The three main cranial nerves discussed in the document are: 1) Trigeminal nerve (CN V) - supplies sensation to the face and motor function to the muscles of mastication. It is tested through facial sensation, corneal reflex, and jaw jerk reflex. 2) Facial nerve (CN VII) - supplies motor function to the muscles of facial expression and sensation from the ear and face. It is tested through facial muscles and taste. 3) Vagus nerve (CN X) - supplies motor function to the muscles of the throat and sensation from the throat, trachea, and abdomen. It is tested through palate elevation and gag reflex.

1. Cranial Nerves
By
Dr.usman haqqani

2. Olfactory nerve anatomy
Olfactory receptors in olf mucus membrane >> olf nerve fibers >>
Olf bulb>> olf tract

3. Olf tract >> medial and latral olf straie
Latral olf straie >> prim olf cortex(periamygdeloid and preperiform)
Medial olf straie>>mid line (ant commisure)>>opposite olf bulb

5. examination
• Test smell in each nostril with eyes closed.
• Coffee
• Vanilla
• Perfumed soap

6. Optic nerve
Retina >op nerve >chiasma > LGN (pulvinar thalamus) > op rad > PVC
….. LGN >sup colliculus >pretectal nucleus>LIGHT REFLEX

10. • Examination
– Acuity
– Colour
– Fields
– Reflexes
– Fundoscopy
ishihara color test
Snellen chart

11. Occulomotor nerve

15. supplies
• Innervation of eye muscles
• Superior rectus: moves eye upward
• Inferior rectus: moves eye downward
• Medial rectus: adducts eye (towards nose)
• Inferior oblique: moves eye medially and upward
• Levator palpebrae: elevates upper eyelid
• Constrictor pupillae: constricts pupil
• Ciliary muscles: control curvature of eye lens

16. examination
• Examination of light reflexes tests CN 2 and
CN3
– Pupil Light Reflex
– Swinging light reflex
– Accomodation reflex

17. Trochlear nerve

18. Trochlear nerve

21. • Innervates the superior oblique muscle of the eye
• Moves eye inward, down and laterally

22. Examination
• Extraocular Movements (CN III, IV, VI nerves are tested)

23. Trigeminal nerve

26. V1> sup orbital fissure V2>> foramen rotundum
V3>> Foramen ovale

29. • Sensory innervation to
• Face
• Scalp to vertex of head
• Conjunctiva of eye (covering of eye)
• Nasal sinus mucosal lining
• Lining of oral cavity
• Tongue
• Teeth
• External aspect of tympanic membrane
• Meninges of the anterior and middle cranial fossa

30. • Motor innervation of the
• Muscles of mastication (chewing)
• Tensor tympani muscle(adjusts tension on ear drum to
adjust for loud noises)
• Tensor veli palatini muscle(palate elevation)
• Mylohyoid muscle (moves hyoid bone)
• Anterior belly of digastric muscle

31. examination
• Facial Sensation
• Corneal Reflex
• Masseter
• Jerk Jaw Reflex

32. Abducent nerve

36. supply
• Innervates the lateral rectus muscle of the
eye
– Moves eye laterally (abducts eye towards the
ear)

37. Facial nerve

42. supply
• Motor innervation to
• Stapedius muscle (adjusts stapedius bone in response
to loud sounds)
• Posterior belly of digastric muscle
• Muscles of facial expression (buccinator, platysma,
occipital muscles)
• Innervation of taste
• from ant 2/3 of the tongue, hard and soft palate.

43. • Innervation for sensation from
• Skin behind ear
• Wall of ear canal
• External tympanic membrane
• Innervation of
• Lacrimal gland (tearing of the eye)
• Sublingual glands (salivation)
• Submandibular gland (salivation)
• Mucous membranes of nose

44. examination
• Facial Muscles
• Taste

45. Vestibulococlear nerve

49. supply
• Hearing (innervates the cochlea)
• Balance (innervates the semicircular
canals)

50. examination
• Hearing
• Positional Vertigo Test

51. Glossophryngeal and vagus nuclei

55. supply
• Innervates the parotid gland (salivation)
• Sensation from the carotid artery to control blood
pressure and fluid balance (carotid body and carotid
sinus innervation)
• sensation from the
• Posterior 1/3 of the tongue
• Skin of the external ear
• Inner surface of tympanic membrane (ear drum)
• Taste from the posterior 1/3 of the tongue

56. Vagus nerve

57. supply
• Motor innervation to the muscles of the
• throat (striated m.)
• tongue (striated m.)
• larynx (striated m.)
• tensor veli palatini (striated m.)
• abdominal organs (smooth m.)

58. • Sensation from the
• Throat
• Trachea (wind pipe)
• Esophagus
• Abdominal organs
• Chemical receptors near aorta
• Skin
• Back of the ear
• External ear canal External surface tympanic membrane
(ear drum)

59. examination
• Palate Elevation and Gag Reflex (CN IX, X)
– Ah test and gag reflex

60. Accesory and Hypoglossal nerve nuclei

62. Accessory

64. • Motor supply to sternocleidomastoid m.
and trapezius m. (turn head and shrug
shoulders)

65. examination
• Sternocleidomastoid and Trapezius Muscles (CN XI)

66. Hypoglossal nerve

68. examination
• Tongue Protrusion

69. Thank you