• movements cannot be initiated but the LMN still receives information from chemicals in nervous system that can excite them
• leads to spasticity (overly tight muscles) plus weakness
• can cause reflexes to be overly sensative
• may regress to old reflexes they should no longer have (i.e. from infancy)

• muscles will not contract because info can't be sent out to muscles despite receiving info from UMN
• can cause flaccidity, paralysis, and atrophy 
• (ex) Bells Palsy

• inflamed nerve that sends info to facial muscles
• can cause facial droop and inability to move that side of the face

What is fasciculation?

Where does it often occur?

• muscle fibers twitching
• often occurs in the tongue

Upper Motor Neuron --> Brainstem --> Muscle

2 neurons involved

• sensory receptor --> brain stem --> thalamus --> sensory strip
• 3 neurons involved

What is the path of the first order neuron?

Which is actually the cranial nerve?

First, second, or third order neuron

What are the three ways of categorizing cranial nerves?

(not meaning motor, sensory, or both)

1. Function
2. Innervation
3. Type of Information Carried

1. General
2. Special

• muscles involved were derived differently during gestation
• involves special senses that can only occur in one place (i.e. vision, hearing, taste)

1. Somatic -- skeletal muscles
2. Visceral -- organs and/or specialized muscles

• Afferent -- sensory
• Efferent -- motor

What would a General, Somatic, Efferent nerve do?

Examples?

• sends motor info to skeletal muscles (not specialized)
• primarily ocular (eyes) and the tongue

What would a General, Visceral, Efferent neuron do?

Examples?

• sends motor info to organs (usually glands)
• autonomic glands and smooth muscles
• may regulate things like pupil constriction and gland secretion (i.e. saliva)

What muscles are controlled by Special, Visceral, Efferent nerves?

(THE ONES IMPORTANT FOR SLPs!!)

Muscles for:

• phonation*
• mastication*
• swallowing*
• articulation*
• head turning
• shoulder raising

What is the path of a general somatic afferent nerve?

What senses are involved?

• brings general sensory info f/ head, neck, and face
• pain, pressure, temperature, and touch

What senses are involved in general visceral afferent nerves?

Where areas of the body are involved?

• pain, pressure, temperature, touch
• pharynx, larynx, palate, aorta, and abdomen

• vision, hearing, and vestibular (balance) systmes
• proprioception (awareness of body parts in space)

1. Olfactory
2. Optic
3. Oculomotor
4. Trochlear
5. Trigeminal**
6. Abducens
7. Facial
8. Vestibulocochlear (auditory/acoustic)
9. Glossopharyngeal**
10. Vagus**
11. Accessory (spinal)
12. Hypoglossal**

• I. Olfactory
• II. Optic

1. Where are receptors located for CN I - Olfactory?
2. What view can CN I be seen in the brain?
3. Is CN I sensory, motor, or both?

1. mucosal membrane of the nose
2. ventral view and before the brainstem
3. sensory only

How is CN I - Olfactory categorized based on:

-Function

-Innervation

-Type of Info

Special

Visceral

Afferent

What other CN does CN I connect with?

What are the results?

• connects with CN V - Trigeminal
• allows us to respond to noxious odors (i.e. facial expressions)

• Limbic System -- allows integration of smells with memories and emotions

• reduced sense of smell
• typically begins at 65 y/o

• monocular blindess; hemianopsia
• complete blindness in one eye; half the visual field is lost

III. Oculomotor

IV. Trochlear

VI. Abducens

bundle of fibers that conects cranial nerves

III, IV, and VI

What types of components does the oculomotor nerve (III) have?

general/special

visceral/somatic

efferent/afferent

GVE - general visceral efferent

GSE - general somatic efferent

innervates 4 out of the 6 ocular muscles

• superior rectus - pulls eye up and in
• medial rectus - adducts eye (pulls toward center)
• inferior rectus - pulls eye down and in
• inferior oblique - contributes to up and out gaze
• levator palpebrae superioris - lift eyelid

droopy eyelid

damage to the levator palpebrae superioris muscle

Where does the GVE component of CN III begin?

Where does it go/what does it innervate?

What does this accomplish?

What other CN is this related to and why?

• Begins at the Edinger Westphal Nucleus
• goes to/innervates the iris
• allows contriction of the pupil in response to light
• r/t CN II because it detects the light

What is external opthalmoplegia?

