Cranial Nerves

tongue movement and strength

CN XII, Hypoglossal nerve

difficulty swallowing, slurred speech.

CN XII, Hypoglossal nerve, significant findings,

Trochlear

CN IV

Vagus Nerve

CV X

Depress a tongue blade on posterior tongue, or stimulate posterior pharynx to elicit gag reflex. Note any hoarseness in voice. Check ability to swallow. Have patient say "ah". Observe for symmetric rise of uvula and soft palate.

Assessment of CN X, aka Vagus nerve

III, IV, VI.

Alterations in gaze may be related to impaired function of cranial nerves,

With eyes closed patient is asked to identify at least two familiar odors such as coffee,lemon, or tobacco. Avoid noxious odors such as ammonia. Each nostril is tested separately.

Assessment of CN I, aka Olfactory nerve

Examine each eye separately. Examiner stands in front of patient and tells the patient to focus on examiners nose; examiner moves fingers of left hand and then right into patient view from each of four fields.

Assessment of CN II, Optic Nerve, visual fields

Assess vision using a Snellen eye chart at 14", or ask patient to count examiner's fingers, or read large and small print of newspaper.Assess each eye separately. Perform opthalmoscopic examination.

Assessment of CN II, aka Optic nerve, visual acuity

Instruct the patient to fix both eyes on an object Shine the beam of a light directly into each pupil Note the size, shape, and reaction of the pupils.

Assessment of CN III, Oculomotor nerve, pupillary reaction

Test for upward eye movement; inspect for conjugate movements and nystagmus.

Assessment of CN IV, aka Trochlear nerve

Assess patient's ability to swallow and discriminate between salt and sugar on posterior third of tongue.

Assessment of CN IX, aka Glossopharyngeal nerve

While patient looks up, lightly touch a wisp of cotton against the temporal surface of each cornea. A blink and tearing are normal responses.

Assessment of CN V, aka Trigeminal nerve, corneal response

Have patient close eyes. Touch cotton to forehead, cheeks, and jaw. Sensitivity to superficial pain is tested by alternating sharp and dull ends of a broken tongue blade, and have patient report each. If responses incorrect, test temperature sensation, alternating test tubes of cold and hot water.

Assessment of CN V, aka Trigeminal nerve, facial sensation

Have patient clench and move jaw from side to side. Palpate masseter and temporal muscles, noting strength and equality.

Assessment of CN V, aka Trigeminal nerve, jaw movement

Test for lateral eye movement, inspect for conjugate movements.

Assessment of CN VI, aka Abducens nerve

Observe for symmetry while patient performs facial movements including smiles, whistles, elevates eyebrows, frowns, tightly closes eyelids against resistance, Observe face for flaccid paralysis, such as shallow nasolabial folds.

Assessment of CN VII, aka Facial nerve, facial movements

Have patient extend tongue. Test ability to discriminate between sugar and salt.

Assessment of CN VII, aka Facial nerve, tongue

Perform whisper or watch tick test. Test for lateralization, or Weber test. Test for air and bone conduction, or Rinne test. Assess balance with eyes open and then closed for about 20 seconds, or Romberg test.

Assessment of CN VIII, aka Acoustic nerve

While patient shrugs shoulders against resistance, palpate and note strength of trapezius muscles. As patient turns head against opposing pressure of examiner's hand, palpate and note strength of each sternocleidomastoid muscle.

Assessment of CN XI, aka Spinal Accessory nerve

While patient protrudes tongue, note any deviation or tremors. Test the strength of the tongue by having patient move the protruded tongue from side to side against a tongue depressor.

Assessment of CN XII, aka Hypoglossal nerve

Patient covers one eye while the examiner tests ocular movement. instruct patient to follow your finger without moving head. Examiner moves finger up, down, left, right (figure "H" motion). Note presence of nystagmus and ptosis.

