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Ophthalmology Ocular Motility 654c13a8

Oculomotor nerve palsy causes all except:

A
Miosis
B
Ptosis
C
Outward eye deviation
D
Diplopia
High-Yield Explanation
Ans. a. Miosis Occulomotor nen'e innervates 4 extraocular muscles (i.e. RIMS = rectus of inferior, medial and superior; and inferior oblique/ in addition to levator pulpebrae and pupillary sphincter. So when the palsy is complete, there is complete ptosis with a dilated pupil (mydriasis, not the miosis). The eye is deviated out (laterally) and usually, but not always, down.Oculomotor Nerve * The III cranial nerve innervates the medial, inferior and superior recti, inferior oblique, levator palpebrae superioris and the iris sphincter.* Total palsy of the oculomotor nerve causes ptosis, results in a dilated pupil (mydriasis), and leaves | they eye "down and out' because of the unopposed action of the lateral rectus and superior oblique. I* The patient complains of diplopia due to paralysis of these extraocular muscles.* In the setting of early or partial oculomotor palsy, any combination of ptosis, pupil dilation and weakness of the eye muscles supplied by the nerve maybe encountered.Oculomotor Nerve ProvidesMotor supply toParasympathetic supply through the ciliary ganglion toProprioception to* Levator palpebrae superioris* Superior rectus* Medial rectus* inferior recuts* Inferior oblique &* Inferior oblique* Sphincter pupiliae (which causes constriction of pupil)* Ciliary body (which produces accommodation)* Levator palpebrae superioris* Superior rectus* Medial rectus* Inferior recuts* Inferior oblique* Inferior oblique

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