What causes it?

• paralysis of ocular muscles
• eye can't move to midline
• caused by lesion to CN III

What is lateral strabismus?

What causes it?

• eye deviates to lateral position & can't move midline
• r/t external opthalmoplegia so caused by lesion to CN III

right eye 

same sided eye involvement as side of lesion

What is diplopia?

What is the cause?

• double vision 
• lack of conjugate gaze
• caused by unilateral lesion to CN III

What is the only CN to exit the brainstem dorsally?

Where exactly does it exit?

IV. Trochlear

exits just below colliculi (aka corpora quadrigemina)

Is CN IV (Trochlear) sensory, motor, or mixed?

What type of innervation does it have?

general/special

visceral/somatic

efferent/afferent

Motor Only

GSE (general somatic efferent)

What does the GSE component of CN IV innervate?

What does this allow?

one skeletal eyeball muscle

allows eye movement down and laterally

What is the nucleus for CN IV?

What is its pathway?

"motor nucleus of the trochlear"

sends LMN to innervate the superior oblique muscle of the eye

What can result from paralysis of the superior oblique muscle of the eye?

What CN is involved?

• can result in fixed gaze in upward medial position
• diplopia can be present as well
• Trochlear (CN IV) is involved

1. Face
2. head
3. oral & nasal cavities
4. sinuses
5. teeth
6. anterior 2/3 of tongue
7. sensation for part of pinna
8. ear canal 
9. external tympanic membrane

1. Opthalmic
2. Maxillary
3. Mandibular

What 2 classifications of nerves can be applied to the trigeminal nerve?

general/special

somatic/visceral

efferent/afferent

General Sensory Afferent (GSA)

Special Visceral Efferent (SVE)

• Where is the ophthalmic branch (sensory) branch of CN V located?

• What areas does it innervate?

1. near eyes
2. forehead 
• anterior scalp 
• eyeball 
• upper eyelid 
• cornea, anterior & lateral nose 
• frontal & nasal sinuses

1. What is the maxillary branch of CN V near?
2. What areas does it innervate?

1. near upper jaw
2. innervates:
• temples
• posterior nose
• upper cheeks
• lower eyelids
• upper lip
• upper oral cavity (including palate)

1. Where is the mandibular branch of CN V located?
2. What areas are innervated by this branch?
3. Does it offer sensory, motor, or mixed info?

1. near lower jaw
2. brings info from:

• sides of scalp
• lower oral cavity
• ear canal
• ear drum
• pinna
• anterior 2/3 of tongue

1. also contains motor abilities

• After the semilunar ganglion, where does info from CN V go?
• What are the functions of each component of this area?

• goes to trigeminal nuclear complex 
• 3 Components:
• discriminative touch (touching cheek or forehead?)
• pain & temperature
• proprioceptive info from the jaw
• how open/closed is the mouth, where do my lips need to be?, chewing, swallowing, etc.

What is the nucleus for the SVE component of CN V?

Where is it located?

motor nucleus of the trigeminal

sits in pons area

• muscles for mastication
• internal/external pterygoids
• masseter
• temporalis
• anterior digastric
• tensor villi palatini
• tensor tympani

What does the anterior digastric muscle do?

Which nerve and component controls it?

• controlled by motor nucleus of the trigeminal nerve
• elevates larynx to protect airway
• helps with swallowing and elevating pitch

What does the tensor villi palatini do?

Which nerve and component controls it?

• controlled by motor nucleus of trigeminal
• tenses soft palate out to sides
• helps with closure of velopharyngeal port
• prevents hypernasality and keeps food from getting into nose

What does the tensor tympani do?

Which nerve and component controls it?

• controlled by the motor nucleus of the trigeminal
• contracts the tympanic membrane to protect against loud noises

ipsilateral

same side

Which reflexes would be lost if damage occurred to the trigeminal nerve?

So what does that mean...

Sneezing and Blinking reflexes lost

• so can't sense that the eye is dry to signal blinking
• can't sense irritation to nose to signal sneezing

What is trigeminal neuralgia (aka tic douloureux)?

Where does it usually occur?

What is the treatment?

• intense stabbing/burning pain along CN V
• usually occurs along ophthalmic or mandibular branches
• usually have to cut the nerve to stop the pain

A person has ipsilateral paralysis of the muscles of mastication ... 

