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Part II Nutrition Assessment, Consequences, and Implications TABLE 9.2 Testing Cranial Nerves

Cranial Nerve Number

1st 2nd 3rd Name Olfactory Optic Oculomotor Function Smell Detection of light

Eye movement upward, downward, and inward

Narrowing (constriction) or widening (dilation) of the pupil in response to changes in light

Raises the eyelids 4th 5th Trochlear Trigeminal Eye movement downward and inward Facial sensation Chewing Test

The faculty to smell is tested by asking the patient to detect articles with distinct odors.

The ability to detect light is tested by shining a bright light (as from a flashlight) into each pupil in a darkened room.

The ability to move each eye up and down is tested by instructing the patient to follow a target moved by the assessor.

The pupils’ response to light is checked by shining a bright light (as from a flashlight) into each pupil in a darkened room.

The upper eyelid is checked for drooping.

The ability to move each eye up and down is tested by instructing the patient to follow a target moved by the assessor.

Sensation in areas of the face is tested using a sharp object.

Strength and movement of muscles that control the jaw are tested by asking the person to clench the teeth and open the jaw against resistance.

6th 7th Abducens Facial Eye movement outward

Facial expression, taste in the front two-thirds of the tongue, production of saliva and tears, and control of a muscle involved in hearing

8th 9th 10th Auditory (vestibulocochlear) Glossopharyngeal Vagus

Swallowing, the gag reflex, and speech

Swallowing, the gag reflex, and speech

Hearing

The ability to move each eye outward beyond the midline is tested by asking the person to look to the side.

The capability to move the face is tested by asking the patient to smile, to open the mouth and show the teeth, and to close the eyes tightly.

Hearing is tested with a tuning fork or by rubbing fingers close to the patient’s ears.

Both the 9th and 10th cranial nerves control swallowing and the gag reflex. They are tested together.

The patient is asked to swallow and to say “aah” to check movement of the palate and uvula. To test the gag reflex, the back of the throat may be touched with a tongue blade.

11th 12th Accessory Hypoglossal Neck turning and shoulder shrugging Tongue movement

The patient is instructed to turn the head and to shrug the shoulders against resistance offered by the assessor.

The patient is instructed to stick out the tongue, which is observed for abnormality to one side or the other.

Source: From the Merck Manual: Consumer Version, edited by Robert Porter. Copyright 2009–2015 by Merck Sharp & Dohme Corp., a subsidiary of Merck & Co, Inc, Kenilworth, NJ. Available at www.merckmanuals.com/home/. Accessed April 9, 2015.