Cranial Nerves IX, X, XI, XII

Question 1

Select the correct matching pair.
A) Spinal trigeminal nucleus: Discriminative touch
B)Trigeminal motor nucleus: Muscles of facial expression
C) Facial motor nucleus: Muscles of mastication
D) Main trigeminal sensory nucleus: Pain and temperature
E) Mesencephalic nucleus: Spindles from muscles of mastication

Answer 1

E) Mesencephalic nucleus: Spindles from muscles of mastication

Question 2

A patient reports a loss of pain sensation on the left side of the face after a stroke. What is the most likely location for this lesion?
A) Right main trigeminal sensory nucleus
B) Left main trigeminal sensory nucleus
C) Left facial sensory nucleus
D) Right spinal trigeminal tract/ nucleus
E) Left spinal trigeminal tract/ nucleus

Answer 2

E) Left spinal trigeminal tract/ nucleus

Question 3

Same patient with loss of pain sensation on the left side of the face. What brainstem level is likely involved?
A) Left lateral, dorsal medulla
B) Left anterior, medial pons 
C) Left anterior, medial medulla
D) Left lateral midbrain
E) Left anterior, medial midbrain

Answer 3

A) Left lateral, dorsal medulla

Question 4

Which is a function of cranial nerve VII?
A) Innervates stylopharyngeus muscle
B) Innervates muscles of mastication
C) Mediates taste on posterior 1/3 of tongue
D) Lacrimation
E) Provides visceral motor efferent fibers to the parotid gland

Answer 4

D) Lacrimation

Question 5

A patient complains of a droopy face, a dry red eye and noisy children who make her “ears hurt”. Select the true response.
A) The lesion must involve the facial sensory nucleus on the affected side because the eyes are red
B) The lesion must involve the superior salivatory nucleus, which can account for all these findings
C) It is most likely that the facial nerve is involved on the side ipsilateral to the facial weakness
D) It is most likely that the facial nerve is involved on the side contralateral to the facial weakness

Answer 5

C) It is most likely that the facial nerve is involved on the side ipsilateral to the facial weakness

Question 6

What is the axon type of CN XII?

Answer 6

Somatic motor

Question 7

What is the origin of CN XII?

Answer 7

hypoglossal nucleus

Question 8

What is the the peripheral termination of CN XII?

Answer 8

tongue muscles

Question 9

What are the results of a CN XII lesion?

Answer 9

(lower motor neuron) lesion:

a) Deviation toward lesion
b) Fasciculations
c) Atrophy

Question 10

Where does CN XII exit the brainstem?

Answer 10

adjacent to pyramid

Question 11

What is the origin of Hypoglossal Corticobulbar Fibers?

Answer 11

motor cortex

Question 12

Where do Hypoglossal Corticobulbar Fibers decussate?

Answer 12

adjacent to hypoglossal nucleus

Question 13

What is the result of a Hypoglossal Corticobulbar (upper motor neuron) lesion?

Answer 13

a) Deviation toward side opposite
b) No fasciculations
c) Minimal atrophy

Question 14

Select the correct statement
A) The tongue deviates to the side of XII nerve injury when protruded
B) The tongue deviates contralateral to the side of the lesion when upper motor neurons to the hypoglossal nucleus are injured
C) Tongue atrophy may be seen when XII nerve is injured
D) Cranial nerve XII is a somatic efferent nerve
E) All of the above are true

Answer 14

E) All of the above are true

Question 15

What is the axon type of CN XI?

Answer 15

Branchial motor

Question 16

What is the CNS origin of CN XI?

Answer 16

Accessory nucleus in cervical spinal cord (caudal medulla to ~C5)

Question 17

What is the peripheral termination of CN XI?

Answer 17

Sternocleidomastoid, trapezius

Question 18

What is the Effect of Accessory Nerve Lesion on the Trapezius Muscle?

Answer 18

a) Scapula and clavicle hang due to weak trapezius
b) Weak shoulder shrug as levator scapulae must work alone
c) Muscle atrophy leads to scalloped appearance of neck contour

*May be damaged in lymphadenectomy surgery for treatment of head and neck cancer including cancer of the oral cavity.

Question 19

What are the axon types for CN IX?

Answer 19

a) B, Branchial motor;
b) Ss, Somatic sensory;
c) Vm, Visceral motor;
d) Vs, Visceral sensory

Question 20

What is the CNS origin or termination ganglion for CN IX Somatic sensory axons?

Answer 20

Spinal trigeminal nucleus

Superior ganglion of IX

Question 21

What is the Peripheral origin or termination of CN IX somatic sensory axons?

Answer 21

Skin of outer ear

Question 22

What is the CNS origin or termination ganglion for CN IX visceral sensory axons?

Answer 22

Nucleus of solitary tract
Inferior ganglion of IX

• or from Nucleus of solitary tract, (spinal trigeminal nucleus)
  Inferior ganglion of IX

Question 23

What is the Peripheral origin or termination of CN IX visceral sensory axons?

Answer 23

Taste buds posterior 1/3 tongue, carotid body & sinus

*or Mucosa posterior 1/3 tongue, pharynx and middle ear

Question 24

What is the Peripheral origin or termination of CN IX visceral motor axons?

Answer 24

Parotid gland

Question 25

What is the CNS origin or termination ganglion for CN IX visceral motor axons?

Answer 25

Inferior salivatory nucleus | Otic ganglion

Question 26

What is the CNS origin or termination ganglion for CN IX branchial motor axons?

