Facial Nerve

Question 1

anatomy

Answer 1

PMJ: motor roor and superior salivatory nucleus (nervus intermedius); start of LMN

IAM and facial canal:
geniculate ganglion (greater petrosal nerve, nervus intermedius)
nerve to stapedius and chorda tympani

medial wall of middle ear: 2nd genu (posteriorly), stylomastoid foramen
posterior auricular branch

parotid gland: between supf/deep lobes
temporal, zygomatic, buccal, mandibular, cervical nerves

Question 2

branches and functions

Answer 2

greater petrosal: lacrimal, submandibular, sublingual secretomotor
nervus intermedius: sensory + PANS
nerve to spapedius: motor; loud reflex
chorda tympani: anterior 2/3 tongue taste
posterior auricular: somatic skin
somatic motor branches (TZBMC)

functions:
PANS secretomotor: subM, subL, lacrimal, nasal cavity, palate, pharynx glands
special sensory: taste
somatic sensory: post. ear, EAM, TM, NP, palate, mouth (referred otalgia, RHS)
somatic motor: facial mm, posterior digastric, stapedius, stylohyoid

Question 3

testing

Answer 3

taste
stapedius reflex
facial muscles: eyebrows (T), close eyes (Z), puff cheeks (B), smile with teeth (M), bear teeth/shaving (C)

• UMN: contralateral lower face, forehead spared
• LMN: full ipsilateral face

Question 4

history questions

Answer 4

onset: congenital, acute, slow, progressive
severity, forehead, complete/incomplete
associated Sx:
-otological: deafness, otorrhoea, otalgia, vertigo, tinnitus
-neurological: CAV, MS, GBS
-parotid: massess, pain, food/eating
-systemic: infection, sarcoid
triggers: trauma, URTI, viral contacts/infection, parotid swelling, surgery

Question 5

palsy management

Answer 5

identify cause: neuro, ear, parotid, oral examination, Systems r/v

manage paralysis: steroids and aciclovir

eye care: exposure keratits, ulceration, blindness
artificial tears, ?surgery (slings for mm position), ?closure (stitches)

Question 6

complications

Answer 6

exposure keratitis, ulceration, blindness
taste loss
permanent facial weakness/paralysis
hyperacusis, noise-induced damage, perforation

Question 7

Bell’s palsy (80% of facial palsies)

Answer 7

viral infection; sudden onset, post-URTI; bony canal swelling
LMN lesion: total ipsilateral facial weakness; no CNS or ear pathology; can affect skin/glands/taste

Question 8

Parotid disease

Answer 8

lower level lesion: facial mm only (after SM foramen)
LMN; may only affect some branches; can start as weakness and progress

?cause: tumour (pleomorphic adenoma, SCC, AC), surgery

Question 9

Skull base pathology

Answer 9

cerebellopontine angle: total LMN palsy - taste, skin, glands, face
CN VIII (At CPA): HL and tinnitus; also CN IX-XII

trauma history, #BOS (Battle’s), transverse fracture (10-20% of fractures)

Question 10

facial nerve paralysis

Answer 10

UMN lesion - cortex/pons; contralateral lower facial weakness; skin/taste/glands

causes: TIA/CVA, intracranial tumours, neurological (UMN) disease

Question 11

Ramsay-Hunt syndrome

Answer 11

reactivated HSV
vesicles in ear/palate, facial pasly, pain; may have vertigo and HL

Rx: asap aciclovir (only effective if early)

Question 12

middle ear pathology

Answer 12

facial nerve on medial wall; risk during surgery, infection, trauma

high risk: malignant OE and cholesteatoma

Question 13

palsy severity

Answer 13

I= normal
II = slight (close inspection)
III = obvious but not disfigured
IV = reduced movement and eye closure affected
V = asymmetry at rest, no motion
VI = no movement

Question 14

palsy aetiology

Answer 14

cortical: neuro, TIA/CVA, intracranial tumours
surgery (mastoid, parotid, middle ear)
tumours: CPA, parotid, middle/external ear, petrous bone
neurological disease e.g. MS
viral inflammation/irritation

Question 15

Bells Palsy Rx

Answer 15

high dose PO steroids if