NIHD - Week 4: Cranial Nerves 5, 7, 8, 9, 10, 11, 12, Boards and Beyond Cranial Nerves, First Aid pg. 502

Bell's Palsy: - Idiopathic mononeuropathy of CN ____ - Facial Paralysis - Thought to be due to HSV-1 induced nerve damage

Bell's Palsy: - Idiopathic mononeuropathy of CN *VII* - Facial Paralysis - Thought to be due to HSV-1 induced nerve damage

A patient presents with weakness of the right side of her face, with a droopy smile - loss of taste from tip of her tongue Loss of taste = chorda tympani affected. For a single lesion to explain both facial weakness (motor branches of CN VII) AND loss of taste (chorda tympani) it must occurred **__________ to the branching of chorda tympani, such as within the _______________ bone (LESION AT GENICULATE GANGLION)

A patient presents with weakness of the right side of her face, with a droopy smile - loss of taste from tip of her tongue Loss of taste = chorda tympani affected. For a single lesion to explain both facial weakness (motor branches of CN VII) AND loss of taste (chorda tympani) it must occurred **PROXIMAL* to the branching of chorda tympani, such as within the *temporal* bone (LESION AT GENICULATE GANGLION)

A patient presents with weakness of the right side of her face, with a droopy smile. - taste is normal Taste from the anterior 2/3 of the tongue is supplied by ________ ___________, a branch of CN VII. If taste is preserved, then the chorda tympani is intact, lesion is ***__________ to where chorda tympani branches off (aka somewhere distal to the sylomastoid foramen) SEE LESION (A) on diagram

A patient presents with weakness of the right side of her face, with a droopy smile. - taste is normal Taste from the anterior 2/3 of the tongue is supplied by *chorda tympania*, a branch of CN VII. If taste is preserved, then the chorda tympani is intact, lesion is *distal* to where chorda tympani branches off (aka somewhere distal to the sylomastoid foramen) SEE LESION (A) on diagram

A patient presents with weakness of the right side of her face, with a droopy smile. Facial weakness is caused by damage to CN VII affecting the branches innervating muscles of facial expression, resulting in _________ __________

A patient presents with weakness of the right side of her face, with a droopy smile. Facial weakness is caused by damage to CN VII affecting the branches innervating muscles of facial expression, resulting in *Bell's Palsy*

Accessory (XI): - motor - turning head - shoulder shrugging a. Sternocleidomastoid b. Trapezius Palsy: - difficulty turning head toward normal side (SCM) - shoulder drop (_____________ side)

Accessory (XI): - motor - turning head - shoulder shrugging a. Sternocleidomastoid b. Trapezius Palsy: - difficulty turning head toward normal side (SCM) - shoulder drop (*Affected* side)

Cranial Nerve IX: Glossopharyngeal Function GVA from carotid body and sinus, ___________ 1/3 third of tongue, pharynx, middle ear SVA for taste posterior 1/3 of tongue ***GVE to the parotid gland ***GSE to the ________________ muscle

Cranial Nerve IX: Glossopharyngeal Function GVA from carotid body and sinus, **posterior* 1/3 third of tongue, pharynx, middle ear SVA for taste posterior 1/3 of tongue ***GVE to the parotid gland GSE to the *stylopharyngeus* muscle

Cranial Nerve V: Trigeminal - Emerges from *brainstem*; as a large sensory root and a smaller motor root. - both roots together cross the temporal bone (petrous portion) to enter the middle cranial fossa. - sensory ganglion sits in a shallow depression, the trigeminal cave (____________'s cave)

Cranial Nerve V: Trigeminal - Emerges from *brainstem*; as a large sensory root and a smaller motor root. - both roots together cross the temporal bone (petrous portion) to enter the middle cranial fossa. - sensory ganglion sits in a shallow depression, the trigeminal cave (*Meckle*'s cave)

Cranial Nerve V: Trigeminal V1: ______________ Divison - Sensory V2: Maxillary Division - Sensory V3: Mandibular Division - Sensory and Motor

Cranial Nerve V: Trigeminal V1: *Opthalmic* Divison - Sensory V2: Maxillary Division - Sensory V3: Mandibular Division - Sensory and Motor

Cranial Nerve VII: _________ _________ n. Function: GVE [preganglionic parasympathetics + SVA (taste)] Course: joins the lingual nerve of CN V3 to convey taste from anterior 2/3rds of tongue and soft palate.

Cranial Nerve VII: *Chorda tympani* n. Function: GVE [preganglionic parasympathetics + SVA (taste)] Course: joins the lingual nerve of CN V3 to convey taste from anterior 2/3rds of tongue and soft palate.

