Anatomy of the Vessels and Nerves of the Head and Neck (Angioneurology) - Chornokulskyi S.T. 2009

Nerves of the Head and Neck
Glossopharyngeal nerve

[IX] n. glossopharyngeus (Fig. 43).

It is a mixed nerve containing three nuclei:

— Nucleus of the solitary tract (nuc. tractus solitarii), which is responsible for general and gustatory sensitivity, shared with the VII and X cranial nerve pairs;

— Ambiguous nucleus (nuc. ambiguus), which is somatomotor, shared with the X and XI cranial nerve pairs;

— Inferior salivatory nucleus (nuc. salivatorius inferior), which is parasympathetic.

The rootlets (4–5) of the nerve emerge posterior to the olive and superior to the rootlets of the X and XI cranial nerve pairs (the so-called "vagus group" of nerves comprising the IX, X, and XI pairs).

Fiber COMPOSITION OF THE IX cranial nerve ROOT:

✵ Axons of pseudounipolar Neurons from the superior and inferior ganglia of the IX nerve, projecting to nuc. tractus solitarii;

✵ Axons of somatomotor neurons from the ambiguous nucleus;

✵ Axons of autonomic neurons (preganglionic parasympathetic fibers) from the inferior salivatory nucleus.

Within the jugular foramen, toward which the root of the IX pair is directed, lies the superior ganglion (ganglion superius), while the inferior ganglion (ganglion inferius) is located in the petrosal fossa. Inferior to these ganglia, the trunk of the glossopharyngeal nerve begins, within whose fiber composition the dendrites of pseudounipolar neurons appear. The axons of somatomotor and parasympathetic neurons continue along the nerve trunk unchanged.

After emerging through the anterior compartment of the foramen jugulare alongside the IX, X, and XI cranial nerve pairs, the glossopharyngeal nerve runs inferiorly between the Internal Carotid Artery and the Internal jugular vein, and, forming an arch, reaches the root of the Tongue. The axons of somatomotor neurons branch off as the stylopharyngeal Muscle branch (r. musculi stylopharyngei).

The remaining branches are as follows:

1. Tympanic nerve (n. tympanicus) (Jacobson's anastomosis), which branches off inferior to the inferior ganglion and contains sensory and preganglionic parasympathetic fibers.

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Fig. 42. Diagram of the 1st (bipolar) neuron of the Vestibulocochlear nerve:

1 - sensory Hair Cells;

2 - supporting Cell;

3, 9 - dendrite of the bipolar neuron;

4 - bipolar neuron of the ganglion;

5 - axon of the bipolar neuron;

6 - surface of the Brain;

7 - ascending branch;

8 - descending branch

Through the tympanic canaliculus, the nerve reaches the medial wall of the tympanic cavity, where it contributes all of its sensory and a small fraction of its parasympathetic fibers to the tympanic plexus (plexus tympanicus). The preganglionic parasympathetic fibers of the nerve synapse in the tympanic ganglion (ganglion tympanicum) to form its radix parasympathica. The sensory root (radix sensoria) of the ganglion consists of sensory fibers from n. tympanicus, whereas the sympathetic root (radix sympathica) originates from the caroticotympanic nerves branching from the internal carotid plexus (plexus caroticus internus). The Branches of the ganglion provide innervation (including secretory) to the mucosa of the tympanic cavity, the auditory tube, and the mastoid air cells. The majority of the parasympathetic fibers of the tympanic nerve leave the tympanic cavity via the hiatus for the lesser petrosal nerve and are designated accordingly as the lesser petrosal nerve (n. petrosus minor). The latter exits the cranial cavity by piercing the sphenopetrosal synchondrosis and reaches the otic ganglion (see p. 83).

The tympanic nerve has a communicating branch with the auricular branch of the Vagus nerve.

3. Pharyngeal branches (rr. pharyngeales) reach the lateral walls of the Pharynx and, together with the pharyngeal branches of the vagus nerve and the Sympathetic trunk, form the pharyngeal plexus (plexus pharyngeus).

4. The carotid sinus branch (r. sinus carotici) runs toward the wall of the carotid sinus, which contains the carotid body (glomus caroticum). This paraganglion is located at the bifurcation of the common carotid artery.

