Muscles of facial expression and Stapedius are innervated by what special CN7 subgroup? a. General Somatic Afferent b. General Visceral Efferent c. Special Visceral Afferent d. Special Visceral Efferent
d. Special Visceral Efferent (Facial n./ motor nucleus
Sensory cutaneous, External auditory meatus and the back of the ear are innervated by what special CN7 subgroup? a. General Somatic Afferent b. General Visceral Efferent c. Special Visceral Afferent d. Special Visceral Efferent
a. General Somatic afferent (interm n.)
Taste of anterior 2/3 of the tongue (chorda tympani) is innervated by what special CN7 subgroup? a. General Somatic Afferent b. General Visceral Efferent c. Special Visceral Afferent d. Special Visceral Efferent
c. Special Visceral Afferent (interm n./solitary nucleus)
What innervates the Parasympathetic system of CN7 subtype? a. General Somatic Afferent b. General Visceral Efferent c. Special Visceral Afferent d. Special Visceral Efferent
b. General Visceral Efferent (interm n./salvatory nucleus)
What are the 5 branches of he visceral efferent or terminal motor branches of the facial nerve?
What type of pathway has the following characteristics:
-incased in bone (either the fallopian or facial canal)
- Have salivatory sensory
-Exit cranial cavity via internal auditory meatus
- Combined version of CN7 through tortuous facial canal
-Geniculate Ganglion is involved
-Exit occurs via stylomastoid foramen?
The extracranial pathway is located, distal or proximal, to the stylomastoid foramen?
True or False. Since the extracranial pathway, motor root, passes through the parotid gland, does it also innervate it too?
What are two major structures that the CN7 intermediate nerve will emerge from?
Facial motor root and CN8
What are the two major functions of Visceral efferent of CN7 intermediate nerve?
Parasympathetic regulation of lacrimal and salivary system
What are the two major functions of Visceral afferent of CN7 intermediate nerve?
Anterior toungue taste and Somatsensory distribution
What can be affected by lesions along the CN7 pathway?
-Facial muscles of expression + stapedius
What is the clinical work up protocol for Facial Paralysis?
History (viral prodome)
Ear (mass or vesicles --> may have ear pain due to external canal
Additional CN assessment (CN5,6,8 --> in the area of CN7)
Taste: Bitter or sweet anterior 2/3 tongue affected side
Facial motor weakness
What anatomical areas or structures are you observing when examing superior group?
Eyebrows, Forehead, Scalp, and Ears
What anatomical areas or structures are you observing when examing inferior group?
Smiling, lips, note flattening of nasolabial fold
What anatomical areas or structures are you observing when examing intermediate group?
tightly squeezing eyelids and ectropion
Where the numbers are listed, name the type lesion that can occur?
4.Isolated ipsilateral tear deficiency
5. and 6. Bell’s palsy (total facial palsy)
7. Partial facial palsy per affected distal branches
Contralateral “voluntary” paralysis of lower 2/3 of face means that there is a supranuclear lesion. What pathway has been affected?
a) Preserved frontalis volitional function because of “dual supply” to each CN VII motor nucleus from R and L corticobulbar tract.
b)Ipsilateral mostly innervates upper facial m.
c) Lesser preservation of o.o. function
d) Preserved taste, lacrimation, salivation
e) Rarely occur in isolation
f) May have ipsilateral hemiparesis
What type of pathway will cause dissociation of voluntary and mimetic (emotional) response?
What are the 4 possible etiologies of a Supranuclear lesion?
a. Vascular (stroke)
-Look for VI n palsy (uni- or bi-lateral) resulting from elevated ICP
With the following signs, what type of lesion is this?
a. Upper and lower facial paralysis
b. Preserved taste & secretory
c. Ipsilateral VI n involved & other CN likely
d. May have contralateral hemiparesis of extremities
What is the most common etiology for Nuclear lesion ?
most common – basilar and vertebral a. branches
What are the signs of Ramsey-Hunt?
Loss of taste, secretory
Hearing loss, tinnitus
Where does the lesion occur with Cerebellopontine Angle?
Pre geniculate - before it exits the ear
What are the signs of cerebellopontine angle?
-Total ipsilateral facial weakness
-Facial pain and twitching
w/absent tearing, hyperacusis, loss of taste
-Can associate w/ CN V, VI, VIII, Horner’s, gaze palsy, nystagmus, papilledema, cerebellar dysfunction
The following signs display what type of lesion?
-Complete ipsilateral facial paralysis, hyperacusis, impaired secretory functions
-Definite loss of taste anterior 2/3
-Impaired ipsilateral lacrimation (measure w/ Schirmer’s)
-Knocks out all visceral afferent and parasympathetic
-Complete lesion here produces permanent loss of taste and sensory
-Preganglionic fibers can regenerate aberrantly
Lesion proximal to geniculate ganglion
With the following signs, where has this lesion occurred?
-Complete ipsilateral facial paralysis PLUS
-Possible impaired salivary function
-Often ipsilateral loss of taste anterior 2/3
-Special visceral afferents
Lesion distal to geniculate g. & pre stylomastoid foramen
The most common cause of facial paralysis is?
What type of lesion is this?
What are the peipheral lesions of Bell's Palsy?
Complete ipsilateral VII weakness
No other associated CNS deficits
Epiphora vs dry?
Droopy lid vs widened fissure?
Rarely: pain in ear canal
Progresses over 2-10 days
Absent corneal reflex but intact sensation
May have widened palpebral fissures