1. LAB EXERCISE 11
CRANIAL NERVES

2. Cranial Nerves Twelve pairs of cranial nerves
That arise from the brain
Each nerve is identified by a Roman number
I through XII
and a name

3. Cranial Nerves Four Classifications of Cranial Nerves Sensory nerves
**Carry somatic sensory information, including touch, pressure, vibration, temperature, and pain
Special sensory nerves
**Carry sensations such as smell, sight, hearing, balance
Motor nerves:
**Axons of somatic motor neurons
Mixed nerves:
**Mixture of motor and sensory fibers

4. Summary of Function of Cranial Nerves
Figure 13.5b

5. Cranial Nerves
Four cranial nerves carry parasympathetic fibers that serve muscles and glands
Occulomotor (III)
Facial (VII)
Glossopharyngeal (IX)
Vagus (X)

6. Cranial Nerves Cranial Nerves
The 12 cranial nerve groups are identified by:
Primary function
Origin
Pathway
Destination

7. Cranial Nerves Olfactory Nerves (I) Primary function: Origin:
Special sensory (smell)
Origin:
Receptors of olfactory epithelium

8. Cranial Nerves Olfactory Nerves (I) Pathway:
Olfactory foramina in cribriform plate of ethmoid bone
Destination:
Olfactory bulbs
To the olfactory tract

9. Cranial Nerve I - Olfactory Nerve
Assesment
Have patient smell different items
Damage to the ethmoid bone
Can cause anosmia
Loss of smell

10. Cranial Nerves Optic Nerves (II) Primary function:
Special sensory (vision)
Origin:
Retina of eyes

11. Cranial Nerves
Optic Nerves (II)
Pathway:
Optic Canal of sphenoid bone

12. Cranial Nerves Optic Nerves (II) Destination:
Diencephalon via optic chiasm
Optic tracts
Leading to lateral geniculate nuclei
Olfactory Lobe

13. Cranial Nerve II - Optic Nerve
Assessment
Test visual Acuity one eye at a time
Snellen eye chart
Test peripheral vision one eye at a time
Cover one eye and have the patient look at your nose.
Move your finger to check superior and inferior fields
Damage to the orbits or diseases in the nervous system can cause a loss of vision.
Anopia
Ipsilateral blindness due to sensory loss in the nerve

14. Cranial Nerves Oculomotor Nerves (III) Primary function:
Motor (eye movements)
Controls four of six eye-movement muscles
Origin:
Midbrain
Pathway:
Superior orbital fissures of sphenoid

15. Cranial Nerves Oculomotor Nerves (III) Destination: Somatic motor
Superior, inferior, and medial rectus muscles
Inferior oblique muscle
Levator palpebrae superioris muscle

16. Cranial Nerves Oculomotor Nerves (III) Visceral motor
Parasympathetic Function
Ciliary ganglion

17. Cranial Nerves Oculomotor Nerves (III) Destination:
Visceral motor (Parasympathetic)
Intrinsic eye muscles
Cilliary Muscle
**Accommodation
of the lens
Circular Muscles
**Constriction of iris
Radial Muscles
**Dilation of iris

18. Cranial Nerve III - Oculomotor
Assessment
- To test the patients pupils
*Use a penlight and mm ruler
- Check to see where eyelid falls on the pupil
Damages
*Causes Ptosis
– Drooping of eyelid
*Causes diplopia
– Double vision
*Trouble with eye movements

19. Cranial Nerves The Trochlear Nerves (IV) Primary function:
Motor (eye movements)
Origin:
Midbrain

20. Cranial Nerves The Trochlear Nerves (IV) Pathway: Destination:
Superior orbital fissure of sphenoid
Destination:
Superior oblique muscle

21. Cranial Nerve IV - Trochlear Nerve
Assessment
-Have patient follow your
finger while moving it to the
nose
Damages
*Causes
 Diplopia
 Paralysis
 Strabismus
*Lazy Eye

22. Cranial Nerves The Trigeminal Nerves (V) Primary function: Mixed Nerve
Sensory
Functions in touch, pain, & temperature receptors of the face
Motor
Innervates the muscles of mastication

23. Cranial Nerves The Trigeminal Nerves (V) Largest cranial nerves
With three major branches
Ophthalmic
Maxillary
Mandibular

24. Cranial Nerves The Trigeminal Nerves (V) Sensory Innervation
Semilunar ganglion
Contains cell bodies of sensory neurons

25. Cranial Nerves The Trigeminal Nerves (V) Ophthalmic Branch (V1)
Sensory innervation to:
Orbital structures
Nasal cavity
Skin of forehead
Upper eyelid
Eyebrow
Part of nose

26. Cranial Nerves The Trigeminal Nerves (V) Pathway:
Ophthalmic Branch (V1)
Superior Orbital Fissure

27. Cranial Nerves Maxillary Branch (V2) The Trigeminal Nerves (V) Origin:
Sensory innervation to
Lower eyelid
Upper
Lip
Gums
Teeth
Cheek and nose
Palate and part of pharynx

