Is cranial nerve VIII motor or sensory?
Special sensory
Cranial nerve VIII is actually composed of what two nerves?
Vestibular and cochlear nerves
What is the nucleus of termination for the vestibular nerve?
Vestibular nuclear complex (superior, medial, lateral, and inferior)
What is the eponym for the superior vestibular nucleus?
Bechterew
What is the eponym for the medial vestibular nucleus?
Schwalbe
What is the eponym for the lateral vestibular nucleus?
Deiter
Where are the cell bodies for the vestibular nerve located?
Vestibular ganglion (superior and inferior parts)
Where is the vestibular ganglion located?
Internal acoustic meatus
What is the nucleus of termination for the cochlear nerve?
Cochlear nuclei (anterior and posterior parts)
Where are the cell bodies located for the cochlear nerve?
Spiral ganglion
What is the location of the spiral ganglion?
Within the cochlea
Peripheral processes (short dendrites) extend from the spiral ganglion to where first?
Spiral organ (organ of Corti)
Axons of the cochlear nerve terminate where?
On the two cochlear nuclei
From the cochlear nuclei, where do the axons synapse after they cross the brainstem and what is formed?
Trapezoid nuclei and lateral lemniscus is formed
From the lateral lemniscus, where will fibers travel to in the cochlear pathway?
Either the inferior colliculus or the medial geniculate body of the thalamus
What is the apparent origin of cranial nerve VIII?
Cerebellopontine recess/angle
Most vestibular nerve fibers of cranial nerve VIII terminate where?
In the medial vestibular nucleus (Schwalbe)
Some of the vestibular nerve fibers of cranial nerve VIII travel directly to the cerebellum by way of which peduncle?
Inferior cerebellar peduncle
The vestibulocochlear nerve travels through what area to the internal acoustic meatus where it enters along with the facial nerve?
Posterior cranial fossa
Which nerve of cranial nerve VIII contains more fibers?
Cochlear (30-40,000)
What branch of the vestibular nerve is larger?
Superior branch
What makes up the inferior branch of the vestibular nerve?
Saccular nerve and posterior ampullary nerve
What area of the ear is supplied by both the inferior and superior branches of the vestibular nerve?
Saccule
What forms the superior branch of the vestibular nerve?
Lateral and anterior ampullary nerves
What nerves supply the utricle?
Branch from the lateral ampullary nerve and a branch directly off the superior branch
What does Voit’s nerve supply?
Saccule (branch from the superior branch of the vestibular nerve)
What is a unilateral tumor of Schwann cells associated with cranial nerve VIII leading to hearing and equilibrium issues, as well as major headaches?
Acoustic neuroma
What is tinnitus?
Ringing sensation in the ears
Tinnitus could be a 1st sign of what condition?
Ménière’s disease
What kind of hearing loss do cochlear implants treat?
Sensorineural hearing loss
How can we differentiate vestibular disease (vertigo) from cervicogenic vertigo?
If the swivel chair spinning while stabilizing the patient’s head reproduces the vertigo, it is most likely cervicogenic & we are able to help them via neck adjustment
What is another name for the superior semicircular duct/canal?
Anterior
What is the nucleus of origin of cranial nerve IX?
Nucleus ambiguus (superior part)
The muscles supplied by the nucleus ambiguus are derived from what embryologic structures?
Branchial arches (therefore are branchiomotor)
What are the two nuclei of termination for cranial nerve IX?
Spinal nucleus of trigeminal and solitary nucleus (nucleus solitarius)
From where do the preganglionic parasympathetic fibers of cranial nerve IX arise?
Inferior salivary nucleus
What are the two peripheral ganglia associated with cranial nerve IX?
A smaller superior ganglion and an inferior ganglion
Where do autonomic fibers from the glossopharyngeal nerve synapse?
Otic ganglion
General sensory information is carried in cranial nerve IX from which locations?
Nasopharynx, oropharynx, portion of the tongue posterior to the sulcus terminalis, uvula, palatine tonsils, and tympanic cavity
Where do general sensory information from cranial nerve IX synapse?
Spinal nucleus of the trigeminal nerve
What is the cell body location for the general sensory information carried in cranial nerve IX?
