neuroCranialNerves

• I: olfactory nerve
• II: optic nerve
• III: ocular motor nerve
• IV: trochlear nerve
• V: trigeminal nerve
• VI: abducens nerve
• VII: facial nerve
• VIII: vestibulocochlear nerve
• IX: glossopharingeal nerve
• X: vegus nerve
• XI: accessory nerve
• XII: hypoglossal nerve

• (CN I)
• transmit signals from nasal cavity

• presenting non-noxious odorants separately to each nostril
• person occludes one nostril and is asked if smells something (after visual inspection for obstructions)

bc they produce reactions mediated by trigeminal nerve that signals injury

• anosmia
• can be uni or bilateral

olfactory agnosia

info on visual acuity (central vision) and visual fields (peripheral vision)

• by testing visual acuity and visual fields separately
• impt ot inspec the eyes and eyelids for assymetrics (ptosis or exophthalmos)

• in each eye separately
• pt covers one eye and reads letters or numbers 20ft away and on pocket sized card held 14" away
• normal vision is 20/20 if person can read what is expected at 20 ft

can be myopia or hypertropia

• confrontation test
• pt covers one eye and looks directly at examiners nose
• examiner presents a static visual stim to each of the four diagonal vis quadrants

scotoma, anopsia, and hemianopsia

• (CN III)
• levator palpebrae (lifts upper eyelid)
• regulates pupilary function and lens shape

• (CN IV)
• the superior oblique muscle of the eye

• (CN VI)
• lateral rectus muscle of the eye

• examines ocular motility
• starts w/ observation of the eye's axis when looking straight ahead at distant object

• heterotropia or starbismus
• can be comitant or noncomitant

• mixed nerve w/ 3 divisions: opthalmic, maxillary, and mandibular
• sensory innerv on face and eye
• motoric: muscles of mastication, mylohyoid, ant digastric, m. tensor tympani

• 1. use sharp or blunt pressure on forehead
• 2. use test tubes filled with warm/cold water
• 3. corneal reflex test (trigeminal sensory, facial motor)

two tubes of same temp are placed simultaneously in similiar locations on either side of the face -- discrepancies if the temp feels stronger on one side vs the other

• if opthalmic part damaged: no response seen in either eye after corna touchd by wisp of cotton
• if facial n. part damaged: no repsonse seen on the lesion side when touched
• blink response on the nonlesion side will be present regardless of which cornea is touched

pt asked to alternately bite hard and relax with mouth and teeth closed

pt asked to push the jaw forward w/ mouth slightly open (any deviation should be noted)

• push tongue against roof of mouth
• examiners palpates submandibular triangle

• (CN VII)
• mixed cranial nerve
• motor: muscles of facial expression, platysma, post digastric, stylohyoid, stapedius
• sensory: transmits taste from anterior 2/3 of tongue and general senstation from oropharyngeal mucosa and skin in external ear canal
• autonomic: lacrimal gland, submandibular and submaxillary salivary glands and nasal mucosa glands

• facial expression capability w/ attention to lower eyelids, nasolabila folds, and mouth corners
• -- wrinkle forhead w/ head straight and eyes looking up
• -- close eyes forcefully
• -- purse lips
• -- smile widely showing teeth

• eyebrow on invovled side may not rise and winkles appear on that side
• approximation of upper and lower eyelids will be incomplete and sclera below the iris wil be seen btwn the eyelids
• corner of the mouth on the involved side will not move laterally, smile is asymmetric

• ant 2/3 of tongue
• apply dilute solutions of glucose, NaCl, citric acid and quinine to either side of tongue separately
• pt points to the word indicating the taste

person may point to the word water when one of the test subjects is applied to tongue

• stylomastoid foramen as the nerve exits the skull
• paralysis of the facial muscles on ipsilateral side of the face (Bell's Palsy)

ageusia (absense of taste) in addition to weakness or paralysis of facial muscles

contralateral facial weakness only in mm of lower 1/2 of face

• (CN VIII)
• 1. cochlear: audition and hearing
• 2. vestibular: equilibrium, monitoring position and orientation of the head

• simple test: rubbing noise applied lateral to the ear
• -- further tests needed if pt performs poorly
• Rinne's test
• Weber's test

• used to test audition functionality of vestibulocochlear nerve place tuning fork against mastoid process, when tone no longer heard,
• the tuning fork is then brought to ext aud meatus and pt is asked if they hear a noise (normally it will be heard and for twice as long at
• the ext aud meatus)

• place the tuning fork on vertex of the skull or in center of forehead
• pt indicates on which side (if either) the tone is louder

• (prob with vestibulocochlear n)
• tone is louder in the normal ear (tone is lateralized to the good ear)

• (prob with vestibulocochlear n)
• tone is louder on the diseased side (tone is lateralized to the bad ear)

impulses from the receptors responding to rotational (semicircular canals) and linear (utricle and saccule) movements of the head

• simple tests performed as part of routine neurological exams
• -- alt touch nose and reach for examiners finger 3-4 times w/ eyes open and then eyes closed
• -- march in place w/ eyes open and closed
• careful function evaluated only when vestibular or cerebellar dysfunction is suspected

• problem with vestibulocochlear n.
• will drift away from the examiner's finger toward the side of the vestibular disease

will rotate to one side when eyes are closed

• (CN IX)
• mixed nerve
• innervaties stylopharingeal mm and parotid gland
• leave the skull through the jugular foramen and synapse w/ otic ganglion

visceral and somatic

• sensations from pharyngeal mucosa, taste from post 1/3 of tongue, impulses from baroreceptors in the carotid sinus
• terminates in nucleus solitarus

• little or no clinical importance
• tactile info from external ear canal

a dysfunction of the glossopharingeal nerve

• (CN X)
• mixed nerve
• sensory fibers: mostly transmitting info from thoracic and abdominal visceral structures, chemoreceptors of the carotid body, and taste receptors on epiglottis
• motor fibers: innerv mm of soft palate, pharyngeal constrictors, intrinsic/extrinsic mm of larynx
• parasympathetic innerv of abdominal smooth mm and glands

• observation of uvula and soft palate when pt says "ahhhh"
• gag reflex when touching lateral wall of pharynx wall

• deviation of uvula during phonation
• loss of gag reflex on involved side

• (CN XI)
• motor nerve
• C1-C4
• innervates SCM and traps - test mm strength and asymmetry of these muscle functions

• (CN XII)
• motor nerve
• innerve to intrinsic/extrinsic mm of tongue (most impt for tongue protrusion)

• observe tonge resting in mouth - mass and contour
• pt asked to protrude the tongue or push it into the cheek, tongue remains in midline

tongue will deviate towards the side of involvement