By

HEMNATH RAJENDRAN

FIRST CRANIAL NERVE Olfactory nerve

• RESPONSIBLE FOR CARRYING SMELL SENSATIONS

• TESTING:

• ASK THE PATIENT TO close his eyes and SMELL DIFFERENT ODOURED SUBTANCES SUCH AS CAMPHOR,COFEE POWDER etc.,AND ASK WHETHER HE COULD DIFFERENTIATE THE ODOURS

SECOND CRANIAL NERVEOptic nerve

• CHECK THE VISUAL ACUITY BY USING SNELLEN CHART

• IF THE PATIENT USES SPECS ASK HIM TO USE IT WHILE READING THE CHART

• VISUAL FIELD TEST• Face the patient and ask him to see your

eyes bring your finger from periphery to center

• Ask at what point the subject can see your finger and make an imaginary visual field

SNELL’S CHART

EXAMINATION OF SECOND CRANIAL NERVE CONT….

• COLOUR VISION TEST

Use coloured papers of different colours and ask him to differentiate the colours . Use ishihara chart

Ishihara chart

• To check pupils

• Do light accomodation test

• Ask the patient to view distant object

And suddenly bring your finger near patient’s eye from the side and ask him to focus on your finger

Note the dialation of pupil and convergence of eye ball

• Light reflex

• Direct : direct light to fall on the person’s eye note the constriction of pupil

• Indirect reflex : constriction of pupil of the other eye when one is stimulated by the light rays

Examination of 3rd,4th 6th cranial nerves3rd- Oculomotor nerve4th-Trochlear nerve6th- Abducens nerve

• Involved in eye movements

• Ask wheather the person sees any double image this is the most important sign for defective eye movement

• Ask the patient to look up down and sidewards

• Ask the person to follow your finger ..moving your finger up and down,right,left

• Look out for nystagmus a repetitive drift of eye away from point of fixation followed by a corrective movement

• Look for ptosis : drooping of eyelids seen in 3rd nerve palsy

5th cranial nerve(Trigeminal nerve)

• Receives sensation from the face and innervates the muscles of mastication;

• TESTING

• Massester: ask the patient to clench the teeth palpate the muscle

• Pterygoid : ask to open the mouth the will deviate to side of lesion

• Test facial sensations

7th cranial nerve( FACIAL NERVE)

• Provides motor innervation to the muscles of facial expression, receives the special sense of taste from the anterior 2/3 of the tongue

TESTING OF 7th

• Ask the person to show teeth, smile, raise his eyebrow,

• Test the taste sensations

8th CRANIAL NERVEVestibulocochlear nerve

• Senses sound,

• EXAMINATION

• Bring watch near the patient’s ear ask wheather he could hear the tickling sound

• Perform rinne’s test and weber’s test

Rinne test

• The Rinne test is performed by placing a vibrating tuning fork (512 or 256 Hz) initially on the mastoid process until sound is no longer heard, the fork is then immediately placed just outside the ear. Normally, the sound is audible at the ear.

• Air conduction uses the apparatus of the ear (pinna, eardrum and ossicles) to amplify and direct the sound whereas bone conduction bypasses some or all of these and allows the sound to be transmitted directly to the inner ear albeit at a reduced volume, or via the bones of the skull to the opposite ear.

Weber test

• In the Weber test a vibrating tuning fork (either 256 or 512 Hz) is placed in the middle of the forehead,chin, head equidistant from the patient's ears. The patient is asked to report in which ear the sound is heard louder. In a normal patient, the sound is heard equally loud in both ears (no lateralization). However a patient with symmetrical hearing loss will have the same findings. Thus, there is diagnostic

utility only in asymmetric hearing losses.

9th AND 10th CRANIAL NERVE9th Glossopharyngeal nerve10th vagus nerve

• Ask the patient to open his mouth and say aah observe the movement of soft palate

• Gag reflex: pharyngeal reflex or gag reflex is a reflex contraction of the back of the throat evoked by touching the soft palate.

11th cranial nerve Accessory nerve

• Ask the patient to shrug his shoulder

• Test sternocleidomastoid muscle by rotating the head left and right

12th cranial nerve Hypoglossal nerve

• Ask the patient to open his mouth and look at the toungue

• Ask the patient to stick his toungue out ….. In case of lesion the toungue deviates to side of lesion