CN7- Facial nerve Flashcards
what are the two components of the facial nerve
Facial n proper and Intermediate
what are the components of the facial n proper
visceral m- muscles of facial ex, stapedius, stylohyoid
general somatosensory- auricle
what are the components of the facial n intermediate
Has parasympathetic components
Greater petrosal- to pterygopalantine ganglion
Lesser petrosal- to submandibular ganglion
General passage of the facial nerve
will run into the internal acoustic meatus will pass over cochlea and then make a 90 degree turn (genu) to go cuadally and exit out the stylomastoid foramen
what branches does the facial nerve give before it exits out of the stylomastoid foramen in middle ear
stapedius m
Path of greater petrosal n
enters interal auditory meatus runs through greater petrosal foramen and foramen lacerum + pterygoid callan to the ptergopalantine fossa
path of lesser petrosal n
enters internal auditory meatus and exit thru petrotympanic fissure in middle ear
what path does CNV use
greater petrosal
where does greater petrosal n synapse and lead to
Pterygopalantine ganglion to lacrimal, nasal mucosal and oral mucosal glands
where does lesser petrosal n synapse and lead to
submandibular ganglion out side petrotympanic fissure
to submandibular and sublingual salvary glands
where is the internal carotid artery found and what surronds it
surrounded by parasympathetic postganglionic plexus that connects to the great persal n via deep persoal
where does sensory from the ant 2/3 of the tongue and taste from soft palate run with
ant tongue with lesser petrosal
soft palate with greater petrosal
both synapse at genicular ganglion
what does the motor root of the facial nerve run thru after it exits out of the stylomastoid process
enters into the parotid gland forming parotid nerve plexus (does not innervate it tho)- the branches will then emerge under the gland and go to its targets
what is paratiditis and what can it cause
viral infection causes swelling and pain which can in turn compress CN7
main branches of facial n from top to bottom
temporal zygomatic buccal branches Marginal mandibular cervical
what is bells palsy generally due to and generally affects
lower motor neuron lesion of brachiomotor component which causes same side paralysis of facial m (drooping on one side
what are the 3 sites that the nerve can be affected in bells palsy
A- motor nuclei
B- Internal auditory meatus
C- Stylomastoid foramen
When could sound be distorted in bells palsy
if nerve was affected at motor nucli or internal auditory meatus (but NOT stylomastoid foramen)
What is crocodile tears syndrome
during recovery from bells palsy, regenerating salviary fibres in the facial n become misdirected and innervate the lacrimal gland
as result stim such as smell may produce simultaneous flow of tears on side of bells palsy
branches of the aoritic arch
LCCA
LSA
Brachiocephalic trunk-> right subclavian and RCCA
what does the common carotid artieries give rise too and location of them
splits into ext and int carotic artery (ext is located medially @ bifurcation then at base of skull it will switch back)
which carotid artery doesnt have any branches in the neck region
internal ( thus if u see branches right at the bifurcation u know it has to be external)
what are the 2 terminal branches of the ext carotid
maxillary (which splits off at lvl of mandible)
Superficial temporal
where is the facial artery pulpasion most palpable
where it crosses the mandibular body
where does the internal carotid vein go and what drains into it
descends thru jugular foramen (deep to scm) eventually joins sup vena cava
-all blood from dural sinus, facial vein, opthalmic vein
what drains into the external carotid and where does it go
gets bood from post auricular and drains in subclavian v
drainage of lymph from head/neck
superficial lymph ring drains into deep cervical lymph nodes along internal jugular vein which eventually drain into that vein
how do you test the buccinators and orbiularis oris
tested by asking the pt to press lips firmly together or to blow cheeks
how to test taste buds
add taste to either side of tougue and see if different
how to test lacrimal and salvitory gland function
direct questioning about pressence of dry eyes/dry mouth
how to test function of stapedius
clapping beside each ear to see change one to the other
if sound is loud then stapedius likely affected