5. Tonsillar branches (rr. tonsillares) supply the mucosa of the palatine Tonsils and arches, as well as the soft palate.

6. Lingual branches (rr. linguales) innervate the mucosa of the posterior third of the tongue (up to the epiglottis) with taste and general sensory fibers.

The glossopharyngeal nerve also has communicating branches with the chorda tympani and the auriculotemporal nerve.

Fig. 43. Branches of the glossopharyngeal nerve (schematic):

1 - Midbrain (mesencephalon);

2 - Pons;

3 - Cerebellum;

4 - Medulla Oblongata;

5 - jugular foramen (foramen jugulare);

6 - superior ganglion of the glossopharyngeal nerve (ganglion superius);

7 - inferior ganglion of the glossopharyngeal nerve (ganglion inferius);

8 - tympanic canaliculus (canaliculus tympanicus);

9 - tympanic cavity (cavitas tympanica);

10 - hiatus for the lesser petrosal nerve (hiatus canalis n. petrosi minoris);

11 - otic ganglion (ganglion oticum);

12 - parotid gland (glandula parotidea);

13 - mandibular nerve (n. mandibularis);

14 - auriculotemporal nerve (n. auriculotemporalis);

15 - tongue (lingua);

16 - palatine tonsil (tonsilla palatina);

17 - mucous membrane of the pharynx (tunica mucosa pharyngis);

18 - pharyngeal constrictors (mm. constrictores pharyngis);

19 - stylopharyngeus muscle (m. stylopharyngeus) and ramus m. stylopharyngei;

20 - common carotid artery (a. carotis communis);

21 - nucleus ambiguus (n. ambiguus);

22 - nucleus of the solitary tract (nuc. tractus solitarii);

23 - inferior salivatory nucleus (nuc. salivatorius inferior);

24 - pharyngeal branches (rr. pharyngei);

25 - carotid sinus branch (r. sinus carotici);

26 - vallate papillae (papillae vallatae);

27 - preganglionic parasympathetic fibers within the tympanic nerve;

28 - preganglionic parasympathetic fibers within the lesser petrosal nerve;

29 - postganglionic parasympathetic fibers to the parotid gland;

30 - lingual branches (rr. linguales);

31 - tonsillar branches (rr. tonsillares);

14, 17, 31 - general sensory fibers;

19 - motor fibers of ramus m. stylopharyngei;

30 - special visceral afferent (taste) fibers;

27, 28 - preganglionic parasympathetic fibers;

29 - postganglionic parasympathetic fibers

Fig. 43a. Parasympathetic ganglia of the HEAD and their parasympathetic roots:

VII - superior salivatory nucleus (nuc. salivatorius superior) and lacrimal nucleus (n. lacrimalis);

1 - geniculate ganglion (ganglion geniculi);

2 - greater petrosal nerve (n. petrosus major);

3 - chorda tympani (chorda tympani);

4 - Facial Nerve (n. facialis);

5 - trigeminal ganglion (ganglion trigeminale);

III - accessory nucleus of Oculomotor nerve

(nuc. accessorius n. oculomotorii) and unpaired median nucleus (nuc. impar);

6 - oculomotor nerve (n. oculomotorius);

7 - lacrimal nerve (n. lacrimalis);

8 - orbital branches (rr. orbitales) to the lacrimal gland;

9 - nasociliary nerve (n. nasociliaris);

10 - ciliary ganglion (ganglion ciliare);

11 - zygomatic nerve (n. zygomaticus);

12 - maxillary nerve (n. maxillaris);

13 - pterygopalatine ganglion (ganglion pterygopalatinum);

14 - lingual nerve (n. lingualis);

15 - otic ganglion (ganglion oticum);

16 - mandibular nerve (n. mandibularis);

17 - auriculotemporal nerve (n. auriculotemporalis);

18 - parotid branches (rr. parotidei);

IX - inferior salivatory nucleus (nuc. salivatorius inferior);

19 - preganglionic parasympathetic fibers to ganglion tympanicum and ganglion oticum;

20 - lesser petrosal nerve (n. petrosus minor);

21 - submandibular ganglion (ganglion submandibulare);

22,23 - postganglionic parasympathetic fibers to the submandibular and sublingual glands