Exam3Lec6CranialNerves Flashcards
Name all Cranial nerves
I. Olfactory
II. Optic
III.Oculomotor
IV.Trochlear
V. Trigeminal
VI. Abducens
VII. Facial
VIII.Vestibulocochlear
IX. Glossopharyngeal
X. Vagus
XI. Spinal (Accessory)
XII. Hypoglossal
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olfactory and optic are NOT in brain stem, it’s in the brain
Which nerves are sensory only, motor only, and mixed?
Sensory Only: 1 (smell),2 (sight),8 (hearing)
Motor only: CN 3,4,6,11,12
Both (mixed): CN 5,7,9,10
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What is the axon pathway of the olfactory nerve (CN 1)
nasal axons (bipolar neurons)–> cribriform plate–> olfactory bulb–> olfactory n.
Where does the olfactory nerve enter and what is its innervation?
enters via cribriform plate (ant. fossa)
innervation=sensory only
Where does the optic nerve (CNII) enter, where are the axons formed from, innervation, and visual pathway
- enters the skull via optic canal (middle fossa)
- axons formed from the cells in the retina of the eye (covered by oligodendrocytes in CNS)-This point is low yield
- innervation: sensory only
- Visual pathway: retina–> optic n. –> visual cortex (brain) this point is low yield
What is the optic nerve pathway?
optic nerve–> optic chiasm–> optic tract–> LGB (thalamus)–> optic radiation–> visual cortex
medial retina crosses @ optic chiasm & lateral retina remains ipsilateral (this means that the lateral stays on the same side)
What occurs in this CN II visual pathway defect?
Partial defect of right optic n.
partial loss of peripheral vision of right eye
What occurs in this CN II visual pathway defect?
Complete defect of right optic n.
total blindess of right eye
What occurs in this CN II visual pathway defect?
Complete defect of optic chiasm
loss of lateral visual field of both eyes
What occurs in this CN II visual pathway defect?
Complete defect of right optic tract
loss or left visual fields in both eyes
What occurs in this CN II visual pathway defect?
partial defect of right optic tract
loss of medial visual field of right eye
What occurs in this CN II visual pathway defect?
Complete defect of right optic radiation
loss of left visual field in both eyes
What occurs in this CN II visual pathway defect?
Complete defect of right visual cortex
loss of left visual field in both eyes
Where does the Oculomotor nerve (CNIII) nerve enter?
enters the orbit (skull) via superior orbital fissue (middle fossa)
runs through cavernous sinus alongside trochlear (CN 4) + abducens (CN6)
What is the innervation of oculomotor nerve?
Motor to the eye–> sup./med./inf. rectus + inf oblique
except for sup. obliquw (CN4) + lateral recuts (CN6)
What is the parasympathetic innervation for the oculomotor nerve?
parasympathetic fibers–> short ciliary nerves–> innervates ciliary muscle + constrictor pupillae–> mediates light + accommodation reflexes
Where does the trochlear nerve (CN IV) enter?
enters the skull via superior orbital fissure (middle fossa)
runs through the cavernous sinus alongside oculomotor (CN 3) + abducens (CN 6)
Where does the trochlear nerve (CN IV) exit?
exit the skull (brainstem) inferiorly to the inferior colliculus
only cranial n. that is crossed before leaving brainstem
What is the innervation of the trochlear nerve?
motor to the eye–> superior oblique m.
trochlear n. palsy can cause torticollis–> affects SCM
What are the branches of the trigeminal nerve (CN V)
V-1: opthalmic-> enters skull via superior orbital fissue (middle fossa)
V-2: maxiallry-> enters skull via foramen rotundum (middle fossa)
V-3: mandobular-> enters skull via formaen ovale (middle fossa
FYI largest cranial nerve