Unit 4_Cranial Nerves

Question 1

How many paired cranial nerves arise directly from the brain and brainstem?

Answer 1

12 paired cranial nerves

Question 2

Cranial nerves carry what primarily for the head/neck?

Answer 2

Carrying sensory, motor and autonomic information

Question 3

What kind of nerves are cranial nerves, meaning damage to cranial nerve nuclei cause IPSILATERAL impairment?

Answer 3

peripheral nerves

Question 4

Where does the Olfactory nerve originate?

Answer 4

on olfactory mucosa within the upper nasal cavity

Question 5

Where do axons from the sensory nerves travel to synapse on the olfactory bulbs?

Answer 5

via olfactory nerves through the cribriform plate (Ethmoid bone)

Question 6

Where does information from the olfactory bulbs travel, which run in the olfactory sulcus to the olfactory processing area in the temporal lobe?

Answer 6

via the olfactory tracts

Question 7

What is the pathway of Cranial Nerve I – Olfactory Nerve?

Answer 7

Olfactory nerve –> Cribriform plate –> Olfactory bulbs –> Olfactory tracts –> Temporal lobe (Entorhinal Cortex)

Question 8

What is a Cranial Nerve I – Olfactory Nerve Function and Lesion that occurs when there’s a loss of sense of smell? Impairment can be unilateral or bilateral depending on cause.

Answer 8

Anosmia

Question 9

What is a Cranial Nerve I – Olfactory Nerve Clinical Disorders and Syndromes that occurs and is rarely noticeable clinically as the contralateral nostril compensates for loss?

Answer 9

Unilateral anosmia (ipsilateral)

Question 10

What is a Cranial Nerve I – Olfactory Nerve Clinical Disorders and Syndromes that occurs and the first complaint is often the LOSS OF TASTE due to contribution of smell to detection of flavor?

Answer 10

Bilateral anosmia (bilateral involvement)

Question 11

What are the following common causes for:
- Head trauma with injury to the ethmoid bone
- Conditions such as Parkinson’s, Alzheimer’s, and COVID

Answer 11

Cranial Nerve I – Olfactory Nerve Clinical Disorders and Syndromes

Question 12

What cranial nerve is associated with visual information received in the retina, travels via the optic nerve to the primary visual cortex located in the occipital lobe?

Answer 12

Cranial Nerve II – Optic Nerve Location and Pathway

Question 13

What is the pathway of Cranial Nerve II – Optic Nerve?

Answer 13

Optic nerve –> optic chiasm –> optic tract –> Lateral geniculate Nucleus of thalamus –> primary visual cortex (Occipital Lobe)

Question 14

Where do we see partial crossing of the fibers (from nasal retina-peripheral vision) so that fibers from one hemiretina crosses to the contralateral optic tract?

Answer 14

at the optic chiasm

Question 15

What sensory nerve is Cranial Nerve II – Optic Nerve associated with?

Answer 15

Vision

Question 16

What is an inflammatory demyelinating condition of the optic nerve (CN II)? The primary sign of Multiple Sclerosis – blurred vision.

Answer 16

Optic neuritis

Question 17

What cranial nerve is located in the upper midbrain?

Answer 17

Cranial Nerve III – Oculomotor Nerve

Question 18

What kind of muscles originate in a tendinous ring at the orbital apex and insert on the sclera of the eye?
4 rectus muscles
2 oblique muscles

Answer 18

Extraocular muscles (CN III)

Question 19

What muscle is responsible for lifting the eyelid as part of Cranial Nerve III – Oculomotor Nerve?

Answer 19

Levator Palpebrae

Question 20

The Cranial Nerve III – Oculomotor Nerve handles muscle function to extraocular muscles, all eye movement with exception of what?

Answer 20

Abduction of the eye performed by lateral rectus (CN6)

Rotational movement of the eye performed by superior oblique (CN4)

Question 21

What do parasympathetic fibers innervate the ciliary muscles of the lens of the eye for?

Answer 21

pupil constriction

Question 22

What are the following symptoms of?
Ipsilateral eye will deviate laterally and inferiorly
Ptosis (droopy eyelid)
Dilated pupil (enlarged)

Answer 22

Symptoms of cranial nerve III -oculomotor nerve palsy

Question 23

What is loss of innervation to Levator palpebrae muscle?

Answer 23

Ptosis (droopy eyelid)

Question 24

What is loss of function to ciliary muscles that constrict the pupil?

Answer 24

Dilated pupil (enlarged)

Question 25

What is the most common patient presentation of Cranial Nerve III – Oculomotor Nerve Clinical Disorders and Syndromes?

Answer 25

double vision (diplopia) Common patient complaint – Dizziness!

Question 26

What cranial nerve is located in the midbrain, has nerve fibers decussate (cross) in the midbrain just prior to exiting the brainstem, and is the smallest cranial nerve, but longest path?

Answer 26

Cranial Nerve IV – Trochlear Nerve

Question 27

What cranial nerve motor function is to the Superior Oblique muscle (pulls the eye inferiorly and medially)?