What will he look like during an attempt to protrude the jaw?

What will a person look like who has bilateral paralysis of ipsilateral muscles of mastication?

What are some symptoms?

the mouth will hang open causing...

hypernasality

difficulty w/ speech and chewing

What type of component does CN VI (abducens) have?

What muscle(s) does it innervate?

General Somatic Efferent

lateral rectus

Which nerve innervates the lateral rectus muscle?

What does it do?

Abducens (CN VI)

moves eye straight out to the side

eye will be stuck at midline

diplopia can ocur

III. Oculomotr

IV. Trochlear

VI. Trigeminal

What components does the facial nerve (CN VII) have?

general/special

somatic/visceral

afferent/efferent

GVE - general, visceral, efferent

SVA - special visceral afferent

SVE - special visceral efferent

What is supplied by the GVE component of CN VII (facial)?

What branch of the nervous system do these fall under?

one major saliva gland + tear glands

autonomic nervous system

What muscles are innervated by the SVE component of CN VII (facial)?

List some types of actions this allows...

all muscles for facial expression

lip rounding, blowing, speaking, smiling, raising eyebrows, grimacing, etc.

What do the buccinator muscles allow us to do?

Which nerve controls them?

• controlled by CN VII (facial)
• allows to make fish face, suck through straw, move food out of cheeks

posterior digastric

stylohyoid

controlled by SVE component of CN VII (facial)

it dampens loud noise in the ear

all sounds seem too loud

lesion to CN VII (facial)

• paralysis of ipsilateral face (same side as lesion)
• excessive secretion from glands
• loss of taste for the anterior 2/3 of the tongue

The facial nucleus is split in half.  

How is each half innervated and

what part of the face is involved?

• lower face is contralaterally innervated by the UMN
• upper face is bilaterally innervated

What disorder may result from a bilateral UMN lesion on the facial nerve?

What are some signs/symptons of this?

• pseudobulbar palsy
• unable to inhibit emotions
• laugh or cry suddenly (may seem like for no reason)
• emotional lability (emotions all over the place)

How is facial movement impacted by a bilateral UMN lesion of the facial nerve?

What may occur with a significant emotional stimulus?

• face may seem unable to move
• muscle spasm may occur w/ significant emotional stimulus

Lower Motor Neuron syndrome of the facial nerve

(CN VII)

What causes Bell Palsy?

What results?

Is it treatable?

• inflammation or infection of CN VII (facial) often causes it
• sudden ipsilateral facial paralysis
• reversible when inflammation subsides

What sense is associated with CN VIII (vestibulocochlear)?

Is it motor, sensory, or mixed?

• sensory only
• auditory/acoustic, vestibular system (balance)

How is CN VIII (vestibulocochlear) classified?

general/special

somatic/visceral

afferent/efferent

Where does it enter the brain?

• Both branches are SSA (special, somatic, afferent)
• Enters most laterally at the pontomedullary junction

• cerebellum
• spinal cord
• reticular formation (in brainstem; arousal/wakefulness)
• medial longitudinal fasciculus (visual feedback for balance)

mixed:

glosso -- sensory

pharyngeal -- motor

What classifications does CN IX (glossopharyngeal) have?

general/special

somatic/visceral

afferent/efferent

GVA

GVE

SVA

SVE

pain, temperature, touch, pressure from intraoral viscera:

• throat
• tonsils
• Eustachian tube
• middle ear
• soft palate
• posterior 1/3 of the tongue

gag and respiratory reflexes

What areas are innervated by the GVE component of CN IX (glossopharyngeal)?

What type of innervation?

autonomic innervation to:

2 major saliva glands

cardiac muscle

What CN innervates the stylopharyngeus muscle?

What does this muscle do?

CN IX (glossopharyngeal)

elevates pharynx

helps squeeze food down

What CN innervates the superior pharyngeal constrictor muscle?

What does this muscle do?

CN IX (glossopharyngeal)

important for velopharyngeal closure

• difficulty swallowing r/t lack of pressure & strength
• loss of taste & general sensation for ipsilateral posterior 1/3 of tongue
• loss of gag reflex

What is the vagus nerve (CN X) responsible for?

voice

phonation

swallowing

most of the work for resonance

What does the GVA component of CN X control?

