Download Cranial nerves of face, tongue, jaw, palate, larynx, shoulders

FACE
Which cranial nerves supply
sensory and motor functions of the face and
associated structures (e.g. hard palate, teeth and gums)?
Sensory from face (Think of a face
with teeth bared, and eyes and nares
open flared): Trigeminal nerve (V)
• Cutaneous sensations from face (pain,
temp., touch): Trigeminal (V)
– Proprioception from face: Facial (VII)
• Touch from cornea of eye and nasal
•
mucosa (V, ophthalmic branch)
Teeth and gums: Trigeminal (V)
– Maxillary branch: upper teeth and gums, plus
hard palate
– Mandibular branch: lower teeth and gums,
plus lower jaw and inside of cheek
V
V
It is branches of
V that are
numbed by the
• Skin of external ear and external auditory dentist when you
canal: Vagus (X), with some assistance by have dental work
V, for tragus
Branching of V
• V (Trigeminal): 3 branches
– Ophthalmic: Sensory
– Maxillary: Sensory
– Mandibular: Sensory
(+motor of mastication,
which we’ll study later)
V
V
Testing Sensory of V in face
• Sensory of V (trigeminal): With
•
eyes closed, stroke…
– above eyebrows (tests
ophthalmic branch)
– upper lip (tests maxillary
branch)
– between lower lip and chin
(tests mandibular branch)
If you touch the pinna or ear
canal you’re testing X (vagus). V
innervates only the tragus
It is branches of V
that are numbed by
the dentist when you
have dental work
Motor innervation to
muscles of facial
expression: VII (facial)
Fibers
cross
Fibers
don’t
cross
• Remember:
– Bilateral UMN innervation
to the upper face
– Unilateral UMN
innervation
(contralateral) to the
lower face
– LMNs (facial nerve VII
and its branches)
innervate the whole face
on the same side as the
cranial nerve
Upper face:
Mostly
contralateral,
some ipsilateral
Lower face:
Contralateral
only
Motor innervation to muscles of
face: VII (facial)
• Notice how cranial
nerve VII (facial) exits
the cranium at the
internal acoustic
meatus (one of the
foramina in the
cranium), which is
intimately close to the
inner ear. It exits here
with VIII.
Branching of VII
• VII (Facial)
branches
– SVE to muscles of
facial expression
(including muscles
for tight closure of
eye) in yellow
– GVE to lacrimal
glands, nasal
mucosa and some
salivary glands (red)
Note that VII also
mediates proprioception
from face receptors
(embedded in muscles)
Motor innervation to certain glands near/around
face/mouth
• Facial nerve (VII) also mediates
– Visceral innervation (in red) to
• lacrimal glands,
• nasal mucosa and
• some salivary glands:
Submandibular and sublingual
(#2 and #3 below)
VII
Note that VII also innervates
stapedius muscle
• VII: Dampens vibrations of the ossicles
associated with loud noises (stapedius
muscle)
• V: Dampens vibrations of the ossicles
associated with the noise of chewing
(tensor tympani)
FACE
Clinical Applications
Pathology of motor of face (VII)
• Motor of VII
– Upper motor neuron lesion, e.g. cerebral stroke
• Complete involvement below eye, some involvement
around eye, little difficulty with forehead and frontalis
muscle. (Note: Only applies to voluntary movement, not
emotionally initiated movements.)
– Lower motor neuron lesion: Moebius syndrome,
biilateral congenital atrophy of VII
– LMN lesion: Bell’s palsy, unilateral compression, viral infect.
• Paralysis of entire side of face ipsilateral to the site of
the compression or infection
• Problems with eyelid closing
• Drooping corner mouth
• (Taste on anterior 2/3 of tongue affected)
• Poor production of tears, reduced salivation
Testing motor of VII in face
• Motor (voluntary) of VII (See pg. 156 of W&A)
•
•
– Face at rest (look for asymetry)
– Wrinkle forehead and look up
– Close eyes as tightly as possible
– Smile, pucker, pout
Whole side of face affected = _______ lesion on
ipsilateral side, associated with _____________
dysarthria
Lower face affected, with some weakness of upper
face = _________ lesion on contralateral side,
associated with ___________________ dysarthria
TONGUE
Which cranial nerves supply
sensory and motor functions of the tongue?
