Cranial Nerves Flashcards
CN 1 - OLFACTORY NERVE (procedure/findings)
-Have client sit in a comfortable position at your eye level. Ask the client to clear the nose to remove any mucus. Close eyes, occlude one nostril, and identify a scented object. Repeat procedure for the other nostril
-Normal
Client correctly identifies scent presented to each nostril.Some older clients’ sense of smell may be decreased
-Deviations from normal
Inability to smell or identify the correct scent which is Neurogenic Anosmia. May indicate tract lesion frontal lobe tumor, congenital, nasal or sinus problems, nerve tissue injury, smoking, and use of cocaine
CN 2 - OPTIC (procedure/findings)
Use a snellen chart to assess vision in each eye. Ask the client to read a newspaper or magazine paragraph to assess near vision. Assess visual fields of each eye by confrontation. Use an ophthalmoscope to view the retina and optic disc of each eye
VISUAL ACUITY
Normal
Client has 20/20 vision OD and OS - (distance vision)
Deviations from normal
Difficulty reading snellen chart , Missing letters, Squinting
NEAR VISION
Normal
Reads print at 14 inches without difficulty until the patient is in the late 30s to the late 40s, reading is generally possible at a distance of 14 inches.
Deviations from normal
Reads print by holding closer than 14 inches or holds print farther away as in presbyopia, which occurs with aging.
VISUAL FIELDS
Normal
Normal peripheral vision
Deviations from normal
Loss of visual fields may be seen in retinal damage or detachment
Lesions of the optic nerve
Lesions of the parietal cortex
RETINA & OPTIC DISC by OPHTHALMOSCOPE
Normal
Optic disc - 1.5 mm
Round or slightly oval
Well-defined margins
Creamy pink with paler physiologic cup
Retina pink
Deviations from normal
Papilledema
Optic atrophy
CN 3,4, and 6 - OCULOMOTOR, TROCHLEAR, ABDUCENS (procedure/findings)
Inspect margins of the eyelids of each eye. Assess extraocular movements. Assess pupillary response to light (direct and indirect) and accommodation in both eyes
-Normal
Eyelid covers about 2 mm of the iris
Eyes move in a smooth, coordinated motion in all directions (6 cardinal fields)
Bilateral illuminated pupils constrict simultaneously
Pupil opposite the one illuminated constricts simultaneously
-Deviations from normal
Ptosis is seen with weak eye muscles: myasthenia gravis
Possible causes of abN eye movements:
cerebellar disorders
increased ICP
paralytic strabismus
Possible causes of pupil abnormalities:
Oculomotor nerve paralysis
Argyll robertson pupils
Narcotics abuse
CN 3 damage
Lesions of the sympathetic nervous system
PNS or CNS dysfunction
CN 5 lesion
CN 5 - TRIGEMINAL (procedure/findings)
Test motor function:
ask the client to clench the teeth while you palpate the temporal and masseter muscles for contraction
Normal
Temporal and masseter muscles contract bilaterally
Deviation from normal
Decreased contraction in one of both sides
Asymmetric strength in moving the jaw may be seen with lesion or injury of the 5th cranial nerve
Pain occurs with clenching of the teeth
Test sensory function:
tell the client “I am going to touch your forehead, cheeks, and chin with the sharp or dull side of the cotton tip applicator. Please close your eyes and tell me if you feel a sharp or dull sensation. Also tell me where you feel it”.
Vary the sharp and dull stimulus in the facial areas and compare sides. Repeat test for light touch with a wisp of cotton.
Normal
Correctly identifies sharp and dull stimuli and light touch to the forehead, cheeks, and chin
Deviation from normal
Inability to feel and correctly identify facial stimuli
Lesions of the trigeminal nerve
Lesions in the spinothalamic tract or posterior columns
Test corneal reflex:
ask the client to look away and up while you lightly touch the cornea with a fine wisp of cotton. Repeat on the other side.
