PRESENTATION BY Dr. Muhammad Hamza Khawaja Family medicine LAHORE , Pakistan

1. CRANIAL NERVES
Dr. HAMZA KHAWAJA
FAMILY MEDICINE

2. INTRODUCTION
Cranial nerves are the nerves that emerge
directly from the brain (including the
brainstem).
There are twelve pairs.
Cranial nerves relay information between
the brain and parts of the body, primarily to
and from regions of the head and neck,
including the special senses of vision, taste,
smell, and hearing.

3. HISTORY
 The Graeco-Roman anatomist Galen (AD
129–210) named seven pairs of cranial
nerves.
 In 1664, English anatomist Sir Thomas
Willis suggested that there were actually 9
pairs of nerves.
 Finally, in 1778, German anatomist Samuel
Soemmering named the 12 pairs of nerves
that are generally accepted today.

4. LOCATION
 Olfactory nerves (I) and optic nerves
(II) emerge from the cerebrum.
 Remaining ten pairs arise from the
brainstem, which is the lower part of
the brain.

8. Exits of cranial nerves from the
skull.[10][13]
LocationNerve
cribriform plate Olfactory nerve (I)
optic foramen Optic nerve (II)
superior orbital fissure Oculomotor
(III)
Trochlear (IV)
Abducens (VI)
Trigeminal V1
(ophthalmic)
foramen rotundum Trigeminal V2
(maxillary)
foramen ovale Trigeminal V3
(mandibular)
stylomastoid foramen Facial nerve
(VII)
internal auditory canal
Vestibulocochlear (VIII)
jugular foramen Glossopharyngeal (IX)
Vagus (X)
Accessory (XI)
hypoglossal canalHypoglossal (XII)
LOCATION NERVE
CRIBRIFORM PLATE OLFACTORY NERVE (I)
OPTIC FORAMEN OPTIC NERVE (II)
SUPERIOR ORBITAL FISSURE  OCULOMOTOR (III)
 TROCHLEAR (IV)
 ABDUCENS (VI)
 TRIGEMINAL V1
 (OPHTHALMIC)
FORAMEN ROTUNDUM TRIGEMINAL V2
(MAXILLARY)
FORAMEN OVALE TRIGEMINAL V3
(MANDIBULAR)
STYLOMASTOID FORAMEN FACIAL NERVE (VII)
INTERNAL AUDITORY CANAL VESTIBULOCOCHLEAR (VIII)
JUGULAR FORAMEN  GLOSSOPHARYNGEAL (IX)
 VAGUS (X)
 ACCESSORY (XI)
HYPOGLOSSAL CANAL HYPOGLOSSAL (XII)

10. I. OLFACTORY NERVE
It is sensory nerve.
Carries impulses for sense of smell.
ORIGIN : olfactory epithelium
OPENING IN SKULL :
opens in cribriform plate of ethmoid
bone to receptors in roof of nasal cavity.

11. Attaches to cerebrum.
Lesion leads to bilateral anosmia can
be caused by disease of olfactory
mucous membrane, such as the
common cold .

13. OLFACTORY NERVE
EXAMINATION
• Ask patient to close one nostril and to
expirate to see if there is foreign body.
• Closing one nostril, ask patient to know the
smell on the other.
• Repeat for the other nostril.

14. II.OPTIC NERVE
It is sensory nerve.
It carry impulses for vision.
Origin : Back of eye ball/ retina of eye
.
Opening to skull :
Optic canal and from there it converges
to form optic chiasm.

15. Reflexes generated by this nerve are
light reflex by lateral geniculate body,
visual reflex & corneal reflex by
blinking of eyes.
Lesion leads to total blindness of one
eye, hemianopia(partial lesion of optic
chiasma on its lateral side).

17. OPTIC NERVE EXAMINATION
6 things to examine in optic nerve
• Visual acuity
• Visual field
• Color vision
• Pupillary reflex (2 is afferent, 3 is
efferent)
• Accomodation reflex (2 is afferent, 3 is
efferent)
• Ophthalmoscopic examination

18. III. OCULOMOTOR NERVE
It is motor nerve.
Functions :
1. raises the upper eyelid.
2. turn eye ball upward, downward &
medially.
3. constricts pupil.
4. accommodates the eye

19.  Origin : anterior surface of midbrain.
 Opening in skull : Superior orbital
fissure.
 Lesion leads to drooping of the upper
eyelid (ptosis) due to paralysis of
levator palpebrae superioris muscle.
 Conditions effecting oculomotor
nerve are diabetes, aneurysm, tumor,
trauma, inflammation& vascular
disease

21. IV. TROCHLEAR NERVE
It is motor nerve.
Function: Assisting in turning eyeball
downward and laterally
Origin : Posterior surface of the midbrain
& innervate the superior oblique muscle.
Opening to the Skull : Superior orbital
fissure.

