5th, 7th, 8th

5^th cranial nerve- Trigeminal

Sensory: touch, pain + temp

Motor: muscle of mastication

Divisions:

V1: ophthalmic: forehead, upper eyelid, cornea + nose tip

V2: maxillary: cheeck, lower eyelid + upper lid

V3: mandibular: sensory: lower lip, chin, anterior tongue – motor: mastication muscle

5th - clinical ass

Clinical assessment

-          Sensory: cotton wisp, foreheadv1, check v2, chin v3

-          Sharp object: pain

-          Cold fork: temp

Motor: palpitate jaw muscle

-          Test jaw reflex

Corneal reflex: touch cornea- blink via CNV: sensory + CNIII – motor

5th - dysfunction

Dysfunction

-          Trigeminal neuralgia: severe sudden facial pain

-          Herpes zoster: painful rash: shingles

-          Loss of sensation in face

-          Infraorbital anaesthesia

7^th CN: VII facial nerve

Motor: facial expression

Sensory: taste 2/3 of tongue

Parasympathetic: lacrimal tears + salivary glands

Pathway: N in pons – loop around CNVI

-          Emerge w CNVII at IAM – through facial canal via stylomastoid foramen

7th clinical ass

Clinical assessment

-          Ask pts: raise eyebrows, frown, close eyes tightly, smile + puff cheeks

-          Taste test

-          Stapedius test

7th dysfunction

Dysfunction

-          Bell’s palsy sudden, unlit, facial paralysis 1 side of face

-          Ramsay Hunts: facial paralysis + ear vesicle – zoster

Other conditions

-          Crocodile tears

-          Hemifacial spams

-          Facial myokymia

-          Blepharism

8^th CN: VIII – vestibulocochlear N  

Cochlear: hearing

Vestibular: balance + special orientation

Pathway:

-          Enter IAM

-          Cochlear F end in organ of Corti – relay to cochlear nuclei

-          Vestibular F ↑ from vestibular ganglion – project to semicircular canals

8th clinical ass

Clinical assessment

- Hearing: whisper test

- Rinne – air vs bone + weber

- Vestibular: Dolls head maneuverer

o Looks for nystagmus

8th dysfunction

Dysfunction

-          Hearing loss, vertigo, motion sickness, tinnitus, nystagmus

Acoustic neuroma

-          Beginning tumour at IAM

-          Affects CNVII + CNVII if large

-          Hearing loss, imbalance, facial weakness