What would happen if it sensed something "going down the wrong way" in the throat?

pain, temperature, touch, pressure to:

• pharynx
• larynx
• thorax
• abdomen
• heart
• esophagus

would stimulate cough/gag reflex

cardiac muscles

esophagus

intestines

dorsal motor nucleus

taste from:

base of tongue

epiglottis

pharynx

larynx

pharynx

larynx

upper esophagus

What type of innervation does CN X receive from the UMN? 

How would a unilateral stroke impact this nerve?

bilateral innervation by UMN

unilateral stroke would not greatly impact CN X because of bilateral innervation

Pharyngeal

Superior Laryngeal

Recurrent Laryngeal

almost all muscles of VP closure:

• 2 lift the velum
• levator vili palatini
• uvulus
• Pharyngeal Constrictors:
• helps with superior constrictor
• completely controls middle and inferior constrictors

can cause hypernasality

nasal regurgitation may also occur

reflux of fluids into the nasopharynx and nasal cavities during drinking or vomiting

What does the superior laryngeal branch of CN X innervate?

What does this do?

cricothyroid muscle:

tenses vocal folds to increase pitch

• What areas are sensed by the superior laryngeal branch of CN X?
• Why is this important? (When might this be helpful?)

• senses parynx and larynx down to vocal folds
• helpful in sensing when something starts down the wrong pipe

very long branch!

goes down into the thorax and back up into the larynx

The recurrent laryngeal branch of CN X handles all but intrinsic laryngeal muscles except the  ___________ .

What role does the recurrent laryngeal branch of CN X play in vocal fold movement?

So what can and can't it do?

• cannot help increase pitch
• adducts vocal folds (brings them together)
• helps with swallowing
• abducts vocal folds (opens up)
• helps breathe
• relaxes vocal folds
• for low pitch

• gag
• cough
• vomit
• swallow

What would result from a lesion on the vagus nerve where all 3 branches are still together?

• vocal quality -- monotone, hypernasal, breathy
• poor swallowing protection
• nasal regurgitation possible with swallowing

• hypernasality
• nasal regurgitation
• weak constrictors leading to inefficient ability to squeeze food down

• affected side of palate wil hang lower (so left sided damage = left side hangs down)
• uvula pulls toward good side during phonation

• aphonic (inability to speak)
• can't cough
• issues with swallowing
• possible stridor

lowest exiting nerve

exits spinal cord at rootlets

rootlets will rejoin before exiting at the medulla

Which muscles are innervated by CN XI (spinal/accessory)?

How might this impact us as SLPs?

• trapezius and sternocleidomastoid muscles
• can impact nonverbal gestures

What nerve does CN XI follow?

Why does this matter?

• follows CN X (vagus)
• important because if one is damaged the other is probably damaged too

• drooped shoulder on same side as lesion
• restricted head movement

Where is the motor nucleus of CN XII (hypoglossal) located?

Where does it exit?

medulla

exits lateral medulla between CN X and XI

What is impacted by a unilateral stroke to the left UMN of the hypoglossal nerve (CN XII)?

What is the result?

• right hypoglossal nucleus loses innervation
• results in spasticity/weakness of the tongue

What does the GSE component of CN XII control?

• pretty much all intrinsic/extrinsic muscles of tongue

What else does CN XII have connections with?

Why is this important?

• nucleus solitarius that brings sensory info f/ vagus nerve
• important because this helps in the tongue's role in chewing and sucking

ipsilateral tongue paralysis (same side as lesion)

• flaccid, weak tongue will begin to atrophy
• one side will start looking shriveled over time
• fasciculations
• expect dysarthria
• can't move food around in the mouth -- chewing/swallowing problems
• tongue deviates to side of lesion on protrusion

severe dysarthria & swallowing problems

s/s of end stage ALS

fasciculations

contralateral problems -- 

left sided lesion will result in right sided tongue paralysis

nerve fibers "jumping" as they die off

kind of looks like jell-o in the mouth with the tongue wiggling around

Which fibers are impacted in Locked-In Syndrome?

What is the result?

descending motor fibers heading to the medulla to cross over are interrupted by the lesion

no motor impulses are able to cross over at medulla so info isn't sent to spinal cord to tell body what to do

pretty much paralyzed except for the eyes!

vertical eye movement

if lucky, may be able to blink

motor function below pons basically stops

• quadriplegia
• loss of all motor spech -- tongue, lips, palate, vocal folds, etc.
• awareness and comprehension are intact!