What occurs with the affected eye when there is paralysis of CN III?

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When there is paralysis of cranial nerve III (oculomotor nerve), the affected eye typically exhibits a specific positioning due to the imbalance of muscle control. The oculomotor nerve is responsible for innervating several extraocular muscles that control eye movement, including the muscles that elevate the eye and turn it inward.

In cases of CN III paralysis, the unopposed action of the lateral rectus muscle, which is innervated by cranial nerve VI (abducens nerve), causes the affected eye to be deviated outward. This outward pull results in the eye being constantly turned laterally. Additionally, the paralysis may lead to other symptoms such as ptosis (drooping of the eyelid) and dilation of the pupil, but the specific outward position of the eye is a hallmark sign of CN III dysfunction.

Therefore, the consequence of paralysis of cranial nerve III is that the affected eye appears pulled outward, demonstrating the characteristic feature associated with this type of nerve injury.

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