Midterm III: Cranial Nerves III, IV, VI, IX (Ben) Flashcards
What are CN III’s two nuclei?
What type of nuclei are they?
Where are they?
- Edinger-Westphal (GVM)
- Oculomotor Nucleus (SM)
Both in the midbrain, superior collicle level.
What is the brain exit of CN III?
Dural exit?
Skull exit?
brain - interpeduncular fossa
dural - cavernous sinus wall
skull - superior orbital fissure
What are the 2 branches of the oculomotor nerve?
-
Superior
- superior rectus
- levator palpebrae superioris
-
Inferior
- inferior/medial rectus
- inf. oblique
- pre-synaptic GVM fibers
Where do CN III’s general visceromotor fibers end?
- GVM fibers end in the Ciliary Ganglion (on multi-polar neurons)
What does the superior branch of CN III supply?
- levator palpebrae superioris
- superior rectus
What does the inferior branch of CN III supply?
- medial rectus
- inferior rectus
- inferior oblique
- presynaptic GVM fibers to ciliary ganglion
What are the postganglionic parasympathetic fibers originating from CN III called?
What do they innervate?
E-W Nucleus fibers synapse in ciliary ganglion and go on to form…
Short Ciliary Nerve
which innervates…
- Ciliaris Muscle
- Sphincter Pupillae
What is the nucleus for CN IV?
Where is it?
Trochlear Nucleus
(SM, crossed)
- in the midbrain, inferior collicle level
What is the brain exit of CN IV?
Dural exit?
Skull exit?
brain - below inferior colliculi
dural - lateral wall cavernous sinus
skull - superior orbital fissure
What muscle is innervated by CN IV?
superior oblique
What is the nucleus of CN VI?
Where is it?
Abducens Nucleus
(SM)
- in the pons
What is the brain exit of CN VI?
Dural exit?
Skull exit?
brain - ponto-medullary junction, both sides foramen caecum
dural - cavernous sinus (via Dorello’s canal)
skull - Superior Orbital Fissure
What muscle does CN VI innervate?
lateral rectus
What are the 5 nuclei of the glossopharyngeal nerve (CN IX)?
What types of nuclei are they?
(Extra: where are they?)
-
Inferior Salivatory Nucleus - GVM
- (P-M junction)
- Nucleus of Lateral Ala Cinerea - GVS
- Solitary Nucleus - SVS
- Nucleus Ambiguus - BM
- Spinal Trigeminal Tract - GSS
(2-5 in open medulla)
InS.LAC.Sol.Am.STri
What is the brain exit of CN IX?
Dural exit?
Skull exit?
brain - lateral parolivary sulcus
dural - jugular foramen
skull - jugular foramen
Which branchial arch is the glossopharyngeal nerve associated with?
3rd branchial (pharyngeal) arch
What branchial arch-related muscle does CN IX innervate?
stylopharyngeus
What are the 4 main branches of the glossopharyngeal nerve?
(3 branches + 1 plexus)
- Tympanic Nerve (of Jacobson)
- Communicating Branch to Auricular Branch of Vagus (Arnold’s Nerve)
- Carotid Branch (Hering’s Nerve)
- Pharyngeal Plexus
Tym.Comm.Car.Phar
Where does the tympanic nerve (of Jacobson) start and end?
and how does it get there?
Start - Inferior Ganglion of CN IX, just outside of jugular foramen
…hooks back into skull via Tympanic Canaliculus
End - Tympanic Plexus, within tympanic cavity, giving 3 branches
What 3 branches does the tympanic nerve give after its tympanic plexus within the tympanic cavity?
- Lesser Petrosal Nerve
- Deep Petrosal Nerve
- Tympanic Branches (—> tymp. cavity mucosa)
How do the inferior salivatory nucleus‘ fibers reach their target?
And what is the target?
GVM fibers from the inf. salivatory nucleus travel…
- via CN IX to its inferior ganglion
- as tympanic nerve to tympanic plexus
- as lesser petrosal nerve to otic ganglion
- as postsynaptic parasympathetic fibers to the parotid gland
Where does the carotid branch of CN IX begin?
Ganglion?
End?
(in the direction of transmission)
Begin - baro-/chemoreceptors of carotid body
Ganglion - Inferior Ganglion of CN IX (pseudounipolar, not synapse)
End - Lateral Ala Cinerea Nucleus (GVS)
What is the branchiomotor nucleus of CN IX and what does it innervate?
Where do its fibers synapse?
Nucleus Ambiguus
- innervates pharyngeal muscles via pharyngeal plexus
- directly innervates stylopharyngeus via its own branch
- its fibers pass through both sup/inf glossopharyngeal ganglia without synapsing
What is the general somatosensory nucleus of CN IX?
Where do its fibers synapse?
Spinal Trigeminal Nucleus
- synapse in the superior ganglion of CN IX
(just inside the jugular foramen)
What does the spinal trigeminal tract innervate via the glossopharyngeal nerve?
GSS innervation to…
- Oropharynx
- Pharyngeal Tonsil
- Tongue, Post. 1/3
- Tympanic Cavity
OPTT
To where does CN IX give taste sensation?
Via what ganglion?
And to what nucleus?
- Posterior 1/3 Tongue
- Inferior Ganglion of CN IX
- Solitary Nucleus