Tongue, Sensory
General sensory
(touch)
Anterior 2/3 of
tongue:
V, trigeminal
nerve,
mandibular
branch
Tongue, Motor
Special Sensory
(taste)
Anterior 2/3 of
tongue:
VII, facial nerve
All tongue movement
(All four intrinsic and all
three extrinsic tongue
muscles)
XII (Hypoglossal)
General and special sensory (touch
and taste)
Posterior 1/3 of tongue:
IX, glossopharyngeal nerve
Tongue has sensation of two types (touch and taste) and is also
able to move. Each of these functions is filled by different
cranial nerves.
General sensory: Touch on tongue
• V (Trigeminal), mandibular
•
branch
– General sensory for
anterior 2/3 of tongue
IX (Glossopharyngeal)
– General sensory for
posterior 1/3 of tongue.
Do you remember the other sensory
functions of V? (think of face,
gums, teeth, hard palate, jaw).
When the mandibular branch of V is
damaged or anesthetized, what
sensory functions would be
affected?
Special sensory: Taste on tongue
• VII (Facial)
•
– Special sensory for anterior
2/3 of tongue, in green on
diagram to right.
IX (Glossopharyngeal)
– Special sensory for posterior
1/3 of tongue.
Remember these
women who have VII
(facial nerve)
involvement? They’ll
also have problems
with taste on the
___________________
_ of tongue.
Do you remember the cranial
nerve of smell (I)? It works
with VII and IX (taste).
Clinical testing of sensory
functions of tongue
• Swab dipped in flavored solution
• Tests taste (function of special sensory branch of VII)
• Tests touch (function of mandibular branch, general
sensory, of V)
Motor functions of tongue,
Hypoglossal (XII)
• Motor input to muscles that
– Change the tongue’s
shape
• Shorten, narrow,
elongate, flatten and
make concave
– Move the tongue
through space
• Protrude, draw
tongue up and back,
retract and depress
Testing tongue movement (looking for
injury of c.n. XII, i.e., LMN)
• Protrude tongue (deviation to side of injured
•
•
•
cranial nerve (LMN); protrusion of stronger side
overcomes weaker)
– Freely and against resistance
Lateralize tongue to corners of mouth or to internal cheek
(inability to lateralize on side of injured cranial nerve, e.g. XII
damaged on R  can’t lateralize to R)
– Freely and against resistance
Elevate tongue while you hold chin down
Look for involuntary movements (facsiculations, fibrillation)
and wasting away (atrophy) of the tongue
– Fasciculations are small muscle twitches, which look like
little, moving dimpling of tongue; moving corrugations
– Fibrillation looks like a fast tremor
Clinical presentation of tongue
in different dysarthrias
• Flaccid dysarthria: Look for atrophy, changes in
•
•
•
functional ability and involuntary movement of
tongue as described on previous slide
Spastic dysarthria: Articulation is imprecise and
distorted because muscles are too tight
Ataxic dysarthria: Articulation is sometimes
precise, sometimes not, due to discoordination
Hyperkinetic dysarthria: Tongue may move
involuntarily
LOWER JAW
Which cranial nerves supply
muscles used for movements of mandible
(for speaking and eating?)
Sensory
Motor
Muscles of Trigeminal V
Trigeminal V,
mastication (proprioception mandibular
from jaw)
branch
(movement of
jaw)
You have to be able to move mandible
(lower jaw) for chewing (mastication) and
speaking, and sense how jaw is positioned
Jaw movement, V (Trigeminal,
mandibular branch)
• Motor input to muscles that
– Close and open the jaw
– Move the jaw laterally (grinding and
lateral movements)
Pathology of motor V
• Motor of V (trigeminal): Lower motor neuron
lesion of mandibular branch
– Flaccid paresis or paralysis of the ipsilateral
muscles of mastication
– Slight deviation of jaw to the same side as the
damaged LMN
• Unilateral upper motor neuron disease unlikely
to affect function, because of bilateral
innervation
– Transitory or mild paresis (i.e., slight or partial
paralysis)
Testing motor of V (LMN damage)
• Motor of V (trigeminal): Mandibular
branch
– Palpate area of masseter as patients bites
down as hard as possible, then relaxes
• Feel for bulk of the muscle
– Look for atrophy of the temporal muscle:
Shrunken area at the temple of the face?
– Jaw closing while you hold chin down and
forehead in place
• Ask patient to bite down hard against resistance of
your hand
– Jaw opening with resistance under chin
– Ask patient to move jaw side to side
– Ask client to articulate phonemes that require
jaw movement (e.g. bilabials)
SOFT PALATE
Which cranial nerves supply
muscles used for movements of soft palate,
used for controlling nasality, and for keeping food out of nasal
passages when swallowing?
