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1210 Cranial Nerve Deficits

Cranial Nerve Deficits
VetBooks.ir Nerve Clinical Signs Clinical Tests Normal Response Abnormal Response

I. Olfactory Hyposmia or anosmia Smell of food or nonirritating, Interest in food; sniff, recoil, No response
volatile substance or nose lick with volatile
substance
II. Optic Visual impairment and hesitancy in moving 1. Obstacle test 1. Avoidance of obstacle 1. Bumping objects
2. Visual placing reaction 2. Visual placement of 2-4. No response
3. Menace reaction limbs
4. Following movement test 3. Eye blink
4. Eyes following objects
III. Oculomotor Ventrolateral strabismus 1. Ocular movement in 1. Normal ocular excursion 1. Impaired movements of
horizontal and vertical affected eye
planes
Paralysis of upper eyelid (ptosis), mydriasis 2. Point source of light in each 2. Direct and consensual 2. On affected side, direct
eye pupillary light reflexes pupillary reflex absent,
consensual reflex present;
on normal side, direct
pupillary reflex present,
consensual reflex absent
Sympathetic control of Constricted pupil (miosis), enophthalmos,
pupillary function prolapse of third eyelid, ptosis of upper lid
IV. Trochlear Usually not noted
V. Trigeminal (motor Atrophy of masticatory muscles 1. Jaw tone 1. Resistance to opening 1. Lack of resistance
and sensory) Inability to close mouth 2. Palpate and observe jaws 2. Atrophy, hypotonia
masticatory muscles 2. Normal muscle contour 3-5. No response
3. Palpebral reflex and resilience 6. Intense discomfort
4. Corneal reflex 3. Eye blink
5. Probe nasal mucosa 4. Eye blink and globe
6. Touch face retraction
5. Recoil
6. No reaction
VI. Abducent Medial strabismus Ocular movements in horizontal Normal ocular excursion Impaired lateral movement of
plane affected eye
VII. Facial Asymmetry of facial expression 1. Palpebral reflex 1-3. Eye blink 1-4. No response
Inability to close eyelids 2. Corneal reflex 4. Ear flick
Lip commissure paralysis 3. Menace reaction
Ear paralysis 4. Tickle ear
VIII. Vestibulocochlear Nystagmus, head tilt, circling 1. Ocular movements in 1-2. Normal physiologic 1-3. No response,
Vestibular Falling and rolling horizontal and vertical nystagmus ventrolateral strabismus
planes 3. Normal righting on dorsal extension of
2. Caloric and rotatory test head
3. Righting reactions
Cochlear Deafness Hand clap Startle reaction, blink, ear No response
contraction
IX. Glossopharyngeal Dysphagia Gag reflex Swallowing response No response
X. Vagus Dysphagia 1. Gag reflex 1. Swallow 1-3. No response
Abnormal vocalizing 2. Laryngeal reflex 2. Cough
Inspiratory dyspnea 3. Oculocardiac reflex 3. Bradycardia
Megaesophagus
XI. Spinal accessory Usually not noted
XII. Hypoglossal Deviation of tongue 1. Tongue stretch 1. Retraction 1-2. No response
2. Nose rub 2. Lick response
With permission from Braund KG: Clinical syndromes in veterinary neurology, St. Louis, 1994, Mosby.

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