Cranial Nerve VII: Facial ****************Course cont- Traverses posterior cranial fossa -> entering the __________ acoustic meatus -> auditory canal of petrous _____________ bone (together with CN VIII). nerve fascicle takes a turn (_____ - red) posteriorly and inferiorly in temporal bone. travels via __________ canal (blue) medial to middle ear 1. Internal Acoustic Meatus 2. Auditory Canal w/ CN VIII 3. Take a turn at Genu (red) 4. Travels via facial canal medial to middle ear (blue) 5. Exits at Stylomastoid Foramen

Cranial Nerve VII: Facial ****************Course cont- Traverses posterior cranial fossa -> entering the *internal* acoustic meatus -> auditory canal of petrous *temporal* bone (together with CN VIII). nerve fascicle takes a turn (*genu*- red) posteriorly and inferiorly in temporal bone. travels via *facial* canal (blue) medial to middle ear 1. Internal Acoustic Meatus 2. Auditory Canal w/ CN VIII 3. Take a turn at Genu (red) 4. Travels via facial canal medial to middle ear (blue) 5. Exits at Stylomastoid Foramen

Cranial Nerve VII: Facial Course cont- - exits skull at ______________ foramen

Cranial Nerve VII: Facial Course cont- - exits skull at *stylomastoid* foramen

Cranial Nerve VII: Facial Function overview: GSA innervation from external acoustic meatus GSE to muscles of facial expression, stapedius, posterior belly of diagastric SVA (taste) from ____________ 2/3 of tongue GVE to submandibuar/sublingual/lacrimal glands - ALL ___________ glands, except parotid stylohyoid. Course: ********nucleus located in caudal pons*****; fascicles of facial nerve loops around abducens nucleus, forming facial colliculus (floor of 4th ventricle) --> (exits) at the cerebellopontine angle. QUIZ: infarcts affecting the dorsal pons at the level of the abducens nucleus can also affect the facial nerve, producing an ipsilateral facial palsy together with a lateral rectus palsy.

Cranial Nerve VII: Facial Function overview: GSA innervation from external acoustic meatus GSE to muscles of facial expression, stapedius, posterior belly of diagastric SVA (taste) from *anterior* 2/3 of tongue GVE to submandibuar/sublingual/lacrimal glands - ALL *salivary* glands, except parotid stylohyoid. Course: nucleus located in caudal pons; fascicles of facial nerve loops around abducens nucleus, forming facial colliculus (floor of 4th ventricle) --> (exits) at the cerebellopontine angle. QUIZ: infarcts affecting the dorsal pons at the level of the abducens nucleus can also affect the facial nerve, producing an ipsilateral facial palsy together with a lateral rectus palsy.

Cranial Nerve XII: Hypoglossal Corticobulbar input to the Hypoglossal Nucleus is primarily crossed. Thus, following an _____ lesion, the tongue will deviate to the side contralateral to the lesion. - _______ = tongue to SAME SIDE OF LESION

Cranial Nerve XII: Hypoglossal Corticobulbar input to the Hypoglossal Nucleus is primarily crossed. Thus, following an *UMN* lesion, the tongue will deviate to the side contralateral to the lesion. - *LMN* = tongue to SAME SIDE OF LESION

Cranial Nerves with visceral afferent fibers are limited to cranial nerves the convey information associated with olfaction and taste: CN's I, VII, IX, X IX and X have ___________________

Cranial Nerves with visceral afferent fibers are limited to cranial nerves the convey information associated with olfaction and taste: CN's I, VII, IX, X IX and X have *chemoreceptors*

Facial (VII) damage: - Lower Facial Droop: a. UMN damage (MCA stroke) Upper face ______ (Dual supply) Lower face affected b. LMN damage Whole half of face affected

Facial (VII) damage: - Lower Facial Droop: a. UMN damage (MCA stroke) Upper face *intact* (Dual supply) Lower face affected b. LMN damage Whole half of face affected

Facial (VII) nerve palsy: - Loss of corneal reflex (motor part) - Loss of taste ____________ 2/3 tongue - Hyperacusis (stappedius paralysis)- cannot tolerate sounds

Facial (VII) nerve palsy: - Loss of corneal reflex (motor part) - Loss of taste *anterior* 2/3 tongue - Hyperacusis (stappedius paralysis)-cannot tolerate sounds

Facial (VII): - Nucleus in ______ - Motor, sensory - Muscles of facial expression - Taste (Anterior *2*/3), salivation, lacrimation - Motor: Facial movement, stapedius muscle, eyelid closing - *Dual* ______ innervation

