Examination of Cranial nerves VII to XII: Simple language and Video

Cranial Nerve I-VI examination 

VII Facial Nerve

Items needed for Facial Nerve Test 1.     Four sachets with 4 different items a.      Sugar powder b.     Salt powder c.     Sour (Vinegar) d.     Bitter (Grinded PCM/Metronidazole tablet) 2.     Gloves 3.     Guaze piece 4.     A bottle of drinkable water 5.     Four cards mentioning the words sweet, salty, sour and bitter in the language patient understands 1.     Ear buds/ Spatula

Confused with so many items. Here is a list of every thing you need to take for any CNS examination.

The motor function of the facial nerve is evaluated by looking for any gross features of weakness in the muscle of facial expression like deviation of mouth, loss of nasolabial fold or delayed blinking of the eyelid.

The patient is asked to wrinkle the forehead and look for symmetry.

The patient is asked to close her eyes, and close her eye against the examiners resistance which tends to pull upper and lower eyelids apart.

Ask the patient to smile and show their teeth.

Ask the patinet to whistle.

Ask the patient to blow their cheeks with air and hold it against the resistance given by the examiner.

The sensory function is evaluated by asking the patient to protude the tongue out and close the eyes. The anterior two third of the tongue is supplied by the chorda tympani  nerve and hence the four major tastes sweet, salt, sour and bitter to be evaluated. The solution containing each is prepared and using a new tongue blade or ear bud, the solution is applied over the tongue and the patient is asked to show the test in the cards given to him. After application of a solution, the patient is asked to thoroughly rinse the mouth with water.

VIII: Vestibulo Cochlear nerve

Items needed for Vestibulocochlear  Nerve Test 1.      Tuning Fork 256 Hz

The Cochlear function is assessed by using Tuning fork of 512 Hz is used to assess the hearing function.

Rennie Test: is performed by placing the vibrating tuning fork on the mastoid process and asking the patient to raise the hand if he stop hearing the sound. It assesses the Bone Conduction and the same tuning fork is brought and kept infront of the ear and ask if he still hears the sound.This measures air conduction(AC). If he hears the sound that AC>BC otherwise BC>AC. AC>BC is either normal or patient has sensorineural hearing loss. If BC>AC, it suggests conductive hearing loss.

Weber Test: Here the vibrating tuning fork is kept in the midline (glabella, vortex or even in between the incisors), the normal finding would be the sound heard in the midline. But if the sound is heard in one side then there is sensorineural hearing loss in the contralateral side and with conductive type of hearing loss loud sound is heard in affected side.

Some people fake hearing loss. Learn techniques to distinguish organic and non organic hearing loss. 

IX and X : Glossopharyngeal and Vagus Nerve

Items needed for Glossopharyngeal and Vagus Nerve Test 1.     Wooden spatula

Glossopharyngeal and vagus nerve supply the posterior oral cavity and oro pharynx and can be evaluated by observing the patient for any change in voice pattern especially hoarseness (Change in pitch seen in palatal paralysis) and history of aspiration or choking.

Ask the patient to open the mouth and   use a tongue depressor to visualize the tongue adeuately. Ask patient to pronounce “Ahh”. And look for differnce in palatal arch movement and deviation of uvula.

Inform patient that you are about to perform gag reflex and touch both the sides of palatal arch expecting for a gag to appear. The afferents are carried by the Glossopharynegeal nerve and efferent by motor component of glossopharyngeal and vagus nerve.

XI: Spinal accessory nerve

Test the sternoclaidomastoid muscle tone by asking the patient to turn head against the resistance applied over the left side of his cheek. Use the examiners right hand to apply resistance over the left cheek. Palpate the Right sided Sternoclaidomastoid for its tone and strength. And repeat the same for left side as well.

To check both the SCM simultaneously, place your hand in patients forehead and ask to bend forward. Now evaluate the SCM muscle for tone and strength.

XII: Hypoglossal Nerve

The Hypoglossal nerve supplies the muscle of the tongue and its function is examined by asking the patient to open the mouth and look for tongue deviation, wasting or any abnormal movements. The power and the tone is assessed by asking the patient to push the tongue against the buccal mucosa and palpating the tongue over the cheek to assess its strength.

Cranial Nerve I-VI examination