INTROCTION AND EXAMINATION OF CRANIAL NERVE

1. SUBMITTED TO SUBMITTED BY
Dr. APARNA SARKAR IRAM ANWAR
EXAMINATION OF
CRANIAL NERVE

2. Examination of Cranial Nerve

3. Cranial nerves
I. Olfactory
II. Optic
III. Occulomotor
IV. Trochlear
V. Trigeminal
VI. Abducent
VII. Facial
VIII. Auditory
IX. Glossopharyngeal
X. Vagus
XI. Spinal accessory
XII. Hypoglosseal

4. Pure sensory
Olfactory
Optic
Auditory
Pure motor
Trochlear
Abducent
Accessory
Hypoglosseal
Mixed nerves
Trigeminal
Facial
Glossopharyngeal
Vagus
Occulomotor
FUNCTIONAL TYPES

5. Cranial Nerve I: Olfactory

6. Function
Carries the sensation of smell from nasal
mucosa to olfactory bulb

7. Method of testing
Small bottles containing
essences of very familiar
odour are required
Coffee
Lemon
Chocolate
Asafetida etc

8. Common causes of anosmia
 Acute/chronic inflammatory nasal disease
 Heavy smoking
 Head injury
 Intra cranial tumour compressing the
olfactory bulb
 Atrophy of olfactory bulb
 Chronic meningeal inflammation
 Parkinson’s disease

9. Cranial Nerve II: Optic

10. Function
Carries the visual impulses from the retina to
the optic chiasma & in the optic tract to the
lateral geniculate body
The impulse acts as an afferent pathway for
the pupillary light reflex

11. Purpose of the test
To measure aquity of vision & determine if
any disease is due to local occular disease or
neural impairment
To chart the visual field

12. Common causes
Total unilateral loss of vision: optic nerve
lesion
Homonymous hemianopia: lesion between
optic tract to occipital cortex
Bitemporal hemianopia: lesion of optic
chiasma

13. Cranial nerve: III. Occulomotor ,
IV. Trochlear , VI. Abducent

14. Function
Controls the external occular muscles &
elevators of the lids
Also regulates the pupillary muscles

15. Method of testing
Observation
Presence & absence of ptosis & squint
Whether unilateral or bilateral
Constant or variable
Size, shape, equality & regularity of the pupils

16. Common causes of paralysis
 Pontine lesions
 Neoplasms
 Vascular accidents
 Demyelinating disease
 Meningeal inflammation
 Tumour of base of skull
 Increased intra cranial pressure
 Head injury
[Total paralysis of III, IV & VI nerve indicates a lesion in
cavernous sinus (carotid aneurism)]

17. Cranial Nerve V: Trigeminal

18. Function
Carries all forms of sensation from the face,
anterior scalp,eye & the anterior 3rd of the
tongue
Also supplies the muscles of mastication

19. Method of examination
Superficial sensory asst from mainly 6 areas
(mainly light touch & pain)
Forehead & upper part of the side of nose
(ophthalmic)
Malar & upper lip region (maxillary)
Chin & anterior part of tongue (mandibular)

20. Cranial Nerve VII: Facial

21. Function
Supplies the muscles of facial expression
including platysma & stapedius muscle
Secretomotor fibers to the lacrimal gland &
the salivary gland
Carries sensation of taste from anterior 2/3
of tongue & general sensation from external
acoustic meatus

22. Purpose of the test
To detect any unilateral or bilateral
weakness of facial muscles (UMN or LMN)
Detect impairment of taste

23. Common causes of facial paralysis
Neoplasm affecting thalamus: unilateral
emotional paralysis
Parkinsonism : bilateral emotional paralysis
CVA neoplasm, MND: bilateral UMN palsy
Bell’s palsy
GBS

24. Cranial Nerve VIII: Vestibulocochlear

25. Function
Carries the impulses of sound from the hair
cell of organ of corti to cochlear nucleus in
pons
Control balance through vestibular nerve

26. Common causes of deafness
Disease of external & middle ear &
Eustachian tube
Prolonged exposure to loud noise
Old age
Meningitis
Demyelinating disease
Deafness due to drugs

27. Cranial Nerve IX: Glossopharyngeal

28. Function
General Sensory: posterior 1/3 of tongue, tonsil, skin of external
ear, tympanic membrane & pharynx
Visceral Sensory: subconscious sensation from carotid body &
sinus
Visceral Motor: parasympathetic stimulation of parotid gland, &
controls blood vessels in carotid body
Special Sensory: carries taste from posterior 1/3 of tongue
Branchial Motor:
Supplies styolopharyngeus muscle

29. Cranial Nerve X: Vagus

30. Function
General Sensory: posterior meninges, concha, skin at back of ear,
external tympanic membrane, pharynx & larynx
Visceral Motor: parasympathetic stimulation to smooth muscle &
glands of pharynx, larynx; thoracic & abdominal viscera & cardiac
muscle
Visceral Sensory: from larynx, trachea, esophagus, & thoracic &
abdominal viscera, stretch receptors & chemoreceptors
Motor: superior, middle, inferior constrictors; levator palati,
salpingopharyngeus, palatopharyngeus, palatoglossus

31. Method of testing
 Notice the pitch & quality of voice, cough &
difficulty in swallowing saliva
 Ask the Pt to open his mouth wide after a few
movts ask to say “AH” while breathing out &
“UGH” while in
 The palate should move symmetrically upwards
& backwards, the uvula in mid line & two sides
of pharynx contract symmetrically

32. Common causes of lesion
Poliomyelitis
Syringobulbia
Posterior fossa tumor
Advanced parkinsonism
Myasthenia gravis
Enlarged cervical glands
Surgical operation of the neck

33. Cranial Nerve XI: Accessory

34. Function
Supplies sternocleidomastoid & trapezius muscles

35. Purpose of the test
To detect wasting & weakness, unilateral or
bilateral of the muscles

36. Cranial Nerve XII: Hypoglossal

37. Function
Control movts of the tongue, hyoid bone &
larynx during & after deglutition
Supplies 3 of 4 extrinsic muscles of
tongue & all intrinsic muscles of tongue

38. THANK YOU