Cranial Nerves examination

1. Clinical Examination of
Cranial Nerves- I
Dr. Sai Sailesh Kumar G
Associate Professor
Department of Physiology
RDGMC

2. Cranial nerves
 There are 12 cranial nerves.
 Motor, sensory and mixed nerves.
 3rd to 12th nerves arise from brain stem and
innervates facial, cranial and cervical tissues.
 The 1st and 2nd nerves consist of central nervous
tissues.

3. Cranial nerves
Motor Sensory Mixed
Occulomotor Olfactory Trochlear
Optic Vestibulo-cochlear Trigeminal
Abducent Facial
Accessory Glossopharyngeal
Hypoglossal vagus

4. Olfactory Nerve
(First Cranial Nerve)

5. Olfactory Nerve
 Carries the sensation of smell
 So the this nerve is tested by various olfactory stimuli

6. Olfactory Nerve
 Make the subject to sit comfortably
 Instruct the subject to smell, identify and name the odor
 Instruct the subject to occlude his/her one nostril by hand
 Instruct the subject to close his eyes
 Make the subject to smell the test material
 Test each nostril separately and compare

7. Olfactory Nerve

8. Optic Nerve
(Second Cranial Nerve)

9. Optic Nerve
 Carries sensation of vision
 Examination of this nerve reveals intactness of the visual pathway,
field of vision and acuity of vision

10. Optic Nerve- field of vision
 Confrontation test.
 Ask the subject to sit on a stool comfortably in an erect position
 Sit on a stool infront of the subject in such a way that your eyes and
subject eyes remain at the same level and at a dostance of about 3 feet.
 Ask the subject to fix his gaze at the tip of your nose
 Ask the subject to close one of his eyes and close your opposite eye
 Move your finger midway between you and the subject to test the field of
vision of your quadrants. Bring your finger from the periphery of four
quadrants to the centre of the visual field and ask the subject to say yes
when he sees the finger.

11. Optic Nerve- Visual acuity
 Snellen’s chart. – distant vision
 Ensure that the snellen’s chart is well illuminated
 Make the subject to stand at a distance of 20 feet from the chart
 Perform the test without spectacles and with spectacles if he uses one
 Ask the subject to cover one eye with his cupped hand
 Ask the subject to read down the chart as far as he can
 Note the line and its distance to which the subject is able to read
comfortably
 Repeat the procedure with the other eye

12. Optic Nerve- Visual acuity
 Snellen’s chart – distant vision
 If the subject is unable to read the top letter, move the subject
towards the chart, until the subject can read the top letter
 Visual acuity is recorded according to the ratio
 V=d/D
 d- distance at which the subject reads the chart
 D-Distance at which letters should be read
 Record the observations

13. Optic Nerve- Visual acuity
 Jaegar’s chart – near vision
 Make the subject to sit comfortably in a well illuminated room
 Perform the test without spectacles and with spectacles if he uses one
 Ask the subject to cover one eye with his cupped hand
 Hold the chart at 35 cm distance or 14 inches from the eye
 Ask the subject to read from above downwards
 Note the smallest type of the letters that the subject can read comfortably
 Repeat the procedure with other eye
 Record the observations

14. Snellen’s chart – distant vision

15. Jaegar’s chart – near vision

16. Occulo motor Nerve,
Trochlear nerve and
Abducent cranial nerves
(Third, fourth and sixth Cranial Nerves)

17. III,IV and VI th cranial nerves
 Make the subject to sit comfortably
 Ask the subject to look at a distant object
 Observe for presence or absence of drooping of upper eyelids
 Observe for presence/ absence of squint

18. III,IV and VI th cranial nerves
 Diplopia
 Ask the subject to report if double vision occurs while following the
movements of your index finger
 Ask the subject to close his one eye with the hand
 Place your index finger in front of the subjects eye and then move
to extreme right, then to the left, then upwards and then
downwards
 Record the observation
 Repeat the procedure on other side and record the observation
 Repeat the procedure with subject’s both eyes open and record the
observation

19. III,IV and VI th cranial nerves
 Nystagmus
 Instruct the subject to look at the tip of your index finger and to
follow its movements
 Place your index finger in front of the subject’s eye, then move to
the extreme right, then to the left, then upwards and then
downwards.
 Observe presence or absence of nystagmus
 Repeat the procedure on the other side and record the
observation.

