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.
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 .
12.
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).
16.
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
20.
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.
23.
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.
26.
27. V. TRIGEMINAL NERVE
It has three divisions as:
Ophthalmic division
Maxillary division
Mandibular division
28.
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.
37.
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.
41.
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.
43.
44.
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.
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
54.
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.
58.
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.).
[Edinburgh]: Churchill Livingstone/Elsevier. ISBN 978-0-
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
oriented anatomy (6th ed.). Philadelphia: Lippincott Williams &
Wilkins, Wolters Kluwer. pp. 1055–1082. ISBN 978-1-60547-652-0.
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".
Journal of Brachial Plexus and Peripheral Nerve Injury. 7 (1): 2.
doi:10.1186/1749-7221-7-2. PMC 3395866. PMID 22296879.
Anthony S. Fauci; T. R. Harrison; et al., eds. (2008). Harrison's
principles of internal medicine (17th ed.). New York [etc.]: McGraw-
Hill Medical. pp. 2583–2587. ISBN 978-0-07-147693-5.
Talley, Nicholas J.; O'Connor, Simon (2018). "Chapter 32. The
neurological examination: general signs and the cranial nerves".
Clinical examination (8th ed.). Chatswood: Elsevier. pp. 500–539.
ISBN 9780729542869.