Assessment of Ocular Movements, CN's III, IV, and VI

Hypoglossal

CN XII

Olfactory

CN I

smell

CN I, Olfactory Nerve

loss of sense of smell, anosmia.

CN I, Olfactory nerve, significant findings,

Optic

CN II

visual acuity and visual fields

CN II, Optic Nerve

visual field defects, hemianopias. decreased visual acuity or blindness.

CN II, Optic nerve, significant findings,

Oculomotor

CN III

pupillary reactions (pupillary light reflex and accommodation), eyelid elevation, and most extraocular eye movement (EOM) except for lateral movement.

CN III, Oculomotor Nerve

tongue movement and strength

CN XII, Hypoglossal Nerve controls

Dysconjugate gaze, gaze weakness or paralysis, double vision, dilated pupil with or without impaired pupillary reaction to light, inability to open the affected eyelid.

CN III, Oculomotor nerve, significant findings

moves the eye down and inward

CN IV, Trochlear Nerve

Dysconjugate gaze, gaze weakness or paralysis, double vision.

CN IV, Trochlear nerve, significant findings

Glossopharyngeal

CN IX

posterior third of tongue and pharynx, pharyngeal muscles, and swallowing.

CN IX, Glossopharyngeal Nerve

Difficulty swallowing, impaired taste

CN IX, Glossopharyngeal nerve, significant findings

control cough, gag, swallow, articulation, tongue movement, and phonation.

CN IX. Glossopharyngeal Nerve and (X) Vagus Nerve and (XII) Hypoglossal together

Trigeminal

CN V

sensation of face, corneal reflex, muscles of mastication (chewing);

CN V, Trigeminal Nerve

Impaired or absent corneal reflex, facial numbness, jaw weakness.

CN V, Trigeminal nerve, significant findings

Abducens

CN VI

lateral eye movement

CN VI, Abducens Nerve

Dysconjugate gaze, gaze weakness or paralysis, and double vision.

CN VI, Abducens nerve, significant findings

Facial

CN VII

supplies taste fibers to the anterior 2/3 of tongue; controls facial muscles, eyelid closure

CN VII, Facial Nerve

Facial weakness, inability to completely close eyelid, and impaired taste.

CN VII, Facial nerve, significant findings

Vestibulocochlear

CN VIII

Decreased hearing or deafness, impaired balance.

CN VIII, Acoustic nerve, significant findings

controls hearing and sense of balance (equilibrium)

CN VIII, Vestibulocochlear

controls autonomic function, as well as swallowing and gag reflex.

CN X, Vagus Nerve

weak or absent gag reflex, difficulty swallowing, aspiration, hoarseness, slurred speech.

CN X, Vagus nerve, significant findings,

Spinal Accessory

CN XI

trapezius and sternocleidomastoid muscles: movement of shoulder and head, shrugging of shoulders

CN XI, Spinal Accessory Nerve

weak or absent shoulder shrug, inability to turn head side to side.

CN XI, Spinal Accessory nerve, significant findings,

Instruct patient to open mouth and say "ahhh", assess for elevation of soft palate and that the uvula in the midline. Assess gag reflex by stimulating back of pharynx with tongue depressor Note any difficulties in articulation and/or speech and voice quality (hoarseness or nasal) Instruct patient to stick out tongue and move side to side while the examiner assesses for atrophy and deviation of the tongue to one side (normally the tongue is midline.

CN's IX, X, and XII are usually assessed together

III, IV, VI, XI, XII.

Cranial Nerves with only motor function

I, II, VIII.

Cranial Nerves with only sensory function

IX, X, XII.

Cough, gag, swallow, articulation, tongue movement, and phonation are functions of cranial nerves

V, VII, IX, X.

Cranial nerves with sensory and motor function

IX, X, XII.

Difficulty swallowing may be related to impaired function of cranial nerves

III, IV, VI.

Eye Movements are governed by cranial nerves

X, XII.

Slurred Speech may be related to impaired function of cranial nerves