Gross Anatomy of the Facial Nerve Flashcards
large motor root of CN VII caries what fibers
SVE
smaller root of CN VII
nervus intermedius with GVE, SA, GSA, and GVA fibers
intraosseous course of facial nerve
from posterior cranial (first to emerge) through the internal acoustic meatus – courses through the facial canal - which takes a lateral course and more inferior –> leaves at the styloimastoid foramen which is between the styloid process and mastoid process
branches of the facial nerve as it traverses the facial canal
Within the temporal bone Greater petrosal nerve Chorda tympani nerve nerve to the stapedius Sensory branch of CN VUU (joins CN -X)
greater petrosal nerve associated with?
maxillary nerve - giving fibers (GVE)
chorda tympani nerve associated with?
mandibular nerve - giving fibers of GVE and SA from CN VII
Branches of the facial nerve after exiting the skull via the styloimastoid foramen
Posterior auricular nerve Digastric Branch Stylohyoid branch Temporal Branch Zygomatic Branch Buccal Branch (of CN VII) Mandibular /marginal mandibular branch Cervical branch
sensory ganglion associated with CN VII
Geniculate ganglion
greater petrosal nerve
origin and course
emerges from the geniuclate ganglion and travels within the temporal bone before passing into the middle cranial fossa via the hiatus for the greater petrosal nerve –> then towards the opening of the carotid canal –> where it UNITES WITH THE DEEP PETROSAL NERVE (SYMPATHETIC FIBERS coming off of the internal carotid artery and its plexus) to form the nerve of the pterygoid canal
nerve of the pterygoid canal
merging of the greater petrosal nerve and the deep petrosal nerve and travels in the pterygoid canal
this nerve will travel along/within the cartilage that fills foramen lacerum –> traverse the pterygoid canal (vidian canal) –> enter the PPG
chorda tympani nerve
origin
course
has to pass posterior to anterior
emerges from CN VII within the facial canal - travels superior and anterior before passing toward the tympanic cavity via POSTERIOR CANALICULUS FOR THE CHORDA TYMPANI –> then proceeds anteriorly to travel within the layers of the tympanic membrane and acorss the handle of the malleus–> re-enters the temporal bone via the ANTERIOR CANALOCULUS for the chorda tympani –> leaves the temporal bone via the pterygotympanic fissure into the infratemporal fossa
importance of pterygotympanic fissure
at tympanic plate of temporal bone and where the chorda tympani will go from the temporal bone and into the infratemporal fossa where it WILL JOIN WITH THE LINGUAL NERVE
position of chorda tympani in the infratemporal fossa
it is positioned MEDIAL TO THE SPINE OF SPHENOID (away from the TMJ) – and courses anteriorly to join the lingual nerve and contributing GVE, SA, and GVA fibers
temporofacial trunk
trunk off of CN VII AFTER EXITING SKULL via the stylomastoid foramen
this trunk typically gives rise to temporal, zygomatic and buccal branches of CN-VII
Cervicofacial trunk
trunk off of CN VII AFTER EXITING SKULL via the stylomastoid foramen
this trunk typically gives rise to the buccal, marginal madnibular and cervical branches
what gives rise to the parotid plexus?
branches from the temporofacial and cervicofacial trunks
Distribution of temporal branch
muscle in morehead, temporal, supraorbital regions, anterior and posterior auricular muscles
SVE
sensory ganglion associated with CN VII
Geniculate ganglion
so we have pseudounipolar neurons
where does the the chorda tympani nerve end up
in the infratemporal fossa - gets there by taking a posterior to anterior route
exits bone - tympanic cavity - re enters bone and then exits again through the petrotympanic fissure to reach the ITF
what fiber types do the chorda tympani contribute when it enters the infratemporal fossa?
GVE, SA,
fiber type of the branches from CN VII after traversing the stylomastoid foramen
SVE
- the nerve to the stapedius also had this as well
distribution of zygomatic branch and fiber type
SVE fibers from CN VII
muscles at angle of the eye, infraorbital region, upper nasal region
distribution of buccan branch and fiber
SVE from CN VII
muscles in lower nasal and upper lip region
distribution of marginal mandibular branch and fiber type
SVE from CN VII
going to the muscles in lower lip and chin
Cervical branch distribution and fiber type
SVE from CN VII
supply the platysma
Digastric branch
innervates - SVE of the posterior digastric
Stylohyoid branch
stylohyoid
Posterior auricualr nerve
branches and distribution
Gives rise to auricalar branch and occipital branch
both SVE from CN VII
Auricaular - posterior auricular muscle
Occipital branch - occipital belly of the occipitofrontalis muscle
what type of ganglion is the PPG?
PARAYMPATHETIC
-so the nerve of the pterygoid canal WILL SYNAPSE HERE - caryying the GVE fibers from CN VII - connecting with V2
resident fibers of CN V
GSA and SVE
where are the GVE sympathetic fibers from
the superior cervical ganglion
NO synapse in the PPG because these are ALREADY POSTGANGLIONIC
what type of ganglion is the submandibular
parasympathetic
what provides the parasympathetic outflow from the PPG
CN VII - specifically the nerve of the ptergoid canal synapses and then is distributed throughout V2
T/F you will never see a sympathetic fiber leave the brainstem in this region
TRUE - the postganglionic fibers leave the superior cervical ganglion
so the sympathetic fibers (GVE) that are distributed within this nerve are postganglionic
fiber types in the greater petrosal nerve?
Taste (SA) and Parasympathetic (GVE fibers)
fiber types in the nerve of the pterygoid canal
taste (SA), parasympathetic
and sympathetic