Answer 26

Nucleus ambiguus

Question 27

What is the Peripheral origin or termination of CN IX branchial motor axons?

Answer 27

Pharynx (stylopharyngeus)

Question 28

IX Afferents

Answer 28

``` Skin of ear & middle ear a) Superior ganglion of IX nerve b) Trigeminal spinal nucleus Posterior ⅓ of tongue a) Superior ganglion of glossopharyngeal nerve b) Trigeminal spinal nucleus ``` Carotid body: Blood O2, CO2 & pH Carotid sinus: Changes in blood pressure Inferior ganglion of glossopharyngeal nerve Solitary nucleus

Question 29

IX Efferents

Answer 29

- Nucleus ambiguus a) Stylopharyngeus muscle (elevates pharynx in speech & swallowing) b) Other pharyngeal and laryngeal muscles c) Inferior salivatory nucleus d) Otic ganglion - Parotid salivary gland

Question 30

Glossopharyngeal Neuralgia

Answer 30

- Similar to trigeminal neuralgia - Rare, but distressing - Sudden burst of pain starts in posterior tongue or wall of pharynx, then radiates to ear - Trigger zone on tongue/ pharynx and attacks precipitated by swallowing or talking - Pharmacologic management or tractotomy of spinal trigeminal tract in caudal medulla

Question 31

Select the true statement about IX. A) Serves pain and temperature for skin of outer ear and uses spinal trigeminal nucleus B) Information from carotid body and sinus reaches solitary nucleus via IX nerve C) Pain and temperature from nasal cavity and oropharynx use IX to reach spinal trigeminal nucleus D) Nucleus ambiguus is a motor nucleus for parts of XI and X E) All the above are true

Answer 31

E) All the above are true

Question 32

What are the axon types of CN X?

Answer 32

B, Branchial motor; Ss, Somatic sensory; Vm, Visceral motor; Vs, Visceral sensory

Question 33

X Afferents

Answer 33

Skin of ear a) Superior ganglion of X b) Trigeminal spinal nucleus c) Epiglottis – taste d) Epiglottis – visceral sensation e) Thoracic and abdominal viscera f) Aortic arch baroreceptors blood pressure & chemoreceptors (blood O2 & CO2) Inferior ganglion of vagus nerve Solitary nucleus of vagus nerve

Question 34

Select the correct match. A) Nucleus ambiguus: IX & X; motor pharynx and larynx B) Dorsal motor nucleus: Thoracic, abdominal and pelvic viscera C) Spinal trigeminal nucleus: V, IX, X, XI D) Nucleus of the solitary tract: VI, VII, IX, X E) All of the above are correct

Answer 34

A) Nucleus ambiguus: IX & X; motor pharynx and larynx

Question 35

X Efferents

Answer 35

1) Nucleus ambiguus (lateral) - Muscles of speech and swallowing 2) Nucleus ambiguus (medial) - Heart and lungs 3) Dorsal motor nucleus of the vagus - All viscera up to transverse colon (parasympathetic)

Question 36

Gag reflex

Answer 36

Touch one side of pharynx; elicit a bilateral response CN IX – afferent component CN X – efferent component Central connections not clear *Central connections may involve the spinal trigeminal tract & nucleus or the solitary tract & nucleus or both as well as the nucleus ambiguus

Question 37

Tongue Thrust Reflex

Answer 37

- Infants, may persist up to eight years - Can contribute to speech and orthodontic issues - CN V or XI: afferent limb - CN XII: efferent limb *Tongue thrust in response to stimulation of pharynx wall; up to 4 – 6 months of age 67–95% of children 5–8 years old exhibit tongue thrust

Question 38

Other Clinical Considerations of X

Answer 38

- Vasovagal syncopy: response to a trigger, vagus decreases heart rate & blood pressure, decreasing cerebral blood flow, results in fainting and confusion - Vagal nerve stimulator: Stimulate vagal nerve to modulate mood or seizure activity - Unknown how this works Afferent fibers to nucleus of solitary tract project to other CNS locations *Syncopy – “sudden, transient loss of consciousness and postural tone” * Proposed mechanisms vagal stimulation works include: a) Alteration of norepinephrine released by projections of solitary tract to the locus ceruleus b) Elevated levels of GABA inhibitory neurotransmitter c) Inhibition of aberrant cortical activity by recticular activating system

Question 39

Jugular Foramen Syndrome

Answer 39

- IV, X, XI, XII nerves & sympathetic nerve (internal carotid nerve) and are at risk of entrapment by a skull base tumor - Nasopharyngeal primary or metastatic (to upper cervical lymph node) malignancy - Symptoms vary by number/ type of nerve involved: Pain in ear (IX, X) Headache, meningeal irritation (X) Hoarseness (X) Dysphagia (X) Horner syndrome (Internal carotid nerve): Ptosis, pupillary constriction Loss of gag reflex (IX, X) *When an adult complains of constant pain in the ear and the middle ear is unremarkable a pharyngeal malignancy a distinct possibility!!!!! 1) Wasting of tongue, deviates to side of lesion on protrusion 2) Oropharyngeal sensory loss 3) Arch of soft palate droops 4) Inability to adduct vocal cord to midline 5) Uvula deflects to side that is contralateral to lesion; unopposed levator palatini 6) Weakness and atrophy of sternocleidomastoid and trapezius due to XI involvement