22. Attaches to midbrain.
Lesion is due to aneurysm of internal
carotid artery & vascular lesion of dorsal
part of midbrain.
Patient complains of double vision on
looking downward.

24. VI. ABDUCENT NERVE
It is motor nerve
Function: Lateral rectus muscle turns
eyeball laterally
Origin : Anterior Surface of hindbrain
between pons and medulla
Opening to the Skull : Superior
orbital fissure

25. Fibers leave the inferior pons & enter
orbit via superior orbital fissure.
Patient can’t turn the eye laterally.
Lesions include damage due to head
injuries, cavernous sinus thrombosis or
aneurysm of internal carotid artery &
vascular lesions of pons.

27. V. TRIGEMINAL NERVE
It has three divisions as:
Ophthalmic division
Maxillary division
Mandibular division

29. V1.OPHTHALAMIC NERVE
It is sensory.
Function: cornea, skin of forehead, scalp,
eyelids,nose, also mucous membrane of
paranasal sinuses & nasal cavity.
Origin: Anterior aspect of pons.
Opening in skull: Superior orbital fissure.
Exit orbit through supra orbital foramen.
In lesion of this nerve cornea &
conjunctiva will be insensitive to touch.

30. V2.MAXILLARY NERVE
It is sensory nerve.
Function: skin of face over maxilla, teeth
of upper jaw, mucous membrane of nose ,
the maxillary sinus & palate.
Origin: Anterior aspect of pons.
Opening in skull: Foramen rotundum
Exit through infraorbital foramen.

31. V3. MANDIBULAR NERVE
• Component: a. Motor
• Function: Muscles of mastication,
Mylohyoid ,Anterior belly of
digastric, Tensor veli palatine, Tensor
tympani
• Opening to the Skull: Foramen ovale
• Origin: Anterior aspect of the pons

32. V3. MANDIBULAR NERVE
• Component: b. Sensory
• Function: Skin of cheek, Skin over
mandible and side of head, Teeth of
lower jaw , Mucous membrane of
mouth and anterior part of tongue
• Origin: Anterior aspect of the pons
• Opening to the Skull: Foramen ovale

33. TRIGEMINAL NERVE
EXAMINATION
1. Test for sensory functions
• Examine the 3 divisions of V nerve
bilaterally.
2. Test for motor function
• Muscle wasting (temporalis, masseter)
• Clench teeth to palpate masseter
• Open jaw and see deviation
• Open mouth against resistance

34. 3. Test for reflexes:
 Corneal reflexes (5 is afferent, 7 is
efferent).
 Jaw jerk

35. VII. FACIAL NERVE
It is mixed nerve.
Function:-
 Motor: Muscles of face & scalp, stapedius
muscle, posterior belly of digastric & stylohoid
muscle.
 Sensory: Taste from anterior 2/3rd of tongue,
from floor of mouth & palate.
 Secretomotor parasympathetic: submandibular
& sublingual salivary glands, the lacrimal gland
& glands of nose & palate.

36. Opening in the skull: internal
acoustic meatus, facial & stylomostoid
foramen.
Attaches to pons.
Effects of damage: inability to control
facial muscles; distorted sense of taste.

38. FASCIAL NERVE VII
EXAMINATION
• Taste sensation in anterior 2 /3 of
mouth
• Raise your eyebrows
• Close your eyes
• Nasolabial fold
• Blowing air wheezing
•Corneal reflex (5 is afferent, 7 is
efferent)

39. UMNL or LMNL in
patient with fascial nerve VII
• LESION A ?!!!
• weakness of
lower left half of
face
• Contralateral !
• UMNL
• LESION B ?!!
• complete
weakness of left
half of the face

40. BELL’S PALSY
Paralysis of facial muscles of affected side
Loss of taste sensation
Caused by herpes simplex virus.
Lower eyelids droops.
Corner of mouth sags.
Tears drips continuously & eye cannot be
completely closed.
Condition may disappear spontaneously
without treatment.

