Cranial Nerves

____________ impairment of the CN I: Olfactory Nerve that is rarely noticeable because of contralateral nostril compensating for the loss of smell (anosmia)

____________ impairment of the CN I: Olfactory Nerve that is rarely noticeable because of contralateral nostril compensating for the loss of smell (anosmia)

Unilateral

___________ impairment of CN I: Olfactory Nerve in which the patient’s first complaint is the loss of taste, due to contribution of smell to the detection of flavor.

Bilateral

A lesion to the optic nerve results in…

Loss of some of the visual eye (eye of affected nerve).

When you close the unaffected eye, what do you see in the eye with the CN II: Optic nerve lesion?

Nothing. There is no info from the affected/injured eye.

A lesion to the optic chaism results in …

Tunnel Vision, loss of nasal retina in both visual eye fields

A lesion to the optic tract or optic radiation results in …

Loss of the entire visual field for the contralateral eye

Optic Neuritis

Inflammatory demyelinating condition of the CN II: Optic Nerve

Patients with Optic Neuritis may be diagnosed with Multiple Sclerosis. What is the primary sign?

Blurry vision or temporary blindness

A lesion to CN III: Oculomotor after it has exited the brainstem affects the ____________ eye, resulting in the eye deviating ___________ and __________.

Ipsilateral; laterally and inferiorly. Lateral Rectus is unopposed.

* remember: Down and Out

The eye will move in the direction of the _________ muscle when there is an affected eye muscle

Strong

With a CN III: Oculomotor nerve, the ________ muscles causes the pupil to ______

Ciliary; constrict

What is the most common patient presentation for a CN III: Oculomotor lesion?

Diplopia

What is the most common patient complaint for a CN III: Oculomotor lesion?

Dizziness

Damage to the CN IV: Trochlear nuclei results in

Contralateral superior oblique palsy

With contralateral superior oblique palsy, the contralateral eye deviates ___ and ____ due to an unopposed inferior oblique.

Up and Out

Damage to CN IV: Trochlear after it has left the brainstem results in ____________ superior oblique palsy. The eye deviates _______ and ___.

Ipsilateral; Down and in

With a lesion to CN IV: Trochlear, the head may tilt _______ from the side of paralysis to help ______ the visual fields

Away; align

What is the most common patient presentation with a lesion to the CN IV: Trochlear?

Diplopia, when looking down and in

With a lesion to CN IV: Trochlear, patients may present with ____________.

Dizziness

With a CN V: Trigeminal lesion, there is impaired sensation to the ____________ side of the face

Ipsilateral

A lesion to CN V: Trigeminal, can result in loss of motor to the IPSILATERAL __________ of _______________.

Muscles of Mastication

What reflex may be affected by a lesion to CN V: Trigeminal?

Corneal reflex

Trigeminal Neuralgia

• Brief episodes of severe pain

• Most common in the Maxillary (V2) and Mandibular (V3) distribution

Damage to CN VI: Abducens nuclei results in ipsilateral ___________ ________ palsy. The ipsilateral eye will deviate __________.

Lateral Rectus; medially

Most common patient complaint of a lesion to CN VI: Abducen

Diplopia

With an UMN lesion of CN VII: Facial, there is a loss of motor to the ______________ lower face.

Contralateral

Can a patient with an UMN lesion to CN VII: Facial wrinkle their forehead?

Yes, because of bilateral control.

With an LMN lesion of CN VII: Facial, there is a loss of motor to the ______________ side of face.

Ipsilateral

With an LMN lesion of CN VII: Facial, which reflex is affected?

Corneal blink reflex

A lesion to CN VIII: Vestibulocochlear results in

• Unilateral hearing loss

  • Sensorineural hearing loss

  • Conductive hearing loss

Your patient complains of hearing loss. You take a tuning fork, strike it, and place it on the patient's left mastoid process while it is vibrating. When the patient says they can no longer hear the sound you quickly move the tuning fork next to the left ear. The patient says that they do not hear anything. The patient has ___________ hearing loss.

Conductive

With a lesion to CN IX: Glossopharyngeal, what are the impairments?

• Impaired sensation to the posterior 1/3 tongue, pharynx, and palate - impaired taste

• Difficulty swallowing (ipsilateral stylopharyngeus)

  • Impaired gag reflex

A CN IX: Glossopharyngeal lesion is more likely to be _________ lesion

Central

POTS is common with a lesion to what nerve?

CN X: Vagus

What is Postural Orthostatic Tachycardia Syndrome (POTS)?

Abnormal blood pressure and heart rate response to activity, positioning, and even rest

There is a lesion to Cn X: Vagus. What are the possible impairments?

• POTS

• Vasovagal Syncope

• Digestive disorders (gut-brain axis)

___________ weakness with a shoulder shrug is a sign of impairment to CN XI: Spinal Accessory.

Ipsilateral

What are the possible impairments you’d expect for a lesion to CN XI: Spinal Accessory?

• Ipsilateral weakness with shoulder shrug

• Weakness of head turn AWAY from lesion

An UMN lesion to what nerve results in contralateral tongue weakness

CN XII: Hypoglossal

A LMN lesion of CN XII: Hypoglossal results in ___________ tongue weakness.

Ipsilateral

With a CN XII: Hypoglossal lesion, the tongue with deviate ________ the weakness

Toward

Dysarthria

Tongue weakness

Which CN is responsible for the sense of smell?

CN I: Olfactory

Which CN is responsible for the vision?

CN II: Optic

Which CN is responsible for lifting the eyelid, and muscle function to the extraocular muscles of the eye (except abduction and rotation), and pupil constriction?

CN III: Oculomotor

Loss of innervation to levator palpebrae causes what?

Ptosis (droopy eyelid)

Loss of function to ciliary muscles causes what?

Dilated pupil

Which CN and muscle is responsible for pulling the eye inferiorly and medially?

CN IV: Trochlear and the Superior Oblique muscle

What is the sensory function of CN V: Trigeminal

Sensory to the face & anterior 2/3 of tongue, and corneal reflex

What is the motor function of CN V: Trigeminal?

Motor to the muscles of mastication

What CN is responsible for abducting the eye?

CN VI: ABDUCens

What CN is responsible for motor to the muscles of facial expression, stapedius and sensory of taste to the anterior 2/3 of the tongue?

CN VII: Facial

CN VII: Facial has parasympathetic function to the __________ _______.

Lacrimal glands

Which CN is responsible for the special sense of hearing and is involved in adjustment of posture, muscle tone, eye & head position?

CN VIII: Vestibulocochlear

Which CN is responsible for sensory to the posterior 1/3 of the tongue and pharynx?

CN IX: Glossopharyngeus

CN IX: Glossopharygeus provides motor to which muscle?

Stylopharyngeus, elevates during talking and swallowing. Also contributes to the gag reflex.

CN IX: Glossopharyngeus provides parasympathetic function to …

Assist with parotid gland function and secrete saliva to facilitate chewing, swallowing, etc.

Which CN is responsible for parasympathetic function to the heart, lungs, digestive tract down to the splenic fissure?

CN X: Vagus

CN X: Vagus provides the special sense of taste to the …

Pharynx and Epiglottis

CN X: Vagus provides brachial motor to what?

Pharyngeal muscles (swallowing) and laryngeal muscles (voice box)

Which CN provides motor function to the sternocleidomastoid and trapezius muscles?

CN XI: Spinal Accessory

Which CN provides motor function to the muscles of the tongue?

CN XII: Hypoglossal