Week 9 Cranial Nerves Flashcards
Neural Tube Structure - Plates
- Basal plate is (anterior/posterior) and (closer/further) to the neuron - most likely to be (motor/sensory) neurons
- Alar plate is (closer/further away) - more likely to be (motor/sensory) neurons
- Sulcus _____ separates anterior and posterior sections
- Cranial nerve organization is similar in respect to spinal cord/neural development organization
- However, brainstem has both visceral and somatic sensory and motor fibers
anterior; closer; motor; further away; sensory; limitans;
Neural Tube Structure - Plates
- Sensory fibers migrate from being (superior/inferior) to being more (medial/lateral)
- Motor fibers migrate from being (superior/inferior) to being more (medial/lateral)
- Knuckles represent the sulcus limitans that separates the 2
superior; lateral; inferior; medial;
Cranial Nerve Nuclei
- Alar plate - (medial/lateral) to sulcus limitans
- Basal plate - (medial/lateral) to sulcus limitans
- Sensory
- Special visceral afferent: smell and taste
- Special somatic afferent: hearing and balance
- General somatic afferent:
- General visceral afferent: vessels, heart, lungs, digestive
- Motor
- Visceral motor/general visceral efferent: tears/salivation
- Special visceral efferent: swallow
- General somatic efferent: facial expression
- GVA, GSA, GVE, GSE, SVE
lateral; medial;
Cranial Nerve Nuclei
- Nuclei run the length of the (cell/brainstem) – midbrain, pons and medulla
- The area involved in a lesion/infarction/ischemia – can affect CN nuclei
- Sulcus limitans divides sensory and motor nerves
- Sensory is (medial/lateral)
- Motor is (medial/lateral)
- Midline separates L and R sides
brainstem; lateral; medial;
- PICA might impact (medial/lateral) - affecting sensory nerves (more/less)
- Vertebral artery and PIC at caudal level may impact (anterior/posterior) aspect more
lateral; more; anterior
Corticonuclear System = (Motor/Sensory)
- Cells of origin
- Lateral aspect of (M1/S1) (upper motor neuron) → corona radiata → internal capsule
- Crus cerebri of midbrain to nuclei within midbrain, pons, or medulla
- Crossover: at the level of the nucleus / where it exits
- Exits at (same/different) levels of pons/medulla depending on where the nucleus is
- Nucleus: (dorsal/ventral) horn lower motor neuron homologue
Motor; M1; different; ventral
Corticonuclear(bulbar) System: Somatic Efferent
- Function
- (Involuntary/Voluntary) motor control of striated muscles innervated by CN
- Trigeminal N CN 5
- Facial N CV 7
- Glossopharyngeal N CN 9
- Vagus N CN 10
- Accessory N CN 11
- Hypoglossal N CN 12
- General somatic efferent and special somatic efferent
Voluntary
Corticonuclear Pathway and Perfusion
- Internal capsule perfusion important - (anterior/posterior) choroidal , ______ artery
- Crus cerebri – (anterior/posterior) cerebral artery
anterior; lenticulostriate; posterior
Internal capsule genu has (facial/feet) information
facial
Pathway of CN nuclei
- (Right/Left) cortex (UMN/LMN)
- Corona radiata
- Crus cerebri
- Internal capsule (genu) bc face
- Nucleus in (hindbrain/midbrain) where crossover occurs
- Right side (UMN/LMN) of the eye
Left; UMN; midbrain; LMN
Trochlear Nerve CN IV
- Nucleus sits in (midbrain/hindbrain)
- Exit location is in (midbrain/hindbrain)
midbrain; midbrain
Trochlear Nerve (CN IV)
- UMN is CL to the nucleus of the nerve
- Trochlear N innervates superior oblique muscle - responsible for looking (down and out/up and in)
- Intorsion - shifting of the eye towards the nose
- Different muscles pull on the eye - all of the muscles need to work properly to keep eye in proper alignment (think of quad pull on patella) - if one doesn’t work you have shifting of the eyeball
down and out;
Trochlear Nerve (CN IV) Clinical Correlation
Clinical Correlations - Trochlear Nerve
- CN IV
- Lesion
- (Down and out/Up and in) eye position
- Ipsilateral
- Inability to move eye (downward and outward/up and in)
- Ipsilateral
- Testing
- Ability to move eyes
Up and in; downward and outward;
CN 6 Abducens N
- Nucleus within (pons/heart)
- Exits within (pons/heart)
pons; pons
CN 6 Abducens Nerve
- Innervates lateral rectus muscle of the eye - responsible for (lateral/superior) gaze
- ABDucens N - responsible for (abduction/adduction) of the eyeball
lateral; abduction
Clincial Correleations - CN VI - Abducens Nerve
- CN VI lesion
- Impaired lateral rectus muscle
- (Contralateral/Ipsilateral) to side of lesion
- Affected eye is (abducted/adducted) – bc (adducting/abducting) the eye are lost
- Intact medial rectus
- Patient presents with diplopia when attempting to gaze to side of lesion
- Testing
- Assess for (superior/lateral) gaze: do they have double vision
Ipsilateral; adducted; abducted; lateral
Clinical Correlations CN 6 Abducens Nerve
Turn head away from the object, gaze is opposite the lesion. eyeball can (adduct/abduct), no double vision
abduct
Vestibular Cochlear: Special Somatic Afferent
Vestibulocochlear - special somatic afferent
- Cochlear nerve and nuclei: (hearing/talent)
- Vestibular nerve and nuclei: (balance/athleticism)
hearing; balance
Spinal Accessory Nerve - CN 11
- Everyone’s spinal accessory nerve CN XI has a (cervical/thoracic) component from C_-C_ (accessory nucleus)
- CN XI innervates (trapezius and SCM/rhomboids and levator scap)
- GSE fibers
- Nucleus of accessory nerve or “accessory nucleus” in upper cervical spinal cord segments
- “Cranial nerve” because it exits via the (cranium/IVF) and not out of the cervical lateral recess/opening
- Upper motor neuron axons travel by the (corticobulbar/corticospinal) tract
- Nuclei sit within the (ventral/dorasal) horn C_-C_
cervical; C1-C5; trapezius and SCM; cranium; corticobulbar; ventral; C1-C5
Clinical Correlation - CN XI
- (Abduction/Adduction) is compromised
- (Upper/Lower) trapezius and (serratus anterior/rhomboids) force couple
- Clinical test
- MMT assessing for muscle weakness
- UT - shrug
- MT- T’s
- LT - Y’s
- SCM: may be intact
- Scapular flip sign
- ER is not weak. Scapula breaks.
