Cranial Nerves IX, X, XI, XII Flashcards
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
E) Mesencephalic nucleus: Spindles from muscles of mastication
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
E) Left spinal trigeminal tract/ nucleus
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
A) Left lateral, dorsal medulla
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
D) Lacrimation
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
C) It is most likely that the facial nerve is involved on the side ipsilateral to the facial weakness
What is the axon type of CN XII?
Somatic motor
What is the origin of CN XII?
hypoglossal nucleus
What is the the peripheral termination of CN XII?
tongue muscles
What are the results of a CN XII lesion?
(lower motor neuron) lesion:
a) Deviation toward lesion
b) Fasciculations
c) Atrophy
Where does CN XII exit the brainstem?
adjacent to pyramid
What is the origin of Hypoglossal Corticobulbar Fibers?
motor cortex
Where do Hypoglossal Corticobulbar Fibers decussate?
adjacent to hypoglossal nucleus
What is the result of a Hypoglossal Corticobulbar (upper motor neuron) lesion?
a) Deviation toward side opposite
b) No fasciculations
c) Minimal atrophy
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
E) All of the above are true
What is the axon type of CN XI?
Branchial motor
What is the CNS origin of CN XI?
Accessory nucleus in cervical spinal cord (caudal medulla to ~C5)
What is the peripheral termination of CN XI?
Sternocleidomastoid, trapezius
What is the Effect of Accessory Nerve Lesion on the Trapezius Muscle?
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.
What are the axon types for CN IX?
a) B, Branchial motor;
b) Ss, Somatic sensory;
c) Vm, Visceral motor;
d) Vs, Visceral sensory
What is the CNS origin or termination ganglion for CN IX Somatic sensory axons?
Spinal trigeminal nucleus
Superior ganglion of IX
What is the Peripheral origin or termination of CN IX somatic sensory axons?
Skin of outer ear
What is the CNS origin or termination ganglion for CN IX visceral sensory axons?
Nucleus of solitary tract
Inferior ganglion of IX
- or from Nucleus of solitary tract, (spinal trigeminal nucleus)
Inferior ganglion of IX
What is the Peripheral origin or termination of CN IX visceral sensory axons?
Taste buds posterior 1/3 tongue, carotid body & sinus
*or Mucosa posterior 1/3 tongue, pharynx and middle ear
What is the Peripheral origin or termination of CN IX visceral motor axons?
Parotid gland
What is the CNS origin or termination ganglion for CN IX visceral motor axons?
Inferior salivatory nucleus
Otic ganglion
What is the CNS origin or termination ganglion for CN IX branchial motor axons?
Nucleus ambiguus
What is the Peripheral origin or termination of CN IX branchial motor axons?
Pharynx (stylopharyngeus)
IX Afferents
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
IX Efferents
- 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
Glossopharyngeal Neuralgia
- 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
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
E) All the above are true
What are the axon types of CN X?
B, Branchial motor;
Ss, Somatic sensory;
Vm, Visceral motor;
Vs, Visceral sensory
X Afferents
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
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
A) Nucleus ambiguus: IX & X; motor pharynx and larynx
X Efferents
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)
Gag reflex
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
Tongue Thrust Reflex
- 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
Other Clinical Considerations of X
- 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 norepinephrinereleased by projections of solitary tract to the locus ceruleus
b) Elevated levels of GABA inhibitory neurotransmitter
c) Inhibition of aberrant cortical activity byrecticular activating system
Jugular Foramen Syndrome
- 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