Facial (VII): - Nucleus in pons - Motor, sensory - Muscles of facial expression - Taste (Anterior *2*/3), salivation, lacrimation - Motor: Facial movement, stapedius muscle, eyelid closing - Dual *UMN* innervation

Facial Nerve LMN lesion (BELL's PALSY): First Aid Potential Causes: Vascular insufficiency (Basilar, AICA) Extreme Cold Trauma to the side of the face Surgical intervention of the parotid gland _________ ear infection/Labyrinthine a. (VII/VIII) __________ in the IVth ventricle (VI/VII) Cerebellopontine tumor (acoustic neuroma) Paralysis of ________ and lower face on affected side ******Muscle atrophy Loss of corneal (blink) reflex Loss of taste from anterior 2/3 of tongue Hyperacusis (___________) - debilitating hearing disorder Difficulty shaving due to loss of input to platysma Patient can't whistle or hold food in mouth Loss of _____________ and lacrimation Destruction of facial nucleus or CN VII anywhere along its course ____________ paralysis of upper and lower muscles of facial expression A , hyperacusis, loss of taste sensation to anterior tongue. When idiopathic (most common), facial nerve palsy is called Bell palsy. May also be caused by Lyme disease, herpes simplex, herpes zoster (Ramsay Hunt syndrome), sarcoidosis, tumors (eg, parotid gland), diabetes mellitus. Treatment is corticosteroids, acyclovir. Most patients gradually recover function.

Facial Nerve LMN lesion (BELL's PALSY): Potential Causes: Vascular insufficiency (Basilar, AICA) Extreme Cold Trauma to the side of the face Surgical intervention of the parotid gland *Middle* ear infection/Labyrinthine a. (VII/VIII) *Tumor* in the IVth ventricle (VI/VII) Cerebellopontine tumor (acoustic neuroma) Paralysis of *upper* and lower face on AFFECTED side ******Muscle atrophy Loss of corneal (blink) reflex Loss of taste from anterior 2/3 of tongue Hyperacusis (*stapedius*) - debilitating hearing disorder Difficulty shaving due to loss of input to platysma Patient can't whistle or hold food in mouth Loss of *salivation* and lacrimation Destruction of facial nucleus or CN VII anywhere along its course *ipsilateral* paralysis of upper and lower muscles of facial expression A , hyperacusis, loss of taste sensation to anterior tongue. When idiopathic (most common), facial nerve palsy is called Bell palsy. May also be caused by Lyme disease, herpes simplex, herpes zoster (Ramsay Hunt syndrome), sarcoidosis, tumors (eg, parotid gland), diabetes mellitus. Treatment is corticosteroids, acyclovir. Most patients gradually recover function.

First Aid 502 + Notes Facial Nerve UMN lesion: CN VII Motor nucleus that provides innervation to the forehead is bilateral VS. Motor neurons that innervate muscle of lower face are CROSSED Paralysis of ______________ ______ face Patient can't whistle or hold food in mouth - ____ muscle atrophy Destruction of motor cortex or connection between motor cortex and facial nucleus in pons contralateral paralysis of lower muscles of facial expression. Forehead is spared due to its _____________ UMN innervation.

Facial Nerve UMN lesion: CN VII Motor nucleus that provides innervation to the forehead is bilateral VS. Motor neurons that innervate muscle of lower face are CROSSED Paralysis of *contralateral lower* face Patient can't whistle or hold food in mouth - *No* muscle atrophy Destruction of motor cortex or connection between motor cortex and facial nucleus in pons contralateral paralysis of lower muscles of facial expression. Forehead is spared due to its *bilateral* UMN innervation.

Facial nerve (extra-cranial distribution) Function: GSE fibers innervate muscles of facial expression. Temporal Zygomatic _________ Marginal mandibular ___________

Facial nerve (extra-cranial distribution) Function: GSE fibers innervate muscles of facial expression. Temporal Zygomatic *Buccal* Marginal mandibular *Cervical*

Geniculate Ganglion & Facial Canal - the *geniculate ganglion* lies in the ______ - contains primary sensory neurons for taste sensation and GSE (near external auditory meatus, auricle). While traversing the facial canal (petrous portion; temporal bone) three nerves branches are found . 1. Greater ____________ n. 2. Nerve to the ____________ 3. Chorda tympani n. Note: CN VII = longest interosseous course of any cranial nerve!

Geniculate Ganglion & Facial Canal - the geniculate ganglion lies in the *genu* - contains primary sensory neurons for taste sensation and GSE (near external auditory meatus, auricle). While traversing the facial canal** (petrous portion; temporal bone) three nerves branches are found . 1. Greater *petrosal* n. 2. Nerve to the *stapedius*** 3. Chorda tympani n. Note: CN VII = longest interosseous course of any cranial nerve!

