1. FACE Which cranial nerves supply sensory and motor functions of the face and associated structures (e.g. hard palate, teeth and gums)?

2. 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
Skin of external ear and external auditory canal: Vagus (X), with some assistance by V, for tragus V
It is branches of V that are numbed by the dentist when you have dental work

3. Branching of V V (Trigeminal): 3 branches Ophthalmic: Sensory
Maxillary: Sensory
Mandibular: Sensory (+motor of mastication, which we’ll study later) V V

4. 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

5. 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

6. 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.

7. 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)

8. 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

9. 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)

10. FACE Clinical Applications

11. 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

12. 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

13. TONGUE Which cranial nerves supply sensory and motor functions of the tongue?

14. Tongue, Sensory Tongue, Motor
General sensory (touch)
Anterior 2/3 of tongue:
V, trigeminal nerve, mandibular branch
Special Sensory (taste)
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.

15. 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?

16. 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).

17. 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)

18. 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

19. 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)
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

20. 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

21. LOWER JAW Which cranial nerves supply muscles used for movements of mandible (for speaking and eating?)

22. Sensory
Motor
Muscles of mastication
Trigeminal V
(proprioception from jaw)
Trigeminal V, mandibular 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

23. Jaw movement, V (Trigeminal, mandibular branch)
Motor input to muscles that
Close and open the jaw
Move the jaw laterally (grinding and lateral movements)

24. 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)

25. 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)

26. 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?

27. Sensory Motor Soft palate IX (Glossopharyngeal)
V (Trigeminal), flatten and tense
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.

28. 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)

29. 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)

30. 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/

31. 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

32. PHARYNX Which cranial nerves supply muscles used for sensation in, and movements of, pharynx, important for swallowing and gag reflex?

33. Sensory
Motor
Pharynx
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.

34. Sensory innervation of pharynx
Glossopharyngeal (IX) Mediates sensation from
Soft palate
Posterior 1/3 of tongue
Tonsils and faucial pillars
Pharynx

35. Motor innervation of pharynx
Note: damage to the innervation of the parotid would result in EXCESSIVE salivation
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

36. 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
Dysphagia = swallowing disorder

37. 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 ….)

38. LARYNX Which cranial nerves supply muscles used for sensation in, and movements of, larynx, important for voicing and for protection of airway when swallowing?

39. Larynx has sensation, and laryngeal muscles, intrinsic and extrinsic:
Sensory
Motor
Larynx
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

40. 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

41. Laryngeal INNERVATION
X (Vagus)
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 X

42. Motor innervation of larynx
Laryngeal branches of vagus nerve (X)
Superior laryngeal
External branch
Recurrent laryngeal

43. 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 re-ascends.
Recurrent laryngeal nerve is vulnerable in heart and thyroid surgeries

44. 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;
motor to most of the intrinsic muscles of the larynx, except cricothyroid
Recurrent laryngeal nerve is vulnerable in heart and thyroid surgeries

45. 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

46. 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

47. 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.)

48. 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?

49. Sensory Motor Head/ shoulders
-- (spinal cord innervates sensory from shoulders and back of head)
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

50. XI: Accessory, spinal accessory
Connects at the spinal cord (spinal root of XI) and medulla (cranial root of XI)

51. 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

52. 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)

53. 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

54. Testing XI Head turning Shoulder shrugging Lift arm above shoulder
Turn head
Turn head to resistance
Shoulder shrugging
Shrug shoulders
Shrug shoulders to resistance
Lift arm above shoulder

55. 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?