20. III,IV and VI th cranial nerves
 Ocular movements
 Instruct the subject to look at the tip of your index finger and follow
its movements with his eye
 Place your index finger in front of the subject’s eye, then move
your finger in medial, superior, lateral, inferior and oblique
directions
 Observe the ocular movements in all the directions
 Repeat the procedure on the other side and record the
observation.

21. III,IV and VI th cranial nerves
 Conjugate ocular movements
 Instruct the subject to look at the tip of your index finger and follow
its movements with his eye
 Place your index finger in front of and in between the subject’s
eyes, then move your finger in medial, superior, lateral, inferior and
oblique directions
 Observe and compare symmetry of ocular movements in both the
eyes.

22. III,IV and VI th cranial nerves
 Pupil
 Compare the size of the two pupils
 Observe the shape and contour of the two pupils

23. III,IV and VI th cranial nerves
 Mobility
 Reaction to light
 Light reflex

24. Pupillary reflexes
 Mediated by third cranial nerve
 Light reflex- direct, indirect
 Light reflex- direct
 Make the subject to sit comfortably
 Ask the subject to fix his gaze at a distant object
 Shine a bright light in one eye with the torch
 Observe immediate constriction of pupil in the same eye
 Elicit the light reflex on the other side and compare

25. Pupillary reflexes
 Mediated by third cranial nerve
 Light reflex- direct, indirect
 Light reflex- indirect
 Make the subject to sit comfortably
 Ask the subject to fix his gaze at a distant object
 Hold the cardboard on the forehead and bridge of the nose
 Shine a bright light in one eye with the torch
 Observe immediate constriction of pupil of both eyes
 Elicit the light reflex on the other side and compare

26. III,IV and VI th cranial nerves
 Mobility
 Reaction to accommodation
 Accommodation reflex

27. Pupillary reflexes
 Mediated by third cranial nerve
 Accommodation reflex
 Make the subject to sit comfortably
 Ask the subject to fix his gaze at a distant object
 Bring your index finger midway between and near the eyes of the
subject
 Ask the subject to look at the tip of the index finger
 Observe the constriction of pupil and convergence of eyes.

28. Trigeminal Nerve
(Fifth Cranial Nerve)

29. Sensory Functions
 Make the subject to sit comfortably
 Test for sensory modalities
 Fine touch
 Crude touch (Pressure touch)
 Tactile localization
 Two point discrimination (tactile discrimination)
 Vibration,
 Pain and temperature
 Overall skin and mucus membrane of face and compare both the
sides
 Elicit corneal and conjuctival reflexes

30. Corneal reflex
 Mediated by opthalmic division of trigeminal nerve
 Make the subject to sit comfortably
 Ask the subject to fix his gaze at a distant object or the ceiling
 Bring the cotton wisp from the side of the subject and touch the
lateral edge of the cornea at its conjunctival margin
 Observe that the subject blinks his eyes
 Elicit the corneal reflex on the other side and compare.

31. Corneal reflex

32. Conjunctival reflex
 Mediated by opthalmic division of trigeminal nerve
 Make the subject to sit comfortably
 Ask the subject to fix his gaze at a distant object or the ceiling
 Bring the cotton wisp from the side of the subject and touch the
bulbar part of conjunctiva
 Observe that the subject blinks his eyes
 Elicit the corneal reflex on the other side and compare.

33. Motor Functions
 Masseter
 Make the subject to sit comfortably
 Ask the subject to clench his teeth
 Palpate and compare the prominence of masseter muscles
 Temporalis
 Repeat the procedure for temporalis muscle
 Lateral pterygoid
 Ask the subject to open his mouth
 Observe the position of the jaw
 If there is paralysis of lateral pterygoid muscle, the jaw deviates
towards the paralyzed side.

34. THANK YOU