Answer 27

Cranial Nerve IV – Trochlear Nerve

Question 28

Damage to the nucleus of Cranial Nerve IV – Trochlear Nerve will cause what?

Answer 28

CONTRALATERAL Superior Oblique palsy Contralateral eye may deviate ”up and out” as there are no opposing forces on the Inferior Oblique muscle

Question 29

Damage to the Cranial Nerve IV – Trochlear Nerve AFTER it has left the brainstem will cause what?

Answer 29

IPSILATERAL palsy

Question 30

What clinical disorder are the following signs/symptoms of? May see head tilted AWAY from the side of the paralysis with chin tucked - Helps to align visual fields Most common patient presentation = double vision (diplopia) - When looking down and in Also – Dizziness!

Answer 30

Cranial Nerve IV – Trochlear Nerve

Question 31

What cranial nerve is located in the pons, exits the brainstem ventrally at the pontomedullary junction?

Answer 31

Cranial Nerve VI – Abducens Nerve

Question 32

What cranial nerve is the Motor Nerve to the Lateral Rectus Muscle and controls abduction of the eye?

Answer 32

Cranial Nerve VI – Abducens Nerve

Question 33

Damage to the nucleus of Cranial Nerve VI – Abducens Nerve will cause what?

Answer 33

ipsilateral Lateral Rectus palsy Ipsilateral eye will deviate medially - no opposing forces on the Lateral rectus muscle

Question 34

What is the most common patient complaint of Cranial Nerve VI – Abducens Nerve Clinical Disorders and Syndromes?

Answer 34

double vision (diplopia) Also – Dizziness!

Question 35

What are the 3 major branches of Cranial Nerve V – Trigeminal Nerve?

Answer 35

ophthalmic (V1) maxillary (V2) mandibular (V3)

Question 36

What cranial nerve is located in the pons?

Answer 36

Cranial Nerve V – Trigeminal Nerve

Question 37

What cranial nerve provides sensory to the face and anterior 2/3 of the tongue, and touch, pain, temp, joint position and vibration?

Answer 37

Cranial Nerve V – Trigeminal Nerve

Question 38

What cranial nerve provides motor to the muscles of mastication, including the masseter, temporalis, medial and lateral pterygoid muscles and the motor root from mandibular division?

Answer 38

Cranial Nerve V – Trigeminal Nerve

Question 39

What cranial nerve provides sensory input for corneal reflex?

Answer 39

Cranial Nerve V – Trigeminal Nerve

Question 40

Impaired sensation to ipsilateral side of the face presents as what?

Answer 40

Cranial Nerve V – Trigeminal Nerve Lesion Presentation

Question 41

Loss of motor to ipsilateral muscles of mastication, including difficulty chewing, swallowing presents as what?

Answer 41

Cranial Nerve V – Trigeminal Nerve Lesion Presentation

Question 42

Impaired corneal reflex presents as what?

Answer 42

Cranial Nerve V – Trigeminal Nerve Lesion Presentation

Question 43

What Cranial Nerve V – Trigeminal Nerve Clinical Disorders and Syndromes is the following: Categorized by brief episodes of severe pain Most common in V2 and V3 distributions Cause generally unknown, can be present in MS with demyelination of trigeminal nerve

Answer 43

Trigeminal neuralgia

Question 44

What cranial nerve is the following: Sits in the pons Exits the brainstem at the pontomedullary junction Branches into 5 motor segments: Temporal Zygomatic Buccal Mandibular Cervical

Answer 44

Cranial Nerve VII – Facial Nerve

Question 45

What cranial nerve includes the following: Special sense of taste to the anterior 2/3 of the tongue Motor to the muscles of facial expression Motor to stapedius Along with tensor tympani [CN5], works to dampen movements of the inner ear ossicles for modulation of acoustic signal intensity Parasympathetic to the lacrimal glands Both SENSORY AND MOTOR

Answer 45

Cranial Nerve VII – Facial Nerve

Question 46

What cranial nerve is the following motor function associated with: Temporal branch - Frontalis - **Orbicularis Oculi - Corrugator supercilii Zygomatic branch Buccal branch Marginal Mandibular branch Cervical branch

Answer 46

Cranial Nerve VII – Facial Nerve

Question 47

Loss of motor to the contralateral lower face involves what neuron? - Unilateral cortical lesion (or corticobulbar lesion) usually spare the forehead because of bilateral innervation from bilateral motor cortices

Answer 47

UMN

Question 48

Ipsilateral loss of motor to the whole face (Bell’s Palsy) involves what neuron? - Loss of corneal blink reflex due to damaged motor output - CN 5, 7

Answer 48

LMN

Question 49

What Cranial Nerve VII – Facial Nerve Clinical Disorders and Syndromes usually has a viral cause, impairment to all divisions of the facial nerve? Gradually recover, usually prescribed steroid Symptoms: Unilateral facial weakness Inability to close eyelid Dry eye due to lacrimal gland impairment

Answer 49

Bell's Palsy

Question 50

What cranial nerve involves the vestibular nerve, which exits the brainstem at the pontomedullary junction, lateral to the facial nerve? 2 Divisions: Vestibular Cochlear

Answer 50

Cranial Nerve VIII – Vestibulocochlear Nerve

Question 51

What cranial nerve is a sensory nerve and involves the special sense of hearing? Vestibular nuclei plays an important role in adjustment of posture, muscle tone, eye and head position.