42. VIII.VESTIBULOCOCHLEAR
VESTIBULAR NERVE:-
• It is sensory nerve.
• Function: Position & movement of head.
• Opening in the skull: Internal acoustic meatus
COCHLEAR NERVE:-
• It is sensory nerve.
• Function: Organ of corti - hearing.
• Opening in the skull: internal acoustic meatus.

45. Damage to the vestibulocochlear nerve
may cause the following symptoms:
hearing loss
vertigo
false sense of motion
loss of equilibrium (in dark places)
nystagmus
motion sickness
gaze-evoked tinnitus.

46. IX. GLOSSOPHARYNGEAL
It is mixed nerve.
Function:-
• Motor: Stylopharyngeus muscle assists
swallowing.
• Secretomotor parasympathetic: parotid
salivary gland.
• Sensory: general sensation & taste from
posterior 1/3of tongue & pharynx, carotid
sinus & carotid body(chemoreceptor).

47. Opening in the skull: Jugular
foramen.
It attaches to medulla oblongata.
Clinical tests: gag reflex, swallowing,
and coughing
Effects of damage: difficulty
swallowing

48. X. VAGUS
It is mixed nerve.
Nick name: Wanderer
Function:-
Motor & sensory: Heart & great
thoracic blood vessels , larynx, trachea,
bronchi & lungs, alimentary tract from
pharynx to splenic flexure of colon,
liver, kidneys & pancreas.

49. Opening in the skull: Jugular
foramen.
Effects of damage:
hoarseness or loss of voice;dysphagia,
cardiovascular problems, digestive
problems, urinary incontinence,
deafness, palatal function, gag reflex,
spastic dysarthria.

51. GLOSSOPHARYNGEAL IX
AND VAGUS X NERVES
EXAMINATION
• Speach
• Swallow
• Cough
• Air escape from nose

52. XI. ACCESSORY
It is motor nerve.
Formed from cranial root emerging from
medulla & a spinal root arising from the
superior region of spinal cord.
Function: swallowing; head, neck, and
shoulder movements.
Opening in the skull: Jugular foramen.
Spinal root passes upward into cranium
via the foramen magnum.

53. Accessory nerve leaves the foramen
via the jugular foramen.
Clinical tests: rotate head and shrug
shoulders against resistance
Effects of damage:
impaired movement of head, neck,
and shoulders; paralysis of
sternocleidomastoid

55. ACCESSORY NERVE XI
EXAMINATION
• Inspect sternocleidomastoid muscle
(SCM) for wasting or hypertrophy and
palpate them to assess bulk.
• Stand behind patient and inspect
trapezius
• Ask patient to shrunk shoulders and
apply downward power to assess muscle
power.
• Assess SCM power by examining it
against resistance.

56. XII. HYPOGLOSSAL
It is motor nerve.
Function:- Muscles of tongue (except
palatoglossus) controlling its shape &
movement.
Opening in the skull: Hypoglossal canal
Innervates both extrinsic & intrinsic
muscles of tongue.

57. Clinical test: tongue function
Effects of damage: difficulty in speech
and swallowing; atrophy of tongue;
inability to stick out (protrude) tongue
Lesions occur from demyelinating
diseases & vascular accidents.

59. REFERENCES
 Standring, Susan; Borley, Neil R. (2008). "Overview of
cranial nerves and cranial nerve nuclei". Gray's anatomy:
the anatomical basis of clinical practice (40th ed.).
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443-06684-9.
 Board Review Series – Neuroanatomy, Fourth Edition,
Lippincott Williams & Wilkins, Maryland 2008, p. 177.
ISBN 978-0-7817-7245-7.
 Albert, Daniel (2012). Dorland's Illustrated Medical
Dictionary (32nd ed.). Philadelphia, PA: Saunders/Elsevier.
ISBN 978-1-4160-6257-8.

60.  Keith L. Moore; Anne M.R. Agur; Arthur F. Dalley (2010). Clinically
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 Mukherjee, Sudipta; Gowshami, Chandra; Salam, Abdus; Kuddus,
Ruhul; Farazi, Mohshin; Baksh, Jahid (2014-01-01). "A case with
unilateral hypoglossal nerve injury in branchial cyst surgery".
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