Normal
Eyelids blink bilaterally
Deviation from normal
Absent corneal reflex
Lesions of the trigeminal nerve
Lesions of the motor part of CN 7 (facial)
CN 7 - FACIAL (procedure/findings)
Test motor function
Smile
Frown and wrinkle forehead
Show teeth
Puff out cheeks
Purse lips
Raise eyebrows
Close eyes tightly against resistance
Normal
Smiles, frowns, wrinkles forehead, shows teeth, puffs out cheeks, purses lips, raises eyebrows, and closes eyes against resistance
Movements are symmetric
Deviation from normal
Inability to close eyes, wrinkle forehead, or raise forehead along with paralysis of the lower part of the face on the affected side: bell’s palsy
Paralysis of the lower part of the face on the opposite side affected may be seen with a central lesion that affects the upper motor neuron: stroke
Test sensory function
Not routinely tested, if testing is indicated, however, touch the anterior two-thirds of the tongue with a moistened applicator dipped in salt, sugar, or lemon juice, ask the client to identify the flavor
If the client is unsuccessful, repeat the test using one or the other solutions
If needed, repeat the test using the remaining solution
Normal
Identifies correct flavor
Deviation from normal
Inability to identify correct flavor on anterior two-thirds of the tongue: impairment of cranial nerve 7
CN 8 - ACOUSTIC / VESTIBULOCOCHLEAR (procedure/findings)
Test the client’s hearing ability in each ear and perform the Weber and Rinne test to assess the cochlear (auditory) component of CN 8
Normal
Client hears whispered words from 1-2 ft.
Weber: vibration heard equally well in both ears
Rinne: AC > BC
Deviation from normal
Vibratory sound lateralizes to good ear in sensorineural loss
Air conduction is longer than bone conduction
ROMBERG TEST
Test the clients equilibrium/inner ear vestibular function
Ask the client to stand with feet together, arms at side, and eyes open, then with the eyes closed.
Stand close by in case the patient loses balance.
Put your arms around the patient without touching him/her to prevent fall.
Note patient’s ability to maintain balance
Normal
Client maintains position for 20 seconds without swaying or with minimal swaying
Maintains balance
Negative romberg
Deviations from normal
Clients moves feet apart to prevent falls or starts to fall from loss of balance: may indicate a vestibular disorder
Loss of balance:
Inner ear disorder
Cerebellar damage
Ingestion of intoxicants
CN 9, 10 - GLOSSOPHARYNGEAL, VAGUS (procedure/findings)
Test motor function:
Ask the client to open mouth wide and say “ah” while you use a tongue depressor on the client’s tongue
Normal
Uvula and soft palate rise bilaterally and symmetrically on phonation
Deviation from normal
soft palate does not rise
Bilateral lesions of cranial nerve X (vagus)
Unilateral rising of the soft palate and deviation of the uvula to the normal side
Unilateral lesion of cranial nerve X (vagus)
Test gag reflex
Touch the posterior pharynx with the tongue depressor
Normal
Gag reflex intact
Some normal clients may have a reduced or absent gag reflex
Deviation from normal
An absent gag reflex
Lesions of cranial nerve 9 (glossopharyngeal) or 10 (vagus)
Check ability to swallow
Giving the client a drink of water
Note the voice quality
Normal
Swallows without difficulty
No hoarseness noted
Deviation from normal
Dysphagia or hoarseness
Lesion of cranial nerve 9 or 10
Neurological disorder
CN 11 - SPINAL ACCESSORY (procedure/findings)
Ask the client to shrug the shoulders against resistance to assess the trapezius muscle
Normal
Symmetric
Strong contraction of the trapezius muscles
Deviation from normal
Asymmetric muscle contraction or drooping of the shoulder
Paralysis or muscle weakness due to neck injury or torticollis
Ask the client to turn the head against resistance, first to the right then to the left, to assess the sternocleidomastoid muscle
Normal
Strong contraction of sternocleidomastoid muscle on the side opposite the turned face
Deviations from normal
Atrophy with fasciculations may be seen with peripheral nerve disease
CN 12 - HYPOGLOSSAL (procedure/findings)
Assess strength and mobility of tongue. Ask the client to protrude tongue, move it to each side against the resistance of a tongue depressor, and then put it back in the mouth
Normal
Tongue movement is symmetric and smooth, and bilateral strength is apparent
Deviation from normal
Fasciculations and atrophy of the tongue: peripheral nerve disease
Deviation to the affected side: unilateral lesion
LEVEL OF CONSCIOUSNESS
Alert - follows commands in a timely fashion
Lethargic - appears drowsy, may drift off to sleep during examination
Stuporous - requires vigorous stimulation (shaking, shouting) for a response
Comatose - does not respond appropriately to either verbal or painful stimuli
GLASGOW COMA SCALE
Eye opening response
Spontaneous opening - 4
To verbal command - 3
To pain - 2
No response - 1
Most appropriate verbal response
Oriented - 5
Confused - 4
Inappropriate words - 3
Incoherent - 2
No response - 1
Most integral motor response (arm)
Obeys verbal commands - 6
Localized pain - 5
Withdraws from pain - 4
Flexion (decorticate rigidity) - 3
Extension (decerebrate rigidity) - 2
No response - 1
