2nd half of CN lecture Flashcards
Is CN VII motor, sensory, or both?
Both
You know that CN VII mediates facial expression by motor to muscles, but what 2 parasympathetic actions does it carry?
Salivation and lacrimation
What are the two main areas of sensory for CN VII?
Behind the ear/ concha and the anterior 2/3 of the tongue
How many branches are there of the facial nerve and what are their names?
- Temporal, Zygomatic, Buccal, Mandibular, Cervical To Zanzibar By Motor Car
What are the 3 ganglions associated with CN VII? (2 in one
Geniculate Ganglion - Pterygopalatine ganglion - Lacrimal gland Geniculate Ganglion - Submandibular ganglion - Submandibular/ sublingual glands
What is the pathway of facial motor nerves?
Facial motor nucleus - VII nerve - IAC - Facial Canal - Stylomastoid Foramen - passes through the parotid gland - muscles
True/False: CN VII has bilateral innervation the for whole face.
False. Bilateral is only the forehead. Stroke (UMN) will have forehead sparing, Bell’s Palsy (LMN) won’t.
Describe the special sensory components
Taste from Lingual N to Chorda Tympani to Facial N
CN VII is involved in the corneal blink reflex. Efferent or afferent?
Efferent (exit) Afferent is V1
If you have abnormal taste on the anterior 2/3 of the tongue, where would the lesion be?
Lingual N or Chorda Tympani
Hyperacusis (sensitivity to certain frequencies/ volume) can happen with paralysis of ______ muscle
Stapedius
Bell’s Palsy is a LMN lesion of CN VII. What would you expect to see?
Paralysis and possibly atrophy of the muscles of facial expression Uncontrolled tearing Lips cannot be held together and food will spill out on affected side Loss of the efferent limb of the CORNEAL REFLEX - cannot close eye
It matters if you cut above or below where the Chorda tympani joins the lingual nerve. Why?
Cut Lingual N ABOVE where chorda tympani joins spares CN VII and only cuts CN V.
You would spare taste, but lose general sensation from anterior 2/3
A Schwannoma can effect what 2 nerves?
CN VII and CN VIII
Vestibulocochlear Nerve VIII exits the brain stem at the ____________ _______ and enters _____ _____ ____into the _______ ____
Cerebellopontine Angle Internal Auditory Canal Petrous Bone
Cn VIII regulates compensatory eye movements via what?
Think about where CN III, IV, and VI go.
Medial Longitudinal Fasciculus
How would you test CN VII?
–Observe nystagmus during EOM Test
–Romberg Test: Patient falls to side of vestibular hypofunction
•Also seen in dorsal column disease - Lues
–Caloric Testing
–Coordination Examinations
Name 3 lesions of CN VIII
–Acoustic Neuroma and aneurysms
–Meningiomas
–MS
Describe bone and air conduction. Where and how are those waves transmitted? Which do you expect to be louder?
- Conductive hearing loss: Disorder of the external and/or middle ear impairing conduction of sound to the inner ear.
- Sensorineural hearing loss: Disorder of the inner ear, cochlear nerve, or its central connections impairing transmission of nerve impulses to the brain.
- Air conduction describes the normal hearing pathway from the external ear to the junction of the middle and inner ear.
- Bone conduction bypasses the external and middle ear. The bones of the skull vibrate and stimulate the cochlea directly.
- Normally, air conduction is more sensitive than bone conduction
What are the two tests to study for bone and air conduction?
Weber and Rinne
What is the area where the ossicles are held called?
Vestibule (antechamber)
If you get a tumor on CN VIII what 3 symptoms would you have?
Deafness, Vertifo, Tinnitis