Glossopharyngeal (IX) - Motor, sensory - Taste/sensation __________ 1/3 tongue - Swallowing - Salivation (________ ________) - Carotid body and sinus a. chemo and baroreceptors - stylopharyngeus (elevates _________)

Glossopharyngeal (IX) - Motor, sensory - Taste/sensation *posterior* 1/3 tongue - Swallowing - Salivation (*parotid gland*) - Carotid body and sinus a. chemo and baroreceptors - stylopharyngeus (elevates *pharynx*)

Glossopharyngeal (IX): - Palsy a. Loss of gag reflex b. Loss of taste posterior 1/3 tongue c. Loss of sensation upper ___________/tonsils - Hemodynamic effects a. Tricks body into thinking low BP b. Inc HR, vasoconstriction, inc BP

Glossopharyngeal (IX): - Palsy a. Loss of gag reflex b. Loss of taste posterior 1/3 tongue c. Loss of sensation upper *pharynx*/tonsils - Hemodynamic effects a. Tricks body into thinking low BP b. Inc HR, vasoconstriction, inc BP

Hypoglossal (XII) - Nucleus in ________ - Motor - Tongue Movement - Palsy: *****a. protrusion of tongue _____________ affected side

Hypoglossal (XII) - Nucleus in *medulla* - Motor - Tongue Movement - Palsy: a. protrusion of tongue *TOWARD* affected side

Infraorbital nerve: Terminal branch of the maxillary nerve - exits PT fossa --> enters the orbit via the inferior orbital fissure. - ½ way between orbital apex & rim --> enters infraorbital canal -BECOMES infraorbital nerve. - **the infraorbital nerve supplies sensory branches to the ________ eyelid, the side of the nose, and the ________ lip.

Infraorbital nerve: Terminal branch of the maxillary nerve - exits PT fossa --> enters the orbit via the inferior orbital fissure. - ½ way between orbital apex & rim --> enters infraorbital canal -BECOMES infraorbital nerve. - the infraorbital nerve supplies sensory branches to the *lower* eyelid, the side of the nose, and the *upper* lip.

Maxillary (CN V2) -> Foramen _______________ -> Pterygopalatine Fossa

Maxillary (CN V2) -> Foramen *Rotundum* -> Pterygopalatine Fossa

*M*esencephalic Nucleus: proprioceptive information from the _____ (*m*astication) Chief Sensory Nucleus: Touch/pressure, -> Face, anterior 2/3 tongue, teeth, oral/nasal cavities, cornea (_______ reflex) Nucleus of the spinal tract: *****All pain/temp from the _______***** *******Quiz: descends on spinal tract, synapses on 2nd order spinal nucleus

Mesencephalic Nucleus: proprioceptive information from the *jaw* (mastication) Chief Sensory Nucleus: Touch/pressure, -> Face, anterior 2/3 tongue, teeth, oral/nasal cavities, cornea (*blink* reflex) Nucleus of the spinal tract: All pain/temp from the *face* ******Quiz: descends on spinal tract, synapses on 2nd order spinal nucleus

Palatine Nerves (greater and lesser) - The greater and lesser palatine nerves descends from the Pterygopalatine ganglion via the greater palatine foramen --> (enter) palatine canal --> (exit) greater and lesser palatine foramen. - Innervation: greater palatine supplies the gingivae, mucosa and glands of _______ palate -communicates with the nasopalatine nerve. - Innervation: the lesser palatine nerve supplies the ________, tonsil and ______ palate.

Palatine Nerves (greater and lesser) - The greater and lesser palatine nerves descends from the Pterygopalatine ganglion via the greater palatine foramen --> (enter) palatine canal --> (exit) greater and lesser palatine foramen. - Innervation: greater palatine supplies the gingivae, mucosa and glands of *hard* palate -communicates with the nasopalatine nerve. - Innervation: the lesser palatine nerve supplies the *uvula*, tonsil and *soft* palate.

