IX Cranial Nerve

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The Glossopharyngeal Nerve
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Figure 14.27
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Glossopharyngeal

• Fibers emerge from the medulla, leave the skull
  via the jugular foramen, and run to the throat
• Nerve IX is a mixed nerve with motor and sensory
  functions
• Motor innervates part of the tongue and
  pharynx, and provides motor fibers to the parotid
  salivary gland
• Sensory fibers conduct taste and general
  sensory impulses from the tongue and pharynx

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Glossopharyngeal nerve

• Leave the skull through jugular foramen
• Passes forwards between internal jugular vein and
  external carotid artery.
• Deep to styloid process.
• Between external and internal carotid arteries at
  posterior border of stylopharyngeus then lateral
  to it.
• Reaches the pharynx by passing between middle and
  inferior constrictor, deep to hyoglossus, where
  it breaks into terminal branches.

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Glossopharyngeal Nerve

• A mixed nerve (sensory, motor, parasympathetic)
• Emerges from the ventral surface of the medulla
  oblongata
• Runs laterally in the posterior cranial fossa
• Leaves the skull by passing through the central
  part of the jugular foramen
• Has superior and inferior ganglia, that are
  located within the jugular foramen.

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• At its exit from the skull, it passes forward
  between the internal jugular vein and internal
  carotid artery, within the carotid sheath
• Descends to the lower border of the
  stylopharyngeus muscle.
• Then curves forward around the stylopharyngeus
  and
• Passes through the gap between the superior and
  middle constrictor muscles of the pharynx

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• Passes under cover of the hyoglossus muscle
• Distributed to the
• Palatine tonsil
• Mucous membrane of the fauces and base of the
  tongue,
• Mucous glands of the mouth

P
F
PT
T
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Gloosopharyngeal nerve

• jf--jugular foramen
• sg--superior ganglion
• ig--inferior ganglion
• tp--tympanic plexus
• lpn--lesser petrosal nerve
• fo--foramen ovale
• og--otic ganglion
• pg--parotid gland
• sp--nerve to stylopharyngeus muscle
• pb--pharyngeal branch
• ncbcs--nerve to carotid body carotid sinus
• Red solid -- motor
• Red dotted -- parasympathetic
• Yellow -- sensory (afferent)

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Glossopharyngeal nerve

• Ganglia
• Superior ganglion small, with no branches.
• Inferior ganglion, large carries general
  sensations from pharynx, soft palate and fauces.

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Nerve IX Glossopharyngeal
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• Detail on Glossopharyngeal (IX) Function
• Motor to stylopharyngeus muscle.
• Parasympathetic secretomotor fibers to parotid
  gland.
• Sensory to pharynx, tonsils, and posterior 1/3 of
  tongue.
• Taste fibers for posterior 1/3 of tongue.

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Glossopharyngeal Nerve (IX)

• Innervates structures of the tongue and pharynx

Facial nerve (VII)
Vestibulocochlear nerve (VIII)
Glossopharyngeal nerve (IX)
Vagus nerve (X)
Accessory nerve (XI)
Hypoglossal nerve (XII)
Table 14.3 (9 of 12)
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COURSE

• It arises from the medulla ,and then passes
  through the Jugular foramen of the skull ,between
  the IJV and the ICA.
• It is accompanied by Cranial nerves X and XI.
• It follows the ICA.

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• It passes under the Styloid process ,and then
  into the pharynx ,where it lies over the
  Stylopharyngeus muscle and the middle pharyngeal
  constrictor muscle.
• It then passes undercover of the of the
  Hyoglossus muscle ,and is then distributed to the
  Palatine tonsil,and mucus memb of fauces,base of
  tongue ,and mucus glands of the mouth.

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Course of Glossopharyngeal Nerve

• The glossopharyngeal nerve arises by 4-5 rootlets
  from the posterolateral sulcus of medulla.
• It leaves the skull through the jugular foramen.
• While it lies in jugular foramen it has 2 small
  sensory ganglia (superior and inferior).
• It descends downwards inside the upper carotid
  sheath superficial to vagus nerve and between IJV
  ICA lying deep to the styloid process and
  muscle attached to it.
• Then it leaves the carotid sheath and passes
  forwards with stylopharyngeus muscle between the
  ICA ECA.
• Ascends deep to hyoglossus to reach the tongue.
• Termination it ends into terminal branches
  supplying the mucous membranes of pharynx, tonsil
  and the posterior 1/3 of tongue.