Notes say inferior ganglion (but there is some discrepancy among sources; some say superior)
What is the nucleus of termination for taste information in cranial nerve IX?
Solitary nucleus (superior part)
What is the cell body location for taste sensory information of cranial nerve IX?
Inferior ganglion
What is the nucleus of termination for visceral afferent information of cranial nerve IX?
Solitary nucleus (inferior part)
What is the cell body location for visceral afferent information of cranial nerve IX?
Inferior ganglion
Visceral afferent cells of cranial nerve IX carry information from what locations?
Carotid sinus and carotid body (baroreceptors sensitive to pressure changes)
The nucleus ambiguus contributes lower motor neurons to which three cranial nerves?
IX, X, and XI
What muscle is supplied by cranial nerve IX?
Stylopharyngeus
What types of fibers make up the mixed cranial nerve IX?
Motor, sensory, autonomic
From the otic ganglion, postganglionic parasympathetic fibers of cranial nerve IX influence what glands?
Parotid, buccal, and inferior labial glands
What is the apparent origin of cranial nerve IX?
Lateral aspect of the superior part of the medulla oblongata
Which cranial nerves do not have discernible trunks that come out as apparent origins but instead as a series of rootlets?
IX, X, XI, XII
From where do preganglionic parasympathetic axons of cranial nerve IX arise to then synapse in the otic ganglion?
Inferior salivary nucleus
The glossopharyngeal nerve exits the skull via what osseous opening?
Jugular foramen
Which ganglion of cranial nerve IX is located inside the cranium?
Superior ganglion
Which ganglion of cranial nerve IX is located beyond the jugular foramen, outside the cranium?
Inferior ganglion
Preganglionic parasympathetic and/or sensory fibers from cranial nerve IX enter the tympanic cavity by way of what opening?
Tympanic canaliculus
What types of fibers make up the tympanic plexus (cranial nerve IX)?
General sensory, preganglionic parasympathetic, and postganglionic sympathetic fibers
From where does the tympanic nerve arise?
Inferior ganglion
The tympanic plexus carries somatosensory information from what areas?
Tympanic cavity, pharyngotympanic (Eustachian) tube, mastoid air cells
What forms the lesser petrosal nerve?
Preganglionic parasympathetic fibers that travel through the tympanic plexus
To where does the lesser petrosal nerve travel?
Otic ganglion
What types of fibers are carried in the tympanic nerve BEFORE it enters the tympanic cavity?
Preganglionic parasympathetic and sensory fibers
Does the tympanic nerve go to the otic ganglion?
NO; the lesser petrosal nerve does (from that sequence)
Postganglionic parasympathetic fibers from the otic ganglion are carried in branches of what other cranial nerve to which glands?
Cranial nerve V3 (mandibular division) to the parotid, buccal, and inferior labial glands
The carotid branch of the glossopharyngeal nerve carries afferent information from what locations?
Chemoreceptors in the carotid body and baroreceptors in the carotid sinus (similar to the vagus nerve)
What branches of cranial nerve IX convey sensory information from the mucosa of the pharynx?
Pharyngeal branches
What branch of cranial nerve IX supplies the stylopharyngeus muscle?
Muscular branch
What is the location of the carotid branch of cranial nerve IX?
Ascends from below and enters the nerve at the inferior ganglion
What are the two branches of cranial nerve IX that reach the oral cavity?
Tonsillar and lingual branches
The tonsillar branches of cranial nerve IX convey sensory information from what locations?
Palatine tonsils and oral mucosa
The lingual branches of cranial nerve IX carry general sensory and taste information from what areas?
Tongue (posterior to the sulcus terminalis)
The lesser petrosal nerve travels through what opening to get to the otic ganglion?
Lesser petrosal canal
What types of taste are lost when the glossopharyngeal nerve is affected?
Bitter and sour (those tastebuds posterior to the sulcus terminalis)
What is a simple test used for the glossopharyngeal nerve?
Gag reflex with a long Q-tip testing the pharyngeal arches
What action becomes difficult with impairment to cranial nerve IX?
Swallowing
In the tympanic cavity, the tympanic nerve receives postganglionic sympathetic fibers from what location?
Superior cervical ganglion