, which brings sympathetic nerve fibers that ascended indigenous the superior cervical ganglion by running on the inner carotid artery. These two nerve branches hold together and kind the nerve of the pterygoid canal (formerly dubbed the vidian nerve). The nerve the the pterygoid canal process to the pterygopalatine ganglion, which is linked with V2 in ~ the pterygopalatine fossa. Here in the pterygopalatine ganglion, the preganglionic parasympathetic nerve fibers synapse v neurons that will kind the postganglionic nerve fibers. This secretomotor fibers have actually been explained as coursing v the zygomatic nerve, which runs on the floor and lateral wall surface of the orbit. Eventually, a nerve source anastamosis through the lacrimal nerve forms and carries the postganglionic secretomotor fibers the originated in CNVII to the lacrimal gland. A variety of scientists question this pathway, as it is extremely complex and the anastamosis in between the zygomatic and also lacrimal nerve is often nonexistent. In addition, section of the connecting ramus between the zygomatic and also lacrimal nerves walk not minimize lacrimation.

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Recent studies using contemporary tract-tracing techniques have demonstrated that, in fact, over there is a direct pathway native the pterygopalatine ganglion to the lacrimal gland via a retro-orbital autonomic plexus. In humans and also in the nonhuman primates, 5–10 rami can be traced straight from the pterygopalatine ganglion come the retro-orbital nerve plexus, and rami indigenous this plexus are easily traced directly to the lacrimal gland. In various other studies, nerve rami were followed that passed directly from the pterygopalatine ganglion come the lacrimal gland. This studies demonstrate that, contrary to existing dogma, pterygopalatine postganglionic parasympathetic efferents food to the lacrimal gland without utilizing branches the the maxillary (zygomatic branch) nerve as a route.