Cranial Nerve Exam and Diseases Flashcards
Which nerve in CN 1?
Olfactory
Which nerve is CN 2?
Optic
Which nerve is CN 3?
Oculomotor
Which nerve is CN 4?
Trochlear
Which nerve is CN 5?
Trigeminal
Which nerve is CN 6?
Abducens
Which nerve is CN 7?
Facial
Which nerve is CN 8?
Vestibulocochlear
Which nerve is CN 9?
Glossopharyngeal
Which nerve is CN 10?
Vagus
Which nerve is CN 11?
Accessory
Which nerve is CN 12?
Hypoglossal
A lesion of this CN causes dysphonia, dysphagia, abnormal vocalizing, and megaesophagus
CN 10 (vagus)
Otitis media can cause deficits in which CN?
CN 9 (vestibulocochlear)
Vestibular signs like nystagmus will be seen with deficits in which CN?
CN 9 (vestibulocochlear)
Which CN provides motor innervation to the lateral rectus and part of the retractor bulbi muscles?
CN 6 (abducens)
A lesion in CN 6 (abducens) will cause what signs?
Medial strabismus (loss of fxn pulls globe medially)
What muscle closes the eyes?
Orbicularis oculi miuscle
Which CN closes the eyes?
CN 7 (facial)
Which CN opens the eyes?
CN 3 (oculomotor)
Which muscle opens the eyes?
Levator palpebrae superioris
Which muscles does CN 3 (oculomotor) provide sympathetic innervation to?
Levator palpebrae superioris, dorsal/medial/ventral rectus muscles
Which nerve do you assess with dazzle reflex?
Optic (CN 2)
Which nerves do you assess w/PLR?
Optic and oculomotor (CN 2 and 3)
What does CN3 (oculomotor) provide parasympathetic innervation to?
Iris sphincter muscles
Which CN innervates the dorsal oblique muscle of the eye?
CN 4 (trochlear)
What branch of the trigeminal nerve provides motor innervation to the muscles of mastication?
Mandibular branch
Which branch of the trigeminal nerve provides sensory innervation to the eyes, eyelid, and cornea?
Ophthalmic branch
Which branch of the trigeminal nerve provides sensory innervation to the face, pinnae, and nasal septum?
Maxillary branch
Which reflex assesses the trigeminal and facial nerves?
Palpebral
A lesion in CN 4 (trochlear) will cause what clinical sign?
Medial strabismus
Which portion of the tongue (taste) is innervated by the facial nerve?
Rostral 2/3
What are clinical sings of a lesion in the facial nerve (CN 7)?
Inability to blink, corneal ulceration, muzzle deviation
Which CN is assessed with a menace response?
CN 7 (facial)
Deficits in which CN can cause exposure keratitis due-to lacrimation defects?
CN 7 (facial)
Progressive muscle loss on the skull and atrophy of the masseter and temporalis muscle on the affected side indicate which neuropathy?
Trigeminal (CN 5) neuropathy
With a trigeminal neuropathy, are clinical signs uni- or bilateral?
Unilateral
How do you ddx trigeminal neuropathy from masticatory muscle myositis?
Myositis is bilateral
Autoimmune condition that leads to atrophy of the masseter and temporalis muscle bilaterally
Masticatory muscle myositis
Which CN mediates the sense of smell?
CN 1 (olfactory)
Which CN rarely has a primary neurologic problem?
CN 1 (olfactory)
Which CN carries visual signals from the retina to the occipital lobe of the brain?
CN 2 (optic)
How can you examine the optic nerve (CN 2)?
Menace, PLR, dazzle
Which CN provides motor to most of the extraocular muscles and for pupil constriction?
CN 3 (oculomotor)
How do you examine the oculomotor nerve (CN 3)
Physiologic nystagmus when turning head, PLR
Which CN provides motor function to the dorsal oblique extraocular muscle and rolls the globe medially?
CN 4 (trochlear)
How do you examine the trochlear nerve (CN 4)?
Check for dorsolateral rotation of the pupil
Which CN provides motor function to the muscles of mastication and sensory function to the eyelids, cornea, tongue, nasal mucosa, and mouth?
CN 5 (trigeminal)
Which CN provides motor function to the lateral rectus extraocular muscle and retractor bulbi?
CN 6 (abducens)
Which CN provides motor function to muscles of facial expression and sensory function to the medial pinna?
CN 7 (facial)
Which CN provides taste to the rostral tongue and parasympathetic innervation to the lacrimal and some salivary glands?
CN 7 (facial)
Which CN provides sensory input for hearing and head position?
CN 8 (vestibulocochlear)
Which CN provides innervation to the pharynx for swallowing, innervates some salivary glands, and provides taste to the caudal tongue?
CN 9 (glossopharyngeal)
How can you examine the glossopharyngeal nerve (CN 9)?
Elicit gag reflex and check for dysphagia
Which CN innervates the larynx, esophagus, and pharynx?
CN 10 (vagus)
Which CN provides parasympathetic innervation to the heart and viscera?
CN 10 (vagus)
Which CN innervates the cranial cervical muscles and is rarely a clinical problem?
CN 11 (accessory)
Which CN provides motor function to the tongue?
CN 12 (hypoglossal)
A syndrome seen in dogs w/peracute onset of a dropped jaw and inability to close the mouth
Idiopathic trigeminal neuritis
Dogs are normally alert and responsive w/o other sensory deficits and don’t have difficulty swallowing food
Idiopathic trigeminal neuritis
How do you treat idiopathic trigeminal neuritis?
Supportive care, fluids, hand feeding
How quickly can trigeminal neuritis dogs regain function?
1-2wk (normal again in 3-4wk)
Acute onset of inability to blink, drooping lip and ear, and drooling from one side of the mouth
Idiopathic facial nerve paralysis
How is facial sensation affected by facial nerve paralysis?
Normal
How is the eye affected by facial nerve paralysis?
Prone to exposure keratitis and corneal ulceration
What is the best treatment for idiopathic facial nerve paralysis?
Tear supplementation, immunosuppressants, supportive care
What is the prognosis for idiopathic facial nerve paralysis?
Fair (complete recovery doesn’t occur)