Recurrent Laryngeal Nerve: - Branch of ___________ - ____________ towards larynx/esophagus - Compression -> hoarseness - Dilated left atrium (mitral stenosis) - Aortic dissection

Recurrent Laryngeal Nerve: - Branch of *Vagus* - *Ascends* towards larynx/esophagus - Compression -> hoarseness - Dilated left atrium (mitral stenosis) - Aortic dissection

Trigeminal (CN V) Neuralgia: - Aetiology = most common is vascular ______________, lesion (_______) and some demyelinating disorders, such as MS. - Chief complaints: lancinating pain involving one-side of the face -often spontaneously "___________-like" pain that travels through the face in a matter of seconds - Common triggers (a.k.a stimulus) touching the face brushing teeth eating, drinking, chewing or talking water hitting the face feeling a slight wind sometimes nothing at all

Trigeminal (CN V) Neuralgia: - Aetiology = most common is vascular *compression*, lesion (*tumor*) and some demyelinating disorders, such as MS. - Chief complaints: lancinating pain involving one-side of the face -often spontaneously "*shock*-like" pain that travels through the face in a matter of seconds - Common triggers (a.k.a stimulus) touching the face brushing teeth eating, drinking, chewing or talking water hitting the face feeling a slight wind sometimes nothing at all

Trigeminal (V) - Palsy: a. Numb face ****b. Weak jaw-> __________ to affected side c. Trigeminal neuralgia: Recurrent, sudden sharp pains in half of face

Trigeminal (V) - Palsy: a. Numb face b. Weak jaw-> *deviates* to affected side c. Trigeminal neuralgia: Recurrent, sudden sharp pains in half of face

Trigeminal (V): - sensory and Motor - Key function: sensory (touch-pain-temp) to ________ - Largest cranial nerve - 3 Divisions: opthalmic, maxillary, mandibular (V1, V2, V3) - Muscles of _____________ (chewing)

Trigeminal (V): - sensory and Motor - Key function: sensory (touch-pain-temp) to *face* - Largest cranial nerve - 3 Divisions: opthalmic, maxillary, mandibular (V1, V2, V3) - Muscles of *mastication* (chewing)

Trigeminal Division -Mandibular V3: MOTOR Function GSE (motor) to 1. Muscle of mastification: - _____________ - Masseter - Medial/lateral ______________ Miscellaneous muscles Mylohyoid Digastric (anterior belly) Tensor veli palatini Tensor tympani

Trigeminal Division -Mandibular V3: MOTOR Function GSE (motor) to 1. Muscle of mastification** - *Temporalis* - Masseter** - Medial/lateral *pterygoids* Miscellaneous muscles Mylohyoid Digastric (anterior belly) Tensor veli palatini Tensor tympani

Trigeminal Division -Mandibular V3: SENSORY GSA (sensory) from Lower ________, lower _______, lower teeth and anterior 2/3rds of tongue (not taste), ****tympanic membrane (_________ _________), auditory meatus, upper ear, dura matter (posterior cranial fossa)

Trigeminal Division -Mandibular V3: SENSORY GSA from Lower *face*, lower *lip*, lower teeth and anterior 2/3rds of tongue (not taste), tympanic membrane (*external surface*), auditory meatus, upper ear, dura matter (posterior cranial fossa)

Vagus (X) Palsy: - Palsy: a. Hoarseness, dysphagia, dysarthria b. Loss of gag reflex c. Loss of sensation pharynx and larynx d. Weak side of __________ collapses (lower) ****e. Uvula deviates ________ from affected side - Hemodynamic effects: a. Unopposed sympathetic stim of heart b. result is Inc HR

Vagus (X) Palsy: - Palsy: a. Hoarseness, dysphagia, dysarthria b. Loss of gag reflex c. Loss of sensation pharynx and larynx d. Weak side of *palate* collapses (lower) e. Uvula deviates *away* from affected side - Hemodynamic effects: a. Unopposed sympathetic stim of heart b. result is Inc HR

Vagus (X): - Motor, sensory - Taste epiglottis - Swallowing (____________=vagus) - _________ elevation - Midline Uvula - Talking - Coughing - Autonomic system a. Aortic arch chemo/baroreceptors

Vagus (X): - Motor, sensory - Taste epiglottis - Swallowing (*dysphagia*=vagus) - *Palate* elevation - Midline Uvula - Talking - Coughing - Autonomic system a. Aortic arch chemo/baroreceptors

Vestibulocochlear (VIII): - Sensory - Equilibrium, balance, hearing - Vestibular portion: a. ________________ eye movements b. lesions: vertigo, nystagmus, disequilibrium - Cochlear portion: a. hearing b. lesions: tinnitus, hearing loss - Testing: if warm or cold water in ear yields no _____ response, lesion is on that side

Vestibulocochlear (VIII): - Sensory - Equilibrium, balance, hearing - Vestibular portion: a. *Compensatory* eye movements b. lesions: vertigo, nystagmus, disequilibrium - Cochlear portion: a. hearing b. lesions: tinnitus, hearing loss - Testing: if warm or cold water in ear yields no *eye* response, lesion is on that side