28. Cranial Nerves The Trigeminal Nerves (V) Pathway:
Maxillary branch (V2)
Foramen Rotundum

29. Cranial Nerves The Trigeminal Nerves (V) Mandibular Branch (V3)
Sensory
innervation to:
Lower
Gums
Teeth
Lips
Palate
Part of tongue
Lingual Nerve

30. Cranial Nerves The Trigeminal Nerves (V) Origin:
Mandibular branch (V3)
Motor innervation From
Motor nuclei of pons

31. Cranial Nerves The Trigeminal Nerves (V) Destination:
Motor nerves of Mandibular Branch
Muscles of mastication
Chewing

32. Cranial Nerves The Trigeminal Nerves (V) Pathway: Mandibular branch
Foramen Ovale

33. Cranial Nerve V - Trigeminal
Assessment
*To test for pain, touch & tempersture
-Safety pin & hot and cold objects
*Corneal reflex
- Cotton wisk
*To test motor function
-Clench teeth and move jaw
side to side

34. Cranial Nerve V - Trigeminal
Damages
*Cause problems in chewing
*Loss of sensations of pain and
temperature
*Tic Douloureux
 Trigeminal Neuralgia
*Severe pain from damage
of maxillary and
mandibular nerves

35. Cranial Nerves The Abducens Nerves (VI) Primary function: Origin:
Motor (eye movements)
Origin:
Pons

36. Cranial Nerves The Abducens Nerves (VI) Pathway:
Superior orbital fissures of sphenoid
Destination:
Lateral rectus muscle
Moves eye laterally

37. Cranial Nerve VI - Abducens
Assessment
Make a big x in the air and draw a
line through it.
**Observe for twitching or
nystagmus
Damages
*Cannot move eyeball laterally
*Nystagmus – “Dancing Eyes”

38. Cranial Nerves Mixed The Facial Nerves (VII) Sensory Motor Origin:
Taste receptors on anterior 2/3 of tongue
Destination:
Sensory nuclei of pons

39. Cranial Nerves The Facial Nerves (VII) Sensory Innervation
Geniculate Ganglion
Contains cell bodies of sensory neurons

40. Cranial Nerves Origin: Motor Motor nuclei of pons Destination
The Facial Nerves (VII)
Origin:
Motor
Motor nuclei of pons
Destination
Somatic Motor
Muscles of facial expression

41. Cranial Nerves Somatic Motor Facial nerve branches Temporal Zygomatic
Buccal
Mandibular
Cervical branches

42. Cranial Nerves The Facial Nerves (VII) Destination Visceral motor
Parasympathetic Function
Pterygopalatine Ganglion
 Lacrimal gland
 Mucous Glands
Submandibular Ganglion
Submandibular Glands
Sublingual Glands

43. SUBLINGUAL
SUBMANDIBULAR

44. Cranial Nerves The Facial Nerves (VII) Pathway:
Internal acoustic meatus to facial canals
Then through the stylomastoid foramina

45. Cranial Nerve VII - Facial Nerve
Assessment
-- To test for taste
**Place sugar(sweet) salt, vinegar(sour) & quinine(bitter)
on anterior 2/3 of tounge
-- To test for tearing
**Place ammonia near the eyes
-- To test for facial symmetry
**Have patient close eyes, smile, whistle and blow

46. Cranial Nerve VII - Facial Nerve
Damages
*Shingles
* Lyme disease
* Loss of taste
* Decreased saliva
* Bell’s Palsy.

47. Cranial Nerves The Vestibulocochlear Nerves (VIII) Primary function:
Special sensory
Vestibular branch
Balance and equilibrium
Originates at receptors of vestibule (balance)
Connects to vestibular nuclei of pons and medulla oblongata

48. Cranial Nerves The Vestibulocochlear Nerves (VIII) Primary function:
Special sensory
Cochlear branch
Hearing
Originates at sensors of cochlea (hearing)
Connects with cochlear nuclei of pons and medulla oblongata

49. Cranial Nerves The Vestibulocochlear Nerves (VIII) Origin: Pathway:
Receptors of inner ear
Pathway:
Internal acoustic meatus of temporal bones

50. Cranial Nerve VIII - Vestibulocochlear
Assessment
**Tuning Fork
Damages
Vertigo
 Rotating
Ataxia
 Lack of coordination
Tinnitus
 Ringing of ears

51. *From motor nuclei of medulla oblongata
Cranial Nerves
The Glossopharyngeal Nerves (IX)
Primary function:
Mixed to head and neck
Origins:
Motor
*From motor nuclei of medulla oblongata
Sensory
Posterior 1/3 of tongue
Part of pharynx and palate
Carotid arteries

