Occulomotor nerve palsy causes all, except:
Correct Answer: Miosis
Description: Oculomotor nerve palsy is an eye condition resulting from damage to the third cranial nerve or a branch thereof. As the name suggests, the oculomotor nerve supplies the majority of the muscles controlling eye movements.
Thus, damage to this nerve will result in the affected individual being unable to move his or her eye normally. In addition, the nerve also supplies the upper eyelid muscle (Levator palpebrae superioris) and the muscles responsible for pupil constriction (sphincter pupillae).
The eye will be displaced outward and displaced downward; outward because the lateral rectus (innervated by the sixth cranial nerve) maintains muscle tone in comparison to the paralyzed medial rectus. The eye will be displaced downward, because the superior oblique (innervated by the fourth cranial or trochlear nerve), is unantagonized by the paralyzed superior rectus, inferior rectus and inferior oblique.
The affected individual will also have a ptosis, or drooping of the eyelid, and mydriasis (pupil dilation).
Category:
Anatomy
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