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IX Glossopharyngeal Nerve

• It is a mixed N. ,attached lateral to olive in
  rostral medulla and leaves the skull through
  jugular foramen.
• It receives afferent Fs. From 1-Receptors of
  general sensation in pharynx, post.1/3 of tongue,
  eustachian tube middle ear.
  2- Taste buds of pharynx post.1/3 of
  tongue. 3- Chemoreceptors
  in carotid body Baroreceptors in the carotid
  sinus.

Glossopharyngeal nerve nuclei their central
connections
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Branches of the Glossopharyngeal Nerve

• 1. Meningeal branch (sensory)
• Arises from the intracranial part of the
  glossopharyngeal
• nerve.
• Sensory nerve supplies meninges of posterior
  cranial
• fossa.

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Branches of the Glossopharyngeal Nerve

• 2. Tympanic branch (Jacobson's Nerve-
  parasympathetic nerve)
• Preganglionic parasympathetic nerve to
  parotid gland.
• Arises from the inferior ganglion of the
  glossopharyngeal nerve in
• the jugular fossa.
• Course of the tympanic nerve
• It passes through the tympanic canaliculus.
• It reaches the middle ear cavity where it
  breaks to form the
• tympanic plexus.
• Lesser superficial petrosal nerve arises from
  the tympanic plexus
• and reaches the middle cranial fossa.
• Then lesser superficial petrosal nerve passes
  through the foramen
• ovale to reach infratemporal fossa to relay
  in the otic ganglion.
• The postganglionic fibers joint the
  auriculotemporal to supply the
• parotid gland.

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Branches of the Glossopharyngeal Nerve
3. Carotid branch (sensory) sensory nerve to the
carotid sinus and carotid body. 4. Nerve to
stylopharyngeus muscle (motor) motor
nerve to stylopharyngeus muscle.
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Branches of the Glossopharyngeal Nerve
5. Pharyngeal branches (sensory) they enter the
formation of the pharyngeal plexus and
supplies the mucous membrane of
pharynx. The pharyngeal plexus receives also
a. Motor fibers (the pharyngeal branches of
vagus nerve). b. Sympathetic
fibers(the pharyngeal branches of
the superior cervical ganglion)
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Branches of the Glossopharyngeal Nerve
6. Tonsillar branches (sensory) to the palatine
tonsil. 7. Lingual branches (sensory) terminal
branches to mucous membrane of the
posterior 1/3 rd of the tongue (taste and
general sensation).
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Branches

• Tympanic branch Passes to the tympanic plexus in
  the middle ear and
• Supplies sensory fibers to the plexus
• Carries preganglionic parasympathetic fibers,
  that leave the plexus as lesser petrosal nerve
  and synapse in the otic ganglion
• Carotid branch carries sensory fibers from the
  carotid sinus carotid body
• Muscular branch to the stylopharyngeus muscle

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Branches contd

• Lingual branch passes to the posterior third of
  the tongue and the circumvellate papillae
• Pharyngeal branches carry sensory fibers to the
  pharyngeal plexus, which supplies the mucous
  membrane of the pharynx, tonsil and soft palate
• Communicates with the
• Vagus facial nerves
• Superior cervical ganglion of the sympathetic
  chain

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Branches.

• Of communications
• Inferior ganglion and
• superior cervical sympathetic ganglion.
• Superior ganglion and auricular branch of vagus.
• Its trunk and facial nerve at stylomastoid foramen

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Branches.

• Of distribution
• Tympanic.
• Stylopharyngeus.
• Pharyngeal.
• Tonsillar.
• Lingual .

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IMPORTANT BRANCHES

• The Tympanic br.to the tympanic plexus in the
  middle ear.
• Lesser petrosal N arises from this plexus and
  passes to the parotid gland.
• Carotid br,which carries sensory fibres .
• Nerve to the Stylopharyngeus
• Pharyngeal brs
• Lingual br ,which supplies the post 1/3rd of the
  tongue.