52. Cranial Nerves Superior and inferior ganglion
Sensory neurons of tongue and pharynx
FIGURE 14-25

53. Cranial Nerves The Glossopharyngeal Nerves (IX) Pathway:
Jugular foramina
Between occipital and temporal bones

54. Cranial Nerves The Glossopharyngeal Nerves (IX) Destination: Sensory
Sensory nuclei of medulla oblongata
Somatic motor
Nerves involved in swallowing

55. Cranial Nerves The Glossopharyngeal Nerves (IX) Destination:
Visceral motor
Parasympathetic Function
Otic Ganglion
Parotid salivary gland

56. Cranial Nerve - IX Glossophary-ngeal
Assessment
Test for taste on posterior 2/3
Test position of uvula
Test swallowing and gag reflex
Damages
Difficulty in
Swallowing
Digestion
Loss of taste
Loss of sensation in throat
Reduced saliva production

57. Cranial Nerves The Vagus Nerves (X) “The Vagabond”
The only cranial nerve that extends beyond the head and neck
Primary function:
Mixed
90% of parasympathetic function
Thorax and abdomen

58. Cranial Nerves The Vagus Nerves (X) Origins: Sensory Part of pharynx
Auricle and external acoustic meatus
Diaphragm
Visceral organs of thoracic and abdominopelvic cavities
Motor
Motor nuclei in medulla oblongata

59. Cranial Nerves The Vagus Nerves (X) Pathway: Jugular foramina
Between occipital and temporal bones

60. Cranial Nerves Sensory Neurons located in Superior Ganglion
Jugular ganglion
Inferior Ganglion
Nodose ganglion

61. Cranial Nerves The Vagus Nerves (X) Destination: Sensory
Sensory nuclei and autonomic centers of medulla oblongata
Visceral motor
Parasympathetic
Muscles of the palate and pharynx
Muscles of the digestive, respiratory, and cardiovascular systems in thoracic and abdominal cavities

62. Cranial Nerve X - Vagus Assessment **Same as IX Damages
Loss of sensations to organs
Interfere with swallowing, digestion and vocal cords
Increase blood pressure

63. Cranial Nerves The Accessory Nerves (XI) Primary function: Origin:
Motor to muscles of neck and upper back
Origin:
Motor nuclei of spinal cord and medulla oblongata

64. Cranial Nerves Accessory Nerve Structures Spinal root
Motor fibers that originate in anterior gray horns of first five cervical segments of spinal cord
Cranial root
Motor fibers that originate in medulla oblongata

65. Cranial Nerves The Accessory Nerves (XI) Pathway:
Jugular foramina between occipital and temporal bones

66. Cranial Nerves The Accessory Nerves (XI) Destination: Internal branch
Voluntary muscles of palate, pharynx, and larynx
Figure 14-27

67. Cranial Nerves The Accessory Nerves (XI) Destination: External branch
Sternocleidomastoid and trapezius muscles

68. Cranial Nerve XI - Accessory
Assessment
Have patient rotate head
Have patient cough
Damages
Ipsilateral paralysis of sternocleidimastoid and trapezius
So you can’t raise your shoulders or turn your head
Difficulty in swallowing

69. Cranial Nerves The Hypoglossal Nerves (XII) Primary function: Origin:
Motor (tongue movements)
Origin:
Motor nuclei of medulla oblongata

70. Cranial Nerves The Hypoglossal Nerves (XII) Pathway: Destination:
Hypoglossal canals of occipital bone
Destination:
Muscles of tongue

71. Cranial Nerve XII - Hypoglossal
Assessment
**Have patient protrude and retract
tongue
Damages
Atrophy of ipsilateral tongue
Difficulty
Swallowing
Chewing
Speaking

72. 72

73. 73

74. Cranial Reflexes Cranial Reflexes
Monosynaptic and polysynaptic reflex arcs
Involve sensory and motor fibers of cranial nerves
Clinically useful to check cranial nerve for brain damage

75. 75

76. CEREBRUM - I - Olfactory –smell l - II - Optic - vision
BRAINSTEM
MIDBRAIN
III - Oculomoter - movement of eye
IV - Trochlear – movement of eye
PONS
V - Trigeminal – chewing, touch, pain & temperature receptors
VI - Abducens – movement of eyeball
VII - Facial – facial expressions, tears, saliva & taste
VIII - Vestibulocochlear (vestibular branch only). - equilibrium
Medulla Oblongata
VIII – Vestibulocohlear – hearing & equilibrium
IX - Glossopharyngeal – swallowing, taste, saliva production, blood pressure and monitor breathing
X - Vagus – swallowing, coughing, voice, blood pressure, monitor breathing, control digestive secretions & organs of
heart, stomachand G, I tract
XI - Accessory – swallowing, movement of head and shoulders
XII - Hypoglossal – swallowing, chewing & speaking