CN V and VII Flashcards
What are the divisions of CN V, trigeminal?
V1 - opthalamic
V2 - maxillary
V3 - mandibular
Through which bone cavity does V1 of CN V, trigeminal, exit the cranial cavity?
superior orbital fissure
Through which bone cavity does V2 of CN V, trigeminal, exit the cranial cavity?
foramen rotundum
Through which bone cavity does V3 of CN V, trigeminal, exit the cranial cavity?
foramen ovale
What are the main functions of CN V, trigeminal?
- sensory: transmission of tactile, proprioception, pain/temp info from the head (e.g. DC and STT of head)
- motor: controls muscles of mastication
What is the V1 nerve and what is it responsible for? Is it motor or sensory?
- opthalamic nerve
- pure sensory
- eye and forehead
What is the V2 nerve and what is it responsible for? Is it motor or sensory?
- maxillary nerve
- pure sensory
- cheek and upper teeth
What is the V3 nerve and what is it responsible for? Is it motor or sensory?
- mandibular nerve
- sensory: mandible and lower teeth
- motor: muscles of mastication
Which division of CN V, trigeminal, has a motor component?
V3, mandibular nerve
How many ganglia are in the trigeminal ganglion?
3
Which branch of V1 innervates the skin to the forehead and scalp?
supraorbital nerve
What does V1 innervate?
- skin to forehead and scalp
- upper eyelid, tip of the nose
- cornea and nasal cavity
- paranasal air sinuses
What does V2 innervate?
- maxillary air sinus
- nasal cavity
- lower eyelid, skin of cheek, upper lip
- maxillary (upper) teeth and gum
Which branch of V2 innervates the nasal cavity and maxillary air sinus?
infraorbital branch
TRUE or FALSE: V1 is a mixed nerve.
FALSE –> V3 is a mixed nerve (sensory and motor)
Which branch of the trigeminal nerve (CN V) is the largest?
V3
What does the sensory component of V3 innervate?
- lower lip, skin of mandible, chin
- mandibular teeth and gums
- anterior 2/3 tongue
Which branch of V3 innervates sensation to the mandibular teeth and gums?
inferior alveolar nerve
Which branch of V3 innervates sensation to the anterior 2/3 tongue?
lingual nerve
Is the sensory trigeminothalamic tract contralateral or ipsilateral?
contralateral
What are the 3 sensory trigeminal subnuclei? Where are they found?
- spinal nucleus, 2. chief/main nucleus, 3. mesencephalic nucleus
- found in the brainstem
Where are the synapses in the pain and temperature pathway for the trigeminothalamic tract?
- spinal nucleus
- ventral posteriomedial nucleus (VPM) of the thalamus
In comparison with the spinothalamic tract, where does pain/temperature info enter the CNS in the trigeminothalamic tract?
spinothalamic tract: substantia gelatinosa in the dorsal horn of the SPINAL CORD
trigeminothalamic tract: MEDULLA
Where are the synapses in the light touch and pressure pathway for the trigeminothalamic tract?
- chief/main nucleus
- VPM nucleus in thalamus
In comparison with the dorsal columns medial lemniscal tract, where does light touch and pressure info enter the CNS in the trigeminothalamic tract?
dorsal columns medial lemniscal tract: cuneate and gracile fasciculi in SPINAL CORD
trigeminothalamic tract: PONS
Where are the synapses in the proprioception pathway for the trigeminothalamic tract?
- mesencephalic nucleus
- VPM in the thalamus
Proprioceptive info from which muscles are sent to the brainstem in the V3 tract?
muscles of mastication
Which nucleus in the brainstem acts on motor action of the trigeminal nerve? which division of the trigeminal tract synapses here?
- motor nucleus of V
- V3
What nerve extends from the motor nucleus of V to the muscles of mastication?
mandibular nerve
TRUE or FALSE: the motor fibres of the trigeminal nerve go through the trigeminal nucleus.
FALSE
What are the muscles of mastication?
- masseter muscle
- temporalis muscle
All upper motor neurons, except _________________, form the corticobulbar tracts (of CN V). They act on ___________ lower motor neurons.
- lower facial nucleus
- bilateral
The lower facial nucleus acts on _____________ lower motor neurons.
contralateral
Through which bone cavity does CN VII, facial, exit the cranial cavity?
internal acoustic meatus
TRUE or FALSE: CN VII, facial nerve, is only sensory and motor.
FALSE –> mixed nerve: sensory, motor, PARASYMPATHETIC
What does the motor component of CN VII, facial, innervate?
- muscles of facial expression
- stapedius muscle
What does the sensory component of CN VII, facial, innervate?
taste to anterior 2/3 tongue (via chorda tympani)
What does the parasympathetic component of CN VII, facial, innervate?
-lacrimal gland
- sublingual and submandibular salivary glands
What are the branches to the muscles of facial expression?
- temporal
- zygomatic
- buccal
- marginal mandibular
- cervical
Through which bone cavity does CN VII, facial, exit the cranial cavity?
Internal Acoustic Meatus
Which cranial nerves are involved in the corneal reflex? Describe the corneal reflex.
- CN V, trigeminal: afferent arc (sensory)
- CN VII, facial: efferent arc (motor) via innervation of orbicularis oculi
- reflex: consensual blinking of both eyes in response to stimulation of one eye
Which muscle does CN VII, facial, innervate in the corneal reflex?
orbicularis oculi
Which cranial nerve innervates the stapedius muscle?
CN VII, facial
List the facial nerve nuclei and their functions.
- facial motor nucleus –> motor
- superior salivary nucleus –> PNS
- nucleus of solitary tract (NTS) –> taste
Is the motor component of CN VII, facial, to the upper face contralateral, ipsilateral, or both?
upper face = contralateral and ipsilateral
Is the motor component of CN VII, facial, to the lower face contralateral, ipsilateral, or both?
lower face = contralateral
What condition might arise if there is damage to the facial nerve? What are the symptoms?
facial nerve palsy - weakness or paralysis on one side of the face
What is the name of the facial nerve palsy that is idiopathic in origin?
Bell’s palsy
what part of the face would be paralyzed if there is a right upper motor neuron lesion in the facial nerve?
contralateral (left) lower 2/3 face
What part of the face would be paralyzed if there is a left lower motor neuron lesion in the facial nerve?
ipsilateral (left) half of face
Which branch of the facial nerve is responsible for taste?
chorda tympani
Describe the taste pathway of the facial nerve.
facial nerve –> geniculate ganglion –> chorda tympani
Which nucleus in the brainstem does the synapse occur for the facial nerve component of taste?
nucleus solitary tract (NTS)
salivation is innervated by which 2 cranial nerves? Which one is preganglionic? postganglionic?
CN VII, facial = preganglionic
CN V, trigeminal = postganglionic
Which division of CN V is the lacrimal nerve?
V1
What are the 4 cranial nerves with parasympathetic innervation?
- CN III, oculomotor
- CN V, facial
- CN IX, glossopharyngeal
- CN X, vagus