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• C/C
• The general sensory component mediates the
  afferent limb of pharyngeal reflex in which
  touching the back of the pharynx elicits the gag
  reflex . This is used to test the
  Glossopharyngeal nerve clinically.

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IX Glossopharyngeal Nerve Fibres
1-Afferent Fs. for general sensation end in
trigeminal sensory nucleus.
-Fibres carrying touch sensation
from back of tongue pharynx are important for
mediating gag reflex, through connection with
nucleus ambiguus hypoglossal nucleus.
2-Afferent visceral (chemo- baroreceptors)
taste Fs. end in nucleus solitarius
of medulla.
Glossopharyngeal nerve nuclei
their central connections. Red motor,
brownparasymp.,bluesensory
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IX Glossopharyngeal Nerve Fibres
3-Efferent motor Fibres
arises from its motor nucleus in the rostral
part of nucleus ambiguus of medulla to supply
stylopharyngeus involved in swallowing.
4-Efferent Parasympathetic Fibres arises from
inferior salivary nucleus of rostral medulla to
synapse in otic ganglion, then via
post-ganglionic Fs.innervate parotid gland.
Glossopharyngeal nerve nuclei
their central connections. Red motor,
brownparasymp.,bluesensory
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Nucleus ambiguus (SVE)

• Branchial motor to stylopharyngeus
• 2. Inferior salivary nucleus (GVE)
• to parotid gland (via otic ganglion)

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3. Spinal trigeminal nucleus

• Somatic sensory from outer ear (superior
  ganglion of IX)
• 4. Nucleus of the solitary tract
• Visceral sensory from carotid body and sinus,
  mucosa of pharynx, posterior tongue, middle ear
  (inferior ganglion of IX)
• Visceral sensory from taste buds on posterior
  third of tongue (inferior ganglion of IX)

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Glossopharyngeal nerve (?)

• Components of fibers
• SVE fibers originate from nucleus ambiguus, and
  supply stylopharygeus
• GVE fibers arise from inferior salivatory
  nucleus and ralyed in otic ganglion, the
  postganglionic fibers supply parotid gland
• SVA fibers arise from the cells of inferior
  ganglion, the central processes of these cells
  terminate in nucleus of solitary tract, the
  peripheral processes supply the taste buds on
  posterior third of tongue
• GVA fibers visceral sensation from mucosa of
  posterior third of tongue, pharynx, auditory tube
  and tympanic cavity, carotid sinus and glomus,
  and end by synapsing with cells of nucleus of
  solitary tract
• GSA fibers sensation from skin of posterior
  surface of auricle and

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• Course leaves the skull via jugular foramen
• Branches
• Lingual branches to taste buds and mucosa of
  posterior third of tongue
• Pharyngeal branches take part in forming the
  pharyngeal plexus
• Tympanic nerve GVE fibers via tympanic and
  lesser petrosal nerves to otic ganglion, with
  postganglionic fibers via auriculotemporal (?3)
  to parotid gland
• Carotid sinus branch innervations to both
  carotid sinus and glomus
• Others tonsillar and stylophayngeal branches
• Otic ganglion situated just below foramen ovale

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Glossopharyngeal Nerve

• Modalities
• SVM
• From
• Nucleus ambiguous.
• To
• Stylopharyngeus.

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Glossopharyngeal Nerve

• Modalities
• GVS
• From
• Carotid body.
• Carotid sinus.

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Glossopharyngeal Nerve

• Modalities
• GVM
• Preganglionics
• From
• Inferior salivatory nucleus.
• To
• Otic ganglion.
• Postganglionics
• To
• Parotid gland.

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Glossopharyngeal Nerve

• Modalities
• GSS
• From
• Posterior 1/3 of tongue.
• External ear.
• Middle ear cavity.

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Glossopharyngeal Nerve

• Modalities
• SVS
• From
• Posterior 1/3 of tongue (taste).

