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10 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What are the special sense nerves |
Cranial nerve I :smell
Cranial nerve II :optic nerve
Cranial nerve VIII :Hearing |
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What are the somatic motor nerves (eye muscles) |
All 3 nerves pass through the superior orbital fissure. Cranial nerve IV (trochlear) :target-> superior oblique Only CN to decussates and exits from the dorsal aspect of the brainstem. It pierces the dura mater moves along the lateral wall of the cavernous sinus then through SOF to orbit Is supseptable to injury from blows to back of head and whiplash injury
Cranial nerve VI (Abducens) :target-> lateral rectus Arises from the abducens nucleus in the pons of brain stem and exits at the junction of the pons and the medulla It then enters the subarachnoid space and pierces the dura mater to travel in the dorello canel. Then enters the cavernous sinus at the tip of the petrous temporal bone until arrives at orbit through the superior orbital fissure. More acceptable to injury as it can be pinched by petrous temporal bone. More acceptable to injury as long journey from brainstem to eye. Nucleus located in pons
Cranial nerve III (Oculomotor) :target->superior, medial, inferior rectus, inferior oblique and lavator palpebrae superioris. Innervates DILATION OF PUPIL and CILIARY MUSCLES
NUCLEUS IS SUB-DIVIDED Originates from the anterior aspect of the midbrain(above pons), passes below the posterior cerebral artery and above the superior cerebellar artery, pierces the dura mater and enters the lateral aspect of the cavernous sinus. Through the superior orbital fissure, it then splits into 2 branches; superior and inferior branches which head to the top and bottem of the eye.
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LR6 SO4 (everything else is 3) |
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What does the lateral palpebrae superioris do |
Responsible for superior eyelid movement (Only muscle involved in this) Originates from the less bone of the sphenoid bone |
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What are the different terms for eye movement |
Elevation=up Depression=down Abduction=out Adduction=in Intorsion=towards nose Extorsion=away from nose |
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Where do the rectus muscles originate from |
Common tendinous ring (Ring of fibrous tissue surrounding the optic nerve at orbit apex) |
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What do the rectus muscles do |
Superior muscle main action is elevation, adduction and intorsion
Inferior muscle main action is depression, adduction and extorsion
Medial muscle acts to adduct the eyeball
Lateral muscle acts to abduct the eyeball |
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Where do the oblique muscles originate from |
Superior oblique From the body of the sphenoid bone Inferior oblique From the medial side of the orbital floor |
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What do the oblique muscles do |
Superior oblique acts to depress, abduct and intort the eyeball.
Inferior oblique acts to elevate, abduct and extort eyeball. |
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What are the bones surrounding the left orbital |
Left side=zygomatic bone Bottem=maxilla and palitine bone Right side=lacrimal and ethmoid bone Back side=sphenoid bone |
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Bh |
B |
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