Sensory
Motor
V (Trigeminal),
Soft IX
(Glossopharyngeal) flatten and tense
palate
X (Vagus) most
innervation of
soft palate
Soft palate has sensation, and is also able to move.
Each of these functions is filled by different cranial
nerves.
Sensory innervation of soft palate
• Glossopharyngeal (IX)
Mediates sensation from
– Soft palate
– Posterior 1/3 of tongue
– Tonsils and faucial pillars
– Pharynx (which we’ll see in
upcoming slides)
• IX also mediates sensation
from the middle ear
(tympanic cavity and
Eustachian tube)
Motor innervation of soft palate
• Vagus (X)
•
– Provides primary
innervation to soft palate
V (Trigeminal)
– Partially responsible for
flattening and tensing of
soft palate
– Opens Eustachian tube
– (Remember that it also
innervates jaw muscles)
Clinical testing of movement of
soft palate
• Motor (V & X): Soft palate
should
– raise symmetrically on
repeated production of /a/.
– Raise sufficiently so that no
nasality is heard on oral sounds
– Raise completely and
symmetrically as part of gag reflex
• Do this test only if speech is
hypernasal and no movement is seen
on repeated /a/
Clinical presentation for
dysarthria of soft palate
• Flaccid dysarthria: Consistently hypernasal,
because soft palate cannot lift at all, or lifts
only on one side (see previous slide)
• Spastic dysarthria: Consistently hypernasal,
muscles can’t reach posterior pharynx
• Ataxic dysarthria: Occasional, inconsistent
hypernasality; can’t coordinate timing of
palate lifting
PHARYNX
Which cranial nerves supply
muscles used for sensation in, and movements of, pharynx,
important for swallowing and gag reflex?
Sensory
Pharynx
Motor
IX (Glossopharyngeal) IX (Glossopharyngeal)
lateral dilation + some
elevation
X (Vagus)
constrictors
Pharynx has sensation, and is also able to
move. Each of these functions is filled by
different cranial nerves.
Sensory innervation of pharynx
• Glossopharyngeal (IX)
Mediates sensation from
– Soft palate
– Posterior 1/3 of tongue
– Tonsils and faucial pillars
– Pharynx
Motor innervation of
pharynx
• IX, glossopharyngeal
•
– Lateral dilation and some
elevation of pharynx via
stylopharygeus muscle (#1)
• Helps clear pharynx
– Visceral motor innervation of
parotid gland (#1 on right)
X, vagus, pharyngeal branch
– Pharyngeal constrictors:
moves bolus of food toward
esophagus
• Remember that X also
innervates most muscles of soft
palate
Note: damage to
the innervation
of the parotid
would result in
EXCESSIVE
salivation
Phases of
swallow
require the
use of both:
• Afferent
(sensory) neural
pathways from
pharynx
– Stimulation of IX
initiates the
swallow
• Efferent (motor)
neural pathways
to pharynx
– X provides
motor
innervation to
the pharyngeal
constrictors, to
move the bolus
down
Testing sensory and motor of pharynx
• Gag reflex (sensation precedes motor activity)
– Sensory portion of reflex
• Glossopharyngeal (IX)
– Motor portion of reflex: Gag response
• Glossopharyngeal (IX): Elevation and dilation of
pharynx; lifting of soft palate
• Vagus (X): Contraction of the pharyngeal muscles,
– If no gag response, ask “Did you feel the
touch/poke?” If answer is yes, then just motor
portion of gag is involved (X).
(Think of the last time you had a
test for strep ….)
LARYNX
Which cranial nerves supply
muscles used for sensation in, and movements of, larynx,
important for voicing and
for protection of airway when swallowing?
Larynx
Sensory
Motor
X (Vagus)
X (Vagus)
Intrinsic muscles of larynx
V (Trigeminal)
VII (Facial)
IX (Glossopharyngeal)
Extrinsic muscles of larynx
Larynx has sensation, and laryngeal muscles,
intrinsic and extrinsic:
Both sensory and motor functions help us to
protect airway
Motor functions help us to produce voicing
Sensory innervation of larynx
• Vagus (X) Mediates
sensation from larynx
– Lets you know when
foreign body has
entered larynx
– Senses pain, e.g. in
cases of laryngeal
cancer
Laryngeal INNERVATION
• X (Vagus)
•
X
– Sensory (lets you know
when foreign body is in
larynx)
– motor to intrinsic muscles of
larynx (changes voice)
Movements of whole larynx to
protect airway:
– V (trigeminal): assists with
superior and anterior movement
of larynx
– VII (facial) assists with superior
and posterior movement of larynx
– IX (glossopharyngeal): assists
with elevation of larynx
Motor innervation of larynx
• Laryngeal branches of
vagus nerve (X)
– Superior laryngeal
• External branch
– Recurrent laryngeal
Note X (vagus) and
its branches
• Pharyngeal
• Laryngeal (descends)
– Superior laryngeal (#1)
• Internal branch
• External branch
– Recurrent laryngeal (#6)
Note how it descends
considerably below the
larynx, and then reascends.