- If MT is not working properly, the scapular vertebral border will come off of the thoracic wall
Abduction; Upper; serratus anterior
Spinal Accessory Nerve Palsy: Associated Signs & Symptoms
Trap: thumbs (UP/Down) - traps live (ABOVE/BELOW) rhomboids
Rhomboids: thumbs (UP/DOWN). Rhomboids live (ABOVE/BELOW) trapezius
UP; ABOVE; DOWN; BELOW
Hypoglossal Nerve CN XII
- Hypoglossal nerve XII
- Intrinsic and extrinsic (feet/tongue) muscles
- (GSE/GSA) fibers
- Nucleus in brainstem
tongue; GSE;
Clinical Correlation - CN XII
- Clinical test - stick out tongue
- UMN – tongue deviates (towards/away) from the lesion
- LMN - tongue deviates (towards/away) the side of the lesion
Pic - LMN
away; towards
(Simple/Mixed) Cranial Nerves
- III - oculomotor
- V- trigeminal
- VII- facial
- IX- glossopharyngeal
- X- vagus
- These nerves have a sensory and motor or a parasympathetic branch
Mixed
CN III - Oculomotor Nerve
- (GSE/GSA) fibers
- Extraocular muscles
- *innervates muscles abducens and trochlear nerves (do/don’t)
GSE; don’t
CN III - Oculomotor Nerve
- (GVE/GVA) fibers
- Preganglionic parasympathetic fibers
Accommodation: changing shape of lens (focus)
Pupillary light reflex : pupillary contraction to light
GVE;
CN III oculomotor nerve
Lower motor neuron injury of the nuclei
- (Droopy/Raised) eyelid (Ptosis)
- Ipsilateral eye will look (down and out/up and in) (CN III is out, CNIV is intact. CNIV and VI will pull eyes down and out.
- Impaired eye movements
- Ipsilateral
- Loss of pupillary light reflex
- Testing
- Ability to move eyes
- Pupillary light reflex
- Understand
- UMN, ie CVA will impact (same/opposite) side : Right sided brain lesion → (right/left) side ptosis
Droopy; down and out; opposite; left
CN 5 - Trigeminal Nerve
- Nucleus in midbrain, pons, medulla and into spinal cord
- Nerve exits at the (feet/pons)
pons
CN V Trigeminal Nerve
- V1 - (ophthalmic/maxillary)
- V2 - (ophthalmic/maxillary)
- V3 - (mandibular/ophthalmic)
- Sensory does not equal taste
- Sensory only - (V1 and V2/V3)
- Mixed - (v1 & v2/V3)
- Face, eye most of oral and nasal mucosa, teeth and tongue (anterior ⅔)
- Discriminative touch
- Principal /chief trigeminal nucleus (pons)
- (GSE/GSA)
- Nociception, temperature and crude touch
- Spinal trigeminal nucleus
- (GSE/GSA)
- Nasal mucosa and nociception: chemesthesis
- Cervical spine contribution to trigeminal nerve may play a role in cervicogenic (flu/headaches )
ophthalmic; maxillary; mandibular; V1 and V2; V3; GSA; GSA; headaches;
CN V - Trigeminal Nerve
- Sensory - (V1 and V2/V3)
- Mixed - (V1 and V2/V3)
- Proprioceptive input from muscles of mastication, TMJ and teeth
- Coordination of biting and chewing
- (GSE/GSA)
- Motor: (V1 and V2/V3)
- Muscles of (mastication/defecation)
- Tensor tympani
- Stiffens tympanic membrane to keep it from over vibrating and potentially being damaged
- Soft palate elevation
V1 and V2; V3; GSA; V3; mastication