Answer 51

Cranial Nerve VIII – Vestibulocochlear Nerve

Question 52

What cranial nerve involves unilateral hearing loss? Sx: dizziness and imbalance – need further testing to determine peripheral vs central dizziness and etiology within vestibular system - Abnormal Nystagmus Differentiate between Sensorineural and Conductive hearing loss with Rinne’s Test

Answer 52

Cranial Nerve VIII – Vestibulocochlear Nerve

Question 53

What cranial nerve originates in the medulla oblongata of the brainstem? Exits the brainstem at the ventrolateral Medulla.

Answer 53

Cranial Nerve IX – Glossopharyngeal Nerve

Question 54

What cranial nerve involves the following: Sensory: to the posterior 1/3 tongue and pharynx, general sensation to the carotid body Motor: supplies stylopharyngeus muscle Elevates the pharynx during talking and swallowing Contributes to the gag reflex with CN 10 (vagus) Parasympathetic: assist with parotid gland function (secrete saliva to facilitate chewing, swallowing, etc.

Answer 54

Cranial Nerve IX – Glossopharyngeal Nerve

Question 55

What cranial nerve presents as the following when there's a lesion present? Impaired sensation to the posterior 1/3 tongue, pharynx, and palate (impaired taste) Difficulty swallowing (ipsilateral stylopharyngeus) Impaired gag reflex

Answer 55

Cranial Nerve IX – Glossopharyngeal Nerve

Question 56

What cranial nerve involves the following: More likely to be a central lesion than peripheral lesion. However, peripheral lesions can be caused by demyelinating diseases, diabetic neuropathy, surgical damage with head/neck surgeries. Ask the patient to say ’Ahh’ – look for uvula elevation and symmetrical palate movements

Answer 56

Cranial Nerve IX – Glossopharyngeal Nerve

Question 57

What cranial nerve is the “Wandering nerve” and exits the brainstem at the Medulla?

Answer 57

Cranial Nerve X – Vagus Nerve

Question 58

What cranial nerve involves the following: Parasympathetic: function to heart, lungs, digestive tract down to the splenic fissure REST and DIGEST Brachial motor: pharyngeal muscles (swallowing) and laryngeal muscles (voice box) Sensory: special sense of taste from pharynx and epiglottis, chemo and baroreceptors of the aortic arch

Answer 58

Cranial Nerve X – Vagus Nerve

Question 59

What cranial nerve involves the following clinical disorders and syndromes: Postural Orthostatic Tachycardia Syndrome (POTS) - Abnormal blood pressure and heartrate response to activity, positioning, and even rest Vasovagal Syncope Digestive disorders (gut-brain axis)

Answer 59

Cranial Nerve X – Vagus Nerve

Question 60

What cranial nerve arises from the upper 6 segments of the cervical spinal cord?

Answer 60

Cranial Nerve XI – Spinal Accessory Nerve

Question 61

What cranial nerve involves the following nerve function: MOTOR NERVE to sternocleidomastoid and trapezius muscle - Sternocleidomastoid (SCM): tilt head to ipsilateral side; rotate to contralateral side - Trapezius: elevates shoulders

Answer 61

Cranial Nerve XI – Spinal Accessory Nerve

Question 62

What cranial nerve involves the following when a lesion is present: Ipsilateral weakness with shoulder shrug Weakness of head turn AWAY from lesion

Answer 62

Cranial Nerve XI – Spinal Accessory Nerve

Question 63

What cranial nerve involves impairment commonly caused by: - Trauma (particularly to cervical spine) - Surgical procedures - Lymph node removal/biopsy

Answer 63

Cranial Nerve XI – Spinal Accessory Nerve

Question 64

What cranial nerve exits the brainstem at the ventral medulla between the pyramid and inferior olivary nucleus? Exits through hypoglossal foramen.

Answer 64

Cranial Nerve XII – Hypoglossal Nerve

Question 65

What cranial nerve involves MOTOR NERVE to muscles of the tongue?

Answer 65

Cranial Nerve XII – Hypoglossal Nerve

Question 66

What causes CONTRALATERAL tongue weakness involving the Corticobulbar tract and Primary motor cortex?

Answer 66

Cranial Nerve XII – Hypoglossal NerveLesion Presentation

Question 67

What cause IPSILATERAL tongue weakness?

Answer 67

Cranial Nerve XII – Hypoglossal NerveLesion Presentation

Question 68

What cause tongue muscles are protrusion muscles, so will see tongue deviate TOWARD the weakness?

Answer 68

Cranial Nerve XII – Hypoglossal NerveLesion Presentation