Recurrent laryngeal nerve
is vulnerable in heart and
thyroid surgeries
Functions of each of the branches of laryngeal
nerve (which itself is a branch of X vagus)
• (Pharyngeal)
• Laryngeal (descends)
– Superior laryngeal (#1)
• Internal branch: Sensory above
true vocal folds, including
epiglottis and base of tongue
• External branch: Motor to the
cricothyroid muscle (for pitch
changes)
– Recurrent laryngeal (#6):
• Sensory of true vocal folds and
below;
Recurrent laryngeal nerve is
• motor to most of the intrinsic
muscles of the larynx, except vulnerable in heart and thyroid
surgeries
cricothyroid
Note:
• Vagus also supplies
afferent and efferent
visceral innervation, e.g.
– Heart
– Respiratory system
– Most of digestive system
• Afferent innervation and
most efferent visceral is
not appreciated at
conscious level
Pathology at laryngeal level
• Silent aspiration of food into lungs when sensation is affected
•
•
– internal branch of superior laryngeal
– recurrent laryngeal
Test with modified barium swallow
With damage to V, VII, IX, ability to move larynx up and
under tongue for protection of airway may be affected
Dysphonia /aphonia when motor functions of larynx are
affected (X), via damage to the
– External branch of superior laryngeal, which will affect
ability to change pitch
– Recurrent laryngeal branch of laryngeal of X, which will
affect voice quality overall
Test with laryngoscopy and clinical voice evaluation
Clinical presentation of
dysarthria at the laryngeal level
• Flaccid dysarthria: Voice becomes breathy, and phrases
•
•
•
•
short, ‘cause folds can’t close properly; food may be aspirated
(because glottis doesn’t close)
Spastic dysarthria: Voice becomes harsh, strained-strangled,
with reduced range of stress and loudness, ‘cause vocal
muscles are too tight
Ataxic dysarthria: A coarse tremor of the vocal folds; pitch
goes up and down. Air support is also uncoordinated, so
there is occasional excessive loudness
Hypokinetic dysarthria: Monopitch because vocal muscles
cannot initiate larger movements. Diaphragm does not move
fully, so voice is monoloud, with low intensity
Hyperkinetic dysarthia: Voice stoppages and breaks;
excessive loudness variation from involuntary diaphragm
mvmt.)
MUSCLES OF HEAD TURNING AND
SHOULDER SHRUGGING
Which cranial nerves supply
muscles used for head turning and shoulder shrugging,
important for visual scanning and communication?
Sensory
Head/
-- (spinal cord
shoulders innervates
sensory from
shoulders and
back of head)
Motor
XI (Spinal
accessory)
moves head and
shrugs shoulders
We need to turn head both to receive communication
effectively and to shake our heads ‘no’
We need to shrug shoulders to communicate, and also
to lift arm when communicating via pointing
XI: Accessory, spinal accessory
Connects at the spinal cord (spinal root of XI)
and medulla (cranial root of XI)
Note XI (spinal accessory) and its two roots
• Cranial root (from
medulla)
– Joints X (vagus) and is
“accessory” to the
functions of X
• Spinal (from spinal cord)
– Muscles that turn, tilt
and thrust head
forward
– Muscle that shrugs
shoulders
A more careful look at the muscles that
turn head and shrug shoulders
• Sternocleidomastoid (#1 on left)
• Trapezius (trapezoidal surface muscle in picture
on right)
Pathology (example of damage
to right cranial nerve XI)
• Difficulty turning head
•
•
away from the side of the
injured nerve (right
sternocleidomastoid turns
head to the left)
Drooping shoulder on side
of injured nerve
Difficulty with arm
movements above the
shoulder on the affected
side
Testing XI
• Head turning
– Turn head
– Turn head to resistance
• Shoulder shrugging
– Shrug shoulders
– Shrug shoulders to resistance
• Lift arm above shoulder
MINI SELF-TEST
Which cranial nerves exit the cranium together, and thus
“pattern” when damaged? What functions do these cranial
nerves fill, and thus, what functions may be simultaneously
affected?