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Functions

• Receives general sensory fibers from the
  posterior ? of the tongue, tonsil, pharynx,
  middle ear and carotid sinus.
• Receives special sensory (taste) fibers from the
  posterior ? of the tongue and the circumvellate
  papillae
• Supplies parasympathetic fibres to the parotid
  gland via the otic ganglion
• Supplies motor fibers to stylopharygeus muscle
• Contributes sensory fibers to the pharyngeal
  plexus

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Table 13.2
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Cranial nerves

• Glossopharyngeal Nerve (CN IX)
• Functions Sensory (general somatic afferent,
  special visceral afferent, general visceral
  afferent), motor (special visceral efferent), and
  parasympathetic (general visceral efferent) for
  derivatives of the 3rd pharyngeal arch.
• Nuclei Four nuclei in the medulla send or
  receive fibers via CN IX two motor and two
  sensory. Three of these nuclei are shared with CN
  X.
• The glossopharyngeal nerve (CN IX) emerges from
  the lateral aspect of the medulla and passes
  anterolaterally to leave the cranium through the
  anterior aspect of the jugular. At this foramen
  are superior and inferior (sensory) ganglia,
  which contain the pseudounipolar cell bodies for
  the afferent components of the nerve. CN IX
  follows the stylopharyngeus, the only muscle the
  nerve supplies, and passes between the superior
  and the middle constrictor muscles of the pharynx
  to reach the oropharynx and tongue. It
  contributes sensory fibers to the pharyngeal
  plexus of nerves.
• CN IX is afferent from the tongue and pharynx
  (hence its name) and efferent to the
  stylopharyngeus and parotid gland.
• Branchial Motor Motor fibers pass to one muscle,
  the stylopharyngeus, derived from the 3rd
  pharyngeal arch.
• Parasympathetic (Visceral Motor)
• Following a circuitous route initially involving
  the tympanic nerve, presynaptic parasympathetic
  fibers are provided to the otic ganglion for
  innervation of the parotid gland. The otic
  ganglion is associated with the mandibular nerve
  (CN V3), branches of which convey the
  postsynaptic parasympathetic fibers to the
  parotid gland .
• Sensory (General Sensory)
• The general sensory branches of CN IX are as
  follows The tympanic nerve. The carotid sinus
  nerve to the carotid sinus, a baro- (presso)
  receptor sensitive to changes in blood pressure,
  and the carotid body, a chemoreceptor sensitive
  to blood gas (oxygen and carbon dioxide levels).
• The pharyngeal, tonsillar, and lingual nerves to
  the mucosa of the oropharynx and isthmus of the
  fauces (L. throat), including palatine tonsil,
  soft palate, and posterior third of the tongue.
  In addition to general sensation (touch, pain,
  temperature), tactile (actual or threatened)
  stimuli determined to be unusual or unpleasant
  here may evoke the gag reflex or even vomiting.
• Taste (Special Sensory) Taste fibers are conveyed
  from the posterior third of the tongue to the
  sensory ganglia.

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Lesion of the Glossopharyngeal Nerve

1. Loss of taste and general sensation from the
   posterior 1/3 of the tongue.
2. Loss of sensation in the pharynx.
3. Some pharyngeal weakness.
4. Loss of salivation from the parotid gland.

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Glossopharyngeal Nerve Lesions

• Glossopharyngeal nerve lesions produce
• Difficulty in swallowing
• Loss of general sensation over the posterior
  one-third of the tongue, palate, and pharynx
• Loss of taste sensation over the posterior
  one-third of the tongue and palate
• Dysfunction of the parotid gland
• Loss of the gag reflex

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The Glossopharyngeal Nerve (IX)

• The glossopharyngeal nerve is a mixed nerve
  containing a. Sensory fibers.
• b. Parasympathetic fibers
• c. Motor fibers.
• It is more important as sensory than as a motor
  nerve.
• Origin from posterolateral sulcus of medulla.

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Nuclei of Glossopharyngeal Nerve

• It has three nuclei
• The upper part of nucleus ambiguous it lies in
  the medulla (motor function).
• The inferior salivary nucleus it lies in the
  medulla (parasympathetic function).
• The solitary nucleus it lies in the medulla
  (sensory function).

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IX GLOSSOPHARYNGEAL

• carries information from the head and neck to the
  brainstem.
• Information about blood pressure (baroreceptors)

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CN IX glossopharyngeal nerve
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CN IX and X